变曲率弯路车辆换道虚拟轨迹模型

Virtual trajectory model for lane changing of a vehicle on curved road with variable curvature

研究自动化公路系统车辆换道虚拟轨迹规划方法,建立基于奇次多项式的变曲率弯路换道轨迹模型.假设车辆起始车道和目标车道具有相同的瞬时中心,把车辆在弯曲路段换道时的运动分解为向道路瞬心的直线运动和绕道路瞬心的圆周转动.假设向心运动位移和转动角位移满足奇次多项式约束,由换道时间、位置要求以及车辆在换道开始时刻和结束时刻的期望状态确定两种运动满足的边界条件,利用边界条件确定多项式系数.根据向心运动位移和转动角位移多项式模型,建立换道虚拟轨迹数学模型.与现有弯路换道轨迹规划方法相比,取消道路曲率为常数的假定,得到的换道轨迹模型更具一般性.仿真结果验证了文中提出的变曲率弯路换到轨迹规划方法的可行性.

In this paper, a virtual trajectory planning method for vehicle lane changing in automated highway system is studied, and a trajectory model for lane changing on variable curvature road is established with odd-order polynomial constraints. Assuming that the starting lane and the target lane have the same instantaneous center, the motion for lane changing of vehicle on the curved road can be decomposed into a linear centripetal motion and a circular motion around the instantaneous centre of the curved road. If the centripetal motion displacement and the rotational angular displacement meet the requirement of odd-order polynomial constraints, the boundary condition of the above two kinds of motion may be obtained from the constraints, such as time, location, and desired state of vehicle at the start and end of the lane changing behavior. By applying the boundary conditions, the polynomial coefficient is deduced, and the mathematical model of virtual trajectory for lane changing can be designed based on the polynomial models of centripetal displacement and angular displacement. Compared with the existing trajectory planning method for lane changing on curved road, the curvature change has been taken into consideration, and the trajectory model for lane changing has been generalized. Simulation results verify the feasibility of the trajectory planning method proposed in this paper for lane changing on a curved road with variable curvature.