Distributed control of a segmented telescope mirror
Date
2010-11-15T23:08:06Z
Authors
Kerley, Dan
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Abstract
As astronomers continue to examine fainter objects and farther back in time, they require increasingly large telescopes due to the fundamental diffraction of optical elements.
Therefore several of the next generation optical telescopes will employ extremely large primary mirrors. However to realistically construct mirrors of these magnitudes they will need to be assembled as a collection of many smaller mirrors. This mirror segmentation leads to the additional challenge of aligning the smaller mirror elements with respect to one another, and maintain that alignment in the presence of disturbances on the optical surface and its supporting structure. To achieve this alignment and disturbance rejection, a complex active control system will be required.
There are several possible solutions to the control problem ranging from fully
decentralized control to a global control scheme. However since many of these
segmented mirrors will be comprised of hundreds of mirror elements a global control
scheme quickly becomes an intractable solution. On the other extreme, a highly scalable decentralized scheme is realizable, however, would lack any global sense of the system. Therefore an appealing solution is a scalable distributed network of controllers, where individual controllers 'act locally' yet 'think globally'. This is achieved by coupling adjacent controller to one another, forming a lattice across the spatial extents of the system.
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Keywords
Telescopes, Mirrors