Control analysis of the TMT primary segment assembly

Peter M. Thompson; Douglas G. MacMynowski; Mark J. Sirota

doi:10.1117/12.790287

10 July 2008 Control analysis of the TMT primary segment assembly

Peter M. Thompson, Douglas G. MacMynowski, Mark J. Sirota

Proceedings Volume 7012, Ground-based and Airborne Telescopes II; 70121N (2008) https://doi.org/10.1117/12.790287
Event: SPIE Astronomical Telescopes + Instrumentation, 2008, Marseille, France

Abstract

The primary mirror control system (M1CS) stabilizes the 492 segments of the Thirty Meter Telescope primary mirror in the presence of disturbances. Each Primary Segment Assembly (PSA) has three actuators and position sensors that control the piston, tip, and tilt of the mirror segment. Requirements for the PSA position controller are presented, with the main requirements being 10 Newton per micron stiffness below one Hertz, where wind is the primary disturbance. Bandwidths of the PSA position controller of about twenty Hertz, assuming a soft actuator, are needed to meet this requirement. A finite element model of the PSA was developed and used for a preliminary control design. PSA structural modes at 40, 90, and 120 impact the control design. We have studied control designs with different actuators, sensors, and structural filters in order to assess disturbance rejection properties and interactions with the PSA structural modes. The performance requirements are achieved using voice coil actuators with modal control architecture for piston, tip, and tilt. Force interactions with the underlying mirror cell are important, and we present the status of our studies of the control structure interaction effect (CSIE). A related paper presents further analysis of the CSIE and MICS global position control loop.

Citation Download Citation

Peter M. Thompson, Douglas G. MacMynowski, and Mark J. Sirota "Control analysis of the TMT primary segment assembly", Proc. SPIE 7012, Ground-based and Airborne Telescopes II, 70121N (10 July 2008); https://doi.org/10.1117/12.790287

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