SHEET SHAPE CONTROL METHOD FOR ROLLING MILL

PURPOSE:To facilitate the control of a sheet shape dealing with a detection delay and the response delay of an actuator with high stability and high responsiveness by estimating the value of the disturbance to be corrected with respective adjusting devices while compensating the detection delay of a shape parameter from the shape parameter and the detected change value of rolling load. CONSTITUTION:A load cell 8, etc., are provided on a rolling mill 4 to detect the change: P of the rolling load thereof. The strain distribution: f(chi, t) in the transverse direction of a sheet is first calculated in accordance with the tension distribution value: sigma(chi) in the transverse direction detected by a sensor roll 6. The share parameter : LAMBDAyi (i: the number of the actuators used for shape control) is computed from this value and the detection delay of the sensor roll 6. This LAMBDAyi is the parameter to express a sheet shape defect. The disturbance to generate the sheet shape defect to be applied on the rolling mill 4 is estimated from the resulted shape parameter: LAMBDAyi and the change value: P of the rolling load detected by the above-mentioned load cell 8. The respective actuators are operated to control the shape of the rolled sheet in accordance with such estimated value of the disturbance.