制动过程的主动转向干预控制

主动转向(AFS)能够提高车辆的转向跟随性和车辆的稳定性能,同时还能够产生额外的侧向力,抵御制动过程中由于制动力的不对称分配所引起的横摆及侧倾。首先基于主动转向的机构及制动过程建立了转向模型及车辆模型,并在该模型控制的设计中,利用横摆角速度和侧偏角反馈提高车辆的稳定性。同时,为了得到最佳的输出反馈增益矩阵,采用线性0]二次型调节器(LQR-line quadratic regulator)进行最优控制。通过制动过程中主动转向的干预作用的MATLAB仿真,以及没有转向干预控制的制动过程试验与仿真的对比,表明主动转向无需驾驶员的额外干预,通过电机的主动补偿提高车辆的侧向稳定性,同时还能够影响车辆的纵向动力学过程,缩短制动的有效距离。

Active Front Steering Intervention Control During Braking

Active front steering (AFS) can improve vehicle lane following, lateral stability, and additional lateral forces can be created to reject yaw and roll disturbances rise from braking. A simplified model of the steering system incorporates vehicle dynamics was analyzed based on the structure of AFS, and then the assisted motor angle was controlled by the feedback of both the yaw rate and the sideslip angle to improve vehicle stability in the controller. To get the optimum feedback gain of the control, an LQR (Line Quadratic Regulator) was used. And the intervention control of AFS during braking was simulated in MATLAB, and it was compared with the simulation and experiment of vehicle without AFS control. The results show that AFS intervention can not only improve vehicle lateral stability during braking process but also improve vehicle deceleration and reduce the braking distance.