Research Of Electric Vehicles Can Network Testing And Diagnostic Technology

With the gradual improvement of EV performance,the corresponding control system becomes complex and the extent of information interaction between control units subsystems intensifies.The complicacy of designing and testing CAN network,the main information interaction way of control units in current EV,surges with those changes.Focused on CAN network of EV,technologies and tasks to test CAN network are deeply researched.In accordance with different stages in development,simulating test platform was designed based on CANoe to assist network development and improve efficiency.In the stage of system integration,for rapid location of malfunctions in CAN based electric control system during the real vehicle debugging process,malfunction tree and data flow analysis were adopted to develop malfunction diagnosis system on the basis of CAN network.In the beginning of this paper,the development process of CAN bus was introduced.Analysis of V development mode was highlighted,development strategy in combination of designing and verification was introduced,and main tasks of CAN network testing was identified.CAN network testing technology was researched according to testing tasks.The V type CAN network development mode was adopted and test platforms were devised in different development stages on the basis of CANoe through analysis and summary of specific testing measures.In the stage of designing application layer,bus simulation model was built to verify the validity of protocol.In the stage of designing node ECU,remnant bus test platform was built to test communication function and control strategy.In the entity integration stage,on-line monitoring platform was established to grasp the state of vehicle network.As an extension of CAN network development,basic malfunction diagnosis methods were explored in the vehicle network integration stage.Malfunction tree and data flow analysis were chosen as the diagnosis scheme by researching malfunction diagnosis technologies.Typical malfunctions that are common in vehicle tests were summarized,diagnosis strategy of typical malfunction was determined by building malfunction model of typical malfunction.Malfunction diagnosis system was devised via CANoe and STATEFLOW by adopting CAN data analysis.The devised platform was applied to practical development process of CAN network.Protocol of application layer were validated via simulation,communication and control strategy of node ECU were verified through remnant bus test platform,and on-line monitoring of vehicle network was finished by on-line testing platform.In vehicle network debugging,typical malfunctions can be automatically diagnosed.The results of tests and diagnosis were compared with the real situation and proved accuracy.The test platform and malfunction diagnosis system applied well in the development process of CAN network,which immensely simplified development and improved efficiency.