考虑多性能约束的车辆主动前轮转向静态输出反馈控制

Static Output Feedback Control of Vehicle Active Front Steering Considering Multiple Performance Constraints

为使车辆能精确地跟踪理想横摆角速度,从而提高车辆路径跟踪能力,提出考虑多性能约束的主动前轮转向静态输出反馈(SOF)控制方法.由于行驶中车辆轮胎的侧偏刚度是一强非线性参数,所以将侧偏刚度作为模型的不确定性参数.基于饱和线性轮胎模型,建立二自由度车辆动力学多胞型模型来对参数不确定性进行处理.针对该类不确定性系统,考虑具有区域极点配置约束与H_(∞)性能约束的鲁棒SOF控制器设计问题.给出了该类不确定系统的线性矩阵不等式(LMI)充分条件,并首次扩展运用一种坐标转换矩阵优化方法来迭代求解所得到的LMI条件,从而得到该类不确定性系统的鲁棒最优H_(∞)SOF控制器.MATLAB/Simulink和CarSim的联合仿真结果表明,所设计的SOF控制器可显著提高对期望横摆角速度的跟踪性能,改善车辆路径跟踪能力,且对模型参数的不确定性具有良好的鲁棒性.

To enable the vehicle to accurately track the ideal yaw rate,thereby improving the vehicle path tracking ability,this paper proposes a static output feedback(SOF)control method for active front steering(AFS)considering multiple performance constraints.Since the cornering stiffness of vehicle tire is a strong nonlinear parameter,the cornering stiffness is taken as the uncertainty parameter of the model.In addition,the two-degree-of-freedom poly-topic model of the vehicle dynamics is established based on the saturated linear tire model to deal with the parameter uncertainty.Moreover,the design of robust SOF controllers with regional pole configuration constraints and H_(∞) performance constraints are considered for this type of uncertain system.Furthermore,the linear matrix inequality(LMI)sufficient conditions for this type of uncertain system are given,and a coordinate transformation matrix(CTM)optimization method is used to iteratively solve the obtained LMI conditions for the first time.Thus,the robust optimal H_(∞) SOF controller for this type of uncertain system is obtained.Co-simulation results of MATLAB/Simulink and CarSim show that the designed SOF controller can significantly improve the tracking performance of the desired yaw rate and improve the vehicle path tracking ability.In addition,the controller has a good robustness to the uncertainties of vehicle model parameters.