US 10,309,059 B2Granted

Method of designing model predictive control for cross directional flat sheet manufacturing processes to guarantee temporal robust stability and performance

AssigneeHoneywell International Inc.

InventorsNing He, Xiaotao Liu, Michael Forbes, Johan Backstrom, Tongwen Chen

Life of this patent

Estimating the term…

Loading patent…

Abstract

Automated parameter tuning techniques for cross-directional model predictive control for paper-making under user-specified parametric uncertainties are developed. The CD-MPC design explicitly accounts for parametric model uncertainty while finding a value for the CD profile trajectory generation that minimizes the CD settling time of the measurement 2 sigma spread and does not exceed an overshoot limit for actuator 2 sigma spread. The inventive technique includes: (i) providing uncertainty specifications for the temporal parameters of the process model, (ii) specifying 2 sigma overshoot limits for the CD actuator profile, (iii) using robust stability theory to find a minimum bound for the profile trajectory tuning parameter, (iv) using a frequency domain technique to reduce the search range for the profile trajectory tuning parameter, and (v) performing an intelligent search for the tuning parameter that minimizes measurement 2 sigma settling time without exceeding the actuator 2 sigma overshoot limit.

Claims20

Dependent claims

A system which forms a material in a spatially-distributed multivariable-array cross-directional process wherein the system comprises:

at least one set of actuator arrays each distributed adjacent to the material in cross direction (CD), wherein each set of actuator arrays is controllable to vary properties of the material;
a scanning sensor for measuring and acquiring properties data about the properties of the material;
and
a multivariable model predictive controller (MPC) providing CD control of the CD process, wherein the MPC, in response to signals that are indicative of the properties of the material, provides signals to the at least one set of actuator arrays to control properties of the material, wherein the MPC includes an interface to allow a processing device to receive:
nominal temporal model parameters and corresponding parametric uncertainty specifications;
and
a specified worst-case 2 sigma (2σ) overshoot limit for a CD actuator profile;
for temporally tuning the MPC, the processing device is configured to:
(a) develop a robust temporal stability condition based on the parametric uncertainty specifications;
(b) calculate a lower bound for a profile trajectory tuning parameter that assures robust stability, comprising;
generating a reference trajectory using a temporal filter comprising a parameter;
and
calculating a lower bound for the profile trajectory tuning parameter using an automatic tuning algorithm;
(c) reduce a possible range of the tuning parameter by using a frequency domain technique;
and
(d) perform an intelligent search for the tuning parameter that minimizes worst-case measurement 2σ settling time without exceeding the actuator worst-case 2σ overshoot limit.

13 more elements

Dependencies are inferred from the claim text.