Lihui Fu

Shijiazhuang Railway Institute, Chentow, Hebei, China

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Publications (12)1.09 Total impact

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    Hui Li, Lihui Fu, Haiqi Zheng
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    ABSTRACT: The rolling element bearing characteristic frequencies contain very little energy and are usually overwhelmed by noise and higher level of structural vibrations. The continuous wavelet transform enables one to look at the evolution in the time scale joint representation plane. This makes it very suitable for the detection of singularity generated by localized defects in a mechanical system. However, most applications of the continuous wavelet transform have widely focused on the use of the Morlet wavelet transform. The complex Hermitian wavelet is constructed based on the first and the second derivatives of the Gaussian function to detect signal singularities. The Fourier spectrum of Hermitian wavelet is real, which the Fourier spectrum has no complex phase and the Hermitian wavelet does not affect the phase of a signal in complex domain. This gives the desirable ability to detect the singularity characteristic of a signal precisely. In this study, the Hermitian wavelet amplitude and phase map are used in conjunction to detect and diagnose the bearing fault. The Hermitian wavelet amplitude and phase map are found to show distinctive signatures in the presence of bearing inner race or outer race damage. The simulative and experimental results show that the Hermitian wavelet amplitude and phase map can extract the transients from strong noise signals and can effectively diagnose bearing faults. KeywordsFault diagnosis–Hermitian wavelet transform–Bearing–Amplitude and phase map–Signal processing
    Journal of Mechanical Science and Technology 01/2011; 25(11):2731-2740. · 1.09 Impact Factor
  • Hui Li, Lihui Fu, Zhentao Li
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    ABSTRACT: A new approach to fault diagnosis of gear wear based on Teager-Huang transform is presented. This method is based on Empirical Mode Decomposition (EMD) and Teager Kaiser Energy Operator (TKEO) technique. EMD can adaptively decompose the vibration signal into a series of zero mean Amplitude Modulation-Frequency Modulation (AM-FM)Intrinsic Mode Functions (IMFs). TKEO can track the instantaneous amplitude and instantaneous frequency of the AM-FM component at any instant. The experimental examples are conducted to evaluate the effectiveness of the proposed approach. The experimental results provide strong evidence that the performance of the Teager-Huang transform approach is better to that of the Hilbert-Huang transform approach for gear fault detection. Teager-Huang transform can effectively diagnose the faults of the gear wear.
    Artificial Intelligence, 2009. JCAI '09. International Joint Conference on; 05/2009
  • Hui Li, Lihui Fu, Yuping Zhang
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    ABSTRACT: A new demodulation approach to fault diagnosis of bearing based on Teager energy operator (TEO) technique is presented. Firstly, TEO can tracks the modulation energy of the vibration signal and estimates the instantaneous amplitude. Secondly, the envelope spectrum is applied to the instantaneous amplitude. Therefore, the character of the bearing faults can be recognized according to the envelope spectrum. The experimental results show that envelope spectrum based on Teager energy operator technique can effectively diagnose the faults of the bearing.
    Measuring Technology and Mechatronics Automation, 2009. ICMTMA '09. International Conference on; 05/2009
  • Hui Li, Lihui Fu, Zhenjiang Shi
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    ABSTRACT: The speed-up and speed-down of the gearbox are non-stationary process and the vibration signal can not be processed by traditional processing method. In order to process the non-stationary vibration signals such as speed-up or speed-down signals effectively, the order envelope analysis technique is presented. This new method combines order tracking technique with envelope spectrum analysis. Firstly, the vibration signal is sampled at constant time increments and then uses software to resample the data at constant angle increments. Therefore, the time domain non-stationary signal is changed into angle domain stationary signal. In the end, the resampled signals are processed by envelope spectrum analysis. The experimental results show that order envelope spectrum analysis can effectively diagnosis the faults of the gear crack.
    Measuring Technology and Mechatronics Automation, 2009. ICMTMA '09. International Conference on; 05/2009
  • Lihui Fu, Hui Li, Yaning Wang
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    ABSTRACT: The bi-cepstrum technique is presented based on bi-spectrum and cepstrum analysis. This new method combines bi-spectrum technique with cepstrum analysis. Firstly, in order to eliminate the noise effects, the bi-spectrum is calculated. Then the bi-spectrum is processed by bi-cepstrum technique. The experimental results show that bi-cepstrum technique can effectively diagnosis the faults of the gear.
    Measuring Technology and Mechatronics Automation, 2009. ICMTMA '09. International Conference on; 05/2009
  • Hui Li, Lihui Fu, Haiqi Zheng
