Sensor-Less Jam Fault Detection of Electro-hydraulic Executive Device under Interval-Valued Intuitionistic Fuzzy Circumstance

This paper presents a novel jam fault diagnosis method for electro-hydraulic executive device of steam turbine based on electro-reflection and interval-valued intuitionistic fuzzy sets (IVIFSs) theory. Theoretical analysis and modeling research are conducted to reveal the relationship between jam fault and the peak-to-peak value of the oscillation current (PVOC). Then we constructed a proportional valve load simulation device to carry out experimental and model based research. The results show that the variation of PVOC changes non-monotonically when jam fault occurs and thus has a characteristic of uncertain and interval-valued. To overcome the problem, the concept of IVIFS is introduced, and the distance between two IVIFSs is defined. Then, the similarity degree between the detected variation of PVOC and the knowledge of jam fault is evaluated. The level of jam fault is determined according to the similarity degree.