Robust adaptive unknown input observer design for a class of disturbed systems

Abstract

This paper proposes a novel approach for designing a robust adaptive unknown input observer (UIO) for a class of nonlinear system. The system is composed of nonlinear terms and exogenous disturbance and fault signals which are considered to be unknown. The main contribution of the paper is to present the UIO system that uses adaptive law and linear matrix inequality (LMI). Adaptive law is used for system current fault estimation and LMI is used to provide the feasible set of responses while ensuring system stability. The effectiveness of the proposed method is shown by applying to the numerical examples. The simulation results show the validity of this method for a nonlinear system with unknown upper bound disturbance.