Robust Adaptive Observer-Based Predictive Control for a Non-Linear Delayed Bilateral Teleoperation System

Abstract

In this paper, a new robust adaptive nonlinear teleoperation system using an improved extended active observer (IEAOB), adaptive Smith predictor (ASP) and sliding mode control is developed to address the time delay in the communication channels and the nonlinear robot model uncertainties. Firstly, an ASP based on Padé approximation and active observer is designed to compensate for the time delay effect. Specifically, the total network time delay is modelled by Padé approximation, and then an active observer is deployed to estimate the time delay. To ensure the time-varying delay effect is completely suppressed, a sliding mode control algorithm is further developed. Meanwhile, the IEAOB is utilized at both the master and slave sides to deal with the nonlinear model uncertainties, it can provide an accurate robot inertial parameters and friction estimation as well as external force estimation without a structured force model in the presence of disturbances. Finally, the stability of the designed teleoperation system is theoretically studied and the system effectiveness is demonstrated by applying it to a pair of Phantom Omni haptic devices connected via a communication channel with time-varying delays.