A weak signal feature extraction method is proposed based on double coupled Duffing oscillator stochastic resonance (SR). In this method, the doubly coupled stochastic resonance system consists of two Duffing oscillators. Stochastic resonance is generated in the coupled stochastic resonance system by the synergy of input weak signal and noise, so that signal to noise ratio (SNR) of output signal is enhanced. The influences of different parameters on SR are researched by SNR. The scale transformation method is used to realize the detection of large frequency signals. At first, the large frequency is compressed into a small frequency to satisfy the stochastic resonance through the twice sampling frequency. Finally, the feature extraction of weak fault signal is realized through the scale recovery. The analysis results of simulation signal and example signal of rolling element bearing show that this method can effectively extract the fault feature information of weak signal. The experimental results show that this method is more effective for weak signal detection than the Duffing oscillator detection.
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