US3569681A
Expired / Lapsed
US
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Method and system for adaptive control
Assignee: International Business Machines Corp
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Filing: 1967-06-15
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Granted: 1971-03-09
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Expires: 1987-06-15
Abstract
Abstract Adaptive control methods and systems are provided that utilize the relationship between at least one operative criterion of system performance and at least one reference to control the use of one of at least two control laws which establish different operative zones, which are stochastic and deterministic in character. The different control laws used in these two zones provide wide bandwidth under conditions of large signal excursion (deterministic zone), and stability and linearity when the system is at or near the set point (stochastic zone). The error signal may comprise the chosen system performance criterion, and the chosen control laws may differ by using different controller coefficients or by using different samples of system operation. Preferably the switchover point is set with respect to a given multiple of the standard deviation of the noise terms in an equation descriptive of the system, such that the signal excursion is identified with a high degree of probability as being of non-noise origin.
Inventors
- 👤 Richard W Koepcke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:58
CPC Classifications
G; G05; G05B; G05B13/00; G05B13/02; G05B13/0205; G05B13/024; G05B13/0245
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
72 words
The method of operating a control system having a determined noise characteristic comprising the steps of establishing an error signal reference level in accordance with the noise characteristic, monitoring the error signal, comparing the error signal to the reference level, operating the system in accordance with one control law when one relative magnitude relationship exists, and operating the system in accordance with a second control law when a second magnitude relationship exists.
Claim 2
Independent Claim
72 words
The method of operating a control system having a determined noise characteristic comprising the steps of establishing an error signal reference level in accordance with the noise characteristic, monitoring the error signal, comparing the error signal to the reference level, operating the system in accordance with one control law when one relative magnitude relationship exists, and operating the system in accordance with a second control law when a second magnitude relationship exists.
Claim 3
Dependent Claim
55 words
The invention as set forth in claim 1 above, where the error signal reference level is set in correspondence to a value of approximately three times the standard deviation of the noise, and wherein the two control laws are selected to provide an overall response that varies with time substantially linearly with the error signal.
Claim 4
Independent Claim
91 words
A method of adjusting the setting of a process variable in a control system that includes the steps of: comparing excursions of a selected criterion of system performance to a reference, said reference corresponding to approximately three times the standard deviation of noise for the system; adjusting the setting in accordance with a first control law when a first comparative relationship exists; and adjusting the setting in accordance with a second control law when a second comparative relationship exists, the second control law providing a different system response than the first.
Claim 5
Independent Claim
91 words
A method of adjusting the setting of a process variable in a control system that includes the steps of: comparing excursions of a selected criterion of system performance to a reference, said reference corresponding to approximately three times the standard deviation of noise for the system; adjusting the setting in accordance with a first control law when a first comparative relationship exists; and adjusting the setting in accordance with a second control law when a second comparative relationship exists, the second control law providing a different system response than the first.
Claim 6
Dependent Claim
64 words
The invention as set forth in claim 3 above, including in addition the step of repetitively sampling the selected criterion of system performance, and wherein the first control law provides a deterministic zone of operation when the selected criterion is greater than the reference, and the second control law provides a stochastic zone of operation when the selected criterion is less than the reference.
Claim 7
Dependent Claim
139 words
An adaptive control system for adjustment of a process variable in accordance with a predetermined response characteristic and comprising: a control device responsive to an output signal and adjusting the process variable; reference signal generating means defining a selected reference value; set point adjustment means providing desired set point values for said adaptive control system; comparator circuits responsive to the difference between actual and desired set point values for said control device for generating an error signal; relative magnitude comparator circuits receiving said error signal and said reference signal and providing signals indicative of the relative magnitude relationship thereof and representative of different zones of operation; and control circuits coupled to receive said error signal and signals indicative of relative magnitude relationship and providing differently varying selected output signals to said control device dependent upon the relative magnitude relationship.
