Nonsingular Fast Terminal Sliding Mode Fault-Tolerant Control Scheme for Four-Wheel-Independent-Drive Electric Vehicles with Fault Observer

For four-wheel-independent-drive electric vehicles (4WID-EVs), the increasing number of actuators and electronic components raises the risk of actuator failure for the vehicle, potentially threatening driving safety. When actuator faults occur, the faulty actuator introduces disturbances to the vehicle system that threaten vehicle stability. To solve this problem, a nonsingular fast terminal sliding mode fault-tolerant control (FTC) scheme is proposed for 4WID-EVs. Firstly, the vehicle dynamics model under fault conditions is established. Secondly, a nonsingular fast terminal sliding mode controller is designed to track the reference vehicle states. A sliding mode fault observer is designed to obtain the fault information of faulty actuators. In the lower layer, the torque distribution approach which considers physical limitation and road adhesion is proposed. Finally, comparative works are conducted through simulation. The results demonstrate that the proposed scheme can improve yaw rate tracking accuracy by 63.4% in simulation, compared with the classical sliding mode FTC scheme. The proposed scheme may serve as a theoretical reference for fault-tolerant control in 4WID-EVs.