Reduced-Order Generalized Extended State Observer Based Control for Discrete-Time Systems

This paper investigates the controller design problem for discrete-time systems with mismatched disturbances. Firstly, to reject the phase lag in generalized extended state ob-server (GESO) estimation, a reduced-order generalized extended state observer (RGESO) is recommended. It is shown that an RGESO based control can effectively deal with the redundancy problem and reduce the system order via utilizing available states. Finally, a numerical example as well as speed control for an DC motor servo system under proposed method are studied, both of which demonstrate the feasibility and validity.