Adaptive Regulation of Nonlinear Systems with Unmodeled Dynamics

Conditions are given for global stability of an adaptive control law designed for the reduced order model of a class of higher order nonlinear plants. In the presence of unmodeled dynamics. which account for the difference between the model and the plant, the regulation property is preserved in a stability region. The size of the region is estimated via a set of bounds that not only proves robustness, but also allows a comparison between adaptive and nonadaptive nonlinear controls.