Research Of Car Reversing Aid System Base On CAN Bus

Along with the automotive industry development and standard of living improvement,consumption of cars increases year by year. There are more and more new drivers in China.It’s difficult for them to reversing easily due to view angle and space is limit in car. Moreand more car accidents happened due to reversing. Therefore the difficulty of car reversinghas been given abroad attention by drivers, car makers and related suppliers. Car reversingaid system is an electronic intelligent monitoring system, which is able to detect the distancebetween barrier and car then output steering angle prompt while parking and reversing. Carreversing aid system will also alarm once the distance between car and barrier reach toassumed safety distance value. Therefore drivers can control the car to keep safety distancewith barrier while reversing to avoid any car crash, even if they can not really see the barrier.Reversing action changes to more safetly than befor with the system.This thesis has a deep discussion and research on application of car reversing aidsystem base on CAN bus. There are mainly five models of this system, including ultrasonicdistance detector, distance detecting controller, host controller, LED display and buzzeralarm equipment. Distance detecting controller exchanges data with ultrasonic distancedetector through RS232serial ports and transfers barrier distance information to hostcontroller constantly in real time. Host controller combines distance value information fromall ultrasonic distance detectors to work out car steering angle using fuzzy control algorithmand drive buzzer to alarm at same time.This thesis do research of two parts of content, including the hardware design andsoftware implementation of CAN bus communication web, and the design of reversing fuzzycontroller making use of MATLAB.CAN bus is an open multiple host serial-bus communication specification. Singleelectronic equipments is a normal node, which composes the whole CAN web. All the nodes are able to share data with each other. In this system, six distance detecting controllers andone host controller compose a CAN communication web as nodes. The hardware of eachsingle controller is consisted of ARM_LM3S2965micro processor as key part andCTM8251AT as transceiver. The software that under Keil-uVision3integrated developmentenvironment is written, debugged and burned using C programming language. Fuzzy controlalgorithm program, display and buzzer driving program are realized in host controller.In this paper, car reversing aid system fuzzy control model is established. Input variableis distance between car and barrier. Output variable is car streeing angle. Input and outputvariable value choosing range and subjection function are established by using Matlab fuzzylogic tooling box. Then experts experience extracted from car reversing action is used toestablish and edit fuzzy control rules. Thus reversing fuzzy controller is set up. Makesimulation to fuzzy control model in “Simulink” to validate fuzzy control algorithmic isvalid.At the end of the thesis, we test the car reversing aid system base on hardware and getconclusion that CAN bus web is stable, safety and constant. Reversing fuzzy control methodis easy to be realized, credibility and supply validity operation indication. The performanceof this system can satisfy the design target.