Control system for cross-directional profile sheet formation

• US 6,026,334 A
• Filed: 07/29/1997
• Issued: 02/15/2000
• Est. Priority Date: 07/30/1996
• Status: Expired due to Fees

• Current Assignee: Weyerhaeuser Company (Weyerhauser)
• Original Assignee: Weyerhaeuser Company (Weyerhauser)
• Inventors: Kayihan, Ferhan, Arkun, Yaman
• Primary Examiner(s): Grant, William
• Assistant Examiner(s): Rapp, Chad
• Application Number:
  US08/902,306
• Time in Patent Office: 931 Days
• Field of Search: 364/471.01, 364/471.02, 364/471.03, 364/469.01, 364/148, 364/149, 364/150, 702/85
• US Class Current: 700/28
• CPC Class Codes: B65H 2801/84 Paper-making machines
• CPC Class Codes: D21G 9/0054 details of algorithms or programs
• CPC Class Codes: G05B 13/042 in which a parameter or coefficient is automatically adjusted to optimise the performance

Abstract

A control system for calculating a number of output control signals for use in a continuous web paper making system. The control system receives a number of input signals from a plurality of sensors and reduces the number of inputs using a singular value decomposition based on a static model of the paper making system. The space of the inputs is further reduced using a principal component analysis of a moving window of values equal to the difference in the sensor values and an output of the static model of the paper making system. Once the space of the inputs is reduced, they are applied to a reduced order control system that calculates a reduced number of output control signals. The outputs of the reduced order control system are a function of the principal component analysis of the data in the moving window. The space of the output control signals is then increased using inverse transformations of the principal component analysis and the singular value decomposition before being applied to a plurality of actuators that control the paper making system.

Claims

1. A control system for controlling the operation of a machine or process, comprising:

a plurality of actuators that receive a set of output control signals in order to control the operation of the machine or process;

a plurality of sensors that produce input sensor signals indicative of the operation of the machine or process;

a processor programmed to produce the control signals from the sensor signals by;

creating an input vector of difference signals by subtracting a number of input sensor signals from a number of output signals created by a fixed model of the machine or process;

storing a sequence of prior input vectors;

reducing the number of input signals produced by the plurality of sensors based on a singular value decomposition of the fixed model of the machine or process and on a principal component analysis of the stored sequence of prior input vectors;

applying the reduced number of input signals to a reduced order controller, that is a function of the principal component analysis to calculate a reduced number of output control signals; and

increasing the number of output control signals based on the principal component analysis of the stored sequence of prior input vectors and the singular value decomposition in order to create the set of output control signal supplied to the actuators.

2. The control system of claim 1, wherein the reduced order control system comprises:

a control algorithm that produces the reduced number of output control signals from the reduced number of input signals;

a reduced order effective process model of the control algorithm that receives the reduced number of output control signals and produces output signals indicative of an expected operation of the machine or process; and

a differencing circuit that determines the difference between the reduced number of input signals and the output signals produced by the reduced order effective process model wherein an output of the differencing circuit is applied as the inputs to the control algorithm.