摘要
随着汽车技术的日益发展,汽车电子装备不断增加,进而带来汽车综合控制系统中大量的信号需实时交换的问题,传统线束已远远不能满足这种要求,因而,越来越多的汽车采用控制器局域网(CAN)。
但是,CAN总线只定义了开放式系统互连参考模型(OSI)中的物理层和数据链路层,一般用户必须直接用驱动程序操作链路层,不能直接满足复杂控制网络的组态和产品互连要求。CANopen作为一种真正开放的CAN高层协议,实现不同的CAN设备以标准化的方式进行通信,使得CAN设备具有互操作性。随着CANopen协议的日益完善,它已经广泛应用于多个行业。
本文首先介绍了CAN网络模型中各层的功能和层次结构,设计了基于CAN总线的汽车控制系统模型。该模型主要包含4个节点:发动机控制系统(EMS)、制动防抱死控制系统(ABS)、安全气囊控制系统(SRS)、车身控制系统。各个节点设计上采用内置CAN模块的飞思卡尔16位单片机作为主控芯片来搭建硬件电路,以实现CAN总线的物理层和数据链路层。设计并实现了CAN的驱动层,为各节点间的CANopen通信做准备。
然后,详细分析了CANopen应用层协议,解释了CANopen的核心——对象字典、各类通讯对象、标识符的分配,以及一些设备子协议(Device Profiles)。软件上实现了模型中各节点间的CANopen通信,完成了总线数据通讯、网络管理和相应的控制任务。
With the development of the automotive technology, the electronic devices of automobile increase rapidly, which brings the problem that it is necessary for integrated control systems to exchange the vast signals in the real-time. The traditional wiring hameses can not satisfy the development of the quest, so more and more automobile use CAN.
However, CAN-bus just define CAN physical layer and CAN data link layer of OSI communication model. Common users have to deal with the data link layer with the result that CAN chips cannot meet the requirement of configuration and product interlinkage in complicated control networks. As a completely open higher layer protocol of CAN-bus, the CANopen protocol allows different CAN devices to communicate with each other in a standardized manner and makes them interoperable. With its perfection increasingly, the CANopen protocol has been widely applied into some fields.
This article firstly introduced the layers structure and each layer function of CAN-bus's network model and designed the automobile control system model based on CAN-bus. The model divided into four nodes, including EMS, ABS, SRS and body control system. Through using 16-bit freescale MCU embedded CAN controller as master chip in each node, it achieved the design of hardware circuit, so realized CAN physical layer and CAN data link layer. It also designed and finished the CAN driver layer, laying the foundation for the CANopen communication among the nodes.
Secondly this article analyzed the CANopen application layer protocol in detail. It explained the core of CANopen—object dictionary, all kinds of communication objects, the allocation of COB-ID and some device profiles. Then it realized CANopen communication among the nodes in the model through software, and finished the bus data communication, network management, as well as its corresponding mission in control.
引文
[1]阳宪惠,现场总线技术及其应用,北京:清华大学出版社,1999,309-310
[2]CiA,CANopen Application layer and communication profile,draft standard 301,Version 4.02,2002
[3]M.Farsi,K.Ratcliff,Manuel Barbosa,An introduction to CANopen,Computer&Control Engineering Journal,August 1999:161-168
[4]贺平,计算机网络基础,北京:机械工业出版社,2003
[5]饶运涛,邹继军,王进宏,等,现场总线CAN原理与应用技术(第2版),北京:北京航空航天大学出版社,2007,21-404
[6]H.Boterenbrood,CANopen:high-level protocol for CAN-bus,NIKHEF,Amsterdam,March 20,2000
[7]史久根,等,CAN现场总线系统设计技术,北京:国防工业出版社,2004
[8]王贵建,基于CAN总线的分布式发动机控制系统设计,工程硕士学位论文,哈尔滨工程大学,2006
[9]凌永成,于京诺,汽车电子控制技术,北京:北京大学出版社,2006
[10]王绍铣,夏群生,李建秋,等,汽车电子学,北京:清华大学出版社,2005
[11]李传志,汽车车身电子控制系统,北京:机械工业出版社,2005
[12]陈宁,CAN总线技术在汽车局域网中的应用,客车技术与研究,2006(3):11-12
[13]吁苗,CAN总线在汽车车身控制中的应用,电子元器件应用,2006(4):63-64
[14]张幽彤,陈宝江,翟涌,等,汽车电子技术原理及应用,北京:北京理工大学出版社,2006,133-214
[15]秦贵和,车上网络技术,北京:机械工业出版社,2003
[16]吴诰珪,汽车电子控制技术和车内局域网,北京:电子工业出版社,2003
[17]邵贝贝,单片机嵌入式应用的在线开发方法,北京:清华大学出版社,2004
[18]MC9S12DT128B Device User Guide V01.09.S12DT128BDGV1/D,2001
[19]MSCAN Block Guide V02.14.S12MSCANV2/D,1998
[20]PHILIPS Semiconductors,PCA82C250 CAN controller interface data sheet,1997
[21]高义军,现代汽车电子技术,北京:人民交通出版社,2005
[22]曹红兵,汽车发动机电控系统结构原理与故障诊断,北京:机械工业出版社,2007
[23]齐志鹏,汽车传感器和执行器的原理与检修,北京:人民邮电出版社,2002
[24]牛永奎,冷芳,传感器及应用,北京:北方交通大学出版社,2007
[25]鲍宇,吉淑娥,薛惠娟,汽车发动机喷油、点火控制系统信号模拟与故障诊断仪器的设计,黑龙江工程学院学报(自然科学版),2007,21(3):23-26
[26]宋年秀,杜彦蕊,汽车防抱死制动系统/安全气囊系统,北京:人民交通出版社,2004
[27]凌滨,等,车身控制CAN总线网络的设计,东北林业大学学报,2007(4):81-82
[28]李晓巍,汽车安全气囊安全系统原理与维修,技术广场,2007(17):13
[29]CAN in Automation,CANopen Communication Profile Features,2000
[30]郇极,杨斌,一种开放式的现场总线协议CANopen,制作业自动化,2002,24(10):34-38
[31]孔峰,张衡,等,基于CANopen协议的汽车控制网络初探,汽车工程,2007,29(7):594-595
