ASA 124th Meeting New Orleans 1992 October

4aSA1. Active structural acoustic control of radiation due to broadband disturbances.

Jerome P. Smith

Chris R. Fuller

Ricardo Burdisso

Vib. and Acoust. Labs., Dept. of Mech. Eng., Virginia Polytech. Inst. and State Univ., Blacksburg, VA 24061

Active structural acoustic control (ASAC) using the adaptive feedforward LMS algorithm has been demonstrated for narrow-band (harmonic) disturbances. This paper presents an extension of this work to the attenuation of acoustic radiation from structures subject to broadband (random) disturbances. The control compensators are adaptive finite impulse response (FIR) filters. The LMS control algorithm is implemented on a floating point digital signal processor. The control inputs are implemented with piezoelectric ceramic actuators (PZT), and both polyvinylidene flouride (PVDF) structural sensors designed to observe the efficient acoustic radiating modes and far-field microphones are used as error sensors. In the control of harmonically excited systems, satisfactory attenuation is achieved with a single-input, single-output (SISO) controller. In contrast, for systems excited with broadband disturbances, a multi-input, multi-output (MIMO) controller is necessary for significant acoustic attenuation. A MIMO broadband acoustic control system is developed and results for the control of a simply supported plate is presented. [Work supported by Office of Naval Research.]