Grade change predictive control for paper industry

Actually in paper industry, a single paper machine is required to produce many different grades of paper. These grades are distinguished by various paper indicators. The main indicators are the dry content and water content. In a modern production environment, with paper being tailored to the customer´s wishes, the frequency of these grade changes has increased up to the point of multiple changes in a single day. This pushes paper makers to reduce the grade transition time and the waste energy during these transitions. The goal of this research is to study and prototyping techniques able to perform these grade changes. The controller was designed based on Non-Linear Model Predictive Control. The difficulty of the controller design is due to the process to be MIMO with coupled variables and also variable time delay. Moreover the input variables are constrained between upper and lower bounds.