视线遮挡条件下面向弱势道路使用者的避撞策略研究

由于视线障碍物造成的“鬼探头”事故已经成为当前城市道路交通事故的主要类型之一。针对汽车碰撞视线遮挡条件下横穿的弱势道路使用者(VRU)的场景, 设计了1种基于碰撞时间比和安全制动距离的避撞策略, 建立车辆与VRU的交通状态数学模型, 分析“鬼探头”场景下的制动避撞临界距离。结合临界距离和车辆与VRU的碰撞时间比, 将可以避免碰撞的场景分为3种工况, 分别采用不同的制动减速度, 建立自动紧急制动避撞策略。通过Euro NCAP CPNC测试场景对该策略与传统TTC制动算法进行比较分析。结果表明, 在Euro NCAP CPNC测试场景中, 自车利用该避撞策略在理想情况下能够在更高的车速情况下完成避撞; 在不能避免碰撞的高速行驶工况中较传统TTC算法能够更加有效降低碰撞速度, 同时降低事故重伤风险和死亡风险, 提高车辆的安全性。 

A Study on Collision Avoidance Strategy for Vulnerable Road Users Under Visual Obstruction

The traffic accident caused by visual obstruction is one of the main types of current urban-road traffic accidents. The work proposes an autonomous emergency-brake avoidance control strategy based on the collision time ratio and the safe braking distance, aiming at the crossroad traffic accident caused by a visual obstruction between vehicle and vulnerable road users(VRU). Firstly, the traffic state model of the vehicle and VRU is established to analyze the critical distance of braking to avoid a collision. Then the collision avoidance scenarios are divided into three types with different braking deceleration speeds adopted. The autonomous emergency collision-avoidance control strategy is proposed based on the critical distance and the collision time ratio between the vehicle and VRU in this scenario. Finally, the strategy and the traditional TTC braking algorithm are analyzed by the Euro NCAP test scenario. The results show that the vehicle can avoid collisions at a higher speed under ideal circumstances using this strategy in the Euro NCAP CPNC test scenario. Compared with the traditional TTC algorithm, it can reduce the collision speed more effectively in the high-speed driving condition where collisions cannot be avoided and reduce the risk of serious injury and death to improve the safety of vehicles.