High-frequency acoustic systems for robotic applications

Abstract

High-frequency ultrasonic systems, operating in the 200-kHz to 1-MHz frequency range and using air as the acoustic coupling medium are an effective complement to optical systems for robotic and industrial measurement applications. An air-coupled ultrasonic system was developed which produces well damped and focussed ultrasonic beams with good spatial resolution. Tests show that distance measurements with a resolution of 0.001 in. can be made through several inches of air at a rate of several hundred Hz. Focused transducers can reduce the effective area of measurement to below 0.05 in. at the focal point. The system was employed in several applications, including parts profiling, thickness testing, and the detection of missing parts. The apparent advantages that acoustic devices have over optical systems include lower cost by a factor of 5 or 10, and a higher speed of operation by perhaps 2 orders of magnitude.