Mathematical Modelling and Nonlinear Control of a Temper Rolling Mill

This contribution is devoted to the mathematical description of a temper rolling mill and a nonlinear controller design based on physical considerations. The plant consists of a four-high mill stand, unwinder, rewinder, and bridle rolls in the entry and exit section of the mill. Special emphasis is laid on the mathematical modelling of the rollgap, since it establishes the interconnection between the strip tensions, the elongation coefficient, the roll force and the slip conditions. The nonlinear control concept is characterized by the fact that the torques of the bridle rolls are intended as control inputs fo the elongation and master speed control, whereas the hydraulic adjustment system and the main mill drive are used to take effect on the strip tensions.