The Comparison of Vibration Signals' Time-frequency Analysis Between EMD-based HT and Winger Distribution Method In Rotating Machinery

The method of empirical mode decomposition (EMD) based Hilbert Transformation(HT) is that, first, separate the series data to components with different time scale, say, intrinsic mode function (IMF), using EMD, then apply the Hilbert transformation to every IMFs. The result is the time-frequency spectrum of the data. The method and algorithm was explained in detail. Emulation and oil film whirling vibration signals were analyzed using the method. After applied Hilbert transformation to the signals' IMFs, the time-frequency spectrums were obtained. The Winger Distribution analysis method was applied to the signals also. Compared the two time-frequency method, The EMD-based HT timefrequency analysis of the vibration signal is more accurate than the Winger distribution's for represents the aptitudes and frequencies changes following time. The conclusion was deduced that the EMD-based HT timefrequency analysis method is better than the Winger distribution's in the field of vibration signals' processing in rotating machinery.