Paper
5 January 1984 A Film By The Aerospace Corp. Showing A Method Of Dynamic Control Of The University Of Texas 7.6m Telescope Primary Mirror
Frank B Ray
Author Affiliations +
Proceedings Volume 0450, Structural Mechanics of Optical Systems I; (1984) https://doi.org/10.1117/12.939273
Event: 1983 Cambridge Symposium, 1983, Cambridge, United States
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.
© (1984) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Frank B Ray "A Film By The Aerospace Corp. Showing A Method Of Dynamic Control Of The University Of Texas 7.6m Telescope Primary Mirror", Proc. SPIE 0450, Structural Mechanics of Optical Systems I, (5 January 1984); https://doi.org/10.1117/12.939273
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KEYWORDS
Mirrors

Aerospace engineering

Telescopes

3D modeling

Data modeling

Feedback control

Finite element methods

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