A paper machine color control system design using modern techniques

This paper takes the reader through the steps of a control system design using both optimal control theory and sensitivity analysis. The problem is to control color on a paper machine. The physical aspects of color are briefly described and a model for the paper machine is given. The model responses are compared with responses obtained experimentally on a small-scale machine. The retention turns out to be an unknown and variable parameter. A sampled-data design is carried out for the nominal case where the retention is 100 percent using the linear-regulator theory. A parameter
\rho
weighing the control effort in the quadratic cost function is then used as a design parameter.