Adaptive Optics Feedback Control

UMR 7293, Lagrange Université de Nice Sophia-Antipolis/CNRS/Observatoire de la Côte d’Azur, Parc Valrose, 06108 Nice Cedex 2, France

Abstract

This paper concentrates on the control aspects of Adaptive Optics (AO) systems and includes a prior exposure to linear control systems from the “classical” point of view. The AO control problem is presented and the well-established optimized modal gain integral control approach is discussed. The design of a controller from a modern control point of view is addressed by means of a linear quadratic Gaussian control methodology. The proposed approach emphasizes the ability of the adaptive optics loop to reject the atmospheric aberration. We derive a diagonal state space system which clearly separates the dynamics of the plant (deformable mirror & wavefront sensor) from the disturbance dynamics (atmospheric model). This representation facilitates the numerical resolution of the problem. A frequency analysis is carried out to check performance and robustness specifications of the multiple-input multiple-output feedback system. The effectiveness of the approach is demonstrated through numerical experiments.