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Proceedings Paper

Application of network control systems for adaptive optics
Author(s): Robert J. Eager
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Paper Abstract

The communication architecture for most pointing, tracking, and high order adaptive optics control systems has been based on a centralized point-to-point and bus based approach. With the increased use of larger arrays and multiple sensors, actuators and processing nodes, these evolving systems require decentralized control, modularity, flexibility redundancy, integrated diagnostics, dynamic resource allocation, and ease of maintenance to support a wide range of experiments. Network control systems provide all of these critical functionalities. This paper begins with a quick overview of adaptive optics as a control system and communication architecture. It then provides an introduction to network control systems, identifying the key design areas that impact system performance. The paper then discusses the performance test results of a fielded network control system used to implement an adaptive optics system comprised of: a 10KHz, 32x32 spatial selfreferencing interferometer wave front sensor, a 705 channel "Tweeter" deformable mirror, a 177 channel "Woofer" deformable mirror, ten processing nodes, and six data acquisition nodes. The reconstructor algorithm utilized a modulo-2pi wave front phase measurement and a least-squares phase un-wrapper with branch point correction. The servo control algorithm is a hybrid of exponential and infinite impulse response controllers, with tweeter-to-woofer saturation offloading. This system achieved a first-pixel-out to last-mirror-voltage latency of 86 microseconds, with the network accounting for 4 microseconds of the measured latency. Finally, the extensibility of this architecture will be illustrated, by detailing the integration of a tracking sub-system into the existing network.

Paper Details

Date Published: 25 March 2008
PDF: 12 pages
Proc. SPIE 6971, Acquisition, Tracking, Pointing, and Laser Systems Technologies XXII, 69710B (25 March 2008); doi: 10.1117/12.776791
Show Author Affiliations
Robert J. Eager, Boeing, AFRL/RDS (United States)

Published in SPIE Proceedings Vol. 6971:
Acquisition, Tracking, Pointing, and Laser Systems Technologies XXII
Steven L. Chodos; William E. Thompson, Editor(s)

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