| Due to its convenient operation and comfort,automatic transmission has been widely used in various types of automobiles.Automatic transmission(AT)is one of the most widely used automatic transmissions and is favored by many vehicle manufacturers.However,the high integration of the automatic transmission structure and the diversity of the fields involved make it difficult to diagnose faults.Fault diagnosis of mechanical and hydraulic systems is more difficult and fault samples are difficult to obtain.Fault simulation technology can solve this problem well.This article focuses on the mechanical and hydraulic systems of automatic transmissions and uses simulation models to study their failures.In this paper,taking the A340 E automatic transmission as an example,by analyzing the structure of AT to obtain a logical diagram of the mechanical and hydraulic system,using FMEA(Failure Mode and Effect Analysis)to analyze main components,and then establish logical relationship between failure modes and fault features.Then,AMESim,a kind of system modeling simulation software is used to establish a united simulation model of automatic transmission mechanical system and 1-2 gear shift hydraulic system.The validity of the model was verified by VV&A(Verification,Validation and Accreditation).Next,based on the theoretical basis of fault injection,the mechanical and hydraulic fault injection methods for the common fault components of automatic transmission are studied.Taking the example of shift valve,solenoid valve and brake,the fault is simulated and analyzed.Finally,Through the analysis of multiple characteristic curves and data,the relationship between failure modes and fault features are obtained,and the three modes of shift valves are identified using a SVM(support vector machine).The results show that simulation data is valid.This paper establishes a united simulation model of mechanical and hydraulic systems of automatic transmissions and provides a new example for the establishment of a multi-system simulation model.Failures injection technology is used to study mechanical and hydraulic system failures.The experimental results show that this method can easily obtain failure data.In the case of fewer failure modes,the failure mode identification method based on SVM can more accurately confirm the relationship between the failure mode and the failure characteristics,so the failure data sample can provide good raw data for the failure diagnosis system. |
