Globally Stable Output Feedback Synchronization of Teleoperation with Time-Varying Delays

TL;DR

This paper introduces a globally stable teleoperation control method that uses novel velocity observers to synchronize master and slave robots with time-varying delays, eliminating the need for velocity measurements.

Contribution

It proposes simplified augmented Immersion and Invariance velocity observers with dynamic scaling for improved convergence and stability in teleoperation systems with delays.

Findings

Observers achieve globally convergent velocity estimation.

Control strategy guarantees synchronization without velocity measurements.

Numerical results confirm stability and performance.

Abstract

This paper presents a globally stable teleoperation control strategy for systems with time-varying delays that eliminates the need for velocity measurements through novel augmented Immersion and Invariance velocity observers. The new observers simplify a recent constructive Immersion and Invariance velocity observer to achieve globally convergent velocity estimation with only $n+2$ states, where $n$ is the number of degrees of freedom of the master and slave robots. They introduce dynamic scaling factors to accelerate the speed of convergence of the velocity estimates and, thus, to limit the energy generated by the velocity estimation errors and to guarantee sufficient estimate-based damping injection to dissipate the energy generated by the time-varying delays. The paper shows that Proportional plus damping control with the simplified and augmented Immersion and Invariance-based velocity observers can synchronize the free master and slave motions in the presence of time-varying delays without using velocity measurements. Numerical results illustrate the estimation performance of the new observers and the stability of a simulated two degrees-of-freedom nonlinear teleoperation system with time-varying delays under the proposed output feedback Proportional plus damping control.