Damping Augmentation of Large Deformable Mirrors for Adaptive Optics

Inhalt:
The recent progresses in large telescopes call for ever larger deformable mirrors for Adaptive Optics. These mirrors tend have lower natural frequencies, which limits the control bandwidth because of control-structure interaction. This paper proposes a strategy to overcome the control-structure interaction by damping augmentation of the vibration modes responsible for it. The approach is illustrated on a numerical model of a deformable mirror actuated by a thick film of piezoelectric material. Two strategies are analyzed: passive and active.