基于滚动优化的汽车换道动态轨迹规划和轨迹跟踪控制

Dynamic Trajectory Planning and Tracking Control of Vehicle Lane Changing Based on Rolling Optimization

针对传统换道控制算法难以有效应对前方车辆状态变化的问题,提出基于滚动优化的汽车换道动态轨迹规划方法,并设计轨迹跟踪控制器进行轨迹跟踪。首先,基于五次多项式设计换道参考轨迹方程,并建立换道轨迹评价指标确定换道时间。其次,构建换道动态轨迹规划函数,考虑相邻周期内所规划轨迹的偏差,设计滚动优化目标函数。建立跟随前车运动的危险包络椭圆约束来保证避撞安全性,同时考虑换稳定性约束和道路边界约束,将动态轨迹规划问题变为滚动优化问题,规划出可以适应前车状态变化的动态换道轨迹。然后,设计用于确定理想前轮转角的模型预测控制器来实现轨迹跟踪。最后,对所提出的方法进行仿真和硬件在环试验,仿真和试验结果表明,所提出的控制方法可以使车辆应对不同的换道环境,能够保证车辆的换道安全性和舒适性。

According to the shortcoming that the traditional lane change trajectory planning method is difficult to effectively deal with the changes of the movement state of the preceding vehicle,a dynamic trajectory planning method for vehicle lane change based on rolling optimization is proposed,and a trajectory tracking controller is designed to track desired trajectory.Firstly,the lane change reference trajectory equation is designed based on the fifth degree polynomial,and the lane change trajectory evaluation index is established to determine the lane change time.Secondly,the lane change dynamic trajectory planning function is constructed.Considering the deviation of the two planned trajectories in consecutive period,the optimal objective function is designed.The constraint of the dangerous envelope ellipse following the movement of the preceding vehicle is established to ensure collision avoidance safety.Considering the stability constraints and road boundary constraints,the dynamic trajectory planning problem is transformed into a rolling optimization problem to plan a dynamic lane change trajectory that can adapt to the changing vehicle in the state.Then,to obtain the desired front wheel steering angle,a model predictive controller is designed.Finally,simulations and hardware-in-the-loop tests of the proposed algorithm are carried out.The simulation and test results show that the proposed method can control the vehicle cope with different lane changing environments,and can ensure the safety and maintain the comfort of lane-changing.