无人车辆行驶路径的分层协调最优跟踪控制

Travelling Path Hierarchical Coordinated Optimal Tracking Control of Intelligent Vehicle

为了实现无人车辆对给定路径高精度跟踪控制,设计了分层协调最优控制器的路径跟踪方法。首先建立了车辆的动力学模型;综合路径跟踪控制精度和稳定性,以分段函数的形式设定了预瞄距离;建立了单点预瞄控制系统的状态空间方程并进行了线性化处理。设计了分层协调最优跟踪控制器,上层控制使用LQR最优控制,基于系统状态得到实时最优控制律;下层控制使用参数智能整定PID控制,实现了参数对系统工况的实时最优化,从而下层控制器能够准确跟踪上层控制器计算的最优控制律。经仿真验证,在变道-直线行驶和U形轨迹中,分层协调最优控制器的跟踪精度最高,且控制律幅值整体小于另外两种控制器。在连续转弯、大曲率等复杂道路的跟踪控制中,分层协调最优控制器能够实现较高精度跟踪,而文献[12]优化控制跟踪失败。实验结果表明,分层协调最优控制器具有较强跟踪能力和较好鲁棒性。

In order to realize the high-precision tracking control of unmanned vehicles on a given path,a path tracking method of hierarchical coordinated optimal controller is designed.Firstly,the dynamic model of the vehicle is established;Integrating the accuracy and stability of path tracking control,the preview distance is set in the form of piecewise function.The state space equa⁃tion of single point preview control system is established and linearized.The hierarchical coordinated optimal tracking controller is designed.The upper controller is designed by LQR optimal control,and the real-time optimal control law is obtained based on the system state.The lower controller is designed by the parameter intelligent tuning PID control to realize the real-time optimiza⁃tion of the parameters to the system working conditions,so that the optimal control law calculated by the upper controller can be accurately tracked by lower controller.The simulation results show that in Lane change-straight path and the U-shaped trajecto⁃ry tracking accuracy of the hierarchical coordinated optimal controller is the highest,and the amplitude of the control law is also less than the other two controllers as a whole.In the tracking control of complex roads such as continuous turning and large curva⁃ture,the hierarchical coordinated optimal controller can achieve high-precision tracking,but the optimal control tracking in lit⁃erature[12]failed.The experiment results show that the hierarchical coordinated optimal controller possess strong tracking ability and strong robustness.