Study On CAN Communication Of Electronic Stability Control For Car

Electronic Stability Control (ESC) is an important milestone of the development of vehicle active safety, the rate of automobile accidents was greatly reduced. ESC is one of the hotspots in current automotive technology study. It is more complex compared with the previous safety technologies such as ABS and TCS,more sensors, more needed signals, more communication with other modules. One of the key technologies is the high-speed and accurate communication, which is one of the most key skills to guarantee the stable running of ESC. CAN bus has been adopted abroad and has great potential because of its beauty of structuring network and communication capability. So they will be researched together. Advanced communication network technology is applied in the car, the real-time transmission problem is solved. All the data transmission can be achieved with two lines, which make the transmission lines simply, reliability has been greatly improved, installation space and system cost are effectively saved.Based on the corresponding research achievements abroad and domestic status of the technology, the CAN communication of ESC for car is studied in this paper, everything has the traits, ESC communication network is built based on the car network, the related protocol for ESC communication network is instituted. The popular international software CANoe is selected to simulate and validate. The next step is the software and hardware design of the nodes, the system is completed partly, Specific research are as follows: Firstly network protocol, the foundation of CAN Bus, is studied detailedly. CAN2.0 specification is analyzed, such as version type, the hierarchical structure, frame structure, frame type, and communicable principles. ISO11898 standard is briefly introduced, the original services language, physical layer and monitoring some bus failure also was analyzed. The in-depth study of network protocol lay a theoretical theory foundation for the further work of this paper.Before the design of CAN communication in ESC, we should analyze the function requirements and the control strategy of the system, on the foundation of which, the design of physical layer structure and the design of data link and application layer is put forward. This paper puts focus on the application layer design, the identifier of 11 bits are defined. Based on the priorities the address of every node is defined, then transmission signal and message of ESC system is put forward.Followed the basic design ideas, the rationality and feasibility of the protocol needed to be verified after the network structure and protocol is established. It is validated through the simulation with CANoe of Vector Informatik, in the process, database is built with CANdb++, node modules are deployed, communicate of the nodes is realized with CAPL language. The simulation result shows that when communicating with this protocol, the performance of network communication is good, the busload and transmitting cycle delay are in the range of normal communication. Also, the busload will be smaller when actually communicating. Thus, the protocol design is feasible.The next step is the software and hardware design of the nodes, which is the material step for realizing CAN communication of ESC. First the network characters is determined, state and transition diagram is draw, every state is described , voltage level is assure, error detection is programmed, dectected failure is handed. All of which make a foundation for software and hardware design.The hardware was chosen firstly in the hardware design phase, the 16 bits single chip of MC9S12DP256 is applied here, which has a CAN block as CAN controller.TJA1050 is applied as high speed transceiver. Central control unit circuit is designed, including power supply block and CAN bus interface circuit. In the circuit of CAN bus interface, optical couplers insulation are applied to shield interfere.And the software design of CAN communication block involves initialization of msCAN block and message transmitting/receiving. The idiographic software flow charts are given in this paper and illuminated in term of software design principle. Next,the second phase of CAN network, system realized partly. Start physics nodes and CANoe simulation setting, the condition of the bus is observed, finally the partly node is bring to success.To summarize, this paper offers a powerful assist for further research. With the development of the modem electronic technology and the widely use of it in car field, the electronic level of automobile is improving continually, the blocking and intelligence CAN network is the way for automobile electronic. Develop a communication network system by CAN bus is a chance to shorten the Chinese and foreign automotive technology gap. With the development this paper establishes the foundation for future analyses and development of CAN communication in electronic controlled system.