US4372162A
Expired / Lapsed
US
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Three-axis accelerometer having dynamic bias compensation
Assignee: Boeing North American Inc
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Filing: 1981-08-13
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Granted: 1983-02-08
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Expires: 2001-08-13
Abstract
Abstract A proof mass for an accelerometer is electromagnetically constrained in three orthogonal directions. An array of filaments forms an elastic suspension for the proof mass to constrain it in the remaining degrees of freedom. The resulting instrument has the potential for low cost and high-accuracy operation over a wide temperature range without the use of temperature controls. Means are provided in the accelerometer for dynamically nulling the bias.
Inventors
- 👤 Sidney G. Shutt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:00
CPC Classifications
G; G01; G01P; G01P15/00; G01P15/02; G01P15/08; G01P15/13; G01P15/132; G01P15/125; G01P15/18
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
109 words
An accelerometer, comprising: a base; a proof mass; primary control means for maintaining the position of said proof mass relative to said base, wherein said primary control means produces an output signal proportional to acceleration of said proof mass and base; elastic suspension means for means for maintaining the position of said proof mass relative to said base; means for producing a periodic variation of stress in said elastic suspension means and a corresponding periodic variation proportional to bias in said output signal; and means for sensing said periodic variation proportional to bias and for using said periodic variation proportional to bias to provide dynamic bias compensation or calibration.
Claim 2
Dependent Claim
109 words
An accelerometer, comprising: a base; a proof mass; primary control means for maintaining the position of said proof mass relative to said base, wherein said primary control means produces an output signal proportional to acceleration of said proof mass and base; elastic suspension means for means for maintaining the position of said proof mass relative to said base; means for producing a periodic variation of stress in said elastic suspension means and a corresponding periodic variation proportional to bias in said output signal; and means for sensing said periodic variation proportional to bias and for using said periodic variation proportional to bias to provide dynamic bias compensation or calibration.
Claim 3
Dependent Claim
34 words
The accelerometer recited in claim 1, wherein said means for sensing said periodic variation proportional to bias is included in secondary closed-loop control means for maintaining said proof mass at its mechanical null position.
Claim 4
Dependent Claim
53 words
The accelerometer recited in claim 1, wherein said elastic suspension means comprises a plurality of filaments held in tension between said proof mass and said base; and wherein said means for producing a periodic variation of tension in said elastic suspension means operates to produce a periodic variation of tension in said filaments.
Claim 5
Dependent Claim
26 words
The accelerometer recited in claim 3, wherein said plurality of filaments are disposed substantially in a plane perpendicular to the longitudinal axis of said proof mass.
Claim 6
Dependent Claim
63 words
The accelerometer recited in claim 4, wherein said elastic suspension means comprises a plurality of said filaments fixed between said proof mass and said base; and wherein said means for producing a periodic variation of tension in said elastic suspension means comprises a torquing coil mounted on said proof mass and disposed to apply torque to said proof mass about its longitudinal axis.
Claim 7
Dependent Claim
73 words
The accelerometer recited in claim 4, wherein said elastic suspension means comprises: a first plurality of said filaments fixed between said proof mass and said base; a plurality of springs suspended as cantilevers from said base; a second plurality of said filaments, each suspended between said proof mass and a corresponding one of said plurality of cantilevered springs; and means for deflecting said springs to cause a change in tension in said filaments.
Claim 8
Dependent Claim
18 words
The accelerometer recited in claim 6, wherein said means for deflecting said springs comprises a piezo tension changer.
Claim 9
Independent Claim
111 words
A method of suspending a proof mass from a housing in an electromagnetic force rebalance accelerometer, comprising: providing control means for maintaining the position of said proof mass relation to said housing, wherein said control means produces an output signal proportional to acceleration of said proof mass and housing; providing elastic suspension means for maintaining the position of said proof mass relative to said base; producing a periodic variation of stress in said elastic suspension means, whereby a corresponding periodic variation proportional to bias is caused to appear in said output signal; sensing said periodic variation proportional to bias; and using said periodic variation to substantially eliminate or null said bias.
Claim 10
Independent Claim
111 words
A method of suspending a proof mass from a housing in an electromagnetic force rebalance accelerometer, comprising: providing control means for maintaining the position of said proof mass relation to said housing, wherein said control means produces an output signal proportional to acceleration of said proof mass and housing; providing elastic suspension means for maintaining the position of said proof mass relative to said base; producing a periodic variation of stress in said elastic suspension means, whereby a corresponding periodic variation proportional to bias is caused to appear in said output signal; sensing said periodic variation proportional to bias; and using said periodic variation to substantially eliminate or null said bias.
Claim 11
Dependent Claim
26 words
The method recited in claim 8, wherein said elastic suspension means comprises a plurality of filaments held in tension between said proof mass and said housing.
Claim 12
Dependent Claim
31 words
The method recited in claim 9, wherein said step of producing a periodic variation of stress in said elastic suspension means comprises producing a periodic variation of tension in said filaments.
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) | 1986-02-07 | 1986-08-09 | 1987-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-07 | 1990-08-09 | 1991-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-07 | 1994-08-09 | 1995-02-08 | $7700.00 | Window Closed / Lapsed |