Design, Automotive Body Network Based On Can Bus

With the development of modern automobile technology, electronic device in vehicle body are increasing continuously. The traditional wiring harnesses can not satisfy complex functions of control systems of automobiles. As the CAN bus introduced into vehicle control system, great progress has taken place in the area of vehicle electron. By adopting CAN bus, the function of vehicle body control system was satisfied perfectly, the cost was decreased, the redundant wiring harnesses were cut down, the intellegentized and networked system was realized.In the thesis, the actuality and develop trend of vehicle electronic technology are introduced. Analysed in deeply the performance and characteristic of CAN(Controller Area Network) and SAE J1939 that are used widely in occidental auto at present. The basic topology and working theory of the vehicle body control system based on the CAN bus is introduced. Technical regulation of CAN Bus network is lucubrated and Data Link Layer and Physical Layer in hierarchy structure of CAN Bus is described. Its basic concept and orgnizing rules and particularly represents the message, frame format, error style and checking error ability in CAN Bus are simply introduced. CAN controller and transceiver were chose which are the key chips in the CAN communication.The therories and applications of CAN controller SJA1000 and transceiver PCA82C250 were analyzed in detail.According to the status of subsystem work separately, low intelligence and bad expansibility in function of auto body control module of our own vehicle, bring forward a distuibuting module control project based on CAN protocol. And realized by join 9 nodes designed to control SANTANA-LX body components into a network by CAN bus with speed 125kbit/s, and accomplish the hardware design of CAN intellective node by SJA1000 controller and PCA82C250 transceiver. The hardware and software were expolited by means of universal modularized method. Under the condition of ensuring the function commands, the processes of hardware and software designing were simplified, developed periods was shrten and the cost of system was decreased. In order to improve the stability and reliability of the electronic control system under severe electromagnetic interference environments, electromagnetic interference proofing and restrain measurements that should be applied in the design of hardware and software.Based on the analysis of SAE J1939, draw the application layer communication protocol, and provide part of sorfware. By CANoe, twisted-pair being corresponding medium, when rate is 125Kbit/s and communicating time is 24 hours, successful rate is 100%. Finally, the conclusions of the research were drawn. According as the developing trend of the vehicle electronics field, the improving and perfecting direction of the vehicle body electronic control system based CAN bus were pointed out.