ADRC for systems with unobservable and unmatched uncertainty

Abstract

This paper studies the ability of ADRC for systems with unobservable and unmatched uncertainty. First the definition of observability for a class of uncertain nonlinear systems is given and an observability condition is proposed. Then the paper discusses how to transform the unobservable and unmatched uncertainty into the total disturbance, which is both observable and matched, so that the ability of ADRC can be achieved. The effectiveness of ADRC for the unobservable and unmatched uncertainty is shown by the simulations.