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Proceedings Paper

SPHERES tethered formation flight testbed: application to NASA's SPECS mission
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Paper Abstract

This paper elaborates on theory and experiment of the formation flight control for the future space-borne tethered interferometers. The nonlinear equations of multi-vehicle tethered spacecraft system are derived by Lagrange equations and decoupling method. The preliminary analysis predicts unstable dynamics depending on the direction of the tether motor. The controllability analysis indicates that both array resizing and spin-up are fully controllable only by the reaction wheels and the tether motor, thereby eliminating the need for thrusters. Linear and nonlinear decentralized control techniques have been implemented into the tethered SPHERES testbed, and tested at the NASA MSFC's flat floor facility using two and three SPHERES configurations. The nonlinear control using feedback linearization technique performed successfully in both two SPHERES in-line configuration and three triangular configuration while varying the tether length. The relative metrology system, using the ultra sound metrology system and the inertial sensors as well as the decentralized nonlinear estimator, is developed to provide necessary state information.

Paper Details

Date Published: 24 August 2005
PDF: 13 pages
Proc. SPIE 5899, UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts II, 58990L (24 August 2005); doi: 10.1117/12.614643
Show Author Affiliations
Soon-Jo Chung, Massachusetts Institute of Technology (United States)
Edmund M. Kong, Massachusetts Institute of Technology (United States)
David W. Miller, Massachusetts Institute of Technology (United States)

Published in SPIE Proceedings Vol. 5899:
UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts II
Howard A. MacEwen, Editor(s)

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