Robust adaptive fault diagnosis approach based on disturbance observer

In this paper, an anti-disturbance fault diagnosis scheme is addressed for a class of systems with both faults and multiple disturbances. The first part of the disturbances is the uncertain modeled disturbances and the second one represents an uncertain variable bounded by an unknown constant. A composite observer with adaptive compensation is designed to estimate the uncertain modeled disturbance and fault simultaneously. Stability analysis for the estimation error system is provided. Finally, simulation is given to show the efficiency of the proposed approach.