A Predictor-based ADRC for input delay systems subject to unknown disturbances

This paper presents a predictor-based active disturbance rejection control (PADRC) scheme for input delay systems. In the proposed control scheme, the extended state observer (ESO) is modified by delaying the control signal to compensate the time delay from the observation loop. Moreover, a predictor is designed in time domain to obtain estimated states for current time and cancel the effects of input delay on the closed-loop system, where the approximation of disturbances is considered for corrective prediction purposes. Furthermore, a PD controller is designed to compensate disturbances and control the system. Then, the stability of the closed-loop system is analyzed by the Lyapunov function method. Finally, the effectiveness of the PADRC is demonstrated by simulations.