Experimental active structural acoustic control of simply supported plates using a weighted sum of spatial gradients

Abstract

A limitation currently facing active structural acoustic control (ASAC) researchers is that an ideal minimization quantity for use in the control algorithms has not been developed. A novel parameter termed the "weighted sum of spatial gradients" (WSSG) was recently developed for use in ASAC and shown to effectively attenuate acoustic radiation from a vibrating flat simply supported plate in computer simulations. This paper extends this research from computer simulations and provides experimental test results. The results presented show that WSSG is a viable control quantity and provides better results than the volume velocity approach. The paper also investigates several of the challenges presented by the use of WSSG. These include determining a method to measure WSSG experimentally, an analysis of the influence of noise on WSSG control results and complications presented when degenerate modes exist. Results are shown and discussed for several experimental configurations.

Active control of cylindrical shells using the weighted sum of spatial gradients control metric

“…The spatial uniformity of the V comp cost function contributes to this metric being robust with respect to the error sensor location. In 2014, this method was experimentally validated for a simply supported plate by Hendricks [52]. It was also renamed as the "Weighted Sum of Spatial…”

“…One can see that there is a trade off between spacing the accelerometers closer or farther apart. Hendricks has shown through an optimization process that the optimal distance for reducing these errors is about 1 inch (0.0254 m) [52]. With this configuration, the accelerometer signals are input to the DSP in real time, where finite difference processing is used to obtain the four terms comprising WSSG.…”

Active control of simply supported cylindrical shells using the weighted sum of spatial gradients control metric

“…In subsequent work, this method was implemented on planar structures, and the error metric was referred to as WSSG. [18][19][20][21] This paper presents the extension of the WSSG method to curved structures, and specifically applies the method to a simply supported cylindrical shell, with the objective of fulfilling the criteria mentioned above for practicality and convenience. For curved structures, the membrane and bending stresses are coupled, and this work investigated whether the WSSG method would still work effectively given this difference in the dynamic response.…”

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

“…In the case as acceleration feedback or velocity feedback or displacement, feedback is used independently, equation (14) represents an independent set of equations that can be solved for i or i or i .…”

“…It is clear that in the general ASAC analysis, a quadratic cost function is formed based on the observed pressures, and the quadratic optimization theory is used to find the optimal control inputs that minimize the cost function. 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.…”