Modeling And Control Of Magnetic Fluid Deformable Mirrors For Adaptive Optics Systems

Author : Zhizheng Wu
Publisher : Springer Science & Business Media
ISBN 13 : 3642322298
Total Pages : 323 pages
Book Rating : 4.97/5 ( download)

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Download or read book Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems written by Zhizheng Wu and published by Springer Science & Business Media. This book was released on 2012-10-22 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems presents a novel design of wavefront correctors based on magnetic fluid deformable mirrors (MFDM) as well as corresponding control algorithms. The presented wavefront correctors are characterized by their linear, dynamic response. Various mirror surface shape control algorithms are presented along with experimental evaluations of the performance of the resulting adaptive optics systems. Adaptive optics (AO) systems are used in various fields of application to enhance the performance of optical systems, such as imaging, laser, free space optical communication systems, etc. This book is intended for undergraduate and graduate students, professors, engineers, scientists and researchers working on the design of adaptive optics systems and their various emerging fields of application. Zhizheng Wu is an associate professor at Shanghai University, China. Azhar Iqbal is a research associate at the University of Toronto, Canada. Foued Ben Amara is an assistant professor at the University of Toronto, Canada.

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ISBN 13 :
Total Pages : pages
Book Rating : 4.11/5 ( download)

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Download or read book Modeling and Control of a Magnetic Fluid Deformable Mirror for Ophthalmic Adaptive Optics Systems written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics (AO) systems make use of active optical elements, namely wavefront correctors, to improve the resolution of imaging systems by compensating for complex optical aberrations. Recently, magnetic fluid deformable mirrors (MFDM) were proposed as a novel type of wavefront correctors that offer cost and performance advantages over existing wavefront correctors. These mirrors are developed by coating the free surface of a magnetic fluid with a thin reflective film of nano-particles. The reflective surface of the mirrors can be deformed using a locally applied magnetic field and thus serves as a wavefront corrector. MFDMs have been found particularly suitable for ophthalmic imaging systems where they can be used to compensate for the complex aberrations in the eye that blur the images of the internal parts of the eye. However, their practical implementation in clinical devices is hampered by the lack of effective methods to control the shape of their deformable surface. The research work reported in this thesis presents solutions to the surface shape control problem in a MFDM that will make it possible for such devices to become integral components of retinal imaging AO systems. The first major contribution of this research is the development of an accurate analytical model of the dynamics of the mirror surface shape. The model is developed by analytically solving the coupled system of fluid-magnetic equations that govern the dynamics of the surface shape. The model is presented in state-space form and can be readily used in the development of surface shape control algorithms. The second major contribution of the research work is a novel, innovative design of the MFDM. The design change was prompted by the findings of the analytical work undertaken to develop the model mentioned above and is aimed at linearizing the response of the mirror surface. The proposed design also allows for mirror surface deflections that are many times higher than those provided by.

Author : Azhar Iqbal
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.49/5 ( download)

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Download or read book Modeling and Control of a Magnetic Fluid Deformable Mirror for Ophthalmic Adaptive Optics Systems written by Azhar Iqbal and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Author : Mohsen Sheikholeslami Kandelousi
Publisher : BoD – Books on Demand
ISBN 13 : 1789238374
Total Pages : 246 pages
Book Rating : 4.72/5 ( download)

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Download or read book Nanofluid Flow in Porous Media written by Mohsen Sheikholeslami Kandelousi and published by BoD – Books on Demand. This book was released on 2020-08-19 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies of fluid flow and heat transfer in a porous medium have been the subject of continuous interest for the past several decades because of the wide range of applications, such as geothermal systems, drying technologies, production of thermal isolators, control of pollutant spread in groundwater, insulation of buildings, solar power collectors, design of nuclear reactors, and compact heat exchangers, etc. There are several models for simulating porous media such as the Darcy model, Non-Darcy model, and non-equilibrium model. In porous media applications, such as the environmental impact of buried nuclear heat-generating waste, chemical reactors, thermal energy transport/storage systems, the cooling of electronic devices, etc., a temperature discrepancy between the solid matrix and the saturating fluid has been observed and recognized.

