Multi-Objective Optimal Based Fault Tolerant Control Allocation for Over-Actuated Electric Vehicles

The in-wheel-motor-driven electric vehicle is a typical over-actuated system and its chassis actuators have high flexibility. In order to give full play to the advantages of independent control of the four-wheel torque driven by the wheel hub motors, different control objectives are emphasized for various working conditions. In this paper, an improved two-step optimization method is proposed and a second-order sliding mode variable structure control is adopted to meet different requirements as vehicles under complex conditions, that is, to improve the energy efficiency, the stability, and the fault tolerance performance when the failure happens to the actuator suddenly. Co-simulation of CarSim and Simulink is carried out under specific driving condition to verify the performance of the proposed control methods. The result demonstrates that the proposed controller can reduce the energy consumption under normal steady driving conditions and guarantee the dynamic performance and fault-tolerant performance under extreme conditions such as the wheel fails to provide driving torque.