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Title:Nonlinear spline operator interpolation and sliding control of deformable maneuvering bodies
Author(s):Karray, Fakhreddine
Doctoral Committee Chair(s):Dwyer, Thomas A.W., III
Department / Program:Aerospace Engineering
Discipline:Aerospace Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Engineering, Aerospace
Abstract:For purposes of achieving high performances of tracking, and precision pointing of a flexible structure subject to large angular maneuvers (such as the slewing maneuver of a large space structure), a newly developed off-line modeling procedure combined with a robust control technique is investigated and then implemented to the moving structure.
Modeling issue is first discussed, and two different procedures for dealing with the nonlinear dynamics of a given deformable structure are described. The coupled dynamic of vibration, translation and rotation are derived for a completely discretized model and then for a hybrid model.
Deformation estimates are then computed through two types of observers: the well-known extended Kalman filter and the feedback linearized based observer. Knowing that hardware costs, as well as on-time computational problems arise whenever dealing with such observers, especially for high dimensional systems, another alternative is then to be sought.
Indeed, an off-line modeling technique is developed through the theory of nonlinear optimal interpolator. This interpolator is used basically to reduce the dimension of the original system to the one determined by the number of applied test inputs. Estimates of the deformations, as well as error bounds on their measurements are then computed.
Finally, and in order to insure a robust performance of the moving structure subject to induced deformations, and structural parameters variations, a procedure based on the sliding manifolds technique is used. Combination of such a technique, with the outputs of the optimal interpolator constitutes an excellent alternative for the system to achieve robust tracking performances in presence of disturbances and parameter uncertainties. Chattering behavior is avoided at the expense of tolerating a known tracking error margin. It is also shown through the simulations, how a trade-off between the control effort and the tracking error amplitude has to be set by the designer, in order to achieve optimal results.
Issue Date:1989
Rights Information:Copyright 1989 Karray, Fakhreddine
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9010910
OCLC Identifier:(UMI)AAI9010910

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