Publication Date

1992

Document Type

Dissertation/Thesis

First Advisor

Woo, Peng-Yung

Degree Name

M.S. (Master of Science)

Department

Department of Electrical Engineering

LCSH

Adaptive control systems

Abstract

During normal operation, a controlled dynamic process occasionally experiences a change in its physical characteristics due to environmental disturbances. Temperature, pressure or variations in the structure of the process are some common examples of such disturbances. This situation may produce undesirable response and, in severe cases, the stability of the process may be compromised. In order to achieve a desired response in the presence of disturbances, researchers have developed a new class of control systems called adaptive control systems. Many adaptive control systems involve two central process control stages: 1) estimating the time-varying process parameters and 2) modifying the controller's parameters so as to achieve a desired system response. Such schemes include the Model Reference Adaptive Control (MRAC) systems where a model of the controlled process is used to specify the desired performance of the actual process. This work will introduce two new MRAC design approaches to control linear, time-variant systems. In the first approach, the actual controlled process and its model are described by two difference equations. The individual terms of the actual process are equated to the corresponding terms of the model. The unknown process parameters are recursively estimated using the least squares method. From these equations, one can solve for the appropriate controller's parameters that will force the actual process to be consistant with its model. In the second scheme, the controller is designed using the output-to-input relationship. The second scheme updates the controller's parameter values whenever the process parameters change.

Comments

Includes bibliographical references (pages [76]-77)

Extent

vii, 183 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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