Improvement of adaptive control robustness in presence on unmodeled dynamics

Abstract

New adaptive control laws are proposed that significantly improve the robustness of single-input/single - output plants with unmodeled high frequency dynamics. These laws are based on the introduction of saturation functions in well known adaptive control laws. The corresponding stability analysis is presented and the advantages and limitations of the proposed adaptation scheme are discussed. One major advantage is that global stability properties can be ensured where conventional laws only lead to local stability.