Piezoelectric Array Sensing for Real-Time, Broad-Band Sound Radiation Measurement

Abstract

This paper proposes a noise radiation sensor consisting of an array of independent piezoelectric patches connected to an adaptive linear combiner. The coefficients of the linear combiner are adapted in such a way that the mean-square error between the reconstructed volume displacement (or velocity) and either numerical or experimental data is minimized. A numerical study is conducted, to analyze the influence of the size of the piezoelectric array on the reconstructed volume velocity. a X Fig. 1 QWSIS sensor [4] 446 Transactions of tlie ASIUIE Downloaded From: http://vibrationacoustics.asmedigitalcollection.asme.org/ on 06/08/2015 Terms of Use: http://asme.org/terms

Piezoelectric Sensor Configuration for Active Structural Acoustic Control

“…Based on similar reasoning it is also clear that inhomogeneous plates can be used together with the method provided the displacement at the boundary is zero. However, in the case of boundary conditions deviating strongly from the simply supported case, it may be better to estimate the exact eigenfunctions [3]. In combination with the method of the present paper, this leads to a method for sound radiation estimation without delay with an array of piezoelectric patch sensors that is valid for all zero-displacement boundary conditions.…”

“…The plate displacements w N are obtained by evaluating equation (3) at x"x N and y"y N , where s3+0, 2 , N, respectively. Like points p, sensors j can be centered on half-mesh points, as used in reference [3]. In that case, however, the weighting coe$cients can not be obtained with the discrete sine transform as used above and should be obtained by other means, such as with a least-squares technique.…”

“…At low frequencies the dominant radiation mode is the volume velocity. A paper by Preumont et al [3] gives a method to determine the volume velocity from measurement with an array of piezoelectric strain sensors. In the latter paper, a method is also given to calibrate the sensor con"guration by using an adaptive linear combiner.…”

Piezoelectric Array Sensing of Volume Displacement: A Hardware Demonstration

“…The "nal equation (4) relating the volume displacement to the electric charges has the form of a linear combiner with constant coe$cients G . In reference [8], the coe$cients G were determined analytically for a beam, starting from the orthogonality relations. It was also shown numerically that they can be reconstructed from an adaptive linear combiner (see Figure 2) which minimizes the mean-square error between the estimated volume displacement < K , the output of the linear combiner, and the actual volume displacement <.…”

“…Alternative strategies for evaluating the total radiated acoustic power from a set of discrete strain information at a regular mesh were developed in reference [7], but these approaches were computationally intensive and were not suited to real-time applications with the existing microprocessor technology. A previous study [8] attempted to eliminate the drawbacks associated with the aforementioned methods by reconstructing the volume displacement through a set of discrete strain sensors connected to an adaptive linear combiner (see Figure 1). This paper describes an experimental demonstration of the volume displacement sensor and reexamines the way that the coe$cients of the linear combiner can be obtained experimentally.…”