Claim 8
Dependent Claim
139 words
An adaptive control system for adjustment of a process variable in accordance with a predetermined response characteristic and comprising: a control device responsive to an output signal and adjusting the process variable; reference signal generating means defining a selected reference value; set point adjustment means providing desired set point values for said adaptive control system; comparator circuits responsive to the difference between actual and desired set point values for said control device for generating an error signal; relative magnitude comparator circuits receiving said error signal and said reference signal and providing signals indicative of the relative magnitude relationship thereof and representative of different zones of operation; and control circuits coupled to receive said error signal and signals indicative of relative magnitude relationship and providing differently varying selected output signals to said control device dependent upon the relative magnitude relationship.
Claim 9
Dependent Claim
158 words
An adaptvie control system for adjustment of a process variable in accordance with a predetermined response characteristic, said system having a known noise standard deviation sigma , and comprising: a control device responsive to an output signal and adjusting the process variable; reference signal generating means defining a selected reference value corresponding to approximately 3 sigma ; set point adjustment means providing desired set point values for said adaptive control system; position sensor means responsive to the operation of said control device for providing actual set point values; comparator circuits responsive to the difference between said actual and desired set point values for generating an error signal; relative magnitude comparator circuits receiving said error signal and said reference signal and providing parameter adjustment signals indicative of the relationship thereof and representative of different zones of operation; and contrOl circuits including parameter adjustment elements coupled to receive said parameter adjustment signals and providing output signals to said control device.
Claim 10
Dependent Claim
158 words
An adaptvie control system for adjustment of a process variable in accordance with a predetermined response characteristic, said system having a known noise standard deviation sigma , and comprising: a control device responsive to an output signal and adjusting the process variable; reference signal generating means defining a selected reference value corresponding to approximately 3 sigma ; set point adjustment means providing desired set point values for said adaptive control system; position sensor means responsive to the operation of said control device for providing actual set point values; comparator circuits responsive to the difference between said actual and desired set point values for generating an error signal; relative magnitude comparator circuits receiving said error signal and said reference signal and providing parameter adjustment signals indicative of the relationship thereof and representative of different zones of operation; and contrOl circuits including parameter adjustment elements coupled to receive said parameter adjustment signals and providing output signals to said control device.
Claim 11
Dependent Claim
48 words
The invention as set forth in claim 6 above, wherein said control circuits in accordance with a two-term control function having different control coefficients, and wherein said parameter adjustment signals activate different sets of said control coefficients to provide different control criteria for the different zones of operation.
Claim 12
Dependent Claim
55 words
The invention as set forth in claim 7 above, wherein said zones include a deterministic zone in which the control criterion is such that the error signal is varied substantially linearly with time, and a stochastic zone in which the control criterion is such as to tend to minimize the sum of the errors squared.
Claim 13
Independent Claim
142 words
A method of adjusting the setting of a process variable that includes the steps of: measuring said variable; generating an error signal which represents the difference between the measured value of said variable and the desired value of said variable; controlling said variable in response to said error signal and in accordance with a control law which has certain parameters; comparing the magnitude of the error signal to a predetermined magnitude; adjusting said parameters in accordance with a first adaptive law when said error signal is smaller than said predetermined magnitude, said first adaptive law taking into account a relatively large number of past values; and adjusting said parameters in accordance with a second adaptive control law when said error signal is greater than said prespecified magnitude, said second adaptive control law taking into account a relatively small number of past values.
Claim 14
Independent Claim
142 words
A method of adjusting the setting of a process variable that includes the steps of: measuring said variable; generating an error signal which represents the difference between the measured value of said variable and the desired value of said variable; controlling said variable in response to said error signal and in accordance with a control law which has certain parameters; comparing the magnitude of the error signal to a predetermined magnitude; adjusting said parameters in accordance with a first adaptive law when said error signal is smaller than said predetermined magnitude, said first adaptive law taking into account a relatively large number of past values; and adjusting said parameters in accordance with a second adaptive control law when said error signal is greater than said prespecified magnitude, said second adaptive control law taking into account a relatively small number of past values.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |