System Identification for Gage Control Property of Strip Rolling Process

Abstract

This paper describes a system identification method on the gage control system of steel rolling. System identification is a useful method for modeling a controlled object to design and tune a high performance controller. However, in online identification during commercial rolling, it is usually difficult to identify exact open loop properties of the system, because the power of the observed signals is relatively small in low frequency, especially in cold rolling. Therefore, we developed an identification algorithm based on auto-regressive moving average model with exogenous input (ARMAX) model to satisfy the specified steady state gain constraint, which is often obtained from the physical model or constants. Furthermore, to remove influence of the causality between input and output signals yielded from feedback gage control, we firstly identified tension response properties using the above new algorithm, and secondly calculated gage control properties by way of interactive model between tension and gage. The effectiveness of the proposed method was demonstrated on the feedforward gage control system of a reversing cold mill.