An Improved Fuzzy Fault Diagnosis Method for Complex System

Based on extension set theory, an improved fuzzy fault diagnosis method was presented. The structure of fault model expression was built which contains the classic field and admittable field of fault symptoms. The structure described the fault state was established which consists of the denotation of the fault state, the symptoms and the corresponding values. Normalized membership function and membership degree of a symptom were introduced to evaluate the possibility of the fault quantitatively. The biggest dependence rule was established to diagnose the fault. The multiple faults rule, which contains the difference field and the recognition field, was established to diagnose the multiple faults. The diagnosis example was taken to validate the method. The diagnosed result shows that the method presented can effectively be used to diagnose the complex machinery systems