A method for measuring elastic deformation in wind tunnel tests using tail-supported structures

Abstract

This invention relates to a method for measuring elastic deformation in wind tunnel tests using a tail-support configuration. The method is implemented using an elastic deformation measurement device, primarily applied to measuring the elastic deformation of test models during wind tunnel testing. The elastic deformation measurement device consists of an industrial camera, an eddy current sensor, a tail support rod of the angle-of-attack mechanism, and a data acquisition computer. This device employs a non-contact measurement method to avoid interference with the test model and can measure the elastic deformation of the model in real time during the test. This measurement data can be used to correct the angle-of-attack parameters of the test model in real time, ensuring the accuracy of the wind tunnel test results.

Description

Technical Field

[0001] This invention relates to the field of aerodynamic testing, and more specifically to a method for measuring elastic deformation in wind tunnel tests using a tail-supported configuration. Background Technology

[0002] Conventional aircraft models are typically mounted on a motor-driven angle-of-attack mechanism via a tail support. Multiple motors drive the model to achieve its angle of attack and sideslip angle movements. Wind tunnel testing has revealed that due to the model's weight and aerodynamic forces, the deformation of the tail support and balance at the end of the angle-of-attack mechanism is substantial and cannot be ignored. To ensure the high accuracy of wind tunnel test data, it is necessary to measure the model's elastic deformation.

[0003] Currently, conventional methods for measuring elastic deformation of wind tunnel test models with tail supports include measurements using sensors embedded inside the model and calibration under load. The method of embedding sensors inside the model cannot cover all wind tunnel models, especially some smaller models with complex manufacturing processes. The calibration under load method typically cannot measure deformation errors in the sideslip direction and inevitably introduces nonlinear errors. Summary of the Invention

[0004] The technical problem solved by this application is to overcome the shortcomings of the prior art and propose a tail-supported wind tunnel test elastic deformation measurement method that is not limited by the size of the model and can measure the elastic deformation in the sideslip angle direction and the elastic deformation in the angle of attack direction.

[0005] The technical solution of this application is:

[0006] A method for measuring elastic deformation in a wind tunnel test using a tail-support configuration, implemented through a measuring device, includes:

[0007] The signal acquisition computer acquires measurement data of the output signals of the angle of attack measurement industrial camera, the sideslip angle measurement industrial camera, and the eddy current sensor in both non-experimental and experimental states.

[0008] Based on the measurement data, the physical distance coefficient k corresponding to the camera pixels of the angle of attack measurement industrial camera and the sideslip angle measurement industrial camera is calculated, and the elastic deformation L1 in the angle of attack direction and the elastic deformation L2 in the sideslip angle direction of the aircraft model are calculated based on k.

[0009] The measuring device includes a tail support rod, one end of which is connected to the angle-of-attack mechanism adapter, and the other end is connected to the aircraft model via a force balance;

[0010] Both the angle-of-attack measuring industrial camera and the sideslip measuring industrial camera are mounted on the surface of the tail support rod. The measuring axes of the angle-of-attack measuring industrial camera and the sideslip measuring industrial camera are parallel to the axis of the tail support rod. The angle-of-attack measuring industrial camera is mounted on the upper or lower surface of the tail support rod in the vertical direction, and the sideslip measuring industrial camera is mounted on the left or right surface of the tail support rod in the vertical direction.

[0011] An eddy current sensor is mounted on the tail boom and faces the tail of the aircraft model in a direction perpendicular to the tail boom axis.

[0012] In non-experimental conditions, the signal acquisition computer acquires the output signals of the angle of attack measurement industrial camera, the sideslip angle measurement industrial camera, and the eddy current sensor to obtain the vertex pixel (x1, y1) at the vertical end of the tail arc of the aircraft model, the vertex pixel (x2, y2) at the horizontal end of the tail arc of the aircraft model, the pixel difference y3 between a point on the tail arc of the aircraft model directly opposite the surface of the eddy current sensor and the surface of the eddy current sensor, and the measurement distance h1 of the output signal of the eddy current sensor.

[0013] In the experimental state, the signal acquisition computer collects the output signals of the angle of attack measurement industrial camera, the sideslip angle measurement industrial camera, and the eddy current sensor, and obtains the vertex pixel (x4, y4) at the vertical end of the tail arc of the aircraft model, the vertex pixel (x5, y5) at the horizontal end of the tail arc of the aircraft model, the vertical pixel difference y6 between a point on the tail arc of the aircraft model directly opposite the surface of the eddy current sensor and the upper surface of the eddy current sensor, and the measurement distance h2 of the output signal of the eddy current sensor.

