Improvement of transient response of vibrating secondary mirror of Infrared Astronomy Telescope (IRAT)

Raja Vel Sethupathi

doi:10.1117/12.176162

1 June 1994 Improvement of transient response of vibrating secondary mirror of Infrared Astronomy Telescope (IRAT)

Raja Vel Sethupathi

Proceedings Volume 2199, Advanced Technology Optical Telescopes V; (1994) https://doi.org/10.1117/12.176162
Event: 1994 Symposium on Astronomical Telescopes and Instrumentation for the 21st Century, 1994, Kailua, Kona, HI, United States

Abstract

In this work, the problem of improving the transient response of a vibrating secondary mirror of IRAT with square input is considered. The secondary mirror held at the focus of the cassegrainian primary mirror of the telescope is vibrated at different frequencies so as to separate the signal from the background noise and other disturbances. However classical transient response problems put a limitation to the frequency with which the secondary mirror can be vibrated. Conventional PID tuning controllers are designed to minimize system transient errors, but it is not implemented due to the space limitation in the vicinity of the secondary mirror. Hence, another scheme, called Posicast control, which involves only modification of the input signal, is designed and implemented. The transient response is found to improve drastically allowing the output to reach steady-state in a much shorter time. The control has been designed and presented in a look-up table for all frequencies of vibration and for all amplitude levels, thereby effective tracking of distant celestial objects is made possible.

Citation Download Citation

Raja Vel Sethupathi "Improvement of transient response of vibrating secondary mirror of Infrared Astronomy Telescope (IRAT)", Proc. SPIE 2199, Advanced Technology Optical Telescopes V, (1 June 1994); https://doi.org/10.1117/12.176162

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KEYWORDS

Mirrors

Telescopes

Space telescopes

Control systems

Astronomical telescopes

Computing systems

Infrared astronomy

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