US3876872A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process control system and method with integral-action set-point optimization using statistically-variable gain control responsive to fraction defective
Assignee: Industrial Nucleonics Corp
•
Filing: 1971-10-14
•
Granted: 1975-04-08
•
Expires: 1991-10-14
Abstract
Abstract A continuous material production process is regulated by a controller whose set point is automatically optimized according to statistical computations based on inputs of measured fraction defective and fraction defective set-point values. These values are each converted to a linear deviation quantity based on an estimate of standard deviation computed from defect level, process average and measured fraction defective. The deviation quantities and the difference therebetween are computed repeatedly, and the difference values are accumulated to provide integral control of the set point for the process controller.
Inventors
- 👤 David Allan Spitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:51
CPC Classifications
G; G05; G05D; G05D5/00; G05D5/02; G05D5/03; G05B; G05B13/00; G05B13/02
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
83 words
In a process control system wherein process measurements are compared with a defect limit and with a process controller setpoint which is automatically reset in accordance with a fraction defective signal derived from the defect limit comparison, the improvement comprising means responsive to the measurements for producing a setpoint error signal dependent upon the deviation of the process average from the defect limit and the fraction defective signal, and reset means utilizing said error signal to vary the setpoint for the process controller.
Claim 2
Dependent Claim
83 words
In a process control system wherein process measurements are compared with a defect limit and with a process controller setpoint which is automatically reset in accordance with a fraction defective signal derived from the defect limit comparison, the improvement comprising means responsive to the measurements for producing a setpoint error signal dependent upon the deviation of the process average from the defect limit and the fraction defective signal, and reset means utilizing said error signal to vary the setpoint for the process controller.
Claim 3
Dependent Claim
90 words
Apparatus as in claim 1 wherein said set point error signal producing means comprises means providing a signal indicative of a fraction defective set point, means for generating a pair of deviation signals, one indicative of the deviation of said defect limit from the average and the other indicative of the deviation from the average of a second defect limit which would produce the fraction defective value indicated by said fraction defective set point, said set point error signal being indicative of the difference between said pair of deviation signals.
Claim 4
Dependent Claim
40 words
Apparatus as in claim 1 wherein values of said set-point error signal are computed repeatedly, and wherein said reset means comprises means for accumulating said set-point error signal values, thereby to provide integral control of said process controller set point.
Claim 5
Dependent Claim
40 words
Apparatus as in claim 2 wherein values of said set-point error signal are computed repeatedly, and wherein said reset means comprises means for accumulating said set-point error signal values, thereby to provide integral control of said process controller set point.
Claim 6
Dependent Claim
141 words
In a process control system wherein process measurements are compared with a defect limit and with a process controller setpoint which is automatically reset in accordance with a fraction defective signal derived from the defect limit comparison, the improvement comprising: means for converting said fraction defective signal to a first deviation signal which is dependent upon a function of the standard deviation of the process and of the deviation of the process average from the defect limit, means for generating a second deviation signal which is dependent upon a function of the standard deviation of the process and of a reference deviation of the process average from the defect limit, means responsive to a difference between said first and second deviation signals for producing a setpoint error signal and means responsive to said error signal for resetting said process controller setpoint.
Claim 7
Dependent Claim
141 words
In a process control system wherein process measurements are compared with a defect limit and with a process controller setpoint which is automatically reset in accordance with a fraction defective signal derived from the defect limit comparison, the improvement comprising: means for converting said fraction defective signal to a first deviation signal which is dependent upon a function of the standard deviation of the process and of the deviation of the process average from the defect limit, means for generating a second deviation signal which is dependent upon a function of the standard deviation of the process and of a reference deviation of the process average from the defect limit, means responsive to a difference between said first and second deviation signals for producing a setpoint error signal and means responsive to said error signal for resetting said process controller setpoint.
Claim 8
Dependent Claim
38 words
Apparatus as in claim 5 which comprises means for deriving said set-point error signal repeatedly, means for accumulating the repeatedly derived values, and means for resetting said process controller set point in response to said accumulated signal values.
Claim 9
Dependent Claim
55 words
Apparatus as in claim 5 wherein said second deviation signal generating means comprises means for generating a fraction defective set-point signal, means for generating a signal indicative of the standard deviation of the process and means for mathematically combining said fraction defective set-point signal and said standard deviation signal to produce said second deviation signal.
