Nonlinear Adaptive Control with Persistent Disturbances

Abstract

In this paper, we develop a Direct Model Reference Adaptive Tracking Controller for nonlinear systems. This controller can also reject bounded disturbances of known wave form but unknown amplitude, e.g. steps or sinusoids. We prove that the controller produces local asymptotic tracking with bounded controller gains when the linearized open-loop plant is almost strictly positive real (equivalently, is minimum phase and has CB positive definite) and the nonlinear part of the plant is locally Lipschitz continuous. An illustrative example is provided.