PVF<inf>2</inf>Transducers for Acoustic Ranging and Imaging in Air

Abstract

PVF, transducers have becn fabricated and tested for use in acoustic imaqinq, pattern recoqnition and ranginq systems under development for robotic and intelligent machine tasks. is a metallized thin sheet of piezoelectric oolymer. The transverse excitation mode (d13) is employed to produce extension in the nlane of the film when a voltaqe is applied across the thickness of the film. Geometric boundary conditions enable the transverse dilatation of the film to be converted into a motion which results in the excitation of compressional waves in air. The deqree of curvature of the arch determines the directivity of the launched wave. The system apnlication requires t he sensor to possess at least 50' bandwidth via additional acoustic daminq. The active area of a tyDical element is 1 cm x 2 cm and can produce an audible continuous tone from 4 kHz to 16 kHz, with a Deak resDonse near 10 kHz. Device characteristics, ransinq, and a novel application of the a coustic v ersion of the radar sins-around t echnique to terrain tracking in robotic task control will be described. The transducer