Claim 10
Dependent Claim
37 words
Apparatus as in claim 7 for maximizing the economic profit from the operation of the process which comprises means for computing a value for said fraction defective setpoint signal substantially in accordance with the relations expressed by
Claim 11
Dependent Claim
94 words
In a process control apparatus wherein process measurements are compared with a defect limit and with a process controller set point which is automatically reset in accordance with a fraction defective signal derived from the defect limit comparison, the improvement comprising means for converting said fraction defective signal to a linear deviation signal which is dependent upon a function of the standard deviation of the process and of the deviation of the process average from the defect limit, and means for resetting said process controller set point in response to said linear deviation signal.
Claim 12
Dependent Claim
94 words
In a process control apparatus wherein process measurements are compared with a defect limit and with a process controller set point which is automatically reset in accordance with a fraction defective signal derived from the defect limit comparison, the improvement comprising means for converting said fraction defective signal to a linear deviation signal which is dependent upon a function of the standard deviation of the process and of the deviation of the process average from the defect limit, and means for resetting said process controller set point in response to said linear deviation signal.
Claim 13
Dependent Claim
36 words
Apparatus as in claim 9 comprising means for deriving said linear deviation signal repeatedly, means for accumulating the repeatedly derived values and means for resetting said process controller set point in response to said accumulated signal.
Claim 14
Dependent Claim
133 words
Apparatus for determining the standard deviation of a property of a manufactured product, which comprises means for measuring said product to produce a measurement signal indicative of the value of said property, means for producing a defect limit signal indicative of a defect limit for said property, means for comparing said measurement signal with said defect limit signal over a period of time to produce a fraction defective signal indicative of the amount of said product wherein said property has a value on one side of said defect limit, means for averaging said measurement signal for a period of time to produce an average signal means for mathematically combining said defect limit signal, said fraction defective signal and said average signal to produce a signal indicative of the standard deviation of said property.
Claim 15
Dependent Claim
133 words
Apparatus for determining the standard deviation of a property of a manufactured product, which comprises means for measuring said product to produce a measurement signal indicative of the value of said property, means for producing a defect limit signal indicative of a defect limit for said property, means for comparing said measurement signal with said defect limit signal over a period of time to produce a fraction defective signal indicative of the amount of said product wherein said property has a value on one side of said defect limit, means for averaging said measurement signal for a period of time to produce an average signal means for mathematically combining said defect limit signal, said fraction defective signal and said average signal to produce a signal indicative of the standard deviation of said property.
Claim 16
Dependent Claim
112 words
In the method of statistically evaluating a product by gauging a property of the product with an instrument subject to inherent statistical variations to produce a measurement signal exhibiting both product variations and instrument variations and deriving from said signal a computed statistical response related to the degree of uniformity of said product, the improvement which comprises generating an input quantity statistically related to the degree of uniformity of said measurement signal when the product exhibits a constant value of said property, and mathematically combining said measurement signal with said statistically related input quantity so as to render said computed statistical response substantially independent of said inherent statistical variations of said instrument.
Claim 17
Dependent Claim
112 words
In the method of statistically evaluating a product by gauging a property of the product with an instrument subject to inherent statistical variations to produce a measurement signal exhibiting both product variations and instrument variations and deriving from said signal a computed statistical response related to the degree of uniformity of said product, the improvement which comprises generating an input quantity statistically related to the degree of uniformity of said measurement signal when the product exhibits a constant value of said property, and mathematically combining said measurement signal with said statistically related input quantity so as to render said computed statistical response substantially independent of said inherent statistical variations of said instrument.
Claim 18
Dependent Claim
65 words
The method of claim 12 wherein said input quantity generating step comprises measuring a typical sample portion of a product having a substantially constant value of said property, said measuring step being performed with an instrument subject to the inherent statistical variations, computing a standard deviation value for the resulting variations in said measurement signal, and producing an input signal proportional to said standard deviation.
Claim 19
Dependent Claim
69 words
The method of claim 12 wherein said property indicated by said measurement signal is to be compared with a product defect limit indicative of an allowable deviation from the main value of the property, and wherein said mathematical combining step comprises increasing said allowable deviation as a function of said input quantity to provide a process defect limit signal for comparison with said measurement signal when said property varies.
