Optimized Cross Direction Control of Weight and Porosity, PaperCon '09 Conference

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Providing optimized control of multiple properties on a paper machine requires good independent measurement of each property and a control strategy that can handle cross-couplings. For porosity sensitive grades neither of these requirements has been satisfied, until recently. Now that profiling porosity measurements are available online, it can be combined with the well established benefits of CD multivariable control to deliver truly optimized cross direction control of dry weight and porosity. This paper will review the application of multivariable predictive controls to the cross direction control profiles of dry weight and porosity for cigarette paper and contrast the benefits to a more traditional approach for the controls. The process model of the cigarette paper and the implementation of the CD multivariable controller that resulted in a significant improvement of both reel dry weight and porosity profile at the same time will be discussed.