Noise reduction method of fan gearbox vibration signalbased on variational mode decomposition

XU Zhi-hua1, PAN Ting-long2
(1.Electrical Engineering College, Yancheng Institute of Technology, Yancheng 224051, China;
2.IoT Engineering College, Jiangnan University, Wuxi 214000, China)

Abstract: Aiming at the problem that the vibration signal noise of the fan gear box interfered with the system fault diagnosis，the method of signal noise reduction was studied. A method based on variational modal analysis was proposed to preprocess the data, and the collected signal was removed by Wiener filtering. Variational mode decomposition iteration was used to find the optimal solution of the model, the frequency center and bandwidth of each component was determined, and the effective separation of different frequency components was realized. A completely non-recursive decomposition model was used to avoid modal aliasing in empirical mode decomposition effectively. The characteristics of local mean decomposition were used to perform spectral analysis on the decomposition results，which was used as the basis for the selection of the number of modes K, so that the K value was optimal. The method was verified by simulation. The results show that the prop method achieves good noise reduction effect while avoiding modal aliasing and has strong robustness, which can greatly reduce the interference of vibration signal noise.
Key words: variational mode decomposition(VMD); empirical mode decomposition(EMD); local mean decomposition（LMD）; gearbox vibration; noise reduction