PURPOSE: To restrain the variation in molten metal surface level by estimating disturbance quantity and using a disturbance quantity cancelling control arithmetic part for transmitting a signal for cancelling this quantity and a feedback control quantity arithmetic part for acting so as to match the actual value of the molten metal surface level with the target value.
CONSTITUTION: A first wt. function 54 for making intensity of a transmitting function from the disturbance causing the variation in the molten metal surface level L to a control output of the molten metal surface level low in the desired frequency zone and a second wt. function 56 for making intensity of a transmitting function for this disturbance to before developing the disturbance low in the desired frequency zone are set, respectively. An equation of state and an equation of output by using these wt. functions, control output, control operating quantity and disturbance estimated value as state variables are described. To these equations, an H infinitive control theory is applied and the feedback signal is obtd. and the sum of the signals and a correct signal for cancelling the disturbance is transmitted to an actuator for controlling the flowing quantity (q) of the molten metal into a mold. By this method, the molten metal surface level L is kept stable.
ASANO KAZUYA
KACHI TAKAYUKI
YAMANE AKIRA
WAKATSUKI YUJI
KIMURA HIDENORI
OOTA YOSHIHITO
KIMURA HIDENORI