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Title: Dynamic re-optimization of a spacecraft attitude controller in the presence of uncertainties
Author (s): Unnikrishnan, Nishant
Balakrishnan, S. N.
Padhi, R.
Issue Date: 2006
Publisher: Institute of Electrical and Electronics Engineers
Citation: Unnikrishnan, N.; Balakrishnan, S. N.; Padhi, R. "Dynamic Re-optimization of a Spacecraft Attitude Controller in the Presence of Uncertainties" IEEE International Symposium on Intelligent Control, 2006. Oct. 2006 Pages:452-457
Abstract: Online trained neural networks have become popular in recent years in the design of robust and adaptive controllers for dynamic systems with uncertainties due to their universal function approximation capabilities. This paper discusses a technique that dynamically reoptimizes a Single Network Adaptive Critic (SNAC) based optimal controller in the presence of unmodeled plant uncertainties. The SNAC based optimal controller designed for the nominal plant model no more retains optimality in the presence of uncertainties/unmodeled dynamics that may creep up in the system equations during operation. This calls for a strategy to re-optimize the existing SNAC controller with respect to the original cost function but corresponding to new constraint (state) equations. The controller re-optimization is carried out in two steps: (i) synthesis of a set of online neural networks that capture the uncertainties in the plant equations on-line (ii) reoptimization of the existing SNAC controller to drive the states of the plant to a desired reference by minimizing the original cost function. This approach has been applied in the online reoptimization of a spacecraft attitude controller and numerical results from simulation studies are presented here.
Type: Article - Conference proceedings
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titleDynamic re-optimization of a spacecraft attitude controller in the presence of uncertainties
contributor.authorUnnikrishnan, Nishant
contributor.authorBalakrishnan, S. N.
contributor.authorPadhi, R.
date.issued2006
date.submitted2007
publisherInstitute of Electrical and Electronics Engineers
identifier.citationUnnikrishnan, N.; Balakrishnan, S. N.; Padhi, R. "Dynamic Re-optimization of a Spacecraft Attitude Controller in the Presence of Uncertainties" IEEE International Symposium on Intelligent Control, 2006. Oct. 2006 Pages:452-457
identifier.pub.URI
http://ieeexplore.ieee.org/iel5/4064891/4064892/04064919.pdf?arnumber=406491
description.abstractOnline trained neural networks have become popular in recent years in the design of robust and adaptive controllers for dynamic systems with uncertainties due to their universal function approximation capabilities. This paper discusses a technique that dynamically reoptimizes a Single Network Adaptive Critic (SNAC) based optimal controller in the presence of unmodeled plant uncertainties. The SNAC based optimal controller designed for the nominal plant model no more retains optimality in the presence of uncertainties/unmodeled dynamics that may creep up in the system equations during operation. This calls for a strategy to re-optimize the existing SNAC controller with respect to the original cost function but corresponding to new constraint (state) equations. The controller re-optimization is carried out in two steps: (i) synthesis of a set of online neural networks that capture the uncertainties in the plant equations on-line (ii) reoptimization of the existing SNAC controller to drive the states of the plant to a desired reference by minimizing the original cost function. This approach has been applied in the online reoptimization of a spacecraft attitude controller and numerical results from simulation studies are presented here.
typeArticle - Conference proceedings
type.DCMITypetext
type.statusFinal version
rightsThis material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.
rights.URI
http://www.ieee.org/web/publications/rights/policies.html
date.accessioned2007-04-05T14:28:57Z
date.available2007-04-05T14:28:57Z
identifier.persist.URI
http://scholarsmine.mst.edu/post_prints/04064919_09007dcc8030dc6a.html
Full Text
04064919_09007dcc8030dc6f.pdf