汽车高速行驶时自动紧急转向避撞的前馈与反馈跟踪控制的研究

Research on Feedforward and Feedback Tracking Control for Automatic Emergency Steering Collision Avoidance in Vehicle High-speed Driving

通过建立汽车避撞质点模型,对3种不同避撞方式的有效性进行了对比分析。计算结果表明,车辆在高速紧急避撞时,转向避撞所需的纵向距离比制动避撞小,且与制动加转向联合避撞的结果较为接近。据此,设计了前馈与反馈相结合的自动转向避撞控制器。选取过渡较为平缓的七次多项式参考路径,结合线性2自由度转向动力学模型,从而得出前馈车轮转角。同时,以车辆实际路径相对参考路径的侧向位移偏差作为反馈,进行PID反馈控制器的设计。最后对所开发的控制器进行了仿真验证,结果表明,所设计的前馈与反馈跟踪控制器具有较好的实际跟踪效果、高鲁棒性和较强的抵御侧向风等外界干扰的能力,从而能实现有效避撞。

A particle model for vehicle collision avoidance is established to conduct a comparative analysis on the effectiveness of three different collision avoidance methods.The results show that during vehicle high-speed emergency collision avoidance,steering collision avoidance requires smaller longitudinal distance than braking collision avoidance does and is closer to that with combination of steering and braking collision avoidance.Based on this,an automatic steering collision avoidance controller combining feedforward and feedback is designed.By selecting seven-order polynomial reference path with smooth transition and combined with 2-DOF linear steering dynamics model,the feed-forward wheel turning angle can be obtained.In addition,PID feedback controller is designed with the lateral displacement deviation between actual path and reference path as feedbacks.Finally,a simulation verification is performed on the controller designed.The results show that the feedforward and feedback tracking controllers designed have good tracking effect in actual practice,high robustness and strong ability to resist side wind and other external disturbances,and hence can achieve effective collision avoidance.