ROBUST REPETITIVE CONTROL AND DISTURBANCE REJECTION BASED ON TWO-DIMENSIONAL MODEL AND EQUIVALENT-INPUT-DISTURBANCE APPROACH

A new configuration of a modified repetitive-control system has been devised for a class of strictly proper plants that suppresses exogenous disturbances and uncertainties in the dynamics of the plant. It extends the applicability of the control system. The system consists of four parts: a two-dimensional augmented model of the plant, which takes into account the difference in characteristics between continuous control and discrete learning in repetitive control; an equivalent-input-disturbance estimator; a state observer; and a state-feedback controller. A robust-stability condition expressed in terms of a linear matrix equality is used to determine the gains of the observer and the controller. Finally, a comparison of our method with repetitive control based on linear active disturbance rejection control (LADRC) shows how effective our method is and that it is superior to LADRC-based repetitive control.