基于多目标SMC汽车转向稳定性研究

Research on Vehicle Steering Stability Based on Multi-Objective SMC

为提高汽车转向稳定性,针对主动前转向(AFS)系统提出了一种基于可变传动比转向系统(VGRS)的多目标滑模控制(SMC)策略。首先依据AFS系统工作原理,建立了VGRS执行器数学模型,构建了控制器输出转向角与实际前轮转向角之间的关系。然后以双自由度汽车控制模型为基础,运用滑模变结构控制原理,设计了以侧滑角和偏航率为控制变量的滑模控制器,分析了该控制系统的稳定性。最后利用MATLAB和Simulink软件,在仿真平台上分别进行开环和闭环转向稳定性控制的仿真试验,结果表明,与模糊PID策略相比,SMC策略中的侧滑角和偏航率均有所降低,表明SMC策略能有效提高汽车转向稳定性。

In order to improve the vehicle stability,a multi-objective Sliding Mode Control(SMC)strategy based on Variable Gear Ratio Steering system(VGRS)was proposed for the Active Forward Steering(AFS)system.Firstly,the mathematical model of VGRS actuator was established according to the working principle of AFS system,then the relationship between the output steering angle of the controller and the actual front wheel steering angle was constructed.Then,on the basis of double degree of freedom motor control model,the sliding mode controller was designed using the principle of sliding mode variable structure control,with sideslip angle and yaw rate as control variable,and the stability of the control system was analyzed.Finally,using MATLAB and Simulink,simulation test of open loop and closed loop steering stability control was performed respectively on the simulation platform.The results show that the sideslip angle and yaw rate are reduced in SMC strategy compared with fuzzy PID,indicating that SMC strategy can effectively improve the stability of vehicle steering.