Energy operator demodulating of signal's resonance components for the compound fault diagnosis of gearbox.

When the gears fault and the bearings fault in a gearbox occur at the same time, the symptoms of the weak fault usually is submerged in the strong fault symptoms. Therefore, it is difficult to detect the weak fault directly through the demodulating analysis of the gearbox vibration signals. For that problem, a method of compound fault diagnosis of gearbox is proposed based on the energy operator demodulating of signal's resonance components. In this method, the gearbox vibration signal is decomposed using resonance-based sparse signal decomposition. The higher-resonance component (the amplitude modulation component) indicates the gear's fault and the lower-resonance component (the impulse component) indicates the bearing's fault to separate them from each other. The separated amplitude modulation component and the impulse component are then analyzed by energy operator demodulating, and each of their instantaneous amplitude can be calculated. According to the spectrum of the instantaneous amplitude, the gear's fault and the bearing's fault can be diagnosed respectively, so the compound fault of a gearbox can be diagnosed. Some simulation and illustrative examples proved the effectiveness of the method. [ABSTRACT FROM AUTHOR]