The Research Of CAN Bus Network Environment Based On The Automotive Electronics Control Network

In the course of the development and the integration of the control,computer, communication and the networking technology, the field of the information communicating is covering from the factory plant equipment to every level, such as control administration, and is becoming an enterprise information system gradually which is based on the network integration automation system. The fieldbus is the exactly one that belong to the high-technology. Nowadays, the fieldbus has becomed one of the automation technology development hot spots all of the world, and it also represented the new way of the automation technology development, it is marking a new beginning of another modern ear of the industry automation technology, and certainly, it will make great impact on this domain development. CAN bus(Controller Area Network) is the most representative of the numerous fieldbus.The structure of the CAN bus is simple and practical, it can run very stably, and has a broadly application to the industry,civil using,military and so on. In presentday automotive electronics control network, the CAN bus plays a irreplaceable part, it integrates the hulking and complex automotive communication network merely inside by using two laconic cables. Also it assures automotive control and running efficiently and reliably.But the CAN bus also has defects itself. Because of the lack of the application layer definition, it requires customers to frame specification for every system. At the sametime, the competition mechanism which is based on the priority is not complete, in the case of the communication block pessimum, the message transmission delay will bring transmission speed down seriously. In a high-speed drive car, even some ephemeral delay will make a beyond help disaster. Besides, the static schedule mechanism will make system not flexible enough, and not respond to the commandment from the decision layer dynamicly.This paper focuses on the study of the above questions based on the local automotive electronics control network which is designed by self, it has offered solution.This paper mainly discusses the following three research aspects:1,Operate against the automotive electronics control network, we study CAN bus application layer and the dispatch algorithm. In combination with present development condition of here and overseas, it introduces several mainstream CAN bus upper layer protocols---CANopen,DeviceNet,J1939. Also it advances own views about the static dispatch,dynamic dispatch,time trigger and event trigger, it offers sufficient rationale for the next work.2,The automotive electronics control network design. I designed three ECU base on the Freescale MC9S12DP256 microprocessor, Anti-lock Braking System(ABS),Electronic Power Steering(EPS),Central Body Controller, used them as the CAN bus notes, and composed control network.3,The Optimization and improvement for the CAN bus network environment. It introduced a CAN Bus dispatch algorithm which is based on the TTCAN(Time-Triggered Controller Area Network) and the dynamic priority, made the real time performance and the net quality of the system much better.