Research On Lateral Control Of Intelligent Vehicle Path Tracking

As a complex system with many high and new technologies,intelligent vehicle is an indispensable part of Intelligent Transportation System.Intelligent vehicle can not only be used in the current complex traffic conditions to ease traffic congestion and reduce traffic accidents,but also have a good application prospect in the industrial field,military field and aerospace field because of its mechanized power,which can improve work efficiency and replace human operation in harsh and harmful environment.The path tracking control technology takes a core position in the key technology of intelligent vehicle because it takes two tasks into account,one is to control the vehicle not to deviate from the path,the other is to control the vehicle speed to ensure safe driving.One of the tasks is how to control the steering of intelligent vehicle,which has become a hot and difficult issue.Therefore,this paper takes the intelligent vehicle as the research object to study its lateral control technology.Aiming at the motion characteristics of intelligent vehicle in the process of path tracking lateral control,a vehicle model with only two degrees of freedom of lateral and yaw is established.Given the ever more feedback control method is adopted to improve the lateral control research,it can only observe the current location information and can not meet the real-time requirements of the control.Therefore,this paper designs a path tracking lateral controller based on the preview control strategy to ensure that the vehicle can judge the path ahead in advance and obtain the lateral deviation and azimuth deviation,so as to better track the desired path.In addition,the obtained horizontal and azimuth deviations are fused into the integration deviation by adding weight coefficients,which lays a foundation for the design of the controller.Combined with the advantages of fuzzy and sliding mode control algorithms,the intelligent vehicle path tracking lateral controller is designed.Compared with the direct selection of error as the input of the fuzzy controller,this paper uses the sliding mode switching function composed of the integrated deviation and its differential as the input of the controller to convert the control of error into the control of sliding mode function,and tracks the desired path by the output of the front wheel angle of the fuzzy controller to reduce it to 0.The control method not only retains the outstanding advantage of fuzzy control that does not need to rely on accurate mathematical model,but also keeps the control system in two dimensions all the time to reduce the complexity of the system.At the same time,it can weaken the violent buffeting caused by high-frequency conversion near the sliding mode surface,thus ensuring the stability of the steering wheel rotation.Matlab/Simulink platform is selected to check the performance of the designed lateral controller.Firstly,the lateral controller is simulated for two reference paths,and considering that the actual path can more accurately judge the tracking effect of the path tracking lateral controller,the controller is simulated by the actual path obtained through Open Street Map.The simulation results verify that the control algorithm can play a good control effect under different path conditions.Furthermore,the robustness of the algorithm is analyzed for different vehicle speeds,loads and centroid positions,etc.The results show that the designed controller can quickly and stably reduce the deviation and has strong adaptability and robustness to the change of parameters,which meets the requirements of lateral control.