Mittag-Leffler stabilization for an unstable time-fractional anomalous diffusion equation with boundary control matched disturbance

This paper addresses the Mittag-Leffler stabilization for an unstable time-fractional anomalous diffusion equation with boundary control subject to the control matched disturbance. The active disturbance rejection control (ADRC) approach is adopted for developing the control law. A state-feedback scheme is designed to estimate the disturbance by constructing two auxiliary systems: One is to separate the disturbance from the original system to a Mittag-Leffler stable system and the other is to estimate the disturbance finally. The proposed control law compensates the disturbance using its estimation and stabilizes system asymptotically. The closed-loop system is shown to be Mittag-Leffler stable and the constructed auxiliary systems in the closed loop are proved to be bounded. This is the first time for ADRC to be applied to a system described by the fractional partial differential system without using the high gain. © 2019 John Wiley & Sons, Ltd.