US 7,653,445 B2Granted

Apparatus and method for model-based control

AssigneeControlSoft, Inc.

InventorsTien-Li Chia, Irving Lefkowitz, Coleman B. Brosilow, Alireza Haji-Valizadeh, Shahid Parvez, John T. Nagle

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Abstract

Various methods and systems for the parametric control of a process include representing the process with a process model used to generate future predictions of a process variable. In one embodiment, the process exhibits integrating behavior that is represented by a non-integrating process model. In another embodiment, an inverse of the model is filtered using a filter that includes a lead time constant that is selected to minimize a steady state error of the predicted process variable. In yet another embodiment, an array of output model values is revised or reindexed in response to a change in a time-varying parameter related to the process.

Claims15

Dependent claims

A control system for controlling a process using a parametric model-based control technique, comprising:

an input through which a set point for the process is input;
an output through which a control output is output to the process for controlling the process;
and
a controller in which a behavior of the process is represented with a model, the model based on at least one time-varying parameter, and the controller configured to:
establish a model output array that contains output values of the model for a series of time samples that includes a time sample corresponding to an estimated dead time of the process;
revise at least a portion of the model output array that corresponds to time samples occurring after the dead time of the process, the revision based on a change in the time-varying parameter;
establish a disturbance array that contains disturbance values for the process for the series of time samples;
revise at least a portion of the disturbance array that corresponds to the revised portion of the model output array so that, for each revised time sample, a predicted process value determined after the change in time-varying parameter is the same as a predicted process value determined before the change;
and
generate a bumpless transfer as the control output for the set point based on the revised model output array and the revised disturbance array in response to the change in time-varying parameter.

7 more elements

A control system for controlling a process using a parametric model-based control technique, comprising:

an input through which a set point for the process is input;
an output through which a control output is output to the process for controlling the process;
and
a controller in which a behavior of the process is represented with a model, the model based on at least one time-varying parameter, and the controller configured to:
establish a model output array that contains output values of the model for a series of time samples that includes a time sample corresponding to an estimated dead time of the process;
revise at least a portion of the model output array that corresponds to time samples occurring after the dead time of the process, the revision based on a change in the time-varying parameter;
and
generate a bumped transfer as the control output for the set point based on the revised model output array and a disturbance of the process in response to the change in time-varying parameter.

5 more elements

Dependencies are inferred from the claim text.