摘要
由于四驱轮毂电动汽车具有分布式四轮独立转向的能力,利用四轮独立转向控制策略改善汽车操纵稳定性,在汽车转向运行工况下采用前馈-反馈联合控制,其中前馈基于阿克曼转向定理,反馈基于模糊PID控制的联合控制方式。采用Carsim与Matlab/Simulink联合建立整车控制仿真模型,输入为左前轮转向角,其余3个车轮转向角满足阿克曼转向几何关系并输出,实现前馈控制;以横摆角速度理想值与实际值的偏差作为模糊PID控制器的输入,输出为3个车轮转角的修正系数,实现四轮独立转向的反馈控制。选取不同附着路面和车速条件,在角阶跃转向下进行仿真验证,对比4WIS的前馈-模糊反馈联合控制与前馈-模糊PID反馈联合控制的汽车操纵稳定性。仿真结果显示:所设计控制策略改善了车辆操纵稳定性。
With the help of four-wheel drive hub electric vehicle having the ability of distributed four-wheel independent steering,The four-wheel independent steering control strategy is used to improve the vehicle control stability,Feedforward-feedback joint control is used in steering operation,The feedforward adopts ackerman theorem and the feedback is based on fuzzy PID control joint control strategy. Carsim and Matlab/Simulink is used to establish a Joint Vehicle Simulation Control Model.The input of the vehicle system simulation is left front steering angle,and the remaining three wheel steering angles satisfy the Ackerman steering geometry and output to implement feedforward control;The deviation between the ideal value of yaw velocity and the actual value is taken as the input of fuzzy PID controller,and the output is the correction factor of the other three wheel steering angles so as to realize the feedback control of four-wheel independent steering. Different adhesion road surface and speed conditions are selected and verified by simulation under angular step steering. The control stability of the combined feed-forward fuzzy feedback control and feed-forward fuzzy PID control of 4 WIS was compared. The results showed that the design of the control strategy can effectively improve the vehicle handling stability.
引文
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