Comparison of vibration mitigation controllers for adaptive optics systems
Date
2012-07-01
Authors
Guesalaga, Andres
Neichel, Benoit
Rigaut, Francois
Osborn, James
Guzman, Dani
Journal Title
Journal ISSN
Volume Title
Publisher
Optical Society of America
Abstract
Vibrations are detrimental to the performance of modern adaptive optics (AO) systems. In this paper, we describe new methods tested to mitigate the vibrations encountered in some of the instruments of the Gemini South telescope. By implementing a spectral analysis of the slope measurements from several wavefront sensors and an imager, we can determine the frequencies and magnitude of these vibrations. We found a persistent vibration at 55 Hz with others occurring occasionally at 14 and 100 Hz. Two types of AO controllers were designed and implemented, Kalman and H∞, in the multiconjugate AO tip-tilt loop. The first results show a similar performance for these advanced controllers and a clear improvement in vibration rejection and overall performance over the classical integrator scheme. It is shown that the reduction in the standard deviation of the residual slopes (as measured by wavefront sensors) is highly dependent on turbulence, wind speed, and vibration conditions, ranging--in terms of slopes RMS value--from an almost negligible reduction for high speed wind to a factor of 5 for a combination of low wind and strong vibrations.
Description
Keywords
Keywords: Adaptive optics systems; Advanced controller; Slope measurement; Standard deviation; Tip-tilt; Vibration condition; Vibration mitigation; Wave front sensors; Wind speed; Spectrum analysis; Wavefronts; Sensors
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Source
Applied optics
Type
Journal article