| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent induction of vibration, to reduce a loss in operation and thereby to improve productivity by executing a control of elevation of a movable electrode by using a controlling computation formula for negating natural vibration characteristics by an inverse model of either a hydraulic cylinder or a mechanical structure or both of them. SOLUTION: A voltage between a movable electrode and a furnace bottom electrode is detected by an arc voltage detector 30, proportional-plus-integral computation is executed by a voltage regulator 32 so that a deviation of the detected voltage from a set voltage predetermined be zero, and an operation output thus obtained is supplied to hydraulic equipment for an elevation control. The hydraulic equipment makes a control valve of a hydraulic circuit operate in accordance with a control signal. A height of an oil column changes in conformity with dynamic characteristics 41 of the oil column, a mechanical structure fitted to a hydraulic cylinder is moved up and down and the movable electrode supported by the mechanical structure is moved up and down therewith. Herein an inverse model 64 of a dynamic characteristic model of the oil column is provided in a vibration suppression circuit 60 and the dynamic characteristics 41 of the oil column is negated by the inverse model 64 of the dynamic characteristic model of the oil column in a control system as a whole.</p> |
