Patent ID: 7454253

Claim:
A method of fast approximating the performance of a cross-direction machine-direction multivariable model predictive controller (CDMD MPC) for a spatially-distributed sheet process that comprises the steps of: (a) identifying a process model for the spatially-distributed sheet process which is employed in a sheetmaking machine that forms a sheet of material and that comprises: (i) at least two sets of actuator arrays each distributed adjacent the material in the cross direction (CD), wherein each set of actuator arrays is controllable to vary properties of the material; (ii) means for measuring and acquiring properties data about the properties of the material in the cross direction; (iii) CDMD MPC for the spatially-distributed sheet process providing CD control to the multiple-array cross-directional process, wherein the MPC, in response to signals that are indicative of the properties data, provides signals to the at least two sets of actuator arrays to vary properties of the material; and (iv) means for fast approximating the performance of the CDMD MPC, based on the process model for the spatially-distributed sheet process and tuning parameters and constraints, that includes means for calculating a steady-state spatial performance of the CDMD MPC and means for calculating a dynamic performance of the CDMD MPC; (b) inputting tuning parameters and constraints into the CDMD MPC; (c) calculating steady-state spatial performance for the CDMD MPC for different sheet property modes that includes CD only mode, machine-direction (MD) only mode, and CD and MD mode; (d) calculating a dynamic performance for the CDMD MPC; (e) inputting optimal tuning parameters to the CDMD MPC; and (f) controlling the sheetmaking machine with the CDMD MPC.