Research Of Automatic Parking System Based On Laser Radar

Drive assistance system develops quickly as the city is getting more crowded and parking space becomes tighter. The research on PAS (Parking Assistance System) has important significance because it's able to provide assistance for the driver to reduce operating intensity and improve safety coefficient. In most PAS, Ultrasonic sensor is used to detect the parking pot so far, but it has a limited accuracy and cannot be applied in vertical parking mode. In this paper, upon the platform of the intelligent vehicle (IV), an automatic parking system based on laser radar is designed and implemented, which is capable of both parallel parking and vertical parking. Experiments show that this system is accurate, stable and easy to maintain.Firstly, according to the requirements of the parking task, the lower-level control system of intelligent vehicle is designed, which is the basis of automatic parking system. It is the 3rd generation control system of CyberC3 car, featuring good modularization. S12 singlechip is the core of the hardware. The design of longitudinal control module and the lateral control module is mainly presented, which are very stable. For the software, uC/OS-II operating system is chosen, while CANopen protocol is applied in the communication system of IV. This communication system has standard interface, and it's easy to expand and it can directly adapt in sensors integrated with CANopen, which makes the whole system flexible and easy to maintain.Then the control method of parallel parking is presented, which detects free parking space with high-accuracy laser radar. The parking process is: the driver leads the vehicle passing by the parking pot, while the intelligent vehicle makes free parking space detection, path planning and then follows the path to complete the parking task. The paper also designs a parking method by multiple parallel shifts when there's too little space for parking. Simulation and experiments show that: the parking space detection has high accuracy; the path planned by improved method is easy and safe to achieve; the path following method combing both forward control and backward control has a good control effect.Finally the control method of vertical parking is presented. In the same way, the parking process includes free parking space detection, path planning and path following. The localization of the vehicle is achieved by the fusion of laser radar data and lower-level sensors data with Kalman filter, making the parking process safe and accurate. Then another simple case of vertical parking is solved.