4/19/2023 0 Comments Vmd measure distance![]() Common signal decomposition methods include wavelet transform (WT), empirical mode decomposition (EMD), and variational mode decomposition (VMD). There are many general signal denoising methods, whose basic idea is to extract and reconstruct useful signal components through some criteria. Therefore, it is of great significance to effectively remove the noise in time domain load signals for the durability analysis of agricultural machinery. Usually, measured signals are nonstationary and contain a lot of noise due to the complex and changeable working environment, which makes it meaningless to apply measured signals directly to durability analysis. The basis of durability design of agricultural vehicles is to obtain time domain load signals, which can reflect the real working condition. Thus, it is of great significance to analyze the fatigue durability of the mechanical structure. ![]() ![]() Introductionįatigue failure is one of the main causes of mechanical failure. Effectiveness of the proposed method is verified through experiments of the measured load signals. Experimental results of synthetic signals demonstrate that the presented method outperforms the conventional digital signal denoising methods and the related methods proposed recently. Finally, SSA is implemented for the reconstructed signal. Then, the signal-dominant BLIMFs are reconstructed with the noise-dominant BLIMFs processed by WTD. In addition, weighted-permutation entropy (WPE) is applied to divide the BLIMFs into signal-dominant BLIMFs and noise-dominant BLIMFs. Meanwhile, the noisy signal is adaptively decomposed into band-limited intrinsic mode functions (BLIMFs) by using VMD. Detrended fluctuation analysis (DFA) is adopted to obtain the noise level of the noisy signal, which can optimize the selection of MIE threshold. Firstly, a simple criterion based on mutual information entropy (MIE) is designed to select the proper mode number for VMD. In this paper, a signal denoising method based on variational mode decomposition (VMD), wavelet threshold denoising (WTD), and singular spectrum analysis (SSA) is proposed. However, in the process of signal acquisition, time domain load signals are easily contaminated by noise. Measured load data play a crucial role in the fatigue durability analysis of mechanical structures.
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