Improved Transparency in Bilateral Teleoperation with Variable Time Delay

Communication time delay has been a major barrier to achieving high performance while maintaining stability in bilateral teleoperation. Building upon the results of our recent work in [1], a provably stable adaptive controller is proposed for variable delay teleoperation. The controller utilizes a model of the system dynamics and the time delay within a predictive control framework to improve the response transparency. It can also adapt to uncertainties in the user and environment dynamics. The performance objectives are delay-free position tracking between the master and slave and the establishment of a virtual mass-damper tool impedance between the user and environment. Delay reduction is accomplished based on a state observer and estimates of the system parameters. Using the delay reduced dynamics, an adaptive output regulation problem is formulated and solved. A Lypunov-based analysis of the performance and stability of the resulting system is presented. Simulation results with a single-axis teleoperation setup demonstrate the effectiveness of the proposed approach.