| With the wide application of the electronic control units(ECU) in car, themethod of using the on board diagnostic(OBD) system to diagnose ECU is themainstream choice for automotive fault diagnosis. Used with the OBD system,automotive fault diagnostic instrument for ECU is used as offline devicewhich can improve the reliability of automotive diagnosis to read the ECU'sdiagnostic results from OBD system. At present, the fault diagnosticinstruments used by the mainstream car manufactures are applicable within alimited diagnostic object scope and they don't have versatility. Although somediagnostic equipment manufacturers committed to research the universalautomotive fault diagnostic instruments, and the diagnostic object scope isexpanded, but the update of hardware, software and diagnostic functions isvery complex, so they don't realize the true versatility. On the other hand, theOBD system commonly used board diagnostic communication standard toachieve diagnosis for combining the diagnosis and vehicle networks. ISO142-30and ISO9141are the board diagnostic communication standards which arecommonly used in internal based on K bus. With the wide application of CANin car, if OBD system continues to use ISO14230and ISO9141, diagnosticsystem will be independent of the CAN, the internal network will be verycomplex, and the system costs will be greatly increased. Therefore using thediagnostic communication standard based on CAN bus in OBD system is thedevelopment trend of automotive diagnosis. The research and exploitation ofuniversal automotive fault diagnostic instrument based on CAN bus isaccordance with the development trend of internal automotive fault diagnosis,and it has important value and significance for improving the accuracy andreliability of domestic automotive fault diagnosis.Contrary to the universal goals of diagnostic instrument, the versatilityof fault diagnostic instrument and automotive fault diagnostic technologybased on CAN bus are researched in this thesis. Meanwhile a universal vehiclefault diagnostic instrument for ECU based on CAN bus is designed in thisthesis. The main contributions of the dissertation include the following: (1)The research of background and significance are explained. Thedomestic and international status quo of the automotive fault diagnostic studyare introduced. The purpose of dissertation is analyzed. The main researchworks and content aimed at the dissertation are addressed.(2)To the basis of UDS diagnostic standard ISO15765, the architecture ofthe diagnostic system is addressed. This architecture is researched fromapplication layer, network layer, data link layer and physical layer. Then theXML-based theory and XML-related technologies are researched and it'sanalysed. The system versatility of diagnostic system is addressed by theXML configuration files.(3)The overall design proposal of system is designed based on SOPC.Meanwhile the parts of sytem are detaily analysed and introduced.(4)From the system hardware, SOPC system hardware, the managementand configuration of automotive information and diagnostic information, thedesign of the universal automotive fault diagnostic instrument based on CANbus is detaily introduced in this thesis.To validate the availability and feasibility of the designed system in thedissertation, the simulation test platform based on the test board and theactual automotive test platform based on battery management system are setup. The system tests based on the two platforms above are carried out. Thesystem function test, the diagnostic accuracy test, the speed test of systemoperation and response are included in the test content. By the test andresearch of test cases and results, the feasibility and effectiveness of systemdiagnostic, system function, system versatility are validated. Meanwhile, inthis thesis, the feasibility and availability of the system proprosal and designare proved. The universal program of the automotive fault diagnosticinstrument based on CAN bus is designed and resolved. |
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