The Research And Development Of Automatic Parking Assistance System

The vigorous development of the automobile industry not only brings great convenience for people to travel,but also brings negative effects such as traffic congestion,environmental pollution and so on.The contradiction between the continuous growth of vehicles and the existing infrastructure can't meet the needs is becoming increasingly acute,a series of problems like the scarcity of parking spaces,parking difficulties are gradually exposed.According to the above problem,the automatic parking assistant system which integrates sensor technology,electronic control technology and bus communication technology arise at a historic moment,and proposed a fast and efficient solution.In this paper,a certain type of gas Honda car is used as the test carrier to study the most complex working conditions in the process of parallel parking ——multiple parallel parking,and puts forward the path planning scheme based on incremental algorithm.With reverse thinking analysis the movement laws of vehicles within the parking lot,deduce the motion trail of vehicles outside the parking space,finally the complete path of automatic parking was obtained and the GUI interface of MATLAB software is used for simulation verification.Next,through the comparison of the properties of several ranging technology,considering the ranging accuracy,installation convenience and economic cost of sensor,the SRF01 ultrasonic sensors is selected as the external environment perception module input.In order to further reduce the error which caused by the beam Angle in the process of parking space acquisition,puts forward a new way that double ultrasonic sensors working together and oblique installed on the automobile body side.The single sensor error compensation experiment which forward installed and the double sensors test which oblique installed are conducted respectively,through comparing the latter one which error value lower was chosen as the parking space collecting in this article.Then,according to the need of automatic parking assist system each function module,a hardware test platform by freescale 8-bit microcontroller MC9S08DZ60 chip as the main controller was build,and each module corresponding to software was designed.Based on the requirement of communication,the SCI serial port communication module was designed which used between parking controller and ultrasonic sensor Arduino board,also the CAN communication module which used between parking controller and EPS module was designed too.In order to control steering system of the test vehicle,the control strategy of EPS software and hardware controller was designed to replace the original EPS system.When the Bosch angle sensor was installed in the steering actuator pinion shaft,the modified work of test vehicle was finished.Finally,in order to improve the success rate of automatic parking real vehicle tests,the ultrasonic ranging test,wheel speed pulse ranging test and parking space acquisition test was carried out respectively on the test vehicle in the first place.Then analyzed the reasons of error appeared in the process of test and to compensate.The automatic parking assistant system which was developed in this paper applied to the test vehicle at last,the multiple parallel parking under the limited parking lot situation that test car length add one meter was achieved successfully,and verify the feasibility of the path planning scheme this text proposed.