Fault Tolerant Control of 4-Wheel Independent Drive Vehicle Subject to Actuator Faults Based on Feasible Region

Actuator fault will lead to the damage of vehicle driving ability. How to analyze the residual driving ability of the vehicle and use the residual driving ability to carry out targeted fault tolerance control (FTC) is the difficulty of FTC for automatic driving vehicles. In this article, an active FTC strategy for actuator fault of four wheels independent drive vehicles and a reference target reshaped scheme (RTRS) are proposed. The method consists of two parts. The first part calculates the limit of the vehicle's resultant longitudinal force, lateral force and yaw moment through the analysis of the friction limit between the tire and the ground and the vehicle's driving demand, which is called the driving capability feasible region (DCFR). Considering the impact of actuator fault on the tire force, the second analysis obtains the vehicle's residual driving limit, which is called the fault tolerant feasible region (FTFR). The upper Model Predictive Control (MPC) motion controller based on the FTFR and the lower allocation controller are designed to realize the FTC algorithm of the vehicle. The second part focuses on the fault scenes that can not be solved by a fault-tolerant controller alone. By weakening the driving task, priority is given to ensuring that the vehicle driving meets the driving capacity limit. The specific way is based on the optimization dynamic solution method, which comprehensively considers the FTC and the original reference target and uses the future output matrix equation of the upper MPC motion controller to design the optimization target to solve the feasible vehicle driving state, so as to achieve the RTRS. Carsim Simulink joint simulation is used to conduct FTC simulation of vehicle stability system actuator faults. The experimental results verify the effectiveness of the proposed FTC method and the RTRS to solve the problem of vehicle stability system actuator fault.