Claim 20
Dependent Claim
73 words
The method of claim 14 which comprises in a computer computing from the measurements the average value of the property to produce an average signal and from a comparison of the measurements and the process defect limit the fraction defective to produce a fraction defective signal and combining the average signal, the fraction defective signal and said process defect limit signal to produce a signal indicative of the standard deviation of the property.
Claim 21
Independent Claim
219 words
A method of controlling the average value of a property of a material product processor output comprising measuring a property of the output, responding to the measured property to derive a setpoint for an actuator controlling the property average value, controlling the actuator of the processor in response to the setpoint so that the average value of the property is controlled to the setpoint, said setpoint being derived by: comparing the measured property with a defect limit to derive a fraction defective signal, converting said fraction defective signal to a first deviation signal which is dependent upon a function of the standard deviation of the process and of the deviation of the process average from the defect limit, in response to the measured property generating a second deviation signal which is dependent upon a function of the standard deviation of the process and of a reference deviation of the process average from the defect limit, producing a setpoint error signal in response to a difference between said first and second deviation signals and resetting said setpoint in response to said error signal, whereby control of the setpoint is automatically linearized as to its gain requirements and the average value is thus varied at a relatively rapid rate in response to changes in the statistical characteristics of the measured property.
Claim 22
Independent Claim
219 words
A method of controlling the average value of a property of a material product processor output comprising measuring a property of the output, responding to the measured property to derive a setpoint for an actuator controlling the property average value, controlling the actuator of the processor in response to the setpoint so that the average value of the property is controlled to the setpoint, said setpoint being derived by: comparing the measured property with a defect limit to derive a fraction defective signal, converting said fraction defective signal to a first deviation signal which is dependent upon a function of the standard deviation of the process and of the deviation of the process average from the defect limit, in response to the measured property generating a second deviation signal which is dependent upon a function of the standard deviation of the process and of a reference deviation of the process average from the defect limit, producing a setpoint error signal in response to a difference between said first and second deviation signals and resetting said setpoint in response to said error signal, whereby control of the setpoint is automatically linearized as to its gain requirements and the average value is thus varied at a relatively rapid rate in response to changes in the statistical characteristics of the measured property.
Claim 23
Dependent Claim
32 words
The method of claim 16 which comprises deriving said set-point error signal repeatedly, accumulating the repeatedly derived values, and resetting said process controller set point in response to said accumulated signal values.
Claim 24
Dependent Claim
48 words
The method of claim 16 wherein said second deviation signal generating step comprises generating a fraction defective set-point signal, generating a signal indicative of the standard deviation of the process mathmatically combining said fraction defective set-point signal and said standard deviation signal to produce said second deviation signal.
Claim 25
Dependent Claim
35 words
The method of claim 18 for maximizing the economic profit from the operation of the process which comprises computing a value for said fraction defective set-point signal substantially in accordance with the relations expressed by
Claim 26
Independent Claim
166 words
A method of controlling the average value of a property of a material product processor output comprising measuring a property of the output, responding to the measured property to derive a setpoint for an actuator controlling the property average value, controlling the actuator of the processor in response to the setpoint so that the average value of the property is controlled to the setpoint, said setpoint being derived by: comparing the measured property with a defect limit to derive a fraction defective signal, converting said fraction defective signal to a linear deviation signal which is dependent upon a function of the standard deviation of the process and of the deviation of the process average from the defect limit, and resetting said setpoint in response to said linear deviation signal, whereby control of the setpoint is automatically linearized as to its gain requirements and the average value is thus varied at a relatively rapid rate in response to changes in the statistical characteristics of the measured property.
Claim 27
Independent Claim
166 words
A method of controlling the average value of a property of a material product processor output comprising measuring a property of the output, responding to the measured property to derive a setpoint for an actuator controlling the property average value, controlling the actuator of the processor in response to the setpoint so that the average value of the property is controlled to the setpoint, said setpoint being derived by: comparing the measured property with a defect limit to derive a fraction defective signal, converting said fraction defective signal to a linear deviation signal which is dependent upon a function of the standard deviation of the process and of the deviation of the process average from the defect limit, and resetting said setpoint in response to said linear deviation signal, whereby control of the setpoint is automatically linearized as to its gain requirements and the average value is thus varied at a relatively rapid rate in response to changes in the statistical characteristics of the measured property.
