面向快速路交通瓶颈的混合交通群体节流控制策略

Mixed traffic group throttling control strategy for traffic bottleneck of expressway

针对传统人驾车(HV)和网联自动车(CAV)组成混合交通条件下的快速路道路缩减瓶颈问题,从群体控制角度,提出了一种新的速度协调控制策略(简称节流控制策略);基于瓶颈交通状态和Greenshields模型,设计了领航CAV速度控制器;面向CAV节流群体组群过程的控制问题,提出了目标切换下的非线性控制器;构建了CAV节流群体类队列控制器,实现了基于瓶颈交通状态的群体形态与群体速度动态调节,进而联合领航CAV速度控制方法,周期性管控超过每组节流群体的车辆;提出了CAV纵向安全控制器来解决组群和群体演化过程的车辆安全问题。仿真结果表明:在快速路瓶颈路段下,对比传统交通系统,提出的动态节流控制策略CAV渗透率达到5%,在车流量分别为2000、3000、5000、6000 veh·h^(-1)条件下,可对应分别提高通行效率约5.87%、16.97%、11.07%、10.25%;在固定车流量为3000或6000 veh·h^(-1)的快速路混合交通瓶颈路段中,对比传统交通系统,若CAV渗透率分别为10%、20%、30%,受控交通系统的通行效率可提升约24%;通过对车头间距分析,受控CAV在节流全过程中无碰撞事故发生,且可与前车保持9 m以上安全距离。可见,节流控制策略在应对快速路瓶颈问题是有效的。

Considering the lane reduction bottleneck of expressways under mixed traffic condition composed of human-driven vehicles(HVs) and connected and automated vehicles(CAVs), a novel speed harmonization control strategy(throttling control strategy for short) was developed from the viewpoint of group control. A speed controller for the leading CAV was designed on the basis of the bottleneck traffic state and the Greenshields model. A nonlinear controller for the target changing was developed for the control during the CAV throttling group formation. A platoon-like controller for the CAV throttling group was built, and the group formation and group speed were thereby regulated dynamically according to the bottleneck traffic state. The speed control method for the leading CAV was combined to regulate the vehicles overtaking each throttling group periodically. A longitudinal safety controller for the CAV was presented to resolve the vehicle safety problem in the processes of group formation and group evolution. Simulation results show that, on the bottleneck road of the expressway, compared with the traditional traffic system, the proposed dynamic throttling control strategy is applied when the CAV penetration rate reaches 5% and vehicle flow is 2 000, 3 000, 5 000 and 6 000 veh·h^(-1), respectively, the corresponding traffic efficiency improves about 5.87%, 16.97%, 11.07%, and 10.25%, respectively. On an expressway bottleneck road with a fixed traffic flow of 3 000 or 6 000 veh·h^(-1), compared with the traditional traffic system, the traffic efficiency of the controlled traffic system can be enhanced by around 24% when the CAV penetration rate reaches 10%, 20%, and 30%, respectively. According to the analysis of space headways, the controlled CAVs can avoid collision during the entire throttling process and keep a safe distance of more than 9 m from their predecessors. Therefore, the throttling control strategy is effective in dealing with the bottleneck problem of expressway. 3 tabs, 15 figs, 30 refs.