Periodical sparse-assisted decoupling method for local fault detection of spiral bevel gears

Early fault detection for spiral bevel gears is crucial to ensure normal operation and prevent accidents. The harmonic components, excited by the time-varying mesh stiffness, always appear in measured vibration signal. How to extract the periodical impulses that indicate gear localized fault buried in the intensive noise and interfered by harmonics is a challenging task. In this paper, a novel Periodical Sparse-Assisted Decoupling (PSAD) method is proposed as an optimization problem to extract fault feature from noisy vibration signal. The PSAD method decouples the impulsive fault feature and harmonic components based on the sparse representation method. The sparsity within and across groups property and the periodicity of the fault feature are incorporated into the regularizer as the prior information. The nonconvex penalty is employed to highlight the sparsity of fault features. Meanwhile, the weight factor based on ℓ₂ norm of each group is constructed to strengthen the amplitude of fault feature. An iterative algorithm with Majorization–Minimization (MM) is derived to solve the optimization problem. Simulation study and experimental analysis confirm the performance of the proposed PSAD method in extracting and enhancing defect impulses from noisy signal. The suggested method surpasses other comparative methods in extracting and enhancing fault features.