Disturbance Observer and Fault Estimator-Based Tracking Control of Wheeled Mobile Robot

This paper proposes the robust and accurate sliding mode tracking control problem of wheeled mobile robot (WMR) systems with uncertain disturbances and actuator faults. In the first part, an adaptive disturbance observer (ADOB) is designed to handle the uncertainties of the disturbance, without requiring any assumptions about disturbance boundary information. In the second part, a fault estimator is designed to estimate the actuator fault using the Lyapunov stability theory. It is presented that when ADOB and fault estimator-based SMC are applied, then the robustness and the tracking performance improve. This novel sliding mode tracking controller is robust toward uncertainty and fault, and reduces chattering. Experiments demonstrate the advantages of tracking control performance and system robustness.