Active H-infinity control of sound radiation from thin cylindrical panels

Active control of sound radiated by thin-walled cylindrical panels using arrays of spatially discrete piezoelectric sensors and actuators is addressed. A new general methodology for the design of controllers to reduce structure radiated noise is presented. The methodology utilizes finite element modeling to perform structural discretization. The structure dynamics model, presented in state-space form, incorporates simplified models of the piezoelectric sensing and actuation and accounts for the mass and stiffness of the piezoelectric elements. The acoustic power radiated by the structure into the far field is expressed as a quadratic form of the system states that is used to define an acoustic performance criterion in an H-infinity disturbance rejection controller design setup. The methodology is applied for active control of sound radiated by a vibrating thin cylindrical panel excited by a persistent external force. The controller performance is evaluated using numerical simulations of the controlled structure. It is shown that the sound radiated by the panel into the far field is effectively controlled and reduced. (Author)