Matching Demodulation Transform With Application to Feature Extraction of Rotor Rub-Impact Fault

摘要

Conventional time–frequency analysis (TFA) methods have played an important role in characterizing the TF pattern of nonstationary signals. In this paper, a new TFA algorithm, called matching demodulation transform (MDT), is introduced to extract the highly oscillatory frequency modulation (FM) feature of rotor rub-impact fault. When a rub-impact fault occurs in the rotor system, vibration signals will present the FM feature because of the periodic rub-impact between the stator and the rotor. Through a partial demodulation and stepwise refinement procedure, the highly oscillatory FM feature is represented with satisfactory energy concentration in the time–frequency plane. The validity and practical utility of the MDT is then demonstrated on an experimental rotor system and a practical heavy oil catalytic cracking machine set with a rotor rub-impact fault. The analysis results show that the MDT is powerful in the analysis of FM signals and is an effective tool for the feature extraction of rub-impact faults.