PERFORMANCE EVALUATION OF A 6-AXIS GENERALIZED FORCE-REFLECTING TELEOPERATOR

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 custom 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-in-hole insertion, electrical connectors, velcro attach-detach, and a twist-lock multipin connector. Each task was repeated three times under several operating conditions: "normal" bilateral telemanipulation, forward position control without force feedback, and shared control. In shared control, orientation was locally servo-controlled to comply with applied torques, while translation was under operator control. All performance measures improved as capability was added along a spectrum of capabilities ranging from pure position control through force-reflecting teleoperation and shared control. Performance was maximal for the bare-handed operator.