% % converted from refer format by refer-to-bibtex 0.9.3 -- 17:08, 9 Mar 112 % r2b t2 % @article{BRL999, author = {{XXX}}, title = {{YYY}}, institution = {XXX}, journal = {ZZZ}, contents = {999} } @incollection{BRL237, title = {Chapter 24 Macro and Micro Soft Tissue Biomechanics and Tissue Damage: Application in Surgical Robotics}, booktitle = {Surgical Robotics: Systems Applications and Visions}, pages = {583-618}, publisher = {Springer, Berlin, Heidelberg}, year = {2011}, annote = {http://tinyurl.com/SRSAVRosen}, abstract = {Accurate knowledge of biomechanical characteristics of tissues is essential for developing realistic computer-based surgical simulators incorporating haptic feedback, as well as for the design of surgical robots and tools. Most past and current biomechanical research is focused on soft and hard anatomical structures that are subject to physiological loading while testing the organs in situ. Internal organs are different in that respect since they are not subject to extensive loads as part of their regular physiological function. However, during surgery, a different set of loading conditions are imposed on these organs as a result of the interaction with the surgical tools. The focus of the current study was to obtain the structural biomechanical properties (engineering stress-strain and stress relaxation) of seven abdominal organs, including bladder, gallbladder, large and small intestines, liver, spleen, and stomach, using a porcine animal model. The organs were tested in vivo, in situ, and ex corpus (the latter two conditions being postmortem) under cyclical and step strain compres sions using a motorized endoscopic grasper and a universal-testing machine. The tissues were tested with the same loading conditions commonly applied by surgeons during minimally invasive surgical procedures. Phenomenological models were developed for the various organs, testing conditions, and experimental devices. A property database—unique to the literature—has been created that contains the average elastic and relaxation model parameters measured for these tissues in vivo and postmortem. The results quantitatively indicate the significant differences between tissue properties measured in vivo and postmortem. A quantitative understanding of how the unconditioned tissue properties and model parameters are influenced by time postmortem and loading condition has been obtained. The results provide the material property foundations for developing science-based haptic surgical simulators, as well as surgical tools for manual and robotic systems.}, contents = {237} } @incollection{BRL238, author = {J. Rosen and M. Lum and M. Sinanan and B. Hannaford}, title = {Chapter 8: Raven: Developing a Surgical Robot from a Concept to a Transatlantic Teleoperation Experiment}, booktitle = {Surgical Robotics: Systems Applications and Visions}, pages = {159-197}, publisher = {Springer, Berlin, Heidelberg}, year = {2011}, annote = {http://tinyurl.com/SRSAVRosen}, abstract = {For decades surgery and robotics were progressing along two parallel paths. In surgery, minimally invasivesurgery (MIS) revolutionized the way a significant number of surgical interventions were performed. Minimally invasive surgery allows the surgeon to make a few small incisions in the patient, rather than making one large incision for access. This technique allows for significantly faster recovery times, less trauma, and decreased pain medication requirements for the patient. In robotics, teleoperation integrated the human into robotic systems. Only in the last decade have surgery and robotics reached a level of maturity that allowed safe assimilation between the two in a teleoperation mode for creating a new kind of operating room with the potential for surgical innovation long into the future [1]. A detailed historical overview of surgical robotics is beyond the scope of this chapter. The reader may refer to several published papers, which collectively may provide a comprehensive survey of the field of surgical robotics and its applications in various sub-disciplines of surgery and medicine [2–17]. The remaining of this section will provide a brief overview of key systems and millstones of the research activities in the field of surgical robotics and telesurgery.}, contents = {238} } @incollection{BRL236, author = {L.N.Sekhar and D, Ramanathan, and J. Rosen and L.J. Kim and D. Friedman and D. Glozman and K. Moe and T. Lendvay and B. Hannaford}, title = {Chapter 30 Robotics in Neurosurgery}, booktitle = {Surgical Robotics: Systems Applications and Visions}, pages = {723-742}, publisher = {Springer, Berlin, Heidelberg}, year = {2011}, annote = {http://tinyurl.com/SRSAVRosen}, abstract = {Use of robots in surgery, especially in neurosurgery, has been a fascinating idea since the development of industrial robots. Using the advantages of a robot to comple- ment human limitations could potentially enhance surgical possibilities, other than making it easier and safer. Over the last few decades, much progress has been made in this direction across various disciplines of neurosurgery such as cranial surgery, spinal surgery and radiation therapy. This chapter details the necessity, principles and the future directions of robotics in neurosurgery. Also, the concept of curvilinear robotic surgery and associated instrumentation is discussed. The idea of using robots in surgery has fascinated surgeons since the making of the first robots for industrial and military use. The first robots were developed in the late fifties for use in industry mainly as transfer machines, used for transporting objects across a few feet. Further design modifications with articulated multi axial arms helped in the making of robots such as Stanford Arm and Programmable Universal Machines for Assembly (PUMA), which were used for automation of manufacturing processes.}, contents = {236} } @book{BRL235, editor = {J. Rosen and R. Satava}, title = {B. Hannaford Surgical Robotics: Systems Applications and Visions}, pages = {819}, publisher = {Springer, Berlin, Heidelberg}, year = {2011}, annote = {http://tinyurl.com/SRSAVRosen}, contents = {235} } @incollection{BRL223, author = {B. Hannaford and R. Leuschke}, editor = {M. Lin and M. A. Otaduy}, title = {Rendering for Multifinger Haptic Devices}, booktitle = {Haptic Rendering, Foundations, Algorithms, and Applications}, pages = {67-82}, publisher = {A.K. Peters, Co. Wellesley, MA}, year = {2008}, contents = {223} } @incollection{BRL222, author = {B. Hannaford and A. Okamura}, editor = {B. Siciliano and O. Khatib}, title = {Haptics}, booktitle = {Springer Handbook of Robotics (Winner of two 2008 PROSE Awards, American Association of Publishers)}, publisher = {Springer, Berlin, Heidelberg}, year = {2008}, abstract = {An overview on Haptics in this huge encylopedia on Robotics.}, contents = {222} } @incollection{BRL186, author = {B. Hannaford and J.H. Ryu and Y.S. Kim}, editor = {Margaret L. McLaughlin}, title = {Chapter 3 Stable Control of Haptics}, booktitle = {Touch in Virtual Environments}, pages = {47-70}, publisher = {Prentice Hall PTR, IMSC Press Multimedia Series}, year = {2001}, abstract = {Humans interact with their surrounding environment through five sensory channels, popularly labeled "sight," "sound," "taste," "smell," and "touch." It is our sense of touch which provides us with much of the information necessary to modify and manipulate the world around us. The word haptic refers to something of or relating to the sense of touch: conveying information on physical properties such as inertia, friction, compliance, temperature, and roughness. This sense can be divided into two categories: the kinesthetic sense, through which we sense movement or force in muscles and joints; and the tactile sense, through which we sense shapes and textures. This chapter will focus on the stable control of devices and systems which support hap- tic interaction, especially relating to the use of kinesthetic sense in virtual environments.}, contents = {186} } @incollection{BRL185, author = {J.H. Ryu and D.S. Kwon and B. Hannaford}, editor = {Antonio Bicchi and Henrik I. Christensen and Domenico Prattichizzo}, title = {Control of a Flexible Manipulator with Noncollocated Feedback: Time Domain Passivity Approach}, booktitle = {Control Problems in Robotics}, volume = {4}, pages = {121-134}, publisher = {Springer Tracts in Advanced Robotics Series}, year = {2003}, abstract = {A new method to control a flexible manipulator with noncollocated feedback is proposed. We introduce a method to implement the time domain passivity control approach to a flexible manipulator with noncollocated feedback, which could not betreated with the previous time domain passivity control framework due to a possibly active transfer function from the collocated output to the noncollocated output. The developed method is simulated with the model of a single link flexible manipulator and we obtained a good control performance.}, contents = {185} } @incollection{BRL184, author = {B. Hannaford and J.H. Ryu and D.S. Kwon and Y.S. Kim and J.B. Song}, title = {Testing Time Domain Passivity Control of Haptic Enabled Systems}, booktitle = {Experimental Robotics}, volume = {5}, pages = {550-559}, publisher = {Springer Tracts in Advanced Robotics Series}, month = {Bruno Siciliano and Paolo Dario}, year = {2003}, abstract = {Much recent work has studied the means of achieving stable yet high performance control of haptic interfaces. Such interfaces provide compelling force feedback in virtual reality simulations for medical training, advanced computer aided design (CAD), entertainment, and other applications. This paper reports experimental testing of a new method of stable haptic interface control, the Passivity Observer (PO) and Passivity Controller (PC). Experimental results from three different laboratories confirm basic operation of the PO/PC. The PO/PC method is applied to high stiffness haptic interaction, to a 2-degree-of-freedom (DOF) system with coupled kinematics and dynamics, and to a bi-lateral telemanipulation system controlling metal-to-metal contact.}, contents = {184} } @article{BRL178, author = {J.E. Speich and J. Rosen}, editor = {G. Wnek and G. Bowlin}, title = {Medical Robotics}, journal = {In Encyclopedia of Biomaterials and Biomedical Engineering}, pages = {983-993}, publisher = {Marcel Dekker}, address = {New York}, year = {2004}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep178.pdf}, abstract = {[This is an encylopedia article - no abstract available]}, contents = {178} } @article{BRL160, author = {B. Hannaford and J.H. Ryu and D.S. Kwon and Y.S. Kim and J.B. Song}, title = {Testing Time Domain Passivity Control of Haptic Enabled Systems}, journal = {University of Washington Department of Electrical Engineering Technical Report number UWEETR-2002-0010}, month = {19-July-}, year = {2002}, annote = {https://www.ee.washington.edu/techsite/papers/documents/UWEETR-2002-0010.pdf}, abstract = {Much recent work has studied the means of achieving stable yet high performance control of haptic interfaces. Such interfaces provide compelling force feedback in virtual reality simulations for medical training, advanced computer aided design (CAD), entertainment, and other applications. This paper reports experimental testing of a new method of stable haptic interface control, the Passivity Observer (PO) and Passivity Controller (PC). Experimental results from three different laboratories confirm basic operation of the PO/PC. The PO/PC method is applied to high stiffness haptic interaction, to a 2-degree-of-freedom (DOF) system with coupled kinematics and dynamics, and to a bi-lateral telemanipulation system controlling metal-to-metal contact.}, contents = {160} } @article{BRL158, author = {B. Hannaford and J.H. Ryu}, title = {Time domain passivity control of haptic interfaces}, journal = {U.S. Patent \# 7,027,965}, month = {11-April-}, year = {2006}, abstract = {Methods are provided for stabilizing a haptic interface of a computer-controlled one-port virtual-reality system or a two-port teleoperation system comprising a robot manipulator. "Stabilizing" means to reduce the sense of vibration in a haptic interface. A Passivity Observer is computed to measure the amount of energy produced at the haptic interface, and a Passivity Controller is calculated to damp or absorb excess energy which causes the sense of vibration. This invention also provides a "filter," i.e. a threshold function which returns zero velocity if the computed estimated velocity is less than a small predetermined value, which may be applied to estimated velocities determined in impedance-based methods of this invention so as to remove noise in the velocity estimate. To improve speed of reaction of the systems, this invention also provides methods for resetting the Passivity Observer to zero when it has been too positive for too long a period of time. Systems implementing these methods are also provided.}, contents = {158} } @article{BRL140, author = {S.C. Venema and E. Matthes and B. Hannaford}, title = {Flat Coil Actuator having Coil Embedded in Linkage}, journal = {U.S. Patent \#6,437,770}, month = {20-August-}, year = {2002}, abstract = {A flat-coil actuator embedded in a linkage of a mechanical interface for a force feedback device. The linkage rotates about an axis, where a flat coil is embedded in the linkage between two ends or connection points of the linkage. Magnets are positioned parallel to the flat coil, where a force is produced on the linkage when a current is flowed in the coil. An embedded position sensor, such as an optical encoder, can be coupled to the linkage. A force feedback device incorporating the flat-coil actuator includes a user manpulandum, where the linkage is coupled between a ground and the user manipulandum. Other linkages can also be coupled to the actuator to provide mechanisms such as a five-bar linkage mechanism.}, contents = {140} } @incollection{BRL139, author = {S.C. Venema and B. Hannaford}, editor = {Ken Goldberg and Roland Siegwart}, title = {Telerobotic Remote Handling of Protein Crystals via an Internet Link}, booktitle = {Beyond Webcams, An Introduction to Online Robots}, publisher = {MIT Press}, address = {Cambridge, MA}, year = {2002}, abstract = {A combined University / Industry team has developed a prototype system for handling protein crystals aboard the space station. The system used a miniature direct drive robot, CCD television cameras, and a client-server computing system using internet protocols to support the capture of protein crystals from aqueous growth solutions. The system was demonstrated between Huntsville AL. and Seattle WA. An operator in Huntsville controlled the mini robot by invoking pre-defined relative and absolute macros. The movement macros (a predefined sequence of multi-device movement commands) were developed to support precision motion between task locations in the glovebox. The oper-ator invoked the macros by clicking icons in the remote control interface. The system is a promising start for the development of a space-station based remote protein crystal analysis facility.}, contents = {139} } @incollection{BRL127, author = {B. Hannaford}, editor = {J.K. Goldberg}, title = {Feeling is Believing: Haptics and Telerobotics Technology}, booktitle = {The Robot in the Garden, Telerobotics and Telepistomology on the Internet.}, publisher = {MIT Press}, address = {Cambridge, MA}, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep127/TE.chapt.html}, abstract = {Teleoperation and telerobotics are technologies that support physical action at a distance. This distance could span a few yards though a radioactivity-proof wall, or millions of miles through a vacuum to another planet. Although this book focuses on the relatively recent class of examples where the distance between operator and robot is spanned by the Internet, this chapter summarizes the broader research subject of teleoperation. Teleoperators and telerobots interpose distortion between the operator and the environment. This distortion is sometimes a necessary drawback of the system, or it may be intentionally introduced to produce a useful result like magnification. In either case, these distortions pose fundamental questions of telepistemology which the chapter will highlight rather than answer. $<$p$>$ The chapter will focus on the issues of time delay, control, and stability, with illustrations from the history of telerobotics and teleoperation. It is impossible to do justice to all of the important technologies and the innovative engineers who developed teleoperation in a short chapter, so I will present only a sample of the key ideas. Telerobotics remains an active research area pursued by engineers internationally.}, contents = {127} } @article{BRL119, author = {P. Buttolo and B. Hannaford}, title = {Direct Drive Manipulator for pen-based force display}, journal = {U.S. Patent \#5,642,469}, month = {June 24}, year = {1997}, annote = {http://www.patents.ibm.com/details?patent\_number=5642469}, abstract = {pen-based direct-drive manipulator enables precision manipulation and force display of a control point within three degrees of freedom. The control point exhibits substantially no backlash, very low friction and very low inertia making it useful as a force display. The manipulator also has a very high force generation bandwidth allowing high frequency force components to be displayed. A parallel actuator structure controls motion over two degrees of freedom in a horizontal plane. The parallel structure is a redundant structure including three chains in parallel coupled at the control point. The redundant structure provides a uniform force capability throughout the manipulator workspace. A pair of rotational actuators rotate the parallel structure about an axis to approximate a linear motion along a third axis. The rotational actuators provide a third degree of freedom for the control point. Motion about the third axis is substantially decouple from motion about the horizontal plane.}, contents = {119} } @article{BRL118, author = {R. Seubert and M.V. Olson and D. Meldrum and B. Hannaford and P. Wiktor and N.A. Friedman and D.B. Snow and R. Kraft}, title = {Precision small volume fluid processing apparatus}, journal = {U.S. Patent \#5,785,926}, month = {July 28}, year = {1998}, annote = {http://www.patents.ibm.com/details?patent\_number=5785926}, abstract = {A high precision, small volume fluid processing system employs open ended capillary tubes to meter, aliquot and mix small volumes of sample fluid and reagents. The system has an automatic mechanism for moving the capillary tubes as well as automated sub-systems for incubating and mixing fluids within the capillary tubes.}, contents = {118} } @incollection{BRL110, author = {B. Hannaford}, editor = {D. Hemmendinger and A. Ralston}, title = {Telerobotics}, booktitle = {Encyclopedia of Computer Science}, edition = {4th}, publisher = {McMillan}, month = aug, year = {2000}, annote = {http://tardis.union.edu/\~{}hemmendd/Encyc/}, abstract = {Telerobotics connotes the technology of robotics controlled at a distance by human beings. When a task involving physical exploration, manipulation, and sampling is too dangerous or impractical to be performed directly by a human being it may be suited to a telerobot. In such a system, the human operator is physically removed from the task, sends commands to the robot over a telecommunication system, and receives information about the status of the task and its environment. Teleoperation therefore involves augmenting, supervising, or substituting artificial intelligence and control functions of the robot with the intelligence and pattern recognition abilities of the human operator. $<$p$>$ This article will describe some of the applications, challenges, and technologies of modern telerobotic systems while concentrating primarily on remote manipulation. Most of the ideas in this article will be applicable to other major segments of telerobotics, namely remote control of vehicles or mobile robots, and micromanipulation systems.}, contents = {110} } @article{BRL103, author = {B. Hannaford and M.R. Moreyra and P.H. Marbot}, title = {Five axis direct-drive mini-robot having fifth actuator located at a non-adjacent joint}, journal = {U.S. Patent \#5,528,955}, month = {June 25}, year = {1996}, annote = {http://patent.womplex.ibm.com/details?patent\_number=5528955}, abstract = {A substantially balanced, five-axis, direct drive mini-robot provides repeatable micro-manipulation to micron precision. Dynamic forces of each link are nearly decoupled from the dynamic forces of remaining links. The robot is generally formed as a shoulder, arm and wrist assembly. At the shoulder a linear actuator drives the robot in a linear horizontal movement along a first axis (e.g., z axis). Two additional actuators at the shoulder provide revolute motion to rotate the arm in an xz plane (e.g., for lateral motion) and a yz plane (e.g., for vertical motion), respectively. A fourth actuator provides rotational motion to move an end-effector (manipulator) at the wrist through a yaw motion. A fifth actuator, positioned at the shoulder and linked to the wrist, provides rotational motion to move the end-effector through a pitch motion. $<$p$>$ 12 Claims, 7 Drawing Sheets.}, contents = {103} } @incollection{BRL090, author = {M. Moreyra and P.H. Marbot and S. Venema and B. Hannaford}, editor = {V. Graefe}, title = {A 5-Axis Mini Direct Drive Robot for Time Delayed Teleoperation}, booktitle = {Intelligent Robots and Systems 1994}, pages = {445-462}, publisher = {Elsevier Science}, year = {1995}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep090.pdf}, abstract = {A previously developed 3-axis mini direct drive robot has been enhanced with two additional direct drive axes for general positioning and orientation of an axially symmetric tool. The arm has a work volume of about 120 and 5-10 or better resolution and repeatability. The arm forms an initial prototype for the NASA/University of Washington MicroTrex flight telerobotics experiment. The contemplated terrestrial applications include handling sub-microliter liquid samples for electrophoresis, and micro-manipulation with scaled force reflection.}, contents = {090} } @incollection{BRL074, author = {B. Hannaford}, editor = {S.B. Skaar}, title = {Ground Experiments towards Space Teleoperation with Time Delay}, booktitle = {Manipulation, Automation, and Robotics in Space}, pages = {87-106}, publisher = {AIAA}, year = {1994}, abstract = {An important component of research into advanced telemanipulation systems is performance evaluation. Advances in computation, mechanization, and control must be calibrated in terms of measurable improvements in manipulation performance. Performance evaluation of telemanipulators is a difficult task which of necessity involves many test operators, training sessions, and well- defined evaluation tasks. Literature on many studies of this type performed over the past 20 years is surveyed in Hannaford, et al. (1989, 1991). In all teleoperation systems, some time delay will be present in the communication between master and slave sub-systems. Because of the large distances involved, this delay is especially prominent in contemplated applications in space. Early Studies such as Sheridan and Ferrell (1963), looked at the effects of time delay on the control of a remote manipulator without force feedback. A study by Ferrell (1966) found force feedback to be useful with time delay, but revealed degradation of performance and potential for unstable operation. More recently, studies have simulated time delay with digital memory buffers and studied its effect on teleoperation with force reflection in single axis (Hannaford and Anderson, 1988; Lawn and Hannaford, 1989), and multi-axion systems (Kim, et al., 1992). Since early teleoperators were first remotized electronically, reflection of force information to the operator was recognized as a key to higher performance remote manipulation. Many force reflecting teleoperation systems are implemented by sending a position or velocity signal from master to slave and a force signal from slave back to master. In this scheme, the communication delay appears twice in a larger system involving human operator, hand controller, communication link, slave robot, and environment. It has been widely observed that this delay can cause instability of the force reflecting control system.}, contents = {074} } @incollection{BRL073, author = {B. Hannaford and S. Venema}, editor = {W. Barfield and T. Furness}, title = {Kinesthetic Displays for Remote and Virtual Environments}, booktitle = {Virtual Environments and Advanced Interface Design}, pages = {415-436 415-436}, publisher = {Oxford}, year = {1995}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep073.pdf}, abstract = {Humans perceive their surrounding environment through five sensory channels, popularly labeled "sight," "sound," "taste," "smell," and "touch." All of these modalities are fused together in our brains into an apparently seamless perception of our world. While we typically place the most importance on our visual sense, it is our sense of touch which provides us with much of the information necessary to modify and manipulate the world around us. This sense can be divided into two categories: the kinesthetic sense, through which we sense movement or force in muscles and joints; and the tactile sense, through which which we shapes and textures. This chapter will focus on the use of kinesthetic sense in realistic teleoperation and virtual environment simulations.}, contents = {073} } @article{BRL234, author = {P. Roan and A.S. Wright and M. N. Sinanan and B. Hannaford}, title = {An Instrumented Minimally Invasive Surgical Tool: Design and Calibration}, journal = {Applied Bionics and Biomechanics}, volume = {Special Issue on Surgical Robotics}, year = {2010}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep234.pdf}, abstract = {Minimally invasive surgical procedures have improved the standard of patient care by reducing recovery time, chance of infection, and scarring. A recent review estimates that leaks occur in 3$\backslash$\% to 6$\backslash$\% of bowel anastomoses, resulting in “increased morbidity and mortality and adversely [affecting] length of stay, cost, and cancer recurrence” (Kingham and Pachter 2009). Many of these leaks are caused by poor handling and ischemic tissue. $<$p$>$Detecting a change in temperature can indicate ischemic tissue. The optical absorption spectrum of a tissue can be used to detect tissue oxygen concentration and tissue ischemia. The electrical impedance of tissue changes as ischemia progresses. $<$p$>$This article describes the development of a minimally invasive surgical tool with integrated sensors for replicating ischemia detection measurements during routine manipulation of the tissue. To be useful, this tool should be feasible for use in a real operating room, providing real-time feedback and diagnosis to the surgeon. The design of the tool and choice of the sensors leverages existing work in physiological measure- ments and surgical tool design. $<$p$>$The tool includes a thermistor for measuring the temperature, four LEDs and a photodiode for measuring local optical absorption, and four electrodes for measuring the electrical impedance. The sensors are located on a 7 mm square sensor head, which is mounted to a minimally invasive grasper. A strain gauge and optical encoder monitor the applied force and position of the tool, and a motor controls both. This allows the tool to control the tool-tissue interface. Sensor accuracy has been validated through calibration.}, contents = {234} } @article{BRL233, author = {D.W. Friedman and T. Kowalewski and R. Jovanovic and J. Rosen and B. Hannaford}, title = {Freeing the Serial Mechanism Designer from Inverse Kinematic Solvability Constraints}, journal = {Applied Bionics and Biomechanics}, volume = {7}, number = {3}, pages = {209-216}, year = {2010}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep233.pdf}, abstract = {This paper presents a fast numerical solution for the inverse kinematics of a serial manipulator. The method is implemented on the C-Arm, a manipulator designed for use in robotic surgery. The inverse kinematics solution provides a solution for any six degree-of-freedom serial manipulator, assuming the forward kinematics are known and that it is possible to solve for the remaining joint angles if one joint angle’s value is known. With a fast numerical method and the current levels of computing power, designing a manipulator with closed-form inverse kinematics is no longer necessary. When designing the C-Arm, we therefore chose to weigh other factors, such as actuator size and patient safety, more heavily than the ability to find a closed-form inverse kinematics solution.}, contents = {233} } @article{BRL220, author = {M. Lum and D. Friedman and J. Rosen and G. Sankaranarayanan and H. King and K. Fodero and R. Leuschke and M. Sinanan and B. Hannaford}, title = {The {RAVEN} - Design and Validation of a Telesurgery System}, journal = {International Journal of Robotics Research}, volume = {28}, pages = {1183-1197}, month = sep, year = {2009}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep220.pdf}, abstract = {The collaborative effort between fundamental science, engineering and medicine provides physicians with improved tools and techniques for delivering effective health care. Minimally invasive surgery (MIS) techniques have revolutionized the way a number of surgical procedures are performed. Recent advances in surgical robotics are once again revolutionizing MIS interventions and open surgery. In an earlier research endeavor, thirty surgeons performed seven different MIS tasks using the Blue Dragon system to collect measurements of position, force, and torque on a porcine model. This data served as the foundation for a kinematic optimization of a spherical surgical robotic manipulator. Following the optimization, a 7-DOF cable-actuated surgical manipulator was designed and integrated, providing all degrees of freedom present in manual MIS as well as wrist joints located at the surgical end-effector. The RAVEN surgical robot system has the ability to teleoperate utilizing a single bi-directional UDP socket via a remote master device. Preliminary telesurgery experiments were conducted using the RAVEN. The experiments illustrated the system’s ability to operate in extreme conditions using a variety of network settings.}, contents = {220} } @article{BRL217, author = {J. Rosen and J. Brown and S. De and M. Sinanan and B. Hannnaford}, title = {Biomechanical Properties of Abdominal Organs In Vivo and Postmortem Under Compression Loads}, journal = {J. Biomechancal Engineering}, volume = {130}, number = {2}, month = {8-Apr-}, year = {2008}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep217.pdf}, abstract = {Accurate knowledge of biomechanical characteristics of tissues is essential for developing realistic computer-based surgical simulators incorporating haptic feedback, as well as for the design of surgical robots and tools. As simulation technologies continue to be capable of modeling more complex behavior, an in vivo tissue property database is needed. Most past and current biomechanical research is focused on soft and hard anatomical structures that are subject to physiological loading, testing the organs in situ. Internal organs are different in that respect since they are not subject to extensive loads as part of their regular physiological function. However, during surgery, a different set of loading conditions are imposed on these organs as a result of the interaction with the surgical tools. Following previous research studying the kinematics and dynamics of tool/tissue interaction in real surgical procedures, the focus of the current study was to obtain the structural biomechanical properties (engineering stress-strain and stress relaxation) of seven abdominal organs, including bladder, gallbladder, large and small intestines, liver, spleen, and stomach, using a porcine animal model. The organs were tested in vivo, in situ, and ex corpus (the latter two conditions being postmortem) under cyclical and step strain compressions using a motorized endoscopic grasper and a universal-testing machine. The tissues were tested with the same loading conditions commonly applied by surgeons during minimally invasive surgical procedures. Phenomenological models were developed for the various organs, testing conditions, and experimental devices. A property database—unique to the literature—has been created that contains the average elastic and relaxation model parameters measured for these tissues in vivo and postmortem. The results quantitatively indicate the significant differences between tissue properties measured in vivo and postmortem. A quantitative understanding of how the unconditioned tissue properties and model parameters are influenced by time postmortem and loading condition has been obtained. The results provide the material property foundations for developing science-based haptic surgical simulators, as well as surgical tools for manual and robotic systems.}, contents = {217} } @article{BRL207, author = {S. De and J. Rosen and A. Dagan and P. Swanson and M. Sinanan and B. Hannaford}, title = {Tissue Damage due to Mechanical Stresses as applied during Minimally Invasive Surgery}, journal = {International Journal of Robotics Research}, volume = {26}, pages = {1159-1171}, month = {Nov-}, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep207.pdf}, abstract = {While there are many benefits to minimally invasive surgery, force feedback, or touch sensation, is lacking in the currently available MIS tools, including surgical robots, creating the potential for excessive force application during surgery. The goal of this work was to develop a methodology with which to identify stress magnitudes and durations that can be safely applied with a grasper to different tissues, helping to improve MIS device design and reduce potential for clinically relevant consequences. Using the porcine model, stresses typically applied in MIS were applied to liver, ureter, and small bowel using a motorized endoscopic grasper. Acute indicators of tissue damage including cellular death, activation of the coagulation cascade, and infiltration of inflammatory cells were measured using histological and image analysis techniques. ANOVA and post-hoc analyses were used to detect stress magnitudes and durations that caused significantly increased tissue damage with the goal to ultimately identify safe stress ‘thresholds’ during grasping of the studied tissues. Preliminary data suggests a graded non-linear response between applied stress magnitude and apoptosis in liver and small bowel as well as granulocyte infiltration in small bowel.}, contents = {207} } @article{BRL203, author = {J. Rosen and B. Hannaford}, title = {Doc at a Distance}, journal = {IEEE Spectrum}, pages = {34-39}, month = oct, year = {2006}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep203.pdf}, abstract = {Remote surgeons promise to save lives in remote communities, war zones, and disaster-stricken areas. On a hot morning this past June, our research group at the University of Washington, in Seattle, crammed into two cargo vans and drove 2000 kilometers south to the rangeland north of Simi valle, in soutwestern California. In the back of one of our vans was our latest cration: a prototype surgical robot ...}, contents = {203} } @article{BRL199, author = {J. Rosen and J.D. Brown and L. Chang and M. Sinanan and B. Hannaford}, title = {Generalized Approach for Modeling Minimally Invasive Surgery as a Stochastic Process Using a Discrete Markov Model}, journal = {IEEE Transactions on Biomedical Engineering}, volume = {53}, number = {3}, pages = {399-413}, month = mar, year = {2006}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep199.pdf}, abstract = {Minimally invasive surgery (MIS) involves a multidimensional series of tasks requiring a synthesis between visual information and the kinematics and dynamics of the surgical tools. Analysis of these sources of information is a key step in defining objective criteria for characterizing surgical performance. The Blue DRAGON is a new system for acquiring the kinematics and the dynamics of two endoscopic tools synchronized with the endoscopic view of the surgical scene. Modeling the process of MIS using a finite state model [Markov model (MM)] reveals the internal structure of the surgical task and is utilized as one of the key steps in objectively assessing surgical performance. The experimental protocol includes tying an intracorporeal knot in a MIS setup performed on an animal model (pig) by 30 surgeons at different levels of training including expert surgeons. An objective learning curve was defined based on measuring quantitative statistical distance (similarity) between MM of experts and MM of residents at different levels of training. The objective learning curve was similar to that of the subjective performance analysis. The MM proved to be a powerful and compact mathematical model for decomposing a complex task such as laparoscopic suturing. Systems like surgical robots or virtual reality simulators in which the kinematics and the dynamics of the surgical tool are inherently measured may benefit from incorporation of the proposed methodology.}, contents = {199} } @article{BRL189, author = {M.J.H. Lum and J. Rosen and M. N. Sinanan and B. Hannaford}, title = {Kinematic Optimization of Serial and Parallel Spherical Mechanism for a Minimally Invasive Surgical Robot}, journal = {IEEE Transactions on Biomedical Engineering}, volume = {53}, number = {7}, pages = {1440-1445}, month = jul, year = {2006}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep189.pdf}, abstract = {With a focus on design methodology for developing a compact and lightweight minimally invasive surgery (MIS) robot manipulator, the goal of this study is progress toward a next-generation surgical robot system that will help surgeons deliver healthcare more effectively. Based on an extensive database of in-vivo surgical measurements, the workspace requirements were clearly defined. The pivot point constraint in MIS makes the spherical manipulator a natural candidate. An experimental evaluation process helped to more clearly understand the application and limitations of the spherical mechanism as an MIS robot manipulator. The best configuration consists of two serial manipulators in order to avoid collision problems. A complete kinematic analysis and optimization incorporating the requirements forMIS was performed to find the optimal link lengths of the manipulator. The results show that for the serial spherical 2-link manipulator used to guide the surgical tool, the optimal link lengths (angles) are (60 , 50 ). A prototype 6-DOF surgical robot has been developed and will be the subject of further study.}, contents = {189} } @article{BRL187, author = {D.P. Ferris and J.M. Czerniecki and B. Hannaford}, title = {An ankle-foot orthosis powered by artificial pneumatic muscles}, journal = {Journal of Applied Biomechanics}, volume = {21}, pages = {189-197}, year = {2005}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep187.pdf}, abstract = {Our goal was to develop a powered othosis for the lower limb that could comfortably provide external torque during human walking. We constructued the orthosis from a carbon fiber shell with hinge joint and two artificial pneumatic muscles. One artificial pneumatic muscle provided plantar flexion torque and one artificial pneumatic muscle provided dorsiflexion torque. We collected joint kinematic and artificial muscle force data as one healthy subject walked with the orthosis using proportial myoelectric control. Peak plantar flexor torque provided by the orthosis was 70Nm and peak dorsiflexor torque provided by the orthosis was 38Nm. Soleus and tibialis anterior EMG amplitudes changed in response to powered orthosis assistance. Future studies could use similar powered orthoses to study biomechanics and motor adaptation during human walking or to assist gait rehabilitiation after neurological injury.}, contents = {187} } @article{BRL182, author = {Jee-Hwan Ryu and Dong-Soo Kwon and Blake Hannaford}, title = {Stability Guaranteed Control: Time Domain Passivity Approach}, journal = {IEEE Trans. on Control Systems Technology}, volume = {12}, number = {6}, year = {2004}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep182.pdf}, abstract = {A general framework for expanding the time-domain passivity control approach to large classes of control systems is proposed. We show that large classes of control systems can be described from a network point of view. Based on the network presentation, the large classes of control systems are analyzed in a unified framework. In this unified network model, we define "virtual input energy", which is a virtual source of energy for control, and "real output energy" that is physically transferred to a plant to allow the concept of passivity to be used to study the stability of large classes of control systems. For guaranteeing the stability condition, the time-domain passivity controller for 2-port is applied. Design procedure is demonstrated for a motion control system. The developed method is tested with numerical simulation in the regulation of a single link flexible manipulator. Totally stable control is achieved under wide variety of operating condition and uncertainties without any model information.}, contents = {182} } @article{BRL181, author = {Jee-Hwan Ryu and Dong-Soo Kwon and Blake Hannaford}, title = {Control of a Flexible Manipulator with Noncollocated Feedback: Time Domain Passivity Approach}, journal = {IEEE Trans. on Robotics}, volume = {20}, number = {4}, pages = {776-780}, year = {2004}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep181.pdf}, abstract = {A new method to control a flexible manipulator with noncollocated feedback is proposed. We introduce a method to implement the time domain passivity control approach to a flexible manipulator with noncollocated feedback, which could not be treated with the previous time domain passivity control framework due to a possible active transfer function from the input to the noncollocated output. The proposed method is simulated with a single link flexible manipulator and a good control performance is obtained.}, contents = {181} } @article{BRL180, author = {Jee-Hwan Ryu and Yoon Sang Kim and Blake Hannaford}, title = {Sampled and Continuous Time Passivity and Stability of Virtual Environments}, journal = {IEEE Trans. on Robotics and Automation}, volume = {20}, number = {4}, pages = {772-776}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep180.pdf}, abstract = {We propose new time domain Passivity Observer (PO) and Passivity Controller (PC) which removes the constant velocity assumption during one sample time, which was used in our previous PO/PC approach. A new sampled time definition of passivity is introduced, and this new definition is compared with the previous sampled time definition of passivity. Through this comparison, we propose the more accurate PO/PC approach. The proposed new PO/PC approach is applied to "Excalibur" haptic interface system with very high stiffness (K = 120KN/m) Virtual Envoronment (VE), and stable contact is demonstrated.}, contents = {180} } @article{BRL179, author = {Jee-Hwan Ryu and Carsten Preusche and Blake Hannaford and Gerd Hirzinger}, title = {Time Domain Passivity Control with Reference Energy Behavior}, journal = {IEEE Trans. on Control Systems Technology}, volume = {13}, number = {5}, pages = {737}, month = sep, year = {2005}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep179.pdf}, abstract = {A recently proposed method for stabilizing haptic interfaces and teleoperation systems was tested with a "PHANToM" commercial haptic device. The "Passivity Observer" (PO) and "Passivity Controller" (PC) stabilization method was applied to stabilize the system but also excited a high frequency mode in the device. To solve this problem, we propose a method to use a time-varying desired energy threshold instead of fixed zero energy threshold for the PO, and make the actual energy input follow the time-varying energy threshold. With the time-varying energy threshold, we make the PC control action smooth without sudden impulsive behavior by distributing the dissipation. The proposed new PO/PC approach is applied to PHANToM with high stiffness (K = 500N/m), and stable and smooth contact is guaranteed. Resetting and active environment display problems also can be solved with the reference energy following idea.