A tip/tilt mirror with large dynamic range for the ESO VLT Four Laser Guide Star Facility

N. Rijnveld; R. Henselmans; B. Nijland

doi:10.1117/12.893682

24 September 2011 A tip/tilt mirror with large dynamic range for the ESO VLT Four Laser Guide Star Facility

N. Rijnveld, R. Henselmans, B. Nijland

Proceedings Volume 8125, Optomechanics 2011: Innovations and Solutions; 812503 (2011) https://doi.org/10.1117/12.893682
Event: SPIE Optical Engineering + Applications, 2011, San Diego, California, United States

Abstract

One of the critical elements in the Four Laser Guide Star Facility (4LGSF) for the ESO Very Large Telescope (VLT) is the Optical Tube Assembly (OTA), consisting of a stable 20x laser beam expander and an active tip/tilt mirror, the Field Selector Mechanism (FSM). This paper describes the design and performance testing of the FSM. The driving requirement for the FSM is its large stroke of ±6.1 mrad, in combination with less than 1.5 μrad RMS absolute accuracy. The FSM design consists of a Zerodur mirror, bonded to a membrane spring and strut combination to allow only tip and tilt. Two spindle drives actuate the mirror, using a stiffness based transmission to increase resolution. Absolute accuracy is achieved with two differential inductive sensor pairs. A prototype of the FSM is realized to optimize the control configuration and measure its performance. Friction in the spindle drive is overcome by creating a local velocity control loop between the spindle drives and the shaft encoders. Accuracy is achieved by using a cascaded low bandwidth control loop with feedback from the inductive sensors. The pointing jitter and settling time of the FSM are measured with an autocollimator. The system performance meets the strict requirements, and is ready to be implemented in the first OTA.

Citation Download Citation

N. Rijnveld, R. Henselmans, and B. Nijland "A tip/tilt mirror with large dynamic range for the ESO VLT Four Laser Guide Star Facility", Proc. SPIE 8125, Optomechanics 2011: Innovations and Solutions, 812503 (24 September 2011); https://doi.org/10.1117/12.893682

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available