Gain-adaptive process control
AssigneePhillips Petroleum Company
InventorsThomas M. Bartley, Richard F. Giles
Life of this patent
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Abstract
In a process control system, a control signal to the process is provided to a process model having a predictive element and a delay element adapted to reproduce as closely as possible the action of the measured process variable to the control signal. The variable input signal to the process controller, upon which generation of the process control signal is based, is generated by multiplying the signal from the predictive portion of the process model by a correction factor generated in response to the ratio of the actual process measurement signal to the delayed model output signal.
Claims18
A method of controlling a process, said method comprising:
- generating a process control signal in response to a comparison of a controller variable input signal and a controller setpoint signal;
- applying said process control signal to said process to effect control thereof;
- generating, in response to said process control signal, a process prediction signal representative of the predicted response of a measured process variable to said process control signal;
- applying a delay factor, modeled after the response delay of said process, to said process prediction signal to produce a delayed prediction signal;
- generating a process measurement signal representative of the value of said measured process variable;
- generating in response to said process measurement signal and said delayed prediction signal, a correction signal responsive to the ratio of said measured process variable to the delayed process response prediction;
- and
- generating said controller variable input signal in response to the product of said process prediction signal and said correction signal.
Apparatus for controlling a process, said apparatus comprising:
- process controller means for generating a process control signal in response to a comparison of a controller variable input signal and a controller setpoint signal;
- means for providing a process measurement signal representative of the value of a preselected process variable;
- process model means comprising model predictor means for simulating the process gain relationship between said process control signal and said measured process variable signal and delivering a process prediction signal responsive to said process control signal and comprising model delay means for applying a model delay factor to said process prediction signal to produce a delayed prediction signal;
- means for generating, in response to said process measurement signal and said delayed prediction signal, a correction signal responsive to the ratio of said process measurement signal to said delayed prediction signal;
- means for multiplying said process prediction signal by said correction signal to generate said controller variable input signal.
Dependencies are inferred from the claim text.