Simulation of segmented mirrors with adaptive optics

Abstract This work deals with the simulation-based investigation and control of optical systems that are mechanically influenced. Here, the focus is on the dynamic-optical modeling of vibration-sensitive, segmented mirror systems, which are used, for example, in large astronomic telescopes. Furthermore, an adaptive optical unit usually compensates for the optical aberrations due to atmospheric disturbances. In practice, these aberrations are detected and corrected within a few seconds using deformable mirrors. However, to further improve the performance of these optical systems, dynamic disturbances in the mechanics, i.e. small movements and deformations of the optical surfaces, must also be taken into account. For the investigation of such cases, multidisciplinary simulation methods are developed and presented.

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Automatic Control Systems for Adaptive Optical Systems. Analytical review. Part 2: Application of the Adaptive Filtering and Control at the Spaced Frequencies

Mechanical Engineering and Computer Science ◽

10.24108/0418.0001342 ◽

2018 ◽

pp. 13-31

Author(s):

Yu. I. Shanin ◽

A. V. Chernykh

Keyword(s):

Adaptive Optics ◽

Adaptive Filtering ◽

Free Stream ◽

Signal Transmission ◽

Low Frequency ◽

Optical Systems ◽

Free Stream Turbulence ◽

Automatic Control Systems ◽

Analytical Review ◽

And Control

The second part of the analytical review considers in detail an adaptive filtering application in the systems of adaptive optical systems (AOS) from the perspective of the airborne laser platforms. Herein the AOS operates under aero-optical distortions and vibrations, which further complicate the propagation of the laser beam. Adaptive filtering is considered as a way to improve the efficiency of the control system of adaptive optical systems, allowing to improve running an adaptive optics control loop: by 1.5-2 times with compensation for only the aero-optical disturbances, by 1.5 times with compensation only for the free-stream turbulence, and by 2.5-3.5 times for the combination of aero-optics and free-stream turbulence.The article discusses implementation of a new type of the controller, which uses intellectual algorithms to predict (through an artificial neural network) a short-term horizon of evolution of aberrations due to aero-optical effect. This controller allows us to deal with a large time delay in signal transmission (up to 5 time steps of sampling).The application of two deformable mirrors in the adaptive optical system to provide control at the spaced frequencies is especially considered. A low-frequency mirror is used to correct the lower-order aberrations (tip-tilt, defocusing, astigmatism, coma) requiring large strokes of executive mechanisms (actuators) in the deformable mirror. A high-frequency mirror is used to correct the higher-order aberrations requiring small strokes of drives. Various control algorithms to control the system from two adaptive mirrors are briefly reviewed.The obtained results, conclusions, and recommendations are supposedly to be used in development of specification of requirements for systems of adaptive optics.

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Adaptive optics with adaptive filtering and control

Proceedings of the 2004 American Control Conference ◽

10.23919/acc.2004.1384398 ◽

2004 ◽

Author(s):

Yu-Tai Liu ◽

S. Gibson

Keyword(s):

Adaptive Optics ◽

Adaptive Filtering ◽

And Control

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A Tip–Tilt and Piston Detection Approach for Segmented Telescopes

Photonics ◽

10.3390/photonics8010003 ◽

2020 ◽

Vol 8 (1) ◽

pp. 3

Author(s):

Shun Qin ◽

Wai Kin Chan

Keyword(s):

Error Detection ◽

Phase Retrieval ◽

Dynamic Range ◽

Detection Accuracy ◽

Wavefront Sensing ◽

Next Generation ◽

Large Aperture ◽

Detection Approach ◽

Segmented Mirror ◽

And Control

Accurate segmented mirror wavefront sensing and control is essential for next-generation large aperture telescope system design. In this paper, a direct tip–tilt and piston error detection technique based on model-based phase retrieval with multiple defocused images is proposed for segmented mirror wavefront sensing. In our technique, the tip–tilt and piston error are represented by a basis consisting of three basic plane functions with respect to the x, y, and z axis so that they can be parameterized by the coefficients of these bases; the coefficients then are solved by a non-linear optimization method with the defocus multi-images. Simulation results show that the proposed technique is capable of measuring high dynamic range wavefront error reaching 7λ, while resulting in high detection accuracy. The algorithm is demonstrated as robust to noise by introducing phase parameterization. In comparison, the proposed tip–tilt and piston error detection approach is much easier to implement than many existing methods, which usually introduce extra sensors and devices, as it is a technique based on multiple images. These characteristics make it promising for the application of wavefront sensing and control in next-generation large aperture telescopes.

