State recognition based on wavelet packet norm entropy for aircraft hydraulic pump

This paper presents a new state recognition method based on wavelet packet norm entropy (WPNE). Directing to the complicated operational condition of aircraft hydraulic pump, the wavelet packet denoising and Hilbert envelope demodulation are adopted to remove the disturbance influence of radial ad axial acceleration signal. In order to highlights the failure features in full band, the norm entropy is instead of the Shannon entropy to carry out the state recognition. Application indicates that WPNE can give apparent degradation trends under the terrible environment and realize the state recognition with high precision.