Claim 28
Dependent Claim
35 words
The method of claim 20 wherein said linear deviation signal is derived repeatedly, wherein the repeatedly derived values are accumulated and wherein said process controller set point resetting is in response to said accumulated signal.
Claim 29
Independent Claim
198 words
A method of controlling the average value of a property of a material product processor output comprising measuring a property of the output, responding to the measured property to derive a setpoint for an actuator controlling the property average value, controlling the actuator of the processor in response to the setpoint so that the average value of the property is controlled to the setpoint, said setpoint being derived by: comparing the measured property with a defect limit to derive a fraction defective signal, comparing the fraction defective signal with a fraction defective setpoint signal and controlling the actuator setpoint in response to the comparison so that the compared fractions are substantially equalized, producing a representation of the material savings resulting from a predetermined change in the average property value, producing a representation of the loss resulting from a predetermined change in the fraction defective, responding to the measured property values to produce a statistical response related to the degree of uniformity of said product, and in a computer, mathematically combining said savings and loss representations with said statistical response to produce said fraction defective setpoint signal, thereby to maximize the economic profit from the operation of said processor.
Claim 30
Independent Claim
198 words
A method of controlling the average value of a property of a material product processor output comprising measuring a property of the output, responding to the measured property to derive a setpoint for an actuator controlling the property average value, controlling the actuator of the processor in response to the setpoint so that the average value of the property is controlled to the setpoint, said setpoint being derived by: comparing the measured property with a defect limit to derive a fraction defective signal, comparing the fraction defective signal with a fraction defective setpoint signal and controlling the actuator setpoint in response to the comparison so that the compared fractions are substantially equalized, producing a representation of the material savings resulting from a predetermined change in the average property value, producing a representation of the loss resulting from a predetermined change in the fraction defective, responding to the measured property values to produce a statistical response related to the degree of uniformity of said product, and in a computer, mathematically combining said savings and loss representations with said statistical response to produce said fraction defective setpoint signal, thereby to maximize the economic profit from the operation of said processor.
Claim 31
Dependent Claim
21 words
The method of claim 22 wherein said fraction defective set-point signal is determined substantially in accordance with the relations expressed by
Claim 32
Independent Claim
199 words
A method of controlling a processor output comprising measuring a property of the output, responding to the measured property to derive a control signal for an actuator controlling the property, controlling the actuator in response to the control signal, said signal being derived by computing in a computer: the standard deviation of the measured property; said standard deviation being computed by: supplying to the computer a defect limit signal indicative of a defect limit for said property and comparing the value of the measured property with said defect limit signal over a period of time to produce a fraction defective signal indicative of the amount of said product wherein said property has a value on one side of said defect limit, averaging said measurement signal for a period of time to produce an average signal and mathematically combining said defect limit signal, said fraction defective signal and said average signal to produce a signal indicative of the standard deviation of said property, whereby control of the setpoint is automatically linearized as to its gain requirements and the average value is thus varied at a relatively rapid rate in response to changes in the statistical characteristics of the measured property.
Claim 33
Independent Claim
199 words
A method of controlling a processor output comprising measuring a property of the output, responding to the measured property to derive a control signal for an actuator controlling the property, controlling the actuator in response to the control signal, said signal being derived by computing in a computer: the standard deviation of the measured property; said standard deviation being computed by: supplying to the computer a defect limit signal indicative of a defect limit for said property and comparing the value of the measured property with said defect limit signal over a period of time to produce a fraction defective signal indicative of the amount of said product wherein said property has a value on one side of said defect limit, averaging said measurement signal for a period of time to produce an average signal and mathematically combining said defect limit signal, said fraction defective signal and said average signal to produce a signal indicative of the standard deviation of said property, whereby control of the setpoint is automatically linearized as to its gain requirements and the average value is thus varied at a relatively rapid rate in response to changes in the statistical characteristics of the measured property.
References Cited (Backward Citations)
US3151237A
Cited
US3260838A
Cited
US3408486A
Cited
US3515860A
Cited
US3622448A
Cited
US3648035A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |