Feedback controllers for active vibration suppression

The aim of the present paper is to investigate two strategies for the active control of plate vibrations, using distributed sensors and actuators (PVDF patches) working on a wide frequency band. The two strategies correspond to the two ends of a spectrum ranging from very robust/less efficient schemes (analog static output feedback) to less robust/very efficient schemes (here ‘frequency shaped LQG’). Both have been experimentally tested and have given successful attenuations; the efficiency of both approaches is demonstrated on sensor signals involved in the control loop as well as on radiated pressure measurements, which constitute an independent index of performance. It is shown that ‘frequency shaped LQG’ is a viable approach to feedback control of lightly damped structures, and that its robustness can be enhanced through a careful design. LQG is a model-based method, and hence requires the modeling of the active structure. Two approaches are investigated in this paper: a finite element model and a identified model built from the experimentally measured transfer functions.