% % converted from refer format by refer-to-bibtex 0.9.3 -- 20:21, 30 Apr 108 % r2b t2 % @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/publications/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/publications/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/publications/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/publications/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/publications/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/publications/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/publications/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/publications/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} } @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/publications/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} } @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} } @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/publications/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/publications/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/publications/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{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/publications/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} } @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/publications/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} } @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/publications/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} } @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/publications/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/publications/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} } @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/publications/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} } @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/publications/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} } @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/publications/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} } @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/publications/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} } @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/publications/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} } @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} } @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}, 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} } @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/publications/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{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/publications/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{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/publications/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{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/publications/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{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/publications/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{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} } @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} } @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/publications/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{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/publications/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{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/publications/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} } @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/publications/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{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/publications/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} } @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/publications/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} } @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} } @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/publications/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} } @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/publications/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} } @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/publications/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{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/publications/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{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/publications/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{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/publications/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{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/publications/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} } @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} } @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{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/publications/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{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/publications/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{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/publications/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} } @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/publications/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{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/publications/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{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/publications/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{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/publications/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} } @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/publications/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{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/publications/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} } @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/publications/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} } @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/publications/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{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/publications/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,