DIFFERENTIAL TENSION CONTROL WITH OPTIMIZED CONTROLLER DESIGN

摘要

A metal strip (1) is rolled in a rolling mill train. The rolling mill train has a front and a rear rolling stand (2a, 2b), between which a loop lifter (4) is set against the metal strip (1). The loop lifter (4) senses at least one moment (M1, M2) acting on the loop lifter (4) on the drive side and at least one moment (M1, M2) acting on the loop lifter (4) on the operating side. A control device (8) receives the moments (M1, M2) sensed by the loop lifter (4), determines the tension (Z1, Z2) prevailing in the metal strip (1) on the drive side and on the operating side therefrom, and determines the differential tension (δZ) therefrom by difference formation. The control device (8) implements a differential tension controller (12), by means of which the control device (8), using the differential tension (δZ), determines a setting command (S) for a pivoting movement for the front rolling stand (2a) and accordingly controls the front rolling stand (2a). The differential tension controller (12) determines the setting command (S) in such a manner that the setting command (S) has at least one proportional component (SP) proportional to the differential tension (δZ). Above a minimum speed, a ratio between the proportional component (SP) and the differential tension (δZ) is indirectly proportional to a conveying speed (v) at which the metal strip (1) runs out of the front rolling stand (2a).