IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0604994
(2006-11-28)
|
등록번호 |
US-7415876
(2008-08-26)
|
발명자
/ 주소 |
- Hubbard, Jr.,James E.
- Pullen,David K.
|
출원인 / 주소 |
- Hubbard, Jr.,James E.
- Pullen,David K.
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
1 인용 특허 :
4 |
초록
▼
A pressure sensor includes a pressure sensitive element for sensing a distributed fluid pressure and producing a signal in response. The pressure sensitive element is configured to be mountable on an airfoil or a hydrofoil, for example as a thin film piezoelectric element. The sensor finds applicat
A pressure sensor includes a pressure sensitive element for sensing a distributed fluid pressure and producing a signal in response. The pressure sensitive element is configured to be mountable on an airfoil or a hydrofoil, for example as a thin film piezoelectric element. The sensor finds applications, for example, in measuring lift or drag on the airfoil or hydrofoil.
대표청구항
▼
What is claimed is: 1. A sensor comprising: a pressure sensitive element configured and arranged to, when in use, sense a distributed fluid pressure and produce a signal in response, the pressure sensitive element further being configured to be mountable on a foil along a chord-line of the foil, th
What is claimed is: 1. A sensor comprising: a pressure sensitive element configured and arranged to, when in use, sense a distributed fluid pressure and produce a signal in response, the pressure sensitive element further being configured to be mountable on a foil along a chord-line of the foil, the pressure sensitive element further having a geometry split into chord-wise segments at a portion of a surface of the foil where an angle θ passes through zero, wherein θ is an angle of a tangent to the surface measured in a positive counterclockwise direction from the chord-line, such that the signals produced by each of the chord-wise segments may be processed together to obtain an axial component of the sensed distributed pressure. 2. A sensor as in claim 1, wherein the chord-wise segments comprise an upper-front segment and upper-rear segment mountable on an upper surface of the foil and a lower-front segment and a lower-rear segment mountable on a lower surface of the foil. 3. A sensor as in claim 2, further comprising a processor configured and arranged to receive the signals produced by the segments of the pressure sensitive element and to add a signal from the upper-front segment to a signal from the lower-front segment and to subtract a signal from the upper-rear segment and the lower-rear segment to determine a net axial pressure on the foil. 4. A sensor as in claim 3, further comprising a memory having stored therein machine readable calibration information, and wherein the net axial pressure on the foil is further processed using the calibration information to determine a drag on the foil. 5. A sensor as in claim 1, further comprising a lift sensor, the lift sensor comprising a pressure sensitive element configured and arranged to, when in use, sense the distributed fluid pressure and produce a signal in response such that the signal produced may be processed to obtain a normal component of the sensed distributed pressure. 6. A sensor as in claim 1, wherein the foil comprises an airfoil and the fluid pressure comprises an air pressure. 7. A sensor as in claim 1, wherein the foil comprises a hydrofoil and the fluid pressure comprises a hydraulic pressure. 8. A sensor as in claim 1, wherein the pressure sensitive element comprises a piezoresistive element, and the sensor further comprises a source, configured and arranged to produce a base signal and wherein the signal produced by the piezoresistive element comprises the base signal modulated by a transfer function of the piezoresistive element. 9. A sensor as in claim 1, wherein the pressure sensitive element comprises a piezoelectric element. 10. A sensor as in claim 1, wherein the pressure sensitive element further has a spatially weighted geometry dependent on a geometry of the chord-line of the foil. 11. A sensor as in claim 5, wherein the lift sensor is further divided into a plurality of spatially weighted sub-elements and wherein signals from each of the sub-elements can be processed together to determine at least one parameter of the distributed fluid pressure. 12. A sensor as in claim 11, wherein the at least one parameter comprises a center of pressure. 13. A method of measuring drag on a foil comprising: measuring a distributed fluid pressure on respective upper and lower front surface portions of the foil; measuring a distributed fluid pressure on respective upper and lower rear surface portions of the foil; and subtracting the measured distributed fluid pressure on the rear surface portions from the measured distributed fluid pressure on the front surface portions to obtain a net axial pressure. 14. A method as in claim 13 wherein the foil comprises an airfoil and the fluid pressure is comprises an air pressure. 15. A method as in claim 13 wherein the foil comprises a hydrofoil and the fluid pressure comprises a hydraulic pressure. 16. A method as in claim 13, wherein the measuring comprises using segmented pressure sensitive material, each segment of the segmented pressure sensitive material having a geometry dependent on a geometry of the foil. 17. A method as in claim 16, wherein the geometry comprises a spatial aperture weighted geometry. 18. A method as in claim 13, further comprising: calculating, from the net axial pressure and predetermined calibration coefficients, a drag force acting on the foil. 19. A method as in claim 13, further comprising measuring lift on the foil by: measuring an upward pressure on a lower surface portion of the foil; measuring a downward pressure on an upper surface portion of the foil; and subtracting the downward pressure from the upward pressure to determine a net normal pressure on the foil. 20. A method as in claim 17, further comprising: calculating, from the net axial pressure and predetermined calibration coefficients, a drag force acting on the foil; and calculating, from the net normal pressure and predetermined calibration coefficients, a lift force acting on the foil. 21. A method of designing a pressure sensor mountable on a foil comprising: determining at least one point at which an angle θ passes through zero, wherein θ is an angle of a tangent to a surface of the foil measured in a positive counterclockwise direction from a chord-line of the foil along which the sensor is to be disposed; and splitting the sensor into chord-wise segments at the at least one point.
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