三轴车辆全轮转向最优控制

Optimal Control of All-wheel Steering in Three-axle Vehicle

为提高三轴车辆在正常行驶工况下的操纵稳定性,综合考虑车辆的低速和高速转向性能,提出了三轴车辆全轮转向最优控制策略。建立了三轴全轮转向车辆的线性2自由度模型,分别制定了车辆低速和高速时的控制目标并建立了相应的理想模型,应用线性二次型最优控制中的状态调节器理论,采用前馈加状态反馈跟踪理想模型的控制方法设计了全轮转向最优控制系统,最后利用MATLAB/Simulink建立了控制系统仿真模型,对控制系统在不同车速下的控制性能进行了仿真。结果表明,全轮转向最优控制方法低速时可使车辆具有所在车速下的最小转弯半径,高速时在改善车辆稳定性的同时不增加驾驶员的操作负担。

For enhancing the handling stability of three-axle vehicles in normal driving conditions,an optimal control strategy for all-wheel steering of three-axle vehicles is proposed with a concurrent consideration of both low and high speed steering performances.A linear 2 DOF model for three-axle vehicle with all-wheel steering is built,the vehicle control objective for both low and high speeds is worked out respectively,and corresponding desired vehicle models are established.By applying the state regulator theory of linear quadratic optimal control and using a control technique of tracking desired models by feed-forward and state feedback,an optimal control system of all-wheel steering is designed.Finally,a simulation model for the control system is built with MATLAB/Simulink with its performance at different speeds simulated.The results show that the vehicle with optimal control of all-wheel steering can have the minimum steering radius at low speed,and can get a better stability at high speed with no further operational burden put on driver.