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Haptics Interfaces

Linear Haptic Display (LHD)

Abstract

The Linear Haptic Display (LHD) - Excalibur is a 3 degree-of-freedom haptic device, built for maximum workspace, force output, and structural stiffness.  It was designed and manufactured by Haptic Technologies, Inc. of Seattle, WA.  Its hallmark is a patented steel cable transmission system which enables high forces and high rigidity in the three orthogonal axis of translational motion.  The motors are mounted on the base of the mechanism, so that only light linkage elements move with the handgrip.

UW LHD with integrated handgrip force sensor

Boeing LHD with F-18 flight stick

Specifications

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Active Degrees-of-Freedom 3 (translational)
Workspace 300x300x200 mm3
(12x12x8 in3)
Maximum Force - continuous/peak 100 N (22.5 lbf) /
200 N (45 lbf)
Position Resolution 0.008 mm (0.00031 in)
Backdrive Friction 5 N (1.1 lbf)
Inertia - apparent at handgrip 3.0 kg
External Dimensions 685x685x788 mm3
 (27x27x31 in3)

 
Potential applications of Excalibur include virtual reality training, computer-aided design (CAD), telerobotic manipulation, and entertainment.  The compelling effect of haptic feedback is demonstrated in a virtual building block simulation shown below.  The user can pick and place different objects in a virtual assembly.  Force feedback enforces physical constraints, preventing the blocks from impeding on each other.

LHD Operational Instructions

Research Projects

Time Domain Passivity Control

Haptic Feedback of Manipulator Kinematic Conditioning for Teleoperation

Virtual Building Block Training Study

Publications (*)

(*) Note: Most of the BRL publications are available on-line in a PDF format. You may used the publication's reference number as a link to the individual manuscript.

[Th022]
R. J. Adams, 'Stable Haptic Interaction with Virtual Environments,' Ph.D. Thesis, University of Washington, Department of Electrical Engineering, September, 1999.