Adaptive stochastic resonance in bistable system driven by noisy NLFM signal: phenomenon and application

Author(s):  
Chen Yang ◽  
Jianhua Yang ◽  
Dengji Zhou ◽  
Shuai Zhang ◽  
Grzegorz Litak

The stochastic resonance (SR) in a bistable system driven by nonlinear frequency modulation (NLFM) signal and strong noise is studied. Combined with empirical mode decomposition (EMD) and piecewise idea, an adaptive piecewise re-scaled SR method based on the optimal intrinsic mode function (IMF), is proposed to enhance the weak NLFM signal. At first, considering the advantages of EMD for dealing with non-stationary signals, the segmented NLFM signal is processed by EMD. Meanwhile, the cross-correlation coefficient is used as the measure to select the optimal IMF that contains the NLFM signal feature. Then, the spectral amplification gain indicator is proposed to realize the adaptive SR of the optimal IMF of each sub-segment signal and reconstruct the enhanced NLFM signal. Finally, the effectiveness of the proposed method is highlighted with the analysis of the short-time Fourier transform spectrum of the simulation results. As an application example, the proposed method is verified adaptability in bearing fault diagnosis under the speed-varying condition that represents a typical and complicated NLFM signal in mechanical engineering. The research provides a new way for the enhancement of weak non-stationary signals. This article is part of the theme issue ‘Vibrational and stochastic resonance in driven nonlinear systems (part 1)’.

2013 ◽  
Vol 706-708 ◽  
pp. 1331-1334
Author(s):  
Kai Tuo Zhang ◽  
Ming Li

It can obtain intrinsic mode function (IMF) of signal wave with empirical mode decomposition (EMD) in harmonic analysis of power system. Harmonic frequency, amplitude and duration can be obtained through analysis of IMFs. Through EMD analysis on distortion waveform of single-phase AC inverter output as an example, combined with applied scene of distorted voltage, cause of distortion waveform can be deduced. The result shows that EMD analysis on non-stationary signals is of good performance, and a new substitute method of FFT transform in harmonic analysis.


2011 ◽  
Vol 141 ◽  
pp. 21-25
Author(s):  
Ying Zhang ◽  
Shu Ming Li

Noise, bistable system and input signal are the three essential factors in stochastic resonance (SR). The noise-induced SR method, the parameter-tuning SR method, and the twice sampling SR method change the characteristics of the noise, the bistable system and the input signal, respectively. With the new cooperation, they can all produce the SR phenomena when the system exceeds the small-parameter area. If treating the strong noise and the input signal with large frequency, the actions of the system parameters can build the system behavior in an orderly way, associated with the twice sampling frequency. The united parameter-tuning SR method adjusts the system parameters to fit the normalized frequency after the twice sampling SR, in order to make the optimal noise intensity. The application to the flow meter vibration test has presented the practicability and effectiveness of the united parameter-tuning SR method.


2021 ◽  
pp. 2150047
Author(s):  
Shuai Zhang ◽  
Jianhua Yang ◽  
Canjun Wang ◽  
Houguang Liu ◽  
Chen Yang

Stochastic resonance (SR) and self-induced stochastic resonance (SISR) are two kinds of important dynamical phenomena in the nonlinear system. SR occurs at the frequency of the characteristic signal. However, SISR can occur at a frequency that is included in the excitation. In present, there are volumes of literatures focusing on extracting the bearing fault characteristics from the vibration signal by SR method. However, the occurrence of SISR may result in the fault features misjudgment in SR processing. Through experimental verifications, we find that the interference of SISR is illustrated strongly in the fault characteristics identification. More importantly, the transition from SISR to SR corresponds to the evolution process of bearing state from normal to damage. Therefore, this evolutionary process can not only judge the state of bearing, but also describe the severity of bearing failure. The result is verified by processing the signals of bearing fault with different severity in noise background. They are the most important findings in this work.


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