Study On Lateral,Longitudinal And Integrated Control Strategy Of Intelligent Vehicles Based On Dynamic Model

Intelligent vehicle is a typical high-tech fusion system integrating computer science,visual sensing,multi-information fusion,communication,automatic control and so on.It has become a new direction for the future research of vehicle and the development of automobile industry.As an important part of intelligent transportation system,Intelligent vehicle can improve the road traffic capacity and reduce the occurrence of traffic accidents,the rapid use of intelligent vehicles can solve the increasingly serious traffic problems,but there are still many problems need to further study and solve at present.Motion control is one of the core problems in the field of intelligent vehicle research and is the basis of other related research,including lateral control,longitudinal control and integrated control.Based on the lateral and longitudinal dynamic model,this paper studies the design of feasibly and stably lateral,longitudinal and integrated control system.Theoretical knowledge is the basis of research.Under the guidance of the instructor,the system architecture of the intelligent vehicle is established,including the perception and recognition layer,the decision control layer and the execution layer.The mathematical principle,basic control structure of fuzzy control logic and fuzzy controller design method are expounded.The basic principle of PID controller,the influence of control parameters on control effect and the method of parameter setting are expounded.As a basis for the study of control systems,the establishment of lateral and longitudinal dynamic models are of paramount importance.In this paper,a two-degree-of-freedom lateral dynamic model is established based on the control target state variables of vehicle lateral control.Based on certain assumptions and simplification conditions,the longitudinal dynamic model is established by combining the longitudinal mechanical model and the driving dynamics model.Based on Carsim software,the integrated control physical model is built.The design of the longitudinal control system is carried out by using the direct control structure.The design of accelerator pedal controller and the brake pedal controller use the fuzzy control logic,and use PI control parameter to optimize the fuzzy controller,and design switching control logic to coordinate the accelerator pedal with the brake pedal.The simulation results show that the designed accelerator pedaland brake pedal controller and the coordinated switching strategy can ensure that the vehicle can achieve the desired acceleration and deceleration action,and the vehicle speed tracking effect is better and the design of longitudinal control strategy is feasible and reliable.Design of intelligent vehicle lateral control system is based on the theory of preview,fuzzy control logic and PD control.Firstly,the road-vehicle dynamics model is set up,and the PD lateral acceleration tracker is designed based on the optimal preview driver theory and model,so that the vehicle lateral control system is obtained.The fuzzy optimal controller is constructed of which the preview distance is adaptive selected,so the adaptive preview process of lateral control is realized.The simulation results show that the adaptive preview method can reduce the lateral displacement deviation and the heading angle deviation,and improve the vehicle lateral tracking accuracy and lateral stability by dynamically adjusting the preview distance.In order to further verify the control effect of the lateral and longitudinal controller in the case of variable speed condition,this paper combine the lateral controller with the longitudinal controller system,and optimize the control system parameters to construct the integrated control system.The integrated control model system is built by Carsim and MATLAB.The simulation results show that the integrated controller can eliminate the influence between the lateral and the longitudinal motion,and coordinate the lateral and longitudinal integrated control,and certify the feasibility of the lateral controller and longitudinal controller again.