Anti-disturbance control for nonlinear system via adaptive disturbance observer

This paper addresses the problems of disturbance estimation and anti-disturbance control for nonlinear system with exogenous disturbance, which is generated from an unknown exogenous system. The state observer and the adaptive disturbance observer are designed, simultaneously. Compared with the existing methods, which assumed that the exogenous system parameter matrix was known, our disturbance observer is more applicable in practice. Utilizing the estimation information, an observer-based dynamic output feedback controller is designed, which avoids the influence of output disturbance on the closed-loop system, and contains a disturbance compensation term to compensate the input disturbance. Finally, simulations are provided to demonstrate the effectiveness of the proposed approach. Copyright (c) 2016 John Wiley & Sons, Ltd.