<title>Control of broadband radiated sound with adaptive structures</title>

Abstract

Active structural acoustic control using adaptive structures has been demonstrated for harmonic disturbances. This paper presents an extension of this work to the attenuation of acoustic radiation from structures subject to broadband disturbances. An adaptive, multi-input multi-output (MIMO), feedforward broadband acoustic control system has been developed based on the least mean squares ELMS) algorithm, The compensators are adaptive finite impulse response FIR) filters. The control inputs are implemented with piezoelectric ceramic actuators. Both far-field microphones and polyvinylidene fluoride (PVDF) structural sensors designed to observe the efficient acoustic radiating modes are used as error sensors. The disturbance is band-limited zero mean white noise and is implemented with a point force shaker. In the control of hannonically excited systems, satisfactory attenuation is possible with a single-input single-output (5150) controller. In contrast, for systems excited with broadband disturbances, a MIMO controller is necessary for significant acoustic attenuation. Experimental results for the control of a simply supported plate are presented.

A broadband passive–active sound absorption system

“…Feedforward algorithms of this type have been successfully employed in various vibration and noise control scenarios including Active Structural Acoustic Control ͑ASAC͒ and Active Noise Control ͑ANC͒. 8,9 A block diagram for the SISO control system is given as Fig. 1.…”