The Research And Application Of CAN UDS

With the growing number of automotive electronic control unit (ECU),the load of network bus is increasing.When a failure occurs,CAN UDS (Unified Diagnostic Services)can easily determine the malfunction and find the failures.CAN UDS has been used extensively.Based on lots of domestic and foreign analysis data reading.Firstly,this dissertation introduces the characteristics of the CAN bus and describes its development status.Then,it detail analysis the layered structure of CAN UDS,including the network layer(ISO15765-2),the session layer(ISO15765-3),the application layer (ISO15765-3/ISO14229-1) and communication interface.CAN UDS uses the way of combination agreement,because of its advantages in the transmission mechanism,time control,error detection,and so on.Currently,it widely used in the automotive diagnostic network.Its communication time control of the network layer is strict,More comprehensive diagnostic services is provided in the application layer.In order to reduce the network layer transmission time,how to reasonably set up the parameters and implement different diagnoses,as per different requirements,is still pending to research.Thirdly,contrast with the traditional vehicle diagnostic protocol KWP2000protocol.CAN UDS show a strong advantage in the field of automotive network diagnostics.In the timing mechanism of the network layer,packet transmission loss a lot of time.In this paper, the M/M/1queuing model is used,which optimizes the communication process packets multi-frame transmission average wait time at the network layer.Through the simulation in MATLAB in stateflow tools,it prove the feasibility of improved STmin parameters.Finally, the dissertation introduces the seat ECU diagnosis system,which prove the reliability of the diagnostic system of the seat controllers through CANMonitor software debugging.