Minimum-variance control of astronomical adaptive optic systems with actuator dynamics under synchronous and asynchronous sampling

• Type: Article in International Scientific Journal
• Date: 2011

Authors

Raynaud, HF (Author) Other; Correia, C (Author) Other; Kulcsár, C (Author) Other; Conan, JM (Author) Other

Journal

Title: International Journal of Robust and Nonlinear Control

Vol. 21

Pages: 768-789

ISSN: 1049-8923

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 9 Citations

Scopus - 8 Citations

Other information

Authenticus ID: P-009-FN0

DOI: 10.1002/rnc.1625

Abstract (EN): Adaptive optic (AO) systems are now routinely used in ground-based telescopes to counter the effects of atmospheric turbulence. A deformable mirror (DM) generates a correction wavefront, which is subtracted from the turbulent wavefront using measurements of the residual phase provided by a wavefront sensor (WFS). Minimizing the variance of the residual phase defines a sampled data control problem combining a continuous time minimum-variance (MV) performance criterion with a discrete-time controller. For a fairly general class of linear time-invariant DM and turbulence WFS models, this control problem can be transformed into an equivalent discrete-time LQ optimization problem involving a set of (discrete-time) control-sufficient statistics of the incoming continuous-time turbulence. This paper shows how to constructively solve this MV problem in the presence of DM's dynamics, starting from continuous-time models of DM and turbulence. This result is extended to the case of asynchronous DM/WFS sampling. An illustrative application to optimal control of tip-tilt turbulent modes for the European extremely large telescope in the presence of first-order DM's dynamics is presented. Copyright © 2010 John Wiley & Sons, Ltd.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 22