Virtual sensors for active noise control in acoustic-structural coupled enclosures using structural sensing: Part II—Optimization of structural sensor placement

Abstract

The work proposed an optimization approach for structural sensor placement to improve the performance of vibro-acoustic virtual sensor for active noise control applications. The vibroacoustic virtual sensor was designed to estimate the interior sound pressure of an acousticstructural coupled enclosure using structural sensors. A spectral-spatial performance metric was proposed, which was used to quantify the averaged structural sensor output energy of a vibroacoustic system excited by a spatially varying point source. It was shown that (i) the overall virtual sensing error energy was contributed additively by the modal virtual sensing error and the measurement noise energy; (ii) each of the modal virtual sensing error system was contributed by both the modal observability levels for the structural sensing and the target acoustic virtual sensing; and further (iii) the strength of each modal observability level was influenced by the modal coupling and resonance frequencies of the associated uncoupled structural/cavity modes. An optimal design of structural sensor placement was proposed to achieve sufficiently high modal observability levels for certain important panel-and cavity-controlled modes. Numerical analysis on a panel-cavity system demonstrated the importance of structural sensor placement on virtual sensing and active noise control performance, particularly for cavitycontrolled modes.

Bandwidth widening for sound absorption of a flexible microperforated panel backed by a multi-frequency panel-type resonator

“…Therefore, the backed pressure acting on the MPP, P b ¼ 2:P inc :e iωt where ω is the excitation frequency. The equations of motion for MPP and MPR can be described as (Halim et al, 2011a(Halim et al, , 2011bFahy et al, 2007): i) MPP…”

“…where k g and c g represent the stiffness and damping coefficient of g-th resonator, respectively. The cavities are considered to be rigid-walled rectangular enclosures and acoustic wave equations are expressed as (Halim et al, 2011a(Halim et al, , 2011bFahy et al, 2007): i) Cavity I…”

“…Therefore, the backed pressure acting on the MPP, Pb=2.Pinc.eiωt where ω is the excitation frequency. The equations of motion for MPP and MPR can be described as (Halim et al, 2011a, 2011b; Fahy et al, 2007):i) MPPii) MPRiii) Resonatorswhere ∇4=(∂2∂x2+∂2∂y2)2 and DMPP/MPR=EhMPP/MPR312(1−ν)2 .…”

Structural sensing of interior sound for active control of noise in structural-acoustic cavities

“…It is possible to satisfy the condition of observability of the modes contributing to the frequency range of interest by optimally choosing the locations of a smaller number of sensors. Methods to optimally place the structural sensors (Halim et al, 2011b) can be used in this regard. However, a direct estimation of the structural states would require a number of sensors higher than or at least equal to the number of modes to be estimated.…”

Modelling and development of a robust hybrid rotary-translational vibration energy harvester

“…The development of small, low-cost, ubiquitous sensors (Ukil, 2008) coupled with wireless communications allows data to be gathered simultaneously from numerous locations on a structure with relative ease. The data collected can be used for many purposes, for example (1) improving scientific understanding (Shafer et al, 2015), (2) optimisation (Halim and Cheng, 2014) or (3) condition monitoring (Rajic, 2013). Given the considerable amounts of data that can be collected, the power requirements of the sensor network required to collect the data have come under scrutiny (Halgamuge, 2009).…”