US5164647A
Expired / Lapsed
US
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Multivariable adaptive vibration canceller
Assignee: Northrop Grumman Corp
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Filing: 1990-12-24
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Granted: 1992-11-17
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Expires: 2010-12-24
Abstract
Abstract A system for minimizing periodically induced vibration in a mechanical structure, particularly rotary shaft apparatus that is not limited to the use of any particular number or type of forcers or sensors and requires no knowledge of the mechanical structure's transfer function. In accordance with a preferred embodiment the system senses periodically induced vibration utilizing a plurality of sensors and produces a complex output representative of the algebraic sum of the vibrations sensed for each harmonic and counteracting the vibration with a plurality of actuators operatively coupled to the structure by producing a counteracting vibration therein in response to a complex input signal for each actuator in the form of a matrix of system responses to vibrational inputs at selected harmonics of interest. More specifically, the complex inputs for the actuators are produced on the basis of an adaptation cycle wherein the effect of an adjustment of the complex inputs on the complex outputs is utilized to determine the nature of a successive adjustment of the complex inputs utilizing a control algorithm.
Inventors
- 👤 Clinton W. Moulds, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:30
CPC Classifications
G; G05; G05D; G05D19/00; G05D19/02
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
182 words
A multivariable adaptive vibration canceller for cancelling periodically induced vibration in a mechanical structure comprising: a plurality of actuators operatively coupled to the structure for producing a counteracting vibration therein in response to a complex input signal for each actuator, the structure having a dynamic structural system characteristic in the form of a matrix of system responses to vibrational inputs at selected harmonics of interest; a plurality of sensors, at least equal to the number of actuators coupled to the structure for sensing periodically induced vibration and actuator induced vibration, said sensors producing a complex output representative of the algebraic sum of the vibrations sensed thereby for each harmonic; multivariable adaptive vibration cancellation processor means responsive to complex outputs of the sensors for producing the complex inputs to the actuators, said vibration cancellation processor means producing said inputs on the basis of an adaptation cycle wherein the effect of an adjustment of said complex inputs on said complex outputs is utilized to determine the nature of a successive adjustment of the complex inputs independent of knowledge of said dynamic structural system characteristic.
Claim 2
Dependent Claim
182 words
A multivariable adaptive vibration canceller for cancelling periodically induced vibration in a mechanical structure comprising: a plurality of actuators operatively coupled to the structure for producing a counteracting vibration therein in response to a complex input signal for each actuator, the structure having a dynamic structural system characteristic in the form of a matrix of system responses to vibrational inputs at selected harmonics of interest; a plurality of sensors, at least equal to the number of actuators coupled to the structure for sensing periodically induced vibration and actuator induced vibration, said sensors producing a complex output representative of the algebraic sum of the vibrations sensed thereby for each harmonic; multivariable adaptive vibration cancellation processor means responsive to complex outputs of the sensors for producing the complex inputs to the actuators, said vibration cancellation processor means producing said inputs on the basis of an adaptation cycle wherein the effect of an adjustment of said complex inputs on said complex outputs is utilized to determine the nature of a successive adjustment of the complex inputs independent of knowledge of said dynamic structural system characteristic.
Claim 3
Dependent Claim
128 words
A multivariable adaptive vibration canceller according to claim 1, wherein said cancellation processor means includes means for performing a control algorithm to determine the complex input, said control algorithm being: x.sub.j+1 =x.sub.j +β[E.sup.2 (x.sub.j)-E.sup.2 (x.sub.j +u.sub.j)]u.sub.j where x j is a nominal value of the complex input during a current adaptation cycle j, x j+1 is the nominal value of the complex input vector for the next adaptation cycle j+1, E 2 ( ) is the square of the complex output measured with a perturbed (x j +u j ) and an unperturbed (x j ) complex input, u j is the jth sample of a random vector with covariance σ 2 I, and β is a positive constant used to control the speed of adjustment of x.
Claim 4
Dependent Claim
77 words
A multivariable adaptive vibration canceller according to claim 1, wherein the vibration canceller processor means changes the value of x j+1 in the direction of u j when a decrease in E 2 occurs in response to adding of u j to the complex input x j , and changes x j+1 in a direction opposite to u j when E 2 increases in response to adding of u j to the complex input x j .
