Chaotic resonance in a fractional-order oscillator system with application to mechanical fault diagnosis

This paper is to generalize the research on chaotic resonance (CR) towards fractional-order chaotic systems and then develop a new technique for detecting weak signals embedded in strong background noise. For illustration, a fractional-order Duffing oscillator system is evaluated by means of bifurcation analysis, revealing the phenomenon of chaotic resonance, with the optimal driving amplitude falling within a chaotic interval. It is found that the weak signal can be amplified by the intrinsic fluctuations in the chaotic system instead of stochastic noise. Based on this investigation, a novel weak signal detection method is developed and successfully applied to mechanical fault diagnosis without the need of signal preprocessing. Extensive numerical results show that the signal-to-noise ratio of the incipient fault signal of machinery can be greatly improved.