Application of model predictive control (mpc)-based forced ramping of process input variables and process output reference trajectory design over a prediction horizon for mpc-based paper machine grade change control

Abstract

A controller reference trajectory design technique to enable high-performing automatic grade change performed by a model predictive control (MPC). Techniques include: (1) automatic determination of appropriate process output reference trajectory delays to enable optimum coordination of process input movements; (2) providing the entire planning process output reference trajectory ramp at the start of the grade change instead of just incrementally as the grade change progresses, again enabling movement of the process inputs to drive process outputs along the planned future path instead of just towards the current target; and (3) use of the process input forced ramping to allow linear ramping of process inputs with optimal coordination of other process input movements to keep all process outputs following the desired trajectories. The technical benefits are faster and higher performing grade changes. In addition, the use of this technology allows easier setup and maintenance of the automatic grade change package.