Direct Yaw Moment Control for Electric Vehicles with Variable-Rate-Slip-Ratio-Limiter Based Driving Force Control

Yaw-rate control by direct yaw moment control (DYC) for in-wheel motor electric vehicles has been studied for years. However, how to properly treat the difference between the wheels’ friction limit circles is still an open issue. For instance, in conventional methods, the yaw-rate might not follow the reference value due to the utilization of a fixed-slip-ratio-limiter regardless of the cornering operation. To deal with this problem, this paper proposes a new DYC method, which is based on driving force control with variable-rate-slip-ratio-limiter. To evaluate the effectiveness of the proposed method, simulation and experiment were conducted using a four-wheel vehicle under a low-friction surface condition. Experimental results show that, in comparison with the conventional method, the proposed method can reduce the root mean square deviation of the yaw-rate tracking error by 62.7%.