侧风干扰工况电动汽车EPS反向助力控制及试验

Reverse assistance control and tests of electric vehicle EPS system under anti-wind interference condition

针对侧风干扰特殊工况下汽车产生沿侧向风作用方向的偏移,导致方向盘被动产生与车轮同向的偏转,影响汽车稳定性的问题,建立了EPS系统动力学模型和侧向风干扰下整车二自由度模型,设计了一种反向助力策略和柔性PID控制方法,在驾驶员无输入情况下实现反向助力控制,避免汽车过度偏驶。基于高速水流模拟侧风设计实车试验系统,结果表明:反向助力控制下,汽车中轴线到参考基准的平均侧向位移比正向助力控制和无助力控制时分别减小了176%和70%;在40 km/h试验时,反助力控制的横摆角速度、侧向加速度的峰值与平均值比无助力控制时降低了28%～32%,侧向位移减小了41%;显著改善了汽车的稳定姿态,获得了更好的操纵稳定性。

The offset along the anti-wind direction is caused under anti-wind interference condition.And the steering wheel being passively deflected to the same direction of wheel influences the vehicle stability.The electric power steering（EPS）dynamic model and full-vehicle two degree-of-freedom（DOF） model with the lateral wind interference were established.The reverse assistance strategy and flexible-PID control method were designed.The reverse assistance control was adopted to avoid excessive side driving with no driver input.The real vehicle test system was designed by simulating crosswind with high-speed flow.The results show that the average lateral displacement of the reference base to vehicle axis were respectively reduced by 176% and 70% than the forward assistance control and no assistance control.Under 40 km/h condition,the peak and average value of yaw rate and lateral acceleration were reduced by 28%～32% and the lateral displacement was reduced by 41% compared with no control condition.The stability attitude was significantly improved and showed better handling and stability performance