Abstract: A new two-dimensional (2D) variation modeling and control technique for a machine producing a web of material, such as paper, uses functional transformation with basis functions which are wavelets, preferably wavelets derived from and closely resembling the responses generated by actuation of cross direction (CD) actuators of the machine. By using the disclosed functional transformation together with carefully selected basis functions, memory and real-time processing requirements are substantially reduced so that practical controls can be readily implemented. In addition, the functional transformation technique of the present application expands conventional CD correction to also correct for a portion of the residual variations which, until now, have remained uncorrected. The new 2D profile is treated as the superposition of two main components: a pure machine direction (MD) variation component and a two-dimensional sheet variation component.

Abstract: Sensors are spaced along an extended process from its beginning end to its finishing end. Each sensor is associated with a parallel inferential control loop (PICL) and generates an actual measurement signal for a portion of the process. Each PICL includes a process model emulating the sensed portion of the process with the process models being cascaded from the beginning end through and including the finishing end. Each PICL generates a loop control signal corresponding to its sensed portion of process with the loop control signals from the PICLs being summed to generate a total control signal which controls a control element at the beginning end of the process and also is received by the first or most up-stream process model. The process models produce expected measurement signals which are combined with the actual measurement signals to determine difference signals for each PICL which includes a reset model emulating the sensed portion of the process.

Abstract: A standard control signal for a web forming machine is temporarily interrupted and replaced by a perturbing signal or signgals which are applied to one, a grouping, or all of a series of actuation cells of the web forming machine. One or more actuation cells are driven with an alternating perturbing signal(s) which generate a corresponding action in the actuation cell(s). The perturbing signal(s) alternates from a neutral position of the cell and is selected to minimize means effects over any given period of time. The effects of the alternating signal(s) on the web appear within the area of the web which is affected by the actuation cell(s) such that the mapping and the response of the actuation cell(s) can be determined by monitoring that poriton of the web which is formed while the alternating signal(s) is applied to the actuation cell(s).