A repetitive control system of a model following type

A repetitive control system of the model-following type is proposed. The model that the system output should track is introduced. The dynamic system that represents the tracking error behavior can be considered to be driven by periodic disturbances, and the repetitive control can be applied to this dynamic system. Highly accurate tracking is attained, since the dynamic behavior can be adjusted and the disturbance signals driving the error dynamics can be extremely small. It is shown that a state observer is effective in the case in which there are inaccessible state variables, although the observer can not estimate the exact states of a system as t approaches ∞. The results are applied to repetitive motion control by a DC servomotor