}, contents = {179} } @article{BRL173, author = {J. Dosher and B. Hannaford}, title = {Human Interaction with Small Haptic Effects}, journal = {PRESENCE}, volume = {14}, pages = {329-344}, month = jun, year = {2005}, abstract = {This research investigated the ability of subjects to detect small haptic effects, and the associated gains in task performance with various confgurations of haptic stimulus. Variations in amplitude, shape, and pulse duration were studied. An adaptive thresholding method was used to obtain detection thresholds for actively explored haptic icons ranging in size from 3 to 5 mm, smooth vs rough actively explored icons, and force pulses of 100 to 150 ms pulse duration. Using Fitts' law. Rough (saw-tooth) haptic icons are more easily detected by a human subject than smooth (sinusoidal) icons of the same size, by almost a factor of two. Mean subject performance, as measured by Fitts' information processing rate and clicks-per-minute, improved with the amplitude of haptic stimulus.}, contents = {173} } @article{BRL172, author = {Jee-Hwan Ryu and Dong-Soo Kwon and Blake Hannaford}, title = {Stable Teleoperation with Time Domain Passivity Control}, journal = {IEEE Trans. on Robotics and Automation}, volume = {20}, number = {2}, pages = {365-373}, month = apr, year = {2004}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep172.pdf}, abstract = {A new bilateral control scheme is proposed to ensure stable teleoperation under a wide variety of operating conditions. System stability is analyzed in terms of the time domain definition of passivity. A previously proposed energy-based method is extended to a 2-port network, and the issues in implementing the "Passivity Observer" and "Passivity Controller" to teleoperation systems are studied. The method is tested with our two-DOF master/slave teleoperation system. Stable teleoperation is achieved under conditions such as hard wall contact (stiffness $>$ 150 kN/m) and hard surface following.}, contents = {172} } @article{BRL162, author = {G Klute and J.M. Czerniecki and B. Hannaford}, title = {Artificial Muscles: Actuators for Biorobotic Systems}, journal = {Intl. Journal of Robotics Research}, volume = {21}, number = {4}, pages = {295-309}, month = apr, year = {2002}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep162.pdf}, abstract = {Biorobotic research seeks to develop new robotic technologies modeled after the performance of human and animal neuromuscular systems. The development of one component of a biorobotic system, an artificial muscle and tendon, is reported here. The device is based on known static and dynamic properties of biological muscle and tendon that were extracted from the literature and used to mathematically describe their force, length, and velocity relationships. A flexible pneumatic actuator is proposed as the contractile element of the artificial muscle and experimental results are presented that show the force-length properties of the actuator are muscle-like, but the force-velocity properties are not. $<$p$>$ The addition of a hydraulic damper is proposed to improve the actuator's velocity-dependent properties. Further, an artificial tendon is proposed whosefunction is to serve as connective tissue between the artificial muscle and a skeletal structure. A complete model of the artificial muscle-tendon system is then presented which predicts the expected force-length-velocity performance of the artificial system. Experimental results of the constructed device indicate muscle-like performance in general: higher activation pressures yielded higher output forces, faster concentric contractions resulted in lower force outputs, faster eccentric contractions produced higher force outputs, and output forces were higher at longer muscle lengths than shorter lengths.}, contents = {162} } @article{BRL161, author = {J. Rosen and M. Solazzo and B. Hannaford and M. Sinanan}, title = {Task Decomposition of Laparoscopic Surgery for Objective Evaluation of Surgical Residents' Learning Curve Using Hidden Markov Model}, journal = {Computer Aided Surgery}, volume = {7}, number = {1}, pages = {49-61}, month = jul, year = {2002}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep161.pdf}, abstract = {$<$b$>$Objective:$<$/b$>$ Evaluation of the laparoscopic surgical skills of surgical residents is usually a subjective process carried out in the operating room by senior surgeons. The two hypotheses of the current study were: (1) haptic information and tool/tissue interactions (types and transitions) performed in laparoscopic surgery are skill-dependent, and (2) statistical models (Hidden Markov Models, HMMs) incorporating these data are capable of objectively evaluating laparoscopic surgical skills. $<$P$>$ $<$b$>$Materials and Methods:$<$/b$>$ Eight subjects (six residentstwo first-year (R1), two third-year (R3), and two fifth-year (R5)and two expert laparoscopic surgeons) performed laparoscopic cholecystectomy on pigs using an instrumented grasper equipped with force/torque (F/T) sensors at the hand/tool interface, and F/T data was synchronized with video of the operative maneuvers. Fourteen types of tool/tissue (T/T) interactions, each associated with unique F/T signatures, were defined from frame-by-frame video analysis. HMMs for each subject and step of the operation were compared to evaluate the statistical distance between expert surgeons and residents with different skill levels. $<$P$>$ $<$b$>$Results:$<$/b$>$ The statistical distances between HMMs representing expert surgeons and residents were significantly different (alpha $<$ 0.05). Major differences occurred in: (1) F/T magnitudes; (2) type of T/T interactions and transitions between them; and (3) time intervals for each T/T interaction and overall completion time. The greatest difference in performance was between R1 (junior trainee) and R3 (midlevel trainee). Smaller changes were seen as expertise increased beyond the R3 level. $<$P$>$ $<$b$>$Conclusion:$<$/b$>$ HMMs incorporating haptic and visual information provide an objective tool for evaluating surgical skills. Objective evidence for a learning curve suggests that surgical residents acquire a major portion of their laparoscopic skill between year 1 and year 3 of training.}, contents = {161} } @article{BRL152, author = {R. Adams and D. Klowden and B. Hannaford}, title = {Virtual Training for a Manual Assembly Task}, journal = {Haptics-e, the electronic journal of haptics research}, volume = {2}, number = {2}, month = {17-Oct-}, year = {2001}, annote = {http://www.haptics-e.org/Vol\_02/he-v2n2.pdf}, abstract = {This paper describes an experiment conducted to investigate the benefits of force feedback for virtual reality training. Three groups of subjects received different levels of training before completing a manual task, the construction of a LEGO(tm) biplane model. One group trained on a Virtual Building Block (VBB) simulation which emulates the real task in a virtual environment, including haptic feedback. A second group also trained on the VBB system, but without the force feeback. The last group received no virtual reality training. Completion times for these different groups in building the actual biplane model in the real world were compared.}, contents = {152} } @article{BRL151, author = {B. Hannaford and J.H. Ryu}, title = {Time Domain Passivity Control of Haptic Interfaces}, journal = {IEEE Transactions on Robotics and Automation}, volume = {18}, number = {1}, pages = {1-10}, month = feb, year = {2002}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep151.pdf}, abstract = {A patent pending, energy based, method is presented for controlling a haptic interface system to ensure stable contract under a wide variety of operating conditions. System stability is analyzed in terms of the time -- domain definition of passivity. We define a "Passivity Observer" (PO) which measures energy flow in and out of one or more subsystems in real-time software. Active behavior is indicated by a negative value of the PO at any time. $<$p$>$ We also define the "Passivity Controller" (PC), an adaptive dissipative element which, at each time sample, absorbs exactly the net energy output (if any) measured by the PO. The method is tested with simulation and implementation in the "Excalibur" haptic interface system. Totally stable operation was achieved under conditions such as stiffness $>$ 100 N/mm or time delays of 15ms. The PO/PC method requires very little additional computation and does not require a dynamical model to be identified.}, contents = {151} } @inproceedings{BRL150, author = {B. Hannaford and G. Klute and K. Jaax}, title = {Bio-inspired Actuation and Sensing}, booktitle = {Autonomous Robots (Special Issue, Papers from the JPL workshop on Biomorphic Robotics, August 2000)}, pages = {267-272}, publisher = {Kluwer Academic Publishers}, address = {Boston/Dordrecht/London}, month = nov, year = {2001}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep150.pdf}, abstract = {The superb ability of animals to negotiate rough terrain has caused engineers to focus on mechanical properties of muscle and other unique features in order to design improved robots for exploration. This paper reviews recent work in artificial muscle actuators, as well as a new sensor based on a robotic model of the muscle spindle cell. The actuator contains a pneumatic force generator in parallel with a non-linear damping element and in series with a non-linear elastic "tendon". Work loop experiments were performed to characterize this actuator under conditions similar to real locomotion at different speeds. The robotic muscle spindle is an 8x1 cm device which simulates the response of the physiological muscle spindle to stretch. Its non-linear properties are thought to contribute to stable accurate control over a wide range of motion.}, note = {Published as Autonomous Robots (Special Issue, Papers from the JPL workshop on Biomorphic Robotics, August 2000), volume 11, number 3}, contents = {150} } @article{BRL149, author = {K. Jaax and B. Hannaford}, title = {A Biorobotic Structural Model of the Mammalian Muscle Spindle Primary Afferent Response}, journal = {Annals of Biomedical Engineering}, volume = {30}, number = {1}, pages = {84-96}, month = jan, year = {2002}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep149.pdf}, abstract = {A biorobotic model of the mammalian muscle spindle Ia response was implemented in precision hardware. We derived engineering specifications from displacement, receptor potential and Ia data in the muscle spindle literature, allowing reproduction of muscle spindle behavior directly in the robot s hardware; a linear actuator replicated intrafusal contractile behavior, a cantilever-based transducer reproduced sensory membrane depolarization, and a voltage-controlled oscillator encoded strain into a frequency signal. Aspects of muscle spindle behavior not intrinsic to the physical design were added in control software using an adaptation of Schaafsma s mathematical model. We tuned the response to biological ramp and hold metrics including peak, mean, dynamic index, time domain response and sensory region displacement. The model was validated against biological Ia response to ramp and hold, sinusoidal and fusimotor inputs. The response with dynamic or static gamma motorneuron input was excellent across all studies. The passive spindle response matched well in 5 of the 9 measures. Potential applications include basic science muscle spindle research and applied research in prosthetics and robotics. $<$p$>$ Key Terms: Biomimetics, Mechanoreceptor, Ia, Gamma Motorneuron, Dynamic Index, Fusimotor}, contents = {149} } @article{BRL146, author = {R. Adams and B. Hannaford}, title = {Control Law Design for Haptic Interfaces to Virtual Reality}, journal = {IEEE Trans. Control Systems Technology}, volume = {10}, number = {1}, pages = {3-13}, month = jan, year = {2002}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep146.pdf}, abstract = {The goal of control law design for haptic displays is to provide a safe and stable user interface while maximizing the operator� sense of kinesthetic immersion in a virtual environment. This paper outlines a control design approach which guarantees the stability of a haptic interface when coupled to a broad class of human operators and virtual environments. Two-port absolute stability criteria are used to develop explicit control law design bounds for three different haptic display implementations: the basic impedance display, the impedance display with force compensation, and the admittance display. The strengths and weaknesses of each approach are illustrated through numerical and experimental results for a three degree-of-freedom device. The example highlights the ability of the proposed design procedure to handle some of the more difficult problems in control law synthesis for haptics, including structural flexibility and non-collocation of sensors and actuators.}, contents = {146} } @article{BRL143, author = {S. Venema and B. Hannaford}, title = {A Probabilistic Representation of Human Workspace for Use in the Design of Human Interface Mechanisms}, journal = {IEEE Trans. Mechatronics}, volume = {6}, number = {3}, pages = {286-294}, year = {2001}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep143.pdf}, abstract = {In designing kinematic mechanisms such as haptics devices for human usability, we must carefully consider human motion range. However, size variation across the human population significantly complicates anthropocentric design analysis. In this paper we develop a probabilistic representation for mechanism reachable workspace which is based on a kinematic model containing stochastically defined parameters. Using anthropometric data, we show how this "stochastic reachable workspace" may be derived, and present a case study for the human finger. This representation of human reachable workspace may then be used to more accurately design human interface mechanisms which accomodate a wide variety of users. The results of our case study on the reachable workspace of the human finger wer used in the design of a fingertip haptic display. $<$p$>$ Index terms: Anthropocentric mechanism design, ergonomics, stochasitic reachable workspace.}, contents = {143} } @article{BRL142, author = {J. Rosen and B. Hannaford and C. Richards and M. Sinanan}, title = {Markov Modeling of Minimally Invasive Surgery Based on Tool/Tissue Interaction and Force/Torque Signatures for Evaluating Surgical Skills}, journal = {IEEE Transactions on Biomedical Engineering}, volume = {48}, number = {5}, pages = {579-591}, month = may, year = {2001}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep142.pdf}, abstract = {The best method of training for laparoscopic surgical skills is controversial. Some advocate observation in the operating room, while others promote animal and simulated models or a combination of surgery-related tasks. A crucial process in surgical education is to evaluate the level of surgical skills. For laparoscopic surgery, skill evaluation is traditionally performed subjectively by experts grading a video of a procedure performed by a student. By its nature, this process uses fuzzy criteria. The objective of the current study was to develop and assess a skill scale using Markov Models (MM). Ten surgeons (5 Novice Surgeons - NS; 5 Expert Surgeons - ES) performed a cholecystectomy and Nissen fundoplication in a porcine model. An instrumented laparoscopic grasper equiped with a three-axis force/torque sensor was used to measure the forces/torques (F/T) at the hand/tool interface synchronized with a video of the tool operative maneuvers. A synthesis of frame-by-frame video analysis and a vector quantization algorithm, allowed to define force/torque signatues associated with}, contents = {142} } @article{BRL133, author = {C. Richards and J. Rosen and B. Hannaford and M. MacFarlane and C. Pellegrini and M. Sinanan}, title = {Skills Evaluation in Minimally Invasive Surgery Using Force/Torque Signatures}, journal = {Surgical Endoscopy}, volume = {14}, number = {9}, pages = {791-798}, year = {2000}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep133.pdf}, abstract = {Background: One of the more difficult tasks in surgical education is to teach the optimal application of instrument forces and torques necessary to facilitate the conduct of an operation. For laparoscopic surgery, such training has traditionally taken place in the operating room, reducing operating room efficiency and potentially affecting the safe conduct of the operation. Objective: The objective of the current study was to measure and compare forces and torque signatures at the tool/hand interface generated during laparoscopic surgery by novice (NS) and experienced (ES) surgeons using a novel force-torque laparoscopic instrument. Methods: Four surgeons (2-NS, 2-ES) performed a cholecystectomy and Nissen fundoplication in a porcine model. An instrumented laparoscopic grasper with interchangeable standard surgical tips equipped with a three-axis force/torque sensor was used to measure the force/torque signature at the hand/tool interface. Force/torque data synchronized with visual view of the tool operative maneuvers were collected simultaneously via a novel graphic user interface incorporated picture-in-picture video technology. Subsequent frame by frame, video analysis of the operation allowed to define states within each step of the operation. Forces and torques measured within each state were further analyzed using vector quantization and the hidden Markov statistical model. Results: The NS group used a mean of 138\% greater force and 130\% greater torque during all stages of an operation compared to the ES group. Furthermore, the completion time of a laparoscopic cholecystectomy on a porcine model was 270\% greater in the NS group. State analysis suggests that the majority of this time was consumed in an "idle" without useful contribution to the conduct of the operation. Conclusions: Preliminary data suggest that force/torque signatures provide an objective means of distinguishing novice from skilled surgeons. Clinical force/torque sigy may be helpful in both training and measuring technical proficiency during laparoscopic surgery.}, contents = {133} } @article{BRL132, author = {S.C. Venema and B. Hannaford}, title = {Experiments in Fingertip Perception of Surface Discontinuities}, journal = {Intl. Journal of Robotics Research}, volume = {19}, number = {7}, pages = {684-696}, month = jul, year = {2000}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep132.pdf}, abstract = {In this paper, we present the results of experiments that explore the ability of the human fingertip to detect haptically simulated first-order and second-order surface discontinuities. A single finger, planar motion fingertip haptic display (FHD) developed at the University of Washington was used by multiple test operators to kinesthetically trace haptically simulated surfaces under a variety of treatment conditions. Experiment variables included the magnitude and type of discontinuity, as well as the stiffness and damping terms used in the haptic simulation algorithm. Test operators were asked to haptically locate a discontinuity on a simulated surface for each treatment condition with the location accuracy being used as the experiment performance metric. The results reveal how the surface discontinunity detection ability is degraded by control gains that are either too low or too high, indicating that a given haptic simulation system may have an optimum set of control gains that will yield the best performance for this type of task.}, contents = {132} } @article{BRL131, author = {G.K. Klute and B. Hannaford}, title = {Accounting for Elastic Energy Storage in McKibben Artificial Muscle Actuators}, journal = {ASME Journal of Dynamic Systems, Measurements, and Control}, volume = {122}, number = {2}, pages = {386-388}, month = jun, year = {2000}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep131.pdf}, abstract = {The McKibben artificial muscle is a pneumatic actuator whose properties include a very high force to weight ratio. This characteristic makes it very attractive for a wide range of applications such as mobile robots and prosthetic appliances for the disabled. In this paper, after reviewing previous attempts at modeling, we present a model that includes a non-linear, Mooney-Rivlin mathematical description of the actuators internal bladder. Experimental results show that the model provides significant improvement in the ability to predict output force as a function of input pressure and actuator length. However, a discrepancy between model and experiment, albeit smaller than previous models, still exists. A number of frictional factors may be responsible for this discrepancy, which we empirically model as a function of pressure. The end result is a model that incorporates properties of the actuator's exterior braid kinematics, interior bladder materials, and an empirical component describing lumped frictional effects that accurately predicts performance (r2$<$0.96) for actuators of three different sizes.}, contents = {131} } @article{BRL122, author = {J. Rosen and B. Hannaford and M. MacFarlane and M. Sinanan}, title = {Force Controlled and Teleoperated Endoscopic Grasper for Minimally Invasive Surgery - Experimental Performance Evaluation}, journal = {IEEE Transactions on Biomedical Engineering}, volume = {46}, number = {10}, pages = {1212-1221}, month = oct, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep122.pdf}, abstract = {Minimally Invasive Surgery (MIS) generates new user interfaces which create visual and haptic distortion when compared to traditional surgery. In order to regain the tactile and kinesthetic information that is lost, a computerized Force Feedback Endoscopic surgical Grasper (FREG) was developed with computer control and a haptic user interface. The system uses standard unmodified grasper shafts and tips. The FREG can control grasping forces either by surgeon teleoperation control, or under software control. The FREG performance was evaluated using an automated palpation function (programmed series of compressions) in which the grasper measures mechanical properties of the grasped materials. The material parameters obtained from measurements showed the ability of the FREG to discriminate between different types of normal soft tissues (small bowel, lung, spleen, liver, colon and stomach) and different kinds of artificial soft tissue replication materials (latex/Silicone) for simulation purposes. In addition, subjective tests of ranking stiffness of silicone materials using the FREG teleoperation mode showed significant improvement in the performance compared to the standard endoscopic grasper. Moreover, the FREG performance was closer to the performance of the human hand than the standard endoscopic grasper. The FREG as a tool incorporating the force feedback teleoperation technology may provide the basis for application in telesurgery, clinical endoscopic surgery, surgical training, and research.}, contents = {122} } @article{BRL121, author = {M. MacFarlane and J. Rosen and B. Hannaford and C. Pellegrini and M. Sinanan}, title = {Force Feedback Grasper Helps Restore the Sense of Touch in Minimally Invasive Surgery.}, journal = {Journal of Gastrointestinal Surgery}, volume = {3}, number = {3}, pages = {278-285}, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep121.pdf}, abstract = {The age of Minimally Invasive Surgery (MIS) has brought forth astounding changes in the health care field. Less pain and quicker patient recovery have been demonstrated with several types of operations that were once performed by an open technique. With these changes have come reports of complications. The decreased sense of touch is just one of several limitations inherent to current techniques of MIS that limit detection of subtle or unapparent lesions on palpation, such as common duct stones and liver lesions. The purpose of this study is to demonstrate the ability of a force feedback equipped grasper to restore some of the lost sense of touch in MIS. $<$p$>$ To demonstrate this ability, we created six silicone phantoms of identical dimensions but graded compliance, and asked 10 subjects to place them in increasing/decreasing order of compliance. They used three tools (their dominant gloved hand, a standard laparoscopic babcock grasper and our force feedback device fitted with the identical babcock grasper) to rate the compliance of the samples in a blinded fashion. These conditions thus approximated the conditions of open surgery, MIS, and MIS fitted with a force-sensing device, in terms of palpating tissues. Five MIS skilled surgeons and five non-surgeons participated in the study. The results indicate that the force feedback device is significantly (P$<$0.05) better than a standard babcock grasper at rating tissue compliance, but was not as successful as a gloved hand (mean of squared errors = 1.06; 3.15; 0.25 respectively). There was no significant difference between surgeons and non-surgeons in rating compliance. $<$p$>$ We conclude that this force feedback instrument is able to partially restore the sense of touch in MIS. This restored ability may thus potentially result in more efficient operations with improved diagnostic capabilities and fewer complications during MIS.$<$p$>$ Key words: Haptics; Surgical simulation; Force feedback, Touch}, contents = {121} } @article{BRL120, author = {R. J. Adams and B. Hannaford}, title = {Stable Haptic Interaction with Virtual Environments}, journal = {IEEE Transactions on Robotics and Automation}, volume = {15(3)}, pages = {465-74}, month = jan, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep120.pdf}, abstract = {A haptic interface is a kinesthetic link between a human operator and a virtual environment. This paper addresses fundamental stability and performance issues associated with haptic interaction. It generalizes and extends the concept of a virtual coupling network, an artificial link between the haptic display and a virtual world, to include both the impedance and admittance models of haptic interaction. A benchmark example exposes an important duality between these two cases. Linear circuit theory is used to develop necessary and sufficient conditions for the stability of a haptic simulation, assuming the human operator and virtual environment are passive. These equations lead to an explicit design procedure for virtual coupling networks which give maximum performance while guaranteeing stability. By decoupling the haptic display control problem from the design of virtual environments, the use of a virtual coupling network frees the developer of haptic-enabled virtual reality models from issues of mechanical stability.}, contents = {120} } @article{BRL112, author = {P. Buttolo and R. Oboe and B. Hannaford}, title = {Architectures for Shared Haptic Virtual Environments}, journal = {Computers and Graphics}, volume = {21}, number = {4}, pages = {421-9}, month = {July-Aug}, year = {1997}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep112.pdf}, abstract = {The lack of force feedback in visual-only simulations may seriously hamper user proprioception, effectiveness and sense of immersion while manipulating virtual environments. Haptic rendering, the process of feeding back force to the user in response to interaction with the environment is sensitive to delay and can become unstable. In this paper, we describe various techniques to integrate force feedback in shared virtual simulations, dealing with significant and unpredictable delays. Three different implementations are investigated: static, collaborative and cooperative haptic virtual environments.}, contents = {112} } @article{BRL109, author = {F. Boe and B. Hannaford}, title = {On-line Improvement of Speed and Tracking Performance on Repetetive Paths}, journal = {IEEE Transactions on Control Systems Technology}, volume = {6}, number = {3}, pages = {350-358}, month = may, year = {1998}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep109.pdf}, abstract = {When a mechanism such as a robot executes a trajectory, the tracking error increases as the trajectory speed is increased. This paper reports the experimental evaluation of an algorithm which locally adjusts the speed of a repetitive trajectory to achieve a specified level of tracking error. In regions of the trajectory where error is too high, the trajectory is slowed down, in regions where the error is below the specification, the trajectory is speeded up. The algorithm was experimentally evaluated on a 5-axis mini direct drive robot and it stably converged to a satisfactory trajectory for a range of error levels and speeds in spite of wide variations in the key algorithm parameters. The method is independent of the splining method used to generate the trajectory and of the feedback control law, and no model of the system is required.}, contents = {109} } @article{BRL106, author = {C.P. Chou and B. Hannaford}, title = {Study of Human Forearm Posture Maintenance with a Physiologically Based Robotic Arm and Spinal Level Neural Controller}, journal = {Biological Cybernetics}, volume = {76}, pages = {285-298}, year = {1997}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep106.html}, abstract = {The goals of this research are: 1) to apply knowledge of human neuro-musculo-skeletal motion control to a biomechanically designed, neural controlled, "anthroform" robotic arm system, 2) to demonstrate that such a system is capable of responses that match those of the human arm reasonably well in comparable experiments and 3) to utilize the anthroform arm system to study some controversial issues and to predict new phenomena of the human motion control system. A physiologically analogous artificial neural network controller and an anatomically accurate robotic testing elbow are applied in this study. In order to build the physical elbow system to have mechanical properties as close as possible to the human arm, McKibben pneumatic artificial muscles, force sensors, and mechanical muscle spindles are integrated in the system with anatomically accurate muscle attachment points. A physiologically analogous, artificial neural network controller is used to emulate the behavior of spinal segmental reflex circuitry.}, contents = {106} } @article{BRL105, author = {D.Y. Hwang and B. Hannaford}, title = {Teleoperation Performance with a Kinematically Redundant Slave Robot}, journal = {International Journal of Robotics Research}, volume = {17}, number = {6}, pages = {579-597}, month = jun, year = {1998}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep105.pdf}, abstract = {This paper studies the effects of three methods of kinematic redundancy resolution on teleoperation performance with a redundant slave robot in telemanipulation. First, we derived three kinematic redundancy control modes expressing different trade-offs between kinetic energy level, joint usage, and joint limit avoiding. To validate our algorithms we performed simulations, autonomous robot tests, and teleoperation experiments. The trade-off between kinetic energy level and joint limit index was clearly shown in the autonomous test. For teleoperation, 4 tasks and 7 indices were defined. A 3 dof pen-based master and 5 dof mini-direct-drive robot were used with position to position control in Cartesian space. Tasks were x, y, and z positioning and contact force control giving 2 dof kinematic redundancy in the slave robot. Overall, the inertia-weighted pseudo-inverse, proposed by Whitney in 1969, showed best performance, while the least square mode (using no inertial information) showed the worst performance.}, contents = {105} } @article{BRL104, author = {N.E. Greivell and B. Hannaford}, title = {The Design of a Ferrofluid Magnetic Pipette}, journal = {IEEE Transactions on Biomedical Engineering}, volume = {44}, number = {3}, pages = {129-135}, month = mar, year = {1997}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep104.pdf}, abstract = {An electromagnetic pipet using a ferrofluid was designed to sample liquid volumes smaller than 0.2 microliter. Submicroliter sample sizes are desirable for reducing the amount of costly reagents and reducing sample requirement for large-scale analysis. The pipet consists of four electromagnets arranged such that air-gaps are aligned to accommodate a tube. A light-hydrocarbon-based ferrofluid is contained in the tube and acts as a plunger. The position of the ferrofluid in the tube was controlled to within 0.2 mm by combining adjacent air-gap magnetic fields. The position of the ferrofluid as a function of time and magnetic pressure as a function of position was measured in one electromagnet air-gap from the device. Maximum pressure measured was 770 Pascals which corresponds to a maximum velocity of 0.9 cm/s. The assembled pipet weighs approximately 25 grams and it measures 4 cm long, 1 cm wide, and 3 cm high.}, contents = {104} } @article{BRL095, author = {B. Hannaford and K. Kuhn}, title = {A "Hands-On" Course in Consumer Electronics Design}, journal = {International Journal of Mechatronics: Special Issue on Mechatronics Education}, volume = {5}, number = {7}, pages = {753-762}, month = oct, year = {1995}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep095.pdf}, abstract = {There is still a large gap between the academic design approach taught to our students and the real world of competitive product design. In spite of program upgrades which heavily emphasize design, the termination of many of our students' advanced design projects is still a maze of breadboards connected together with wires which randomly wander off to input sensors or output displays. Clearly, there is a big step missing between the disorganized connection of components which concludes a design project, and the sleek, injection molded, Sony Discman that is playing in the design laboratory beside the workbench. In an effort to close the gap between engineering education and modern consumer electronics product design, the Department of Electrical Engineering at the University of Washington has initiated a "reverse-engineering" course in Consumer Electronics. The first offering of the course was made during Winter 1994 as part of the College of Engineering honors program.}, contents = {095} } @article{BRL093, author = {B. Hannaford and P.H. Marbot and P. Buttolo and M. Moreyra and S. Venema}, title = {Scaling Properties of Direct Drive Serial Arms}, journal = {International Journal of Robotics Research}, volume = {15}, number = {5}, pages = {459-472}, year = {1996}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep093.pdf}, abstract = {This paper studies the ways that the performance of direct drive serial robots changes as system size is changed. We are particularly interested in the physical laws for scaling down direct drive arms to small sizes. Using theoretical scaling analysis, we show that there is a net physical performance advantage to small direct drive arms. A key factor for direct drive robot performance is the torque to mass ratio of the actuators, U. We show how U varies with the scale of DD actuators, and we also calculate how the dynamic performance varies with scale. We compare our calculations with experimental measurements of actuators of various sizes taken from small hard disk drives and compare them with published data for larger motors. Finally, we describe a prototype, 5-axis, direct drive, serial arm having a reach of 10cm and a workvolume of about 136cm3. Some potential applications are briefly discussed.}, contents = {093} } @article{BRL091, author = {B. Hannaford and J.M. Winters and C.P. Chou and P.H. Marbot}, title = {The Anthroform Arm: {A} System for the Study of Spinal Circuits}, journal = {Annals of Biomedical Engineering: L. Stark Special Issue}, volume = {23}, number = {4}, pages = {399-408}, month = mar, year = {1995}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep091.pdf}, abstract = {This paper reports the design, construction, and testing of a replica of the human arm which aims to be dynamically accurate as well as kinematically accurate. The arm model is actuated with McKibben pneumatic artificial muscles, and controlled by a special purpose digital signal processing system designed to simulate spinal neural networks in real time. An artificial muscle spindle has also been designed and tested. Design and test data are reviewed, and the paper describes how we hope to use the system to improve our understanding of the reflexive control of human movement and posture.}, contents = {091} } @article{BRL083, author = {P. Bhatti and B. Hannaford}, title = {Single Chip Optical Encoder Based Velocity Measurement System}, journal = {IEEE Transactions on Control Systems Technology}, volume = {5}, number = {6}, pages = {654-61}, month = nov, year = {1997}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep083.pdf}, abstract = {A single chip system is designed, implemented, tested and analyzed for the measurement of velocity from incremental optical encoders with quadrature outputs. The system uses a field programmable gate array (FPGA) chip to take advantage of high flexibility and a low cost design cycle. The device uses two counting methods: period counting for low velocities and frequency counting for high velocities to obtain high resolution measurements for a wide range of velocities with a fixed 16bit word length. Verification testing of the device was consistent with the error analysis and showed that quantization errors can be made arbitrarily small by adjusting the trade-off between velocity range and minimum resolution. This trade-off can be adjusted by the designer by simple modifications to the basic design.}, contents = {083} } @article{BRL080, author = {C.P. Chou and B. Hannaford}, title = {Measurement and Modeling of McKibben Pneumatic Artificial Muscles}, journal = {IEEE Transactions on Robotics and Automation}, volume = {12}, number = {1}, pages = {90-102}, month = feb, year = {1996}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Chou080.html}, abstract = {This paper reports mechanical testing and modeling results for the McKibben artificial muscle pneumatic actuator. This device, first developed in the 1950's, contains an expanding tube surrounded by braided cords. We report static and dynamic length-tension testing results and derive a linearized model of these properties for three different models. The results are briefly compared with human muscle properties to evaluate the suitability of McKibben actuators for human muscle emulation in biologically based robot arms.}, contents = {080} } @misc{BRL999, author = {{XXX}}, title = {{YYY}}, institution = {XXX}, year = {ZZZ}, contents = {999} } @misc{BRL999, author = {{XXX}}, title = {{YYY}}, institution = {XXX}, year = {ZZZ}, contents = {999} } @inproceedings{BRL243, author = {F. Rydén and H. J. Chizeck and S. Nia Kosari and H. King and B. Hannaford}, title = {Using Kinect and a Haptic Interface for Implementation of Real-Time Virtual Fixture}, booktitle = {Robotics Sciences and Systems, Workshop on RGB-D: Advanced Reasoning with Depth Cameras,}, address = {Los Angeles,}, month = jun, year = {2011}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep243.pdf}, abstract = {The use of haptic virtual fixtures is a potential tool to improve the safety of robotic and telerobotic surgery. They can “push back” on the surgeon to prevent unintended surgical tool movements into protected zones. Previous work has suggested generating virtual fixtures from preoperative images like CT scans. However these are difficult to establish and register in dynamic environments. This paper demonstrates automatic generation of real-time haptic virtual fixtures using a low cost Xbox KinectTMdepth camera connected to a virtual environment. This allows generation of virtual fixtures and calculation of haptic forces, which are then passed on to a haptic device. This paper demonstrates that haptic forces can be successfully rendered from real-time environments containing both non-moving and moving objects. This approach has the potential to generate virtual fixtures from the patient in real-time during robotic surgery.}, contents = {243} } @inproceedings{BRL242, author = {F. Ryden and S. Nia Kosari and H. Chizeck}, title = {Proxy Method for Fast Haptic Rendering from Time Varying Point Clouds}, booktitle = {Proceedings IROS 2011, San Francisco}, month = mar, year = {2011}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep242.pdf}, abstract = {Abstract—This paper proposes a novel algorithm for haptic rendering from time varying point clouds captured using an Xbox Kinect RGB-D camera. Existing methods for point-based haptic rendering using a proxy can not directly be applied since no information about the underlying objects is given. This paper extends the notion of proxy to point clouds. The resulting haptic algorithm can successfully render haptic forces from point clouds captured in real-time representing both static and dynamic objects.}, contents = {242} } @inproceedings{BRL241, author = {K. Haller and B. Hannaford}, title = {Haptic Exploration of Spheres: Anatomical Regions used for Perception}, booktitle = {Proceedings, IEEE World Congress on Haptics}, address = {Instanbul Turkey}, month = jan, year = {2011}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep241.pdf}, abstract = {Humans can perceive differences in sphericity of objects in the hand within a certain error margin. Subjects can detect sphericity based on geometry, texture, and other physical cues. The part of the hand used to distinguish a perfect sphere from a distorted on is examined in this paper. In this experiment subjects were asked to discern a perfect steel ball bearing from a distorted one without visual cues. During the final discrimination task subjects were given a pair of spheres coated in ink, staining their hands where they touched the ball bearings. Photographs were taken of the ink- stained hands and analyzed with a grid based on anatomical features. The parts of the hand most commonly used among all subjects were the thumb and the area spanning the index and middle finger. These regions had an average ink coverage of between 81 and 100 percent, much higher values than the rest of the hand.}, contents = {241} } @inproceedings{BRL240, author = {R.J. Adams and A.B. Olowin and B. Hannaford and O.S. Sands}, title = {Tactile Data Entry for Extravehicular Activity}, booktitle = {Proceedings, IEEE World Congress on Haptics}, address = {Instanbul Turkey}, month = jan, year = {2011}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep240.pdf}, abstract = {In the task-saturated environment of extravehicular activity (EVA), an astronaut’s ability to leverage suit-integrated information systems is limited by a lack of options for data entry. In particular, bulky gloves inhibit the ability to interact with standard computing interfaces such as a mouse or keyboard. This paper presents the results of a preliminary investigation into a system that permits the space suit gloves themselves to be used as data entry devices. Hand motion tracking is combined with simple finger gesture recognition to enable use of a virtual keyboard, while tactile feedback provides touch-based context to the graphical user interface (GUI) and positive confirmation of keystroke events. In human subject trials, conducted with twenty participants using a prototype system, participants entered text significantly faster with tactile feedback than without (p = 0.02). The results support incorporation of vibrotactile information in a future system that will enable full touch typing and general mouse interactions using instrumented EVA gloves.