scholarly journals Compound Fault Diagnosis of Bearings Using an Improved Spectral Kurtosis by MCDK

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Shuting Wan ◽  
Xiong Zhang ◽  
Longjiang Dou
Keyword(s):  
Resonant Frequency ◽  
Frequency Band ◽  
Practical Applications ◽  
Noise Interference ◽  
Spectral Kurtosis ◽  
Modified Method ◽  
Weak Fault ◽  
Fault Information ◽  
Demodulation Method ◽  
Fault Characteristic

The fast spectrum kurtosis (FSK) algorithm can adaptively identify and select the resonant frequency band and extract the fault feature by the envelope demodulation method. However, in practical applications, the fault source may be located in different resonant frequency bands; plus in noise interference, the weak side of the compound fault is not easy to be identified by the FSK. In order to improve the accuracy of fast spectral kurtosis analysis method, a modified method based on maximum correlation kurtosis deconvolution (MCKD) is proposed. According to the possible fault characteristic frequencies, the period of MCKD is calculated, and the appropriate filter length is selected to filter the original compound fault signal. In this way, the compound fault located in different resonance bands is separated. Then, the signal after MCKD filtering is analyzed by FSK. Through the simulation and experimental analysis, the MCKD can separate the compound fault information in different frequency band and eliminate the noise interference; the FSK can accurately identify the resonance frequency and identify the weak fault characteristics of compound fault.

scholarly journals Compound Faults Feature Extraction for Rolling Bearings Based on Parallel Dual-Q-Factors and the Improved Maximum Correlated Kurtosis Deconvolution

2019 ◽  
Vol 9 (8) ◽  
pp. 1681 ◽  
Author(s):  
Cui ◽  
Du ◽  
Yang ◽  
Xu ◽  
Song
Keyword(s):  
Rolling Bearing ◽  
Rolling Bearings ◽  
Outer Race ◽  
Spectral Kurtosis ◽  
Bearing Fault Diagnosis ◽  
Fault Features ◽  
Q Factors ◽  
The Impact ◽  
Fault Information ◽  
Fault Characteristic

Vibration analysis is one of the main effective ways for rolling bearing fault diagnosis, and achallenge is how to accurately separate the inner and outer race fault features from noisy compoundfaults signals. Therefore, a novel compound fault separation algorithm based on parallel dual-Qfactorsand improved maximum correlation kurtosis deconvolution (IMCKD) is proposed. First, thecompound fault signal is sparse-decomposed by the parallel dual-Q-factor, and the low-resonancecomponents of the signal (compound fault impact component and small amount of noise) are obtained,but it can only highlight the impact of compound faults, and failed to separate the inner and outerrace compound fault signal. Then, the MCKD is improved (IMCKD) by optimizing the selection ofparameters (the shift order M and the filter length L) based on the iterative calculation method withthe Teager envelope spectral kurtosis (TEK) index. Finally, after the composite fault signal is filteredand de-noised by the proposed method, the inner and outer race fault signals are obtained respectively.The fault characteristic frequency is consistent with the theoretical calculation value. The results showthat the proposed method can efficiently separate the mixed fault information and avoid the mutualinterference between the components of the compound fault.

scholarly journals Rolling Bearing Fault Feature Extraction Based on Adaptive Tunable Q-Factor Wavelet Transform and Spectral Kurtosis

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Jianlong Zhao ◽  
Yongchao Zhang ◽  
Qingguang Chen
Keyword(s):  
Feature Extraction ◽  
Wavelet Transform ◽  
Frequency Band ◽  
Rolling Bearing ◽  
Band Pass Filter ◽  
Q Factor ◽  
Bearing Fault ◽  
Spectral Kurtosis ◽  
Manual Selection ◽  
Weak Fault

The fault feature of the rolling bearing is difficult to extract when weak fault occurs and interference exists. The tunable Q-factor wavelet transform (TQWT) can effectively extract the weak fault characteristic of the rolling bearing, but the manual selection of the Q-factor affects the decomposition result and only using TQWT presents interference. Aiming at the above problems, an adaptive tunable Q-factor wavelet transform (ATQWT) and spectral kurtosis (SK) method is proposed in this paper. Firstly, the method applies particle swarm optimization (PSO) to seek the optimized Q-factor for avoiding manual selection, which uses the kurtosis value of the transient impact component as the particle fitness function. The rolling bearing fault signal is decomposed into continuous oscillation component and transient impact component containing fault feature by the optimized Q-factor. Then, due to the presence of interference in the decomposition result of ATQWT, the SK analysis of the transient impact component is used to determine the frequency band of periodic impact component characterizing fault feature by fast kurtogram. Finally, the band-pass filter established through the above frequency band is employed to filter the interference in the transient impact component. Simulation and experimental results indicate that the ATQWT can highlight the periodic impact component characterizing rolling bearing fault feature, and the SK can filter interference in the transient impact component, which improves feature extraction effect and has great significance to enhance fault diagnosis accuracy of the rolling bearing. Compared with EEMD-TQWT and TQWT-SK, the fault feature extracted by the proposed method is prominent and effective.

