The morphological undecimated wavelet decomposition - Discrete cosine transform composite spectrum fusion algorithm and its application on hydraulic pumps

Degradation feature extraction of hydraulic pumps is a key step of the condition-based maintenance. In this paper, a novel method based on MUWD-DCS fusion algorithm is proposed. In order to decrease noises and disturbances, the method for obtaining detail components by the Morphological Undecimated Wavelet Decomposition (MUWD) with the selected parameters is presented firstly. Multi-channel vibration signals are proposed by the MUWD and the detail components containing sensitive information are achieved. Furthermore, on the basement of the earlier Composite Spectrum (CS), the DCS fusion algorithm is proposed to make fusion of the obtained detail components for improving the feature performance. The DCS entropy is extracted to be the degradation feature. Analysis of application on the hydraulic pump degradation experiment demonstrates that the proposed algorithm is feasible and it is effective to reveal the performance degradation of the hydraulic pump.