Adaptive Control for Teleoperation System With Varying Time Delays and Input Saturation Constraints

This paper addresses the adaptive control of teleoperation system with actuator saturation. To unify the study of actuator saturation, passive/nonpassive external forces, asymmetric time-varying delays, and unknown dynamics in the same framework, a novel switched control scheme is developed, where a special switched filter is investigated. In the saturation scenario, the designed controller consists of a generalized controller and a nonlinear saturation function. By placing the nonlinear saturation function on the outside of the generalized controller, and further jointing with the design of switched filter, the designed generalized controller needs not consider the actuator saturation. Specifically, it is designed to be in the form of proportional plus damping injection plus switched filter. Then, the complete closed-loop system is modeled as a special switched system. It is finally established to be state-independent input-to-output stable, where the ultimate boundedness of the tracking error is ensured for any bounded exogenous forces, which is demonstrated by the experimental studies.