VLT 4LGSF OTA field selector mechanism

VLT 4LGSF OTA Field Selector Mechanism 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). 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.

Herkunftsnachweis:

F. Kamphues/TNO/ESO

Über das Bild

ID:tno_kamphues_32
Typ:Fotografisch
Veröffentlichungsdatum:20. März 2012 21:03
Größe:4288 x 2848 px

Über das Objekt

Name:Laser Guide Star
Typ:Unspecified : Technology
Kategorie:Paranal

Bildformate

Großes JPEG
1,1 MB

Skalierbar


Bildschirm-Hintergrundbilder

1024x768
127,8 KB
1280x1024
186,4 KB
1600x1200
249,7 KB
1920x1200
282,9 KB
2048x1536
372,5 KB