汽车自动驾驶的方向与车速控制算法设计

Design of Steering and Speed Control Algorithms for Automatic Driving of Automobiles

用于港口集装箱转运和路面疲劳试验加载等场合的半挂汽车列车运输具有线路固定和场地封闭等特点,采用自动驾驶将提高行车安全、减少人力成本。以半挂汽车列车为控制对象,设计了汽车自动驾驶的方向和车速控制算法。采用基于侧向位置偏差和航向偏差联合控制参数的方向控制策略。为增强方向控制算法对不同车速的适应性,引入基于稳态转向增益的方向控制增益调度。车速控制采用预瞄位置期望车速与当前实际车速的偏差反馈PID控制。以油门开度与制动踏板行程为非相容组合控制输入,依据期望纵向加速度确定不同控制输入方式的切换及控制输入大小。采用Matlab/Simulink和TruckSim协同仿真手段评价自动驾驶控制效果。仿真结果表明在设定不同路径和目标车速下,提出的算法均能以较小侧向位置偏差、航向偏差和车速误差实现路径和车速跟踪。

Automatic driving will improve traffic safety and reduce manpower costs of tractor semi-trailer transport used for port container transshipment and road fatigue test loading,et al,where the routines are fixed in closed premises.With tractor semi-trailers as a plant,automatic driving control algorithm including the steering and speed control is proposed.The steering control algorithm uses united control parameters of the vehicle＇s lateral position deviation and heading error and a gain scheduling method based on the steady steering gain is introduced to enhance the adaptability of the algorithm to various vehicle speeds.A PID controller is used for speed control,with the feedback of the difference between current vehicle speed and the desired one at the previewed location.Switching among different control input modes and the magnitude of control input are determined according to desired longitudinal acceleration,with the integrated accelerator/brake pedal travels as the non-compatible combined control inputs.Using the co-simulation approach based on Matlab/Simulink and TruckSim,effectiveness of the automatic driving is evaluated and simulation results show that under different path and target vehicle speed settings,the vehicle control by the proposed algorithm can track the desired path and speed with small lateral position deviation,heading error,and speed error.