JIANG Xingxing1,WU Nan1,SHI Juanjuan1,SHEN Changqing1,LI Chuan2,ZHU Zhongkui1
JOURNAL OF VIBRATION AND SHOCK. 2018, 37(20): 166-172.
One of the key steps for rotating equipment fault diagnosis under variable speed condition is to acquire the accurate shaft instantaneous frequency (IF).The most effective way to realize it is based upon the Time-frequency distribution (TFR) analysis.However, its effectiveness is often undermined by the TFR’s poor energy concentration and weak shaft IF-related signal segmentations caused by strong background noise and interferences.A speed estimation method based on the ridge enhancement and feature fusion was, therefore, proposed in this paper.The TF ridge candidates were enhanced firstly by the amplitude sum-square method, and then the TF ridge candidates in lower band and the resonance band were searched, respectively.The fusion criterion based on probability distribution and local fluctuation was, finally, established to acquire the accurate estimation of shaft IF ridge.Compared with conventional methods, the proposed method yields more accurate IF approximation results and is less sensitive to noise.The experiment results validate the effectiveness of the proposed method for shaft IF estimation.