Hierarchical anti-disturbance adaptive control for non-linear systems with composite disturbances and applications to missile systems

In this paper, a new anti-disturbance controller is presented for a class of non-linear systems with multiple disturbances. The first part of the disturbance is described by an exogenous model and the second part represents an uncertain variable bounded by a given function. A new non-linear disturbance observer is designed to estimate the composite disturbances. Then, a hierarchical control strategy consisting of disturbance-observer-based control and a robust adaptive controller is presented to achieve the anti-disturbance performance. A stability analysis for both the error estimation systems and the composite closed-loop system is provided. Finally, the approach is applied to a missile control system to show the efficiency of the approach.