Intelligent precise control of rolls contact dynamics in paper manufacturing units

To guarantee final paper grade quality, rolls positioning in paper manufacturing units is a very sensitive parameter as the paper web is pressed in between them during its processing. So their control should be designed in agreement with the strict constraints to be satisfied especially at the end of the process during nip closing operation. The problem is studied from the nonlinear dynamical set of equations representing the phenomenon. It is shown that asymptotic and robust stability of roll position trajectory satisfying system constraints is obtained with a controller which is the sum of a linear PD part and a correcting nonlinear fuzzy one compensating the nonlinear terms in system equations.