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Control analysis of the TMT primary segment assembly

Thompson, Peter M. and MacMynowski, Douglas G. and Sirota, Mark J. (2008) Control analysis of the TMT primary segment assembly. In: Ground-based and Airborne Telescopes II. Proceedings of SPIE. No.7012. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 70121N. ISBN 9780819472229. http://resolver.caltech.edu/CaltechAUTHORS:20181112-100309881

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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.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
https://doi.org/10.1117/12.790287DOIArticle
ORCID:
AuthorORCID
MacMynowski, Douglas G.0000-0003-1987-9417
Additional Information:© 2008 Society of Photo-optical Instrumentation Engineers (SPIE). The authors gratefully acknowledge the support of the TMT partner institutions. They are the Association of Canadian Universities for Research in Astronomy (ACURA), the California Institute of Technology and the University of California. This work was supported as well by the Gordon and Betty Moore Foundation, the Canada Foundation for Innovation, the Ontario Ministry of Research and Innovation, the National Research Council of Canada, the Natural Sciences and Engineering Research Council of Canada, the British Columbia Knowledge Development Fund, the Association of Universities for Research in Astronomy (AURA) and the U.S. National Science Foundation.
Group:Thirty Meter Telescope
Funders:
Funding AgencyGrant Number
Association of Canadian Universities for Research in Astronomy (ACURA)UNSPECIFIED
CaltechUNSPECIFIED
University of CaliforniaUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Canada Foundation for InnovationUNSPECIFIED
Ontario Ministry of Research and InnovationUNSPECIFIED
National Research Council of CanadaUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
British Columbia Knowledge Development FundUNSPECIFIED
Association of Universities for Research in Astronomy (AURA)UNSPECIFIED
NSFUNSPECIFIED
Subject Keywords:primary mirror, primary segment assembly, segment support assembly, control structure interaction, control
Record Number:CaltechAUTHORS:20181112-100309881
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20181112-100309881
Official Citation:Peter M. Thompson, Douglas G. MacMynowski, Mark J. Sirota, "Control analysis of the TMT primary segment assembly," Proc. SPIE 7012, Ground-based and Airborne Telescopes II, 70121N (10 July 2008)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:90837
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:13 Nov 2018 18:53
Last Modified:13 Nov 2018 18:53

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