Composite anti disturbance control for a class of uncertain nonlinear systems via a disturbance observer
A new anti disturbance control scheme is proposed for a class of nonlinear systems subjected to multi source disturbances. The uncertain multi source disturbances are classified into two parts; one is the harmonic and constant disturbance with partial known information, which can be formulated by an exogenous system, and the other consists of unknown time varying disturbances. The nonlinear disturbance observer (NDO) is constructed to estimate the first kind of disturbance. By integrating the NDO with an adaptive backstepping technique, a novel composite anti disturbance control scheme is proposed for the nonlinear systems. Then the stability analysis of the closed loop system is presented. The simulation of a numerical example is given to demonstrate the effectiveness of the proposed results.