The inertial force due to the acceleration of a locomotion interface is identified as a difference between virtual and real-world locomotion. To counter the inertial force, inertial-force feedback was implemented for the Treadport, a locomotion interface. A force controller was designed for a mechanical tether to apply the feedback force to the user. For the case of the user accelerating forward from rest, psychophysical ex periments showed that subjects preferred inertial-force feedback to a spring-feedback force proportional to position or to position control, where the force feedback maintained a force of zero on the subject.

Determination of human hand poses from hand master measurements of joint angles requires an accurate human hand model for each operator. A new method for human hand calibration is proposed, based on open-loop kinematic calibration. The parameters of a kinematic model of the human index finger are determined as an example. Singular value decomposition is used as a tool for analyzing the kinematic model and the identification process. It was found that accurate and reliable results are obtained only when the numerical condition is minimized through parameter scaling, model reduction and pose set selection. The identified kinematic parameters of the index finger with the Utah Dextrous Hand Master show that the kinematic model and the calibration procedure have an accuracy of about 2 mm.

This paper presents a design concept for a head-mounted display, incorporating color stereo vision using commercial LCDs and our own optical relay design. The focus here is on the optical system design, which must meet specifications for a wide field of view, size and cost constraints, and aberration minimization based on human factors. Two multispherical lens systems are presented and compared, one a straight structure and the other a folded structure, which satisfy the design constraints. Their aberrations (distortion, coma, lateral color, field curvature, and astigmatism) have been well corrected, according to human perceptual constraints explicitly discussed. Each has a 20-mm eye relief and an instantaneous field of view greater than 60°; the former has an exit pupil of 10 mm and the latter of 8 mm.

An optimized fingertip mapping (OFM) algorithm has been developed to transform human hand poses into robot hand poses. It has been implemented to teleoperate the Utah/MIT Dextrous Hand by a new hand master: the Utah Dextrous Hand Master. The keystone of the algorithm is the mapping of both the human fingertip positions and orientations to the robot fingers. Robot hand poses are generated by minimizing the errors between desired human fingertip positions and orientations and possible robot fingertip positions and orientations. Differences in the fingertip workspaces that arise from kinematic dissimilarities between the human and robot hands are accounted for by the use of a priority based mapping strategy. The OFM gives first priority to the human fingertip position goals and the second to orientation.