Design And Research Of Automobile Network Control System Based On CAN Bus

With the rapid development of the modern automobiles, the lasting increase of electronic devices of automobiles, the traditional wiring harnesses can not satisfy much more complexity of control systems of automobiles. The network control system for automobile is developed, which takes advantage of the technical achievements in the fields such as electronic, computer, sensor and controlling. In order to solve the questions that the automobile wiring becomes huge and complex, the system is unreliable, the difficulty of breakdown maintenance is big, A kind of automobile network control system based on CAN bus is designed. CAN bus make the real-time, stability, safety and economy of the automobile much better.As the development trend of the LAN of the automabile, CAN bus, as the representative of C class networks,will be popularized gradually and hold a dominant position.According to the characteristic of automobile electronic, based on researching the standard of CAN protocol technology , the acquisition and processing of the analog signal, digital signal and switching signal are completed; the display such as oil mass, water temperature, rotational speed, the speed of vehicle etc., alarm of overrun and control state of light is realized, A kind of CAN bridge is designed, with the aim of realizing data communication between different speed that the engine's high-speed CAN and the automobile body's low-speed.Gather various signal of the sensors to PC with RS232-CAN adapter which is designed by myself, simultaneously, PC sends the control signal to the bus, The signal is fed back to the monitoring software after the successfully controlling of the corresponding node, The communication between CAN node and PC is realized. To monitor CAN network and test CAN communication with the monitoring software of PC which is developed by Visual Basic. In the first place, this monitoring software can monitor the operation of the system, in the second place, the fault analysis is carried on.The standard of CAN has only defined the protocol of the physical layer and the data link layer, so the system establishes the application layer protocol for the automobile CAN network control. The system uses the expansion patterns of 29 identifiers, which defined two-byte identifier and one-byte data field code. Each device leaves wide resources for expansion in future when the protocol has been established.The system can transfer all the data only by using a pair of wires, which simplifies the wiring harnesses, improves the reliability and efficiency, saves space and the cost of the system. And the user can select corresponding function according to the actual needs, nodes can be dynamically increased and deleted without any changes of hardware according to the specific circumstances of automobile, which can reduce the cost of the secondary development. The test showed that it is no exception to transmit and receive message when the data transmision rate of the CAN network is reached, and this system can meet the need of the real-time of engine, as well as ordinary real-time of automobile body.