Five axis programmable positioning system for underwater acoustic measurements at Penn State

Abstract

To facilitate underwater acoustic measurements at Penn State, a five axis computer controlled positioning system has been developed by the author and installed in the new water tank facilities at the Applied Research Laboratory. Providing linear motion in three directions and rotations about two axes, the system allows an acoustic transducer to be positioned and oriented at virtually any position and direction within the water tank. Motion is controlled along each axis via programmable controllers (indexers) which are in turned accessed by a computer via RS 232. Resolution in the linear directions is 0.005 in. Angular resolution is 0.18°. Working in conjunction with the appropriate data-acquisition hardware and software, the positioning system allows the entire measurement procedure to be automated. Although designed initially for use in monostatic and bistatic surface scattering experiments, the system is also being used for other interesting underwater experiments, including bottom sediment studies, and the effects of thermal gradients on acoustic signals.