The Eps System Self-Diagnosis Research For Low-Emisson Vehicles

Along with the computer and Electronic control technology rapid development in recent years, the auto electric Power Steering technology (EPS) has been researched by many car companies and universities; This article designed a system of self-diagnosis in view of the application in EPS control system of low-emission vehicles.The EPS self-diagnosis function can online monitor, diagnosis and timely-effective handle the eps faults. Therefore, it can reduce the risk of the vehicle when EPS system is out of order.this paper analyzed the development of domestic and foreign technology. Then it showed the self-diagnosis technology plays a significant role in the whole control system. Fault tree analysis was used to analyze problems in view of low-emission cars, including all kinds of possible failure and the cause of the failure, including the torque sensor, vehicle battery, the speed and the engine speed sensors and so on. Because there were many fault points, the fault points was classified and the fault diagnosis system fault table was summarized.when the EPS faults occur,due to the different current treatments will lead to different effects for the car, the faults was divided into two different categories. And according to the different effects of the faults, the self-diagnosis flow chart and safety protection strategy were designed by utilizing different failure treatment methods.besides,in order to ensure stable and reliable operation of the system safety, the toolbox of matlab/simulink was used to research the signal processing technology of fault diagnosis. Therefore, the technology of filter process and some measures of prevent signal interference was applied to the system safety strategy for avoiding the eps faults and take this safety measures is necessary; the current limit protection function was designed, it can effectively prevent the control system damage for high current in the current limit protection control program execution stage.in the above research foundation, the chart of fault diagnosis was given by Using the C language program of the single chip computer combined with the anti-interference measures and necessary measures to protect the safety of hardware. This design, based on the low-emission vehicle control system EPS, can realize the fault information identification, alarm and cut off the error current in time and light the fault warning light. In the car test, desirable results were gained. It demonstrated that the eps system fault self-diagnosis is effective.