Research On Path Planning And Tracking Control Of Automatic Parking System For Passenger Cars

With the continuous improvement of people’s living standards,every household has begun to own cars,and with the continuous increase in the number of cars,various parking lots have become more and more crowded,making parking more difficult.At the same time,due to the crowding Easy to cause traffic accidents.If all vehicles have an automatic parking function,it will solve the problem of driver parking difficulties and reduce the occurrence of traffic accidents.Therefore,the research on automatic parking systems is of great significance.The automatic parking system is divided into three layers,the perception layer,the decision-making layer,and the planning control layer.The main research content of this paper is to plan the control layer,plan a feasible parking path according to the known environmental information,and then use the path tracking controller to control the vehicle to realize the parking function.Based on the analysis of the current research status of automatic parking systems at home and abroad,an automatic parking control algorithm suitable for both parallel and vertical parking spaces is proposed for the problems existing in the path planning and tracking process.First,compare the vehicle related parameters with a certain passenger model,design the vertical and parallel parking space size according to the model,establish the vehicle kinematics model based on the Ackerman steering geometry principle,simplify the vehicle model to a monorail model,and use Simulink to build the monorail vehicle kinematics model,and compared with the vehicle model in the simulation software Car Sim,to verify the correctness of the vehicle dynamics model.Second,it analyzes the problems in the path planning process,proposes to use the traditional A* algorithm to improve,and obtains the hybrid A* algorithm,and adds the Reeds-Shepp curve to the model,and uses the Matlab script file to verify the feasibility of the algorithm.Next,the problems in the path tracking process are analyzed,and the model predictive control algorithm(MPC)is proposed for path tracking to establish an MPC controller based on the vehicle kinematics model.By adding the increment of the control quantity to the objective function,it is realized the path follows smoothly.Finally,in order to verify the functional effects of the controller,Simulink/Car Sim simulation software is used to build a joint simulation platform,and design simulation verification scenarios for parallel and vertical parking spaces,and write algorithm codes and establish control models.When the simulation verification is completed,in order to further verify the control effect of the algorithm in the real vehicle,the fullwire control chassis is used as the experimental platform,and the industrial computer is used as the controller to verify the parking effect of the model on the real vehicle.The experimental results show that the automatic parking function can be realized by the hybrid A* algorithm and the model predictive control algorithm.