METHOD FOR CONTROLLING THICKNESS OF MATERIAL TO BE ROLLED AND DEVICE THEREFOR

PROBLEM TO BE SOLVED: To control the thickness of a material to be rolled with high accuracy by suppressing the generation of delayed control without raising the cost of a device. SOLUTION: With a part 6 for calculating the amount of correction of the screw-down location of the 2nd thickness controller 2, deviations between thicknesses hLPF5 -hLPF7 in which each thickness signal which is passed through a low-pass filter 5 is fetched at a prescribed control period and the target thicknesses h 5 -h 7 are calculated, the 2nd amount of correction of the screw- down location according to PI control, for example, to make the deviations zero is determined and given to adders 8. To each adder 8, the 1st amount of correction of the screw-down location which is calculated to make the deviations between the rolling load and screw-down location given from rolling load measuring devices 34 and screw-down location detectors 32 and the locked-on rolling load and screw-down location zero are given from the 1st thickness controller 1 and, with each adder 8, the 1st amount of correction and 2nd amount of correction are added and given to corresponding screw-down controllers 33.