}, contents = {240} } @inproceedings{BRL239, author = {P. Buckley and H. Hawkeye King and M. Wang and B. Hannaford}, title = {Effects of Thermal Protection Methods on Haptic Perception}, booktitle = {Proceedings, IEEE World Congress on Haptics}, address = {Instanbul Turkey}, month = jan, year = {2011}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep239.pdf}, abstract = {Electric DC motors that convert electric current to torque are the most common type of actuators used in haptic interfaces. However, high currents necessary to deliver large haptic forces can generate heat in the electromagnetic coils, and in the extreme can cause malfunctions due to overheating. It is therefore necessary to add ther- mal protection mechanisms to limit the output current. While this is a common feature of haptic devices it is not clear what makes a superior current limiting method or what effect such limits have on haptic psychophysical thresholds, task performance using haptics, or the subjective experience of haptic realism. The current work evaluates three methods for current limiting: limit output to zero, limit output to a safe steady-state current, limit output current in linear proportion to temperature. Using both quantitative and qualitative metrics, these are compared to a control case with no current limit. Human subjects use one finger of a multifinger haptic device to perform a psychophysical thresholding ex- periment designed to measure human perception of small haptic effects, while forcing the device to heat up. All methods are shown to effectively regulate temperature and show no statistically significant difference in psychophysical threshold value. Users show a slight preference for the linear method, while the zero output method requires less time spent interacting with current limited conditions.}, contents = {239} } @inproceedings{BRL232, author = {H. Hawkeye King and Blake Hannaford and Ka-Wai Kwok and Guang-Zhong Yang and Paul Griffiths and Allison Okamura and Ildar Farkhatdinov and Jee-Hwan Ryu and Ganesh Sankaranarayanan and Venkata Arikatla and Kotaro Tadano and Kenji Kawashima and Angelika Peer and Thomas Schau and Martin Buss and Levi Miller and Daniel Glozman and Jacob Rosen and Thomas Low}, title = {Plugfest 2009: Global Interoperability in Telerobotics and Telemedicine}, booktitle = {International Conference on Robotics and Automation, ICRA 2010}, month = may, year = {2010}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep232.pdf}, abstract = {Despite the great diversity of teleoperator designs and applications, their underlying control systems have many similarities. These similarities can be exploited to enable interoperability between heterogeneous systems. We have developed a network data specification that can be used for Internet based control of a wide range of teleoperators. $<$p$>$ In this work we explore Internet based interoperable telerobotics, focusing on the telesurgery application domain. Fourteen globally dispersed telerobotic master and slave systems were connected in thirty trials in one twenty four hour period. Users performed common manipulation tasks to demonstrate effective master-slave operation. With twenty eight (93\%) successful, unique connections the results show a high potential for standardizing telerobotic operation. Furthermore, new paradigms for telesurgical operation and training are presented, including a networked surgery trainer and exoskeleton control of micro-manipulators.}, contents = {232} } @inproceedings{BRL231, author = {B. Hannaford and J. Dosher and S. Venkatachalam}, title = {Haptic Exploration of Spheres: Techniques and Initial Experiments}, booktitle = {North American Haptics Symposium 2010}, month = mar, year = {2010}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep231.pdf}, abstract = {Haptic perception of properties of objects in the hand is not fully understood. One aspect is the precision with which subjects can detect geometrical features. In this experiment, subjects discriminated between pairs of steel spheres in which one was a precisely manufactured ball bearing and the other was distorted by various degrees. Precise distortions of spheres provide a very sensitive but practical way to create controlled experiments. In one experiment, we reduced the diameter along a single axis and smoothed and polished the resulting shape. In another, the reduced diameter was held constant, and local curvature was varied. Using these spheres, subjects were able to detect subtle changes in sphere diameter along one axis, but were not as sensitive to changes in local curvature. For diameter, a just-noticable-difference (JND) between 2$\backslash$\% and 5$\backslash$\% was measured.}, contents = {231} } @inproceedings{BRL230, author = {B. Redmond and R. Aina and T. Gorti and B. Hannaford}, title = {Haptic Characteristics of some Activities of Daily Living}, booktitle = {North American Haptics Symposium 2010}, month = mar, year = {2010}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep230.pdf}, abstract = {Activities of daily living (ADLs) are of interest in rehabilitation, independent living for the elderly and infirm, and to the designers of everyday objects. This paper reports measurements of forces and torques at the interaction point between users and some everyday objects in ADLs. We report force and torque recordings of several writing tasks with pen and pencil, opening and closing a jar, and dialing and texting with a cell phone. Besides average measurements, we measured some statistically significant differences between some very similar activities. For example, RMS forces in writing tasks were lower with pencil than ball-point pen, dialing a number showed lower forces than texting, and texting forces differed between ``ABC" and ``T9" texting methods.}, contents = {230} } @inproceedings{BRL229, author = {H.H. King and B. Hannaford and J. Kammerl and E. Steinbach}, title = {Establishing Multimodal Telepresense Sessions using the Session Initiation Protocol ({SIP}) and Advanced Haptic Codecs}, booktitle = {Proceedings of North American Haptics Symposium 2010}, month = mar, year = {2010}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep229.pdf}, abstract = {In telepresence and telemanipulation systems, multimodal data is exchanged over a network allowing humans to experience and to operate in remote or inaccessible environments. To operate over the global Internet and connect to multiple telepresence systems, a exible framework for initiating, handling and terminating Internet-based telerobotic sessions becomes necessary. In this work, we explore the use of standard Internet session and transport protocols in the context of telerobotic applications. Session Initiation Protocol (SIP) is widely used to handle multimedia teleconference sessions with audio, video or text, and provides many services advantageous for establishing connections between heterogeneous haptic interfaces and telerobotic systems. We apply the session paradigm to the creation and negotiation of haptic telepresence sessions and propose to extend this framework to work with the haptic modality. The notion of a haptic codec is introduced for transforming haptic data into a common format, applying data reduction or compression techniques and implementing teleoperation control architectures. The use of the Real- Time Transport Protocol (RTP) is explored for transport of teleoperation data. Finally, a prototype and demonstrator system is presented for evaluation of the proposed framework.}, contents = {229} } @inproceedings{BRL228, author = {H.H. King and R. Donlin and B. Hannaford}, title = {Haptic Thresholds for Single vs. Multi-Finger Icons}, booktitle = {Proceedings of North American Haptics Symposium 2010}, month = mar, year = {2010}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep228.pdf}, abstract = {This paper presents experiments measuring psychophysical thresholds for multi-finger single point interaction with small haptic effects. Subjects used the UW Multi-Finger Haptic Display to interact with small haptic icons in a virtual environment. A forcedchoice adaptive thresholding method is used to find a minimum detectable force magnitude. First, studies are performed to evaluate the consistency of our test apparatus across the four fingertips and to compare our application of the adaptive thresholding method to the prior work. Next, force detection thresholds for individual fingers are collected and compared to the force detection threshold using four fingers simultaneously. $<$p$>$ The results show comparable force detection levels between index, middle, pinkie and multi-finger interaction (33.5, 32.1, 33.5, 28.9 mN respectively) but less sensitivity with the ring finger (mean threshold of 43.6 mN). Repeated measures analysis of variance and t-tests with Bonferroni correction supports these conclusions. Most importantly, we show that the multi-finger threshold is not significantly lower than the threshold of the individual fingers. The implication for device design is that the relevant multi-finger device parameters are no more stringent than for single finger devices.}, contents = {228} } @inproceedings{BRL227, author = {H.H. King and K. Tadano and R. Donlin and D. Friedman and M.J.H. Lum and V. Asch and C. Wang and K. Kawashima and B. Hannaford}, title = {Preliminary protocol for interoperable telesurgery}, booktitle = {Advanced Robotics, 2009. ICAR 2009. International Conference on}, pages = {1-6,}, month = {22-26 June}, year = {2009}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep227.pdf}, abstract = {In the same way Internet standards have connected heterogeneous computing systems, we predict robot communication standards will speed research and development of teleoperated robots. In this paper, a preliminary specification is presented for interoperability among robotic telesurgery systems. This is a first step towards developing a full telerobotics protocol. One way that interoperability will help is by allowing new teleoperation robots to be compared to existing ones on standard platforms. Using our preliminary specification, two telesurgical masters located in Yokohama, Japan controlled the same surgical assistant robot located in Seattle, WA, USA. Teleoperation was over the public Internet and users performance was measured on a standardized task. The value of the communication standard becomes clear, as a comparison between the two systems exposes several important improvements for the surgical master systems.}, contents = {227} } @inproceedings{BRL226, author = {M.J.H. Lum and J. Rosen and H. H. King and D.W. Friedman and T.S. Lendvay and A. S. Wright and M.N. Sinanan and B. Hannaford}, title = {Teleoperation in Surgical Robotics - Network Latency Effects on Surgical Performance}, booktitle = {Proceedings,31st Annual International Conference of the IEEE EMBS}, address = {Minneapolis, Minnesota, USA}, month = {September 2-6}, year = {2009}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep226.pdf}, abstract = {A teleoperated surgical robotic system allows surgical procedures to be conducted across long distances while utilizing wired and wireless communication with a wide spectrum of performance that may affect the outcome. An open architecture portable surgical robotic system (Raven) was developed for both open and minimally invasive surgery. The system has been the subject of an intensive telesurgical experimental protocol aimed at exploring the boundaries of the system and surgeon performance during a series of field experiments in extreme environments (desert and underwater) teleportation between US, Europe, and Japan as well as lab experiments under synthetic fixed time delay. One standard task (block transfer emulating tissue manipulation) of the Fundamentals of Laparoscopic Surgery (FLS) training kit was used for the experimental protocol. Network characterization indicated a typical time delay in the range of 16-172 ms in field experiments. The results of the lab experiments showed that the completion time of the task as well as the length of the tool tip trajectory significantly increased ( α $<$ 0.02 ) as time delay increased in the range of 0-0.5 sec increased. For teleoperation with a time delay of 0.25s and 0.5s the task completion time was lengthened by a factor of 1.45 and 2.04 with respect to no time delay, whereas the length of the tools’ trajectory was increased by a factor of 1.28 and 1.53 with respect to no time delay. There were no statistical differences between experienced surgeons and non-surgeons in the number of errors (block drooping) as well as the completion time and the tool tip path length at different time delays.}, contents = {226} } @inproceedings{BRL225, author = {E Naerum and H. Hawkeye King and B. Hannaford}, title = {Robustness of the Unscented Kalman Filter for State and Parameter Estimation in an Elastic Transmission}, booktitle = {Proceedings Robotics Science and Systems 2009 (http://www.roboticsproceedings.org)}, address = {Seattle}, month = jul, year = {2009}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep225.pdf}, abstract = {The Unscented Kalman Filter (UKF) was applied to state and parameter estimation of a one degree of freedom robot link with an elastic, cable-driven transmission. Only motor encoder and command torque data was used as input to the filter. The UKF was used offline for joint state and model-parameter estimation, and online for state estimation. This paper presents an analysis of the robustness of the UKF to unknown/unmodeled variation in inertia, cable tension and contact forces, using experimental data collected with the robot. Using model parameters found offline the UKF successfully estimated motor and link angles and velocities online. Although the transmission was very stiff, and hence the motor and link states almost equal, information about the individual states was obtained. Irrespective of variation from nominal conditions the UKF link angle estimate was better than using motor position as an approximation (i.e. inelastic transmission assumption). The angle estimates were particularly robust to variation in operating conditions, velocity estimates less so. A near-linear relationship between contact forces and estimation errors suggested that contact forces might be estimated using this error information. (Best Paper Award Candidate)}, contents = {225} } @inproceedings{BRL224, author = {M.J.H. Lum and J. Rosen and T.S. Lendvay and M.N. Sinanan and B. Hannaford}, title = {Effect of Time Delay on TeleSurgical Performance}, booktitle = {IEEE International Conference on Robotics and Automation (ICRA)}, year = {2009}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep224.pdf}, abstract = {In the area of surgical robotics no standard means of performance evaluation has been established. Thousands of surgeons have gone through the SAGES FLS Program, and the psychomotor skill portion of the program is considered the gold standard in laparoscopic skills evaluation. This research describes the use of the FLS Block Transfer task to evaluate the performance of both surgeons and non-surgeons teleoperating under different time delay conditions on the University of Washington RAVEN Surgical Robot. Time delays of 0ms, 250ms, and 500ms were used and a statistically significant difference in mean block transfer time as well as mean tool tip path length were shown. For this task no significant difference was shown between the surgeon and non-surgeon groups. Clearly surgeon input and feedback is key to surgical robotic system development, but this result implies that non-surgeon subjects can be tested for simple usability evaluations.}, contents = {224} } @inproceedings{BRL221, author = {E. Naerum and B. Hannaford}, title = {Global Transparency Analysis of the Lawrence Teleoperator Architecture}, booktitle = {IEEE International Conference on Robotics and Automation (ICRA)}, pages = {4344-4349}, year = {2009}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep221.pdf}, abstract = {Despite the frequent use of the Lawrence architecture since its introduction in the early 90’s, its global transparency characteristics have not yet been fully analyzed. That is the goal of this paper. We state and prove necessary and sufficient conditions for transparency, with special attention to the information sent across the communication layer. In particular, it is shown that transparency can be preserved even though one, and even two, communication channels are set to zero. The results may serve as a guideline for transparent teleoperator design}, contents = {221} } @inproceedings{BRL218, author = {G. Sankaranarayanan and B. Hannaford}, title = {Experimental Comparison of Internet Haptic Collaboration with Time-Delay Compensation Techniques}, booktitle = {Proceedings, IEEE International Conference on Robotics and Automation (ICRA2008)}, pages = {206-211}, address = {Pasadena, CA}, year = {2008}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep218.pdf}, abstract = {In this paper we analyzed the performance of a peer-to-peer haptic collaboration system with two users jointly manipulating an object with mass and damping properties. We used objective measures to compare tuned PD, wave variables and time domain passivity controllers subject to real time delays from the Internet through similar experimental parameters. We set up a packet reflector network at our collaborators’ servers in order to able to perform the experiment with subjects located in the same laboratory. Subjects were blinded to which controller was used and received them in a randomized sequence. UDP data packets were used for haptic data communication and the packet transmission rate was maintained at 1000 Hz. Our experimental results show that the tuned PD controller gave the best performance in terms of position error and wave variables in terms of force.}, contents = {218} } @inproceedings{BRL216, author = {M.J.H. Lum and D.C.W. Friedman and G. Sankaranarayanan and H. King and A. Wright and M. Sinanan and T. Lendvay and J. Rosen and B. Hannaford}, title = {Objective Assessment of Telesurgical Robot Systems: Telerobotic {FLS}}, booktitle = {Proceedings, Medicine Meets Virtual Reality (MMVR)}, address = {Long Beach, CA}, month = {29-Jan --- 1-Feb}, year = {2008}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep216.pdf}, abstract = {Robotically assisted surgery stands to further revolutionize the medical\par The Society of American Gastrointestinal Endoscopic Surgeons (SAGES) Fundamentals of Laparoscopic Surgery (FLS) program contains curriculum that includes both a cognative and psychomotor skills. In this research the use of FLS Block Transfer task is used to evaluate the performance of surgeons’ teleoperating the University of Washington Surgical robot. The use of the FLS Trainer Box and accessories kit provides a well-defined series of tasks that can be repeated by any researchers working in the field of surgical robotics so that systems can be evaluated using a common method.}, contents = {216} } @inproceedings{BRL215, author = {M.J.H Lum and J. Rosen and H. King and D.C.W. Friedman and G. Donlin and G. Sankaranarayanan and B. Harnett and L. Huffnam and C. Doarn and T. Broderick and B. Hannaford}, title = {Telesurgery Via Unmanned Aerial Vehicle ({UAV}) with a Field Deployable Surgical Robot}, booktitle = {Proceedings, Medicine Meets Virtual Reality (MMVR)}, address = {Long Beach, CA}, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep215.pdf}, abstract = {Robotically assisted surgery stands to further revolutionize the medical field and provide patients with more effective healthcare. Most robotically assisted surgeries are teleoperated from the surgeon console to the patient where both ends of the system are located in the operating room. The challenge of surgical teleoperation across a long distance was already demonstrated through a wired communication network in 2001. New development has shifted towards deploying a surgical robot system in mobile settings and/or extreme environments such as the battlefield or natural disaster areas with surgeons operating wirelessly. As a collaborator in the HAPs/MRT (High Altitude Platform/Mobile Robotic Telesurgery) project, The University of Washington surgical robot was deployed in the desert of Simi Valley, CA for telesurgery experiments on an inanimate model via wireless communication through an Unmanned Aerial Vehicle (UAV). The surgical tasks were performed telerobotically with a maximum time delay between the surgeon’s console (master) and the surgical robot (slave) of 20 ms for the robotic control signals and 200 ms for the video stream. This was our first experiment in the area of Mobile Robotic Telesurgery (MRT). The creation and initial testing of a deployable surgical robot system will facilitate growth in this area eventually leading to future systems saving human lives in disaster areas, on the battlefield or in other remote environments.}, contents = {215} } @inproceedings{BRL214, author = {G. Sankaranarayanan and B. Hannaford}, title = {Comparison of Performance of Virtual Coupling Schemes for Haptic Collaboration using Real and Emulated Internet Connections}, booktitle = {Proceedings of Robocom 2007}, address = {Athens, Greece}, month = oct, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep214.pdf}, abstract = {Networked haptic virtual environments (NHVEs) are those in which multiple users collaborate and experience force feedback at the same time. The robustness of such systems needs to be tested under various network conditions that closely mirror the Internet. Previously, we had proposed three virtual coupling schemes to maintain position coherency in a NHVE, which were tested using constant and then time-varying delays using the actual Internet through UDP packet reflectors. In this paper we present the results of comparing performance of the virtual coupling schemes for a time varying delay emulated using the popular network emulator NIST Net, with delay conditions that existed during our real Internet experiment to Italy. UDP was used for haptic data communication because of the high transmission rate requirements for NHVEs. Experiments were conducted for three fixed packet transmission rates of 1000, 500 and 100 Hz, and their performance compared using an independent-samples t-test to the data obtained using the Internet. Locally, the haptic update rate was maintained at 1000 Hz during the experiments. Our results show that the NIST Net was a suitable emulator for testing with lower packet transmission rates. At the transmission rate of 1000 Hz the performance of the virtual coupling schemes were significantly different from that of the actual Internet experiment.}, contents = {214} } @inproceedings{BRL213, author = {G. Sankaranarayanan and H. King and S.Y. Ko and M.J.H Lum and D.C.W. Friedman and J. Rosen and B. Hannaford}, title = {Portable Surgery Master Station for Mobile Robotic Telesurgery}, booktitle = {Proceedings of Robocom 2007}, address = {Athens, Greece}, month = oct, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep213.pdf}, abstract = {We describe a system that provides a low-cost, portable control station for experimentation in mobile robotic telesurgery. The software and hardware implementation of our system are described in detail. The device mapping between the Haptic Interface Devices (HID) and the surgical robot that enable the surgeon to effectively teleoperate the surgical robot are explained along with our communication protocols for telesurgery. We have also provided our initial results from extensive field testing of our system in different hardware and software configurations and challenging locations. We focus on working under sub-optimal network conditions for field operation in remote environments, and the importance of interoperability and distribution among networked surgical technologies.}, contents = {213} } @inproceedings{BRL212, author = {G. Sankaranarayanan and B. Hannaford}, title = {Experimental Internet Haptic Collaboration Using Virtual Coupling Schemes}, booktitle = {Proceedings 2008 Haptics Symposium}, address = {Reno NV.}, year = {2008}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep212.pdf}, abstract = {In this paper we present the results from several global-scale haptic collaboration experiments that were performed using the Internet for three virtual coupling schemes proposed to maintain position coherency in a networked haptic virtual environment (NHVE). We compared two of our virtual coupling schemes —which represent a peer-to-peer architecture— to the third, with a client-server architecture. We had set up a packet reflector network at our collaborator servers in order to be able to perform the experiments with subjects located within the same laboratory. Our largest one-way latency was in the order of 200 ms for the packet reflector situated in Italy. The virtual coupling parameters were chosen so that it resulted in stable operation for all the delay values that were tested. UDP was used for haptic data communication because of the high transmission rate requirement for NHVEs. There were three experiments carried out in total: two of them at the packet transmission rate of 1000 Hz with a change in the virtual coupling parameters in Scheme 2 and the third one which tested the three virtual coupling schemes at two fixed transmission rates of 500 Hz and 100 Hz. Locally, the haptic update rate was maintained at 1000 Hz during all the experiments. Our results demonstrate that the peer-to-peer virtual coupling schemes can be used for maintaining position coherency in a NHVE. We also show that the position error and the force rendered to the users increase with the reduction in the packet transmission rate. As such, this work could be used for global-scale stable haptic collaboration using the Internet.}, contents = {212} } @inproceedings{BRL211, author = {R. Leuschke and R. Donlin and M. Claus and M. Nugent and D. van der Reyden and B. Hannaford}, title = {Haptic Characteristics of Document Conservation Tasks}, booktitle = {Proceedings 2008 Haptics Symposium}, address = {Reno NV.}, year = {2008 5P 383-386}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep211.pdf}, abstract = {Conservation of historic documents is often necessary to preserve their cultural value for future generations. An important component of the skill of document conservation is delicate hands-on manipulations. As with medical procedural training, there is a great need for better ways to train document conservators in these skills. This paper reports initial measurements of forces and torques at the interaction point between tools and mocked up documents. Five conservators used their preferred tools (such as scalpel, needle, brush, and microspatula) to remove material adhered to the samples. We analyzed video and 100 Hz force and torque recordings in the time and frequency domain to gain understanding of the nature of these tasks. The results can inform design of training simulators for document conservation skills.}, contents = {211} } @inproceedings{BRL210, author = {G. Sankaranarayanan and L. Potter and B. Hannaford}, title = {Measurement and Simulation of Time Varying Packet Delay with Applications to Networked Haptic Virtual Environments}, booktitle = {Proceedings of 1st international Conference on Robot Communication and Coordination (Robocom 2007)}, pages = {1-8}, publisher = {IEEE Press, Piscataway, NJ.}, address = {Athens, Greece}, month = oct, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep210.pdf}, abstract = {Networked haptic virtual environments are increasingly being used in medical simulation, aircraft maintenance training etc. The authors previously proposed virtual coupling schemes for NHVE's and tested it for constant delay simulated by buffers. They are currently working on a time varying delay simulation of the virtual coupling schemes. Here the authors present the implementation of network emulator for such a purpose that can create realistic Internet like networks in a laboratory setting.}, contents = {210} } @inproceedings{BRL209, author = {X. Yu and H.J. Chizeck and B. Hannaford}, title = {Comparison of Transient Performance in the Control of Soft Tissue Grasping}, booktitle = {Proceedings of IROS 2007, San Diego, CA}, pages = {1809-1814}, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep209.pdf}, abstract = {In robot-assisted surgery, surgical tools interact with tissues that have nonlinear mechanical properties. For situations where a pre-specified trajectory of tool positions (or applied forces) is desired, there are many controller designs that might be used. Four candidates are comparatively evaluated here, via computer simulation involving a nonlinear model of soft tissue behavior during grasping actions. The parameters for this model were obtained experimentally (in earlier work). The four candidate controllers are: (1) a welltuned PID controller; (2) feedback linearization in combination with deadbeat control; (3) an optimal open-loop control law obtained via minimization of a quadratic cost function; and (4) a model predictive controller. Simulation trials are used to compare the transient performance of these candidate controllers under different assumptions regarding input and output noises. The conditions where each of the candidates is best are characterized. $<$P$>$Index Terms—Robot-Assisted Surgery, Transient Control, Trajectory Following, Soft Tissue Grasping, PID control, Feedback Linearization, Deadbeat Control, Model Predictive Control.}, contents = {209} } @article{BRL208, author = {R. Leuschke and E.K.T. Kurihara and J. Dosher and B. Hannaford}, title = {High Fidelity Multi Finger Haptic Display}, journal = {Haptic Interfaces for Virtual Environment and Teleoperator Systems, 2005. WHC 2005.}, pages = {606-608}, year = {2005}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep208.pdf}, abstract = {The Fingertip Haptic Display (FHD) is a five bar mechanism developed at the University of Washington for haptic interaction with the fingertip of the operator. The twodegree- of-freedom mechanism was computer optimized to accommodate the workspace of the human finger in flexion/ extension with a high degree of kinematic isotropy. Direct drive with frictionless flat-coil actuators ensure low torque ripple, inertia, and static friction in the actuation system for high fidelity haptic rendering. This paper describes a redesign of the position sensing arrangement, I/O hardware and software as well as thermal modelling to improve performance and stack four devices for use with index, middle, ring and little finger in a multifinger haptic display. Promising applications are expected to include palpation training for medical personnel, museum displays enabling the visitor to “touch” art, as well as psychophysics research: exploring the limits of human touch perception.}, contents = {208} } @article{BRL206, author = {M.H. Lum and D.C.W. Friedman and H.H. King and T. Broderick and M.N. Sinanan and J. Rosen and B. Hannaford}, title = {Field Operation of a Surgical Robot via Airborne Wireless Radio Link}, journal = {IEEE Int. Conf. on Field and Service Robotics}, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep206.pdf}, abstract = {Robotic assisted surgery generates the possibility of remote operation between surgeon and patient. We need better understanding of the engineering issues involved in operating a surgical robot in remote locations and through novel communication links between surgeon and surgery site. This paper describes two recent experiments in which we tested a new prototype surgical robot manipulation system in field and laboratory conditions. In the first experiment, we set up the robot in a remote pasture land and ran it on generator power. Telecommunication with the surgical control station was provided by a novel airborne radio link supported by an unmanned arial vehicle. In the second experiment, we teleoperated the robot over an Internet link between Imperial College London and our laboratory in Seattle. Data are reported on surgeon completion times for basic tasks and on network latency experience. The results are a small step towards teleoperated surgical robots which can be rapidly deployed in emergency situations in the field.}, contents = {206} } @inproceedings{BRL205, author = {R. Donlin and R. Leuschke and B. Hannaford}, title = {Experimental Evaluation of Attachment Methods for a Multifinger Haptic Device}, booktitle = {Proceedings of World Haptics 2007}, address = {Japan}, month = {March 22}, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep205.pdf}, abstract = {Due to the nature of touch sensation, the interface between a user and a haptic device must be carefully designed and selected such that the user feels they are directly manipulating a virtual object. This is particularly critical for attachment of fingertips to a multi fingered device. We experimentally tested eight methods of attachment for a Multifinger Haptic Device (MFHD) previously developed in our lab. From the test we gathered objective and subjective data on force and user preference. Based on this data we were able to evaluate the quality of the attachment methods.}, contents = {205} } @inproceedings{BRL204, author = {B. Hannaford and R. Leuschke}, title = {Fast Rendering for a Multifinger Haptic Display}, booktitle = {Proceedings of World Haptics 2007}, address = {Japan}, month = {March 22}, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep204.pdf}, abstract = {An algorithm is described for fast rendering of surfaces for haptic interaction with multiple fingers. The algorithm uses a human-defined geometrical map to quickly cache surface triangles for constant time solution of the collision detection problem. The map is a 1, 2, or 3 dimensional manifold onto which it is easy to project the haptic interaction point. Dividing it's surface into quantized bins allows easy reference to a small set of triangles which can be checked for collision. Although the algorithm relies on some one-time manual input (i.e. defining the contact map), it represents a significant increase in speed without a substantial memory penalty.}, contents = {204} } @inproceedings{BRL202, author = {D.W. Friedman and J. Dosher and T. Kowalewski and J. Rosen and B. Hannaford}, title = {Automated Tool Handling for the Traumapod Surgical Robot}, booktitle = {Proceedings of IEEE Int. Conf. on Robotics and Automation, ICRA2007, Rome Italy}, month = may, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep202.pdf}, abstract = {In order to enable robotic surgery without human assistance, a means must be developed to change tools. As part of the larger Traumapod Project, we developed the Tool Rack Subsystem --- an automated tool rack capable of holding, accepting, and dispensing up to 14 tools for the DaVinci(TM) surgical robot. Borrowing some techniques from industrial automation, we developed a robust system capable of presenting any stored tool in 700 ms or less. Tools were positively retained in a sterilizable carosel in a compliant manner designed to accomodate misalignment during tool exchange. RFID equipment was integrated into the system and the tools so that tools could be inventoried and presented by function or serial number instead of rack position. The resulting device has completed testing and integration into the Traumapod system and met all its design requirements.}, contents = {202} } @inproceedings{BRL201, author = {S. De and A. Dagan and P. Roan and J. Rosen and M. Sinanan and M. Gupta and B. Hannaford}, title = {CIELab and sRGB color values of in vivo normal and grasped porcine liver}, booktitle = {Proceedings MMVR 2007}, address = {Long Beach, CA}, month = {Feb 6-9}, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep201.pdf}, abstract = {Surgical simulators are excellent training tools for minimally invasive procedures but are currently lacking in realistic tissue rendering and tissue responses to manipulation. Accurate color representation of tissues may add realism to simulators and provide medically relevant information. The goal of this study was to determine feasible methods for measuring color of in vivo tissue, specifically liver, in a standardized color space. Several compressions were applied to in vivo porcine liver. Three methods were then used to determine the CIELab and/or sRGB colors of normal and damaged liver. Results suggest that there are significant differences between normal and damaged liver color.}, contents = {201} } @inproceedings{BRL200, author = {R. Leuschke and A. Bhandari and B. Sires and B. Hannaford}, title = {Low Cost Eye Surgery Simulator with Skill Assessment Component}, booktitle = {Proceedings MMVR 2007}, address = {Long Beach, CA}, month = {Feb 6-9}, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep200.pdf}, abstract = {Ophthalmic surgeons require years of training and continuous practice to successfully manipulate the delicate tissues of the human eye. Development of the fine motor skills is a crucial component of this training. Virtual eye surgery simulators have come on the market in recent years leveraging the advantages of virtual procedures. However adoption is limited by the high initial investment and availability of models. Our approach consists of a low cost hybrid approach that employs a standard porcine model for cataract training and a platform that is instrumented to record interaction forces and video. In a preliminary study we have recorded procedure data for a small number of experts which shows good signal-to-noise ratio suitable for development of objective skill assessment models.}, contents = {200} } @inproceedings{BRL198, author = {J. Lester and T. Choudhury and N. Kern and G. Borriello and B. Hannaford}, title = {A Hybrid Discriminative/Generative Approach for Modeling Human Activities}, booktitle = {Proceedings of the Nineteenth International Joint Conference on Artificial Intelligence}, pages = {766 - 722}, address = {Edinburgh, Scotland}, year = {2005}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep198.pdf}, abstract = {Accurate recognition and tracking of human activities is an important goal of ubiquitous computing. Recent advances in the development of multi-modal wearable sensors enable us to gather rich datasets of human activities. However, the problem of automatically identifying the most useful features for modeling such activities remains largely unsolved. In this paper we present a hybrid approach to recognizing activities, which combines boosting to discriminatively select useful features and learn an ensemble of static classifiers to recognize different activities, with hidden Markov models (HMMs) to capture the temporal regularities and smoothness of activities. We tested the activity recognition system using over 12 hours of wearable-sensor data collected by volunteers in natural unconstrained environments. The models succeeded in identifying a small set of maximally informative features, and were able identify ten different human activities with an accuracy of 95\%.}, contents = {198} } @inproceedings{BRL197, author = {J. Lester and B. Hannaford and G. Borriello}, title = {'Are You with Me?' - Using Accelerometers to Determine If Two Devices Are Carried by the Same Person}, booktitle = {Proceedings of the Second International Conference on Pervasive Computing}, pages = {33-50}, address = {Vienna, Austria}, year = {2004}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep197.pdf}, abstract = {As the proliferation of pervasive and ubiquitous computing devices continues, users will carry more devices. Without the ability for these devices to unobtrusively interact with one another, the user’s attention will be spent on coordinating, rather than using, these devices. We present a method based on a coherence function, a measure of linear correlation in the frequency domain, to reliably analyze walking data recorded by low-cost MEMS accelerometers to determine if two devices are carried by the same person. We use inexpensive accelerometers and show that these sensors perform similarly to more expensive accelerometers for the frequency range of human motion, 0 to 10Hz. We also present results from a large test group illustrating the algorithm’s robustness and its ability to withstand real world time delays, crucial for wireless technologies like Bluetooth and 802.11. We present results that show that our technique is 100\% accurate using a sliding window of 8 seconds of data and the devices are carried in the same location on the body (we also present results for when devices are carried on different parts of the body), is tolerant to inter-device communication latencies, and requires little communication bandwidth.}, contents = {197} } @inproceedings{BRL196, author = {G. Sankaranarayanan and B. Hannaford}, title = {Virtual Coupling Schemes for Causality Control in Networked Haptic Environments}, booktitle = {Proceedings of the 2006 BioRob Conference}, address = {Pisa, Italy}, month = feb, year = {2006}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep196.pdf}, abstract = {In networked haptic environments, multiple users remotely collaborate sharing the same virtual space; such environments are used in surgical simulation training, maintenance, and task-training, among other applications. It is vital to maintain causality of events in them, and thus achieve consistency in collaboration. This is especially true in the presence of time delays between the users. Usually, client-server architecture is widely used to control this problem in networked haptic environments. This method introduces a round-trip delay for each user and relies on the ability of the client to maintain communication with the server. In contrast, peer-to-peer architecture allows time delay to be reduced to half compared to client-server based methods by multicasting the information from each user to all the others. It presents, however, the greatest difficulties to control causality between the users. This paper presents two virtual coupling schemes to control causality in a peer-to-peer architecture. The performance of the schemes for constant time delays were compared to server based method. The experimental results obtained demonstrate that one of the virtual coupling schemes has a comparable performance to server-based method. Therefore, this scheme allows multiple users to collaborate without relying on a sever and, at the same time, maintaining causality among them.}, contents = {196} } @inproceedings{BRL195, author = {S. De and P. Swanson and M.N. Sinanan and J. Rosen and A. Dagon and B. Hannaford}, title = {Tissue Damage due to Mechanical Stresses as applied during Minimally Invasive Surgery}, booktitle = {Proceedings of the 2006 BioRob Conference}, address = {Pisa, Italy}, month = feb, year = {2006}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep195.pdf}, abstract = {While there are many benefits to minimally invasive surgery, force feedback, or touch sensation, is lacking in the currently available MIS tools, including surgical robots, creating the potential for excessive force application during surgery. The goal of this work was to develop a methodology with which to identify stress magnitudes and durations that can be safely applied with a grasper to different tissues, helping to improve MIS device design and reduce potential for clinically relevant consequences. Using the porcine model, stresses typically applied in MIS were applied to liver, ureter, and small bowel using a motorized endoscopic grasper. Acute indicators of tissue damage including cellular death, activation of the coagulation cascade, and infiltration of inflammatory cells were measured using histological and image analysis techniques. ANOVA and post-hoc analyses were used to detect stress magnitudes and durations that caused significantly increased tissue damage with the goal to ultimately identify safe stress ‘thresholds’ during grasping of the studied tissues. Preliminary data suggests a graded non-linear response between applied stress magnitude and apoptosis in liver and small bowel as well as granulocyte infiltration in small bowel.}, contents = {195} } @inproceedings{BRL194, author = {J.C. Perry and J. Rosen}, title = {Design of a 7 Degree-of-Freedom Upper-Limb Powered Exoskeleton}, booktitle = {Proceedings of the 2006 BioRob Conference}, address = {Pisa, Italy}, month = feb, year = {2006}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep194.pdf}, abstract = {The exoskeleton is an external structural mechanism with joints and links corresponding to those of the human body. Worn by the human, the exoskeleton transmits torques from proximally located actuators through rigid exoskeletal links to the human joints. This paper presents the development of an anthropometric seven degree-of-freedom powered exoskeleton for the upper limb. The design was based on a database defining the kinematics and the dynamics of the upper limb during daily living activities, as well as workspace analyses, joint ranges of motion, and joint physiological and upper limb anatomical considerations. Proximal placement of motors and distal placement of pulley reductions were incorporated into the design of a cable-driven wearable robotic arm. This design led to low inertias, high-stiffness links, and back-drivable transmissions with zero backlash. Potential applications of the exoskeleton as a wearable robot include use as: (1) a therapeutic and diagnostics device for physiotherapy, (2) an assistive (orthotic) device for human power amplifications, (3) a haptic device in virtual reality simulation, and (4) a master device for teleoperation.