In-situ load system for calibrating and validating aerodynamic properties of scaled aircraft in ground-based aerospace testing applications
원문보기
IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0191898
(2014-02-27)
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등록번호 |
US-9354134
(2016-05-31)
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발명자
/ 주소 |
- Commo, Sean A.
- Lynn, Keith C.
- Landman, Drew
- Acheson, Michael J.
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출원인 / 주소 |
- THE UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR OF THE NATIONAL AERONAUTICS AND SPACE ADMINSTRATION
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
4 인용 특허 :
4 |
초록
▼
An In-Situ Load System for calibrating and validating aerodynamic properties of scaled aircraft in ground-based aerospace testing applications includes an assembly having upper and lower components that are pivotably interconnected. A test weight can be connected to the lower component to apply a kn
An In-Situ Load System for calibrating and validating aerodynamic properties of scaled aircraft in ground-based aerospace testing applications includes an assembly having upper and lower components that are pivotably interconnected. A test weight can be connected to the lower component to apply a known force to a force balance. The orientation of the force balance can be varied, and the measured forces from the force balance can be compared to applied loads at various orientations to thereby develop calibration factors.
대표청구항
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1. An on-site method of calibrating a force balance in the presence of a gravitational field defining a gravity vector, the method comprising: providing a force balance defining a force balance coordinate system, wherein the force balance is configured to measure applied roll, pitch, and yaw moments
1. An on-site method of calibrating a force balance in the presence of a gravitational field defining a gravity vector, the method comprising: providing a force balance defining a force balance coordinate system, wherein the force balance is configured to measure applied roll, pitch, and yaw moments and axial, side, and normal forces;connecting the force balance to a movable support that is capable of rotating the force balance in at least pitch and roll;utilizing an angle measurement system to measure an angular orientation of the force balance relative to the gravity vector;providing a pivotable connecting assembly having an upper mounting structure that is operably connected to the force balance such that forces applied to the upper mounting structure are transmitted to the force balance wherein the upper mounting structure is pivotably connected to a lower mounting structure by bearings that permit rotation of the lower mounting structure relative to the upper mounting structure in at least pitch and roll;wherein: the upper mounting structure includes a base portion and a pair of spaced apart support structures extending from the base portion;the lower mounting structure includes a base portion and a pair of spaced apart support structures extending from the base portion; andthe pivotable connecting structure further including a bearing cross that is rotatably connected to the support structures of the upper mounting structure by first and second ball bearings, and wherein the bearing cross is rotatably connected to the support structures of the lower mounting structure by third and fourth ball bearings;operably connecting a test weight to the lower mounting structure to thereby apply a known test force to the force balance;comparing force measurements of the force balance to a test force applied to the force balance at a first angular orientation of the force balance relative to the gravity vector;rotating the force balance to a second angular orientation relative to the gravity vector;comparing force measurements of the force balance to a test force applied to the force balance at the second angular position relative to the gravity vectorgenerating calibration factors by comparing the first and second force measurements to the known test force to determine differences between the first and second force measurements and the known test force whereby the calibration factors can be utilized to measure applied loads during aerodynamic testing in a wind tunnel. 2. The method of claim 1, including: providing an aerodynamic model to be tested in a wind tunnel;connecting the upper mounting structure to the aerodynamic model to the force balance such that test forces applied to the pivotable connecting assembly are transmitted through the force balance. 3. The method of claim 2, wherein: the movable support is located in a wind tunnel;the test forces are applied to the aerodynamic model in a wind tunnel. 4. The method of claim 1, including: providing an angle measurement system comprising three accelerometers that are configured to measure the angular orientation of the angle measurement system relative to the gravity vector. 5. The method of claim 4, including: rigidly connecting the angle measurement system to the upper mounting structure. 6. The method of claim 1, wherein: the movable support is positioned in a wind tunnel. 