Adaptive optimal envelope demodulation method

An envelope demodulation and self-adaptive technology, applied in the direction of mechanical bearing testing, etc., can solve problems such as constraints, affecting spectral kurtosis, affecting signal filtering effect, etc., to overcome easy failure, improve application effect, and improve robustness. Effect

Inactive Publication Date: 2015-07-22
NAVAL UNIV OF ENG PLA
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Problems solved by technology

The traditional kurtosis map has the following two types of defects: 1) The frequency characteristics of the filters used in the traditional kurtosis map are not ideal, which will inevitably affect the filtering effect of the signal, and thus affect the estimation of the spectral kurtosis. Therefore, the ability of the kurtosis map to detect the weak transient fault impact hidden in the strong background noise is restricted, which limits the application effect of the kurtosis map; 2) the traditional kurtosis map only extracts the optimal frequency band according to the spectral kurtosis

Method used

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Examples

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Embodiment 1

[0048] This example uses the bearing outer ring fault signal to verify as figure 1 The correctness of the method of the present invention for diagnosing rolling bearing faults is as follows:

[0049] The first step is to collect the vibration acceleration signal of the faulty bearing. figure 2 The time-domain waveform and frequency spectrum of the vibration acceleration of a 6205-2RS deep groove ball bearing with an outer ring failure. The vibration acceleration signal is measured by an acceleration sensor mounted on the bearing seat. The geometric parameters of the bearing are: pitch diameter 39.04mm, rolling element diameter 7.94mm, number of rolling elements 9, and contact angle 0°. In the experiment, the rotation frequency of the shaft is set to 29 Hz, the sampling frequency is 12 kHz, and the sampling length is 2048 points. Based on the above parameters, the characteristic frequency of the bearing outer ring fault is calculated to be 103 Hz.

[0050] The second step is to p...

Embodiment 2

[0067] This example uses the bearing inner ring fault signal to verify as figure 1 The correctness of the method of the present invention for diagnosing rolling bearing faults is as follows:

[0068] The first step is to collect the vibration acceleration signal of the faulty bearing, such as Picture 10 Shown. Picture 10 It is a time-domain waveform diagram of the vibration acceleration of a 6205-2RS deep groove ball bearing with inner ring failure. The vibration acceleration signal is measured by an acceleration sensor mounted on the bearing seat. The geometric parameters of the bearing are: pitch diameter 39.04mm, rolling element diameter 7.94mm, number of rolling elements 9, and contact angle 0°. In the experiment, the rotation frequency of the shaft is set to 29 Hz, the sampling frequency is 48 kHz, and the sampling length is 8192 points. According to the above parameters, the characteristic frequency of the bearing inner ring fault is 155Hz.

[0069] The second step is to ...

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Abstract

The invention discloses an adaptive optimal envelope demodulation method, which is characterized by comprising the following steps: bearing fault vibration acceleration signals are acquired; improved harmonic wavelet packet transform is carried out on the signals; an improved harmonic wavelet packet kurtosis graph fused with energy indexes is drawn; the optimal frequency band is extracted according to the maximal spectral kurtosis in the kurtosis graph; modular operation is carried out on wavelet coefficients of the optimal frequency band to obtain an envelope, and FFT transform is carried out on the envelope to obtain an envelope spectrum; refinement is carried out on the envelope spectrum, and a fault type of the bearing is determined in the refined envelope spectrum. Two aspects of the prior art are improved: on one hand, conventional harmonic wavelet packet transform is firstly improved, the frequency band can be divided more precisely, the improved harmonic wavelet packet transform is combined with the kurtosis graph, the improved harmonic wavelet packet kurtosis graph is formed, the ability of detecting weak transient fault impact by the kurtosis graph is enhanced, and the application effects are improved; and on the other hand, energy information is fused in the kurtosis graph, and robustness of the kurtosis graph is improved.

Description

Technical field [0001] The invention belongs to the field of fault diagnosis of rotating machinery, and particularly relates to an adaptive optimal envelope demodulation method, which is very suitable for feature extraction and fault diagnosis of rolling bearings. Background technique [0002] Rolling bearings are one of the core components of the mechanical transmission system of weapon equipment such as artillery, tanks, helicopters, and naval vessels. Its performance directly affects the reliability and safety of weapon equipment. Due to long-term continuous work under high load, high speed, high impact and variable working conditions, rolling bearings are extremely prone to damage and failure. Therefore, studying the feature extraction and fault diagnosis methods of rolling bearings, effectively extracting fault feature information and accurately identifying its current state, is of great significance for avoiding major accidents and maintaining the integrity of weapons and e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01M13/04
Inventor 田福庆罗荣刘方潘林豪
Owner NAVAL UNIV OF ENG PLA
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