极限工况下无人驾驶车辆稳定跟踪控制

Stable Tracking Control of Autonomous Vehicles at Extreme Conditions

针对无人驾驶车辆在极限工况下跟踪控制精度和稳定性均难以保障的问题,提出一种纵横向稳定性综合协调控制方法。首先对无人驾驶车辆在摩擦极限下的速度进行规划,通过纵向加速度前馈和状态反馈控制器实现极限车速下的速度跟随。其次将预瞄前馈与人工势场反馈相结合设计了横向路径跟踪控制器。提出了基于期望与实际横摆角速度偏差的稳定性控制策略,优化纵向控制的驱动力矩。Simulink/Carsim联合仿真结果表明,所提出的纵横向协调稳定控制方法可在极限工况下改善无人驾驶车辆瞬态响应,抑制道路曲率突变处的超调量,减少路径跟随中的稳态误差,提高了无人驾驶车辆的轨迹跟踪精度和弯道运动过程中的横向稳定性。

Aiming at the difficulty in ensuring the accuracy and stability of tracking control of autonomous vehicles under extreme conditions,a comprehensive coordinated control scheme for longitudinal and lateral stability is proposed.Firstly the speed of autonomous vehicle under friction limit is planned and the speed tracking under the limit speed is achieved by means of longitudinal acceleration feedforward and state feedback controller.Then a lateral path tracking controller is designed by combining preview feedforward with artificial potential field feedback,and a stability control strategy is proposed based on the deviation of actual yaw rate from desired one,and the driving torque of longitudinal control is optimized.The results of Simulink/Carsim co-simulation show that the proposed comprehensive control scheme for longitudinal and lateral stability can improve the transient response of autonomous vehicles under extreme conditions,restrain the overshoot at the sudden change of road curvature,reduce the steady-state error in path following,and enhance the trajectory tracking accuracy and the lateral stability in the course of curve movement of autonomous vehicles.