Study On Modeling And Controling Of Autonomous Vehicles Platoon Under The Influence Of The Communication Network

As one of the important research areas of Intelligent Transportation System(ITS),Automated Highway System(AHS) has the potential to improve operational efficiency of traffic, enhance traffic safety, reduce energy consumption, cut back on traffic accidents and other numerous advantages and become a hot topic of innovation and research. A primary means to fully realized Automated Highway System is based on the method of Automated Vehicle Control Systems(AVCS). In this control method, final take measures for vehicle control(steering, throttle, brakes, etc.) can easily achieved by measuring the traveling condition of the vehicle itself(such as the lateral error, velocity, acceleration, etc.)and the traveling environment information of preceeding vehicles(such as inter-vehicle distance, relative speed, acceleration of leader vehicle, etc.). In theory, by such a method can achieve the above object satisfactorily.In this thesis, we carried out research deeply on modeling and control of autonomous vehicles platoon based on analysis and combing the research achievement of existing Automated Highway System. Finally, we proposed one solution which can ensure the stability of system when the system has the possibility to face with new situation such as communication packet dropout. The main contents of this thesis are as follows:First, research status analysis is conducted. We adopted a more comprehensive overview on the basic concepts of modeling and control of autonomous vehicles platoon,specific methods, current research situation and existing problems.Second, vehicle longitudinal and lateral model is established. We summarize and analysis the advantages and disadvantages of the existing models of longitudinal and lateral vehicles control, and then proposed the adopted model which has optimize the current model and in favour of controller design. The adopted model including vehicle lateral dynamics model based on the lateral error, vehicle longitudinal dynamics model in view of Newton’s second law of kinematics and the structural model of the vehicles platoon under ideal communication network environment.Third, vehicle platoon control problem under ideal communication condition is considered. Under the ideal communication condition, we will design a lane keeping controller using state feedback and output feedback method for lateral control, and then analysis the reasons of steady-state error use simulation tools. For longitudinal control, we will propose a kind of platoon controller included a PID controller and a Lyapunov controller respectively, and then analysis the string stability of the vehicles platoon. At last,we compared the difference between the different longitudinal control methods, such as the response to initial spacing errors and adaptability to sudden speed change of leader vehicle.Fourth, the problem of vehicle platoon controller design is studied under the influence of communication packet dropout condition. Under such conditions, we considered the communication packet dropout of the leader vehicle’s information as a stochastic Bernoulli model, and then designed a dynamic output feedback controller which can assure the system is stable on the basis of establishment of a hybrid control model of vehicle platoon.Further more, we consider a more complicated situation of both communication pocket dropout and shifting interference of leader vehicle exist. And then, the condition of a H∞controller exists is provided by means of LMI method which is verified by simulation result.Finally, the full text were generally summarized, and we discuss some open problems which need further research.