Stability and performance in delayed bilateral teleoperation: Theory and experiments

In the presence of communication latency in a bilaterally controlled teleoperation system, stability and transparency are severely affected. In this paper, based on a passivity framework, admittance-type and hybrid-type delay-compensated communication channels, which warrant different bilateral control architectures, are introduced. Wave transforms and signal filtering are used to make the delayed-communication channel passive and passivity/stability conditions are derived based on the end-to-end model of the teleoperation system with and without incorporating force measurement data of the master and the slave manipulators' interactions with the operator and the remote environment in the control configuration. Based on analogies of the hybrid parameters of the teleoperation systems, it is demonstrated that using force sensor measurements about hand/master and/or slave/environment interactions in the control algorithm can significantly improve teleoperation transparency. Experimental results with a soft-tissue task for a hybrid-type architecture and for round-trip delays of 60 and 600 ms further substantiate the hypothesis that using slave-side force measurements considerably enhances the matching of the master and the slave forces and consequently the transparency compared to a position error-based configuration. (C) 2008 Elsevier Ltd. All rights reserved.