Globally stabilizing adaptive control design for nonlinearly-parameterized systems

    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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