Full LQG control with vibration mitigation: from theory to first on-sky validation on the CANARY MOAO demonstrator

Sivo, Gaetano; Kulcsár, Caroline; Conan, Jean-Marc; Raynaud, Henri-François; Gendron, É.; Basden, Alastair; Vidal, Fabrice; Morris, Tim; Meimon, Serge; Petit, Cyril; Gratadour, Damien; Martin, Olivier; Hubert, Z.; Rousset, G.; Dipper, N. A.; Talbot, Gordon; Younger, Eddy; Myers, R

doi:10.1364/aopt.2013.otu2a.2

Cited by 10 publications

(8 citation statements)

References 7 publications

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“…The next step was to demonstrate full LQG control on-sky, full meaning with optimal LQG control of all modes, and not only tip and tilt. This paper presents a detailed analysis of the first SCAO on-sky validation of a full LQG control with vibration mitigation, performed in July and August 2012 [22,23]. We compare performance obtained with integrator versus LQG, with and without vibration mitigation.…”

Section: Introductionmentioning

confidence: 99%

First on-sky SCAO validation of full LQG control with vibration mitigation on the CANARY pathfinder

Sivo¹,

Kulcsár²,

Conan³

et al. 2014

Opt. Express

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107

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Adaptive optics provides real time correction of wavefront disturbances on ground based telescopes. Optimizing control and performance is a key issue for ever more demanding instruments on ever larger telescopes affected not only by atmospheric turbulence, but also by vibrations, windshake and tracking errors. Linear Quadratic Gaussian control achieves optimal correction when provided with a temporal model of the disturbance. We present in this paper the first on-sky results of a Kalman filter based LQG control with vibration mitigation on the CANARY instrument at the Nasmyth platform of the 4.2-m William Herschel Telescope. The results demonstrate a clear improvement of performance for full LQG compared with standard integrator control, and assess the additional improvement brought by vibration filtering with a tip-tilt model identified from on-sky data, thus validating the strategy retained on the instrument SPHERE at the VLT.

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Section: Introductionmentioning

confidence: 99%

First on-sky SCAO validation of full LQG control with vibration mitigation on the CANARY pathfinder

Sivo¹,

Kulcsár²,

Conan³

et al. 2014

Opt. Express

Self Cite

107

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show abstract

“…3. At this phase of CANARY, onsky demonstration of tomographic wavefront reconstruction using artificial neural networks was first demonstrated (Osborn et al 2014), together with first demonstration of tomographic LQG control (Sivo et al 2013). …”

Section: Fourmentioning

confidence: 99%

Experience with wavefront sensor and deformable mirror interfaces for wide-field adaptive optics systems

Basden

Atkinson

Bharmal

et al. 2016

Mon. Not. R. Astron. Soc.

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Recent advances in adaptive optics (AO) have led to the implementation of wide field-of-view AO systems. A number of wide-field AO systems are also planned for the forthcoming Extremely Large Telescopes. Such systems have multiple wavefront sensors of different types, and usually multiple deformable mirrors (DMs).Here, we report on our experience integrating cameras and DMs with the real-time control systems of two wide-field AO systems. These are CANARY, which has been operating on-sky since 2010, and DRAGON, which is a laboratory adaptive optics realtime demonstrator instrument. We detail the issues and difficulties that arose, along with the solutions we developed. We also provide recommendations for consideration when developing future wide-field AO systems.

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“…The standard deviation of the measurement noise, as well as r 0 and L 0 , have been taken from the specifications of the CANARY project [9], [37], [36], [34]; this project consists in a small-scale demonstrator for the E-ELT, so the intensity of the measurement noise that we have assumed can be considered as representative of current technology.…”

Section: B First Test: Ar1 Turbulence Modelmentioning

confidence: 99%

An Approximation of the Riccati Equation in Large-Scale Systems With Application to Adaptive Optics

Massioni

Raynaud

Kulcsár

et al. 2015

IEEE Trans. Contr. Syst. Technol.

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The problem of finding linear optimal controllers and estimators, like linear quadratic regulators (LQRs) or Kalman filters, is solved by means of a matrix Riccati equation. A bottleneck of such an approach is that the numerical solvers for this equation are computationally intensive for systems with a high number of states, making it difficult if not impossible to apply optimal (minimum-variance) control and/or estimation methods to large-scale systems. A specific example is adaptive optics (AO) systems for the next generation of extremely large telescopes, for which the number of states to be estimated by a Kalman filter is in the order of the tens of thousands, making the numerical solution of the Riccati equations problematic. In this article, we show that for a special class of state-space systems, the discrete-time algebraic Riccati equation can be simplified with an approximation which leads to a closed-form solution, which can be computed more quickly and used as an alternative to standard numerical solvers. The class of systems for which this approximation holds includes a class of models widely employed in AO, namely autoregressive models of order 1 or 2 (AR1, AR2). We verify a posteriori the accuracy and applicability of the proposed solution.

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Full LQG control with vibration mitigation: from theory to first on-sky validation on the CANARY MOAO demonstrator

Cited by 10 publications

References 7 publications

First on-sky SCAO validation of full LQG control with vibration mitigation on the CANARY pathfinder

First on-sky SCAO validation of full LQG control with vibration mitigation on the CANARY pathfinder

Experience with wavefront sensor and deformable mirror interfaces for wide-field adaptive optics systems

An Approximation of the Riccati Equation in Large-Scale Systems With Application to Adaptive Optics

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