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Patent US4819182A successfully refreshed from Google Patents.
US4819182A
Expired / Lapsed
US
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Method and apparatus for reducing vibration of a helicopter fuselage
Assignee: Westland Group PLC
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Filing: 1987-02-04
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Granted: 1989-04-04
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Expires: 2007-02-04
Abstract
Abstract This invention relates to a method and apparatus for reducing vibration of a helicopter fuselage. The apparatus comprises a plurality of actuators interconnecting parts of the helicopter structure capable of relative motion at an exciting frequency, means to continuously oscillate the actuators at a frequency corresponding to the exciting frequency, a plurality of accelerometers attached to the fuselage for generating signals representative of fuselage dynamic accelerations, and processing means for processing said signals and providing output signals for controlling the phase and magnitude of operation of the actuators. In a described embodiment, one of the relatively movable parts comprises a raft structure carrying the gearbox and engines and attached to the fuselage by a resilient attachment adjacent each of its four corners.
Inventors
- 👤 Stephen P. King
- 👤 Christopher I. Hughes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:05
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/001; F; F16; F16F; F16F7/00; F16F7/10; B64C2027/002
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
113 words
A method of reducing vibration of a structure comprises the steps of connecting a plurality of actuators between parts of the structure capable of relative motion at an exciting frequency, continuously oscillating the plurality of actuators at a frequency substantially corresponding to the exciting frequency, generating signals representative of dynamic accelerations at a plurality of locations on the structure and feeding said signals to on board processing means providing output signals for controlling the phase and magnitude of applied forces generated by the actuators and for varying the phase and magnitude characteristics of said forces so as to compensate for changes in structure dynamics whereby the overall level of structural vibration is reduced.
Claim 2
Independent Claim
113 words
A method of reducing vibration of a structure comprises the steps of connecting a plurality of actuators between parts of the structure capable of relative motion at an exciting frequency, continuously oscillating the plurality of actuators at a frequency substantially corresponding to the exciting frequency, generating signals representative of dynamic accelerations at a plurality of locations on the structure and feeding said signals to on board processing means providing output signals for controlling the phase and magnitude of applied forces generated by the actuators and for varying the phase and magnitude characteristics of said forces so as to compensate for changes in structure dynamics whereby the overall level of structural vibration is reduced.
Claim 3
Dependent Claim
124 words
A helicopter comprising a structure including a main sustaining rotor supporting a fuselage, a plurality of actuators connected between parts of the structure capable of relative motion at a frequency corresponding substantially with a frequency exciting the fuselage to vibrate, power source means continuously oscillating the actuators at a frequency corresponding substantially with the exciting frequency, a plurality of accelerometers attached to the fuselage at selected locations for generating signals representative of fuselage dynamic accelerations, and on board processing means for processing said signals and providing output signals for controlling phase and magnitude of the output forces generated by the actuators and for automatically adjusting the phase and magnitude of the actuator output forces to compensate for changing dynamic characteristics of the helicopter fuselage.
Claim 4
Dependent Claim
124 words
A helicopter comprising a structure including a main sustaining rotor supporting a fuselage, a plurality of actuators connected between parts of the structure capable of relative motion at a frequency corresponding substantially with a frequency exciting the fuselage to vibrate, power source means continuously oscillating the actuators at a frequency corresponding substantially with the exciting frequency, a plurality of accelerometers attached to the fuselage at selected locations for generating signals representative of fuselage dynamic accelerations, and on board processing means for processing said signals and providing output signals for controlling phase and magnitude of the output forces generated by the actuators and for automatically adjusting the phase and magnitude of the actuator output forces to compensate for changing dynamic characteristics of the helicopter fuselage.
Claim 5
Dependent Claim
19 words
A helicopter as claimed in claim 2, wherein said exciting frequency corresponds substantially with the rotor blade passing frequency.
Claim 6
Dependent Claim
22 words
A helicopter as claimed in claim 2, wherein said exciting frequency comprises an instantaneous value from a pre-selected range of exciting frequencies.
Claim 7
Dependent Claim
38 words
A helicopter as claimed in claim 2, wherein one of said relatively movable parts comprises a raft structure carrying the gearbox and engines and attached to the fuselage by a resilient attachment adjacent each of its four corners.
Claim 8
Dependent Claim
16 words
A helicopter as claimed in claim 5, wherein each said resilient attachment comprises an elastomeric unit.
Claim 9
Dependent Claim
18 words
A helicopter as claimed in claim 6, wherein said resilient attachments and said actuators are equal in number.
Claim 10
Dependent Claim
20 words
A helicopter as claimed in claim 7, wherein each said resilient attachment and actuator are integrated in a single unit.
Claim 11
Dependent Claim
13 words
A helicopter as claimed in claim 2, said actuator comprises an electro-hydraulic actuator.
Claim 12
Dependent Claim
20 words
A helicopter as claimed in claim 2, wherein the number of accelerometers is not less than the number of actuators.
Claim 13
Dependent Claim
101 words
Apparatus for reducing vibration of a vehicle structure comprising a plurality of actuators interconnecting parts of the structure capable of relative motion at an exciting frequency, a power source adapted to continuously oscillate the actuators at a frequency corresponding substantially to the exciting frequency, a plurality of accelerometers attached to the structure for generating signals representative of structure dynamic accelerations, and processing means for processing said signals and providing output signals for controlling the phase and magnitude of output forces generated by the actuators and for automatically adjusting the phase and magnitude so as to compensate for changing structural dynamic characteristics.
Claim 14
Dependent Claim
101 words
Apparatus for reducing vibration of a vehicle structure comprising a plurality of actuators interconnecting parts of the structure capable of relative motion at an exciting frequency, a power source adapted to continuously oscillate the actuators at a frequency corresponding substantially to the exciting frequency, a plurality of accelerometers attached to the structure for generating signals representative of structure dynamic accelerations, and processing means for processing said signals and providing output signals for controlling the phase and magnitude of output forces generated by the actuators and for automatically adjusting the phase and magnitude so as to compensate for changing structural dynamic characteristics.
Claim 15
Dependent Claim
14 words
Apparatus as claimed in claim 11, wherein each said actuator comprises an electro-hydraulic actuator.
Claim 16
Dependent Claim
20 words
Apparatus as claimed in claim 11, wherein said relatively movable parts of the structure are attached by resilient attachment means.
Claim 17
Dependent Claim
16 words
Apparatus as claimed in claim 2, wherein each said resilient attachment means comprise an elastomeric unit.
Claim 18
Dependent Claim
17 words
Apparatus as claimed in claim 2, wherein said resilient attachments and said actuators are equal in number.
Claim 19
Dependent Claim
19 words
Apparatus as claimed in claim 15, wherein each said resilient attachment and actuator are integrated in a single unit.
Claim 20
Dependent Claim
19 words
Apparatus as claimed in claim 11, wherein the number of accelerometers is not less than the number of actuators.
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) | 1992-04-03 | 1992-10-03 | 1993-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-03 | 1996-10-03 | 1997-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-03 | 2000-10-03 | 2001-04-04 | $7700.00 | Window Closed / Lapsed |