Bearing fault diagnosis through stochastic resonance by full-wave signal construction with half-cycle delay

Stochastic resonance (SR) can enhance the weak fault-induced impulses in envelope signal. However, envelope signal is a unipolar half-wave signal which is worse than bipolar full-wave signal for SR effect. To convert envelope signal into bipolar full-wave signal, two full-wave signal construction (FSC) methods based on mirror-cycle-add (MCA) operation are proposed called FSCBME and FSCBHCD. FSCBME is to find the lag time, an important MCA parameter, that maximizes the energy of the constructed full-wave signal. FSCBHCD is to make the lag time equal to half of the driving signal cycle. Regarding the constructed full-wave signal as SR input, two novel SR methods are proposed called FSCBMESR and FSCBHCDSR. Simulations and cast study are done. Simulations prove that the robustness and anti-noise capability of FSCBHCD is better than FSCBME, and FSCBHCDSR performance is better than FSCBMESR performance. Case study proves that FSCBHCDSR is more effective than FSCBMESR in bearing fault diagnosis. (C) 2019 Elsevier Ltd. All rights reserved.