Date of Award

Summer 2008

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Electrical and Computer Engineering

First Advisor

Yaz, Edwin

Second Advisor

Schneider, Susan

Third Advisor

Josse, Fabien

Abstract

In this thesis, a new method for designing controllers is developed from a combination of control design methods which are already in use; here they are put together to achieve a new, more efficient design method. The goal of controllers designed using this new method is to match a system's transfer function to a corresponding optimal transfer function. A specific performance index, the ITAE, is used as a guide in designing control parameters which will achieve optimization in the initial design of a controller. The use of the ITAE-matching method improves on existing design schemes by eliminating guesswork, and by guaranteeing specific system responses. To alter the system's transfer function to match the ITAE-optimized transfer function for a step response, several steps are taken. First, state-variable feedback is used to alter the locations of the system's poles. If the original system is type 0, an integrator is then added into the system to increase the type number to 1 and to ensure zero steadystate error for a step input. Next, precompensation is used to alter the zeros and gain of the transfer function. Finally, the controller design is completed with unity gain feedback. The implementation of the proposed control design for two cases, a mass-spring-damper system and a magnetic levitation system, demonstrates that the new design method works as expected for linear, time-invariant, single-input, single-output systems. In addition, an examination of the controlled system's robustness demonstrates that the new control method works for nonlinear systems, as well as for systems with unmodeled dynamics, parameter perturbations, or external disturbances.

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