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ISBN 13 :
Total Pages : 180 pages
Book Rating : 4.52/5 ( download)

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Download or read book Advances in Bioengineering written by and published by . This book was released on 2007 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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ISBN 13 :
Total Pages : 180 pages
Book Rating : 4.62/5 ( download)

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Download or read book Advances in Bioengineering--2006 written by and published by . This book was released on 2007 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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ISBN 13 :
Total Pages : 16 pages
Book Rating : 4.91/5 ( download)

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Download or read book The Simplest Test of Target Zone Credibility written by and published by . This book was released on 1990 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Author : David J. Anderson
Publisher :
ISBN 13 :
Total Pages : 363 pages
Book Rating : 4.33/5 ( download)

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Download or read book LQG Control of a Deformable Mirror Adaptive Optics System with Time- Delayed Measurements written by David J. Anderson and published by . This book was released on 1991 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis proposes a linear quadratic Gaussian (LQG) control law for a ground-based deformable mirror adaptive optics system. The incoming image wavefront is distorted, primarily in phase, due to the turbulent effects of the earth's atmosphere. The adaptive optics system attempts to compensate for the distortion with a deformable mirror. A Hartman wavefront sensor measures the degree of distortion in the image wavefront. The measurements are input to a Kalman filter which estimates the system states. The state estimates are processed by a linear quadratic regulator which generates the appropriate control voltages to apply to the deformable mirror actuators. The dynamics model for the atmospheric phase distortion consists of 14 Zernike coefficient states; each modeled as a first-order linear time-invariant shaping filter driven by zero-mean white Gaussian noise. The dynamics of the deformable mirror are also model as 14 Zernike coefficients with first-order deterministic dynamics. A significant reduction in total wavefront phase distortion is achieved in the presence of time-delayed measurements. Wavefront sensor sampling rate is the major factor limiting system performance. The Multimode Simulation for Optimal Filter Evaluation (MSOFE) software is the performance evaluation tool of choice for this research.

Author : William D. Cowan
Publisher :
ISBN 13 : 9781423560623
Total Pages : 285 pages
Book Rating : 4.20/5 ( download)

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Download or read book Foundry Microfabrication of Deformable Mirrors for Adaptive Optics written by William D. Cowan and published by . This book was released on 1998-04-01 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microelectromechanical Systems (MEMS) is a rapidly emerging field of research in which batch fabrication processes are used to construct miniature devices. MEMS devices are particularly well suited to optical applications. Foundry microfabrication offers a substantial cost advantage for prototype system development. In this research, foundry MEMS processes are used to fabricate low-cost deformable mirror systems (MEM-DMs) for adaptive optics. The challenges and design trades associated with fabrication of continuous and segmented deformable mirrors in foundry processes are examined in detail. Micromirror surface figure is shown to be critically important. Beam steering and optical aberration correction experiments conclusively demonstrate the potential of low-cost MEM-DMs. The prototype MEM-DM systems are approximately 1/ 500th the cost of conventionally manufactured deformable mirrors. An innovative direct digital control scheme further reduces adaptive optic system cost by eliminating the digital to analog converter typically required for each controlled element. In addition to the MEM-DMs, other MEMS devices are shown. The thermally actuated piston micromirrors offer greater deflections for operation at longer optical wavelengths. Other MEMS devices examined include a series of tilting mirrors, pressure gauges, test structures, electrostatic scratch drive actuated rotors, and a new type of electrostatic cantilever motor with lateral motion output.

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ISBN 13 :
Total Pages : 1016 pages
Book Rating : 4.32/5 ( download)

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Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1016 pages. Available in PDF, EPUB and Kindle. Book excerpt: