A metal strip is rolled in a roll stand and a control device for the roll stand determines, by means of a working cycle, a number of manipulated variables for flatness actuators of the roll stand and actuates them accordingly. The control device implements an optimizer, which provisionally sets the current correction values, and determines a totality of flatness values. Then, the optimizer minimizes the relationship by varying the current correction variables. When determining the current correction variables (s), the optimizer considers linear ancillary conditions, based at least in part on a vector having the ancillary conditions upheld by the current correction values and a vector having the ancillary conditions upheld by the difference of the current correction values relative to the correction values of the preceding working cycle. The control device determines the manipulated variables for the flatness actuators in consideration of the determined current correction variables.

A metal strip is rolled in a roll stand and a control device for the roll stand determines, by means of a working cycle, a number of manipulated variables for flatness actuators of the roll stand and actuates them accordingly. The control device implements an optimizer, which provisionally sets the current correction values, and determines a totality of flatness values. Then, the optimizer minimizes the relationship by varying the current correction variables. When determining the current correction variables (s), the optimizer considers linear ancillary conditions, based at least in part on a vector having the ancillary conditions upheld by the current correction values and a vector having the ancillary conditions upheld by the difference of the current correction values relative to the correction values of the preceding working cycle. The control device determines the manipulated variables for the flatness actuators in consideration of the determined current correction variables.