Method of controlling hot finish rolling, method of controlling steel sheet, and device for controlling hot finish rolling

Abstract

A method of controlling hot finish rolling, in cooperative control of the hot finish rolling, by controlling a rolling state using an evaluation function in which weight gains are set for each of a plurality of state variables and a plurality of manipulated variables and obtaining control gains that minimize the evaluation function, includes: a step of normalizing the weight gains by a normalization unit; a step of performing, by a comparative evaluation unit, comparative evaluation on the weight gains of the state variables after normalization and performing comparative evaluation on the weight gains of the manipulated variables after normalization; and a step of adjusting, by a gain adjustment unit based on a result of the comparative evaluation, at least one of: the weight gains of the state variables; and the weight gains of the manipulated variables.

1 . A method of controlling hot finish rolling, in cooperative control of the hot finish rolling, by controlling a rolling state using an evaluation function in which weight gains are set for each of a plurality of state variables and a plurality of manipulated variables and obtaining control gains that minimize the evaluation function, the method comprising:
 a step of normalizing the weight gains by a normalization unit included in a computer;   a step of performing, by a comparative evaluation unit included in the computer, comparative evaluation on the weight gains of the state variables after normalization and performing comparative evaluation on the weight gains of the manipulated variables after normalization; and   a step of adjusting, by a gain adjustment unit included in the computer based on a result of the comparative evaluation, at least one of: the weight gains of the state variables;   and the weight gains of the manipulated variables.   
     
     
         2 . The method of controlling hot finish rolling according to  claim 1 , wherein
 the state variables include deviations of actual values with respect to target values of a sheet thickness of a steel sheet, a tension, and a looper angle, and   the manipulated variables include a pressing position of the steel sheet, a main machine speed, and a looper torque.   
     
     
         3 . The method of controlling hot finish rolling according to  claim 1 , further comprising a step of displaying whether or not adjustment of the weight gains in current cooperative control is necessary based on a comparison between a control characteristic of cooperative control in normal condition and a control characteristic of the current cooperative control with a color map by a characteristic monitoring unit included in the computer before adjustment of the weight gains. 
     
     
         4 . The method of controlling hot finish rolling according to  claim 1 , wherein the gain adjustment unit is configured to adjust the at least one of the weight gains of the state variables and the weight gains of the manipulated variables by inputting the result of the comparative evaluation to a machine learning model subjected to be trained in advance by using, as input data, the result of the comparative evaluation and using, as output data, the at least one of the weight gains of the state variables after adjustment and the weight gains of the manipulated variables after adjustment, and causing the machine learning model to output at least one of the weight gains of the state variables after adjustment and the weight gains of the manipulated variables after adjustment. 
     
     
         5 . A method of manufacturing a steel sheet, the method comprising manufacturing a steel sheet by using the method of controlling hot finish rolling according to  claim 1 . 
     
     
         6 . A device for controlling hot finish rolling, in cooperative control of the hot finish rolling, by controlling a rolling state using an evaluation function in which weight gains are set for each of a plurality of state variables and a plurality of manipulated variables and obtaining control gains that minimize the evaluation function, the device comprising:
 a normalization unit configured to normalize the weight gains; 
 a comparative evaluation unit configured to
 perform comparative evaluation on the weight gains of the state variables after normalization, and 
 perform comparative evaluation on the weight gains of the manipulated variables after normalization; and 
 
 a gain adjustment unit configured to adjust, based on a result of the comparative evaluation, at least one of: the weight gains of the state variables; and the weight gains of the manipulated variables. 
 
     
     
         7 . The device for controlling hot finish rolling according to  claim 6 , wherein the gain adjustment unit is configured to adjust the at least one of the weight gains of the state variables and the weight gains of the manipulated variables by inputting the result of the comparative evaluation to a machine learning model subjected to be trained in advance by using, as input data, the result of the comparative evaluation and using, as output data, the at least one of the weight gains of the state variables after adjustment and the weight gains of the manipulated variables after adjustment, and causing the machine learning model to output at least one of the weight gains of the state variables after adjustment and the weight gains of the manipulated variables after adjustment. 
     
     
         8 . A method of manufacturing a steel sheet, the method comprising manufacturing a steel sheet by using the method of controlling hot finish rolling according to  claim 2 . 
     
     
         9 . A method of manufacturing a steel sheet, the method comprising manufacturing a steel sheet by using the method of controlling hot finish rolling according to  claim 3 . 
     
     
         10 . A method of manufacturing a steel sheet, the method comprising manufacturing a steel sheet by using the method of controlling hot finish rolling according to  claim 4 .