Research On The Path Planning And Tracking Control Of Automatic Parking

With the increasing of car ownership and the concept of "new four modernizations",the concepts of intelligent and networking make the public focus on the intelligent auxiliary systems that including automatic parking.As a typical representative of intelligent assistant system,automatic parking system has become a research hotspot.This paper studies the automatic parking system by path planning and tracking control.Firstly,a kinematic model with 2d of freedom of vehicle is established by the analysis of the motion of the vehicle in the parking process.According to the characteristics of parking spaces,this paper discusses the methods of detecting parallel parking spaces,vertical parking spaces and inclined parking spaces by ultrasonic sensor,and the parking space detection method of combining ultrasonic sensor and visual sensor.Secondly,according to the characteristics of parallel parking space,vertical parking space and inclined parking space,the corresponding paths based on arc line are planned.And then the minimum parking space size is determined according to the geometric relationship and the parameters of vehicles.Through the obstacle avoidance analysis of parallel parking space,vertical parking space and inclined parking space,the corresponding parking starting area is determined.When the vehicle is located in the starting area,the turning radius of the vehicle changes with the change of the initial position,which solves the problem of parking path planning limited by the starting position.Then,the vehicle path is tracked by the fuzzy control.According to the knowledge and experience of the driver and experts,the appropriate membership function and fuzzy logic and the appropriate variable value are insured as the input and output of the fuzzy controller.Then,through the simulation model of the automatic parking system tracking control,the parking paths of three parking spaces are tracked and controlled respectively,which verifies the rationality and effectiveness of the fuzzy controller.Finally,a test platform based on a passenger car is built.According to the proposed parking scheme,parking space identification and real vehicle experiments of parallel parking,vertical parking and inclined parking are carried out to verify the parking space detection and path planning method.