队列车辆碰撞严重性及车队排布策略

Vehicle Collision Severity and Configuration Strategy of Platoons

针对自动驾驶车辆队列发生不可避免碰撞的事故场景,研究以整体碰撞严重性达到最低为目标的车队排布策略。首先根据引发事故的障碍物是否会明显影响领航车运动,将碰撞划分为队内碰撞和队外碰撞。队列几何构型一定时,针对均质化队列发生一维碰撞过程建立理论模型,计入碰撞前车辆对前车紧急制动的感应及自车进行紧急制动的过程,计算并定义时间截断现象,据此将队列速度划分为低速、中速和高速,分析不同速度下,均质化队列中车辆长度、质量以及队列规模对车辆碰撞严重性影响。进一步,假定均质化队列中仅存在1辆异质车,即1辆大质量车或1辆紧急转向出队列的车辆,分析在不同速度下将异质车置于队列不同位置时对队列碰撞严重性的影响,最后通过PC-Crash仿真对结果进行验证。研究结果表明:在发生队内碰撞情况下,车辆质量与长度对车辆碰撞严重性无影响,队列速度越高碰撞严重性越大,但速度高于一定值后,碰撞严重性达到饱和状态,不随速度增加而增加;低速且所有车辆均参与碰撞时,将大质量车置于队列的前中部可使整体碰撞严重性最低,选择队列正中间位置车辆转向出队列可使整体碰撞严重性最低;高速时将大质量车置于队列中间位置能够最小化队列碰撞损伤,选择首、尾车辆转向出队列可使整体碰撞严重性最低;发生队外碰撞时,障碍车辆的速度、质量、长度均对碰撞严重性有影响,且队列速度越高碰撞严重性越大;低速时,将大质量车作为队列领航车能够最小化整体碰撞严重性,选择队列前中部的车辆转向出队列能够降低队列碰撞严重性;高速时,相比低速情况大质量车应适当后移,置于队列前中部能最小化队列碰撞严重性,选择首、尾车辆转向出队列可使碰撞严重性最低。研究结果对未来自动驾驶车辆队列行驶时队列车辆的排布策略具有一定指导作用。

In this study,platoon configuration strategies were developed to minimize the overall collision severity in unavoidable collision accidents of self-driving vehicle platoons.First,according to whether the obstacle-leader collision significantly affects the leader’s motion,the collision was divided into intra-platoon and extra-platoon collisions.Based on a specific platoon geometric configuration,a theoretical model for the one-dimensional collision of a homogenous vehicle platoon was established.The model reflected the vehicle perception and emergency braking process before the collision,and the time truncation was defined,according to which the platoon speeds were divided into low,medium,and high speeds.The effects of the vehicle length,vehicle mass,and platoon size on homogenous platoon collision severity at different speeds were analyzed.Further analysis assumed that under different speeds,only one heterogeneous vehicle,i.e.,a heavy or an emergency steering vehicle,was in the platoon,and the influence of the positions of the heterogeneous vehicles on the collision severity was determined.Finally,the results were verified through PC-Crash simulations.During intra-platoon collision,the vehicle mass and length do not influence vehicle collision severity.Within a specific speed range,the higher the platoon speed,the more significant the overall collision severity.However,when the speed exceeds a particular value,the severity reaches saturation,that is,the collision severity no longer worsens with speed.At low speeds,the overall collision severity is minimal when the heavy vehicle is in the middle front of the platoon and when the middle vehicle is steering out.At high speeds,the collision damage is minimized when the heavy vehicle is in the middle of the platoon,and the leader or the last vehicle steering can also minimize the overall collision severity.In extra-platoon collision,the speed,mass,and length of the obstacle vehicle influence the collision severity.The higher the platoon speed,the greater the collision severity.At low speeds,using the heavy vehicle as the leader can minimize the overall collision severity,and selecting the vehicle in the middle front for steering can also reduce platoon collision severity.At high speeds,the best position for the heavy vehicle moves backward compared to those at low speeds.The leader or the last vehicle steering can reduce the overall collision severity.This study will help analyze the vehicle configuration strategy of self-driving vehicle platoons in the future.