We apply robust control technics to an adaptive optics system including a
dynamic model of the deformable mirror. The dynamic model of the mirror is a
modification of the usual plate equation. We propose also a state-space
approach to model the turbulent phase. A continuous time control of our model
is suggested taking into account the frequential behavior of the turbulent
phase. An H_\infty controller is designed in an infinite dimensional setting.
Due to the multivariable nature of the control problem involved in adaptive
optics systems, a significant improvement is obtained with respect to
traditional single input single output methods