航空发动机快变信号的匹配同步压缩变换研究

Feature extraction of aero-engine's vibration signals with fast time-varying instantaneous frequency (IF) plays an important role in health monitoring and fault diagnosis for aero-engines. According to the nonlinear frequency-modulated (FM) property of the aero-engine's vibration signals, a time-frequency analysis (TFA) method called matching synchrosqueezing transform (MSST) is introduced to achieve a highly concentrated TF representation comparable to the standard time-frequency reassignment methods (STFRM), even for signals with fast varying IF; furthermore, MSST retains the reconstruction benefit of synchrosqueezing transform (SST). MSST captures the philosophy of STFRM to simultaneously consider time and frequency variables, and incorporates three estimators (i.e., the IF estimator, the group delay estimator, and a chirp-rate estimator) into a comprehensive and accurate IF estimator. The effectiveness of MSST is verified by experimental and practical applications. The results of aero-engine engineering applications show that the feature of the fast varying IF caused by the rub-impact fault in an aero-engine rotor system can be effectively extracted and thus the rub-impact fault is diagnosed.