Acoustic-based wireless signal transmission for precision metrology: Accuracy and reliability

Metallic shielding of electromagnetic waves presents a roadblock for machine tool and process monitoring. Acoustic waves, alternatively, provide a viable mechanism, due to their inherent transmissibility in metals. This paper presents a quantitative analysis of factors affecting the performance of acoustic-based signal transmission including carrier frequency, bandwidth, signal-to-noise ratio, data bit-rate, etc. Signal attenuation and data loss due to wave diffraction and reflection is first numerically studied using finite element models of representative machine structures. Experimental evaluation of these models with operating production machinery quantifies the accuracy and reliability of in situ acoustic signal transmission methods for precision metrology in manufacturing.