Research On Vehicle Body Network System Based On CAN And LIN Bus And Its Electromagnetic Compatibility

Aiming at the problem of the unreliability and limited car space occupied by the wire raise and the increasing of ECU units in the automotive, this paper makes intensive study on the technology of automotive bus network. With the analysis of actual system working environment and functional requirement of each node, the vehicle body network system based on CAN/LIN bus is designed. Meanwhile, against the electromagnetic compatibility problems caused by high frequency and speed, the simulation design method on electromagnetic compatibility called by "top to down" is proposed in its hardware design. The automotive body network system actualizes the lightweight body design and improves the vehicle intelligence and electromagnetic compatibility. The major work of this paper is the hardware and software design of vehicle body network system as well as its electromagnetic compatibility simulation study.Ⅰ. Its hardware design includes:Central control module: the Freescale microcontroller MC9S08DZ60which has embedded CAN in the lowest cost is adopted as the ECU. It can directly communicate with the CAN gateway with the advantages of low cost and convenience.Network control module design: It includes CAN module, LIN module and CAN/LIN gateway. The rate of data transmission is raised in the matching between gateway and two buses in order to achieve the communication between the CAN bus and LIN bus.Bottom control module design: The four nodes of lights, windows, locks, and car rearview mirror are designed. Among these modules, the car rearview mirror node is controlled by the LIN bus and the rest ones are controlled by the CAN bus control, ultimately achieving the functional requirement of each node.Ⅱ. Its software design:This paper, using CAN2.0B specification (ISO11898) and LIN2.0specification as the standard, designs the software platform of vehicle body network system adopting SAE J1939as the application layer protocol and applying the modularization idea. It respectively put on software design on the lights、windows、locks、 and car rearview mirror, lights intelligent switch control, actualize the application function of intelligent control of lighting switch, anti clip window, central control of door lock, automatic unlocking/locking and so on.Ⅲ. The network system of the body the PCB on EMC:The method combining the software Altium Designer with Ansoft Designer is adopted to conduct simulation analysis of PCB electromagnetic field. According to the simulation analysis curves, the electromagnetic compatibility of PCB can be optimized and improved, enhancing the EMC of products.This paper is developed by the horizontal issue named "intelligent vehicle body network system". The project includes the previous network topology and analysis of node needs, hardware design, application function analysis, software design and latter performance test.