Globally Stable Output Feedback Synchronization of Teleoperation with Time-Varying Delays
For teleoperation systems with time-varying delays, this work provides a globally stable output feedback solution that removes the need for velocity sensors, addressing a practical bottleneck in implementation.
This paper presents a globally stable teleoperation control strategy for systems with time-varying delays that eliminates the need for velocity measurements using novel augmented Immersion and Invariance velocity observers. The approach achieves globally convergent velocity estimation with only n+2 states and demonstrates synchronization of master and slave motions without velocity measurements, validated through numerical simulations.
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.