Performance assessment of a candidate architecture for real-time woofer-tweeter controllers: simulation and experimental results

Norton, Andrew; Gavel, Don; Kupke, Renate; Reinig, Marc; Srinath, Srikar; Dillon, Daren

doi:10.1117/12.2000666

Cited by 3 publications

(3 citation statements)

References 17 publications

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“…The magnetic membrane-based ALPAO mirrors 25 comes with significant development in the actuator count (∼3228) and is driven by low voltage but require high power per actuator (>1 W). 26 Several ground-based observatories [27][28][29][30] have implemented highly efficient deformable secondary mirrors with thin shells driven by voice coil actuators for adaptive optics and high-contrast imaging applications. 30 However, due to the high power needed by these actuators, developing a low-powered prototype with high actuator count (∼1000) is challenging while maintaining other critical performance values, such as surface quality and low rate of actuator failure.…”

Section: Introductionmentioning

confidence: 99%

Demonstration of magnetic and light-controlled actuation of a photomagnetically actuated deformable mirror for wavefront control

et al. 2021

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Deformable mirrors (DMs) have wide applications ranging from astronomical imaging to laser communications and vision science. However, they often require bulky multichannel cables for delivering high power to their drive actuators. A low-powered DM, which is driven in a contactless fashion, could provide a possible alternative to this problem. We present a photomagnetically actuated deformable mirror (PMADM) concept, which is actuated in a contactless fashion by a permanent magnet and low-power laser heating source. We present the laboratory demonstration of prototype optical surface quality, magnetic control of focus, and COMSOL simulations of its precise photocontrol. The PMADM prototype is made of a magnetic composite (polydimethylsiloxane + ferromagnetic CrO 2 ) and an optical-quality substrate layer and is 30.48 mm × 30.48 mm × 175 μm in dimension with an optical pupil diameter of 8 mm. It deforms to 5.76 μm when subjected to a 0.12-T magnetic flux density and relaxes to 3.76 μm when illuminated by a 50-mW laser. A maximum stroke of 8.78 μm before failure is also estimated considering a 3× safety factor. Our work also includes simulation of astigmatism generation with the PMADM, a first step in demonstrating control of higher order modes. A fully developed PMADM may have potential application for wavefront corrections in vacuum and space environments.

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Section: Introductionmentioning

confidence: 99%

Demonstration of magnetic and light-controlled actuation of a photomagnetically actuated deformable mirror for wavefront control

et al. 2021

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“…• A dual-deformable mirror AO pipeline with a 52-actuator, high-stroke, low-frequency (spatial and temporal) ALPAO DM-52 mirror (the "woofer") and a 1024-actuator, low-stroke, high-frequency MEMS Boston Micromachines Kilo-DM mirror (the "tweeter"). 5 The Shack-Hartmann wavefront sensor camera has been upgraded to allow use of a 30×30 lenslet array.…”

Section: Introductionmentioning

confidence: 99%

Swimming with ShARCS: comparison of on-sky sensitivity with model predictions for ShaneAO on the Lick Observatory 3-meter telescope

et al. 2014

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The Lick Observatory's Shane 3-meter telescope has been upgraded with a new infrared instrument (ShARCS -Shane Adaptive optics infraRed Camera and Spectrograph) and dual-deformable mirror adaptive optics (AO) system (ShaneAO). We present first-light measurements of imaging sensitivity in the Ks band. We compare measured results to predicted signal-to-noise ratio and magnitude limits from modeling the emissivity and throughput of ShaneAO and ShARCS. The model was validated by comparing its results to the Keck telescope adaptive optics system model and then by estimating the sky background and limiting magnitudes for IRCAL, the previous infra-red detector on the Shane telescope, and comparing to measured, published results. We predict that the ShaneAO system will measure lower sky backgrounds and achieve 20% higher throughput across the JHK bands despite having more optical surfaces than the current system. It will enable imaging of fainter objects (by 1-2 magnitudes) and will be faster to reach a fiducial signal-to-noise ratio by a factor of 10-13. We highlight the improvements in performance over the previous AO system and its camera, IRCAL.

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“…Woofer and tweeter deformable mirrors from the ShaneAO system along with samples from the natural mode sets of each 12. …”

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Woofer-tweeter deformable mirror control for closed-loop adaptive optics: theory and practice

Gavel¹,

Norton²

2014

SPIE Proceedings

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Deformable mirrors with very high order correction generally have smaller dynamic range of motion than what is required to correct seeing over large aperture telescopes. As a result, systems will need to have an architecture that employs two deformable mirrors in series, one for the low-order but large excursion parts of the wavefront and one for the finer and smaller excursion components. The closed-loop control challenge is to a) keep the overall system stable, b) avoid the two mirrors using control energy to cancel each others correction, c) resolve actuator saturations stably, d) assure that on average the mirrors are each correcting their assigned region of spatial frequency space. We present the control architecture and techniques for assuring that it is linear and stable according to the above criteria. We derived the analytic forms for stability and performance and show results from simulations and on-sky testing using the new ShaneAO system on the Lick 3-meter telescope.

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Performance assessment of a candidate architecture for real-time woofer-tweeter controllers: simulation and experimental results

Cited by 3 publications

References 17 publications

Demonstration of magnetic and light-controlled actuation of a photomagnetically actuated deformable mirror for wavefront control

Demonstration of magnetic and light-controlled actuation of a photomagnetically actuated deformable mirror for wavefront control

Swimming with ShARCS: comparison of on-sky sensitivity with model predictions for ShaneAO on the Lick Observatory 3-meter telescope

Woofer-tweeter deformable mirror control for closed-loop adaptive optics: theory and practice

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