Robust Adaptive Fault-Tolerant Control of Four-Wheel Independently Actuated Electric Vehicles

In this paper, the tracking control problem for four-wheel independently actuated (FWIA) electric vehicles (EVs) system with actuator fault and unmatched disturbance is investigated. An adaptive fast terminal sliding mode fault-tolerant control (AFTSMFTC) scheme is proposed. First of all, the FWIA electric vehicle (EV) system with actuator fault and unmatched disturbance model is established. Then, a novel composite observer is designed to estimate the state and disturbance of the EV system simultaneously; by introducing an updating law, the fault efficiency factor is reconstructed. Furthermore, in accordance with the estimated information, an AFTSMFTC strategy is proposed based on the tracking error and its derivative information. In the AFTSMFTC scheme, on one hand, two adaptive expressions are contained to realize a self-adapting adjustment to the controller parameters, such that a faster convergence can be guaranteed; on the other hand, the estimated disturbance value is utilized to design the scheme in order to improve the robustness of the tracking performance. Finally, three cases are given to illustrate the effectiveness of the proposed method.