H∞ adaptive observer for nonlinear systems with disturbed output

Abstract

This paper presents the design of an adaptive robust observer for a class of nonlinear system considering that the output is affected by a perturbation. The observer is able to estimate the state vector and the value of an unknown parameter present in a system. This allows to reduce the effect of the perturbation in the system output. A Lyapunov-like analysis was performed to guarantee the stability of the observer. The gains are computed by means of LMI and satisfying the performance of the H∞ criterion. The proposed observer is evaluated by estimating the state vector and an unknown parameter of an academic example, reducing considerably the presence of disturbances at the output.