scholarly journals A 1.5D Spectral Kurtosis-Guided TQWT Method and Its Application in Bearing Fault Detection

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiong Zhang ◽  
Ming Zhang ◽  
Shuting Wan ◽  
Rujiang Hao ◽  
Yuling He ◽  
...  
Keyword(s):  
Frequency Band ◽  
Signal To Noise Ratio ◽  
Signal Transmission ◽  
Low Frequency ◽  
Signal Frequency ◽  
Bearing Fault ◽  
Spectral Kurtosis ◽  
Fault State ◽  
Periodic Impulse ◽  
Fault Characteristic

Bearings are the key parts of rotating machinery, and their operation status is related to the operation safety of the whole equipment. Vibration signals often contain periodic impulse components which can reflect the fault state of bearings. However, due to the interference of signal transmission path and the influence of operating environment noise, the periodic impulse components in the signal are often submerged by the nonperiodic transient impulse components, modulation harmonic components, and noise components. Therefore, the core problem of bearing fault diagnosis theory is used to accurately extract the frequency band of bearing fault state information and suppress the frequency band of interference information. In this paper, the signal is processed by the tunable Q-factor wavelet transform (TQWT), the midfrequency band of the signal is tightly divided by selecting different Q-values, and the 1.5D spectral kurtosis defined in frequency domain is used to select the optimal subband. Simulated analysis shows that this method can avoid low-frequency harmonic interference, nonperiodic transient impulse components, and strong noise components in the time domain. Therefore, it can effectively realize the selection of the subbands of periodic impulse components and effectively extract fault feature information. Through experimental signal analysis, TQWT has good sparsity decomposition characteristics and can reasonably divide the signal frequency band, so as to separate the useful fault characteristic frequency band and interference frequency band. At the same time, compared with the kurtosis index, 1.5D spectral kurtosis has better robustness and resolution for low signal-to-noise ratio signals, which can achieve the purpose of fault characteristic band extraction.

Rolling element bearing weak fault diagnosis based on optimal wavelet scale cyclic frequency extraction

2018 ◽  
Vol 232 (7) ◽  
pp. 895-908 ◽  
Author(s):  
Rui Yang ◽  
Hongkun Li ◽  
Changbo He ◽  
Zhixin Zhang
Keyword(s):  
Wavelet Transform ◽  
Rolling Element Bearing ◽  
Noise Interference ◽  
Characteristic Extraction ◽  
Cyclic Frequency ◽  
Rolling Element ◽  
Transform Coefficients ◽  
Element Bearing ◽  
Weak Fault ◽  
Fault Characteristic

Rolling element bearing fault characteristic information is within the second-order cyclic stationary signal. However, it is susceptible to noise interference. In this article, a new method is proposed for rolling element bearing early fault characteristic extraction according to the cyclic periodogram method. The wavelet transform coefficients are processed and analyzed using the cyclostationary theory. As a result, the implicit cyclic characteristics are contained in wavelet transform coefficients. Therefore, using the modulus or envelope of wavelet transform coefficients instead of the calculation of the cyclic statistics can avoid the window function length selection while maintaining the computation rate. In addition, the calculation of correlated kurtosis is introduced into frequency domain to select optimal wavelet scales. The larger the correlated kurtosis, the stronger the cycle impact characteristic in wavelet coefficients. Calculating the cyclic frequency in the optimal wavelet scale range can accurately extract the weak fault characteristic information. The data processing results demonstrated that the proposed method outperforms existing cyclostationary signal analysis methods in weak fault feature extraction for rolling element bearing.

COMPOUND FAULT DIAGNOSIS OF BEARINGS USING AN IMPROVED SPECTRAL KURTOSIS BY MAXIMUM CORRELATION KURTOSIS DECONVOLUTION (MCKD).

