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Anuradha Annaswamy. Somanath, Amith Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. Massachusetts Institute of Technology. Department of Aeronautics and Astronautics 2010-10-29T18:15:54Z 2010-10-29T18:15:54Z 2010 2010 http://hdl.handle.net/1721.1/59699 668404878 Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2010. Cataloged from PDF version of thesis. Includes bibliographical references (p. 73-75). The thesis develops a new class of adaptive controllers that guarantee global stability in presence of actuation uncertainties. Actuation uncertainties culminate to linear plants with a partially known input matrix B. Currently available multivariable adaptive controllers yield global stability only when the input matrix B is completely known. It is shown in this work that when additional information regarding the structure of B is available, this difficulty can be overcome using the proposed class of controllers. In addition, a nonlinear damping term is added to the adaptive law to further improve the stability characteristics. It is shown here that the adaptive controllers developed above are well suited for command tracking in hypersonic vehicles (HSV) in the presence of aerodynamic and center of gravity (CG) uncertainties. A model that accurately captures the effect of CG shifts on the longitudinal dynamics of the HSV is derived from first principles. Linearization of these nonlinear equations about an operating point indicate that a constant gain controller does not guarantee vehicle stability, thereby motivating the use of an adaptive controller. Performance improvements are shown using simulation studies carried out on a full scale nonlinear model of the HSV. It is shown that the tolerable CG shifts can be almost doubled by using an adaptive controller as compared to a linear controller while tracking reference commands in velocity and altitude. by Amith Somanath. S.M. 75 p. eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Aeronautics and Astronautics. Adaptive control of hypersonic vehicles in presence of actuation uncertainties Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="1aae06d6-f806-4fa7-8f25-963f4aa9466b"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Adaptive control of hypersonic vehicles in presence of actuation uncertainties</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2010</PublicationDate> <Authors> <Author> <DisplayName>Somanath, Amith</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Aeronautics and Astronautics.</Keyword> <Abstract>The thesis develops a new class of adaptive controllers that guarantee global stability in presence of actuation uncertainties. Actuation uncertainties culminate to linear plants with a partially known input matrix B. Currently available multivariable adaptive controllers yield global stability only when the input matrix B is completely known. It is shown in this work that when additional information regarding the structure of B is available, this difficulty can be overcome using the proposed class of controllers. In addition, a nonlinear damping term is added to the adaptive law to further improve the stability characteristics. It is shown here that the adaptive controllers developed above are well suited for command tracking in hypersonic vehicles (HSV) in the presence of aerodynamic and center of gravity (CG) uncertainties. A model that accurately captures the effect of CG shifts on the longitudinal dynamics of the HSV is derived from first principles. Linearization of these nonlinear equations about an operating point indicate that a constant gain controller does not guarantee vehicle stability, thereby motivating the use of an adaptive controller. Performance improvements are shown using simulation studies carried out on a full scale nonlinear model of the HSV. It is shown that the tolerable CG shifts can be almost doubled by using an adaptive controller as compared to a linear controller while tracking reference commands in velocity and altitude.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>