Development Of A Car's Body Control System Based On CAN Bus

Nowadays the electronic part takes a great portion of a car's cost and will become much bigger. The cars nowadays take more emphasize on comfortability, safety, real time etc. But these are implemented by the car's electronic module on a great portion. The BCM module discussed in this paper is to implement the control of the electronic parts in and out of the car. The BCM module based on CAN can realize the control of exterior lights, interior lights, wash wiper, central lock, windows etc. This module can operate by the control logic set by the software to control these objects. When the conditions are reached, then will trigger the corresponding command to control the relays. In the software, it realized configurable, updateable function and easy to maintain and the function upgrade.The paper begins from the basic topology and work principle of the body control system based on CAN. The paper also analyzes and discusses the system's hardware structure, parameter selection, control strategy and the software realization. Base on these, the paper designs the intelligent CAN node which has the control function of the interior and exterior lights, central locking system, wash wiper system, window lift system. Meanwhile the intelligent CAN node has self-protection function. The control software of each intelligent node is designed according to the development workflow of vehicle electronic. The software architechture of the software contains low-level hardware abstract layer,standard MCU drive library function layer and control application layer. According to the circuit function, power circuit, high and low side drive circuit, switch input filting circuit, MCU peripheral circuit and extend EEPROM circuit.The BCM module has been installed on the ROEWE car styles which are produced by SAIC. This module also has been debugged and tested, the results show that this module not only satisfies the body control's function requirements and cut off the cost and reduce the complicated wiring harness and makes it easy to maintain. At the same time, this module realizes the object of the control conponents'intelligence and body control system based on network. In this system, besides each intelligent node can shares the datas, many new functions such as the windows'anti-pinch function, remote locking control has been added. For the safety of the module, redundant back up and watch dog functions have been developed. Because this module controls the car's body electronic systems, the requirement for safety is quite high, before formal production, this module has to be tested strictly, these tests include function test, bench test, salt fog test, crash test, EMC test, real car test etc. The body control module in this project has totally passed the tests above and satisfied the requirements of SAIC and has been installed in the cars. This module has been produced successfully now.Practice show that the body control system base on CAN bus is a technique with revolutionary and can lead the car's electronic, intelligent trend. The network data communication has the obvious advantages as real time, reliable, easy connect, multi-stations, simple communication protocol and high function price rate. The car's body control system based on CAN bus certainly will be one of the standard configures on the intelligent cars for the future.