In this paper, we apply H∞ control theory to the level-control of a continuous casting machine. The level-control has two major problems of parameter variations and disturbance-pattern variations. In order to cope with these problems, we make up a table which consists of multiple H∞ controllers. By switching one H∞ controller to another properly, adaptability as well as robustness is achieved. This method has been applied to an actual machine and the results show a 40% decrease in level error.
