基于自适应预瞄路径的自动驾驶车辆寻迹和避障控制

Tracking and Collision Avoidance of Autonomous Vehicle Based on Adaptive Preview Path

  • 摘要: 寻迹控制作为自动驾驶车辆横向控制中最基本环节,其稳定性和跟踪精度通常与车速、转弯曲率等相关,直接影响车辆在复杂行驶工况中的安全性。为提高自动驾驶车辆在复杂工况下的稳定性和跟踪精度,结合路径规划、寻迹控制并考虑车辆稳定性提出基于自适应预瞄路径的自动驾驶车辆寻迹和避障控制方法。首先,基于车辆二自由度模型设计出预瞄距离自适应算法,其根据车辆动力学状态和路面附着调节预瞄距离;其次,通过三次多项式拟合方法给出给定预瞄距离下的预瞄路径;最后,基于避障能力、跟踪精度、车辆稳定性指标设计出粒子群优化算法(PSO),实现了算法参数的寻优。通过硬件在环试验和实车试验验证了算法在寻迹、换道和避障工况下效果,结果表明算法以小运算量实现了跟踪时的预瞄路径自适应调节,兼顾跟踪精度和车辆稳定性。

     

    Abstract: Path Tracking plays important role in the lateral control of autonomous vehicles. The stability and tracking accuracy are usually related to vehicle speed, road curvature, etc., which directly affect the safety in complex driving conditions. To improve the stability and tracking accuracy under complex conditions, path planning, tracking control and stability control are combined together to design a tracking control method based on adaptive preview paths. First, based on the vehicle's two-degree-of-freedom model, a preview distance adaptive algorithm is designed, which adjusts the preview distance according to the vehicle dynamics state and road adhesion. Secondly, the preview path at the desired preview distance is given by a cubic polynomial fitting method. Finally, based on performance of obstacle avoidance, tracking accuracy, and vehicle stability, a particle swarm optimization algorithm(PSO) is designed to optimize the algorithm parameters. The performances in path tracking, lane changing and obstacle avoidance conditions are verified in the hardware-in-the-loop tests and vehicle tests. The results show that the algorithm can adaptively adjust the preview path during tracking with low computation burden, and achieve the balance of tracking accuracy and vehicle stability.

     

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