On the optimal reconstruction and control of adaptive optical systems with mirror dynamics

• Tipo: Artigo em Revista Científica Internacional
• Data: 2010

Autores

Correia, C (Autor) Outra; Raynaud, HF (Autor) Outra; Kulcsár, C (Autor) Outra; Conan, JM (Autor) Outra

Revista

Título: Journal of the Optical Society of America A: Optics and Image Science, and Vision

Vol. 27

Páginas: 333-349

ISSN: 1084-7529

Editora: Optical Society of America

Indexação

ISI Web of Knowledge - 53 Citações

Scopus - 54 Citações

Outras Informações

ID Authenticus: P-009-F9Z

DOI: 10.1364/josaa.27.000333

Abstract (EN): In adaptive optics (AO) the deformable mirror (DM) dynamics are usually neglected because, in general, the DM can be considered infinitely fast. Such assumption may no longer apply for the upcoming Extremely Large Telescopes (ELTs) with DM that are several meters in diameter with slow and/or resonant responses. For such systems an important challenge is to design an optimal regulator minimizing the variance of the residual phase. In this contribution, the general optimal minimum-variance (MV) solution to the full dynamical reconstruction and control problem of AO systems (AOSs) is established. It can be looked upon as the parent solution from which simpler (used hitherto) suboptimal solutions can be derived as special cases. These include either partial DM-dynamics-free solutions or solutions derived from the static minimum-variance reconstruction (where both atmospheric disturbance and DM dynamics are neglected altogether). Based on a continuous stochastic model of the disturbance, a state-space approach is developed that yields a fully optimal MV solution in the form of a discrete-time linear-quadratic-Gaussian (LQG) regulator design. From this LQG standpoint, the control-oriented state-space model allows one to (1) derive the optimal state-feedback linear regulator and (2) evaluate the performance of both the optimal and the sub-optimal solutions. Performance results are given for weakly damped second-order oscillatory DMs with large-amplitude resonant responses, in conditions representative of an ELT AO system. The highly energetic optical disturbance caused on the tip/tilt (TT) modes by the wind buffeting is considered. Results show that resonant responses are correctly handled with the MV regulator developed here. The use of sub-optimal regulators results in prohibitive performance losses in terms of residual variance; in addition, the closed-loop system may become unstable for resonant frequencies in the range of interest. © 2010 Optical Society of America.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 17