Stable Bilateral Teleoperation with Bounded Control

This paper studies a problem of bilateral teleoperation in the presence of asymmetric communication delays, in the case when there is a controller saturation constraint on both the local and remote manipulators. Stability under time delays has been a key challenge in the control of a teleoperation system, and several controllers, mostly based on the concept of passivity, have been proposed over the past two decades. The recently proposed controllers with damping injection improve tracking performance in addition to guaranteeing stability, due to explicit position information in the controller. These results are extended in the case of manipulators that can only produce bounded joint torques for coordination and force reflection. Sufficient conditions for guaranteeing stability and tracking are provided under such a controller restriction. The proposed scheme is validated by experiments on two three degrees of freedom manipulators.