Title

Globally stabilizing adaptive control design for nonlinearly-parameterized systems

Authors

Authors

Z. H. Qu; R. A. Hull;J. Wang

Comments

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Abbreviated Journal Title

IEEE Trans. Autom. Control

Keywords

adaptive control; certainty equivalence principle; Lyapunov-based; design; nonlinear parameterization; parameter estimation; OUTPUT-FEEDBACK; ROBUST-CONTROL; PLANTS; Automation & Control Systems; Engineering, Electrical & Electronic

Abstract

In this note, a new adaptive control design is proposed for nonlinear systems that are possibly nonaffine and contain nonlinearly parameterized unknowns. The proposed control is not based on certainty equivalence principle which forms the foundation of existing and standard adaptive control designs. Instead, a biasing vector function is introduced into parameter estimate; it links the system dynamics to estimation error dynamics, and its choice leads to a new Lyapunov-based design so that affine or nonaffine systems with nonlinearly parameterized unknowns can be controlled by adaptive estimation. Explicit conditions are found for achieving global asymptotic stability of the state, and the convergence condition for parameter estimation is also found. The conditions are illustrated by several examples and classes of systems. Besides global stability and estimation convergence, the proposed adaptive control has the unique feature that it does not contains any robust control part which typically overpowers unknown dynamics, may be conservative, and also interferes with parameter estimation.

Journal Title

Ieee Transactions on Automatic Control

Volume

51

Issue/Number

6

Publication Date

1-1-2006

Document Type

Article

Language

English

First Page

1073

Last Page

1079

WOS Identifier

WOS:000238660600020

ISSN

0018-9286

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