自主车辆安全系数估计与T形路口避碰规划

针对自主车辆T形路口协作问题，通过测量车辆速度和预碰点距离，提出安全系数估计方法，结合人工势场基本思想，实现车辆路口避碰，提高路口协作效率.首先以计算得到的安全系数为依据，评价驶入T形路口两辆自主车各自的安全程度，并利用人工势场产生的推拉作用估计协作自主车辆的期望控制力和速度.然后将估计的期望车速与反馈的实际车速形成偏差，利用增量型数字PI控制器实现自主车纵向车速的准确控制.最后以一定的策略完成两辆自主车的并线协作.仿真结果验证了基于安全系数估计的自主车辆T形路口协作避碰的可行性与有效性.

Estimation of the safety coefficient of autonomous vehicles and collision avoidance planning at the T-shape intersection

Focusing on the collaboration of autonomous vehicles at a T-shape intersection, by measuring the vehicle speed and the distance of the vehicle away from the preset collision point, a safety coefficient estimation method is proposed. In combination with the basic thoughts on the artificial potential field, the collision avoidance of vehicles at an intersection may be realized and the intersection collaboration efficiency may be improved. Firstly, based on the safety coefficient obtained by calculations, the safety degree of two autonomous vehicles driving into the T-shape intersection are evaluated respectively, the push-pull function is derived from the artificial potential field and is utilized to estimate the expected control force and speed of the autonomous vehicles; then, a deviation is formed between the estimated expected vehicle speed and the actual feedback speed, the increment-type digital PI controller is utilized to realize accurate control for the longitudinal speed of an autonomous vehicle; finally, proper tactics are applied to complete the parallel collaboration of the two vehicles. The simulation result verifies the feasibility and effectiveness of the cooperative collision avoidance of autonomous vehicles at a T-shape intersection estimated on the basis of the safety coefficient.