Robust disturbance rejection for uncertain fractional-order systems

This paper describes a disturbance rejection scheme that adopts equivalent-input-disturbance (EID) approach for uncertain fractional-order (FO) systems. An EID estimator that contains an FO observer is designed to actively compensate for the disturbances and process modeling uncertainties without requiring their prior knowledge. Under the construction of the FO control system, a robust stability condition and the parameters of the controller are derived using a linear matrix inequality based method. Finally, numerical and practical examples are illustrated to demonstrate the validity and superiority of the method.