Hot rolling process holds a crucial position in modern manufacturing industry as the first process that is used to convert material into finished wrought product. Thus the effect of quality improvement in this process is more impactive than that of other processes. The quality of the products in the process has been mainly focused on the uniform thickness of the plate, and a lot of researches have been made for the control of the thickness in the process. In these days, the quality control of the rolling process is extended to dimensional control, that is both the thickness and the width control. The variation of the thickness and the width of the plate are made by the gap control of the horizontal and the vertical rolls respectively. To control both the width and thickness of the plate, well-combined motion of the horizontal and vertical rolls are needed, since the two-dimensional factors affect each other.
In this paper, the plate dimensional control system for the hot rolling process which consists of AWC(Automatic Width Control), AGC(Automatic Gap Control) using neural network estimator and controller are proposed.
In AWC system, vertical rollers compensate the lateral spread of a slab before it is rolled between two horizontal rolls. For this compensation when a slab enters vertical roller zone, the gap between vertical rollers have to be estimated considering the lateral spread by horizontal rollers. For that, the width estimator using a neural network is built and its performance is evaluated through a series of simulation on the AWC system. To produce the plate with estimated dimension by the vertical rollers, a neural network controller is proposed since the process has the nonlinear characteristics. The neural network controller has the combined structure of ART2 and RBF, which has the self-organizing and adaptive characteristics. The same structure of the controller is applied to the AGC.
A series of simulation shows that neural network estimator and controllers have good performance and produce a plate with uniform thickness and width.
