US5412951A
Expired / Lapsed
US
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Cyrogenic cooling system with active vibration control
Assignee: Raytheon Co
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Filing: 1993-12-22
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Granted: 1995-05-09
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Expires: 2013-12-22
Abstract
Abstract A cryogenic cooling system having a mechanism for canceling vibration at a fundamental frequency and at harmonics thereof. The inventive system includes a first apparatus (28, 32) for cooling a mass. The first apparatus (28, 32) creates a vibration at a first frequency and a second frequency. In a typical application, the first frequency is a fundamental frequency and the second frequency is a harmonic of the first frequency. Often several harmonics are present. The invention includes a second apparatus (30, 34) for substantially eliminating vibration at the first frequency and a third apparatus (48, 50) for substantially eliminating vibration at the second frequency. The second apparatus includes a mass (30) and a motor (34) for driving same. The mass (30) is disposed to counter the vibration created by the first apparatus when the motor (34) is driven by a first current. The third apparatus includes a sensor (48) for detecting the vibration at the second frequency and providing an output in response to a sensed force F resulting therefrom. The third apparatus further includes a feedback circuit (50) for providing a second current for driving the motor. The second current is the sum of the first current and a feedback current I b2 . The feedback current I b2 is equal to -G f (s)F, where -G f (s) is a feedback transfer function. The feedback transfer function is a product of a first transfer function H I (s) representing dynamics of the second apparatus required to cancel the vibration at the first frequency and a second transfer function G D (s) representing the dynamics of the second means required to cancel the harmonic vibration.
Inventors
- 👤 Yeong-Wei A. Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:17
CPC Classifications
F; F25; F25B; F25B31/00; F16; F16F; F16F15/00; F16F15/002; F25B9/00; F25B9/14; G; G05; G05D; G05D19/00; G05D19/02; F25B2309/00; F25B2309/001; F25B2500/00; F25B2500/13
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
208 words
A cryogenic cooling system with active vibration control comprising: first means for cooling a mass, said first means creating a first vibration at a first frequency and a second frequency; second means for substantially eliminating said vibration at said first frequency, said second means including a mass and motor means for driving same, said mass being disposed to counter said first vibration, and said motor means being driven by a first current; and third means for substantially eliminating said vibration at said second frequency, said third means including: means for sensing said vibration at said second frequency and providing an output in response to a sensed force F resulting therefrom and feedback means for providing a second current for driving said motor means, said second current being the sum of said first current and a feedback current I b2 , said feedback current I b2 being equal to -G f (s)F where -G f (s) is a feedback transfer function which is a product of a first transfer function H I (s) representing dynamics of said second means required to cancel said vibration at said first frequency and a second transfer function G D (s) representing the dynamics of said second means required to cancel said harmonic vibration.
Claim 2
Dependent Claim
208 words
A cryogenic cooling system with active vibration control comprising: first means for cooling a mass, said first means creating a first vibration at a first frequency and a second frequency; second means for substantially eliminating said vibration at said first frequency, said second means including a mass and motor means for driving same, said mass being disposed to counter said first vibration, and said motor means being driven by a first current; and third means for substantially eliminating said vibration at said second frequency, said third means including: means for sensing said vibration at said second frequency and providing an output in response to a sensed force F resulting therefrom and feedback means for providing a second current for driving said motor means, said second current being the sum of said first current and a feedback current I b2 , said feedback current I b2 being equal to -G f (s)F where -G f (s) is a feedback transfer function which is a product of a first transfer function H I (s) representing dynamics of said second means required to cancel said vibration at said first frequency and a second transfer function G D (s) representing the dynamics of said second means required to cancel said harmonic vibration.
Claim 3
Dependent Claim
27 words
The invention of claim 1 wherein said first transfer function H I (s) is equal to (1+G b (s)P b (s))M b s 2 P b (s).
Claim 4
Dependent Claim
53 words
The invention of claim 2 wherein said second transfer function G D (s) is equal to the summation over the index "i" as "i" goes from 1 to a number "n" representing a number of harmonics of a plurality of terms given by the expression K Di s/(s 2 +ω Di 2 ).
