| This paper mainly conducts related research on the vertical parking system of vehicles,and focuses on three core technologies of automatic parking system parking space recognition and parking path planning and path tracking.A kind of parking line recognition algorithm based on image processing technology is proposed in this paper,and then the path planning of the vertical parking is carried out and the path tracking controller is designed in this paper.The vertical parking simulation is carried out by using the vehicle dynamics software,which will provide some reference for studying the vertical parking of the vehicle.First,this paper completes the identification and analysis of vertical parking spaces with parking lines.Various parking scenes,such as different lighting conditions,different parking backgrounds and different types of parking lines are were collected,and a kind of recognition algorithm of parking lines based on Hough line transformation is proposed,which is identifying the parking space by detecting the straight line of the parking space,and use this algorithm to verify the parking space lines in a variety of scenes.Secondly,The vertical parking motion process was analyzed,and the kinematics model of the vehicle was established based on the parameters of a passenger car,at the same time,the vehicle kinematics was analyzed based on Ackerman steering geometry,and the trajectory of each point of the vehicle contour was deduced.The Parking parameters and the road parameters were selected according to relevant standards and the theoretical starting area of parking was determined.Combining with the parameters of the referential car,the collision constraint analysis of the parking process is carried out and different parking starting areas are divided.According to the different parking starting positions of the vehicles,the parking path planning is carried out with the minimum turning radius of the vehicle.There are two different parking paths are designed for different starting areas of vehicles and different starting positions are selected for path planning simulation.Thirdly,the design of the vertical parking motion controller is completed on the basis of path planning.Basing on the PID control algorithm,the vertical parking speed controller,front wheel angle controller and body heading angle controller are designed respectively.Planning and controlling the speed of the vehicle during the parking process,and different controllers are used in different paths to ensure that the vehicle can achieve path tracking control.Finally,Carsim software is used to establish different vertical parking scenarios,and combined with Carsim vehicle dynamics model and Simulink vehicle control model to complete the joint simulation of the vertical parking system control strategy,which verified the reliability of the vertical parking control strategy proposed in this paper. |