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A micromirror array with annular partitioning for high-speed random-access axial focusing

Light Science & Applications ◽

10.1038/s41377-020-00420-6 ◽

2020 ◽

Vol 9 (1) ◽

Author(s):

Nathan Tessema Ersumo ◽

Cem Yalcin ◽

Nick Antipa ◽

Nicolas Pégard ◽

Laura Waller ◽

...

Keyword(s):

Adaptive Optics ◽

Visual Information ◽

High Speed ◽

Random Access ◽

General Purpose ◽

Phase Shifting ◽

Optical Systems ◽

Piston Motion ◽

Refresh Rate ◽

Circular Symmetry

Abstract Dynamic axial focusing functionality has recently experienced widespread incorporation in microscopy, augmented/virtual reality (AR/VR), adaptive optics and material processing. However, the limitations of existing varifocal tools continue to beset the performance capabilities and operating overhead of the optical systems that mobilize such functionality. The varifocal tools that are the least burdensome to operate (e.g. liquid crystal, elastomeric or optofluidic lenses) suffer from low (≈100 Hz) refresh rates. Conversely, the fastest devices sacrifice either critical capabilities such as their dwelling capacity (e.g. acoustic gradient lenses or monolithic micromechanical mirrors) or low operating overhead (e.g. deformable mirrors). Here, we present a general-purpose random-access axial focusing device that bridges these previously conflicting features of high speed, dwelling capacity and lightweight drive by employing low-rigidity micromirrors that exploit the robustness of defocusing phase profiles. Geometrically, the device consists of an 8.2 mm diameter array of piston-motion and 48-μm-pitch micromirror pixels that provide 2π phase shifting for wavelengths shorter than 1100 nm with 10–90% settling in 64.8 μs (i.e., 15.44 kHz refresh rate). The pixels are electrically partitioned into 32 rings for a driving scheme that enables phase-wrapped operation with circular symmetry and requires <30 V per channel. Optical experiments demonstrated the array’s wide focusing range with a measured ability to target 29 distinct resolvable depth planes. Overall, the features of the proposed array offer the potential for compact, straightforward methods of tackling bottlenecked applications, including high-throughput single-cell targeting in neurobiology and the delivery of dense 3D visual information in AR/VR.

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Data fusion and simulation-based planning and control in cyber physical system for digital assembly of aeroplane

International Journal of Modeling Simulation and Scientific Computing ◽

10.1142/s1793962315500270 ◽

2015 ◽

Vol 06 (03) ◽

pp. 1550027 ◽

Cited By ~ 1

Author(s):

Hui Li ◽

Linxuan Zhang ◽

Tianyuan Xiao ◽

Jietao Dong

Keyword(s):

Data Fusion ◽

Hybrid Control ◽

Sliding Mode ◽

Estimation Algorithm ◽

Asynchronous Sampling ◽

Planning And Control ◽

Adaptive Sliding Mode Controller ◽

Simulation Based ◽

And Control ◽

Distributed Fusion

This paper introduces a CPS application for intelligent aeroplane assembly. At first, the CPS structure is presented, which acquires the characteristics of general CPS and enables "simulation-based planning and control" to achieve high level intelligent assembly. Then the paper puts forward data fusion estimation algorithm under synchronous and asynchronous sampling, respectively. The experiment shows that global optimal distributed fusion estimation under synchronized sampling proves to be closer to the actual value compared with ordinary weighted estimation, and multi-scale distributed fusion estimation algorithm of wavelet under asynchronous sampling does not need time registration, it can also directly link to data, and the error is smaller. This paper presents hybrid control strategy under the circumstance of joint action of the inner and outer loop to address the problems caused by the less controllable feature of the parallel mechanism when undertaking online process simulation and control. A robust adaptive sliding mode controller is designed based on disturbance observer to restrain inner interference and maintain robustness. At the same time, an outer collaborative trajectory planning is also designed. All the experiment results show the feasibility of above proposed methods.

