Research On Automotive Body Control Module Based On Can Bus

With the development of automotive electronics and embedded technologies, automotive body control is gradually toward the networked and intelligent direction. Because of its low cost,high reliability and real time characteristics, CAN bus is widely used in automotive electronic systems. And the CANopen protocol, which is the high level protocol of CAN bus, is widely recognized and applied to automotive control systems for its high degree of flexibility and configurability. The purpose of this research topic is to design a automotive body control system based on CAN bus.First of all, A brief description of the development of automotive network based on CAN bus is provided. According to the hierarchical structure, the important content of CAN protocol is analysised in detail. After a study for the body control system network topology and the functional requirements of the system, a overall scheme of automotive body control system is presented.Secondly, CANopen Protocol which is the application layer protocol of CAN bus is introduced. According to the needs of automotive body control system, The specific needs of each control node in the system is analysised. The CANopen protocol stack of automotive body control system is developed, including object dictionary, network management(NMT), Service Data Object(SDO) and Process Data Object(PDO).Then, depending on the overall scheme of the hardware system, we completed the structural design for the automotive body control systems, and established the electrical characteristic of the control objects and parameters of each module and their control function. The anti-interference of hardware circuit is designed. Also, the hardware circuit board design and production are completed. According to the needs of real-time and reliability of the system, μC/OS-II real-time operating system is introduced to the automotive body control system, modular design of the software is compeleted. The MicroCANopen protocol stack is analysised in detail, the stable operation of MicroCANopen protocol stack in μC/OS-II real-time operating system is realized.Finally, the test platform of automotive body control system is built, and a preliminary test of the system is implemented. And then the communication of NMT messages, PDO messages and SDO messages are tested, which verify the feasibility and correctness of this design scheme.