Study on Fault Diagnosis Method of Planetary Gearbox Based on Turn Domain Resampling and Variable Multi-Scale Morphological Filtering

Abstract

The turn domain resampling (TDR) method is proposed in the paper on the basis of the existing angle domain resampling for solving the problem of non-fixed fault frequency under variable working conditions. TDR can select the appropriate sampling order according to the influence of frequency conversion, which avoided the error caused by the spline interpolation method. It can provide accurate parameters for the subsequent calculation of the equivalent frequency order. Variable multi-scale morphological filtering (VMSMF) method is proposed for the purpose of further reducing the interference of noise in resampling signal to feature extraction. VMSMF adaptively selects structural elements according to the parameter change of impact signal to make its scale more targeted. It only needs to calculate once using the optimal structural unit for a particular impact, and the filtering accuracy and operating efficiency have been greatly improved. The main steps of this article are as follows. First, the TDR is used to resample the original signal as to get the resampling signal which is still submerged by the strong noise. In the second step, VMSMF is used to filter the resampling signal to obtain the signal with less noise interference. Finally, the fault characteristics of the filtering signal was extracted and compared with the possible fault frequency calculated by the sampling parameters provided by resampling, so as to determine the fault type of the planetary gearbox. By analyzing the simulation signal and the experimental signal respectively, this method can find out the corresponding fault characteristics effectively.

Research on fault diagnosis of planetary gearbox based on variable multi-scale morphological filtering and improved symbol dynamic entropy

“…. The expansion operator eliminates the positive pulse, and the negative pulse is sharper, while the corrosion operator eliminates the negative pulse, and the positive pulse is sharper [11] .…”

“…(1) The experimental signal is variable speed signal, and the traditional fault feature extracted method will produce frequency ambiguity. In order to solve this problem, the paper first applied the Turn Domain Resampling (TDR) proposed by our group [11] to (2) The VMSMD proposed in this paper is used to de-noise the four groups of signals with different fault types after resampling, and then the envelope demodulation of the resampling signal is carried out. The processing results are shown in Fig.…”

“…The abovementioned multi-scale algorithms need repeated calculation of each scale, reducing the computational efficiency. In order to solve the above problems, Cui et al [11] proposed to use the Chebyshev window function as a structural element in 2021 and carried out noise reduction analysis on fault signals of planetary gearbox, achieving good results.…”

State of the art on vibration signal processing towards data‐driven gear fault diagnosis

“…They showed that the adaptive MMF is effective in extracting fault features. Liu et al proposed a variable multi-scale MMF method to filter resampling signals and obtain signals with less noise for feature extraction [55]. They used the Chebyshev window function as SE and opening-closing and closingopening mean as the morphological operator.…”

Research on fault diagnosis of planetary gearbox based on Variable Multi-Scale Morphological Filtering and improved Symbol Dynamic Entropy

“…(1) The experimental signal is variable speed signal, and the traditional fault feature extracted method will produce frequency ambiguity. In order to solve this problem, the paper first applied the Turn Domain Resampling (TDR) proposed by our group [11] to equivalently transform the signals with variable speed to the four health status signals collected. The original time domain signals and the resampled signals are shown in Fig.…”