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Proceedings Paper

A Film By The Aerospace Corp. Showing A Method Of Dynamic Control Of The University Of Texas 7.6m Telescope Primary Mirror
Author(s): Frank B Ray
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Paper Abstract

In an application of computer graphics, finite element analysis, and servo control theory, this film is part of the development of an engineering tool for studying the active control of the University of Texas 7.6m telescope primary mirror. The mirror is modelled as a ULE meniscus 0.12m thick. A sinusoidal forcing function is applied to a finite element model, and control software by Dr. R. D. Hefner at Aerospace supplies correction forces in real time to the model. The data displayed are (1)a moving three dimensional plot of the finite element mesh, with its collimating points and actuating points delineated, (2)an rms figure error, (3)an intensity plot of the image formed by the mirror surface, and (4)a plot of the encircled energy at various concentration lev-els. Rate damping is used as the inner loop of control, using velocity feedback data from the model, and an output feedback algorithm after a method by Kosut[1] is used for the outer loop. There are 36 actuation points used for the surface error control. The control software uses the first ten natural modes of vibration of the meniscus.

Paper Details

Date Published: 5 January 1984
PDF: 6 pages
Proc. SPIE 0450, Structural Mechanics of Optical Systems I, (5 January 1984); doi: 10.1117/12.939273
Show Author Affiliations
Frank B Ray, The University of Texas (United States)

Published in SPIE Proceedings Vol. 0450:
Structural Mechanics of Optical Systems I
Lester M. Cohen, Editor(s)

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