Stabilization of a Class of Fractional Order Systems With Both Uncertainty and Disturbance

This paper investigates the stabilization problem of fractional order systems with both model uncertainty and external disturbance. By combining the linear feedback control method, the dynamic feedback control method, and the uncertainty and disturbance estimator (UDE)-based control method, respectively, two new UDE-based control methods are developed. Using these methods, the fractional order systems can be stabilized by three steps. In the first step, the linear feedback and dynamic feedback controllers are designed to stabilize the nominal fractional order systems. The second step is to design a UDE-based fractional order controller to estimate the model uncertainty and external disturbance. In the third step, the two controllers are combined into a new controller to realize the stabilization of those fractional order systems. Finally, a numerical example is given to verify the correctness and validity of the proposed methods.