Research On Vehicles Aerodynamic Characteristics,Stability And Car-Following Model Of Platoon

Since the development of Internet technology and autonomous driving technology,it has become a future trend for vehicles platoon in the Internet of vehicles.However,when a vehicle is traveling in a platoon,its aerodynamic characteristics will change,thus influencing various parameters.China has vast territory and complex terrain,vehicles on the highway will be affected by crosswind,thus affecting the stability of vehicles.In the process of vehicle platoon,the crosswind will also affect the aerodynamic parameters.In the current,the influence of aerodynamic characteristics on car-following model is also not included.Therefore,the research of this paper has significance to the development of vehicles platoon under the vehicle network in the future.This paper research the influence of distance and crosswind in vehicle platoon,and using aerodynamic characteristics to improve the car-following model.This paper can be divided into four main contents:Frist,it selects the geometric model of the vehicle,and using CFD to calculate drag coefficient of single vehicle.Compared with the standard parameters,that insures simulation results are dependable.Then through the mechanical knowledge to analysis the source of vehicle resistance,and the validity of the theory is verified by pressure diagram and vorticity diagram.Second,by setting different car spacings and the number of vehicles,the drag coefficient of the two-car platoon and the three-car platoon are obtained.Comparing it with data from a wind tunnel experiment by the University of California.A similar trend is obtained to the simulation.Then explain the variation law of drag coefficient through previous analysis of theory,then using pressure diagram and vorticity diagram to verify result.Third,by setting a fixed spacing,then using the previous simulation parameters and adding crosswinds at different angles to CFD.The six aerodynamic coefficients of each vehicle in the vehicle platoon under different crosswind angles are obtained.Then the six aerodynamic coefficients are imported to CarSim for simulation.Using fitting of a polynomial to fit the curve of six aerodynamic coefficients.In CarSim,travel paths,lateral acceleration,yaw rate and roll rate can be obtained under open-loop.The travel path,steering wheel correction angle,yaw rate and roll rate can be obtained under close-loop.The data under the two conditions are used for comparison,and the conclusions of the influence are obtainedFourth,analyzing the LWR model and the Newell model to obtain the simplified IDM model.Calculating the Q of the IDM model under different ?,then determining the ?.Then using the knowledge of mechanics and the aerodynamic characteristics are introduced to improve the IDM model,then obtaining the IDM+ model.Importing vehicle geometry parameters to Simulink,then obtaining the speed and gap of model.Finally,using the data to infer conclusions.