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.

In a method for operating a machine having a trajectory determined by a parts program and including multiple block transitions with a non-tangential contour, a high trajectory speed and a short operating time are achieved. For a first position-controlled axis, an acceleration duration different from a first period duration can be specified, wherein a transition maximum speed for the first position-controlled axis is determined such that, when the first position-controlled axis moves with the transition maximum speed and the transition maximum acceleration is applied, the speed of the first position-controlled axis has a value of zero at the end of the acceleration duration. The traversing movement is determined such that the speed of the first position-controlled axis, at the transition from a first trajectory section to a second trajectory section, does not exceed the transition maximum speed.