Research And Application On Fuzzy Diagnosis Method For Reciprocating Compressor

Because of the reciprocating compressor's complex structure, multi-stimulations, chaos and coupling of the signals, diagnosis results are not often up to much by single-method. In many situations, fault information is not defined clearly, that causes the fuzzy states. So definite expression is difficult to get through conventional mathematics methods. The resolution is applying fuzzy mathematics to fault diagnosis fields. Fault symptom is described by membership function, and then the judgments can be got by calculation. This is called fuzzy diagnosis method.Firstly, the structure, work principles and fault forms of reciprocating compressor are introduced particularly in this paper. Secondly, the fault mechanisms of valves and piston subassemblies are analyzed from thermodynamics and vibration methods. Thirdly, according to different fault forms, qualifications are defined correspondingly. At last the fault reasons are analyzed through fuzzy judgment and max membership function. Because all of the fault reasons and chaos conditions are considered, a better diagnostic result is achieved.The difficulty of fuzzy diagnostic method that is discussed above is the foundation of fuzzy matrix, because it needs the experience of expert, moreover, it will affect the results greatly. Then a new diagnostic method based on fuzzy neural network (FNN) is mentioned in this paper. Nerve network can self-study and fuzzy logic corresponds to thinking, so FNN is a new direction of intelligent diagnosis fields. By MATLAB tool, the ANFIS model which data has been disposed by FCM is designed, and it attains a higher precision after training.There are two methods for signal collection: online and offline. For the latter method, portable data acquisition instrument is often used. Because of cheapness and convenience, it is widely applicable in condition monitoring. But portable instruments usually have a disadvantage: small memory capability. This paper applies Compact Flash card to the data collector instrument successfully, which enlarge the memory capability, and the document management is achieved. At present, this instrument has been used in fact reliably.