Smart panels for active structural acoustic control

This paper presents a theoretical study comparing sound transmission through different kinds of smart panels, comprising an aluminium plate, of dimensions 247 mm × 278 mm ×1 mm, with various kinds of embedded structural sensors and actuators. The analysis is focused on systems using simple single-channel feedback controllers, so that self-contained, compact and light sensor–controller–actuator devices can be built. Initially, two idealized smart panels have been studied: first, a panel with a volume velocity sensor and a collocated uniform force actuator pair, connected via a single-channel fixed gain feedback control; and second, a panel with sixteen collocated point velocity sensors and point force actuators each controlled in a decentralized fashion by a single-channel fixed gain feedback control system. The control effectiveness obtained with ideal sensor and actuator systems has also been contrasted with those of more realistic devices, in which the sensing system is made either of a large piezoelectric distributed film or an array of point velocity transducers, and the actuation is given either by a large piezoelectric film or an array of small piezoelectric patches. The control effectiveness, stability and robustness of each control configuration have been discussed. Also, some practical problems related to the construction of the smart panels have been briefly described.