基于Frenet坐标系的换道轨迹规划及跟踪验证

Research on Planning and Tracking of Lane-changing Trajectory Based on Frenet Coordinate System

为解决高速公路环境下的车辆自动变道问题,采用Frenet坐标系下的五次多项式算法对不同工况设计规划轨迹,实现自动变道辅助。首先根据自车状态与周围车辆状态预计变道所需直线距离,并在一定范围内进行多次五次多项式轨迹规划,得到备选轨迹集。以加速度最小为优化目标,对备选轨迹集中的所有轨迹进行评价,得到最佳换道轨迹。使用CarSim进行车辆和道路建模,在Matlab/Simulink中进行轨迹规划,并使用动力学模型的模型预测控制进行轨迹跟踪,验证了换道辅助系统的有效性。

To solve the problem of automatic lane changing of vehicles in the expressway environment,the fifth-order polynomial algorithm in the Frenet coordinate system is used to design and plan the trajectory according to different working conditions.First,estimate the straight-line distance required for lane change according to the state of the vehicle and surrounding vehicles,and perform fifth-order polynomial trajectory planning multiple times within a certain range to obtain candidate trajectories.Finally,with the minimum jerk as the optimization objective,all trajectories in the candidate trajectory set are evaluated to obtain the optimal lane change trajectory.CarSim is used for vehicle and road modeling,trajectory planning in Matlab/Simulink,and model predictive control of dynamic models is used for trajectory tracking,which verifies the effectiveness of the lane-changing assistant system.