Development Of Network For Intelligent Electrical & Electronic Bus

Intelligent Electrical and Electronic Device System (IEEDS) intelligentizes all electrical and electronic devices all over the bus, each of which has electronic controlling and self-diagnostics functions, and connects to the network bus via standard interface; thereby the electrical device system of the whole bus is networked, standardized and intelligentized. This research based on a big bus with traditional electrical device system; designed whole vehicle network specific to requirements of IEEDS; established network protocol and does simulation and optimization; developed Invariant Harness system; built a full online intelligent fault diagnosis system; finally implemented and verified the system on the real bus.Firstly, network structure and communication protocol of IEEDS are designed and optimized. Based on the intelligence function design of Intelligent Electrical and Electronic Device (IEED), this research constructs CAN/LIN network to connect all IEEDs, and designs bus topology and network layout by the distribution of all devices, so that the system architecture is planned. System network protocol is designed according to J1939 and LIN 2.0 standards, and the system network model is built with VNA to simulate the protocol and verify the schedulability of network message and the timeliness of signals, based on which the timing parameters of the protocol is then optimized.Secondly, a set of Invariant Harness is designed and developed for the transmission of signal and power, according to network design of IEEDS and bus frame structure. With unified electric supply mechanism and interface, Invariant Harness is a standardized vehicle harness system, including three types of wire harnesses: CAN network harness, LIN network harness and power harness. The technical parameters of harness are determined by the network division of the whole bus and the power of each device, the harness 3D spatial layout is designed based on the bus 3D model, and the Invariant Harness is eventually implemented on the bus.Thirdly, a vehicle fault diagnosis system is built based on IEEDS' fault analysis to implement diagnosis on individual IEED units, wire harness and system coordination. The main program of diagnosis system is implemented on the CAN node named Virtual Terminal. By transmitting Diagnosis Request proactively or monitoring CAN messages passively, the diagnosis program collects self-diagnosis and status messages transmitted by IEEDs, based on what a system-level analysis and judgment can be made and the driver would be reminded for any detected fault by a human-machine interface.Based on previous research, IEEDS is implemented on the bus and a series of tests are designed to verify feasibility and reliability of the network design, including network protocol, Invariant Harness and diagnosis system.