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The the HHT analysis and application of mechanical vibration signal

Author: DingRui
Tutor: LiuZengLi
School: Kunming University of Science and Technology
Course: Communication and Information System
Keywords: Non-stationary signals EMD decomposition Denoising Line spectrum extraction Time-frequency analysis
CLC: TH113.1
Type: Master's thesis
Year: 2010
Downloads: 204
Quote: 0
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Abstract


Hilbert - Huang transform (HHT) becomes non-stationary signals as an analysis of a new technology has become a research focus in the field of modern signal processing. By empirical mode decomposition (EMD) and the Hilbert transform of two parts, which EMD is the core part. EMD complex signal is decomposed into a finite number of intrinsic mode function (IMF) by the Hilbert transform to obtain the instantaneous frequency and related concepts. With the advancement of technology and the development of social, HHT technology is increasingly used in underwater moving target radiated noise, blasting vibration, earthquake, medical signal and mechanical equipment fault diagnosis, and many other important research value. The main contents of this paper include the following aspects: First, expounded the basic theory and concept of HHT, EMD decomposition algorithm HHT time frequency spectrum, the physical meaning of the HHT energy spectrum and marginal spectrum, and on this basis to the impact to the EMD of accuracy of the two main factors - noise due to modal aliasing and edge effect. Second, with respect to the traditional Fourier denoising, wavelet denoising appear along with HHT appears the EMD denoising methods, this paper designed a new EMD combined with wavelet denoising method, applied to the bearing signal background noise denoising. Select the white noise and Rayleigh distribution noise as the processing object, by the signal-to-noise ratio and correlation coefficient of these two indicators show that the method has a good effect to remove background noise. Again to introduce a variety of classic power spectrum estimation method for spectrum analysis and extraction of the signal line in the traditional power spectrum estimation, this paper design EMD and classic power spectrum estimation method of combining the analysis and extraction of line spectrum and the simulation signal and the actual bearing data processing, thus indicating that the method has a better frequency resolution, while bearing fault detection signal by setting the feature quantity. Finally, through theoretical analysis and simulation, from both the time and frequency HHT time frequency spectrum and FFT spectrum STFT spectrum, Wigner-Ville distribution and morlet the small spectral comparison and combination of HHT three-dimensional spectrum and marginal spectrum analysis , that the HHT analysis method has higher time frequency aggregation, inhibition of the cross-interference term, have a good time-frequency resolution, and proven again by applied to mutation signal, which proposed the method is equally applicable to the detection of the fault signal.

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CLC: > Industrial Technology > Machinery and Instrument Industry > Mechanics (mechanical design of the basic theory ) > Mechanical kinetics > Mechanical vibration
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