The Application of Vibration Signal Multi-fractal in Fault Diagnosis

Condition monitoring of machines through the analysis of their vibrations has been recognized to be a difficult issue, essentially because of the strong nonlinearity of the vibration signals. In this paper, vibration signal multifractal method was researched. multifractal on time-frequency domain was an energy fractal method and the signal feature extraction was based on the analysis of its energy distributing. The method analyzed signal on time-frequency domain to characterize the distributing of its frequency or energy, and the signal´s feature was extracted by fractal dimension. After the signal was changed to time-frequency domain by Hilbert-Huang transform, general dimension Dq would be calculated from the signal in time-frequency domain by least square method. In the end, examples of emulator and practical application proved that this integrated method was feasible.