JPS5758908A - Setting method for roll gap of rolling mill - Google Patents

Abstract

PURPOSE: To set the roll gap at high accuracy and high speed, by controlling a roughly reducing motor correspondingly to a deviation of the actual roll gap from a preset roll gap of a rolling mill, and by sending a command on the cylinder position to a hydraulic cylinder.

CONSTITUTION: The deviation of the roll gap is obtained from a present roll gap RGr sent out of a roll gap setter 38 and an actual roll gap RGf sent out of a roll gap operator 36. A maximum speed command is given to a roughly reducing motor's speed controller 22 until the said deviation becomes lower than the 1st set point. Then, a stepwise slow down command is given to the controller 22 until the deviation becomes lower than the 2nd set point; if the deviation becomes lower than the 2nd set point, a stop command is given to the controller 22. According to thus scheduled timing, a proportional plus integral control expressed by the equation (in which, α is an integral gain and β is a proportional gain) is carried out for obtaining a cylinder's position command which is then given to a hydraulic cylinder's position controller 42. By the present method, highly accurate setting of the roll gap is finished in a short time, and an overshooting is prevented.

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