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A New Design of Large Stroke Micro-Deformable Mirror Actuated by Electrostatic Repulsive Force

2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems ◽

10.1115/micronano2008-70058 ◽

2008 ◽

Cited By ~ 1

Author(s):

Fangrong Hu ◽

Jun Yao ◽

Chuankai Qiu ◽

Dajia Wang

Keyword(s):

Electric Field ◽

Resonant Frequency ◽

Adaptive Optics ◽

Bottom Electrode ◽

Sacrificial Layer ◽

Electrostatic Force ◽

Repulsive Force ◽

Deformable Mirror ◽

Optical Aberrations ◽

Out Of Plane

In this paper, a MEMS mirror actuated by an electrostatic repulsive force has been proposed and analyzed. The mirror consists of four U-shape springs, a fixed bottom electrode and a movable top electrode, there are many comb fingers on the edges of both electrodes. When the voltage is applied to the top and bottom electrodes, an asymmetric electric field is generated to the top movable fingers and springs, thus a net electrostatic force is produced to move the top plate out of plane. This designed micro-mirror is different from conventional MDM based on electrostatic-attractive-force, which is restricted by one-third thickness of the sacrificial layer for the pull-in phenomenon. The characteristic of this MDM has been analyzed, the result shows that the resonant frequency of the first mode is 8 kHz, and the stroke reaches 10μm at 200V, a MDM with large strokes can be realized for the application of adaptive optics in optical aberrations correction.

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Simulationsbasierte Optimierung von Fabrikabläufen*/Simulation-based optimization of factory processes

wt Werkstattstechnik online ◽

10.37544/1436-4980-2018-04-27 ◽

2018 ◽

Vol 108 (04) ◽

pp. 221-227

Author(s):

T. Donhauser ◽

L. Baier ◽

T. Ebersbach ◽

J. Franke ◽

P. Schuderer

Keyword(s):

Calcium Silicate ◽

Optimization Approach ◽

Process Technology ◽

High Quality ◽

Decomposition Approach ◽

Planning And Control ◽

Simulation Based ◽

Simulation Based Optimization ◽

And Control

Die Kalksandsteinherstellung weist aufgrund prozesstechnisch und zeitlich divergierender Teilprozesse einen hohen Planungs- sowie Steuerungsaufwand auf. Durch Einsatz eines simulationsgestützten Optimierungsverfahrens kann diese Komplexität bewältigt werden. Um bei hoher Lösungsqualität eine Laufzeit zu erreichen, die einen operativen Einsatz des Verfahrens gestattet, wird auf Basis einer vorangegangenen Studie ein Dekompositionsansatz implementiert und dessen Eignung durch Testläufe validiert.   Calcium silicate masonry production requires a great deal of planning and control due to the fact that subprocesses vary in terms of process technology and time. To overcome this complexity, a simulation-based optimization approach is applied. As a short runtime that allows the method to be used operationally and yet still offers a high quality of solution is crucial, a decomposition approach is implemented on the basis of a previous study and its suitability is validated by means of test runs.

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Extreme Adaptive Optics

Annual Review of Astronomy and Astrophysics ◽

10.1146/annurev-astro-081817-052000 ◽

2018 ◽

Vol 56 (1) ◽

pp. 315-355 ◽

Cited By ~ 16

Author(s):

Olivier Guyon

Keyword(s):

Adaptive Optics ◽

Thermal Emission ◽

Contrast Ratio ◽

Angular Separation ◽

Circumstellar Disks ◽

Spectroscopic Characterization ◽

Central Star ◽

High Contrast ◽

Direct Imaging ◽

Segmented Mirror

Over the last two decades, several thousand exoplanets have been identified, and their study has become a high scientific priority. Direct imaging of nearby exoplanets and the circumstellar disks in which they form and evolve is challenging due to the high contrast ratio and small angular separation relative to the central star. Exoplanets are typically within 1 arcsec of, and between 4 and 10 orders of magnitude fainter than, the stars they orbit. To meet these challenges, ground-based telescopes must be equipped with extreme adaptive optics (ExAO) systems optimized to acquire high-contrast images of the immediate surrounding of nearby bright stars. Current ExAO systems have the sensitivity to image thermal emission from young massive planets in near-IR, while future systems deployed on Giant Segmented Mirror Telescopes will image starlight reflected by lower-mass rocky planets. Thanks to rapid progress in optical coronagraphy, wavefront control, and data analysis techniques, direct imaging and spectroscopic characterization of habitable exoplanets will be within reach of the next generation of large ground-based telescopes.

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