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An experimental investigation of modeling and optimal control of modified space structures


Moser, Albert N. (1992) An experimental investigation of modeling and optimal control of modified space structures. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/6cyt-4m83.


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Future space missions will rely on structures with many closely spaced and lightly damped modes. To meet the alignment performance requirements of the missions, these structures will need to incorporate active control. Control which does not destabilize the system requires very accurate models of all modes present in a certain bandwidth of the structure's response. Development of the accurate models through system identification is significantly complicated by modes with almost equal frequencies and dampings which appear as single peaks in the structure's frequency response function. Similarly, difficulty in control will be increased by changes in the system due to docking of other systems.

A structure was built at Caltech for identification and control experiments which exhibits many of the features of large space structures. Identification, modification, and control experiments have been conducted on this system to develop optimal controllers which are robust to system changes. This thesis presents the theory and experimental results behind the modeling of modifications on the structure. It also details use of H[...]/[...]-synthesis methods for this problem. Robust controllers have been implemented so as to remove responses of the lowest nine modes of the structure. These controllers perform very well even when the structure is modified by the addition of dynamics.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Major Option:Applied Mechanics
Thesis Availability:Public (worldwide access)
Thesis Committee:
  • Caughey, Thomas Kirk (chair)
Defense Date:13 March 1992
Record Number:CaltechETD:etd-08102005-153952
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3084
Deposited By: Imported from ETD-db
Deposited On:10 Aug 2005
Last Modified:16 Apr 2021 23:08

Thesis Files

PDF (Moser_an_1992.pdf) - Final Version
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