Modeling and Control of Fiber Orientation in Papermaking Machines

Abstract

An algorithm for online control of the fiber orientation angle obtained in paper machines was developed. The control algorithm utilizes local linear models reflecting the change in fiber orientation angle as a function of the edge flow rates and slice bolt adjustments of the head box. These local linear models were derived from the results of fluid simulations based on the nonlinear Navier-Stokes equation. By the steepest descent method, we obtained the control algorithm that optimizes the estimate function calculated from these local linear models. The control algorithm was incorporated in the computer control system of an actual paper machine, and significant improvement in productivity and paper quality over extended operation has been realized.