Active safety control for distributed drive electric vehicle with unilateral motor fault based on mechanical redundancy

Abstract

Distributed drive can significantly improve the dynamics performance of electric vehicles. However, once the drive motor fails, it will cause harm to passengers and the surrounding environment. To solve the above problems, an active safety control method is proposed based on the mechanical redundancy of a centralized and distributed coupling transmission, which can switch the vehicle drive mode from two motors distributed drive to one motor centralized drive. Regarding fault diagnosis, a motor torque observer is established based on the coupling relationship between the steering system and the drive system to address motor communication faults. To reduce the risk of misdiagnosis, a combined fault diagnosis strategy that considers both torque difference and torque change rate is proposed. The effectiveness of the method is proved by simulation and real vehicle tests. In the aspect of safety control, a fast mode switching method from the distributed drive to the centralized drive is proposed. The test results show that the shift time of the fast mode switching method is reduced by 13 % compared with the traditional switching method, which can reduce the time of power interruption and quickly restore the driving force to ensure the vehicle safety.