Model – based control of front – end bending in hot rolling processes ⋆

This contribution deals with the modeling and control of flatness defects in form of so–called ski–ends which occur during the hot rolling process of heavy plates. These ski–ends are caused by asymmetrical rolling conditions, e.g., different work roll circumferential speeds or vertical temperature gradients. In a first step, a physics–based model for asymmetrical rolling is derived based on the upper bound method for ideal rigid–plastic materials and is validated by means of numerical and measurement data. It turns out that the drive train proves to be the suitable actuator for suppressing the ski–ends. Therefore, an improved underlying multi–input multi–output control concept for the two main drives is presented. Finally, an overall pass–to– pass model–based control concept for the reduction of ski–ends is developed. Copyright c © 2008 IFAC