Flexible multibody dynamics and control of the bifocal relay mirror
Approved for public release; distribution is unlimited. === In recent years, spacecraft have become increasingly flexible. The design requirements for the Bifocal Relay Mirror spacecraft include controlling jitter at the nanoradian level. Typically, tight pointing requirements require high structu...
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2012
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ndltd-nps.edu-oai-calhoun.nps.edu-10945-61622015-03-03T15:56:05Z Flexible multibody dynamics and control of the bifocal relay mirror Moore, Brian M. Agrawal, Brij N. Romano, Marcello Naval Postgraduate School (U.S.) Approved for public release; distribution is unlimited. In recent years, spacecraft have become increasingly flexible. The design requirements for the Bifocal Relay Mirror spacecraft include controlling jitter at the nanoradian level. Typically, tight pointing requirements require high structural stiffness, at the cost of increasing the on-orbit mass. To accomplish this, while minimizing the mass of the spacecraft, the structure will have some inherent flexibility. These flexible modes will interact with the pointing control, hence affecting the payload performance. The compensator design conducted in this thesis achieves order of magnitude improvements in controlling the rate error, hence jitter. This thesis starts with a rigid body dynamic model, and develops a flexible body dynamic model. Once the model is developed, the structure-controls interaction is discussed. Finally, compensators are applied to the rigid body controller to mitigate the performance losses present in the flexible body system. Through classical second-order compensators, the angular rate error was decreased by a factor of ten. Nonminimum phase notch filters and phase lag filters were used. Ultimately, the phase lag filters provided the best performance. 2012-03-14T17:47:58Z 2012-03-14T17:47:58Z 2003-12 Thesis http://hdl.handle.net/10945/6162 This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. As such, it is in the public domain, and under the provisions of Title 17, United States Code, Section 105, it may not be copyrighted. Monterey, California. Naval Postgraduate School |
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Approved for public release; distribution is unlimited. === In recent years, spacecraft have become increasingly flexible. The design requirements for the Bifocal Relay Mirror spacecraft include controlling jitter at the nanoradian level. Typically, tight pointing requirements require high structural stiffness, at the cost of increasing the on-orbit mass. To accomplish this, while minimizing the mass of the spacecraft, the structure will have some inherent flexibility. These flexible modes will interact with the pointing control, hence affecting the payload performance. The compensator design conducted in this thesis achieves order of magnitude improvements in controlling the rate error, hence jitter. This thesis starts with a rigid body dynamic model, and develops a flexible body dynamic model. Once the model is developed, the structure-controls interaction is discussed. Finally, compensators are applied to the rigid body controller to mitigate the performance losses present in the flexible body system. Through classical second-order compensators, the angular rate error was decreased by a factor of ten. Nonminimum phase notch filters and phase lag filters were used. Ultimately, the phase lag filters provided the best performance. |
author2 |
Agrawal, Brij N. |
author_facet |
Agrawal, Brij N. Moore, Brian M. |
author |
Moore, Brian M. |
spellingShingle |
Moore, Brian M. Flexible multibody dynamics and control of the bifocal relay mirror |
author_sort |
Moore, Brian M. |
title |
Flexible multibody dynamics and control of the bifocal relay mirror |
title_short |
Flexible multibody dynamics and control of the bifocal relay mirror |
title_full |
Flexible multibody dynamics and control of the bifocal relay mirror |
title_fullStr |
Flexible multibody dynamics and control of the bifocal relay mirror |
title_full_unstemmed |
Flexible multibody dynamics and control of the bifocal relay mirror |
title_sort |
flexible multibody dynamics and control of the bifocal relay mirror |
publisher |
Monterey, California. Naval Postgraduate School |
publishDate |
2012 |
url |
http://hdl.handle.net/10945/6162 |
work_keys_str_mv |
AT moorebrianm flexiblemultibodydynamicsandcontrolofthebifocalrelaymirror |
_version_ |
1716731739207892992 |