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Proceedings Paper

Servo simulation and modeling for the Gemini 8-m telescopes
Author(s): Michael K. Burns
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Paper Abstract

The Gemini servo simulation is a 6 degree of freedom (6-DOF) time domain simulation which is meant to represent the interaction between the servo controls and the telescope structure. The performance measure is root mean square image motion, based on the translations and rotations of the optical elements. The telescope structural model is based upon a sophisticated finite element analysis (FEA) to include the expected bending and torsional modes. Active control of the secondary mirror is modeled in a realistic way, including delays and noise, in order to show the expected improvement to image smear. Among the error sources for the altitude and azimuth control loops are angular encoder quantization, nonlinear bearing friction, motor D/A quantization, motor torque cogging, drive eccentricity, and tachometer ripple. Other relevant nonlinearities include drive amplifier voltage and current limits. Some other smaller simulations are also included: a simplified model for the tip-tilt response to telescope windshake, a model for azimuth drive slip-suppression, and a simple image-quality simulation.

Paper Details

Date Published: 8 June 1995
PDF: 15 pages
Proc. SPIE 2479, Telescope Control Systems, (8 June 1995); doi: 10.1117/12.211437
Show Author Affiliations
Michael K. Burns, Gemini 8-m Telescopes Project (United States)

Published in SPIE Proceedings Vol. 2479:
Telescope Control Systems
Patrick T. Wallace, Editor(s)

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