自适应巡航控制车辆跟驰模型综述

Review of car-following models of adaptive cruise control

分析了自动驾驶汽车自适应巡航控制(Adaptive Cruise Control,ACC)和协同自适应巡航控制(Cooperative Adaptive Cruise Control,CACC)车辆跟驰模型,从系统控制原理、车车通信技术与车间时距方面阐述了ACC与CACC车辆的异同点;将目前主流ACC/CACC车辆跟驰模型分为3类:基于智能驾驶的车辆跟驰模型、加州伯克利大学PATH实验室车辆跟驰模型与基于控制论的车辆跟驰模型,总结3类车辆跟驰模型的建模思路与主要优缺点;从道路通行能力、交通安全和交通流稳定性3方面,分析了ACC/CACC车辆对交通流特性的影响,及其研究现状与未来发展趋势。研究结果表明:不同的ACC/CACC车辆跟驰模型对通行能力的影响存在较大差别,ACC/CACC车辆有利于提升交通安全性,但由于缺乏统一的安全性评价指标,难以量化ACC/CACC车辆对交通安全性的影响程度;小规模实车试验验证了ACC车辆具有不稳定的交通流特性,否定了ACC车辆稳定性数值仿真结果,而数值仿真试验和小规模实车试验均表明CACC车辆可较好提升交通流稳定性,因此,完全依赖于计算机仿真试验无法获得令人信服的结论,实车试验是ACC/CACC研究的必要途径;为了完善ACC/CACC在交通领域的研究,应构建不同ACC/CACC车辆比例下的混合交通流基本图模型、智能网联环境下的ACC/CACC车辆跟驰模型建模方法与ACC/CACC混合交通流稳定性解析方法。

The car-following models of adaptive cruise control（ACC）and cooperative adaptive cruise control（CACC）of autonomous vehicles were analyzed.From the aspects of system control principle,vehicle-to-vehicle communication technology and vehicle time-gap,the similarities and differences of ACC and CACC vehicles were expounded.The mainstream car-following models ofACC/CACC vehicles at present were divided into 3 categories：the car-following model based on intelligent drive,the car-following model of PATH laboratory of University of California,Berkeley,and the car-following model based on control theory.The modeling ideas of the 3 categories of car-following models were summarized,and their merits and drawbacks were also expounded.Representative achievements about the impacts of ACC/CACC vehicles on traffic flow characteristics were reviewed from 3 aspects of road capacity,traffic safety,and traffic flow stability.Then,the research status of this field was formed.Meanwhile,the future development trend was pointed out.Research result shows that the impacts of different ACC/CACC carfollowing models on road capacity have relatively big difference.ACC/CACC vehicles are helpful to improve traffic safety.However,because the uniform index of safety evaluation is absent,it is difficult to quantitatively evaluate the impacts of ACC/CACC vehicles on traffic safety.Small scale real vehicle tests validate that ACC vehicles have unstable traffic flow characteristics.The tests reject the numerical simulation-based results of ACC vehicles stability.But both numerical simulations and small scale real vehicle tests show that CACC vehicles can improve traffic flow stability well.Therefore,convincing conclusions are unable to be obtained based on computer simulations absolutely.Real vehicle tests are the necessary way of ACC/CACC research.In order to perfect the research of ACC/CACC in this field,the fundamental diagram models of mixed traffic flow with different proportions of ACC/CACC vehicles,the modeling methods for ACC/CACC car-following models in the intelligent and connected environment and the stability analysis methods for ACC/CACC mixed traffic flow should be built.