Gear case coupling modulation signal separation method based on inner product transformation and correlation filtering

Abstract

The invention discloses a gear case coupling modulation signal separation method based on inner product transformation and correlation filtering. According to the method, on the basis of the structure parameter (like the number Z of teeth) and the operational state (like the rotating frequency fn), a parsing dictionary Ds(t) capable of representing a stable modulation signal is constructed; an inherent frequency fd and a damping ratio Xi that correspond to the impact are identified in a gear case vibration acceleration signal x(t) by using a correlation filter method and an adaptive dictionary Dc(t) capable representing an impact modulation signal is constructed; and according to inner product transformation and correlation analyzing of the x(t), the Ds(t), and the Dc(t), sparse decomposition is carried out on the x(t) so as to obtain a primary function DS(t) and a coefficient Ai that are capable of expressing a stable modulation signal as well as a primary function DC (t) and a coefficient Bi that are capable of expressing an impact modulation signal, and separation is carried out to obtain a stable modulation signal Dpw(t) that is equal to sigma Ai DS (t) and an impact modulation signal Dcj(t) equal to sigma Bi DC (t). The method for constructing a parsing dictionary has advantages of both the parsing method and the adaptive method; and the physical significance is explicit. No complete orthogonality is required and the universality is high. The coupling modulation separation result is precise and reliable; and the anti-noise performance is good. A defect that the weak impact can not be extracted easily according to the traditional method can be overcome.

Description

technical field [0001] The invention relates to the fields of power machinery and signal processing, in particular to a gearbox coupling modulation signal separation method based on inner product transformation and correlation filtering. Background technique [0002] When the gearbox has tooth distribution defects or damage faults, the amplitude of the vibration signal will change during the gear meshing process, resulting in a smooth modulation of the amplitude. The modulated vibration response model can be represented by formula (2-1). Where: x m is the amplitude of the mth order meshing frequency component, is the phase of the mth order meshing frequency component, f z is the gear meshing frequency; A m,k is the amplitude of the kth order component of the mth order amplitude modulation function, α m,k its phase, f n is the rotational frequency of the defective gear shaft. [0003] [0004] The spectrum obtained by Fourier transforming x(t) is the meshing freque...

AI Technical Summary

Problems solved by technology

When there are distributed and concentrated faults in the gearbox at the same time, because the modulation sideband characteristics of the two faults on the spectrum are consistent, the smooth modulation and the shock modulation are coupled with each other, and the traditional spectrum analysis and demodulation analysis are difficult to diagnose the fault.

Especially when the meshing frequency and natural frequency of the gearbox overlap, even the wavelet transform, which has many advantages, is difficult to effectively separate the smooth modulation and the shock modulation for fault diagnosis; wavelet analysis also requires the basis function to be orthogonal, in terms of signal separation has greater limitations

The sparse decomposition method has advantages in separating multi-component signals, but the sparse dictionary can only be constructed through the analytical method or the adaptive method, the physical meaning of dictionary atoms is not clear, the versatility is not good, and the anti-noise performance is poor

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