The Study On Cooperative Adaptive Cruise Control Considering Vehicle Longitudinal And Lateral String Stability

Cooperative Adaptive Cruise Control(CACC)is a vehicle platooning assistance driving system which developed on the basis of traditional Adaptive Cruise Control(ACC)technology that integrates a new generation of sensor technology and communication technology.It adds the feed-forward information of vehicle-to-vehicle(V2V)communication to the control structure of adaptive cruise,which can enable the vehicles in the vehicle platoon to respond more quickly to emergencies,maintain a smaller following distance between vehicles,and improve the safety and comfort of vehicle driving and increase road traffic efficiency.However,most of the current cooperative adaptive cruise control strategies focus on the longitudinal control of the vehicle.while faced with complex and changeable environment during the actual driving process,the vehicle inevitably needs lateral control.Moreover,only considering the longitudinal feed-forward information of the front vehicle is bound to cause waste of the interactive information of vehicle-to-vehicle communication,thereby affecting the control performance of the vehicle.In order to solve the above problems,a cooperative adaptive cruise control strategy based on H infinity theory and MPC control principle is proposed,which considers the string stability of the lateral and longitudinal of the platoon.This strategy can ensure the longitudinal and lateral string stability of the CACC queue while taking into account the following,safety,comfort and economy of the vehicle.It provides new ideas for cooperative adaptive cruise control.The principle,characteristics and control effects of different communication topologies and the different performance requirements and evaluation indicators of cooperative adaptive cruise control are analyzed,the string stability conditions of the cooperative adaptive cruise control system are derived,and the overall framework of the longitudinal and lateral integrated control of cooperative adaptive cruise is designed to provide a basis for the design of the controller.Based on the concept of string stability of cooperative adaptive cruise control,aiming at the longitudinal control problem of cooperative adaptive cruise control system,considering the influence of communication delay and the performance index of vehicle following control,the following distance strategy and longitudinal dynamic equation of vehicle queue members are established.At the same time,the one vehicle looking-forward topology structure,the vehicle dynamic model and the vehicle spacing strategy are integrated into the classic structural framework of H infinite control.Then the CACC longitudinal control structure is established to realize the relevant longitudinal performance requirements of the driving queue of the cooperative adaptive cruise control.Analogous with the longitudinal string stability requirements of traditional cooperative adaptive cruise control system,the lateral control requirements and performance indicators of the cooperative adaptive cruise control system are defined for the lateral control problem of CACC system.The MPC controller is designed to deal with the longitudinal and lateral coupling problem during the driving process,and restricts the environmental impact and its own structural performance during the driving process,so as to realize the prediction of the speed of the controlled vehicle.Aiming at the lateral control target of vehicle queue,the vehicle dynamics model and lateral distance error of vehicle following model are established,then the vehicle model and lateral control performance index are combined with the H infinity control principle based on the prediction speed,and the vehicle queue lateral string stability control structure is designed to ensure the lateral string stability and following performance.Integrates collaborative adaptive patrolBy integrating the CACC longitudinal controller and lateral controller,the longitudinal and lateral integrated control structure of the CACC system is established.Using Matlab&Simulink,the multi-vehicle cooperative control platoon was built,and different driving scenes were established to verify the feasibility of the designed control structure.At the same time,the traditional PID control and single point preview control of the vehicle platoon were built,and the control effect of the designed controller was compared,and the excellent performance of the designed controller is verified.