Clustered Active Structural Acoustic Control in a Rectangular Enclosure

Abstract

The purpose of this paper is reduction of noise in a rectangular enclosure. A rectangular enclosure is considered that five acoustically rigid walls and a flexible plate. Four microphones are symmetrically set in an enclosure, and four point actuators are symmetrically set on a flexible plate. At first, calculating four microphones' outputs organically, acoustic modes are modulated into four acoustic clusters, which have orthogonality among acoustic clusters (acoustic cluster filtering). Then, driving four actuators organically, structural modes are modulated into “four structural clusters”, which have orthogonality among structural clusters (structural cluster actuation). Moreover, it is revealed that orthogonality is also effective between acoustic clusters and structural clusters, and the specific structural/acoustic interaction is termed “cluster coupling”. Finally, integrating acoustic cluster filtering, structural cluster actuation and cluster coupling, C-ASAC (Clustered Active Structural Acoustic Control) system is constructed. C-ASAC consists of SISO virtually due to orthogonality which clusters hold, so that CPU load in C-ASAC is much lighter than a conventional MIMO.