Development And Design Of Automated Vehicle Diagnostic Test System Based On VT System

With the development of automotive vehicle network,especially CAN bus communication technology was widely used in the field of automotive electronics,the automotive diagnostic protocol developed from the ISO14230 standard based on K line to ISO15765 standard based on CAN bus.The diagnostic test is aimed to verify whether the diagnostic function of the vehicle ECU(electronic control unit)meets the standard diagnostic protocol and whether the DTC(diagnostic trouble code)generation and recovery mechanism meets thestandard requirement.In order to meet the requirements of current automotive diagnostic tests for test efficiency and test versatility,an automated diagnostic test system is designed for DTC testing.The main contents of this paper are as follows:The contents of the protocol of the high-speed CAN bus and the contents of the unified diagnostic service(UDS)protocol are analyzed.The requirements of the DTC test and the diagnostic protocol test are analyzed to determine the test range of the diagnostic automation test system,including all DTC tests other than the internal fault such as the ECU's own storage error item.Then the current DTC test deficiencies arepointed out,thus setting the direction and goal for the system design.The HIL hardware in loop system added to the electrical fault code test,and the network simulation model added to the network fault code test are determined.The overall architecture of the DTC test system is designed,and the system is developed by using VT System as the hardware foundation and CANoe as the core of the software.According to ECU working principle and pin definition,VT module resources areallocatedfor theECU to be tested,and full network is simulated based on CANoe,so that to minimize the impact of the current test DTC processing mechanismto other DTC processing mechanisms during the test,the accuracy of the test results are ensured.Versatile DTC test logic isdesigned,the network fault code test script is wrote by using the variational processing parameters method,avoiding the individuality of the test,obviously improving test efficiency and versatility.A diagnostic DTC automated test system is set up,the test results and efficiency are verified through the actual test.Contrasting with manual test,the accuracy of the automated test results is validatedand the test time is reducedmore than half of the manual test.Finally,the hardware maintenance related work is put forward,mainly including the calibration of VT System.And the contents of the system expansion development are briefly introduced,mainly including the diagnosis protocol test.