Research On Automatic Parking Path Planning Technology

In recent years, with the rapid development of the industry and the improvementof people’s living standard, the number of the car has greatly increased. The parkingspace for drivers sharply reduced, at the same time, more and more new drivers get thedriving license. They are not good at driving and can not stop the car in the right place.Then, the accidents are especially prone to occur when reversing the car for these lessexperience drivers. How to reverse the car safety, much rapid, has become a new focus.Therefore, the vehicle automatic management is necessary, which has become a newdirection of the industrial development. Then, the automatic parking system arises inthis trend.The paper studies the automatic parking path planning. First of all, according tothe vehicle kinematics characteristic, the vehicle kinematics model is created when thecar is at a low speed. Combined with the nonlinear constraint problem in the vehiclemovement, the possibility of collision points are analyzed in the process of parallel andvertical parking, and the avoid collisions area for the parking path is also given out. Onthis basis, the key point and the minimum parking space in parallel parking is solvedand two tangent arc path planning method is put forward, and then the simulationanalysis was carried out. In the vertical parking path planning process, three differentparking path types of two-step, three-step and direct reverse based on geometricrelationship are put forward and the comparison of these three parking path is alsogiven out. In order to solve the discontinuity problem of the path, Bezier curve isadopted to optimize the planned path. The simulation analysis proves that the parkingpath is smooth by using Bezier curve to optimize.Aiming at the shortcomings to track the parking path by using PID control andfuzzy control method, on the basis of the nonlinear input/output feedback linearizationcontrol, the self-organizing fuzzy controller with learning ability has been designed,the controller track the path through continuous correction of front wheel steering- angle command, and the controller has the high control efficiency and excellentcontrol effect. Both the self-organizing fuzzy controller and the non-linear feedbacklinearization controller are used to track the parallel parking trajectory which based onsinusoidal function. Then, we give the comparison to the effect of two kind controllers.The simulation results show that by using self-organizing fuzzy controller, the systemimproves the stability of the system. The experiment results also show that thisintelligent controller can achieve reasonable tracking control accuracy with small error.According to the requirements of automatic parking system, the power drivecircuit, control circuit, ultrasonic ranging circuit and video image acquisition andprocessing circuit are designed. Each module of the software process is given finally.