Piecewise integral-proportional wheel slip control for an in-wheel motor driven vehicle

Because the wheel torque of an in-wheel motor driven vehicle (IMDV) is controllable independently and has a quick motor response, vehicle dynamics control performance is excellent, especially in wheel slip control. In this paper, a novel wheel slip controller for based on torque vectoring control scheme IMDVs is proposed. The upper limit torque is regulated by slip control torque, which changes the effective operational range of the motor. Torque coordination is naturally executed by re-distribution, with no additional rules. Further, the piecewise integral-proportional control strategy for slip regulation is introduced to reduce dependence on model fidelity. The integral control mitigates the slip phenomenon quickly through withdrawing wheel torque step by step, and proportional control recovers the driving force with the wheel remaining in the stable region. These two stages are independent so that the control parameters can be tuned individually. A stability control analysis is also presented. Moreover, detached and split roads are chosen as simulation scenarios, with performance comparable to the traditional PI method, and real vehicle tests are performed to verify the effectiveness and feasibility of the proposed method.