Space teleoperation through time delay: review and prognosis

A 30-year history of research on dealing with the effects of time delay in the control loop on human teleoperation in space is reviewed. Experiments on the effects of delay on human performance are discussed, along with demonstrations of predictive displays to help the human overcome the delay. Supervisory control is shown to offer a variety of options, from switching to local impedance control upon contact with the environment to higher-level local automation. Wave transformation techniques to ameliorate the effects of delay are also described. Space teleoperations have tended to deal with the problem of time delay by avoiding it and not attempting to teleoperate from the ground. It is suggested that the US space effort might have gotten further ahead and at a lower cost with a greater is commitment to space teleoperation from the ground through the delay. Predictive display works well for free positioning. Local impedance control is recommended for control in contact with the environment, possibly accompanied by wave transformation techniques. Higher level supervisory control is always an option for sufficiently predictable tasks and will continue to improve with better sensors and task models