Stability of delayed passivity-based teleoperation systems in transition

Abstract

Many robotics researchers have focused on stability in free and constrained motions, but only a few of them have considered system stability in the transition between these phases. For a teleoperation system, due to delay effects, studying this concept is even more crucial. Recently, passivity-based controller stability has been studied in free motion and constrained mode of a teleoperation system in the presence of constant time delay. However, the controller does not guarantee arbitrary switching between these modes. In this paper, a hybrid system theorem was employed to treat delayed teleoperative tasks that involve phase transition or switching. Applying this theorem, the stability of passivity-based architecture in transition was studied. It was proved that this type of controller is stable even with arbitrary switching. Experiments on a two-degrees-of-freedom nonlinear teleoperation system were conducted to verify the approach. Experimental results have shown that passivity-based architecture, as expected in controller design, is well suited for delayed teleoperation in transition. Moreover, even without force sensing, the system’s force tracking in dealing with a hard environment is admissible.