}, contents = {194} } @inproceedings{BRL193, author = {M.J.H. Lum and D. Trimble and J. Rosen and H. King and G. Sankarayanaranan and J. Dosher and R. Leuschke and B Martin-Anderson and M.N. Sinanan and B. Hannaford}, title = {Multidisciplinary approach for developing a  new minimally invasive surgical robot system}, booktitle = {Proceedings of the 2006 BioRob Conference}, address = {Pisa, Italy}, month = feb, year = {2006}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep193.pdf}, abstract = {The medical profession is constantly evolving and improving in order to provide physicians with better tools and techniques for delivering patients with more effective health care solutions. Minimally invasive surgery (MIS) revolutionized the way in which a number of surgical procedures are performed resulting in quicker postoperative recovery times. Surgical robotics provides a new paradigm to further improve MIS interventions. For more than a decade, the close collaboration between the BioRobotics Lab and the Center for Video Endscopic Surgery has taken an engineering approach to solving clinically relevant questions. A large set of force/torque and displacement data was collected using a device called the Blue Dragon. This data served as a design specification for a kinematic optimisation of a spherical mechanism for a new surgical robot manipulator. Once the mechanism was optimised a 6-DOF cable actuated surgical manipulator was designed and developed providing all the degrees of freedom of manual MIS plus the addition of a wrist at the surgical end-effector. Supporting electronics and controls software has been developed and integrated into the system so that the surgical manipulator can be teleoperated across a single bi-direction UDP socket via a remote master device. We present the design approach as well as the current state of our system. Future development will include bilateral teleoperation and clinical trials on porcine models.}, contents = {193} } @inproceedings{BRL192, author = {T. Mackel and J. Rosen and C. Pugh}, title = {Data Mining of the {E}-pelvis Simulator Database {A} Quest for a Generalized Algorithm for Objectively Assessing Medical Skill}, booktitle = {Proceedings of Medicine Meets Virtual Reality}, pages = {355-360}, address = {Long Beach, CA}, month = jan, year = {2006}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep192.pdf}, abstract = {Inherent difficulties in evaluating clinical competence of physicians has lead to the widespread use of subjective skill assessment techniques.  Inspired by an analogy between medical procedure and spoken language, proven modeling methods in the field of speech recognition were adapted for use as objective skill assessment techniques. A generalized methodology using Markov Models (MM) was developed. The database under study was collected with the E-Pelvis physical simulator. The simulator incorporates an array of five contact force sensors located in key anatomical landmarks. Two 32-state fully connected MMs are used, one for each skill level. Each state in the model corresponds to one of the possible combinations of the 5 active contact force sensors distributed in the simulator. Statistical distances measured between models representing subjects with different skill levels are sensitive enough to provide an objective measure of medical skill level. The method was tested with 41 expert subjects and 41 novice subjects in addition to the 30 subjects used for training the MM. Of the 82 subjects, 76 were classified correctly (92\%). Moreover, unique state transitions as well as force magnitudes for corresponding states (expert/novice) were found to be skill dependent. Given the white box nature of the model, analyzing the MMs provides insight into the examination process performed. This methodology is independent of the modality under study. It was previously used to assess surgical skill in a minimally invasive surgical setup using the Blue DRAGON, and it is currently applied to data collected using the E-Pelvis.}, contents = {192} } @inproceedings{BRL191, author = {K. Fodero and H. King and M. J.H. Lum and C. Bland and J. Rosen and M.N. Sinanan and B. Hannaford}, title = {Control System Architecture for a Minimally Invasive Surgical Robot}, booktitle = {Proceedings of Medicine Meets Virtual Reality}, pages = {156-158}, address = {Long Beach, CA}, month = jan, year = {2006}, contents = {191} } @inproceedings{BRL190, author = {M.J.H. Lum and D. Warden and J. Rosen and M.N. Sinanan and B. Hannaford}, title = {Hybrid analysis of a spherical mechanism for a minimally invasive surgical ({MIS}) robot - design concepts for multiple optimizations}, booktitle = {Proceedings of Medicine Meets Virtual Reality}, pages = {349-354}, address = {Long Beach, CA}, month = jan, year = {2006}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep190.pdf}, abstract = {Several criteria exist for determining the optimal design for a surgical robot. This paper considers kinematic performance metrics, which reward good kinematic performance, and dynamic performance metrics, which penalize poor dynamic performance. Kinematic and dynamic metrics are considered independently, and then combined to produce hybrid metrics. For each metric, the optimal design is the one that maximizes the performance metric over a specific design space. In the case of a 2-DOF spherical mechanism for a surgical robot, the optimal design determined by kinematic metrics is a robot arm with link angles ( alpha\_12 = 90deg, alpha\_23 = 90deg). The large link angles are the most dextrous, but have the greatest risk of robot-robot or robot-patient collisions and require the largest actuators. The link lengths determined by the dynamic metrics are much shorter, which reduces the risk of collisions, but tend to place the robot in singularities much more frequently. When the hybrid metrics are used, and a restriction that the arm must be able to reach a human’s entire abdomen, the optimal design is around ( alpha\_12 = 51deg, alpha\_23 = 54deg). The hybrid design provides a compromise between dexterity and compactness.}, contents = {190} } @article{BRL188, author = {J. Rosen and M. Lum and D. Trimble and B. Hannaford and M. Sinanan}, title = {Spherical Mechanism Analysis of a Surgical Robot for Minimally Invasive Surgery - Analytical and Experimental Approaches}, journal = {Studies in Health Technology and Informatics - Medicine Meets Virtual Reality, (MMVR05)}, volume = {111}, pages = {422-428}, publisher = {IOS Press}, month = jan, year = {2005}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep188.pdf}, abstract = {Recent advances in technology have led to the fusion of MIS techniques and robot devices. However, current systems are large and cumbersome. Optimizing the surgical robot mechanism will eventually lead to its integration into the operating room (OR) of the future becoming the extended presence of the surgeon and nurses in a room occupied by the patient alone. By optimizing a spherical mechanism using data collected in-vivo during MIS procedures, this study is focused on a bottom-up approach to developing a new class of surgical robotic arms while maximizing their performance and minimizing their size. The spherical mechanism is a rotational manipulator with all axes intersecting at the center of the sphere. Locating the rotation center of the mechanism at the MIS port makes this class of mechanism a suitable candidate for the first two links of a surgical robot for MIS. The required dexterous workspace (DWS) is defined as the region in which 95\% of the tool motions are contained based on in-vivo measurements. The extended dexterous workspace (EDWS) is defined as the entire abdominal cavity reachable by a MIS instruments. The DWS is defined by a right circular cone with a vertex angle of 60 deg and the EDWS is defined by a cone with an elliptical cross section created by two orthogonal vertex angles of 60 deg. and 90 deg. A compound function based on the mechanism's isotropy and the mechanism stiffness was considered as the performance metric cost function. Optimization across both the DWS and the EDWS lead to a serial mechanism configuration with link length angles of 74 deg and 60 deg for a serial configuration This mechanism configuration maximized the kinematic performance in the DWS while keeping the EDWS as its reachable workspace. Surgeons, using a mockup of two mechanisms in a MIS setup, validated these results experimentally.  From these experiments the serial configuration was deemed most applicable for MIS robotic applications compared to a parallel mechanism configuration. The mechanical design of a cable actuated surgical robot was based on optimized link length angles. The system is currently being integrated into a fully operated two-arm system.  Small form-factor surgical robotic arms with optimized dexterous workspaces will facilitate the integration of multiple arms while avoiding self-collision in the OR of the future.}, contents = {188} } @inproceedings{BRL183, author = {J.H. Ryu and B. Hannaford and C. Preusche and G. Hirzinger}, title = {Time Domain Passivity Control with Reference Energy Behavior}, booktitle = {Proc. IEEE/RSJ International Conference on Intelligent Robots and Systems}, pages = {2932-2937}, address = {Las Vegas}, year = {2003}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep183.pdf}, abstract = {A recently proposed method for stabilizing haptic interfaces and teleoperation systems was tested with a "PHANToM" commercial haptic device. The "Passivity Observer" (PO) and "Passivity Controller" (PC) stabilization method was formed to stabilize the system but also excite high frequency mode in the device. To solve this problem, we propose a method to use a time-varying desired energy threshold instead of fixed zero energy threshold for the PO, and make the actual energy input follow the time-varying energy threshold. With the time-varying energy threshold, we make the PC control action smooth without sudden impulsive behavior by distributing the dissipation. The proposed new PO/PC approach is applied to PHANToM with high stiffness (K = 500N/m), and stable and smooth contact is guarantee. Resetting and active environment display problems also can be solved with the reference energy following idea.}, contents = {183} } @article{BRL177, author = {J.D. Brown and J. Rosen and L. Chang and M. Sinanan and B. Hannaford}, editor = {J.D. Westwood}, title = {Quantifying Surgeon Grasping Mechanics in Laparoscopy Using the Blue {DRAGON} System}, journal = {Studies in Health Technology and Informatics - Medicine Meets Virtual Reality 13}, pages = {34-36}, publisher = {IOS Press}, year = {2004}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep177.pdf http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep177.pdf}, abstract = {Mechanical testing of abdominal organs has a profound impact on surgical simulation and surgical robotics development. Due to the nonlinear and viscoelastic nature of soft tissue it is crucial to test them in surgically relevant ranges of applied force, deformation, and duration for incorporating haptic realism into surgical simulators and for safe operation of surgical robots. In order to determine these ranges, a system known as the Blue DRAGON was used to track the motions and the forces applied to surgical tools during live procedures for quantifying how surgeons typically perform a minimally invasive surgical procedure. Thirty-one surgeons of varying skill were recorded performing three different surgical tasks. Grasping force (as applied to the tool handles) and handle angle for each tool were the signals of interest among 26 channels total acquired by the system in real time. These data were analyzed for their magnitudes and frequency content. Using the tool contact state, an algorithm selected tissue grasps to analyze measures during grasps only, as well as obtain grasp durations. The mean force applied to the tool handles during tissue grasps was 8.52 N ± 2.77 N; maximum force was 68.17 N. Ninety-five percent of the handle angle frequency content was below 1.98 Hz ± 0.98 Hz. Average grasp time was 2.29 s ± 1.65 s, and 95\% of all grasps were held for 8.86 s ± 7.06 s or less. The average maximum grasp time during these tasks was 13.37 s ± 11.42 s. These results form the basis for determining how abdominal tissues are to be mechanically tested in ranges and durations of force and deformation that are surgically realistic. Additionally, this information may serve as design specifications for new surgical robots or haptic simulators.}, contents = {177} } @article{BRL176, author = {Brown and J. Rosen and M. N. Sinanan and B. Hannaford}, title = {In-Vivo and Postmortem Compressive Properties of Porcine Abdominal Organs}, journal = {Lecture Notes in Computer Science, Medical Image Computing and Computer-Assisted Intervention - MICCAI 2003}, volume = {2878}, pages = {238 -245}, address = {Toronto, Canada.}, year = {2003}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep176.pdf}, abstract = {In order to provide realistic haptic feedback, simulators must incorporate accurate computational models of the in-vivo mechanical behavior of soft tissues. Surgical simulation technology has progressed rapidly but lacks a comprehensive database of soft tissue mechanical properties with which to incorporate. Simulators are often designed purely based on what "feels about right;" quantitative empirical data are lacking. It is important to test tissues in-vivo and apply surgically relevant ranges of force, deformation, and duration. A motorized endoscopic grasper was used to test seven porcine abdominal organs invivo, in-situ, and ex-corpus with cyclic and static compressive loadings. Elastic and stress relaxation characteristics were examined. Results from liver are presented here. Notable differences were found between successive squeezes and between conditions for elastic and relaxation behaviors.}, contents = {176} } @inproceedings{BRL175, author = {M.J.H. Lum and J. Rosen and M. Sinanan and B. Hannaford}, title = {Kinematic optimization of a spherical mechanism for a minimally invasive surgical robot.}, booktitle = {Proc. IEEE International Conference on Robotics and Automation}, address = {New Orleans, La}, month = may, year = {2004}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep175.pdf}, abstract = {Advances in surgical technology allow physicians to more effectively provide care to their patients.  Minimally invasive surgery (MIS) has revolutionized the way a significant number of procedures are performed.  Recent advances in technology have led to the fusion of MIS techniques and robot devices.  Current systems are large and cumbersome.  By optimizing a spherical mechanism using in-vivo data collected during MIS procedures, this paper is focused on a bottom-up approach in developing a new class of surgical robot arms. The spherical mechanism is a rotational manipulator with all axes intersecting at the center of the sphere. Locating the rotation center of the mechanism at the MIS port makes this class of mechanism a suitable candidate for the first two links of a surgical robot for MIS. The required dexterous workspace (DWS) is defined as a high dexterity region defined by a right circular cone with a vertex angel of 60 deg in which 95\% of the tool motions are contained based on in-vivo measurements. The extended dexterous workspace (EDWS) is defined as the workspace required to reach the entire abdominal cavity with MIS instruments and defined by a cone with an elliptical cross section created by two orthogonal vertex angels of 60 deg and 90 deg . For optimizing the mechanism structure, the forward and inverse kinematics as well as the Jacobian matrix were derived. Using the Jacobian, mechanism isotropy was considered as the performance metric. Optimization across both the DWS and a superset of the EDWS lead to a mechanism configuration with link length angles of 52 deg and 40 deg that maximizes kinematic performance and compactness. The workspace of this design covers the entire EDWS. By directly applying in-vivo experimental data from MIS in order to optimize the spherical manipulator, a design that maximizes performance and minimizes size has been developed.  A pair of prototype manipulators will be developed based on these results.}, contents = {175} } @inproceedings{BRL174, author = {T.M. Kowalewski and J. Rosen and L. Chang and M. Sinanan and B. Hannaford}, title = {Optimization of a vector quantization codebook for objective evaluation of surgical skill.}, booktitle = {Proc. Medicine Meets Virtual Reality 12}, pages = {174-179}, month = jan, year = {2004}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep174.pdf}, abstract = {Surgical robotic systems and virtual reality simulators have introduced an unprecedented precision of measurement for both tool-tissue and tool-surgeon interaction; thus holding promise for more objective analyses of surgical skill.  Integrative or averaged metrics such as path length, time-to-task, success/failure percentages, etc., have often been employed towards this end but these fail to address the processes associated with a surgical task as a dynamic phenomena.  Stochastic tools such as Markov modeling using a 'white-box' approach have proven amenable to this type of analysis. While such an approach reveals the internal structure of the of the surgical task as a process, it requires a task decomposition based on expert knowledge, which may result in a relatively large/complex model. In this work, a 'black box' approach is developed with generalized cross-procedural applications., the model is characterized by a compact topology, abstract state definitions, and optimized codebook size. Data sets of isolated tasks were extracted from the Blue DRAGON database consisting of 30 surgical subjects stratified into six training levels.  Vector quantization (VQ) was  employed on the entire database, thus synthesizing a lexicon of discrete, task-independent surgical tool/tissue interactions. VQ has successfully established a dictionary of 63 surgical code words and displayed non-temporal skill discrimination.  VQ allows for a more  cross-procedural analysis without relying on a thorough study of the procedure, links the results of the black-box approach to observable phenomena, and reduces the computational cost of the analysis by discretizing a complex, continuous data space.}, contents = {174} } @inproceedings{BRL171, author = {G. Lee and B. Hannaford}, title = {Anisotropies of Touch in Haptic Icon Exploration}, booktitle = {IEEE/RSJ International Conference on Intelligent Robots and Systems}, address = {Las Vegas}, month = oct, year = {2003}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep171.pdf}, abstract = {Handheld devices are enhancing many aspects of our lives. As increasingly complex devices appear with decreasing form factors, haptics may become an essential tool for interacting with them. In this regime of operation, issues of power, weight and volume are of significant importance. The haptic thresholds of the index finger for active exploration of a two dimensional virtual environment for two icon alignments and two finger motions were measured. Using all possible combinations of two finger motions, flexion/extension and finger abduction/adduction, and two icon alignments, vertical and horizontal, were measured separately. Haptic thresholds ranged from 15 to 24 milliNewtons. Thresholds were affected by finger motion, but not by icon alignment.}, contents = {171} } @inproceedings{BRL170, author = {C. Preusche and G. Hirzinger and J.H. Ryu and B. Hannaford}, title = {Time Domain Passivity Control for 6 Degrees of Freedom Haptic Displays}, booktitle = {IEEE/RSJ International Conference on Intelligent Robots and Systems}, pages = {2944-9249}, address = {Las Vegas}, month = oct, year = {2003}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep170.pdf}, abstract = {In this paper a modification of the time domain passivity controller is presented to improve its performance and transparency in case of multi degrees of freedom (dof) haptic interaction. In multi-dof application the concept needs to be extended by additional conditions to distribute the adaptive damping appropriately among the degrees of free-dom. This can be solved by using the geometrical information coded in the output signals of the system. Experiments show the validity of this concept.}, contents = {170} } @inproceedings{BRL169, author = {Lee G.S. and Hannaford B}, title = {Preliminary two dimensional haptic thresholds and task performance enhancements}, booktitle = {Proceedings, 2003 Haptics Symposium}, pages = {85-90}, publisher = {IEEE Computer Society Press}, address = {Los Angeles, CA}, month = mar, year = {2003}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep169.pdf}, abstract = {Many tasks may be performed with greater efficiency and speed with hapticas sistance. Using the Penbased Haptic Display, a low-power, low-friction, and high-precision device, we performed two separate experiments to measure two properties of human/haptic interactions. In the first ex-periment, we measured the level of force at which a subject may detect the presence of haptic feedback at a 71\% accuracy level using a converging adaptive threshold algorithm. The average haptic threshold of eleven subjects was 20.8 milliNewtons. The second experiment quantifies changes in task performance using Fitts Law. We measured improve-ments at three force levels compared to no force.}, contents = {169} } @inproceedings{BRL168, author = {G.K. Klute and Czerniecki, J., and B. Hannaford}, title = {Muscle-Like Pneumatic Actuators for Below-Knee Prostheses,}, booktitle = {Proceedings, Actuator 2000: 7th International Conference on New Actuators}, pages = {289-292}, address = {Bremen, Germany}, month = {June 19-21}, year = {2000}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep168.pdf}, abstract = {This paper reports on the design of a biorobotic actuator intended for use in a powered, below-knee prosthesis. Design requirements for the artificial muscle and tendon are based on the properties of the natural limb. As biological properties often exhibit significant variability, data from a variety of vertebrate species are extracted from published reports in the biological literature and used to specify model parameters of both muscle and tendon. To achieve the required relationships between force, length, velocity, and activation, an artificial myo-tendinous actuator is proposed whose components include a flexible, pneumatic actuator, a hydraulic damper, and die compression springs. To verify performance, a series of tests were conducted that enveloped the conditions expected from a muscle-tendon unit used as an actuator for a below-knee prosthesis. The experimental results show the force-length-velocity properties of the artificial myo-tendinous actuator to be similar to its biological counterpart.}, contents = {168} } @article{BRL167, author = {Jee-Hwan Ryu and Yoon Sang Kim and Blake Hannaford}, title = {Sampled and Continuous Time Passivity and Stability of Virtual Environments}, journal = {IEEE Int. Conf. on Robotics \& Automation 2003}, pages = {822-827}, address = {Taipei, Taiwan}, month = sep, year = {2003}, abstract = {We propose new time domain Passivity Observer (PO) and Passivity Controller(PC) with removing the constant velocity assumption during one sample time,which was used in our previous PO/PC approach to estimate one step ahead future energy output. Due to this assumption, in certain cases, the previous PO can not observe the active energy output from the virtual environment. In this paper, we analyze the energy output from the virtual environment in continuous time domain, and introduce the sampled time definition of passivity. This new definition iscompared with the previous sampled time definition of passivity. Through this comparison, we propose themore accurate PO/PC approach. To satisfy the stability for all continuous and sampled time domain, we analyze the energy behavior in-between sample with considering the velocitychange within one sample time. The proposed new PO/PC approach is applied to "Excalibur" haptic interfacesystem with very high stiffness \$(K = 120KN/m)\$, and we can guarantee stable contact.}, contents = {167} } @article{BRL166, author = {J. Rosen and L. Chang and J. D. Brown and B. Hannaford and M. Sinanan and R. Satava}, title = {Minimally Invasive Surgery Task Decomposition - Etymology of EndoscopicSuturing}, journal = {Studies in Health Technology and Informatics - Medicine Meets Virtual Reality}, volume = {94}, pages = {295-301}, publisher = {IOS Press}, address = {Newport Beach, CA}, month = jan, year = {2003}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep166.pdf}, abstract = {The analogy between Minimally Invasive Surgery (MIS) and the human language inspires the decomposition of a surgical task into its primary elements. The frequency of different elements or "words" and their sequential associations or "grammar" both hold critical information about the process and outcome of the procedure. Modeling these sequential element expressions using a multi finite states model (Markov model) reveals the grammatical structure of the surgical task and is utilized as one of the key steps in objectively assessing surgical performance. The experimental protocol included 30 surgeons at different levels of training (5xR1,R2,R3,R4,R5, and experts) performing Laparoscopic suturing on an animal model (pig). The kinematics and dynamics of left and right endoscopic tools along with the visual view of the surgical scene were acquired by the Blue DRAGON system. The methodology of decomposing the surgical task is based on a fully connected,finite-states (30 states) Markov model (MM) where the left and right hands arerepresented by 15 states each. In addition to the MM objective analysis, a scoring protocol was used by an expert surgeon to subjectively assess the subjects' technical performance. An objective learning curve was defined based on measuring quantitative statistical distance (similarity) between MM of experts and MM of residents at different levels of training. The objective learning curve (e.g.statistical distance between MM) was similar to that of the subjective performance analysis. The MM proved to be a powerful and compact mathematical model for decomposing a complex task such as laparoscopic suturing. Systems like surgical robots or virtual reality simulators that inherently measure the kinematics and dynamics of the surgical tool may benefit from inclusion of the proposed methodology for analysis of efficacy and objective evaluation of surgical skills during training.}, contents = {166} } @article{BRL165, author = {J. D. Brown and J. Rosen and Y. S. Kim and L. Chang and M. Sinanan and B. Hannaford}, title = {In-Vivo and In-Situ Compressive Properties of Porcine Abdominal Soft Tissues}, journal = {Studies in Health Technology and Informatics - Medicine Meets Virtual Reality}, volume = {94}, pages = {26-32}, publisher = {IOS Press}, address = {Newport Beach, CA.}, month = jan, year = {2003}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep165.pdf}, abstract = {Accurate biomechanical characteristics of tissues are essential for developing realistic virtual reality surgical simulators utilizing haptic feedback. Surgical simulation technology has progressed rapidly but lacks a comprehensive database of soft tissue mechanical properties with which to incorporate. Simulators are often designed purely based on what "feels right; "quantitative empirical data are lacking. A motorized endoscopic grasper was used to test abdominal porcine tissues in-vivo and in-situ with cyclic and static compressive loadings. An exponential constitutive equation was fit to the resulting stress-strain curves, and the coefficients were compared for various conditions. Stress relaxation for liver and small bowel were also examined. Differences between successive squeezes and between in-vivo and in-situ conditions were found.}, contents = {165} } @inproceedings{BRL164, author = {Jee-Hwan Ryu and Dong-Soo Kwon and Blake Hannaford}, title = {Control of a Flexible Manipulator with Noncollocated Feedback: Time Domain Passivity Approach}, booktitle = {The 2nd Joint IEEE CSS/RAS International Workshop on Control Problems in Robotics and Automation}, pages = {89-101}, address = {Las Vegas}, month = {Dec 14}, year = {2002}, abstract = {A new method to control a flexible manipulator with noncollocated feedback is proposed. We introduce a method to implement the time domain passivity control approach to a flexible manipulator with noncollocated feedback, which could not betreated with the previous time domain passivity control framework due to a possibly active transfer function from the collocated output to the noncollocated output. The developed method is simulated with the model of a single link flexible manipulator and we obtained a good control performance.}, contents = {164} } @inproceedings{BRL163, author = {Jee-Hwan Ryu and Dong-Soo Kwon and Blake Hannaford}, title = {Stability Guaranteed Control: Time Domain Passivity Approach}, booktitle = {IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS2002)}, pages = {2115-2121}, address = {Laussane, Switzerland}, year = {2002}, abstract = {A new, energy-based method is proposed for guaranteeing the stability of large classes of control systems with minimum performance losses. Based on a network presentation, the large classes of control systems are analyzed in a unified framework. In this unified network model, the concept of passivity is used to study the stability of large classes of control systems. For guaranteeing the stability condition, the time-domain passivity controller is extended to a 2-port network to make the controller 2-port passive. The developed method istested with numerical simulation in the regulation of a single link flexible manipulator. Totally stable control is achieved under wide variety of operating condition and uncertainties without any model information.}, contents = {163} } @inproceedings{BRL159, author = {B. Hannaford and J.H. Ryu and D.S. Kwon and Y.S. Kim and J.B. Song}, editor = {B. Siciliano and P. Dario}, title = {Testing Time Domain Passivity Control of Haptic Enabled Systems}, booktitle = {Experimental Robotics 2002: Proceedings of the International Symposium on Experimental Robotics 2002 (ISER-02)}, publisher = {Springer Verlag}, month = {July 9-12}, year = {2002}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep159.pdf}, abstract = {Much recent work has studied the means of achieving stable yet high performance control of haptic interfaces. Such interfaces provide compelling force feedback in virtual reality simulations for medical training, advanced computer aided design (CAD), entertainment, and other applications. This paper reports experimental testing of a new method of stable haptic interface control, the Passivity Observer (PO) and Passivity Controller (PC). Experimental results from three different laboratories confirm basic operation of the PO/PC. The PO/PC method is applied to high stiffness haptic interaction, to a 2-degree-of-freedom (DOF) system with coupled kinematics and dynamics, and to a bi-lateral telemanipulation system controlling metal-to-metal contact.}, contents = {159} } @inproceedings{BRL157, author = {J. Rosen and J.D. Brown and L. Chang and M. Barreca and M. Sinanan and B. Hannaford}, title = {The BlueDRAGON - {A} System for Measuring the Kinematics and the Dynamics of Minimally Invasive Surgical Tools In Vivo}, booktitle = {Proc. IEEE Intl. Conf. on Robotics and Automation ICRA-2002}, pages = {1876-1881}, address = {Arlington VA}, month = may, year = {2002}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep157.pdf}, abstract = {Minimally invasive surgery (MIS) involves a multi-dimensional series of tasks requiring a synthesis between visual information and the kinematics and dynamics of the surgical tools. Analysis of these sources of information is a key step in mastering MIS but may also be used to define objective criteria for characterizing surgical performance. The BlueDRAGON is a new system for acquiring the kinematics and the dynamics of two endoscopic tools along synchronized with the visual view of the surgical scene. It includes two four-bar passive mechanisms equipped with position and force torque sensors for measuring the positions and the orientations (P/O) of two endoscopic tools along with the forces and torques (F/T) applied by the surgeon's hands. The methodology of decomposing the surgical task is based on a fully connected, 28 finite-states Markov model where each states corresponded to a fundamental tool/tissue interaction based on the tool kinematics and associated with unique F/T signatures. The experimental protocol included seven MIS tasks performed on an animal model (pig) by 30 surgeons at different levels of their residency training including expert surgeons. Preliminary analysis of these data showed that major differences between residents at different skill levels were: (i) the types of tool/tissue interactions being used, (ii) the transitions between tool/tissue interactions being applied by each hand, (iii) time spent while performing each tool/tissue interaction, (iv) the overall completion time, and (v) the variable F/T magnitudes being applied by the subjects through the endoscopic tools. Systems like surgical robots or virtual reality simulators that inherently measure the kinematics and the dynamics of the surgical tool may benefit from inclusion of the proposed methodology for analysis of efficacy and objective evaluation of surgical skills during training.}, contents = {157} } @article{BRL156, author = {J.D. Brown and J. Rosen and M. Moreyra and M. Sinanan and B. Hannaford}, title = {Computer-Controlled Motorized Endoscopic Grasper for In Vivo Measurements of Soft Tissue Biomechanical Characteristics}, journal = {Studies in Health Technology and Informatics - Medicine Meets Virtual Reality}, volume = {85}, pages = {71-73}, publisher = {IOS Press}, address = {Newport Beach, CA}, month = jan, year = {2002}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep156.pdf}, abstract = {Accurate biomechanical characteristics of tissues are essential for developing realistic virtual reality surgical simulators utilizing haptic devices. Surgical simulation technology has progressed rapidly but without a large database ofsoft tissue mechanical properties with which to incorporate. The device described here is a computer-controlled, motorized endoscopic grasper capable of applying surgically relevant levels of force to tissue in vivo and measuring the tissue's force-deformation properties.}, contents = {156} } @article{BRL155, author = {J. Rosen and J.D. Brown and M. Barreca and L. Chang and B. Hannaford and M. Sinanan}, title = {The Blue {DRAGON} - {A} system for Monitoring the Kinematics and Dynamics of Endoscopic Tools in Minimally Invasive Surgery for Objective Laparoscopic Skill Assessment}, journal = {Studies in Health Technology and Informatics - Medicine Meets VirtualReality}, volume = {85}, pages = {412-418}, publisher = {IOS Press}, address = {Newport Beach, CA}, month = jan, year = {2002}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep155.pdf}, abstract = {Minimally invasive surgery (MIS) involves a multi-dimensional series of tasks requiring a synthesis between visual information and the kinematics and dynamics of the surgical tools. Analysis of these sources of information is a key step in mastering MIS surgery but may also be used to define objective criteria for characterizing surgical performance. The BlueDRAGON is a new system for acquiring the kinematics and the dynamics of two endoscopic tools along with the visual view of the surgical scene. It includes two four-bar mechanisms equipped with position and force torque sensors for measuring the positions and the orientations (P/O) of two endoscopic tools along with the forces and torques applied by the surgeon's hands. The methodology of decomposing the surgical task is based on a fully connected, finite-states (28 states) Markov model where each states corresponded to a fundamental tool/tissue interaction based on the tool kinematics and associated with unique F/T signatures. The experimental protocol included seven MIS tasks performed on an animal model (pig) by 30 surgeons at different levels of their residency training. Preliminary analysis of these data showed that major differences between residents at different skill levels were: (i) the types of tool/tissue interactions being used, (ii) the transitions between tool/tissue interactions being applied by each hand, (iii) time spent while performing each tool/tissue interaction, (iv) the overall completion time, and (v) the variable F/T magnitudes being applied by the subjects through the endoscopic tools. Systems like surgical robots or virtual reality simulators that inherently measure the kinematics and the dynamics of the surgical tool may benefit from inclusion of the proposed methodology for analysis of efficacy and objective evaluation of surgical skills during training}, contents = {155} } @inproceedings{BRL154, author = {J.H. Ryu and D.S. Kwon and B. Hannaford}, title = {Stable Teleoperation with Time Domain Passivity Control}, booktitle = {IEEE Intl. Conference on Robotics and Automation, ICRA 2002}, pages = {3260-3265}, address = {Washington, DC}, month = may, year = {2002}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep154.pdf}, abstract = {A new bilateral control scheme is proposed to ensure stable teleoperation under a wide variety of operating conditions. To guarantee the stability of a teleoperation system, a previously proposed energy-based method is extended to a two-port network. The issues in implementing the Passivity Observer and Passivity Controller to teleoperation systems are studied. The method is tested with our two-DOF master/slave teleoperation system. Totally stable teleoperation is achieved under conditions such as hard wall contact (stiffness $>$ 150 kN/m) and hard surface following.}, contents = {154} } @inproceedings{BRL153, author = {J. Dosher and B. Hannaford}, title = {Detection Thresholds for Small Haptic Effects}, booktitle = {Proceedings, SPIE Teleoperator and Telemanipulator Workshop}, address = {Boston MA}, month = {October 29}, year = {2001}, abstract = {In prior research we reported on experiments to measure the smallest haptic effects the FHD can meaningfully communicate to an operator (Dosher and Hannaford, 2001). These experiments varied the force displayed to the subject, with all other factors held constant. In this paper we report on experiments studying the effects of varying the size, shape, and pulse-duration of a haptic feature. We again measure the smallest haptic effects that can be meaningfully communicated to an operator; however, using a variation of icon widths, icon waveforms, and static pulse-widths. In this paper we measure the smallest detectable haptics effects with active exploration of saw-tooth shaped icons sized 3, 4 and 5 mm, a sine-shaped icon 5 mm wide, and static pulses 50, 100, and 150 ms in width. Smooth shaped icons resulted in a detection threshold of approximately 65 mN, twice that of saw-tooth shaped icons. In the case of static icons, longer pulse-widths corresponded to slightly higher threshold values.}, contents = {153} } @inproceedings{BRL148, author = {Y.S. Kim and B. Hannaford}, title = {Some Practical Issues in Time Domain Passivity Control of Haptic Interfaces}, booktitle = {Proceedings IROS 2001}, address = {Maui, Hawaii}, month = oct, year = {2001}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep148.pdf}, abstract = {In this paper, two major practical issues are studied to improve the performance of a new energy based method of achieving stable, high performance haptic interface control. The first issue is related to resetting the amount of energy accumulated in thePassivity Observer for faster operation. A heuristic method is derived and experimentally tested for the resetting and it is shown to help the PC to operate sooner when the system gets active. The second one was noise in velocity measurements being magnified into audible force signals by the controller. This issue was addressed by theintroduction of a velocity threshold and it is verified that the velocity threshold makes the PC more free from the noise effect at low velocity. Experimental results are presented for the "Excalibur" haptic device.}, contents = {148} } @inproceedings{BRL147, author = {G. Klute and J. Czerniecki and B. Hannaford}, title = {Artificial tendons: biomechanical design properties for prosthetic lowerlimbs}, booktitle = {Proc. 22nd Annual Intl. Conf. IEEE Engineering in Medicine and Biology Society and World Congress on Medical Physics and Biomedical Engineering}, volume = {3}, pages = {1972-5}, publisher = {IEEE}, address = {Chicago}, month = {July 24-28}, year = {2000}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep147.pdf}, abstract = {This paper reports on the design of an artificial tendon intended for use ina powered, lower limb prosthesis. To specify performance requirements, theproperties of mammalian weight bearing tendons are drawn from the literatureand compared with a number of existing tendon models. Based on the data,a mathematical model of an energy storing tendon is proposed and used todesign an artificial tendon that mimics the performance of the human Achillestendon. The proposed tendon design is a tradeoff betweena weight penalty and desired performance. Experimental results of thispractical design demonstrate desired performance.}, contents = {147} } @article{BRL145, author = {J. Rosen and M. Solazzo and B. Hannaford and M. Sinanan}, title = {Objective Laparoscopic Skills Assessments of Surgical Residents Using HiddenMarkov Models Based on Haptic Information and Tool/Tissue Interactions}, journal = {Studies in Health Technology and Informatics - Medicine Meets Virtual Reality}, volume = {81}, pages = {417-423}, address = {Newport Beach, CA}, month = jan, year = {2001}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep145.pdf}, abstract = {Laparscopic surgical skills evaluation of surgery residents is usually asubjective process, carried out in the operating room by senior surgeons. By its nature,this process is performed using fuzzy criteria. The objective of the current studentwas to develop and assess an objective laparoscopic surgical skill scale using HiddenMarkov Models (HMM) based on haptic information, tool/tissue interactions and visualtask decomposition. Methods: Eight subjects (six surgical trainees: first yearsurgical residents 2xR1, third year surgical residents 2xR3, fifth year surgical residents 2xR5, and two expert laparoscopic surgeons 2xES)performed laparoscopic cholecystectomyfollowing a specific 7 steps protocol on a pig. An instrumented laparoscopic grasperequipped with a three-axis force/torque sensor located at the proximal end with an additional force sensor located on the handle, was used to measure the forces and torques. The hand/tool interface force/torque data was synchronized with a video of the tool operative maneuvers. A synthesis of frame-by-frame video analysis was used todefine 14 different tyupes of tool/tissue interactions, each one associated with uniqueforce/torque (F/T) signatures. HMMs were developed for each subjectrepresenting the surgical skills by defining the various tool/tissue interactions as states andthe associated F/T signatures as observations. The statistical distance between theHMMs representing residents at different levels of their training and the HMMs ofexpert surgeons were calculated in order to generate a learning curve of selected stepsduring laparoscopic cholecystectomy. Results: Comparison of HMMs betweengroups showed significant differences between all skill levels, supporting the objective definition of a learning curve. The major differences between skill levels were: (i) magnitudes of F/T applied, (ii) types of tool/tissue interactions used and the transition between them and (iii) time intervals spent in each tool/tissue interaction and the overall completion time. The objective HMM analysis showed that the greatest difference in performance was between R1 and R3 groups and then decreased as the level ofexpertise increased, suggesting that significant laparoscopic surgical capability develops between the first and the third years of their residency training. The power of themethodology using HMM for objective surgical skill assessment arises from the fact that it compiles enormous amount of data regarding different aspects of surgical skill into a very compact model that can be translated into a single number representing the distance from expert performance. Moreover, the methodology is not limited to in-vivo condition as demonstrated in the current study. It can be extended to other modalities such as measuringperformance in surgical simulators and robotic systems.