Research On Vibration Signal Denoising Method Of Gearbox Of Offshore Engineering Platform Based On CEEMDAN-TFPF

Gear box is a very important component of mechanical equipment.The running state of gear box is related to the stability of the whole mechanical system.The health monitoring of the gearbox is usually achieved by analyzing the vibration signal of the gearbox.However,the vibration test signal contains a lot of noise,which will cover the effective information in the signal.Therefore,it is very important to reduce the noise of the test signal.Based on the traditional time-frequency peak filtering algorithm(TFPF),this paper proposes a CEEMDAN-TFPF joint denoising method combined with EMD decomposition.In this method,CEEMDAN is first used to decompose the signal,and TFPF is used to filter the decomposition results before reconstruction.This method can keep the adaptability of EMD method and the excellent noise reduction performance of TFPF method at the same time,and overcome the shortcomings of TFPF method to achieve a good balance between signal fidelity and noise suppression.The main content of this paper consists of the following three parts:Firstly,the kinds and characteristics of vibration excitation in gear fault mechanism are described,and several common fault forms of gear box are discussed based on vibration mechanism.The finite element method was used to simulate the dynamics of the gearbox.Through the simulation of the normal gearbox and the fault gearbox,the vibration signals under different working conditions were obtained,and the vibration signals were analyzed to study and compare the vibration characteristics of the gearbox under different operating conditions.Secondly,the CEEMDAN decomposition method and time-frequency peak filtering denoising algorithm are studied theoretically.The basic principles,advantages and disadvantages of the CEEMDAN decomposition method and the improved CEEMDAN decomposition method are described.Based on the shortcomings of traditional TFPF denoising algorithm and CEEMDAN denoising method,a CEEMDAN-TFPF combined denoising method was proposed.Then,the digital simulation signal generated by the program is used to verify the noise reduction method proposed in this paper.The simulation results of high SNR and low SNR signals respectively show that the joint denoising method is feasible,and its performance is better than that of single method,and it can effectively retain the useful components in the signal while suppressing the noise.Finally,a test bed was set up to test the vibration of the gearbox,and the vibration signals were filtered by the joint denoising method.The reliability of the denoising method was verified by the actual signals,and the results were used as the basis for subsequent fault diagnosis.The frequency characteristics of the vibration were obtained by Fourier frequency domain analysis method.The reliability of the joint noise reduction method is verified by testing the gearbox in normal state and fault state and analyzing the noise reduction results with the traditional method.The results show that the combined method has better noise reduction performance than the single method.