METHOD AND APPARATUS FOR CONTROLLING LEVEL OF MOLTEN METAL SURFACE IN MOLD OF CONTINUOUS CASTING MACHINE

PROBLEM TO BE SOLVED: To provide a method and an apparatus for controlling the level of a molten metal surface in a mold of a continuously casting machine which enables fluctuation in a level of a molten metal surface caused by bulging under regular casting to be reduced, and thereby realize the highly accurate control in the level of the molten metal surface. SOLUTION: Since a pinch roll torque signal changes around a certain load, only fluctuating frequency components are extracted with a band-pass filter or the like. Concretely, the fluctuating frequency in a molten metal surface of a specified cycle is detected from a molten metal surface level signal, and a filtration treatment of extracting detected molten metal fluctuating frequency components from the pinch roll torque signal is performed. Next, from the phase characteristics between the pinch roll torque and the molten metal surface level and the phase characteristics between uc and y as the objects for control, the phase angles to be delayed are found and is subjected to phase adjustment, and it is matched to the phase with which disturbance can be offset. Finally, a suitable adjustment gain is multiplied to reverse code, and it is added to the output from a PI controller. COPYRIGHT: (C)2006,JPO&NCIPI