}, contents = {145} } @article{BRL144, author = {J. Longnion and J. Rosen and M. Sinanan and B. Hannaford}, title = {Effects of Geared Motor Characteristics on Tactile Perception of TissueStiffness}, journal = {Studies in Health Technology and Informatics - Medicine Meets Virtual Reality}, volume = {81}, pages = {286-292}, address = {Newport Beach, CA}, month = jan, year = {2001}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep144.pdf}, abstract = {Endoscopic haptic surgical devices have shown promise in addressing the lossof tactile sensation associated with minimally invasive surgery. However, thesedevices must be capable of generating forces and torques similar to those applied on thetissue with a standard endoscopic tool. Geared motors are a possible solution foractuation; however, they possess mechanical characteristics that could potentially interfere with tactile perception of tissue qualities. The aim of the current research was todetermine how the characteristics of a geared motor suitable for a haptic surgical deviceaffect a user's perception of stiffness. The experiment involved six blindfoldedsubjects who were asked to discriminate the stiffness of six distinct silicone rubbersamples whose mechanical properties are similar to those of soft tissue. Using a noveltesting device whose dimensions approximated those of an endoscopic grasper, eachsubject palpated 30 permutations of sample pairs for each of three types of mechanicalloads; the motor (friction and inertia), a flywheel (with the same inertia as motor),and a control (no significant mechanical interference). One fator ANOVA of the errorscores and palpation time showed that no significant difference existed among errorscores, but mean palpation time for the control was significantly less than for the othertwo methods. These results indicated that the mechanical characteristics of a geared motorchosen for application in a haptic surgical device did not interfere with the subjects'perception of the silicone samples' stiffness, but these characteristics may signficantlyaffect the energy expenditure and time required for tissue palpation. Therefore, beforegeared motors can be considered for use in haptic surgical devices, considerationshould be given to factors such as palpation speed and fatigue.}, contents = {144} } @inproceedings{BRL141, author = {K.N. Jaax and P.H. Marbot and B. Hannaford}, title = {Development of a Biomimetic Position Sensor for Robotic Kinesthesia}, booktitle = {Proceedings, IROS 2000}, address = {Takamatsu, Japan}, month = nov, year = {2000}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep141.pdf}, abstract = {Drawing from the rich source of proven and often novel mechanisms in the biological realm, biomimetic sensors are being successfully developed for many different transduction tasks. This paper presents such a sensor for transducing displacements. Our sensor is a robotic analog of the biological muscle spindle, an actuated position sensor whichtransduces muscle displacement for kinesthetic awareness. The mechanical filter exhibits the desired step response with Tr=26 msec,Ts=54 msec, P.O. = 3.7\%, Ess=6.8x10-3 mm. The transducer possess thedesired linear response with a sensitivity of 34nm/Hz. Finally, the encoder circuitry successfully maps the millivolt output to a pulse frequency range of 1150Hz to 12.5kHz. Results from an integrated system test show that the sensor can successfully detect errors in trajectory tracking introducted by both phase lag and perturbations. By physically realizing the hypothesized core features of a biological muscle spindle in engineering hardware, we evoked the type of actuated sensor output seen in the biological muscle spindle, a widely utilized tool of biological motor control.}, contents = {141} } @inproceedings{BRL138, author = {B. Hannaford and J.H Ryu}, title = {Time Domain Passivity Control of Haptic Interfaces}, booktitle = {Proc. IEEE Intl. Conference on Robotics and Automation}, pages = {1863-1869}, address = {Seoul KOREA}, month = may, year = {2001}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep138.pdf}, abstract = {A patent pending, energy based, method is presented for controlling a haptic interface system to ensure stable contact under a wide variety of operating conditions. System stability is analyzed in terms of the time - domain definition of passivity. We define a "Passivity Observer" (PO) which measures energy flow in and out of one or more subsystems in real-time software. Active behavior is indicated by a negative value of the PO at any time. $<$P$>$We also define the "Passivity Controller" (PC), an adaptive dissipative element which, at each time sample, absorbs exactly the net energy output (if any) measured by the PO. The method is tested with simulation and implementation in the "Excalibur" haptic interface system. Totally stable operation was achieved under conditions such as stiffness greater than 100 N/mm or time delays of 15ms. The PO/PC method requires very little additional computation and does not require a dynamical model to be identified.}, contents = {138} } @inproceedings{BRL137, author = {B. Hannaford and J.H. Ryu and Y.S. Kim}, editor = {Margret McLaughlin}, title = {Stable Control of Haptics}, booktitle = {Touch in Virtual Environments: Proceedings USC Workshop on Haptic Interfaces,}, publisher = {Prentice Hall}, month = {Feb 23}, year = {2001}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep137.pdf}, abstract = {Humans interact with their surrounding environment through five sensory channels, popularly labeled "sight," "sound," "taste," "smell," and "touch." It is our sense of touch which provides us with much of the information necessary to modify and manipulate the world around us. The word haptic refers to something of or relating to the sense of touch: conveying information on physical properties such as inertia, friction, compliance, temperature, and roughness. This sense can be divided into two categories: the kinesthetic sense, through which we sense movement or force in muscles and joints; and the tactile sense, through which we sense shapes and textures. This chapter will focus on the stable control of devices and systems which support hap- tic interaction, especially relating to the use of kinesthetic sense in virtual environments.}, contents = {137} } @inproceedings{BRL136, author = {J. Dosher and G. Lee and B. Hannaford}, editor = {Margret McLaughlin}, title = {How low can you go? Detection thresholds for small haptic effects.}, booktitle = {Touch in Virtual Environments, Proceedings USC Workshop on Haptic Interfaces}, publisher = {Prentice Hall}, month = {Feb 23}, year = {2001}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep136.pdf}, abstract = {Can haptics be effective in low power and hand held applications? Inevitably a haptic device which meets the strict weight, power and volume requirements of a hand held device will be capable of only very small forces and displacements compared to existing desktop devices. This leads to two aspects to the question. What are the weakest haptic effects that can be effectively used by humans interacting with a haptic device? And how can haptic devices be designed to operate at or just above these low levels while maintaining both the weight, power and volume constraints and effective outputs? $<$p$>$ This paper will describe experiments involving exploration of 1-D surface profiles using a single finger in the flexion extension plane and the (Finger-tip Haptic Display) FHD, a 2 DOF, low friction, direct drive, planar haptic display capable of high fidelity representation of virtual surfaces. Using a forced-choice experiment incorporating an adaptive threshold algorithm, we measured the weakest haptic effects that are detectable via the haptic interface. In the first experiment, the subject is presented with two targets 5 mm wide, spaced 10 mm apart, and located on a horizontal line. The haptic force on one randomly chosen target consists of a tangential force beginning at each edge of the target, and pointing inward, toward the target center. We use the converged adaptive force threshold value as characteristic of the smallest detectable haptic effects that can be communicated by our specific haptic device (FHD) to a specific subject. Data for 7 subjects indicates an average human/machine threshold of 30 mN.}, contents = {136} } @article{BRL135, author = {J. Rosen and M. Solazzo and B. Hannaford and M. Sinanan}, title = {Objective Evaluation of Laparoscopic Surgical Skills Using Hidden Markov Models Based on Haptic Information and Tool/Tissue Interactions}, journal = {American College of Surgeons Annual Meeting - Washington State Chapter}, address = {Lake Chelan, WA}, month = jun, year = {2000}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep135.pdf}, abstract = {Laparoscopic surgical skills evaluation of surgery residents is usually a subjective process, carried out in the operating room by senior surgeons. By its nature, this process is performed using fuzzy criteria.The objective of the current study was to develop and assess an objectivelaparoscopic surgical skill scale using Hidden Markov Models (HMM) basedon haptic information, tool/tissue interactions and visual taskdecomposition. Methods: Eight subjects (six residents: first year surgical residents 2xR1, third year surgical residents 2xR3, fifth year surgical residents 2xR5; and two expert laparoscopic surgeons: 2xES) performed laparoscopic cholecystectomy following a specific 7 step protocolon a pig. An instrumented laparoscopic grasper equipped with a three-axisforce/torque sensor was used to measure the forces and torques at thehand/tool interface synchronized with a video of the tool operativemaneuvers. A synthesis of frame-by-frame video analysis was used to define14 different types of tool/tissue interactions, each one associated withunique force/torque (F/T) signatures. HMMs were developed for each subjectrepresenting the surgical skills in terms of haptic information andtool tissue interactions. The statistical distance between the HMMSrepresenting residents at different levels of their training and the HMMsof expert surgeons were calculated in order to evaluate the learning curveof selected steps of laparoscopic cholecystectomy. Results: The objectivelaparoscopic surgical skill learning-curve showed significant differencesbetween all skill levels. The major differences between skill levelswere: (i) magnitudes of F/T applied, (ii) types of tool/tissue interactionsused and with the transition between them, and (iii) time intervalsspent in each tool/tissue interaction and the overall completion time.The HMM analysis showed that the greatest difference in performance wasbetween R1 and R3 and then decreased as the level of expertise increased.The objective evidence for a learning curve indicates that the surgicalresidents appear to acquire a major portion of their laparoscopic surgicalcapabilities between the first and the third years of their residency training.}, contents = {135} } @article{BRL134, author = {J. Rosen and C. Richards and B. Hannaford and M. Sinanan}, title = {Hidden markov Models of Minimally Invasive Surgery}, journal = {Studies in Health Technology and Informatics - Medicine Meets Virtual Reality}, volume = {70}, pages = {279-285}, month = jan, year = {2000}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep134.pdf}, abstract = {A crucial process in surgical education is to evaluate the level of surgical skills. For laparoscopic surgery, skill evaluation is traditionally performed subjectively by experts grading a video of a procedure performed by a student. By its nature, this process is performed using fuzzy criteria. The objective of the current study was to develop and assess a skill scale using Discrete Hidden Markov Models (DHMM). Ten surgeons (5 Novice Surgeons - NS; 5 Expert Surgeons) performed a cholecystectomy and Nissen fundoplication in a porcine model. An instrumented laparoscopic grasper equipped with a three-axis force/torque sensor was used to measure the forces/torques at the hand/tool interface synthronized with a video of the tool operative maneuvers. A synthesis of frame-by-frame video analysis and a vector quantization algorithm, defined force/torque signatures for 14 types of tool/tissue interactions. From each stop of the surgical procedures, two DHMM were developed representing the performance of 3 surgeons randomly selected from the 5 in the ES and NS groups. The data obtained by the remaining 2 surgeons in each group were used for evaluating the performance scale. The final result was a surgical performance index which represented a ratio of statistical similarity between the examined surgeon's DHMM and the DHMM of NS and ES. The difference between the performance index value, for a surgeon under study, and the NS/ES boundary, was considered to indicate the level of expertise in the surgeon'sown group. Using the index, 87.5\% of the surgical procedures werecorrectly classified into the NS and ES groups. The 12.5\% of the proceduresthat were misclassified were performed by the ES and classified as NS.However, in these cases the performance index values were very close tothe NS/ES boundary. Preliminary data suggest that a performance indexbased on DHMM and force/torque signatures provides an objective means ofdistinguishing NS from ES. In addition, this methodology can be furtherapplied to evaluate haptic virtual reality surgical simulators forimproving realism in surgical education.}, contents = {134} } @inproceedings{BRL130, author = {T. Maneewarn and B. Hannaford}, title = {Augmented Haptics of Manipulator Kinematic Condition}, booktitle = {Proc. SPIE Telemanipulator Workshop}, address = {Boston, MA}, month = oct, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep130.pdf}, abstract = {This paper describes a study of whether haptic feedback can be used to represent information that is normally difficult to obtain via visual feedback in telerobotic system. Problems of manipulator kinematic condition such as singularity and joint limit have been well known for a long time. Kinematic condition of the manipulator is difficult to be recognized visually. Poor kinematic condition often causes trajectory error or other undesirable effects in the system. This problem is quite significant in telerobotics since a fully pre-planned path that completely excludes poor kinematic condition is usually not available. $<$p$>$ In this paper, the haptic representation for singularity and joint limit condition is introduced. The proposed haptic feedback allows the operator to be able to identify poor kinematic condition of the slave manipulator, and naturally recommends the suitable solution to the problem in real-time. Teleoperation experiment was conducted in order to validate and evaluate the proposed theoretical framework.}, contents = {130} } @article{BRL129, author = {G.K. Klute and J.M. Czerniecki and B. Hannaford}, title = {McKibben Artificial Muscles: Pneumatic Actuators with Biomechanical Intelligence}, journal = {IEEE/ASME 1999 Intl. Conf. on Advanced Intelligent Mechatronics}, address = {Atlanta GA}, month = {September 19-22}, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep129.pdf}, abstract = {This paper reports on the design of a biorobotic actuator. Biological requirements are developed from published reports in the muscle physiology literature whose parameters are extracted and used in a Hill muscle model. Data from several vertebrate species (rat, frog, cat, and human) are used to evaluate the performance of a McKibben pneumatic actuator. The experimental results show the force-length properties of the actuator are muscle-like, but the force-velocity properties are not. The design of a hydraulic damper with fixed orifices, placed in parallel with the McKibben actuator, is proposed to improve the force-velocity performance. Simulation results of this practical design indicate a significant improvement.}, contents = {129} } @article{BRL128, author = {R. Adams and D. Klowden and B. Hannaford}, title = {Stable Haptic Interaction Using the Excalibur Force Display}, journal = {IEEE Intl. Conf. on Robotics and Automation}, address = {San Francisco, CA}, month = apr, year = {2000}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep128.pdf}, abstract = {Creating a compelling haptic sense of immersion in a virtual environment is a challenging task for the control engineer. A haptic display must render both low impedance free-space motion and high impedance rigid constraints while ensuring stable interaction. This paper outlines a control design approach for the most common haptic display implementation, the impedance display. Two-port absolute stability criteria are used to develop explicit design bounds for virtual coupling networks which guarantee system stability for a broad class of human operators and virtual environments. The technique is applied to the Excalibur three-axis force display. The resulting absolutely stable haptic interface is the centerpiece of a Virtual Building Block simulation which emulates the behavior of LEGO TM bricks in a virtual environment.}, contents = {128} } @inproceedings{BRL126, author = {R. Adams and M. Moreyra and B. Hannaford}, title = {Excalibur, {A} Three-Axis Force Display}, booktitle = {ASME Winter Annual Meeting Haptics Symposium}, address = {Nashville, TN}, month = nov, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep126.pdf}, abstract = {In haptic simulation, a force feedback device is combined with a digital representation of a virtual world to create a kinesthetically immersive experience. The force feed-back device, or haptic display, is usually a robotic manipulator with which a human operator interacts physically, usually through a handle, stylus, finger-pad or some other form of customized interface. Modeling of the haptic display is often overlooked when building a haptic simulation. Understanding the dynamic behavior of the device is critical in assessing the stability and performance of the overall system as well as in the construction of the digital simulation. This paper describes some of the special modeling requirements for haptic displays. A dynamic model for Excalibur, a new three-axis force display, is developed in a two step process. First an analytical model is constructed based on measured values and basic principals. Then the model is tuned using the results of vibrational testing to achieve a close match between the modal behavior of the theoretical and real systems. Numerical and experimental results are presented for representative points in the device� workspace.}, contents = {126} } @inproceedings{BRL125, author = {T. Maneewarn and B. Hannaford and D. Storti and M. Ganter}, title = {Haptic Rendering For Internal Content Of An Implicit Object}, booktitle = {ASME Winter Annual Meeting Haptics Symposium}, address = {Nashville, TN}, month = nov, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep125.pdf}, abstract = {The haptic rendering algorithms for an object with implicit surface representation are proposed. The basic rendering algorithm for a regular two-dimensional manifold is used to represent a solid volumetric object. For applications where information about the internal content of an object is concerned, the haptic rendering algorithm for internal content of an implicit object is developed. The proposed algorithm is derived from the concept of state transition via �ort�using manifold with boundary representation. Manifold with boundary is constructed from implicit primitives. The advantage of implicit surface representation in haptic applications has been emphasized. Both algorithms were successfully implemented in the haptic interface system and were applied to various implicit models.}, contents = {125} } @inproceedings{BRL124, author = {J. Rosen J. and M. MacFarlane and C. Richards and B. Hannaford and C. Pellegrini and M. Sinanan}, title = {Surgeon/Endoscopic Tool Force-Torque Signatures In The Evaluation of Surgical Skills During Minimally Invasive Surgery}, booktitle = {Proceedings, MMVR-99 (Medicine Meets Virtual Reality)}, address = {San Francisco}, month = jan, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep124.pdf}, abstract = {The best method of training for laparoscopic surgical skills is controversial. Some advocate observation in the operating room, while others promote animal and simulated models or a combination of surgical related tasks. The mode of proficiency evaluation common to all of these methods has been subjective evaluation by a skilled surgeon. In order to define an objective means of evaluating performance, an instrumented laparoscopic grasper was developed measuring the force/torque at the surgeon hand/tool interface. The measured database demonstrated substantial differences between experienced and novice surgeon groups. Analyzing forces and torques combined with the state transition during surgical procedures allows an objective measurement of skill in MIS. Teaching the novice surgeon to limit excessive loads and improve movement efficiency during surgical procedures can potentially result in less injury to soft tissues and less wasted time during laparoscopic surgery. Moreover the force/torque database measured in this study may be used for developing realistic virtual reality simulators and optimization of medical robots performance.}, contents = {124} } @inproceedings{BRL123, author = {G.K. Klute and J. Czerniecki and B. Hannaford}, title = {Development of Powered Prosthetic Lower Limb}, booktitle = {Proc. 1st National Mtg, Veterans Affairs Rehab. R\&D Service}, address = {Washington, DC}, month = oct, year = {1998}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep123.pdf}, abstract = {(This publication is a poster)$<$br$>$ Objective: Improve below-knee amputee gait by developing a powered prosthetic limb with muscle-like actuators to provide the missing propulsive force of the ankle musculature. $<$p$>$ Research Plan: Develop actuators with muscle-like performance and incorporate them into a below-knee prosthetic limb. Once fabricated, we plan to test the hypotheses that such a device will: $<$p$>$$<$ul$>$ $<$li$>$(1) Reduce the metabolic costs of locomotion, $<$li$>$(2) Improve gait symmetry, and $<$li$>$(3) Reduce the perceived level of effort of amputee gait. $<$/ul$>$$<$p$>$ Methods: Use non-linear finite element methods and computer models incorporating fluid flow effects to develop lightweight, energy efficient actuators whose force-length-velocity characteristics mimic that of biological muscle as exemplified by the Hill muscle model. $<$p$>$ Findings: Eccentric and concentric test results for our current McKibben actuators reveal force-length characteristics similar to biological muscle. We seek to improve the velocity dependent characteristics by adding additional damping. Our computer models have led to specification of a miniature hydraulic damper whose force-velocity relationship is controlled by flow restricting orifices. Our work in progress includes fabricating and testing these new actuators. $<$p$>$ Clinical Relevance: Many prosthetic users exhibit lack of endurance, non-symmetrical gait, and high levels of effort while walking at self-selected rates. A powered lower limb prosthesis is expected to provide measurable gains in performance observable in clinical practice. The end result is patients who can walk farther, faster, and with less effort when compared to conventional prosthetic devices. $<$p$>$ This research was supported in part by Department of Veterans Affairs Center Grant A0806-C.}, contents = {123} } @inproceedings{BRL117, author = {M. Moreyra and B. Hannaford}, title = {A Practical Measure of Dynamic Response of Haptic Devices}, booktitle = {Proc. IEEE Intl. Conf. on Robotics and Automation}, address = {Leuven, Belgium}, month = may, year = {1998}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep117.pdf}, abstract = {A method is described to characterize and experimentally measure the dynamic performance of haptic display devices. The method characterizes the response to impulse inputs of various frequencies characteristic of simulating hard contacts in virtual environments. By comparing the experimentally measured velocity just after the impulse with the actual velocity, a dimensionless measure of structural distortion is derived. The method is easy to apply because no additional sensors or test fixtures are required. This paper presents a derivation of the structural deformation ratio for the single degree of freedom case, generalization to N-dof spatial devices, and experimental results for a single axis of a rugged haptic device in our laboratory.}, contents = {117} } @inproceedings{BRL116, author = {G. Klute and B. Hannaford}, title = {Fatigue Characteristics of McKibben Artificial Muscle Actuators}, booktitle = {Proceedings. IROS-98}, pages = {1776-82}, address = {Victoria, B.C., Canada}, month = nov, year = {1998}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep116.pdf}, abstract = {The McKibben artificial muscle is a pneumatic actuator whose properties include a very high force to weight ratio. This characteristic makes it very attractive for a wide range of applications such as mobile robots and prosthetic appliances for the disabled. Typical applications often require a significant number of repeated contractions and extensions or cycles of the actuator. This repeated action leads to fatigue and failure of the actuator, yielding a life span that is often shorter than its more common robotic counterparts such as electric motors or pneumatic cylinders. In this paper, we develop a model that predicts the maximum number of life cycles of the actuator based on available uniaxial tensile properties of the actuator's inner bladder. Experimental results, which validate the model, reveal McKibben actuators fabricated with natural latex rubber bladders have a fatigue limit 24 times greater than actuators fabricated with synthetic silicone rubber at large contraction ratios.}, contents = {116} } @inproceedings{BRL115, author = {R. Adams and M. Moreyra and B. Hannaford}, title = {Stability and Performance of Haptic Displays: Theory and Experiments}, booktitle = {Proceedings of the ASME Winter Annual Meeting Haptics Workshop}, month = nov, year = {1998}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep115.pdf}, abstract = {In haptic simulation, a human operator kinesthetically explores a virtual environment. To achieve a virtual sense of touch, the human interacts with an active mechanical device, called a haptic display. This paper presents an approach to guarantee that this physical man-machine interface remains stable, while maximizing performance. The key element in ensuring stability is the virtual coupling network, an artificial link between the haptic display and the virtual environment. Considerations of structural flexibility in the haptic device are included in the derivation of design criteria for such networks. Solutions for both the impedance and admittance models of haptic interaction are included. Numerical and experimental results for a two degree-of-freedom haptic display demonstrate the effectiveness of the proposed approach in achieving performance and stability in haptic simulation.}, contents = {115} } @inproceedings{BRL114, author = {T. Maneewarn and B. Hannaford}, title = {Haptic Feedback of Kinematic Conditioning for Telerobotic Applications}, booktitle = {Proceedings of IROS 98}, pages = {1260-65}, address = {Victoria, B.C., Canada}, month = nov, year = {1998}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep114.pdf}, abstract = {Kinematic conditioning at singularity is the problem where small motions in cartesian space cause excessive joint velocities. This problem is significant in teleoperation. Haptic feedback provides the bi-directional flow of information which allows the operator to control the telerobot interactively. Haptic representation of kinematic singularity is proposed as a new approach to achieve better performance in telerobotic control near kinematic singularities. Four different singularity force feedback methods are defined and studied. Experimental results with a force feedback Master and simulated Slave system show that teleoperation performance near singular configurations was affected and improved by using singularity force feedback.}, contents = {114} } @inproceedings{BRL113, author = {R. Adams and B. Hannaford}, title = {A Two-Port Framework for the Design of Unconditionally Stable Haptic Interfaces}, booktitle = {Proceedings of IROS 98}, pages = {1254-59}, address = {Victoria, B.C., Canada}, month = nov, year = {1998}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep113.pdf}, abstract = {A haptic interface is a kinesthetic link between a human operator and a virtual environment. This paper addresses stability and performance issues associated with haptic interaction. It generalizes and extends the concept of a virtual coupling network, an artificial connection between a haptic display and a virtual world, to include both the impedance and admittance models of haptic interaction. A benchmark example exposes an important duality between these two cases. Linear circuit theory is used to develop necessary and sufficient conditions for the stability of a haptic simulation, assuming the human operator and virtual environment are passive. These equations lead to an explicit design procedure for virtual coupling networks which give maximum performance while guaranteeing stability. By decoupling the haptic display control problem from the design of virtual environments, the use of a virtual coupling network frees the developer of haptic-enabled virtual reality models from issues of mechanical stability.}, contents = {113} } @inproceedings{BRL111, author = {B. Hannaford and J. Trujillo and M. Sinanan and M. Moreyra and J. Rosen and J. Brown and R. Lueschke and M. MacFarlane}, title = {Computerized Endoscopic Surgical Grasper}, booktitle = {Proceedings, MMVR-98 (Medicine Meets Virtual Reality), San Diego}, month = jan, year = {1998}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep111.pdf}, abstract = {We report a computerized endoscopic surgical grasper with computer control and a force feedback (haptic) user interface. The system uses standard unmodified grasper shafts and tips. The device can control grasping forces either by direct surgeon control, via teleoperation, or under software control. In this paper, we test an automated palpation function in which the grasper measures mechanical properties of the grasped tissue by applying a programmed series of squeezes. Experimental results show the ability to discriminate between the normal tissues of small bowel, lung, spleen, liver, colon, and stomach. We anticipate applications in telesurgery, clinical endoscopic surgery, surgical training, and research.}, contents = {111} } @inproceedings{BRL108, author = {B. Hannaford and J. Hewitt and T. Maneewarn and S. Venema and M. Appleby and R. Ehresman}, title = {Telerobotic Macros for Remote Handling of Protein Crystals}, booktitle = {Proceedings Intl. Conf. on Advanced Robotics, (ICAR97)}, address = {Monterrey, CA}, month = jul, year = {1997}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep108.pdf}, abstract = {A combined University / Industry team has developed a prototype system for handling protein crystals aboard the space station. This systemuses a miniature direct drive robot, CCD television cameras, and a client-server computing system using internet protocols to support the capture of protein crystals from aqueous growth solutions. The system was demonstrated between Huntsville AL. and Seattle WA. An operator in Huntsville controlled the mini robot by invoking pre-defined relative and absolute macro files. A set of movement macros (a predefined sequence of multi-device movement commands) were developed to support precision motion between task locations in the glovebox. The operator can invoke the macros by clicking icons in the remote control interface. The system is a promising start for the development of a space-station based remote protein crystal analysis facility.}, contents = {108} } @inproceedings{BRL107, author = {B. Hannaford and J. Hewitt and T. Maneewarn and S. Venema and M. Appleby and R. Ehresman}, title = {Telerobotic Remote Handling of Protein Crystals}, booktitle = {IEEE International Conference on Robotics and Automation}, address = {Albuquerque, NM}, month = apr, year = {1997}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep107.pdf}, abstract = {A combined University / Industry team has developed a prototype system for handling protein crystals aboard the space station. This system uses a miniature direct drive robot, CCD television cameras, and a client-server computing system using internet protocols to support the capture of protein crystals from aqueous growth solutions. The system was demonstrated between Hunstville AL. and Seattle WA. An operator in Huntsville controlled the mini robot by invoking pre-defined relative and absolute macro files. The operators observed results using video images sent through the internet link using CuSeeMe video conferencing software. In 3 of 4 trials, the operators successfully captured 0.5mm simulated protein crystals into a glass capillary. The system is a promising start for the development of a space-station based remote protein crystal analysis facility.}, contents = {107} } @inproceedings{BRL102, author = {P.J. Laughlin and J.W. Pitton and B Hannaford}, title = {Fast Approximations to Positive Time-Frequency Distributions with Applications}, booktitle = {Proceedings 1995 International Conference on Acoustics, Speech, and Signal Processing}, volume = {2}, pages = {1009-12}, address = {Detroit}, month = may, year = {1995}, abstract = {We present a general approach to approximating positive time- frequency distributions (TFDs) through nonlinear combinations of spectrograms. Closed-form solutions for the combinations are obtained via optimization of entropy functionals subject to an energy constraint. We apply two such combinations to generating approximate TFDs for whale sounds and speech. Through these applications, it can be seen that these methods give results superior to that achieved with individual spectrograms, and remarkably close to the positive TFDs obtained via computationally-intensive methods.}, contents = {102} } @inproceedings{BRL101, author = {P. Buttolo and R. Oboe and B. Hannaford and W. McNeely}, title = {Force Feedback in Shared Virtual Simulations}, booktitle = {Proceedings MICAD}, address = {Paris}, year = {1996}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep101.pdf}, abstract = {Virtual reality is a powerful tool for training, simulation and computer aided design. Replacing the traditional mouse with a force feedback device might enhance the performance of such systems, permitting a more natural interaction. The software interface and the mechanical design of force-feedback devices is critical. The operative system must be real time and guarantee low latency and high sampling rate. Additional constraints are introduced if there is a need for sharing the simulation among multiple players. In this paper we will present two haptic devices, and a distributed architecture that allows operators to manipulate objects in a shared virtual environment. We will conclude with two examples, a multi-player squash game and a shared force-feedback CAD system for airplane manufacturing.}, contents = {101} } @inproceedings{BRL099, author = {S. Venema and B. Hannaford}, title = {Miniature Telerobots in Space Applications}, booktitle = {Proc. Int. Conf. on Integrated Micro-Nanotechnology for Space Applications}, address = {Houston Tx.}, month = oct, year = {1995}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep099.pdf}, abstract = {Ground controlled telerobots can be used to reduce astronaut workload while retaining much of the human capabilities of planning, execution, and error recovery for specific tasks. Miniature robots can be used for delicate and time-consuming tasks such as biological experiment servicing without incurring the significant mass and power penalties associated with larger robot systems. However, questions remain regarding the technical and economic effectiveness such mini-telerobotic systems. This paper addresses some of these open issues and the details of two projects which will be able to provide some of the needed answers. The Microtrex project is a joint University of Washington/NASA project which plans on flying a miniature robot as a Space-shuttle experiment to evaluate the effects of microgravity on ground controlled manipulation while subject to variable time-delay communications. A related project involving the University of Washington and Boeing Defense and Space will evaluate the effectiveness of using a minirobot to service biological experiments in a space station experiment "glove-box" rack mock-up, again while subject to realistic communications constraints.}, contents = {099} } @inproceedings{BRL098, author = {P. Buttolo and B. Hannaford}, title = {Advantages of Actuation Redundancy for the Design of Haptic Displays}, booktitle = {Proceedings, ASME Fourth Annual Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems}, volume = {DSC-57-2}, pages = {623-630}, address = {San Francisco}, month = nov, year = {1995}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep098.pdf}, abstract = {In this paper we will describe a direct-drive, actuation redundant, parallel manipulator, characterized by very low inertia, no backlash, and almost zero friction. We will then describe the problems and advantages of actuation redundancy and we will introduce a computationally-efficient algorithm that maximizes the force capability of the device. Actuation redundancy is different from kinematic redundancy because it concerns only the determination of forces and moments. A drawback of the parallel redundant structure is the high computational requirement. On the other hand, the possibility to choose the torque adopting a proper set of criteria permits satisfaction of a desired set of requirements for haptic devices, such as maximize the force output and achieve a homogenous force output in the workspace.}, contents = {098} } @inproceedings{BRL097, author = {B. Hannaford and A.K. Bejczy and P. Buttolo and M. Moreyra and S. Venema}, title = {Mini-Teleoperation Technology for Space Research}, booktitle = {Procedings International Symposium on Microsystems Intelligent Materials and Robots (MIMR-95)}, pages = {524-527}, address = {Sendai, Japan}, month = sep, year = {1995}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep097.pdf}, abstract = {A small direct drive serial manipulator has been developed for applications in sample handling for scientific payloads in space. The manipulator is about 15 cm in length, and has 5-10 microns positioning precision. The prototype forms the basis for design of the MicroTrex flight experiment for NASA. The experiment will measure performance of the robot in low earth orbit under control from a ground station. This paper describes the design of the manipulator, some experimental results of the manipulator performance, and plans for space flight testing.}, contents = {097} } @inproceedings{BRL096, author = {P. Buttolo and D. Kung and B. Hannaford}, title = {Manipulation in Real, Virtual, and Remote Environments}, booktitle = {Proceedings, IEEE International Conference on Systems, Man, and Cybernetics}, address = {Vancouver, BC}, month = oct, year = {1995}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep096.pdf}, abstract = {In this paper we describe a novel experimental procedure for the evaluation of a telemanipulator performance. A group of subjects performed the same set of tasks directly on a physical setup, on a virtual implementation capable of providing visual and force feedback through an haptic display, and remotely on the real setup using a telemanipulation system. Using this experimental procedure we were able to decouple the effects on the overall telemanipulator performance introduced by the single components of the system, master manipulator, display, slave manipulator and bilateral controller.}, contents = {096} } @inproceedings{BRL094, author = {P. Buttolo and D. Kung and B. Hannaford}, title = {Manipulation in Real, Virtual, and Remote Environments}, booktitle = {Video Proceedings, IEEE VRAIS-95}, address = {Raleigh, NC}, month = mar, year = {1995}, abstract = {In this video we present an operator performing the same set of tasks directly on a physical setup, on a virtual implementation capable of providing visual and force feedback through an haptic display, and remotely on the real setup using a telemanipulation system. The video provides a close look to two of the manipulators implemented in our laboratory, the minirobot and the penbased force display.}, contents = {094} } @inproceedings{BRL092, author = {S. Venema and B. Hannaford}, title = {Kalman Filter Based Calibration of Precision Motion Control}, booktitle = {Proceedings of IROS-95}, address = {Pittsburg, PA}, year = {August 95}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep092.pdf}, abstract = {A method is described and validated for the automatic calibration of analog sine-wave quadrature sensors, such as optical encoders, embedded in a functioning system. The algorithm uses a Kalman filter to estimate the true position of the direct-drive actuated joint using a model of it's dynamics, an applied actuator command, and measurements from the uncalibrated sensor. From the estimated true position, a lookup table is constructed which corrects sensor errors. Our results indicate that this method achieve accuracies typical of interferometric calibration, without requiring an external measurement device. The accuracy is surprisingly robust to modeling errors.}, contents = {092} } @inproceedings{BRL089, author = {P. Buttolo and B. Hannaford}, title = {Pen Based Force Display for Precision Manipulation of Virtual Environments}, booktitle = {Proceedings VRAIS-95}, pages = {217-225}, address = {Raleigh, NC}, month = mar, year = {1995}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep089.pdf}, abstract = {In this paper we describe the structure of a force display recently implemented for precision manipulation of scaled or virtual environments. We discuss the advantages of direct-drive parallel manipulators over geared serial manipulators for human-robot interaction application and introduce the serial-parallel structure we chose for our robot which interfaces with the human operator either at the fingertip or at the tip of a freely held pen-like instrument. We derive the statics and the dynamics, and then introduce the optimization criteria that allowed us to choose the dimensional parameters for the force display. Finally we show some of the potential application for this device that will be the subject of following papers.