Telerobotics: Problems In Display, Control And Communication

An experimental telerobotics (TR) simulation is described suitable for studying human operator (H.O.) performance. Simple manipulator pick-and-place and tracking tasks allowed quantitative comparison of a number of calligraphic display viewing conditions. The Ames-Berkeley enhanced perspective display was utilized in conjunction with an experimental helmet mounted display system (HM0IFIt provided stereoscopic enhanced views. Two degree-of-freedom rotations of the head were measured with a Helmholtz coil instrument and these angles used to compute a directional conical window into a 3-D simulation. The vector elements within the window were then transformed by projective geometry calculations to an intermediate stereoscopic display, received by two video cameras and imaged onto the HID mini-display units (one-inch CRT video receivers) mounted on the helmet. An introduced communication delay was found to oroduce 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 seconds may relate to this robustness of H.0. control to delay. A number of control modes could be compared in this TR simulation, including displacement, rate iiracceleratory control using position and force joysticks. A homeomorphic controller turned out to be no better than joysticks; the adaptive properties of the H.O. can apparently permit quite good control over a variety of controller configurations and control modes. Training by optimal control example seemed helpful in preliminary experiments.