Switching robust control for bilateral teleoperation

The inherent transparency-stability tradeoff in bilateral teleoperation poses a challenge to design controllers that find a proper balance between both requirements. Furthermore, when the environment of the teleoperation system varies within a large range, a single controller might not be sufficient to achieve both stability and high performance. In this paper, we propose the synthesis of a switching robust controller that allows to design multiple robust controllers suitable for different ranges of environment stiffness, so that an overall better performance is achieved. The controllers are scheduled using an estimate of the environment stiffness. During the design, we account for smooth switching among controllers and for the fact that environment estimators will have limited accuracy and uncertainty. We present synthesis, simulation, and experimental results of the proposed approach, thus showing the effectiveness of the method to improve the robust performance of the teleoperated system