Optimal [H-2] and [H-infinity] control of extremely large segmented telescopes

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Title: Optimal [H-2] and [H-infinity] control of extremely large segmented telescopes
Author: Kassas, Zaher
Abstract: Extremely large telescopes (ELTs ) are the next generation of ground -based reflecting telescopes of optical wavelengths . ELTs possess an aperture of more than 20 meters and share a number of common features , particularly the use of a segmented primary mirror and the use of adaptive optics systems . In 2005 , the European Southern Observatory introduced a new giant telescope concept , named the European Extremely Large Telescope (E -ELT ) , which is scheduled for operation in 2018 . The E -ELT will address key scientific challenges and will aim for a number of notable firsts , including discovering Earth -like planets around other stars in the ``habitable zones'' where life could exist , attempting to uncover the relationship between black holes and galaxies , measuring the properties of the first stars and galaxies , and probing the nature of dark matter and dark energy . In 2009 , a feasibility study , conducted by National Instruments , proved the feasibility of the real -time (RT ) control system architecture for the E -ELT's nearly 1 ,000 mirror segments with 3 ,000 actuators and 6 ,000 sensors . The goal of the RT control system was to maintain a perfectly aligned field of mirrors at all times with a loop -time of 1 ms . The study assumed a prescribed controller algorithm . This research report prescribes the optimal controller algorithms for large segmented telescopes . In this respect , optimal controller designs for the primary mirror of the E -ELT , where optimality is formulated in the [H -2] and [H -infinity] frameworks are derived . Moreover , the designed controllers are simulated to show that the desired performance metrics are met .
URI: http : / /hdl .handle .net /2152 /ETD -UT -2010 -08 -1618
Date: 2011-01-04


Optimal [H-2] and [H-infinity] control of extremely large segmented telescopes. Master's thesis, University of Texas at Austin. Available electronically from http : / /hdl .handle .net /2152 /ETD -UT -2010 -08 -1618 .

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