}, contents = {089} } @article{BRLTh013, author = {P.H. Marbot}, title = {Ia Response of a Mechanical Spindle Replica}, journal = {Ph.D. Dissertation}, publisher = {University of Washington, Department of Electrical Engineering}, month = mar, year = {1995}, abstract = {The research presented here describes and tests a prototype active measurement system which is designed to function as closely as possible to the human muscle spindle. The mechanical spindle will fulfill the nee dof the Anthroform Arm Project for a position sensor and will be placed in paralell with McKibben Artificial Muscle actuators. The goal is to make a functional equivalent to the human spindle. The mechanical spindel is comprised of a mechancial device and software devices which complement the mechanical device where and when it is insufficient to model the real spindle. The device consists of a non-linear loadcell, offset actuator, and electronics. The dimensions are 1cm x 1cm x 8cm and the response of the device is a good representation of actual spindle responses as defined by the leading published mathematical models of muscle spindles.}, contents = {Th013} } @article{BRLTh014, author = {N.E. Greivell}, title = {The Design of a Ferrofluid Magnetic Pipette}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = jun, year = {1995}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th014.pdf}, abstract = {New technological demands have motivated the search for methods of handling volumes of liquid smaller than 0.2 microliters. This thesis project addresses the problem of handling submicroliter liquid volumes smaller than 0.1 microliter. We have implemented a pipet utilizing ferrofluidics to handle submicroliter volumes. The slug of ferrofluid acts as the plunger as in a conventional mechanical pipet. To sample a small amount of fluid, the electromagnets are used to actuate a position change of the ferrofluid similar to conventional pipets which aspirate and dispense liquids by changing the position of the plunger. $<$p$>$ Mathematical models used to estimate the performance of the pipet are presented in Chapter 2. These models form the theoretical basis of ferrofluidics and magnetism as it applies to the ferrofluid-magnetic pipet. Experimentally measured performance data and the comparison of the data with the model's prediction are also presented.}, contents = {Th014} } @article{BRLTh015, author = {D.Y. Hwang}, title = {Teleoperation Performance with a Kinematically Redundant Slave Robot}, journal = {Ph.D. Dissertation}, publisher = {University of Washington, Department of Electrical Engineering}, month = dec, year = {1995}, abstract = {In this dissertation, two topics are presented: 1) scaled teleoperation system stability, 2) teleoperation with kinematic redundancy. $<$p$>$ When the scaled teleoperation is used, the stability issue becomes important due to the high gains in position or force scaling. We used two experimental methods to identify the stable region of position and force scaling factors of a one-axis system haveing 4000:1 force scaling capability. We used a simple classical teleoperation control law. An indirect closed loop approach with ARX technique was used to model the nonlinear slave system with a flexible printed circuit cable. The stability regions were identified by experiments and simulations. Then the slave system was physically linearized by replacing the flexibile printed circuit cable with thin wires. The linear case stability regions were identified. In addition, the contact stability region and sensitivity analysis were studied. $<$p$>$ Kinetic energy minimization was used to resolve the redundant joint space solution in the early literature work by Whitney in 1969. Kinetic energy optimization has been used for local and global redundancy control. However, the further effects of kinetic energy on teleoperation performance have not been studied. This section shows the effects of kinetic energy level on teleoperation performance. First, we expressed an inertia weighted pseudo-inverse solution corresponding to a general level of kinetic energy by using the gradient projection method. Second, we added joint limit avoiding by using the null space of the main task. Then we derived three kinematic redundancy control modes having different kinetic energy levels using the property of the generalized inverse matrix: "Whitney Mode", "Intermediate Mode", and "Least Squares" mode. $<$p$>$ To validate our algorithms, we performed autonomous robot tests and teleoperation. The tradeoff between kinetic energy level and joint limit index was clearly shown in the autonomous test. For teleoperation, 4 tasks and 7 indices were defined. A 3-DOF pen-based master and 5-DOF Mini Direct Drive Robot were used. Tasks were x-y-z positioning and contact, giving 2 DOF kinematic redundancy in the slave robot. Overall, the "Whitney Mode" showed the best performance, while the least-squares mode showed the worst performance. In addition, the subjective quality ratings of inertia force, bias force, noise force were made by the test operators. "Whitney Mode" showed the lowest perceived level of noise force.}, contents = {Th015} } @article{BRLTh016, author = {P. Buttolo}, title = {Characterization of Human Pen Grasp with Haptic Displays}, journal = {Ph.D. Dissertation}, publisher = {University of Washington, Department of Electrical Engineering}, month = jun, year = {1996}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th016.pdf}, abstract = {Throughout this thesis we have, theoretically and experimentally, analyzed various properties of pen grasp interaction. We showed that to experimentally measure the mechanical impedance of the human hand we need a haptic device with specific characteristics, such as low inertia, almost zero friction and very high stiffness. Part of the research activity was devoted into designing a haptic device that would satisfy these stringent requirements. Using a theoretical model and experimental data we found that pen grasp manipulation is superior to single finger manipulation, both in terms of mechanical impedance and accuracy of motion control. Moreover, because of its parallel structure, the pen grasp stiffness ellipse is not very sensitive to changes in the kinematic configuration. $<$p$>$ The haptic display can be tuned to a specific user and task introducing an additional term in the device controller. The stiffness and damping ellipses can be enlarged, rotated, and their shape altered, so that better rejection to disturbance while executing precise motion control can be achieved. However we discovered that the potential benefits are limited by the natural performance of the device itself, since simulating dynamic elements, such as springs and dampers, introduces noise into the system. Our analysis was just a preliminary test and much more remains to be done. $<$p$>$ We analyzed four different types of grasp, with particular attention to four-fingered grasps, and found similar stiffness ellipses for all of them. Some of these grasps were chosen observing different people interacting with a pen, others by trying different configuration on a custom computer animated model.}, contents = {Th016} } @article{BRLTh017, author = {C.P. Chou}, title = {Study of Human Motion Control with a Physiologically Based Robotic Arm and Spinal Level Neural Controller}, journal = {Ph.D. Dissertation}, publisher = {University of Washington, Department of Electrical Engineering}, month = jun, year = {1996}, annote = {http://brl.ee.washington.edu/people/ccp/phd.pdf}, abstract = {The goals of this research are: 1) to apply knowledge of human neuro-musculo-skeletal motion control to build a physiology based neural controller and biomechanics based "anthroform" robotic arm system, and 2) to utilize the neural controller and anthroform arm system to study some controversial issues and to predict new phenomena of the human motion control system. A physiologically analogous artificial neural network controller, a feed-forward controller, and two anatomically accurate robotic arms (the Anthroform Arm and the testing elbow) are implemented and applied in this study. In order to build the physical arm systems to have mechanical properties as close as possible to the human arm, McKibben pneumatic artificial muscles, force sensors, and mechanical muscle spindles are integrated in the systems with anatomically accurate muscle attachment points. $<$p$>$ In addition, the neural controller emulates the behavior of spinal segmental reflex circuitry in real time, which includes motoneurons, interneurons, and Ia and Ib afferent feedbacks. The feed-forward controller emulates the inverse kinematics and inverse dynamics functions of higher central nervous system to convert conceptual movement parameters to spinal neural activation patterns. $<$p$>$ Systematic experiments of elbow posture maintenance and voluntary fast flexion movement are performed and compared to physiological experimental data. New experiments are performed in which responses to torque perturbation are measured when selected afferent pathways are blocked. A "covariance diagram" is introduced. And a linear model is used to help to analyze the roles of system components and the stability. The results show: 1) the neural controller and testing elbow system is capable of similar performance in posture maintenance as the human elbow. 2) Muscle co-contraction and Ia afference with gamma motoneuron excitation are two effective ways to increase joint stiffness and damping, which in turn reduces the mechanical sensitivity of the joint to external perturbation and shorten the settling time of the system. 3) Feed-forward inverse dynamics information is important to performing voluntary fast movement. And 4) feedback delay limits the maximum loop gain of the closed-loop controlled system to maintain stability and still produce enough additional torque to resist external perturbations during voluntary movement. A higher level "nearly open loop" predictive feedback mechanism is proposed for solving this high-loop-gain instability problem. Physiological experiments are encouraged to verify the above phenomena in the future.}, contents = {Th017} } @article{BRLTh018, author = {H. Takenaka}, title = {Hidden Markov Model Approach to Skill Analysis in Violin Bowing}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = dec, year = {1995}, abstract = {Human Skill is an ability to perform a given task precisely in a suitable period. Skill consists of two categories, mental skill and motor skill. Skill acquisition has been on of the most important research areas in the fields of robotics, rehabilitation, and sports. One such skill is violin bowing whose methods for teaching have changed little over the years. This thesis investigates the possible development of a bowing motion analysis and training system based on optical position tracking of arm movement and Hidden Markov Modeling (HMM) of the movement data. A HMM is used to descriminate between two different types of bowing motions recorded with an optical motion analysis system. $<$p$>$ The results showed that the HMM is capable of discriminating Legato from Staccato bowing, but that standard training algorithms do not improve performance.}, contents = {Th018} } @article{BRLTh019, author = {M. Moreyra}, title = {Design of a Planar High Bandwidth Force Display with Force Sensing}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = aug, year = {1996}, abstract = {The design of a planar high bandwidth force display and its force sensor are described. A simplified model of the dynamic characteristics, including fast dynamics, was formulated and analyzed. A controller, in which the contact forces were amplified using actuators, was implemented for reducing the force a user requires for driving the end effector. The analysis indicated that the closed-loop control system was conditionally stable. The system became unstable for force gains larger than two. Qualitative analysis showed that by increasing the mechanical damping, the performance of the closed-loop system could be improved. Experimental results showed that the average forces for moving the handle in free space were reduced to one sixth when using the force sensor based controller, similarly, the typical peak forces were reduced to one third. Measurements of contact forces versus commanded forces on the HBFD during elastic collisions were performed. This measurements showed that the mechanical transmission of}, contents = {Th019} } @article{BRLTh020, author = {J.M. Trujillo}, title = {Enhancing the Sense of Touch in Minimally Invasive Surgery: Design of the Force Reflective Endoscopic Grasper}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = jun, year = {1997}, abstract = {The design of a one degree of freedom force reflecting surgical grasping device is detailed. This device has been designed specifically for the task of increasing the haptic sensations available to the surgeon during minimally invasive procedures, making use of existing surgical tool technology. Modified voice coil actuators from 5.25 inch disk drives provided the driving forces. The bilateral position error-based controller was designed for a linear model of the master and slave subsystems. Subjective haptic considerations influenced the controller design. Laboratory testing of in-vivo organ tissue is presented and an investigation of the variable stiffness of various soft tissue samples is detailed. The device achieves the stated goal of enhancing the haptic sensation encountered in minimally invasive surgical procedures and enables an expert surgeon to discriminate different material samples.}, contents = {Th020} } @article{BRLTh021, author = {S.C. Venema}, title = {Experiments in Surface Perception Using a Haptic Display}, journal = {Ph.D. Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = apr, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th021.pdf}, abstract = {A haptic display provides the mechanical analog of a physical environment for our sense of touch in a virtual reality (VR) simulation system. In this dissertation, we explore the design and implementation of a planar fingertip haptic display (FHD) mechanism. We first present a new technique for analysing the reachable workspace of mechanisms that have stochastic kinematic parameters. This technique is used to develop a stochastic representation of the reachable workspace of the human finger. Using this finger workspace, we present a method for selecting the kinematic parameters of a five-bar linkage mechanism to match the finger workspace while providing high-quality force output capability over the entire mechanism workspace. We then use this haptic display in psychophysical experiments which explore the human perception of geometric surface discontinuities on a haptically rendered virtual surface. Specifically, the experiments examine how the ability to perceive and locate both first-order and second-order surface discontinuities is affected by both the magnitude of the discontinuity and by the particular set of control gains used in haptically rendering the discontinuity. The results of these experiments are relevant to haptic simulation systems which approximate complex curved surfaces with planar facets: the intersection between facets is a form of surface discontinuity and the perceived smoothness of the surface is likely related to the magnitude of the change in surface gradient at these intersections.}, contents = {Th021} } @article{BRLTh022, author = {R. J. Adams}, title = {Stable Haptic Interaction with Virtual Environments}, journal = {Ph.D. Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = sep, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th022}, abstract = {Two-port absolute stability criteria are used to develop explicit control law design bounds for three detailed haptic display implementations: the basic impedance display, the impedance display with force compensation, and the admittance display. The strengths and weaknesses of each approach are illustrated through numerical and experimental results for two different haptic devices: the planar High Bandwidth Force Display and the Excalibur three-axis force display. The examples highlight the ability of the proposed design approach to handle some of the most difficult problems in control law synthesis for haptics, including structural flexibility and non-collocation of sensors and actuators. Good agreement is observed between theoretically predicted and experimental results. $<$p$>$ An absolutely stable haptic interface, designed using these methods, is the centerpiece of a Virtual Building Block training study. This study investigates the benefits of haptic feedback for training a manual task in a virtual environment. Three groups of test operators are exposed to different treatments before being asked to build a LEGO�biplane model: virtual training with force feedback, virtual training without force feedback, and no training. Results show training with haptic feedback has a significant impact on performance in the manual real-world task.}, contents = {Th022} } @article{BRLTh023, author = {T. Maneewarn}, title = {Haptic Feedback of Manipulator Kinematic Conditioning for Teleoperation}, journal = {Ph.D. Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = sep, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th023}, abstract = {In teleoperation, problems can occur when a slave manipulator loses the ability to move or exert force in some directions/orientations due to its configuration. The configuration near and at a manipulator s kinematic singularity can cause failure in the control algorithm and may result in the loss of kinesthetic correspondence between the operator and the slave manipulator. Haptic interface is bi-directional and yields small response time. Therefore the manipulator kinematic conditioning information can be presented to the operator more effectively using haptic feedback than the conventional visual feedback during real-time teleoperation. Singularity force feedback (SFF) is proposed to be an interactive solution to the singularity problem. SFF exists only in the neighborhood of singularity. SFF is created to reduce the command velocity in the critical direction and to guide the command motion to the feasible direction near a singularity. A procedural scheme for assigning the appropriate value of the parameters in SFF calculation is established. The proposed SFF model is analyzed in term of stability, passivity and error convergence. Teleoperation experiment is performed to validate the concept of SFF. The results from the experiment demonstrate that haptic feedback can effectively convey information about kinematic conditioning of a slave manipulator to the operator in real-time teleoperation. The proposed SFF method can improve the kinematic performance of teleoperation near singularity.}, contents = {Th023} } @article{BRLTh024, author = {G.K. Klute}, title = {Artificial Muscles: Actuators for Biorobotic Systems}, journal = {Ph.D. Thesis}, publisher = {University of Washington, Department of Bioengineering}, month = dec, year = {1999}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th024.pdf}, abstract = {Biorobotic research seeks to develop new robotic technologies based on the performance of human and animal neuromuscular systems. The development of one component of a biorobotic system, an artificial muscle and tendon, is documented here. The device is based on known static and dynamic properties of biological muscle and tendon which were extracted from the literature and used to mathematically describe the unique force, length, and velocity relationships. As biological tissue exhibits wide variation in performance, ranges are identified which encompass typical behavior for design purposes. $<$p$>$ The McKibben pneumatic actuator is proposed as the contractile element of the artificial muscle. A model is presented that includes not only the geometric properties of the actuator, but also the material properties of the actuator s inner bladder and frictional effects. Experimental evidence is presented that validates the model and shows the force-length properties to be muscle-like, while the force-velocity properties are not. The addition of a hydraulic damper is proposed to improve the actuator s velocity-dependent properties, complete with computer simulations and experimental evidence validating the design process. Furthermore, an artificial tendon is proposed to serve as connective tissue between the artificial muscle and a skeleton. A series of experimental tests verifies that the design provides suitable tendon-like performance. $<$p$>$ A complete model of the artificial musculo-tendon system is then presented which predicts the expected force-length-velocity performance of the artificial system. Based on the model predictions, an artificial muscle was assembled and subjected to numerous performance tests. The results exhibited muscle-like performance in general: higher activation pressures yielded higher output forces, faster concentric contractions resulted in lower force outputs, faster eccentric contractions produced higher force outputs, and output forces were higher at longer muscle lengths than shorter lengths. Furthermore, work loop tests used to experimentally measure the sustained work output during typical stretch-shortening cycles indicate the capacity to perform work increases with the magnitude of activation and is a function of both velocity and activation timing.}, contents = {Th024} } @article{BRLTh025, author = {K.N. Jaax}, title = {A Robotic Muscle Spindle: Neuromechanics of Individual and Ensemble Response}, journal = {Ph.D. Thesis}, publisher = {University of Washington, Department of Bioengineering}, month = jun, year = {2001}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th025.pdf}, abstract = {A mechatronic structural model of the mammalian muscle spindle Ia response was developed and used to investigate neuromechanical mechanisms contributing to individual spindle dynamics and the information content of spindle ensemble response. Engineering specifications were derived from displacement, receptor potential and Ia data in the muscle spindle literature, allowing reproduction of core muscle spindle behavior directly in hardware. A linear actuator controlled by a software muscle model replicated intrafusal contractile behavior; a cantilever-based transducer reproduced sensory membrane depolarization; a voltage-controlled oscillator encoded strain into a frequency signal. Results of engineering tests met all performance specifications. Data from the biological literature was used first to tune the model against 5 measures of ramp and hold response, then to validate the fully tuned model against ramp and hold, sinusoidal and fusimotor response experiments. The response with dynamic or static fusimotor input was excellent across all studies. The passive spindle response matched well in 5 of 9 measures. Dynamic intramuscular strain data from 28 locations on the surface of a contracting rat medial gastrocnemius was sent sequentially through the model to reconstruct the Ia ensemble response of a large population of muscle spindles. Results showed that under dynamic fusimotor stimulation, the ensemble significantly increased Ia correlation to whole muscle kinematic inputs and that homogeneously distributed dynamic fusimotor stimulation increased Ia ensemble correlation to muscle velocity in a dose-dependent manner. Proposed mechanisms include decorrelation of spindle noise by intramuscular strain inhomogeneities and fusimotor-dependent noise and nonlinear gains, as well as fusimotor-dependent velocity selectivity. Potential applications for the robotic model include basic science motor control research and applied research in prosthetics and robotics.}, contents = {Th025} } @article{BRLTh026, author = {J. Dosher}, title = {Detection Thresholds and Performance Gains for Small Haptic Effects}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = dec, year = {2002}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th026.pdf}, abstract = {This research investigated detection thresholds for small haptic effects and the use of small haptic effects to improve task performance. The affects of icon representation, namely amplitude, shape, and pulse duration on haptic perception were studied. An adaptive thresholding method was used to obtain detection measurements for actively explored haptic icons ranging is size from 3 to 5 mm, smooth vs rough actively explored icons, and static icons of 100 to 150 ms pulse duration. Using Fitts' law as a measurement of task performance, the affects on subject performance with three levels of haptic stimulus between 50 to 300 mN are reported. Results indicate that rough (saw-tooth) haptic icons are more easily detected by a human subject than smooth (sinusoidal) icons of the same size, by almost a factor of two. Mean subject performance, as measured by Fitts' information processing rate and clicks-per-minute, improved with the amplitude of haptic stimulus.}, contents = {Th026} } @article{BRLTh027, author = {J.D. Brown}, title = {In-Vivo and Postmortem Biomechanics of Abdominal Organs Under Compressive Loads: Experimental Approach in a Laparoscopic Surgery Setup}, journal = {Ph.D. Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = dec, year = {2003}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th027.pdf}, abstract = {In order to provide realistic haptic (touch) feedback, simulators must incorporate accurate computational models of the in-vivo mechanical behavior of soft tissues. It is important to test tissues in surgically relevant ranges of applied force, duration, and deformation. In order to determine these ranges, a system known as the Blue DRAGON has been created that can track the motions of and the forces applied to surgical tools during live procedures. Thirty-one surgeons of varying skill were recorded performing three different surgical tasks. The mean force applied to the tool handles during tissue grasps was 8.52 N ± 2.77 N. Ninety-five percent of the handle angle frequency content was below 1.98 Hz ± 0.98 Hz. Average grasp time was 2.29 s ± 1.65 s, and 95\% of all grasps observed were held for less than 8.86 s ± 7.06 s. The average maximum grasp time performed by surgeons during these tasks was 13.37 s ± 11.42 s. $<$p$>$ Using these values as design parameters, a computer-controlled, motorized endoscopic grasper (MEG) has been designed to obtain biomechanical properties of soft tissues in-vivo. The MEG uses a geared DC motor to drive a Babcock grasper using a cable-and-pulley mechanism. The motor is capable of producing the equivalent of 26.5 N of grasping force (470 kPa) by the end effector jaws. Two strain gage force-sensing beams are mounted in the partial pulley to accurately measure applied force. Computer-control is provided using a proportional-derivative position controller to command cyclic (up to 3 Hz) or step loadings. The MEG can be hand-held, weighs about 0.7 kg, and can be inserted into the body through standard endoscopic ports. The MEG has been calibrated and validated on linear springs with known stiffness. $<$p$>$ The MEG has been used to test 7 different porcine abdominal organs in-vivo and through 24 hours postmortem. Elastic and relaxation properties have been recorded and analyzed. Constitutive force-deformation relations have been fit to the elastic data, and stress relaxation functions have been fit to the stress-time data recorded during relaxation tests. An understanding of how the tissue properties and model parameters are influenced by time postmortem and loading condition has been obtained.}, contents = {Th027} } @article{BRLTh028, author = {G.S. Lee}, title = {Low Power Haptic Devices: Ramifications on Perception and Device Design}, journal = {Ph.D. Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = jun, year = {2004}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th028.pdf}, abstract = {Haptics is a relatively new research field concerned with the study and design of devices that exchange information via the sense of touch. Embedding haptic displays into today's powerful handheld devices many enhance the manipulation of data contained within these ever shrinking devices. To that end, research has been undertaken to study this regime of operation. Experiments have measured that subjects can perceive haptic effects amplitudes less than six milliNewtons. Early results suggested avenues of investigation into hand position and haptic effect profiles. This dissertation discusses research which expands upon earlier results in order to yield intelligent design and implementation specifications for an embedded haptic cell-phone dialing interface.}, contents = {Th028} } @article{BRLTh029, author = {M. Lum}, title = {Kinematic Optimization of a 2-{DOF} Spherical Mechanism for a Minimally Invasive Surgical Robot}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = dec, year = {2004}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th029.pdf}, abstract = {In the late 1980s and early 1990s minimally invasive surgical (MIS) techniques revolutionized the way in which a significant number of surgical interventions were performed. Throughout the 1990s technological advances allowed for the development of a generation of robot manipulators for MIS procedures.  While revolutionary, these first generation manipulators were large and cumbersome. By analyzing and optimizing a spherical mechanism designed specifically for MIS this thesis lays the foundation upon which a next generation surgical manipulator will be designed. The kinematics of a 2-link serial and a 5-link parallel, 2 degree-of-freedom mechanisms is developed. Further, the workspace requirements are defined based on surgical measurements taken during actual MIS animal procedures. Using preliminary mechanical design practical joint limits are established. A scoring  criterion that takes into account average performance, a guaranteed minimum performance and proportionality to mechanism stiffness is defined using mechanism isotropy as the underlying metric. An overall optimization is performed for both serial and parallel configurations are performed. Adjustable passive aluminum mock-ups were designed and fabricated for experimental evaluation by surgeons of both serial and parallel combinations. From the experimental evaluation it was determined that the proper configuration should be two or more serial manipulators. The kinematic optimization shows that the best design of serial manipulator is 74 for Link1 and 60 for Link2. The results of this research are used in the design of a new surgical robotic system that will save critical space around the patient on the operating table, provide the surgeon with more dexterity than traditional MIS tools, and have the dynamic bandwidth to support for a force-feedback surgeon interface.}, contents = {Th029} } @article{BRLTh030, author = {G. Sankaranarayanan}, title = {Virtual Coupling Schemes for Position Coherency in Networked Haptic Virtual Environments}, journal = {Ph.D. Dissertation}, publisher = {University of Washington, Department of Electrical Engineering}, month = dec, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th030.pdf}, abstract = {In networked haptic virtual environments (NHVEs), multiple users remotely collaborate sharing the same virtual space. Maintaining position coherency between the copies of the virtual object in these environments is necessary to achieve consistency in collaboration, especially in the presence of time delays between users. To this end, three virtual coupling schemes are introduced in this thesis to maintain position coherency. Two of these utilize a peer-to-peer architecture and the third is a client-server. An experimental collaborative haptic system was built to objectively test the performance of the virtual coupling schemes. The schemes were first tested for constant time delays with virtual coupling parameters that resulted in stable operation. The experimental results demonstrate that one of the virtual coupling schemes has a comparable performance to the server-based method. Several globalscale haptic collaboration experiments were performed using the Internet to test the three three virtual coupling schemes under realistic network conditions and at three fixed packet transmission rates of 1000 Hz, 500 Hz and 100 Hz. Locally, the haptic update rate was maintained at 1000 Hz during all the experiments. The results show that the position error and the force rendered to the users increased with the reduction in the packet transmission rate. The results also demonstrated that a global-scale haptic collaboration is possible with a peer-to-peer architecture and maintaining position coherency at the same time.$<$p$>$ Two time-delay compensation techniques, wave variables and time-domain passivity controllers were used to stabilize the peer-to-peer scheme 1. The performance of these controllers was compared to a tuned PD controller in both stable and unstable regions of operation. The experimental results show that the tuned PD controller gave the best performance in terms of position error and wave variables in terms of force. In order to test the NHVE under repeatable network conditions, an emulator was implemented that can create realistic Internet-like characteristics in a laboratory setting. Experimental comparison of the performance of the virtual coupling schemes using the emulator and the Internet show that the emulator is best suited for testing NHVE under packet transmission rates below 1000 Hz.}, contents = {Th030} } @article{BRLTh031, author = {M. Lum}, title = {Quantitative Performance Assessment of Surgical Robot Systems: TeleRobotic {FLS}}, journal = {Ph.D. Dissertation}, publisher = {University of Washington, Department of Electrical Engineering}, month = aug, year = {2008}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th031.pdf}, abstract = {Robot assisted surgery is revolutionizing the way in which many surgical interventions are performed. Increased dexterity allows surgeons to perform procedures that were otherwise impossible. TeleSurgery will allow expert care to be distributed anywhere in the world that medical intervention is required. The development of the University of Washington, RAVEN Surgical Robot, was a collaborative effort between surgeons and engineers from multiple disciplines. Initial validation testing included, (1) operating through a digital-data-link on an unmanned aerial vehicle, (2) long-distance teleoperation collaborations with researchers in other countries, and (3) participation in a NASA training mission during which the RAVEN was placed in an undersea habitat off the Florida Keys and teleoperated from Seattle, WA. Based on the current standard in surgical skills evaluation, a method for objective assessment of surgical robotic systems was developed. The effect of time delay in telesurgery using the RAVEN and the effect of 3D vision using the ISI da Vinci robot were evaluated. The results of these studies will guide further development of the RAVEN and stimulate new ideas for telesurgery.}, contents = {Th031} } @article{BRLTh032, author = {S. De}, title = {Acute Indicators of Injury at the Grasper-Tissue Interface in Minimally Invasicve Surgery}, journal = {Ph.D. Dissertation}, publisher = {University of Washington, Department of Bioengineering}, month = jun, year = {2008}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th032.pdf}, abstract = {Minimally invasive surgical (MIS) techniques provide many patient benefits and are becoming preferred for a number of common procedures. However, poor tactile sensation from the tools used in these techniques, including surgical robots, can lead to inadvertent damage to tissues from excess stress application. In addition, lack of feedback from surgical simulators to surgical trainees regarding safe handling of tissues provides potentially inadequate training. Little is known about the types of stresses that can be applied safely to in vivo tissues during surgery and the local effects of surgical grasping. This work provides a systematic characterization of the grasper-tissue interface in MIS. It includes measurements of visual changes and stress profiles resulting from surgical grasping and introduces quantified relationships between tissue damage and stress at the cellular level. Using the porcine model, stresses typical to MIS were applied to in vivo organs using a motorized endoscopic grasper. Acute indicators of tissue damage including cellular death, vascular injury, and inflammation were measured using histological and image analysis techniques. Mixed-effects models of results indicate that stress magnitude, but not duration, can be used to predict tissue injury. Finite element analysis was used to identify approximate stress distributions experienced by the tissues between the grasper jaws. Correlations between damage measured from experimental studies and tissue models at the 5-10 millimeter scale further validate the ability to predict damage from stress magnitude. However, the correlation between computational and experimental results was less reliable at the submillimeter scale. Finally, an ‘atraumatic’ grasper design was evaluated using computational techniques. The results presented here provide a better understanding of the effects of grasping at surgically relevant parameters. They can be expanded upon and potentially used to design safer instruments and more accurate simulators. For example, it may be possible for researchers to create ‘smart’ surgical devices that guide surgeons to manipulate tissues with minimal resulting damage. Grasper designs that eliminate or reduce high tissue stresses may also aid in the development of better MIS tools. In addition, surgical simulators could be altered to reflect more realistic tissue responses and to evaluate trainees’ tissue handling skills.}, contents = {Th032} } @article{BRLTh033, author = {D. Friedman}, title = {Kinematic and Dynamic Analysis of a Surgical Robot Positioning Arm}, journal = {Master's Thesis}, publisher = {University of Washington, Department of Mechanical Engineering}, month = dec, year = {2008}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th033.pdf}, abstract = {Over time, operating rooms have become increasingly crowded. The introduction of surgical robots into the operating field has only exacerbated the problem. In an effort to reduce crowding, the BioRobotics Lab at the University of Washington (Seattle, WA) developed the RAVEN, a small form-factor surgical robot. To increase the RAVEN’s workspace and decrease setup time, the C-Arm was also developed to accurately support and position the RAVEN during surgery. The macro-micro manipulator system created by the C-Arm and the RAVEN occupies less space than a single manipulator with a similar workspace, can be used to automate setup procedures, and also increases patient safety. $<$p$>$ This thesis presents an analysis and computational implementation of the C-Arm’s for- ward kinematics and dynamics, along with a fast numerical solution for the inverse kine- matics. The inverse kinematics solution can be generalized to provide a solution for any six degree-of-freedom manipulator, assuming the forward kinematics are known and that it is possible to solve for the remaining joint angles if one joint angle’s value is known. With a fast numerical method and the current levels of computing power, designing a manipulator with closed-form inverse kinematics is no longer necessary. When designing the C-Arm, we therefore chose to weigh other factors, such as actuator size and patient safety, more heavily than the ability to find a closed-form inverse kinematics solution. The equations presented here will be used when controlling the C-Arm either alone or with the RAVEN.}, contents = {Th033} } @article{BRLTh034, author = {P. Roan}, title = {An Instrumented Surgical Tool for Local Ischemia Detection}, journal = {Ph.D. Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = mar, year = {2011}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th034.pdf}, abstract = {Minimally invasive surgical procedures have improved the standard of patient care by reducing recovery time, chance of infection, and scarring. A recent review estimates that leaks occur in 3\% to 6\% of bowel anastomoses, resulting in “increased morbidity and mortality and adversely [affecting] length of stay, cost, and cancer recurrence”[53]. Many of these leaks are caused by ischemic tissue. This dissertation covers the development of a surgical tool for reliable ischemia detection during routine manipulation of the tissue. The design of the tool and choice of the sensors leverages existing work in physiological measurements and surgical tool design. Detecting a change in temperature can indicate ischemic tissue. The optical absorption spectrum of a tissue can be used to detect tissue oxygen concentration and tissue ischemia. Electrical impedance of ischemic tissue changes over time due to cell swelling, closing intercellular gap junctions, and the accumulation of metabolic products [38]. Ad- ditionally, collecting simultaneous data from multiple sensors allows the computer to make a stronger decision than on just one sensor at a time. The tool includes sensors for measuring the temperature, local optical absorption spectrum, and electrical impedance of the grasped tissue, while controlling the grasp force and jaw position, thereby controlling the tool-tissue interface. Data was collected from 9 animals and analyzed using artificial neural networks (ANN) and support vector machines (SVM). Classification results for the entire data set reached 67\% for the best SVM implementation and 73\% for the ANN. Classification results on each animal individually averaged 85\% for the SVM and 89\% for the ANN.}, contents = {Th034} } @article{BRLTh035, author = {D.C.W. Friedman}, title = {Scaling Laws and Size Thresholds for Minimally Invasive Surgical Instruments}, journal = {Ph.D. Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = jun, year = {2011}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Th035.pdf}, abstract = {Minimally invasive surgery introduced significant changes to the field of surgery. New procedures became possible, and existing procedures were performed in new ways. With the increasing popularity of robotic surgery, the field is changing once again. One significant impact of robotic surgery is the ability to scale motions. The surgeon can move his hands over a distance of ten centimeters and see the tool tips move only two centimeters. As time passes, surgeons will expect the scaling to continue, with tool tips moving only a few millimeters when they move their hands over a distance of ten centimeters, and with the tool tips themselves shrinking at the same rate. As robotic surgery progresses, it will be important to know how small surgical tools can be made and still be functional. The focus of my dissertation is to identify size thresholds for key components of minimally invasive surgical instruments. $<$p$>$ For my dissertation, I focused on rigid graspers and needle drivers with articulated wrists. I developed a reference geometry similar to currently available instruments, and used it to identify a set of pertinent physical properties that should be considered for minimally invasive surgical instruments. I also conducted a brief survey of published material on tissue properties and developed a model of real world constraints that need to be met, including the maximum safe force that can be applied to tissue and the force needed to grasp a suture needle. After collecting this information, I defined a series of design thresholds based on the physical principles I identified and my real world constraints model, and in the context of the reference instrument design I identified. These design thresholds indicate the useful range of instrument diameters for which the instrument can satisfy all of the real world constraints. $<$p$>$ My dissertation also includes a comprehensive survey of reported da Vinci instrument failures compiled from the FDA’s MAUDE database. Surgeons and institutions can voluntarily (and anonymously) report adverse events (such as instrument failures), and the product manufacturer can provide a response. This survey identifies common types of failures, but does not provide information about relative instrument failure rates.}, contents = {Th035} } @misc{XXX??c, author = {{XXX}}, title = {{YYY}}, institution = {XXX}, year = {ZZZ} } @article{BRLM016, author = {Blake Hannaford and Sugandhan Venkatachalam}, title = {Characterization of Test Balls for Psychophysical Experiments}, journal = {University of Washington Electrical Engineering Department Technical Report}, volume = {2009-0006}, month = {June 5}, year = {2009}, annote = {https://www.ee.washington.edu/techsite/papers/refer/UWEETR-2009-0006.html}, abstract = {This report documents shape and curvature measurements of seven test spheres and three control spheres used in psychophysical experiements in the Biorobotics Lab.}, contents = {M016} } @article{BRLM015, author = {Blake Hannaford and Jesse Dosher}, title = {Polishing and Measuring Distorted Spheres for Psychophysical Experimentation}, journal = {University of Washington Electrical Engineering Department Technical Report}, volume = {2009-0004}, month = {April 24}, year = {2009}, annote = {https://www.ee.washington.edu/techsite/papers/refer/UWEETR-2009-0004.html}, abstract = {How well can people detect shape with their fingers? How accurately can they discriminate between two small shapes? To study this problem, the Biorobotics Lab will test people's ability to detect which of two spherical ball bearings is ``perfect'' and which is out-of-round. An earlier report described grinding procedures for making precise distortions of spheres. The spheres then must be polished to remove surface texture cues that might confuse the experiment. This report describes polishing methods used to achieve uniform texture on the spheres, and also a system for precisely measuring the profile of a circular cross section of the distorted and polished spheres.}, contents = {M015} } @article{BRLM014, author = {Blake Hannaford and Diana Friedman and Hawkeye King and Mitch Lum and Jacob Rosen and Ganesh Sankaranarayanan}, title = {Evaluation of {RAVEN} Surgical Telerobot during the {NASA} Extreme Environment Mission Operations ({NEEMO}) 12 Mission}, journal = {University of Washington Electrical Engineering Department Technical Report}, volume = {2009-0002}, month = {6-Feb-}, year = {2009}, annote = {https://www.ee.washington.edu/techsite/papers/refer/UWEETR-2009-0002.html}, abstract = {The University of Washington’s BioRobotics Laboratory, under the direction of Dr Blake Hannaford, supported the University of Cincinnati’s telesurgery effort during the NEEMO 12 mission conducted May 7-18, 2007. The UW RAVEN telerobotic system was deployed to the Aquarius Habitat to conduct a variety of research tasks. The goals of this mission were to advance and demonstrate technologies related to remote healthcare for astronauts on extended space missions. In particular, the capability of surgical intervention by remotely operated surgical robotics. Two surgical robots were deployed into the Aquarius habitat, the UW RAVENand the SRI, International M7 robot. Control of the robots was provided over an Internet link from UW (Seattle, WA) and SRI (Palo Alto, CA), respectively. The last 10 mile connection to the remote site was provided by a microwave link from shore to buoy and a 20m cable down to the habitat. Organization for the remote surgery component of the NEEEMO-12 mission is included expertise from Dr. Hannaford, Dr. Jacob Rosen, Mr. Mitch Lum, and Ms Diane Friedman. RAVEN was succesfully operated in the NEEEMO habitat and teleoperated from Seattle.}, contents = {M014} } @article{BRLM013, author = {Blake Hannaford}, title = {Making Distorted Spheres for Psychophysical Experimentation}, journal = {University of Washington Electrical Engineering Department Technical Report}, volume = {2009-0001}, month = {Rev April-}, year = {2009}, annote = {https://www.ee.washington.edu/techsite/papers/refer/UWEETR-2009-0001.html}, abstract = {How well can people detect shape with their fingers? How accurately can they discriminate between two small shapes? To study this problem, the Biorobotics Lab will test people's ability to detect which of two spherical ball bearings is ``perfect'' and which is out-of-round. To create test objects for this work, we need a method to produce out-of-round spheres. Starting with factory made ball bearings, this report describes procedures we have developed to grind, sand, and polish the balls into a deformed shape with deformations as low as 0.002 inches. Care is taken to make sure surface texture is removed as a clue.}, contents = {M013} } @article{BRLM012, author = {C. Doarn and K. Hufford and T. Low and J. Rosen and B. Hannaford}, title = {Roundtable Discussion: Telesurgery and Robotics}, journal = {Telemedicine and e-Health}, volume = {13}, number = {4}, publisher = {Mary Ann Liebert, Inc.}, year = {2007}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/RepM012.pdf}, abstract = {Charles R. Doarn: Thanks, everyone, for participating in our discussion today. I’m Chuck Doarn at the University of Cincinnati. We do a fair amount of work with DoD and NASA in the area of telesurgery. One of my colleagues, Dr. Tim Broderick, who is an avid telesurgeon, couldn’t be with us today. He sends his regards and has a lot of discussion points for our conference today.}, contents = {M012} } @inproceedings{BRLM011, author = {G. Borriello and T. Choudhury and B. Hannaford and N. Kern and J. Lester}, title = {Choosing the Right Modalities and Features for Activity Recognition}, booktitle = {Neural Information Processing Systems 2004 Workshop on Multimodal Signal Processing}, address = {Whistler, British Columbia}, year = {2004}, contents = {M011} } @inproceedings{BRLM010, author = {G. Klute and J. Czerniecki and B. Hannaford}, title = {{ARTIFICIAL} {MUSCLES}: {ACTUATORS} {FOR} {LOWER} {LIMB} {PROSTHESES}}, booktitle = {Proceedings of the 2nd Annual Meeting of the VA Rehabilitation Research and Development Service}, pages = {107}, address = {Washington DC}, month = {February 20-22}, year = {2000}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/RepM010/index.html}, abstract = {Prosthetic clinical experience indicates many veterans suffer from lack of endurance, non-symmetrical gait, and high levels of effort while simply walking at their self-selected pace. The integration of an artificial musculo-tendon actuator into a below-knee prosthesis has the potential to greatly improve amputee gait by providing the missing propulsive force of the ankle musculature.}, contents = {M010} } @inproceedings{BRLM009, author = {D. Wilson and B. Hannaford}, title = {Robust Electronic Design: What's That?}, booktitle = {Proc. Frontiers in Engineering Education}, address = {Reno, NV}, month = {Oct 10-13}, year = {2001}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/RepM009.pdf}, abstract = {This paper presents an overview of a two course sequence in robust consumer electronic design recently intro-duced in the senior curriculum in electrical engineering at the University of Washington. The focus of the course sequence is on the design process itself, from the creative generation of the consumer product idea to the redesign of that product to meet the robustness threshold required for commercial marketability. Student responses to the course sequence express conflict among their exposure to traditional engineering topics, their expectations as developed through the sophomore and junior EE curriculum at UW, their expec-tations of the industry experience, and their perceptions of the new ABET criteria and educational goals. Students dem-onstrate significant resistance to the teaching of soft skills related to design process and principle, yet respond very well to the opportunity to engage in open-ended design. Experi-ence from the first offering of this integrated sequence in robust design for consumer electronics has clearly shown the need to bridge the gap between what engineering students think they need to know and what industry would like them to know in order to enable the effective use of projects that are not pre-cooked by instructors but rather are student-driven and motivated. We present the framework and description of the course sequence here, preliminary assess-ment results from the first sequential offering of the courses, and a directed path toward improvement in electrical engi-neering robust design education for consumer electronics in future offerings of the sequence.}, contents = {M009} } @inproceedings{BRLM008, author = {J.D. Brown and J. Rosen and J. Longnion and M. Sinanan and B. Hannaford}, title = {Design and Performance of a Surgical Tool Tracking System for Minimally Invasive Surgery}, booktitle = {Abstract: Proceedings of the ASME International Mechanical Engineering Congress and Exposition: Advances in Bioengineering, BED}, volume = {51}, pages = {169-170}, publisher = {ASME}, address = {New York}, month = {Nov. 11-16}, year = {2001}, abstract = {The technique of minimally invasive surgery (MIS) introduces new interfaces as compared to more traditional open surgical techniques. These interfaces impose motion constraints and forces on the tool(s) and hand(s). These interfaces are not well characterized, yet surgical simulators and surgical robots are being developed without this vital information. Much work has been done by our group with regard to measuring and analyzing the forces and torques being applied by the surgeons during two common laparoscopic procedures in order to objectively evaluate skill level. However, it is assumed that quantifying tool position would help to further discriminate skill level by allowing analysis of power and energy production by the surgeon: expert surgeons are hypothesized to exert less effort, as measured by mechanical work, than a non-expert during the course of an operation. A system for measuring these motions, as well as the forces and torques applied during surgery is described and evaluated.}, contents = {M008} } @article{BRLM007, author = {J. Rosen and M. Solazzo and B. Hannaford and M. Sinanan}, title = {Task Decomposition of Minimally Invasive Surgery for Objective Evaluation of Laparoscopic Surgical Skills Using Hidden Markov Models}, journal = {Abstract: BMES 2000, Biomedical Engineering Society, Annual Meeting, Annals of Bioengineering}, volume = {28, Supplement 1}, address = {Seattle, WA}, month = oct, year = {2000}, abstract = {Laparoscopic skill evaluation of surgical residents is usually a subjective process, carried out by senior surgeons using fuzzy criteria. The aim of this study was to develop and assess an objective laparoscopic surgical skill scale using Hidden Markov Models (HMM) based on haptic information, tool/tissue interactions and visual task decomposition. Eight subjects (six residents: R1, R3, R5 at different training levels, and two experts ES)performed laparoscopic cholecystectomy on pigs using an instrumented grasper equipped with force-torque (F/T) sensors at the hand/tool inferace and synchronized video of the operative maneuvers. Fourteen types of tool/tissue interactions, each associated with unique F/T signatures, were defined from frame-by-frame video analysis. The statistical distances between HMMs representing expert surgeons and residents were significantly different. Major differences were: (i) F/T magnitudes, (ii) tool/tissue interactions used and transitions between them, (iii) time intervals in each tool/tissue interaction and overall completion time. The greatest difference in performance was between R1 (junior trainee) and R3 (mid-level trainee). Smaller changes were seen as expertise increased beyond the R3 level. This objective learning curvey suggests that the laparoscopic surgical residents acquire a major portion of their skill between the first and the third eyars of their 5 years of training. (formerly M143)}, contents = {M007} } @article{BRLM006, author = {J. Brown and J. Rosen and B. Hannaford and M. Sinanan}, title = {A Passive Mechanical Pantograph System for Measuring Tool Position During Minimally Invasive Surgery (Poster)}, journal = {BMES 2000, Biomedical Engineering Society, Annual Meeting. Annals of Bioengineering}, volume = {28, Supplement 1}, address = {Seattle, WA}, month = oct, year = {2000}, abstract = {Relatively little is known about the forces and displacements applied to tissues in minimally invasive surgical procedures. In previous research, we have measured forces and torques surgeons apply during laparoscopic cholecystectomy and Nissen fundoplication. To better understand the biomechanics of the procedure, we want to measure the movements of the surgical tool using a passive mechanical "pantograph" system, utilizing lightweight aluminum and composite materials. With this data, surgeons' work and energy expenditures can be calculated. A mock-up of the system was tested in the operating room and found suitable for surgeons' use. Rotary potentiometers measure the position and orientation of the tool tip with 0.028mm of repeatability, as well as the amount of opening of the tool's jaws. The system can be constrained to allow movement in a single plane. Using the previously developed force-sensing tool, we will gather reaction force data at the abdominal wall interface and record the movements of the surgeons' instruments during a surgical procedure. This information will allow development of models of the abdominal wall for more accurate surgical simulators. (formerly M142)}, contents = {M006} } @article{BRLM005, author = {P. Buttolo and J. Hewitt and R. Oboe and B. Hannaford}, title = {Force Feedback in Virtual and Shared Environments}, journal = {Poster: IEEE Intl. conf. on System, Man and Cybernetics}, address = {Vancouver BC}, month = oct, year = {1995}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep100.pdf}, abstract = {We will present a demonstration allowing people to touch virtual objects and perform elementary manipulations, with visual and haptic feedback. The virtual environment consists of collision detection and dynamics software modules, a simple graphics representation, plus the kinematics and dynamics interface necessary to drive the force display. We will also present a force-feedback virtual squash, with two or more players located in Seattle and Padova (Italy). The game is an example of how to implement force feedback in a shared environment. The reproduction of a faithful and stable force signal to the operator requires the computation of forces with low latency and high. [POSTER]. (formerly 100)}, contents = {M005} } @inproceedings{BRLM004, author = {B. Hannaford}, title = {Non-linear Phasic Dynamics of Muscle Activation and Force Generation}, booktitle = {Abstract: Proceedings ISEK 90}, pages = {345-348}, address = {Baltimore MD}, month = aug, year = {1990}, abstract = {A model has been developed of the dynamics of the excitation of the motoneuron, the transduction of action potentials to muscle activation and the generation of muscle force. The PEXA model has been calibrated and tested against in vivo experimental data and reproduces the non-linear adaptation behavior of the moto-neuron and the non-linear enhancement of muscle tension at short inter-stimulus intervals. The model will be useful in detailed dynamical modeling of high speed voluntary movements. (formerly 060)}, contents = {M004} } @article{BRLM003, author = {B. Hannaford and et al.}, title = {Force-Feedback Cursor Control}, journal = {NASA Tech Briefs}, volume = {13}, number = {11,item \#21}, month = nov, year = {1989}, contents = {M003} } @book{BRLM002, author = {W.S. Kim and B. Hannaford}, title = {Active Compliance for Shared Control}, publisher = {Jet Propulsion Laboratory Engineering Memorandum 347-89-259}, month = jan, year = {1989}, abstract = {formerly (047)}, contents = {M002} } @article{BRLM001, author = {B. Hannaford}, title = {Comments on the Article "Process Control Simulation using Spreadsheets"}, journal = {Letter to TAPPI Journal}, year = {1988}, abstract = {formerly (025)}, contents = {M001} } @article{XX??, author = {{XX}}, title = {{XX}}, institution = {XX}, journal = {YY} } @article{BRL001, author = {KR Walley and M Grover and GL Raff and JW Benge and B Hannaford and SA Glantz}, title = {Left ventricular Dynamic Geometry in the Intact and Open Chest Dog}, journal = {Circulation Research}, volume = {50}, pages = {573-589}, year = {1982}, contents = {001} } @inproceedings{BRL002, author = {B. Hannaford and R. Maduell and M.H. Nam and V. Lakshminarayanan and L. Stark}, title = {Effects of Loads on Time-Optimal Head Movements: {EMG}, Oblique, and Main Sequence Relationships}, booktitle = {Proceedings of the 19th Annual Conference on Manual Control}, address = {Cambridge MA}, year = {1983}, contents = {002} } @article{BRL003, author = {B. Hannaford and M.H. Nam and V. Lakshminarayanan and L. Stark}, title = {Electromyographic Evidence of Neurological Controller Signal with Viscous Load}, journal = {Journal of Motor Behavior}, volume = {16}, pages = {255-274}, year = {1984}, contents = {003} } @inproceedings{BRL004, author = {W.S. Kim and S.H. Lee and B. Hannaford and L. Stark}, title = {Inverse Modeling to Obtain Head Movement Controller Signal}, booktitle = {Proceedings of the 20th Annual Conference on Manual Control}, address = {Sunnyvale, CA.}, month = jun, year = {1984}, abstract = {Inversion of 6th order Non-linear model for 3 magnitudes of time optimal and 2 interesting slow movements. Discussion of interesting issues in numberical analysis and filtering.}, contents = {004} } @inproceedings{BRL005, author = {B. Hannaford and L. Stark}, title = {Control Strategies for Neurologically Ballistic Movements}, booktitle = {Proceedings of the 37th ACEMB}, address = {Los Angeles, CA}, month = sep, year = {1984}, abstract = {First published PABC result.}, note = {Abstract}, contents = {005} } @article{BRL006, author = {B. Hannaford and L. Stark}, title = {Roles of the elements of the Tri-Phasic Control Signal}, journal = {Experimental Neurology}, volume = {90}, pages = {619-634}, year = {1985}, abstract = {PABC Paper. (see also Abstract for ACEMB LA, 9/84)}, contents = {006} } @article{BRL007, author = {B. Hannaford and S.A. Glantz}, title = {Adaptive linear predictor tracks implanted radiopaque markers}, journal = {IEEE Trans. Biomedical Engineering}, volume = {BME-32}, pages = {117-125}, year = {1985}, abstract = {Radiopaque markers implanted in the heart's wall permit one to observe absolute motion of the heart in closed-chest animals and humans using X-rays. The resulting data, however, are very tedious to analyze because human operators must digitize the observed marker motion from cineradiographic films (or stored video images). This paper describes an algorithm that tracks the trajectories of markers implanted in the endocardium. The algorithm uses a least-mean-squares adaptive linear predictor. By solving the marker tracking problem, one moves closer to a fully automated endocardial marker data acquisition system. The algorithm is also used to detect errors in data acquired using manual digitizing procedures. Tests run with data from nine dogs showed that the algorithm could successfully track and identify 95-100 percent of the markers in 40 out of the 60 film segments and 90-100 percent of the markers in 52 out of 60. The root-mean- square distance between the identified marker trajectories and the manually determined trajectories, a measure of accuracy, was about one-half the marker size when averaged over all of the film segments tested.}, contents = {007} } @article{BRL008, author = {B. Hannaford and C.C. Krischer and L. Stark}, title = {A Device for Zero Eye Movement Reading}, journal = {IEEE Trans. Biomedical Engineering}, volume = {BME-32}, pages = {86-89}, year = {1985}, abstract = {A portable personal computer has been programmed as a flexible and economical text display device capable of delivering single and multiple words or symbols flashed in the center of the screen with a wide range of repetition times and duty cycles (fraction of stimulus on/off time). All aspects of a computer- controlled experiment are controlled by a command file which can be created by workers with basic word processing skills and no knowledge of computer programming. Digital output is provided for recording stimulus timing on a chart recorder or computer for comparison to eye movements or other externally recorded variables. The system is ideal for zero-eye-movement reading experiments in which sentences are flashed a word or group of words at a time in the center of a CRT screen. If the subject is then asked to repeat the sentence aloud, the percentage of words correctly recalled is a measure of "reading comprehension." Results with nine subjects match previous data [1] obtained cinematographically.}, contents = {008} } @article{BRL009, author = {B. Hannaford and G. Cheron and L. Stark}, title = {The Effects of Applied Vibration on the Tri-Phasic {EMG} Pattern in Neurologically Ballistic Head Movements}, journal = {Experimental Neurology}, volume = {88}, pages = {447-460}, year = {1985}, abstract = {Vibration of agonist or antagonist muscle tendon produced changes in the triphasic electromyographic pattern of neck muscles; EMG signals were rectified, averaged, and also integrated by planimetry. The triphasic EMG envelopes obtained during fast horizontal head rotation showed unmodified early agonist pulse, the action pulse (PA), under all conditions; increased antagonist pulse, the braking pulse (PB), only with antagonist muscle vibration; and increase of late agonist pulse, the clamping pulse (PC), only with agonist muscle vibration. Vibration experiments can be considered as a model for studying interactions between central and peripheral effects on control of normal movements.}, contents = {009} } @book{BRL010, author = {B. Hannaford}, title = {Control of Fast Movement: Human Head Rotation, Ph.{D}. Thesis}, publisher = {Department of Electrical Engineering and Computer Science}, address = {University of California, Berkeley}, year = {1985}, contents = {010} } @article{BRL011, author = {B. Hannaford and W.S. Kim and S.H. Lee and L. Stark}, title = {Neurological Control of Head Movements: Inverse Modeling and Electromyographic Evidence}, journal = {Math. BioScience}, volume = {78}, pages = {159-178}, year = {1986}, abstract = {Experimentally obtained dynamics of time-optimal, horizontal head rotations have previously been simulated by a sixth order, nonlinear model drive by rectangular control signals. EMG recordings have aspects which differ in detail from the theoretical rectangular pulsed control signal. We have obtained control signals for time-optimal (with triphasic EMG activity) as well as suboptimal horizontal head rotations by means of a newly developed inverse modeling procedure. With experimentally measured dynamical data serving as the input, this procedure inverts the model to produce the neurological control signals driving muscle and plant. The relationships between these controller signals and EMG records should contribute to our understanding of the neurological control of movements.}, contents = {011} } @article{BRL012, author = {N. Akamatsu and B. Hannaford and L. Stark}, title = {An Intrinsic Mechanism for the oscillatory contraction of muscle}, journal = {Biological Cybernetics}, volume = {53}, pages = {219-227}, year = {1986}, abstract = {A new model based on the theory of dynamical systems is proposed for the intrinsic random or pseudo-random mechanism underlying certain types of muscular tremor. The active length-tension curve of the individual sarcomere, in conjunction with the passive length-tension relation is a map from length to tension with an observed time delay between length change and resulting tension change. The passive length tension relation is assumed to instantaneously relate this tension change back to a change in length. The stability properties of this iterated interval map are investigated by means of computer simulation and computation of the Lyapunov exponent and the bifurcation tree. The resulting analysis is related to experimental tremor data in the literature in terms of period doubling, bifurcation points, and "chaotic" behavior. The model appears to have its most fruitful application in understanding the insect type and isometric mammalian types of tremor.}, contents = {012} } @inproceedings{BRL013, author = {B. Hannaford}, title = {The Electronic Spreadsheet: {A} Workstation Front End for Parallel Processors}, booktitle = {Proceedings IEEE Computer Conference}, pages = {316-321}, address = {San Francisco, CA}, month = {March 3-6}, year = {1986}, contents = {013} } @incollection{BRL014, author = {L. Stark and W.H. Zangemeister and B. Hannaford and K. Kunze}, editor = {K. Kunze and W.H. Zangemeister and A. Arlt}, title = {Use of Models of Brainstem Reflexes for Clinical Research}, booktitle = {Clinical Problems of Brainstem Disorders}, pages = {172-184}, publisher = {Georg Thieme Verlag}, address = {Stuttgart}, year = {1986}, contents = {014} } @article{BRL015, author = {B. Hannaford and S. Lehman}, title = {Short Time Fourier Analysis of the Electromyogram: Fast Movements and Constant Contraction}, journal = {IEEE Transactions on Biomedical Engineering}, volume = {BME-33}, pages = {1173-1181}, month = dec, year = {1986}, abstract = {We applied short-time Fourier analysis to surface electromyograms (EMG) recorded during rapid movements, and during isometric contractions at constant forces. We selected a portion of the data to be transformed by multiplying the signal by a Hamming window, then computed the discrete Fourier transform. Shifting the window along the data record, we computed a new spectrum each 10 ms. We displayed the transformed data in spectrograms or "voiceprints." This short-time technique allowed us to see time-dependencies in the EMG that are normally averaged in the Fourier analysis of these signals. Spectra of EMG's during isometric contractions at constant force vary in the short (10-20 ms) term. Moments of the spectral distribution show this variability. Short-time spectra from EMG's recorded during rapid movements were much less variable. The windowing technique picked out the typical "three-burst pattern" in EMG's from both wrist and head movements. Spectra during the bursts were more consistent than those during isometric contractions. Furthermore, there was a consistent shift in spectral statistics in the course of the three bursts. Both the center frequency and the variance of the spectral energy distribution grew from from the first burst to the second burst in the same muscle. We discuss this pattern with respect to the origin of the EMG bursts in rapid movement. We also extend the analogy between electromyograms and speech signals to argue for future applicability of short-time spectral analysis of EMG.}, contents = {015} } @article{BRL016, author = {D.S. Holder and A. Scott and B. Hannaford and L. Stark}, title = {High Resolution Electromyogram of the Human Eyeblink}, journal = {Electromyogr. and Clinical Neurophys.}, volume = {27}, pages = {481-488}, year = {1987}, abstract = {The relationship between the electromyogram of the human eyelid muscles and eyelid movement was investigated, using needle and surface EMG recordings and limbus reflectance spectacles to obtain a simultaneous highly resolved record of eye aperture. It was found that the EMG pattern consisted of a single pulse envelope for each of the orbicularis oculi and levator palpbrae superioris, which lasted for an average of 129 and 195 ms respectively. Co-inhibition was present just prior to orbicularis activity, and co-contraction was present during lid closure. Each EMG pulse preceeded maximal velocity of eye aperture change by about 80 ms. Changes in duration of the blink correlated best with alterations in the duration of eye closing and opening phases, with no significant change in EMG. This suggested a change in the pattern of motor unit recruitment. A pulse corresponding to levator activity was observed in the averaged surface EMG trace, though it may have been artifactual. It was concluded that the eyeblink provides a useful simple system for investigation of the relation of the EMG to dynamic muscle movement.}, contents = {016} } @article{BRL017, author = {D.S. Holder and W.S. Kim and B. Hannaford and L. Stark}, title = {Simulation of The Human Eyeblink using the {EMG} of Eyelid Musculature as Input}, journal = {Muscle and Nerve}, volume = {In Press}, year = {1985}, contents = {017} } @article{BRL018, author = {L. Stark and B. Hannaford and C.F. Ramos}, title = {Interaction of Descending Control and Stretch Reflex in Fast Voluntary Movements in Man}, journal = {Society for Neuroscience Abstract}, month = nov, year = {1986}, contents = {018} } @article{BRL020, author = {B.J. Martin and B. Hannaford and L. Stark}, title = {Effets Des Vibrations Musculaires Previsibles ou Imprevisibles sur les Mouvements Balistiques de la Tete}, journal = {Journal de Biomechanique}, volume = {10}, pages = {73-74}, year = {1986}, abstract = {Les mouvements de la tete effectues en temps optimum, ou "neurologiquement balistiques", correspondent a une activation triphasique des muscles du cou. Celle-ci se decompose en une impulsion initiale dans les muscles agonistes (PA:impulsion d'activation), suivie d'une impulsion dans les antagonistes (PB:impulsion de freinage) et d'une impulsion tardive des agonistes (PC: impulsion de blocage). L'application d'une vibration aux muscles agonistes ou antagonistes du mouvement est susceptible de modifier le pattern des electromyogrammes (1). Des etudes recentes ont montre la sensibilite, aux vibrations, des fuseaux neuromusculaires (2, 3) et ont confirme leur implication dans le controle du movement (4,5). Le but de cette etude etait d'une part, de comparer les effets moteurs et comportementaux d'une vibration musculaire previsible ou imprevisible, sur des movements neurologiquement balistiques de la tete, et d'autre part d'etudier l'interaction entre les commands centrales et les regulations peripheriques du mouvement.}, contents = {020} } @inproceedings{BRL021, author = {P. Fiorini and B. Hannaford and B. Jau and E. Kan and A. Bejczy}, title = {Hand Trigger System for Bi-Lateral Gripping Control in Teleoperation}, booktitle = {Proceedings of the IEEE International Conference on Robotics and Automation}, volume = {1}, pages = {586-592}, month = apr, year = {1987}, contents = {021} } @article{BRL022, author = {W.S. Kim and S.R. Ellis and M. E. Tyler and B. Hannaford and L. Stark}, title = {Quantitative Evaluation of Perspective and Stereoscopic Displays in Three Axis Manual Tracking Tasks}, journal = {IEEE Trans. Systems Man \& Cybernetics}, volume = {SMC-17}, number = {1}, pages = {61-72}, year = {1987}, abstract = {Optimal presentation of three-dimensional information on a two-dimensional display screen requires careful design of the projection to the display surface. Monoscopic perspective projection alone is usually not sufficient to represent three-dimensional spatial information. It can, however, be improved by the adjustment of perspective parameters and by geometric visual enhancements such as reference lines and a background grid. Stereoscopic display is another method of providing three-dimensional information to the human operator. Two experiments are performed with three-axis manual tracking tasks. The first experiment investigates the effects of perspective parameters on tracking performance. The second experiment investigates the effects of visual enhancements for both monoscopic and stereoscopic displays. Results indicate that, though stereoscopic displays do generally permit superior tracking performance, monoscopic displays can allow equivalent performance when they are defined with optimal perspective parameters and provided with adequate visual enhancements.}, contents = {022} } @article{BRL023, author = {L. Stark and W.S. Kim and F. Tendick and B. Hannaford and S. Ellis and et al.}, title = {Telerobotics; Display, Control, and Communication Problems}, journal = {IEEE Journal of Robotics and Automation}, volume = {RA-3}, pages = {67-74}, year = {1987}, abstract = {An experimental telerobotics (TR) simulation is described suitable for studying human operator (HO) performance. Simple manipulator pick-and-place and tracking tasks allowed quantitative comparison of a number of calligraphic display viewing conditions. An enhanced perspective display was effective with a reference line from target to base, with or without a complex three- dimensional grid framing the view. This was true especially if geometrical display parameters such as as azimuth (AZ) and elevation (EL) were arranged to be near optimal. Quantitative comparisons were made possible utilizing control performance measures such as root mean square error (rmse). There was a distinct preference for controlling the manipulator in end-effector Cartesian space for our primitive pick-and-place task, rather than controlling joint angles and then, via direct kinematics, the end-effector position. An introduced communication delay was found to produce decrease in performance. In considerable part, this difficulty could be compensated for by preview control information. That neurological control of normal human movement contains a sampled data period of 0.2 s may relate to this robustness of HO control to delay.}, contents = {023} } @inproceedings{BRL024, author = {B. Hannaford}, title = {Task Level Testing of the {JPL}-{OMV} Smart End Effector}, booktitle = {Proceedings of the JPL - NASA Workshop on Space Telerobotics}, volume = {2}, pages = {371-380}, publisher = {JPL Publication 87-13}, address = {Pasadena, CA}, month = {July 1}, year = {1987}, contents = {024} } @incollection{BRL026, author = {L. Stark and W.H. Zangemeister and B. Hannaford}, editor = {B. Peterson and F. Richmond}, title = {Head Movement Models, Optimal Control Theory and Clinical Application}, booktitle = {Control of Head Movement}, pages = {245-260}, publisher = {Oxford}, year = {1988}, contents = {026} } @article{BRL027, author = {B. Hannaford and L. Stark}, title = {Late Agonist Burst ({PC}) Required for Optimal Head Movement: a Simulation Study}, journal = {Biological Cybernetics}, volume = {57}, pages = {321-330}, year = {1987}, abstract = {Fast as possible (time optimal) single joint movements throughout the body are characterized by the triphasic (3 pulse) pattern of activation in the agonist and antagonist muscles. Simulation studies using a sixth order, non-linear model were undertaken to determine the relationship between time optimal movement and three pulse control. Exhaustive exploration of the multidimensional space formed by descriptive parameters of the control signal yielded control signals which drove the model to produce optimal movements. The result of these one to two week computer simulation runs was that if the limb is required to stay close to the target immediately after the end of the control signal, the fastest movements are produced by a three pulse control signal.}, contents = {027} } @inproceedings{BRL028, author = {B. Hannaford and L. Stark}, title = {Local Linearity of {EMG} to activation Mapping: Simulation Compared with Experiments}, booktitle = {Proceedings 1987 EMBS}, pages = {272-3}, address = {Boston}, month = nov, year = {1987}, abstract = {Based on Chapt. 6 of thesis. 2 pages, 2 figures.}, contents = {028} } @inproceedings{BRL029, author = {B. Hannaford and M. Salganicoff and A.K. Bejczy}, editor = {S.R. Ellis and M. Kaiser}, title = {Displays for Telemanipulation}, booktitle = {Proceedings Spatial Displays and Spatial Instruments Conference}, publisher = {NASA Conference Publication 10032}, month = {Aug. 31-Sep 3}, year = {1987}, contents = {029} } @inproceedings{BRL030, author = {B. Hannaford and R. Anderson}, title = {Experimental and Simulation Studies of Hard Contact in Force Reflecting Teleoperation}, booktitle = {Proc. IEEE Conference on Robotics and Automation}, pages = {584-589}, month = apr, year = {1988}, contents = {030} } @article{BRL031, author = {B. Hannaford}, title = {A Design Framework for Teleoperators with Kinesthetic Feedback}, journal = {IEEE Transactions on Robotics and Automation}, volume = {5}, number = {4}, pages = {426-434}, year = {1989}, abstract = {A teleoperator is a pair of robot manipulators connected in such a way as to allow an operator handling one manipulator (the master) to operate on a remote environment (via the slave). Feedback from slave to master increases the realism with which the operator interacts with the environment. Two-port models have been extensively used for the analysis of circuits in which bidirectional energy flows are present at two distinct pairs of terminals. This paper applies the hybrid two-port model to teleoperators with force and velocity sensing at the master and slave. The interfaces between human operator and master, and between environment and slave, are ports through which the teleoperator is designed to exchange energy between the operator and environment. By computing or measuring input-output properties of this two-port network, the hybrid two-port model of an actual or simulated teleoperator system can be obtained. It is shown that the hybrid model (as opposed to other two-port forms) leads to an intuitive representation of ideal teleoperator performance and applies to several teleoperator architectures. Thus measured values of the "h" matrix or values computed from simulation can be used to compare performance with the ideal. The frequency-dependent "h" matrix is computed from a detailed SPICE model of an actual system, and the method is applied to a proposed new architecture.}, contents = {031} } @inproceedings{BRL032, author = {B. Hannaford and P. Fiorini}, title = {A Detailed Model of Bilateral (Position/Force) Teleoperation}, booktitle = {Proceedings International Conference on Systems, Man, and Cybernetics}, pages = {117-121}, address = {Beijing}, month = aug, year = {1988}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep032.pdf}, contents = {032} } @inproceedings{BRL033, author = {B. Hannaford and L. Stark and G. Obrecht}, title = {Multi-Screen Micro-Computer Text Display Device}, booktitle = {Proceedings International Conference on Systems, Man, and Cybernetics}, address = {Bejing}, month = aug, year = {1988}, contents = {033} } @inproceedings{BRL034, author = {C. Pedrono and B. Hannaford and G. Obrecht and L. Stark}, title = {Testing Functional Fields of View with the Multi-Screen Text Display Device {RSG}+}, booktitle = {Proceedings International Conference on Systems, Man, and Cybernetics}, address = {Bejing}, month = aug, year = {1988}, contents = {034} } @inproceedings{BRL035, author = {A.K. Bejczy and B. Hannaford and Z. Szakaly}, title = {Multi-Mode Manual Control in Telerobotics}, booktitle = {Proceedings of Romansy '88}, address = {Udine, Italy}, month = {September 12-15}, year = {1988}, contents = {035} } @inproceedings{BRL036, author = {A.K. Bejczy and B. Hannaford}, title = {Man-Machine Interaction in Space Telerobotics}, booktitle = {Proceedings Intl. Symposium on Teleoperation and Control}, pages = {135-150}, address = {Bristol, England}, month = jul, year = {1988}, contents = {036} } @inproceedings{BRL038, author = {B. Hannaford}, title = {Homeomorphic Decomposition of the 6th Order Non-Linear Model of Human Movement}, booktitle = {Proceedings 10th IEEE/EMBS}, address = {New Orleans, LA}, month = {November 4-7}, year = {1988}, contents = {038} } @article{BRL039, author = {N. Akamatsu and B. Hannaford and L. Stark}, title = {An Intrinsic Mechanism for the Oscillatory Contraction of Muscle}, journal = {Proc IEEE Intl Conf on Engineering in Med. \& Biol}, pages = {1730-1}, address = {New Orleans, LA}, month = {Nov. 4-7}, year = {1989}, abstract = {Incomplete text \& 1 new figure of experimental tremor time function.}, contents = {039} } @inproceedings{BRL040, author = {B. Hannaford and L. Wood}, title = {Performance Evaluation of a 6 Axis High Fidelity Generalized Force Reflecting Teleoperator}, booktitle = {Proceedings JPL/NASA Conference on Space Telerobotics}, publisher = {JPL Publication 89-7}, address = {Pasadena, CA}, month = jan, year = {1989}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep040.pdf}, contents = {040} } @inproceedings{BRL041, author = {B. Hannaford}, title = {Stability and Performance Tradeoffs in Bi-Lateral Telemanipulation}, booktitle = {Proceedings of IEEE Intl. Conf. on Robotics \& Automation}, volume = {3}, pages = {1764-1767}, address = {Scottsdale, AZ}, month = may, year = {1989}, contents = {041} } @inproceedings{BRL042, author = {B. Hannaford and P. Lee}, title = {Hidden Markov Model Analysis of Force/Torque Information in Telemanipulation}, booktitle = {Proceedings 1st International Symposium on Experimental Robotics}, address = {Montreal}, month = jun, year = {1989}, contents = {042} } @article{BRL043, author = {B. Hannaford}, title = {A Non-linear Model of the Phasic Dynamics of Muscle Activation}, journal = {IEEE Trans. Biomedical Engineering}, volume = {37}, number = {11}, pages = {1067-1075}, year = {1990}, abstract = {This paper presents a phasic excitation-activation (PEXA) model of the process of motoneuron excitation and the resultant activation and force development of a motor unit. The model input is an amount of depolarizing current (as when injected with an intracellular electrode) and the model output is muscle force. The model includes dynamics and nonlinearities similar to phenomena discovered experimentally by others; the firing rate response of motoneurons to steps of depolarizing current and the "catch-like enchancement" of force produced by overlapping motor neuron action potentials. The parameter values used in this model are derived from experimentally measured data and expressed in physical units, and model predictions extend to published data beyond those used in generating the model parameter values.}, contents = {043} } @article{BRL044, author = {M.H. Nam and B. Hannaford and L. Stark}, title = {Cross Talk, Muscle Synergy, and Electrode Locations and Their Effects on Electromyographic Activity in Neck Muscles}, journal = {Innov. and Techn. in Biol. and Medicine}, volume = {10}, number = {2}, pages = {233-241}, year = {1989}, abstract = {We measured head position and the surface electromyographic (EMG) activities from various locations on the back of the neck during time-optimal head movements to clarify the effects of electrode location on recorded EMG signal. To precisely record the electrode locations used, we defined the coordinate system with respect to the seventh cervical vertibrae. Location 2 where the splenius was directly below the skin shows the classical tri-phasic EMG pattern and best characterized splenius activity. Our results show that care must be exercised when interpreting surface EMG evidence in complex muscle/joint systems.}, contents = {044} } @book{BRL045, author = {B. Hannaford and L. Wood and B. Guggisberg and D. McAffee and H. Zak}, title = {Performance Evaluation of a Six-Axis Generalized Force-Reflecting Teleoperator}, publisher = {JPL Publication 89-18}, address = {Pasadena, CA 91109}, month = {June 15}, year = {1989}, contents = {045} } @incollection{BRL046, author = {B. Hannaford and L. Stark}, editor = {P. Dario and G. Sandini and P. Aebischer}, title = {Motor Control Simulation of Time Optimal Fast Movement in Man}, booktitle = {Robotics and Biological Systems: Towards a New Bionics?}, pages = {411-418}, publisher = {Springer Verlag}, year = {1990}, contents = {046} } @inproceedings{BRL048, author = {B. Hannaford and W.S. Kim}, title = {Force Reflection, Shared Control, and Time Delay in Telemanipulation}, booktitle = {Proceedings, IEEE Intl. Conference on Systems, Man, \& Cybernetics}, address = {Cambridge, MA}, month = nov, year = {1989}, abstract = {Time delays of between 2 ms and 4096 ms were introduced between master and slave manipulators in an advanced 6 dof force reflecting telemanipulation system. The effects of the imposed delay were quantified in terms of completion time (CT) and sum-of-squared force (SOSF) with six test operators and two modes of control: Kinesthetic Force Feedback (KFF), and Shared Compliant Control (SCC). KFF applies forces and torques proportional to those sensed by the slave robot to the human operator through the master. SCC uses the force/torque information entirely at the slave side to implement a variation on Impedance Control in parallel with the operator's position commands. Experiments measured effects of human operator grasp variation on stability of contact with KFF. CT and SOSF performance in a peg-in-hole task decreased linearly with imposed time delay using KFF and decreased at a lower rqte with SCC. SCC enabled task performance at delays above 1 second.}, contents = {048} } @inproceedings{BRL049, author = {W.S. Kim and B. Hannaford and A. Bejczy}, title = {Shared Compliance Control and Time Delay in Telemanipulation}, booktitle = {Preprint: Proceedings, First Intl. Symposium on Measurement and Control in Robotics}, address = {Houston TX}, month = {June 20-22}, year = {1990}, abstract = {Shared compliance control (SCC), which allows the human operator to interact with a compliantly controlled telerobot hand, has been implemented by a low- pass-filtered force/torque feedback in the robot side. Unlike force reflection or kinesthetic force feedback (KFF), SCC does not have the instability problem casued by a long communication time delay, since force feedback is done locally in the robot side. To evaluate SCC in comparison with KFF, peg-in-hole tasks were performed with time delays from 2 ms to 4096 ms introduced between the master and slave arm. The effects of the time delay were quantified in terms ofcompletion time and sum-of-squared force with six test operators for both SCC and KFF. The experimental results demonstrate the superiority of SCC over KFF for time-delayed telemanipulation. Increase rates of both task completion time and sum-of-squared force with increased time delay were much lower with SCC than with KFF. Only SCC enabled task performance at delays about 1 second, indicating that SCC is a promising and essential scheme for time-delayed telemanipulation.}, contents = {049} } @article{BRL050, author = {B. Hannaford}, title = {Method and Apparatus for Multiplexing Switch Signals}, journal = {US Patent No. 4,884,070}, month = {Nov. 28}, year = {1989}, annote = {http://www.patents.ibm.com/details?patent\_number=4884070}, abstract = {Apparatus for multiplexing switch state signals comprises a plurality of switches and parallel weighted resistors connected in series between circuit ground and a node at a utlitization device. The resistors are weighted as a function of a power of the same base, such as the power of the base 2, for coding the multiplexed switch state signals. A constant current source connected between the node and circuit ground drives current over a single cable conductor through the resistor. Each switch may be independently closed to change the switch state voltage signals multiplexed to the node. An analog-to- digital converter connected between the node and circuit ground demultiplexes the switch state signals received as at the node and provides a switch state signals received at the node and provides a switch state signal at each analog- to-digital output corresponding to the state of the switches at the moment. A potentiometer may replace a resistor and bypass switch combination in a position where the potentionmeter has a maximum value of the lowest power of the base in order to multiplex a true analog voltage signal while switch state signals are unambiguously coded and multiplexed. The potentiometer in the least significant position permits the analog value to be in the range from 0 to a maximum corresponding to the least significant position of the switch state encoding. The invention may be used in redundancy systems by duplicating the invention with corresponding switches in each duplication ganged to open and close simultaneously upon operation of a pushbutton switch.}, contents = {050} } @article{BRL051, author = {B. Hannaford and L. Wood and D. McAffee and H. Zak}, title = {Performance Evaluation of a Six Axis Generalized Force Reflecting Teleoperator}, journal = {IEEE Transactions on Systems, Man, and Cybernetics}, volume = {21}, pages = {620-633}, year = {1991}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep051.pdf}, abstract = {Recent work in real-time distributed computation and control has culminated in a prototype force-reflecting telemanipulation system having dissimilar master (cable-driven force-reflecting hand controller) and slave (PUMA 560 robot with customer controller), extremely high sampling rate (1000 Hz) and low loop computation delay (5 ms). In a series of experiments with this system and five trained test operators covering more than 100 h of teleoperation, performance in a series of generic and application-driven tasks with and without force feedback was measured, and with control shared between teleoperation and local sensor referenced control. Measurements defining task performance include 100-Hz recording of six-axis force-torque information, task completion time, and visual observation of predefined task errors. The tasks consisted of high precision peg- i developed for prediction and analysis of sensor information recorded during robotic performance of tasks by telemanipulation. The model uses the Hidden Markov Model (stochastic functions of Markov nets: HMM) to describe the task structure, the operator or intelligent controller's goal structure, and the sensor signals such as forces and torques arising from interaction with the environment. The Markov process portion encodes the task sequence/subgoal structure, and the observation densities associated with each subgoal state encode the expected sensor signals associated with carrying out that subgoal. Methodology is described for construction of the model parameters based on engineering knowledge of the task. The Viterbi algorithm is used for model based analysis of force signals measured during experimental teleoperation and achieves excellent segmentation of the data into subgoal phases. The Baum-Welch algorithm is used to identify the most likely HMM from a given experiment. The HMM achieves a structured knowledge-based model with explicit uncertainties and mature, optimal identification algorithms.}, contents = {051} } @article{BRL052, author = {B. Hannaford and P. Lee}, title = {Hidden Markov Model of Force Torque Information in Telemanipulation}, journal = {International Journal of Robotics Research}, volume = {10}, number = {5}, pages = {528-539}, year = {1991}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep052.pdf}, abstract = {A new model is developed for prediction and analysis of sensor information recorded during robotic performance of tasks by telemanipulation. The model uses the Hidden Markov Model (stochastic functions of Markov nets: HMM) to describe the task structure, the operator or intelligent controller's goal structure, and the sensor signals such as forces and torques arising from interaction with the environment. The Markov process portion encodes the task sequence/subgoal structure, and the observation densities associated with each subgoal state encode the expected sensor signals associated with carrying out that subgoal. Methodology is described for construction of the model parameters based on engineering knowledge of the task. The Viterbi algorithm is used for model based analysis of force signals measured during experimental teleoperation and achieves excellent segmentation of the data into subgoal phases. The Baum-Welch algorithm is used to identify the most likely HMM from a given experiment. The HMM achieves a structured knowledge-based model with explicit uncertainties and mature, optimal identification algorithms.}, contents = {052} } @incollection{BRL053, author = {B. Hannaford and J.M. Winters}, editor = {J.M. Winters}, title = {Actuator Properties and Movement Control: Biological and Technological Models}, booktitle = {Multiple Muscle Systems}, publisher = {Springer Verlag}, year = {1990}, abstract = {Actuation is the process of conversion of energy to mechanical form. A device that accomplishes this conversion is an actuator. There are many types of actuators, with most including energy transformation through multiple forms. Of course an equally vital part of the definition of an actuator is controllability; the actuator's conversion of energy must be modulated by a control input. Galvani demonstrated that muscle activity could be electrically modulated. We now know that this involves an electrical signal that, through a series of steps that are rate-limited by the influx-efflux of calcium, modulates acto-myosin interaction. In the 1920s Hill, Fenn, and their colleagues broke new ground by subjecting muscle to the thermodynamic analysis developed for the rational design of energy conversion devices such as steam engines. We now have a fairly good idea of how chemical energy stored in the form of ATP is converted to mechanical work. Thus, we can view muscle as an actuator. This chapter will examine the mechanical properties of muscle actuators in the context of technological actuators such as those used in robot manipulators. The goals of the chapter are: i) to elucidate and contrast the dynamic properties of various technological actuators, with concentration on how other actuators differ from biological muscle; and ii) to elucidate how actuator properties influence system control strategies.}, contents = {053} } @incollection{BRL054, author = {B. Hannaford}, editor = {C. Leondes}, title = {Kinesthetic Feedback Techniques in Teleoperated Systems}, booktitle = {Advances in Control and Dynamic Systems}, volume = {40-2}, pages = {1-32}, publisher = {Academic Press}, address = {San Diego}, year = {1991}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep054.pdf}, abstract = {Teleoperation, the ability to perform physical manipulations of objects from a distant control point, is the newest "tele" technology (coming after telegraphy, telephony, and television). Teleoperation was first reduced to practice by Goertz in the late 1940's. Even at that time it was recognized that controlling the "slave" (remote) robot to track the position and orientation of a "master" manipulator held in the operator's hand was insufficient to effectively perform remote tasks. An essential feature of useful systems was the feedback* of force information to the operator arising from the interaction between the slave and its environment. The essential quality for effective remote manipulation is the replication of both force and incremental motion at the mast and slave end effectors. A feedback system implementing this behavior is said to be "Kinesthetic." Kinesthesia is defined as: "The sensation of movement or strain in muscles, tendons, and joints."}, contents = {054} } @article{BRL055, author = {W.S. Kim and B. Hannaford and A.K. Bejczy}, title = {Force-Reflection and Shared Compliant Control in Operating Telemanipulators with Time Delay}, journal = {IEEE Transactions on Robotics \& Automation}, volume = {8}, number = {2}, pages = {176-185}, year = {1992}, abstract = {Shared compliant control has been incorporated into an advamced six-degree-of- freedom (6-DOF) force-reflecting telemanipulation system. With this system we have investigated the effect of time delay on human telemanipulation task performance. Time delays of between 2 and 4096 ms were introduced between master and slave arms, and high-precision peg-in-hole tasks were performed by six test operators with two modes of control: kinesthetic force feedback (KFF), and shared compliant control (SCC). Task performance was quantified in terms of the completion time (CT) and the sum of square forces (SOSF). In KFF, the operator feels forces and torques proportional to those sensed by the telerobot through the force-reflecting hand controller. Due to the instability problem, force reflection cannot be used at time delays above 0.5 to 1 s. By contrast, the force feedback loop in SCC resides entirely in the robot side, and the communication delay does not cause any stability problem. SCC enables the operator to control the telemanipulator having a compliant hand, which softens contact forces between the robot hand and objects. The experimental results demonstrate the superiority of SCC over KFF for time-delays telemanipulation. SCC has significantly lower rates of increase then KFF in both CT and SOSF with time delay. Only SCC enabled task performance at delays above 1 s, indicating that SCC is a promising and essential scheme for time-delayed manipulation. Constant force maintenance tasks were also performed to investigate the effect of time delay on the stability of force reflection. SCC also has beneficial effects on telemanipulation without time delay.}, contents = {055} } @inproceedings{BRL057, author = {B. Hannaford}, title = {Scaling, Impedance, and Power Flows in Force Reflecting Teleoperation}, booktitle = {Proceedings ASME Winter Annual Meeting}, volume = {26, Robotics Research}, pages = {229-232}, address = {Dallas}, month = nov, year = {1990}, abstract = {The effects of position scaling and force scaling on force reflecting telemanipulation (teleoperation) are described with reference to the hybrid two- port network model of teleoperation. These effects are important in applications with large differences of scale such as in biomedical micro- manipulation. The effects of scale factors on impedance perception and the flow and dissipation of power in the teleoperation system are discussed.}, contents = {057} } @inproceedings{BRL058, author = {B. Hannaford and P. Lee}, title = {Multi-Dimensional Hidden Markov Model of Telemanipulation Tasks with Varying Outcomes}, booktitle = {Proceedings IEEE Intl. Conf. Systems Man and Cybernetics}, address = {Los Angeles, CA}, month = nov, year = {1990}, abstract = {Three multi-step teleoperation tasks were successfully modeled with a Hidden Markov Model (HMM). The model was then used to correctly identify the sequence of task progression from the recorded sensor data. Previous work with HMMs was extended by the generalization of the model to encompass multidimensional sensor signals consisting of a mix of force, torque, and position signals. The addition of multi-dimensional sensor information significantly improved the ability of the Viterbi decoding algorithm to identify the series of events.}, contents = {058} } @inproceedings{BRL059, author = {P. Lee and A. Bejczy and P. Schenker and B. Hannaford}, title = {Telerobot Configuration Editor}, booktitle = {Proceedings IEEE Intl. Conf. Systems Man and Cybernetics}, address = {Los Angeles, CA}, month = nov, year = {1990}, abstract = {Telerobot Configuration Editor (TCE) is an iconic graphical user interface based on X Windows environment. TCE offers an easy way to configure a complex telerobotic system, which requires numerous parameter settings to access the full capabilities of the system. The screen layout design of TCE is done by utilizing various visual coding mechanisms, such as color and brightness, to make the hierarchical structure of the TCE visible to the user. Two key features, the macro configuration buttons and the system access levels, have been incorporated into TCE design. The macro configuration buttons can store the full or a partial set of configuration parameters, and these macros can be used as high level configuration parameters that are well suited to the physicaltasks such as peg insertion task. The system access levels limit the user access to the system, based on their ability and their need. These two features allow TCE to be a flexible and effective interface suited to be used by any userthat needs to configure a telerobotic system.}, contents = {059} } @inproceedings{BRL061, author = {P.H. Marbot and B. Hannaford}, title = {Mini Direct Drive Arm for Biomedical Applications}, booktitle = {Proceedings of ICAR 91}, pages = {859-864}, address = {Pisa Italy}, month = jun, year = {1991}, abstract = {The potential of electromagnetic actuation in very small machine has been investigated. It has been compared to the newer technology of electrostatic micro-machines. Considerations on energy density, scaling capability, heat dissipation and actual geometry of a design have lead us to the conclusion that electromagnetic actuators are also competitive in the submillimeter range. We proceeded with the description of our 4 degree of freedom, direct drive, force feedback mini-robot. It uses winchester disk drive technology, which is compact, powerful, clean and getting smaller, year after year. This robot could be the prototype of a family of mini-robots adapted to micro-surgery, biology and clean-room environment.}, contents = {061} } @article{BRL062, author = {B. Hannaford}, title = {Resolution-First Scanning of Multi-Dimensional Spaces}, journal = {CVGIP: Graphical Models and Image Processing}, volume = {55}, number = {5}, pages = {359-369}, month = sep, year = {1993}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep062.pdf}, abstract = {Three methods are introduced for generating complete scans of multidimensional spaces. The traditional method is to use a raster (typically generated by nested iteration) which generates points at the maximum resolution and fills the space slowly. New methods are desirable, because in many applications it is desirable for the scanned points to be distributed throughout the space and for the resolution to increase with the number of points scanned. Three simple methods are introduced in this paper. Two of the methods are members of a class of methods in which the reverse-bit-order operator maps points from "R(esolution)-space" to the desired space. In "R-space" the distance from the origin determines the resolution level of the scanned point. The two scans occupy points in such a way that a distance measure such as the L 1 norm or the L (infinity) norm increases with the progress of the scan. The third method uses iteration of primitive polynomials modulo 2 to generate a nonrepeating sequence of binary numbers which eventually fills the space. This method is most computationally efficient, but the L (infinity) norm method generates partial scans which completely sample the space at intermediate levels of resolution. Applications are expected in scientific visualization, graphics rendering, multicriterion optimization, and progressive image transmission.}, contents = {062} } @inproceedings{BRL063, author = {B. Hannaford}, title = {Hidden Markov Model Analysis of Manufacturing Process Information}, booktitle = {Proc. IROS 1991}, address = {Osaka, Japan}, month = nov, year = {1991}, abstract = {A method is presented for using Hidden Markov Models (HMMs) for the analysis of force, torque, and position signals from sensors in manufacturing machines. The HMM can detect the transitions between contact states and compute a measure of the task quality using a model of the task developed by the manufacturing engineer and optimized on training data. The HMM method has been evaluated in extensive experimentation with teleoperation and the results suggest even higher effectiveness in automation and manufacturing applications.}, contents = {063} } @article{BRL064, author = {C.P. Chou and B. Hannaford}, title = {Dual Stable Point Model of Muscle Activation and Deactivation}, journal = {Biological Cybernetics}, volume = {66}, pages = {511-523}, year = {1992}, abstract = {Two dynamic models of muscle activation and deactivation based on the concepts of ion transport, reaction rates, and muscle mechanics are proposed. Storage release and uptake of calcium by the sarcoplasmic reticulum, and a two-step chemical reaction of calcium and troponin are included in the first model. This is a concise version of the complex chemical reactions of muscle activation and deactivation in sarcoplasm. The second model is similar to the first, but calcium-troponin reactions are simplified into two non-linear rates functions. Due to these nonlinear dynamics, the second model can explain the catch-like enhancement of isometric force response. Simulation results which match experimental data are shown. Also, two new phenomena which need further experiment to verify are predicted by the second model.}, contents = {064} } @inproceedings{BRL065, author = {D. Kung and J. Parsons and B. Hannaford}, title = {Visualization of Manipulability with Mathematica}, booktitle = {Proceedings IASTED Control \& Robotics}, address = {Vancouver}, month = aug, year = {1992}, abstract = {A software package has been developed in Mathematica to perform analysis of kinematic manipulability for arbitrary serial chain robot manipulators. The program contains heuristics to locate the optimal frame in which to project the coordinate free representation of the Jacobian matrix. The resulting matrix is then derived in symbolic form and expressions are reduced to simplest form. Manipulability is then computed numerically using Mathematica's singular value decomposition function. Depending on the selected frame, the computation time for the reduced, symbolic Jacobian matrix varied over almost four orders of magnitude for an 8-dof manipulator model. Further features of the software include color graphics visualization of the manipulability of the manipulator as it moves through a specified trajectory. A stick-figure representation of the manipulator is generated and stored in symbolic form. It is then rendered at each position in the trajectory, and colored according to it's manipulability at the current point.}, contents = {065} } @inproceedings{BRL066, author = {P. Bhatti and P.H. Marbot and B. Hannaford}, title = {Microscopic Pick and Place with the Mini-Direct Drive Arm}, booktitle = {SPIE Telemanipulation Symposium}, address = {Boston}, month = nov, year = {1992}, abstract = {A mini gripper attachment has been fabricated for a mini direct drive robot arm. Mounted on the robot, it has successfully performed pick and place operations with grains of sand under teleoperated conditions. The mini robot serves to precisely position the gripper, and a needle-like finger of the gripper deflects so the fingers can grip objects up to 0.5mm. The gripper finger capable of motion is fabricated with a piezoelectric bimorph crystal which deflects with an applied DC voltage. The experimental results are promising, and the mini gripper may be modified for future biomedical and clean room applications.}, contents = {066} } @inproceedings{BRL067, author = {P.H. Marbot and B. Hannaford}, title = {The Mechanical Spindle: a Replica of the Mammalian Muscle Spindle}, booktitle = {Proceedings, IEEE Conference on Engineering in Medicine and Biology}, address = {San Diego, CA}, month = oct, year = {1993}, abstract = {The goal of the recently initiated anthroform arm project is to understand the manipulation capabilities of the human arm through the development of a dynamically accurate replica arm. One key element is the mammalian muscle spindle responsible for position and velocity feedback. This paper describes the important spindle features that we are attempting to copy, as well as the mechanical and software aspects of our first prototype. The model and prototype include active modulation of spindles' non-linear response which models the gamma efference. The sensor that was developed can also be used for other applications, and shows unique adaptive properties.}, contents = {067} } @inproceedings{BRL068, author = {I. MacDuff and S. Venema and B. Hannaford}, title = {The Anthroform Neural Controller: An Architecture for Spinal Circuit Emulation}, booktitle = {Proceedings of IEEE International Conference on EMBS}, pages = {1289,90}, address = {Paris}, year = {1992}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep068.pdf}, abstract = {Existing robotic manipulator and controller designs compare unfavorably to the human arm when performing tasks in unstructured environments. Traditionally, "anthropomorphic" designs have focused on replicating only the kinematics of the human arm. In contrast, we describe a versatile parallel computing architecture for emulating the spinal circuits of the human nervous system in conjunction with a dynamically realistic actuated arm model. This design is based on the structural constraints of the nervous system, and consists of a special purpose digital bus which implements connections between simulated neuron pools. The processing elements are circuit cards based on the TMS 320C30 digital signal processing chip. The system may be expanded to 256 processor cards, supporting a total of 1024 computational modes that are interconnected every millisecond.}, contents = {068} } @article{BRL069, author = {W.C. Wang and M. Afromowitz and B. Hannaford}, title = {Technique for Mechanical Measurements Using Optical Scattering From a Micro-Pipette}, journal = {IEEE Transactions on Biomedical Engineering}, volume = {41}, pages = {298-304}, month = mar, year = {1994}, abstract = {This communication proposes an optical method using forward light scattering to measure the deflection of a micropipette from a normal contact force with a small elastic solid, and the damping coefficient of a small fluid sample through a dynamic interaction with the pipette. An analytical and experimental study of this sensor is performed and described for each property. Topics covered include: 10 forward light scattering technique for determining the diameter of a micropipette (using exact and simplified geometric interference theories); 2) deflection measurement and analysis on the pipette-sample system using the finite element method; and 3) equivalent damping coefficient and resonant frequency measurement of the pipette-fluid system and its numerical solution derived from the finite element model. A companion of the experimental results and the analytical results is included to provide the means for analyzing the potential of this new method.}, contents = {069} } @inproceedings{BRL070, author = {I. MacDuff and S. Venema and B. Hannaford}, title = {The Anthroform Neural Controller: {A} System for Detailed Emulation of Neural Circuits}, booktitle = {Proceedings, IEEE International Conference on Systems, Man, and Cybernetics}, volume = {1}, pages = {117-22}, address = {Chicago, IL}, month = oct, year = {1992}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep070.pdf}, abstract = {Existing robotic manipulator and controller designs compare unfavorably to the human arm when performing tasks in unstructured environments. So-called "anthropomorphic" designs have tried to improve robot performance in these domains by replicating the kinematic structure of the human arm while continuing to use traditional actuation and control techniques. In this paper we describe a versatile parallel computing architecture for emulating the spinal circuits of the human nervous system. When used in conjunction with a dynamically realistic replica of the human arm, this controller will provide a versatile tool for studying human moto-sensory control. The design is based on the structural constraints of the nervous system and consists of a special purpose digital bus which implements connections between simulated neurons running on TMS 320C30 digital signal processors (DSPs). The system supports up to 1024 individual neuron models, each connected to every other at least once every millisecond. These neuron models may be distributed over as many as 256 processor circuit cards, each supporting an interface for high level control from a host and another for input and output functions.}, contents = {070} } @inproceedings{BRL072, author = {C.A. Lawn and B. Hannaford}, title = {Performance Testing of Passive Communication and Control in Teleoperation with Time Delay}, booktitle = {Proc. IEEE Intl. Conf. on Robotics and Automation}, volume = {3}, pages = {776-781}, address = {Atlanta, GA}, month = may, year = {1993}, abstract = {Advanced application of remote manipulation or teleoperation will require kinesthetic feedback of force and torque information from slave robot to master hand controller. In outer space and terrestrial remote control, there is unavoidable time delay between master and slave. This study evaluates the performance of several candidate control laws for a single-axis testbed telemanipulation system in the presence of up to 1 second of time delay. Algorithms tested include communication laws based on passivity theory. Results indicated that task completion time was as much as 50\% greater with the passivity based methods.}, contents = {072} } @article{BRL075, author = {M. Shoemaker and B. Hannaford}, title = {A Study and Model of the Role of the Renshaw Cell in Regulating the Transient Firing Rate of the Motoneuron}, journal = {Biological Cybernetics}, volume = {71}, pages = {251-262}, year = {1994}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep075.pdf}, abstract = {This study sought to investigate the role of the Renshaw cell with respect to transient motoneuron firing. By studying the cat motoneuron and Renshaw cell, several low-order lumped parameter models were developed that simulate the known characteristics of the injected input current vs. firing rate. The neuron models in the Renshaw cell inhibition configuration were tuned to fit experimental data from cat motoneurons. Models included both linear versions and those with sigmoidal nonlinearities. Results of the simulation indicate that the motoneuron itself provides the adaptation seen in its firing rate and that the Renshaw cell's role is primarily to fine-tune the motoneuron's adaptation process.}, contents = {075} } @inproceedings{BRL076, author = {P. Buttolo and D.Y. Hwang and B. Hannaford}, title = {Hard Disk Actuators for Mini-Teleoperation}, booktitle = {Proc. SPIE Telemanipulator and Telepresence Technologies Symposium}, pages = {55-61}, address = {Boston}, month = {October 31}, year = {1994}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep076.pdf}, abstract = {Hard disk drives have evolved rapidly with computer miniaturization into highly compact and integrated electromechanical systems. Hard drives contain many precision mechanical parts which may prove useful in the design of small precision robots. The advantages of parts taken from hard disks include low cost, miniaturization, high quality, and for some applications, cleanliness. We report the results of engineering tests on flat coil head positioning actuators taken from hard drives of sizes ranging from a 5.25" to 1.8" media diameter. We also perform a simple analysis which suggests that requirements for torque per unit mass are lower for small robot arms. The results suggest ways that hard disk actuators can be utilized in mini robotic designs and points the way towards improved versions of these designs for robotic purposes.}, contents = {076} } @inproceedings{BRL077, author = {C.P. Chou and B. Hannaford}, title = {Static and Dynamic Characteristics of McKibben Pneumatic Artificial Muscles}, booktitle = {Proc. IEEE Intl. Conf. on Robotics and Automation}, address = {San Diego, CA}, month = may, year = {1994}, abstract = {This paper reports mechanical testing and modeling results for the McKibben artificial muscle pneumatic actuator. This device first developed in the 1950's contains an expanding tube surrounded by braided cords. We report static and dynamic length-tension testing results and derive a linearized model of these properties for three different models. The results are briefly compared with human muscle properties to evaluate the suitability of McKibben actuators for human muscle emulation in biologically based robot arms.}, contents = {077} } @article{BRL079, author = {P. Loughlin and J. Pitton and B. Hannaford}, title = {Approximating Time-Frequency Density Functions via Optimal Combinations of Spectrograms}, journal = {IEEE Signal Processing Letters}, volume = {1}, number = {12}, pages = {199-202}, year = {1994}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep079.pdf}, abstract = {We demonstrate that two previously proposed methods for combining the information content from multiple spectrograms into a single, positive time- frequency function are optimal in a cross-entropy sense. The goal in combining the spectrograms is to obtain an improved approximation of the joint time- frequency signal density by overcoming limitations of any single spectrogram. An example of each method is provided, and results are compared with spectrograms and a Cohen-Posch time-frequency density (TFD) of a nonstationary pulsed tone signal. The proposed combinations are effective and can be efficiently computed.}, contents = {079} } @article{BRL081, author = {P. Buttolo and P. Braathen and B. Hannaford}, title = {Sliding Control of Force Reflecting Teleoperation: Preliminary Studies}, journal = {PRESENCE}, volume = {3}, number = {2}, pages = {158-172}, year = {1994}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep081.pdf}, abstract = {In this paper, sliding mode non-linear control is applied to force reflecting teleoperation. Various forms of the sliding mode control law are derived for force feedback master manipulator with an arbitrary factor for force and position scaling. Experiments were performed on a one axis test system and frequency domain hybrid 2-port matrices are measured and compared between the sliding mode controller and a classical position error based feedback controller. Time domain experiments are also performed. The model based portion of the sliding mode controller was shown to be responsible for most of its performance improvement, but the non-linear `sliding' component was essential for steady state position accuracy.}, contents = {081} } @inproceedings{BRL084, author = {B. Hannaford and P.H. Marbot and M. Moreyra and S. Venema}, title = {A 5-Axis Mini Direct Drive Robot for Time Delayed Teleoperation}, booktitle = {Proc. Intelligent Robots and Systems (IROS 94)}, volume = {1}, pages = {555-562}, address = {Munich}, month = sep, year = {1994}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep084.pdf}, abstract = {A previously developed 3 axis mini direct drive robot has been enhanced with two additional direct drive axes for general positioning and orientation of an axially symmetric tool. The arm has a work volume of about 50 cc and will have 5-10 micron or better resolution and repeatability. The arm forms an initial prototype for the NASA/University of Washington MicroTrex flight telerobotics experiment. The contemplated terrestrial applications include handling sub-microliter liquid samples for electrophoresis, and micro-manipulation with scaled force reflection.}, contents = {084} } @inproceedings{BRL085, author = {D.Y. Hwang and B. Hannaford}, title = {Modeling and Stability analysis of a Scaled Telemanipulation}, booktitle = {Proceedings RO-MAN 94}, address = {Nagoya}, month = jul, year = {1994}, abstract = {When the scaled teleoperation is used, the stability issue becomes important due to the high gains in position or force scaling. We used two experimental methods to identify the stable region of position and force scaling factors of a one-axis system having 4000:1 force scaling capability. We used a simple classical teleoperation control law. An indirect closed loop approach with ARX technique was used to model the non-linear slave system with a flexible printed circuit cable.}, contents = {085} } @inproceedings{BRL086, author = {B. Hannaford and J.M. Winters and C.P. Chou}, title = {The Anthroform Biorobotic Arm}, booktitle = {Video Proceedings, IEEE Intl. Conf. on Robotics and Automation}, address = {San Diego, CA}, month = may, year = {1994}, abstract = {A video tape: The Anthroform Biorobotic Arm is a biomechanically accurate replica of the human arm designed to assist in the study of neural control mechanisms in the spinal cord, and as a pre-prototype for future advanced robot arms. The structure ofthe arm is based as much as possible on the human arm. For example, the bones are cast from fiberglass epoxy from human cadaver bones, the joints are surgical replacement joints donated by Howmedica Inc., and the ligaments are made from selected, tested, man-made knit fabrics having similar non-linear stiffness to actual ligaments. The actuators are McKibben pneumatic braided actuators custom fabricated at Catholic University to match specific muscle properties. Although it still differs from the human arm in several key aspects, the Anthroform arm is the first actuated arm whose design is based on the anatomy and dynamics of the human arm. It will be used in conjunction with a Digital Signal Processor based computing system to study biologically realistic models of spinal neural circuits. Support for this project was provided by the US Office of Naval Research.}, contents = {086} } @inproceedings{BRL087, author = {K. Kuhn and B. Hannaford}, title = {A "Hands-On" Course in Consumer Electronics}, booktitle = {Proceedings Workshop on Mechatronics Education}, address = {Stanford California}, month = jul, year = {1994}, abstract = {There is still a large gap between the academic design approach taught to our students and the real world of competitive product design. In spite of program upgrades which heavily emphasize design, the termination of many of our students' advanced design projects is still a maze of breadboards connected together with wires which randomly wander off to input sensors or output displays. Clearly, there is a big step missing between the disorganized connection of components which concludes a design project; and the sleek, injection molded Sony Discman that is playing in the design laboratory beside the workbench. In an effort to close the gap between engineering education and modern consumer electronics product design, the Department of Electrical Engineering at the University of Washington has initiated a "reverse- engineering" course in Consumer Electronics. The first offering of the course was made during Winter 1994 as part of the College of Engineering honors program.}, contents = {087} } @inproceedings{BRL088, author = {B. Hannaford and S. Venema and A.K. Bejczy}, title = {{MICROTREX}: Micro-Telerobotic Flight Experiment}, booktitle = {Proceedings AIAA Space Programs and Technologies Conference; AIAA 94-4509}, address = {Huntsville, Al}, month = sep, year = {1994}, annote = {http://brl.ee.washington.edu/BRL\_Pubs/Pdfs/Rep088.pdf}, abstract = {The MICROTREX (Micro Telerobotic Experiment) project proposes to use a small flight telerobot in low earth orbit to perform ground-controlled telerobotics experiments. These experiments will evaluate the effectiveness of ground-based control of an orbital telerobot in the presence of variable communications time-delay using a variety of control techniques including closed-loop force feedback position control. The small, lightweight flight system consisting of a micro-scale (50-cm3 work-volume) direct-drive six degree of freedom manipulator, an experiment task board, and computer control and communications hardware will be used to minimize flight mass/power requirements. The project is currently in "Phase A" status in the NASA In Space Technology Experiments Program (INSTEP).}, contents = {088} } @article{BRLTh001, author = {P.H. Marbot}, title = {Mini Direct Drive Robot for Biomedical Applications}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = aug, year = {1991}, contents = {Th001} } @article{BRLTh002, author = {C.P. Chou}, title = {Dual Stable Point Model of Muscle Activation and Deactivation}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = nov, year = {1991}, contents = {Th002} } @article{BRLTh003, author = {W.C. Wang}, title = {A New Optical Microsensor for Mechanical Detection Using Scattering of a Micro-Pipette}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = may, year = {1992}, contents = {Th003} } @article{BRLTh004, author = {C.A. Lawn}, title = {Design and Construction of a Single-Axis Master-Slave Teleoperation System and The Performance Evaluation of Control Algorithms and Passive Communication Laws with Time Delay}, journal = {MSME Thesis}, publisher = {University of Washington, Department of Mechanical Engineering}, month = aug, year = {1992}, contents = {Th004} } @article{BRLTh005, author = {P. Braathen}, title = {Design and Evaluation of Nonlinear Sliding Mode Control for Manipulators in a Bilateral Teleoperation System}, journal = {MSEE Thesis}, publisher = {Norwegian Institute of Technology / University of Washington}, month = feb, year = {1993}, abstract = {First, the dynamics of a manipulator is developed and a multivariable sliding mode controller for a manipulator is simulated. The controller's ability to compensate for nonlinearities and uncertainties in the dynamics of the manipulator is investigated. A method is presented for using sensor information to dynamically change the controller without adapting parameters in the model. Next, experiments are done on a single axis teleoperation system. A sliding mode controller is implemented in the system, and a method for evaluation and comparison between different controllers is presented. Finally, experiments are done that show the differences between the sliding mode controller and two linear controllers.}, contents = {Th005} } @article{BRLTh006, author = {M. Shoemaker}, title = {A Study and Model of the Role of the Renshaw Cell in Regulating the Transient Firing Rate of the Motoneuron}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = jun, year = {1993}, annote = {http://brl.ee.washington.edu/publications/Th006.pdf}, abstract = {This research sought to investigate the role of the Renshaw Cell with respect to transient motoneuron firing. By studying the cat motoneuron and Renshaw Cell, which interact to form recurrent inhibition, several low order lumped parameter models were developed that simulate known characteristics of the injected input current vs. firing rate phenomena. The neuron models, in the Renshaw Cell inhibition configuration, were tuned to fit experimental data from cat motoneurons. Results of the simulation indicate that the motoneuron itself porvides the adaptation seen in its firing rate and the Renshaw Cell's role may be primarily to fine-tune the motoneuron's adaptation process.}, contents = {Th006} } @article{BRLTh007, author = {P. Bhatti}, title = {The {SCVMS}: {A} Single Chip Velocity Measurement System for Optical Shaft Encoders}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = aug, year = {1993}, abstract = {The SCVMS provides a new hardware-based approach to velocity measurement for optical shaft encoders. The design incorporates features which give accurate velocity readings over a large range of velocities (200,000 to 0.5 transitions per second). The design is implemented in a single chip Field-Programmable-Gate Array (FPGA), resulting in low cost, low chip-count, and user reconfigurability. Since this design is implemented in hardware, a significant reduction in computing requirements is realized as compared to traditional software-based velocity measurement methods. The design is well suited for use in motion control systems and robots for industrial and biomedical applications.}, contents = {Th007} } @article{BRLTh008, author = {D.S. Smith}, title = {Kinematic Do-Ability for Manipulator Analysis}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = jan, year = {1994}, contents = {Th008} } @article{BRLTh009, author = {M.R. Moreyra}, title = {Design of a Five Degree of Freedom Direct Drive Mini-Robot Using Disk Drive Actuators}, journal = {MSME Thesis}, publisher = {University of Washington, Department of Mechanical Engineering}, month = jun, year = {1994}, contents = {Th009} } @article{BRLTh010, author = {S.C. Venema}, title = {A Kalman Filter Calibration Method for Analog Quadrature Position Encoders}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = jun, year = {1994}, annote = {http://brl.ee.washington.edu/publications/Th010.pdf}, abstract = {A method is described and validated for the automatic calibration of analog sine-wave quadrature sensors, such as optical encoders, embedded in a functioning system. The algorithm uses a Kalman filter to estimate the true position of the direct-drive actuated joint using a model of it's dynamics, an applied actuator command, and measurements from the uncalibrated sensor. From the estimated true position, a lookup table is constructed which corrects sensor errors. Our results indicate that this method achieve accuracies typical of interferometric calibration, without requiring an external measurement device. The accuracy is surprisingly robust to modeling errors.}, contents = {Th010} } @article{BRLTh011, author = {F. Boe}, title = {An Iterative Trajectory Shaping Algorithm based on Run-Time Results}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = jun, year = {1994}, contents = {Th011} } @article{BRLTh012, author = {D. Kung}, title = {Hidden Markov Model with Explicit Duration and its Application to Robotic Task Segmentation}, journal = {MSEE Thesis}, publisher = {University of Washington, Department of Electrical Engineering}, month = jun, year = {1994}, contents = {Th012} } @misc{BRL999, author = {{XXX}}, title = {{YYY}}, institution = {XXX}, year = {ZZZ}, contents = {999} } @article{Y??, author = {{Y}}, title = {X}, institution = {Y}, journal = {B}, year = {C}, abstract = {x} }