AUTOMOTIVE YAW RATE COORDINATED CONTROL IN ADVANCE UNDER URGENT STEERING CONDITION BASED ON ACTIVE FRONT STEERING AND DIFFERENTIAL BRAKING

摘要

Under urgent steering condition, the lateral force of automotive tire will easy reach saturation state, and result in steering out of control and yaw rate deviating from expectations. Differential braking control will lead to step change of yaw rate which is the disadvantage of driving. According to urgent steering condition, applying urgent steering intention identification and control in advance, the automotive yaw rate coordinated control in advance method is researched based on active front steering and differential braking. Aiming at yaw motion and lateral motion, the 2-DOF (2-degree of freedom) automotive steering dynamic model and tire model are established, the automotive steering saturation angle is calculated, and the urgent steering intention identification model is built. Using hierarchical control strategy, the automotive yaw rate coordinated control process based on active front steering and differential braking is proposed. Based on urgent steering intention identification, automotive information processing and yaw rate allocation control, the coordinated controller model is put forward. According to urgent double lane shift road condition and large curve obstacle avoidance condition, the control performance under urgent steering condition is analysed.