Acoustic holography — A robot application

摘要

Acoustic holography is a technique to visualize the sound field propagating from a sound source. It is used to analyse and locate sources of noise, and even allows to predict the propagation of sound in the environment. However, this technique involves simultaneous measurements of up to 256 microphones, arranged in an array. We propose an alternative approach with 4 or less microphones which are re-positioned using an articulated robot arm. Provided the measurement conditions are stable, this alternative approach with consecutive measurements allows to make use of acoustic holography to investigate various sources of noise. The case of fan noise is demonstrated where the focus is put on practical aspects conducting near-field acoustic holography experiments using a robot arm, as well as post-processing measurement data. As a result, 2 complimenting techniques, static and dynamic near-field acoustic holography, are introduced and their merits are discussed.