15th Triennial World Congress of the International Federation of Automatic Control
  Barcelona, 21–26 July 2002 
ADAPTIVE PRE-EMPTIVE CONTROL OF VACUUM DEWATERING IN PAPER MANUFACTURING
Petar Bjegovic*,1 Perry Y. Li*,2
* Department of Mechanical Engineering,
University of Minnesota,
111 Church St. SE,
Minneapolis, MN 55455, U.S.A.
1 Email:petar@me.umn.edu 2Email:pli@me.umn.edu

Paper manufacturing involves the sequential removal of water from pulp by means of gravity, vacuum dewatering, mechanical pressing and thermal drying. Our research aims to propose a new control topology for moisture content using surrogate easurements to infer in-process moisture content, and the pressure settings in the vacuum dewatering section as actuators. This new topology has the potential to overcome the limitations of the current process control topology which has a long dead-time, causes excessive use of the dryers, and hence is limited in performance, robustness and is inefficient in energy usage. A pre-emptive control law was previously proposed for the new topology to decouple the upstream disturbances from propagating downstream. In this paper, we develop an adaptive version of this pre-emptive controller to alleviate the need to know the dewatering coefficients precisely. The adaptive control problem has the interesting aspects that the unknown parameters are nonlinearly embedded in the error dynamics, and there is a time delay before the error in the estimated parameters can be observed.
Keywords: Feedforward, time delay, adaptive control, nonlinear parameterization, paper industry
Session slot T-Th-M02: Time Delay and PID Adaptive Control/Area code 3b : Adaptive Control and Tuning