Patent ID: 8307678

Claim:
A gauge control apparatus which controls a rolled material rolled by a rolling mill to target plate thickness, comprising: top and bottom work rolls which roll the rolled material; top and bottom backup rolls which respectively contact the top and bottom work rolls from above and from below and which are each rotatably supported by an oil film bearing; a load measuring device which measures loads applied to the rolling mill; a gap measuring device which measures a gap between the top and bottom work rolls; a rolling speed measuring device which measures rolling speeds; and an automatic gauge control device which controls the gap to cause plate thickness of the rolled material on a delivery side of the rolling mill to approach the target plate thickness based on a predicted plate thickness calculated using a plate thickness computing expression and the target plate thickness, the automatic gauge control device comprising: an oil film thickness compensation value computing section which computes an oil film thickness compensation value of the gap relative to rolling speeds based on measurement results of the rolling speed measuring device to compensate for increase and decrease of the gap resulting from a change in oil film thicknesses of the oil film bearings, which is attributable to rolling speeds, an acceleration compensation value computing section which computes an acceleration compensation value of plate thickness on the delivery side of the rolling mill relative to rolling speeds based on measurement results of the rolling speed measuring device to compensate for increase and decrease of plate thickness on the delivery side of the rolling mill resulting from a change in deformation resistance of the rolled material which is attributable to rolling speeds, and a deviation computing section which computes deviation of the predicted plate thickness from the target plate thickness based on measurement results of the load measuring device and the gap measuring device, and a mill modulus of the rolling mill, the oil film thickness compensation value, and the acceleration compensation value, which have been computed.