Claim 5
Dependent Claim
13 words
The invention of claim 1 wherein said first means includes a first piston.
Claim 6
Dependent Claim
16 words
The invention of claim 4 wherein said first means includes means for activating said first piston.
Claim 7
Dependent Claim
15 words
The invention of claim 5 wherein said first piston is activated at said first frequency.
Claim 8
Dependent Claim
13 words
The invention of claim 6 wherein said second means includes a second piston.
Claim 9
Dependent Claim
16 words
The invention of claim 7 wherein said second means includes means for activating said second piston.
Claim 10
Dependent Claim
37 words
The invention of claim 8 wherein said means for sensing said vibration at said second frequency and providing a sensed current in response thereto includes a transducer for sensing vibration at said first and said second frequencies.
Claim 11
Dependent Claim
27 words
The invention of claim 9 wherein said first transfer function H I (s) is equal to (1+G b (s)P b (s))/M b s 2 P b (s).
Claim 12
Dependent Claim
53 words
The invention of claim 10 wherein said second transfer function G D (s) is equal to the summation over the index "i" as "i" goes from 1 to a number "n" representing a number of harmonics of a plurality of terms given by the expression K Di s/(s 2 +ω Di 2 ).
Claim 13
Dependent Claim
13 words
The invention of claim 11 wherein said motor means includes a linear motor.
Claim 14
Dependent Claim
13 words
The invention of claim 12 wherein said linear motor is a solenoid coil.
Claim 15
Dependent Claim
24 words
The invention of claim 1 wherein said first frequency is said fundamental frequency and said second frequency is a harmonic of said first frequency.
Claim 16
Dependent Claim
14 words
The invention of claim 1 wherein said cooling system is a Sterling cycle cooler.
Claim 17
Dependent Claim
14 words
The invention of claim 15 wherein said cooling system is a Split-Sterling cycle cooler.
Claim 18
Independent Claim
197 words
A method for eliminating vibration at a harmonic of a fundamental frequency of vibration of a cryogenic cooling system, said method including the steps of: cooling a mass and creating a vibration at a first frequency and a second frequency; substantially eliminating said vibration at said first frequency by driving a mass disposed to create a vibration opposing said vibration with a motor in response to a first current; and substantially eliminating said vibration at said second frequency, including the steps of: sensing said vibration at said second frequency and providing an output in response to a sensed force F resulting therefrom and providing a second current for driving said motor means, said second current being the sum of said first current and a feedback current I b2 , said feedback current I b2 being equal to -G f (s)F where -G f (s) is a feedback transfer function which is a product of a first transfer function H I (s) representing dynamics of said second means required to cancel said vibration at said first frequency and a second transfer function G D (s) representing the dynamics of said second means required to cancel said harmonic vibration.
Claim 19
Independent Claim
197 words
A method for eliminating vibration at a harmonic of a fundamental frequency of vibration of a cryogenic cooling system, said method including the steps of: cooling a mass and creating a vibration at a first frequency and a second frequency; substantially eliminating said vibration at said first frequency by driving a mass disposed to create a vibration opposing said vibration with a motor in response to a first current; and substantially eliminating said vibration at said second frequency, including the steps of: sensing said vibration at said second frequency and providing an output in response to a sensed force F resulting therefrom and providing a second current for driving said motor means, said second current being the sum of said first current and a feedback current I b2 , said feedback current I b2 being equal to -G f (s)F where -G f (s) is a feedback transfer function which is a product of a first transfer function H I (s) representing dynamics of said second means required to cancel said vibration at said first frequency and a second transfer function G D (s) representing the dynamics of said second means required to cancel said harmonic vibration.
References Cited (Backward Citations)
US4567726A
Cited
US5245830A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-05-08 | 1998-11-07 | 1999-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-05-08 | 2002-11-07 | 2003-05-09 | $3760.00 | Window Closed / Lapsed |
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