Iranian Journal of Mechanical Engineering Transactions of ISME

Iranian Journal of Mechanical Engineering Transactions of ISME

An improved EMD method for noisy signal analysis in Time-Frequency domain

Authors
Abstract
Hilbert-Huang Transform is a new method for processing signals that applied to processing signals received from mechanical systems in recent years. This method for signals without noise leads to favorable results. However, in most cases the experimental signals are affected by the measurement noises which causes more complexity of signal processing and prevents extracting the correct information. In this paper, by applying some modifications to the Hilbert-Huang Transform, using the method for noisy signals has been provided. To this end, modifications have been done to the EMD method for signal decomposition. In the proposed method, instead of using Cubic Spline for the envelop curves, Smoothing Spline has been used. This modification causes to reduce noise effects and leads extracting better results from the experimental signal. Moreover, due to the complexity of experimental signals, sometimes stopping criterion used in common EMD method causes computational error and stops the program. By applying the modifications, the problem has been resolved as well.
To study the efficiency of the proposed method, vibration response of a cracked beam in presence of and without noise was analyzed in the Time-Frequency domain by both conventional and the modified methods. Results indicated the superiority of the modified method in the presence of noise.
Keywords

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Volume 16, Issue 1 - Serial Number 34
System Dyanamics and Solid Mechanics
Spring 2014
Pages 6-20

  • Receive Date 22 May 2014