Spacing Policy And Traffic Flow Characteristics Of Intelligent And Connected Vehicle Platoon

The increasing number of vehicles brings convenience to people’s travel,they also cause series of problems such as traffic accidents,road congestion,and environmental contamination.To address the above issues,the intelligent and connected vehicle platoon,which attracts considerable attentions,has been regarded as a practical solution for its potential advantages in improving driving safety,enhancing traffic efficiency and reducing exhaust emission.As a link between the microscopic vehicle platoon and the macroscopic traffic flow phenomenon,the spacing policy is not only regarded as one of the most important parts in vehicle platoon control,but also a key part in the research of traffic flow characteristics.From the perspective of control discipline and traffic engineering,the study on the traffic flow characteristics of intelligent and connected vehicle is of great significance to provide theoretical foundation for practical application of the large scale intelligent and connected vehicles in the future.Therefore,the spacing policy and the traffic flow characteristics of the intelligent and connected vehicle are studied in this paper.The main work of this dissertation is as follows:(1)Considering the influence of the relative velocity fluctuation between consecutive vehicles in the intelligent and connected vehicle platoon,the velocity difference related spacing policy is proposed to overcome the excessive velocity change for the constant spacing policy and the frequent velocity fluctuation for the constant time headway spacing policy.Then,the control algorithm is given to guarantee internal stability and string stability.Finally,simulation results show that the designed spacing policy and the control algorithm can not only enhance the tracking performance,fuel economy and ride comfort,but also improve traffic capacity and traffic flow.(2)Considering the effect of the driver’s reaction time on vehicle platoon stability and traffic flow characteristics,the spacing policy with reaction time is developed to enhance traffic capacity and driving safety.Then,the control algorithm is designed to achieve the vehicle platoon under the desired spacing policy.Finally,the numerical simulations illustrate that increasing inter-vehicle distance can promote driving safety and self-relieving ability of traffic congestion,but reduce traffic capacity.In addition,the velocity of the maximum traffic capacity is inversely proportional to the reaction time.(3)Considering the impact of data packet loss on the string stability of the intelligent and connected vehicle platoon,the spacing policy with data packet loss is given to improve string stability and traffic flow characteristics.Then,the control algorithm,ensuring the internal stability and the string stability,is designed.Finally,simulations reveal that the string stability of intelligent and connected vehicle platoon can be satisfied and the traffic capacity,traffic flow stability and hysteresis are basically unchanged when the data packet loss is smaller than the maximum data packet loss tolerance rate.