THE ENHANCEMENT OF IMPULSIVE NOISE AND VIBRATION SIGNALS FOR FAULT DETECTION IN ROTATING AND RECIPROCATING MACHINERY

Abstract

Impulsive sound and vibration signals in machinery are often caused by the impacting of components and are commonly associated with faults. It has long been recognized that these signals can be gainfully used for fault detection. However, it tends to be difficult to make objective measurements of impulsive signals because of the high levels of background noise. This paper presents an enhancement scheme to aid the measurement and characterization of such impulsive sounds, called a two-stage Adaptive Line Enhancer (ALE), which exploits two adaptive filter structures in series. The resulting enhancer signals are analyzed in the time–frequency domain to obtain simultaneous spectral and temporal information. In order to apply the two-stage ALE successfully, the filter parameters and adaptive algorithms should be chosen carefully. Conditions for the choice of these parameters are presented and suggestions are made for suitable adaptive algorithms. Finally, the techniques developed are applied to the diagnosis of faults within an internal combustion engine and to data from an industrial gearbox.