Claim 5
Dependent Claim
16 words
A multivariable adaptive vibration canceller according to claim 3, wherein said structure includes a rotating shaft.
Claim 6
Dependent Claim
16 words
A multivariable adaptive vibration canceller according to claim 2, wherein said structure includes a rotating shaft.
Claim 7
Dependent Claim
16 words
A multivariable adaptive vibration canceller according to claim 1, wherein said structure includes a rotating shaft.
Claim 8
Dependent Claim
14 words
A multivariable adaptive vibration canceller according to claim 1, wherein said sensors comprise accelerometers.
Claim 9
Dependent Claim
14 words
A multivariable adaptive vibration canceller according to claim 2, wherein said sensors comprise accelerometers.
Claim 10
Dependent Claim
14 words
A multivariable adaptive vibration canceller according to claim 3, wherein said sensors comprise accelerometers.
Claim 11
Dependent Claim
14 words
A multivariable adaptive vibration canceller according to claim 4, wherein said sensors comprise accelerometers.
Claim 12
Dependent Claim
14 words
A multivariable adaptive vibration canceller according to claim 6, wherein said sensors comprise accelerometers.
Claim 13
Independent Claim
163 words
A method for adaptively cancelling periodically induced vibration in a mechanical structure comprising the steps of: sensing periodically induced vibration utilizing a plurality of sensors and producing a complex output representative of the algebraic sum of the vibrations sensed thereby for each harmonic; counteracting said vibration with a plurality of actuators operatively coupled to the structure by producing a counteracting vibration therein in response to a complex input signal for each actuator in the form of a matrix of system responses to vibrational inputs at selected harmonics of interest; producing the complex inputs for the actuators on the basis of an adaptation cycle wherein the effect of an adjustment of said complex inputs on said complex outputs is utilized to determine the nature of a successive adjustment of the complex inputs independent of knowledge of a dynamic structural system characteristic of the mechanical structure in the form of a matrix of system responses to known vibrational inputs at the selected harmonics of interest.
Claim 14
Independent Claim
163 words
A method for adaptively cancelling periodically induced vibration in a mechanical structure comprising the steps of: sensing periodically induced vibration utilizing a plurality of sensors and producing a complex output representative of the algebraic sum of the vibrations sensed thereby for each harmonic; counteracting said vibration with a plurality of actuators operatively coupled to the structure by producing a counteracting vibration therein in response to a complex input signal for each actuator in the form of a matrix of system responses to vibrational inputs at selected harmonics of interest; producing the complex inputs for the actuators on the basis of an adaptation cycle wherein the effect of an adjustment of said complex inputs on said complex outputs is utilized to determine the nature of a successive adjustment of the complex inputs independent of knowledge of a dynamic structural system characteristic of the mechanical structure in the form of a matrix of system responses to known vibrational inputs at the selected harmonics of interest.
Claim 15
Dependent Claim
137 words
A method for cancelling vibration according to claim 12, wherein said step of producing the complex inputs on the basis of an adaptation cycle is performed utilizing a control algorithm to determine the complex input, said control algorithm being: x.sub.j+1 =x.sub.j +β[E.sup.2 (x.sub.j)-E.sup.2 (x.sub.j +u.sub.j)]u.sub.j where x j is a nominal value of the complex input during a current adaptation cycle j, x j+1 is the nominal value of the complex input vector for the next adaptation cycle j+1, E 2 ( ) is the square of the complex output measured with a perturbed (x j +u j ) and an unperturbed (x j ) complex input, u j is the jth sample of a random vector with covariance σ 2 I, and β is a positive constant used to control the speed of adjustment of x.
Claim 16
Dependent Claim
77 words
A method for cancelling vibration according to claim 13, wherein the value of x j+1 is changed in the direction of u j when a decrease in E 2 occurs in response to adding of u j to the complex input x j , and the value of x j+1 is changed in a direction opposite to u j when E 2 increases in response to adding of u j to the complex input x j .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-11-17 | 1996-05-18 | 1996-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-17 | 2000-05-18 | 2000-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-17 | 2004-05-18 | 2004-11-17 | $7700.00 | Window Closed / Lapsed |