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K-modification and a novel approach to output feedback adaptive control

This dissertation presents novel adaptive control laws in both state feedback and output feedback forms. In the setting of state feedback adaptive control K-modification provides a tunable stiffness term that results in a frequency dependent filtering effect, smoother
transient responses, and time delay robustness in an adaptive system. K-modification
is combined with the recently developed Kalman filter (KF) based adaptive control and
derivative-free (DF) adaptive control. K-modification and its combinations with KF adaptive
control and DF adaptive control preserve the advantages of each of these methods and
can also be combined with other modification methods such as - and e-modification. An
adaptive output feedback control law based on a state observer is also developed. The main
idea behind this approach is to apply a parameter dependent Riccati equation to output
feedback adaptive control. The adaptive output feedback approach assumes that a state
observer is employed in the nominal controller design. The observer design is modified
and employed in the adaptive part of the design in place of a reference model. This is
combined with a novel adaptive weight update law. The weight update law ensures that
estimated states follow both the reference model states and the true states so that both
state estimation errors and state tracking errors are bounded. Although the formulation is
in the setting of model following adaptive control, the realization of the adaptive controller
uses the observer of the nominal controller in place of the reference model to generate an
error signal. Thus the only components that are added by the adaptive controller are the
realizations of the basis functions and the weight adaptation law. The realization is even
less complex than that of implementing a model reference adaptive controller in the case of
state feedback. The design procedure of output feedback adaptive control is illustrated with
two examples: a simple wingrock dynamics model and a more complex aeroelastic aircraft
transport model.

Identiferoai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/39579
Date04 April 2011
CreatorsKim, Kilsoo
PublisherGeorgia Institute of Technology
Source SetsGeorgia Tech Electronic Thesis and Dissertation Archive
Detected LanguageEnglish
TypeDissertation

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