7. A method of calibrating a force balance in a wind tunnel, the method comprising: connecting a force balance to a movable support member in a wind tunnel;utilizing a pivoting connecting assembly having at least two rotational degrees of freedom to connect a test weight to the force balance to thereby apply a known test force to the force balance wherein the pivoting connecting assembly includes upper and lower mounting structures that are pivotably interconnected by a bearing cross and a plurality of bearings to provide at least two degrees of freedom of the lower mounting structure relative to the upper mounting structure;obtaining a first force measurement from the force balance when a known test force is applied to the force balance when the force balance is in a first orientation;obtaining a second force measurement from the force balance when a known test force is applied to the force balance when the force balance is in a second orientation wherein the force balance is rotated relative to the first orientation; andgenerating calibration factors by comparing the first and second force measurements to the known test force to determine differences between the first and second force measurements and the known test force whereby the calibration factors can be utilized to measure applied loads during aerodynamic testing in a wind tunnel. 8. The method of claim 7, wherein: the method is conducted in a gravitational field defining a unitary gravity vector,the known test force defines a load vector having a magnitude and a direction that coincides with a direction of the unitary gravity vector. 9. The method of claim 8, wherein: the force balance defines a balance coordinate system at a balance moment center point;the load vector is applied at a load point that is spaced apart from the balance moment center point to define a distance vector extending between the balance moment center point and the load point; andthe test weight generates applied moments about the balance moment center whereby the applied moments define an applied moment vector that is equal to the vector produce of the distance vector and the load vector. 10. The method of claim 9, wherein: the load vector can be expressed in the balance coordinate system as the product of the magnitude of the load vector and the gravity vector. 11. The method of claim 10, wherein: the wind tunnel defines a generally horizontal primary axis and generates flow in a first direction that is parallel to the primary axis;the balance coordinate system defines a y axis that can be positioned parallel to the primary axis to measure axial forces on an aerodynamic model in the wind tunnel; andthe y axis is not parallel to the primary axis in at least one of the first and second orientations such that the load vector component includes a component that is parallel to the y axis whereby the force balance can be calibrated for measuring axial forces acting parallel to the y axis. 12. The method of claim 7, including: measuring an orientation of the force balance when the force balance is in the first and second orientations. 13. The method of claim 12, including: providing an angle measuring system that utilizes gravitational forces to measure an orientation of the force balance. 14. The method of claim 7, including: connecting an aerodynamic model to the force balance;connecting the pivoting connecting assembly to the aerodynamic model. 15. The method of claim 7, including: connecting a calibration fixture to the force balance;connecting the pivoting connecting assembly to the calibration fixture. 16. A system for calibrating a force balance in the presence of a gravitational field defining a gravity vector, the system comprising: a force balance configured to measure loads including axial force, normal force, side force, pitching moment, rolling moment and yawing moment in a coordinate system defined by the force balance;a test structure connected to the force balance such that loads applied to the test structure can be measured by the force balance;a load bearing assembly including an upper mounting structure secured to the test structure and a lower mounting structure that is pivotably connected to the upper mounting structure and pivots relative to the upper mounting structure in at least pitch and roll, wherein the lower mounting structure includes a connector configured to support a test weight to thereby apply a known force to the force balance in the direction of the gravity vector and wherein the pivoting connecting assembly includes upper and lower mounting structures that are pivotably interconnected by a bearing cross and a plurality of bearings to provide at least two degrees of freedom of the lower mounting structure relative to the upper mounting structure; andan angle measurement system that provides gravitation vector components in the coordinate system of the force balance, whereby at least one of the measured loads can be compared to a known applied load. 17. The system of claim 16, wherein: the test structure comprises an aerodynamic model. 18. The system of claim 16, wherein: The test structure comprises a calibration fixture.
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Levkowitch Michael (Rishon Lezion ILX), Internal balance calibration system and method.
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Parker, Peter A.; Rhew, Ray D.; Johnson, Thomas H.; Landman, Drew, Method of calibrating a force balance.
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Parker, Peter A., Single vector calibration system for multi-axis load cells and method for calibrating a multi-axis load cell.
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Mole Philip J. (4138 Catalina Pl. San Diego CA 92107), Six component wind tunnel balance.
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