Process control having improved combination of feedforward feedback control
First Claim
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1. A process controller comprising:
- (a) a feedback circuit including;
first means for outputting a first signal corresponding to a difference between a control target variable and a process result,second means for outputting a second signal, which is obtained by converting the first signal based on a predetermined transfer function, andthird means, controlled on the basis of the second signal, for outputting a control result; and
(b) a feedforward circuit including;
fourth means, responsive to an external signal and coupled to said second means, for detecting a static characteristic compensation signal representing a product of the second signal and a quotient obtained by dividing a difference between present and previous external signals with the previous external signal, andfifth means, coupled to said fourth means, said first means, and said second means, for supplying a composite signal of the first signal and the static characteristic compensation signal to said second means.
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Abstract
A process controller includes a change fetch circuit for fetching a change in feedforward controlled variable due to a variation in load, and an auto-tuning control circuit for performing auto-tuning for mis-matching of the feedforward control, in accordance with a compensation variable obtained by multiplying a ratio of an adjusted output signal of a feedback control system corrected by the feedforward control to the feedforward controlled variable, with the change in feedforward controlled variable, to determine an optimal next feedforward controlled variable.
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15 Claims
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1. A process controller comprising:
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(a) a feedback circuit including; first means for outputting a first signal corresponding to a difference between a control target variable and a process result, second means for outputting a second signal, which is obtained by converting the first signal based on a predetermined transfer function, and third means, controlled on the basis of the second signal, for outputting a control result; and (b) a feedforward circuit including; fourth means, responsive to an external signal and coupled to said second means, for detecting a static characteristic compensation signal representing a product of the second signal and a quotient obtained by dividing a difference between present and previous external signals with the previous external signal, and fifth means, coupled to said fourth means, said first means, and said second means, for supplying a composite signal of the first signal and the static characteristic compensation signal to said second means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A process controller for performing feedforward control in accordance with a variation in load for a feedback control system, comprising:
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change fetch means for fetching a change in a feedforward controlled variable, in accordance with a variation in load; and control means, coupled to said change fetch means, for performing feedforward control in accordance with a compensation signal obtained by multiplying the change in the feedforward controlled variable with a ratio of an adjusted output signal of the feedback control system, corrected by feedforward control to the feedforward controlled variable.
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Specification