Multivariable Flatness Control in Multi-High Rolling Mills

Abstract

This paper describes a multivariable algorithm for controlling the flatness of a multi-high rolling mill with actuators of crown control, lateral shift, and tilting rolling. First, the flatness control problem is formulated as a Linear-Quadratic control problem and the control law is derived. Second, to ensure the control constraints are satisfied, a practical flatness control algorithm is proposed. A non-interactive control algorithm is also proposed to compensate for the thickness disturbance caused by the flatness control. Finally, field test results are presented showing the performance of the proposed control algorithms.