Sensor scheme design for active structural acoustic control

Abstract

Efficient sensing schemes for the active reduction of sound radiation from plates are presented based on error signals derived from spatially weighted plate velocity or near-field pressure. The schemes result in near-optimal reductions as compared to weighting procedures derived from eigenvector or singular vector analysis of the radiation operator. Efficient control configurations are suggested using a, possibly analog, front-end implementing a bank of spatial weighting functions and a digital controller with a minimized number of input and output channels. The performance of different weighting functions is compared, as well as the performance of different frequency-dependent filtering functions. Design rules are given for the sensor spacing, the number of weighting functions, the number of actuators, and the corresponding controller dimensionality.

On the Sound Radiation From a Circular Hatchway

“…An approximate low-frequency formula for calculating the elements of R when fluid loading is neglected is given by Berkhoff [8]:…”

An Efficient Finite Element Approach for Reduction of Struc-Tural Vibration and Acoustic Radiation by Passive Shunted Pie-Zoelectric Systems

“…This is done by using the elemental radiators decomposition described in previous works [3,6,9,16]. This method, which assumes that the sound radiation is due to a number of discrete pistons in harmonic oscillation, can be applied to any plane surface in an infinite baffle.…”

“…The use of piezoelectric materials for vibration damping and noise suppression of flexible structures, both in active control [3,6,9,21] and in passive control [4, 7-8, 12-13, 15-24], is widely discussed in the literature. These materials, which can be used as sensors or actuators, or even both simultaneously, enable the transformation of mechanical energy into electric energy (direct piezoelectric effect) and vice-versa (indirect piezoelectric effect).…”

Simulation study of active control of vibro-acoustic response by sound pressure feedback using modal pole assignment strategy

“…Besides the acoustic sensing and acoustic objective functions, structural sensing approaches 11,12 and structural objective functions [13][14][15] such as squared velocity, volume velocity, and weighted sum of spatial gradients were studied for ASAC. Berkhoff 16 discussed sensor scheme design for the active reduction of sound radiation from plates based on error signals derived from spatially weighted plate velocity or near-field pressure. In this paper, microphones are not used as error sensors; the acoustic pressures from the microphones are not sought to be minimized but to feedback for pole assignment for the active control of vibro-acoustic response.…”