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    ABSTRACT: Rolling element bearings vibrations are random cyclostationary signals which are a combination of periodic and random processes due to the machine's rotation cycle and interaction with the real world. The combinations of such components are best considered as cyclostationary. This paper discusses which second order cyclostationary statistics should be used for fault diagnosis of bearing. The second order cyclostationary statistical methods are firstly introduced and then applied to fault detection of bearing. This approach is capable of completely extracting the characteristic fault frequencies related to the defect. Experiment results show that the second order cyclostationary statistics is powerful and effective in feature extracting and fault detecting for rolling element bearings.
    Image and Signal Processing, 2009. CISP '09. 2nd International Congress on; 01/2009
  • Shufeng Ai, Hui Li, Lihui Fu
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    ABSTRACT: In order to process the non-stationary vibration signals during run-up of gearbox, the method based on angle domain average and autoregressive spectrum analysis is presented. This new method combines angle domain average with angle domain average technique. Firstly, the vibration signal is sampled at constant time increments and then uses software to resample the data at constant angle increments.Secondly, the angle domain signal is preprocessed using angle domain average technique in order to eliminate the unrelated noise. In the end, the averaged signals are processed by autoregressive spectrum analysis. The experimental results show that the proposed method can effectively detect the gear crack faults.
    First IITA International Joint Conference on Artificial Intelligence, Hainan Island, China, 25-26 April 2009; 01/2009
  • Shufeng Ai, Hui Li, Lihui Fu
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    ABSTRACT: The order bi-cepstrum technique is introduced and applied effectively to gearbox faults diagnosis under run-up condition. This new method combines order tracking technique with bi-cepstrum analysis. The resampling signal can be obtained by resampling of the vibration signal that has been sampled in the time domain. Therefore, the time domain transient signal is changed into angle domain stationary signal. In the end, the resampled signals are processed by bi-cepstrum technique. The experimental results show that order bi-cepstrum technique can effectively diagnosis the faults of the gear crack.
    FSKD 2009, Sixth International Conference on Fuzzy Systems and Knowledge Discovery, Tianjin, China, 14-16 August 2009, 6 Volumes; 01/2009
  • Hui Li, Lihui Fu, Zhengtao Li
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    ABSTRACT: Varying speed machinery fault diagnosis is more difficult due to non-stationary machine dynamics and vibration. A new approach to fault diagnosis of bearing under running up based on angle domain average and Hilbert-Huang transform (HHT) phase map is presented. The non-stationary vibration signals are transformed from the time domain transient signal to angle domain stationary one using order tracking. Empirical mode decomposition (EMD) can adaptively decompose the vibration signal into a series of zero mean Intrinsic Mode Functions (IMFs). Hilbert transform can track the instantaneous amplitude and instantaneous frequency of the intrinsic mode functions at any instant. The experimental results show that average domain average and Hilbert-Huang transform phase map can effectively diagnosis the faults of the gear crack.
    01/2009;
  • Hui Li, Lihui Fu, Haiqi Zheng
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    ABSTRACT: Envelope spectrum analysis is widely used to detection bearing localized fault. In order to overcome the shortcomings in the traditional envelope analysis in which manually specifying a resonant frequency band is required, a new approach based on the fusion of the Laplace wavelet transform and envelope spectrum is proposed for detection and diagnosis defects in rolling element bearings. This approach is capable of completely extracting the characteristic fault frequencies related to the defect. Experiment results show that the proposed approach is sensitive and reliable in detecting defects on the inner race and outer race of bearings.
    01/2009;
  • Shufeng Ai, Hui Li, Lihui Fu
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    ABSTRACT: A novel method to fault diagnosis of gear crack based on empirical mode decomposition (EMD) and autoregressive (AR) spectrum is presented. This method can carry out empirical mode decomposition and extract feature information of different machine parts in condition monitoring and fault diagnosis of machinery. The main objective of empirical mode decomposition is to separate the time series data into components with different time scale. Then the AR model estimation is applied to each intrinsic mode function and the AR spectrum is obtained. As an example, the vibration signal of a gearbox is analyzed. The experimental results show that this method based on empirical mode decomposition and autoregressive spectrum can effectively diagnose the crack faults of gear.
    Measuring Technology and Mechatronics Automation, International Conference on. 01/2009; 1:673-676.
  • Lihui Fu, Hui Li
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    ABSTRACT: The degree of cyclostationarity technique is introduced and applied effectively to gearbox faults diagnosis under run-up condition. This new method combines order tracking technique with second order cyclo-stationary statistics analysis. The resampling signal can be obtained by resampling of the vibration signal that has been sampled in the time domain. Therefore, the time domain transient signal is transformed into angle domain stationary signal. In the end, the resampled signals are processed by degree of cyclostationarity technique. The experimental results show that degree of cyclostationarity technique can effectively diagnosis the faults of the gear crack.
    01/2009;