基于Hamilton理论的无人车路径跟踪控制

Path Following Control of Autonomous Vehicles Based on Hamilton Theory

针对当前车辆路径跟踪控制存在精度低、可靠性差的问题,基于Hamilton理论提出一种四轮驱动四轮转向无人车路径跟踪分层控制方法.通过集成车辆动力学模型和路径跟踪模型,建立了路径跟踪误差模型,结合系统控制目标,提出采用Hamilton理论设计车辆上层控制器,用于实现路径跟踪误差模型的镇定,从而提高车辆路径跟踪的精度与鲁棒性.同时,在下层控制器中,设计4个车轮纵向轮胎力分配算法,通过轮胎力的动态分配满足车辆上层控制需求.利用CarSim和Simulink搭建车辆路径跟踪联合仿真模型并进行仿真实验,仿真结果表明,提出的无人车路径跟踪分层控制策略能够通过前后轮转角以及4个轮胎力的实时控制与分配,抑制路径跟踪过程中的横向误差和航向误差,提高路径跟踪精度并确保控制系统的可靠性.

To solve the problems of low precision and poor reliability in the path following control of autonomous vehicles,a hierarchical path following control strategy was presented basis on Hamilton theory for four wheel independent drive and four wheel independent steering autonomous vehicles.Integrating vehicle dynamic model and path following model,an error model of path following was presented.According to the control target of path following system,the Hamilton theory was applied to design the upper layer vehicle controller,used to achieve the stabilization and convergence of path following error model and improve the accuracy and robustness of vehicle path following system.Moreover,in the lower layer controller,a distribution algorithm was designed for four-wheel longitudinal tire force to meet control demand of upper layer with dynamic orientated distribution of tire force.A simulation model for vehicle path following was established in CarSim and Simulink software and the simulation verification was carried out.The results show that the proposed hierarchical path following control strategy of autonomous vehicles can restrain the lateral offset and heading error during process of path following control,synchronously improve the accuracy of path following and ensure the reliability of path following control system by real-time control of front and rear wheel steering angle and distribution of four wheel tire forces.