State feedback control of the strip steering for aluminum hot rolling mills

This paper discusses the influence of the various factors on the strip steering, and the new concept of the parallel mill modulus control. It has given an outline of a new steering control system, and has shown its effectiveness. The parallel mill modulus control based on the bending force difference operation is useful in comparison with the conventional control using the roll gap difference operation, because the value of the parallel mill modulus, which depends on the rolling conditions, is not needed. A new steering control system, based on the state feedback using both bending force difference and roll gap difference, has been developed to compensate for the time delay of the actuators and to stabilize steering. By analytically deriving the controller parameters from the plant parameters, tuning of the control system is made easy. The effectiveness of the new system has been shown by application in an actual plant. Copyright (C) 1997 Elsevier Science Ltd.