Modeling, approximation and H∞/MinMax periodic control in structural acoustic models: numerical implementation and computational results

Dr. Michael Demetriou

Department of Mathematics
Boise State University

February 27, 1997

Abstract

A feedback control computational methodology for reducing acoustic sound pressure levels in a 3-D cavity with a flexible boundary (a circular plate) is investigated. The control is implemented in this model through voltages to piezoceramic patches on the plate which are excited in a manner (out-of-phase) so as to produce pure blending moments. The incorporation of the output feedback control in this system leads to a problem with unbounded input and output terms. By writing the resulting system as an abstract Cauchy equation, the problem of reducing interior pressure levels can be posed in the context of an H∞ / MinMax time domain state space formulation. A summary of extensive computational efforts comparing output feedback with full state feedback, investigating the effect of the number and location of sensors on performance of the control, and the numerical/algebraic effects of certain solutions of operator/matrix Riccati equations on the control performance is presented.