Customization strategies for the solution of linear programming problems arising from large scale model predictive control of a paper machine

This paper presents an application of a customized linear programming (LP) based model predictive control strategy to the paper machine cross directio n (CD) control problem. The objective of CD control is to maintain flat pro files of variables of interest by minimizing worst case deviations from set points (defects). These control problems can have as many as 200 actuators (inputs) and 400 sensor measurements (outputs). This large size coupled wit h the stringent real-time requirement of computing a control move in a few seconds poses a very challenging control problem. Computational results tha t demonstrate the effectiveness of this strategy will be presented. For typ ical disturbances this algorithm can compute provably optimal control moves for a 400 input x 400 output control problem in approximately 5 s versus a pproximately 90 s for a generic LP algorithm on a HP 9000/770 workstation. (C) 1999 Elsevier Science Ltd. All rights reserved.