An adaptive controller for bilateral teleoperation under time delay

Previous efforts in bilateral time-delay teleoperation have mainly yielded control algorithms that sacrifice performance in order to guarantee robust stability. This paper proposes a provably stable adaptive predictive controller for teleoperation systems with communication delay. The method uses the model and delay information and can adapt to uncertainties in user and environment dynamics in order to achieve delay-free transparency objectives. These include position tracking and tool impedance shaping. Delay reduction is accomplished using a state observer and estimates of the system parameters. Teleoperation transparency objectives are attained within an output regulation control framework based on the predicted system dynamics. A Lyapunov analysis has been used to prove the stability of the system and to obtain the parameter adaptation law. Simulation results with a single-axis teleoperation setup demonstrate the effectiveness of the proposed approach.