Paper Title
Fault Detection of Helicopter Gearbox Using Empirical Wavelet Decomposition and Shock Filter

Abstract
This study proposes a signal processing procedure for early detection of gears defects .This procedure is based on Empirical Wavelet Decomposition (EWD) and a shock filter. EWD employ an adaptive process that is able to decompose the vibration signal into a finite number of Intrinsic Mode Functions (IMFs) according to the information located in the spectrum of the original signal. In this paper a shock filter is proposed to inspect and quantify the shock contents of the obtained IMFs. The presence of periodic shocks is generally considered as abnormal phenomena in most rotating machinery and as reflecting the effect of defects. The Shock filter makes it possible to extract and isolate the impulsive part of the signal and eliminates the energy contribution of noise and random components. The results of the proposed procedure confirmed its ability in detecting the fault characteristic frequency, which validates its feasibility in the diagnosis of gear defects. Keywords - EWD, Shock Filter, Fault Detection, Gears, Signal Processing.