Nonlinear disturbance observer-based fault-tolerant control for flexible teleoperation systems with actuator constraints and varying time delay

Abstract

In this paper, designing a control law for teleoperation systems with flexible-link slave robots in the presence of dynamic uncertainties, disturbances, actuator faults and actuator constraints with time-varying communication delays is addressed. This study proposes a simple anti-saturation nonlinear fault-tolerant controller incorporating a disturbance observer. The attractive features of the proposed controller include the ability to cope with disturbances, avoiding actuators exceeding their usual bounds, and compensating for the actuator faults. Besides which, the controller has a simple structure, does not need a fault detection mechanism, and coordinates the master’s motion speed with the slave’s actuator. A Lyapunov–Krasovskii functional is used to prove the stability and tracking performance of the teleoperation system. The feasibility and efficiency of the proposed controller are corroborated through simulation results.