Fault-Tolerant Control Based on State Observer and Optimal Allocation for Four-Wheel Independent Drive Electric Vehicle

In this paper, the velocity tracking control problem and the lateral stability problem of the four-wheel independent drive electric vehicle (4WID-EV) system under actuator fault conditions are studied. Firstly, the 7 degrees of freedom (DOF) vehicle model and linear 2 DOF ideal vehicle model are constructed in this paper. Secondly, a nonlinear state observer is designed to track the real system states. Then, a double-layer controller is constructed to guarantee the longitudinal motion performance and lateral stability of the vehicle by updating the input voltage of the four in-wheel motors to control both the longitudinal driving force and the yaw moment, where the sliding mode control (SMC) and quadratic programming are used in the upper and lower controllers, respectively. Finally, the effectiveness of the method proposed is verified by three different maneuvers.