不可靠通信条件下的CACC纵向控制仿真分析

Simulation Analysis of Longitudinal Control of CACC under Unreliable Communication

近年来基于车联网技术实现的协同式自适应巡航控制(cooperative adaptive cruise control, CACC)已经成为重要的智能网联汽车应用场景。CACC系统的有效性依赖于基于车联网通信实现的车辆速度、加速度等信息的实时、可靠交互,然而受各类天气条件及行车环境的影响,理想、可靠的通信环境难以在实际交通场景中实现。因此迫切需要在不可靠通信条件下对CACC的适应性进行评估分析,以研究不可靠通信条件对CACC模型的影响。针对上述问题,首先围绕测试评估需求,分析了三种典型CACC跟驰模型;其次,基于Veins平台搭建仿真测试环境,并在选取通信延迟和丢包率为不可靠通信条件的基础上设计了测试方法;最后,在头车速度正弦变化和头车紧急刹车两种应用场景下,仿真测试研究了不可靠通信条件对三种典型CACC跟驰模型的影响。仿真结果表明,通信延迟和丢包率都会影响CACC的可靠性,当丢包率达到5%或时延达到5 ms时,对CACC队列稳定性有显著影响;从总体上看,Rajamani控制模型的效果最好,Ploeg控制模型的效果最差。

In recent years,cooperative adaptive cruise control(CACC)based on V2X technology has become an important application scene of intelligent connected vehicles.The effectiveness of the CACC system depends on real-time and reliable interaction of vehicle speed,acceleration and other information based on vehicle networking communication.However,affected by various weather conditions and driving environment,ideal and reliable communication environment is difficult to be realized in actual traffic scenes.Therefore,it is urgent to evaluate and analyze the adaptability of CACC under unreliable communication conditions,so as to study the influence of unreliable communication conditions on CACC model.To solve the above problems,three typical CACC car-following models are analyzed around test evaluation requirements.Secondly,the simulation test environment is built based on the veins platform,and the test method is designed on the basis of selecting communication delay and packet loss rate as unreliable communication conditions.Finally,in the two application scenarios of the sine change of the leading vehicle speed and the emergency braking of the leading vehicle,the simulation test studies the impact of unreliable communication conditions on three typical CACC car-following models.The simulation shows that both communication delay and packet loss rate can affect the reliability of CACC.When packet loss rate reaches five percent or delay reaches five ms,it has a significant impact on the stability of CACC queue.Generally speaking,among the three control models of Rajamani,S.Santini and Ploeg,Rajamani control model has the best effect,while Ploeg control model has the worst effect.