2020 ◽  
Vol 9 (8) ◽  
pp. 66-72
Keyword(s):  
Fault Diagnosis ◽  
Resonance Frequency ◽  
Background Noise ◽  
Maximum Correlation ◽  
Vibration Signals ◽  
Filter Length ◽  
Frequency Bands ◽  
Noise Interference ◽  
Spectral Kurtosis

This paper discusses the use of Maximum Correlation kurtosis deconvolution (MCKD) method as a pre-processor in fast spectral kurtosis (FSK) method in order to find the compound fault characteristics of the bearing, by enhancing the vibration signals. FSK only extracts the resonance bands which have maximum kurtosis value, but sometimes it might possible that faults occur in the resonance bands which has low kurtosis value, also the faulty signals missed due to noise interference. In order to overcome these limitations FSK used with MCKD, MCKD extracts various faults present in different resonance frequency bands; also detect the weak impact component, as MCKD also dealt with strong background noise. By obtaining the MCKD parameters like, filter length & deconvolution period, we can extract the compound fault feature characteristics.

scholarly journals Weak Fault Detection of Tapered Rolling Bearing Based on Penalty Regularization Approach

Algorithms ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 184 ◽  
Author(s):  
Qing Li ◽  
Steven Liang
Keyword(s):  
Vibration Signal ◽  
Singular Values ◽  
Rolling Bearing ◽  
L1 Norm ◽  
Detection Approach ◽  
The Matrix ◽  
Noisy Observation ◽  
Weak Fault ◽  
Convex Regularization ◽  
Fault Information

Aimed at the issue of estimating the fault component from a noisy observation, a novel detection approach based on augmented Huber non-convex penalty regularization (AHNPR) is proposed. The core objectives of the proposed method are that (1) it estimates non-zero singular values (i.e., fault component) accurately and (2) it maintains the convexity of the proposed objective cost function (OCF) by restricting the parameters of the non-convex regularization. Specifically, the AHNPR model is expressed as the L1-norm minus a generalized Huber function, which avoids the underestimation weakness of the L1-norm regularization. Furthermore, the convexity of the proposed OCF is proved via the non-diagonal characteristic of the matrix BTB, meanwhile, the non-zero singular values of the OCF is solved by the forward–backward splitting (FBS) algorithm. Last, the proposed method is validated by the simulated signal and vibration signals of tapered bearing. The results demonstrate that the proposed approach can identify weak fault information from the raw vibration signal under severe background noise, that the non-convex penalty regularization can induce sparsity of the singular values more effectively than the typical convex penalty (e.g., L1-norm fused lasso optimization (LFLO) method), and that the issue of underestimating sparse coefficients can be improved.

scholarly journals An Improved Image Steganography Scheme Based on Partial Preservation Embedding Algorithm for Wireless Visual Sensor Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Qian Shen ◽  
Tao Jiang ◽  
Yongjun Zhu ◽  
Yin Wu
Keyword(s):  
Sensor Networks ◽  
Frequency Band ◽  
Poor Performance ◽  
Least Significant Bit ◽  
Medium Frequency ◽  
Visual Sensor ◽  
Secret Data ◽  
Visual Sensor Networks ◽  
Noise Interference ◽  
Wireless Visual Sensor Networks

With the continuous improvement of encryption algorithms, some applications based on the architecture of wireless visual sensor networks have gradually shifted their attention to the imperceptibility and antijamming performance of secret images. To reduce the probability of secret images being detected, the current research focuses on hiding secret data in the least-significant bit of the cover image in the spatial domain or embedding data into the coefficients of the high-frequency band in the transformational domain, which usually leads to poor performance in a hostile environment. Therefore, some researchers proposed to substitute the coefficients of the medium-frequency band in the transformational domain with secret information to enhance the anti-interference performance. However, this idea would severely affect the imperceptibility of secret images. As a result, an improved version based on the partial preservation embedding algorithm was designed in this paper. Theory analysis and simulation results indicate that the proposed scheme performs better than the existing methods by directly substituting the coefficients of the medium-frequency band in the transformational domain, especially in the case of strong noise interference.

scholarly journals Diagnostics 101: A Tutorial for Fault Diagnostics of Rolling Element Bearing Using Envelope Analysis in MATLAB

2020 ◽  
Vol 10 (20) ◽  
pp. 7302
Author(s):  
Seokgoo Kim ◽  
Dawn An ◽  
Joo-Ho Choi
Keyword(s):  
Process Simulation ◽  
Rolling Element Bearing ◽  
Fault Identification ◽  
New Developments ◽  
Envelope Analysis ◽  
Practical Applications ◽  
Spectral Kurtosis ◽  
Rolling Element ◽  
Element Bearing ◽  
Simulation Signal

This paper presents a MATLAB-based tutorial to conduct fault diagnosis of a rolling element bearing. While there have been so many new developments in this field, no studies have addressed the tutorial aspects in this field to help the engineers learn the concept and implement by their own effort. The three most common techniques—the autoregressive model, spectral kurtosis, and envelope analysis—are selected to demonstrate the bearing diagnosis process. Simulation signal is introduced to help understand the characteristics of fault signal and carry out the process toward the fault identification. The techniques are then applied to the two real datasets to demonstrate the practical applications, one made by the authors and the other by the Case Western Reserve University, which is known as a standard reference in testing the diagnostic algorithms.

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