Fault-tolerant control of eight in-wheel-driving autonomous vehicle

In-wheel motor driving is regarded as an important development direction of vehicles. In-wheel motors design simplifies the chassis structure, but the increase in the number of actuators brings challenges to vehicle safety. Considering the faults of one or more actuators during path tracking working mode, a hierarchical fault-tolerant controller strategy for an eight in-wheel-driving autonomous vehicle with rear-wheel-steering (SWD-RWS) is proposed in this paper. The controller can be divided into two layers. The upper controller mainly includes the path tracking module and velocity planning control module, which receives desired path and then converts it into the longitudinal traction force and the yaw moment, receives maximum velocity and then generates velocity distribution among waypoints, respectively. The lower controller optimizes the allocation of vehicle-level forces and moments to the available in-wheel motors to achieve fault tolerance. A nonlinear vehicle dynamics model with 21 degrees of freedom (DOF) is established and simulated in Matlab/Simulink. Simulation results show that the proposed fault-tolerant control strategy can realize wheel torque redistribution when the in-wheel motor faults. Vehicle motion path tracking is not greatly affected, and the stability can be guaranteed.