Time-Frequency Analysis of Cabin Noise Using EEMD-ICA Approaches

Abstract

The interior noise of construction machinery is complex non-stationary signal caused by a variety of excitation source; the noise source must be determined to minimize its radiation. There are, however, considerably fewer techniques available if only a single-channel measurement is available and yet single-channel measurements are important where minimal instrumentation complexity is required. The combined techniques of empirical mode decomposition (EEMD) and the improvement of independent component analysis (ICA) were applied to analysis the parotic noise signals of bulldozer cabin in our study. According to the correlated measurement standard, the combining method of experiment and analysis for the cabin interior and outside noise and vibration signals was applied to research the noise source effectively. With the experiment and coherence analysis for the cabin interior and outside noise and vibration signals, the techniques of EEMD-ICA were valid on the noise source separation and identification. Taking into account the machine running characteristics and the layout of machine structures, and based on the frequency characteristics of the noise and vibration signals, we concluded that the main sources of indoor noise was combustion noise of diesel engine and mechanical radiation noise of cabin parts caused by the diesel engine vibration transmission. Generation of noise sources, transmission paths of air-borne or structure-borne noises were well researched in order to control the interior noise. Finally, some modifications were taken for different noise sources and the noise level was reduced to a satisfied level.