Rub-Impact Fault Diagnosis of a Coal Crusher Machine by Using Ensemble Patch Transformation and Empirical Mode Decomposition

In this paper, a newly developed signal decomposition technique called Ensemble Patch Transformation (EPT) is used for the first time to identify mechanical faults of a hammer type coal crusher machine. Rub-impact faults of a rotary machine result in amplitude modulation of the vibration signal. In this scenario, mode decomposition of a complex signal is essential when the signal is a combination (either convolutive or additive) of many simpler signals. EPT is a newly developed multi-resolution signal analysis method inspired by multi-scale concept of scale-space theory. As Empirical Mode Decomposition (EMD) method can decompose a complex signal into a number of simpler signals called intrinsic mode functions (IMF); the EPT process can also decompose a complex signal into a main frequency component (FC) and a residual signal. The residual signal again can be decomposed into a FC component and residual component and this process can be repeated for a number of times. Initially, the performance of the EPT is investigated on a simulated signal. Then, the same method is applied to find out rub-impact fault of a hammer type coal crusher machine in a steel plant. Finally, the superiority of the EPT based method is demonstrated during extracting multiple signals with comparison to the EMD based method.