Patent ID: 6289971
Filing Date: 2001-09-18
Classification: B22D

Abstract:
A mold level control apparatus having a mold level detector for detecting a mold level in a mold and outputting a mold level detected value signal indicating a mold level detected value, and controlling a stopper or a sliding gate to maintain constant the mold level in a continuous casting facility, said mold level control apparatus comprising:a control deviation calculating unit for calculating a mold level control deviation by the use of a mold level instruction value signal and the mold level detected value signal, and outputting a mold level control deviation signal indicating the mold level control deviation;a steady-state deviation restraining unit for calculating a mold level steady-state deviation restraining state amount by using the mold level control deviation signal, and outputting a mold level steady-state deviation restraining signal indicating the mold level steady-state deviation restraining state amount;a periodic disturbance restraining unit having a control component oscillated at a frequency equal to a frequency of a periodic disturbance of the mold level, calculating a mold level periodic disturbance restraining state amount by using the mold level control deviation signal, and outputting a mold level periodic disturbance restraining signal indicating the mold level periodic disturbance restraining state amount;a control loop robust stabilization unit supplied with the mold level steady-state deviation restraining signal and the mold level periodic disturbance restraining signal, calculating an operating amount of the stopper or the sliding gate so that a mold level control loop constituted by the mold level control apparatus is brought into robust stability, and outputting an operating amount signal indicating the operating amount; anda periodic disturbance frequency adapting unit supplied with the mold level detected value signal and a casting speed detected value signal and detecting an oscillatory frequency of the mold level as a frequency of the periodic disturbance, and changing calculation characteristics of the periodic disturbance restraining unit and the control loop robust stabilization unit based on a result of the detection.