Abstract:

Distributed drive electric vehicles with independently controllable torque for each wheel hub motor represent a typical over-actuated system. By optimizing the distribution of driving torque among the wheels， fault-tolerant control can be achieved. Taking distributed drive electric vehicles as the research object and focusing on the trajectory-tracking problem in the presence of simultaneous failure of the steer-by-wire system and multiple actuators of the wheel hub motors， a fault-tolerant control method based on differential steering and torque allocation is proposed in this paper. The method employs a hierarchical architecture. In the upper-level controller， the desired front-wheel steering angle is obtained using a model predictive control method. When failure occurs in the steering system actuators， a sliding mode control method is utilized to calculate the differential steering torque. In the lower-level controller， the torque optimization allocation strategy for failed drive motors is determined based on quadratic programming algorithms， taking into account of fault diagnosis information. Finally， simulation experiments are conducted to evaluate the effectiveness of the proposed fault-tolerant control method under both single actuator failure and multiple actuators failure scenarios. The results validate the effectiveness of the proposed approach.

Key words: distributed drive electric vehicles, fault-tolerant control, trajectory tracking