[0014] The K = (h1-h2) / (y3-y6).

[0015] The elastic deformation of the aircraft model in the direction of angle of attack is L1 = K*(y1-y4).

[0016] The elastic deformation of the aircraft model in the sideslip direction is L2 = K*(y2-y5).

[0017] The signal acquisition computer acquires the output signals of the angle-of-attack measurement industrial camera and the sideslip angle measurement industrial camera to obtain the images from the angle-of-attack measurement industrial camera and the sideslip angle measurement industrial camera.

[0018] The image from the industrial camera used for angle of attack measurement is segmented into regions. The segmented images are then subjected to arc recognition. The minimum vertical pixel value on the recognized arc curve is selected to obtain the pixels in the original acquired image that are located in the vertical direction of the arc of the tail plane of the aircraft model.

[0019] The imaging of the industrial camera for sideslip angle measurement is segmented into regions. The segmented images are then subjected to arc recognition. The minimum pixel value in the lateral direction on the recognized arc curve is selected to obtain the pixels in the lateral direction of the arc at the tail end of the aircraft model that are in the original acquired image.

[0020] The eddy current sensor is used in industrial camera imaging for angle of attack measurement or in industrial camera imaging for sideslip angle measurement.

[0021] Specifically, when the eddy current sensor is used in the imaging of the angle of attack measurement industrial camera, and the surface of the eddy current sensor is perpendicular to the vertical direction, the vertical pixels on the surface of the eddy current sensor are manually selected in the imaging of the angle of attack measurement industrial camera, and the difference between the vertical vertex of the arc of the tail plane of the aircraft model and the vertical pixel of the eddy current sensor surface is calculated.

[0022] When an eddy current sensor is used in the imaging of an industrial camera for sideslip angle measurement, and the surface of the eddy current sensor is perpendicular to the lateral direction, the vertical pixels on the surface of the eddy current sensor are manually selected in the imaging of the industrial camera for sideslip angle measurement, and the difference between the lateral vertex of the arc of the tail plane of the aircraft model and the vertical pixel difference on the surface of the eddy current sensor is calculated.

[0023] The industrial camera for measuring angle of attack and the industrial camera for measuring sideslip angle have the same number of pixels.

[0024] In the non-test state, the tail support rod is supported by a support device. In the test state, the support device for the tail support rod is removed.

[0025] The vertex at the vertical end is either the top vertex or the bottom vertex; the vertex at the horizontal end is either the left vertex or the right vertex.

[0026] The vertical direction is the vertical direction; the horizontal direction is the horizontal direction that is parallel to the plane at the tail end of the aircraft model.

[0027] Furthermore, the pixels obtained from the angle-of-attack measurement industrial camera are represented based on the angle-of-attack measurement industrial camera coordinate system, and the pixels obtained from the sideslip angle measurement industrial camera are represented based on the sideslip angle measurement industrial camera coordinate system.

[0028] In summary, this application includes at least the following beneficial technical effects:

[0029] (1) The present invention provides a tail support wind tunnel test model elastic deformation measurement device, which is designed with real-time acquisition and calculation function, and can measure the elastic deformation of the aircraft model in the direction of angle of attack and sideslip angle in real time.

[0030] (2) The present invention does not require the installation of sensors inside the aircraft model, and adopts a non-contact measurement method, thus eliminating the interference of the measurement device on the aircraft model.

[0031] (3) The present invention moves synchronously with the model during wind tunnel testing, eliminating measurement errors caused by model movement, and can realize real-time elastic deformation measurement throughout the entire angle of attack range.

[0032] (4) The present invention adopts a direct measurement method to eliminate the nonlinear interference caused by the traditional method of measuring elastic deformation by loading calibration. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall invention;

[0034] Figure 2 This is a schematic diagram of the tail support rod of the present invention;

[0035] Figure 3 This is an image captured by the angle-of-attack measurement camera of the present invention;

[0036] Figure 4 This is an image captured by the side-slip angle camera of the present invention.

[0037] Explanation of reference numerals in the attached drawings: 1. Tail support rod; 11. First groove; 12. Second groove; 13. Long slot hole; 2. Industrial camera for measuring angle of attack; 3. Industrial camera for measuring sideslip angle; 4. Eddy current sensor; 5. Signal acquisition computer; 6. Angle of attack mechanism adapter; 7. Force balance; 8. Aircraft model. Detailed Implementation

[0038] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments:

[0039] In the following embodiments, the vertical direction is the vertical direction, and the horizontal direction is the horizontal direction that is parallel to the tail plane of the aircraft model.

[0040] This application discloses a method for measuring elastic deformation in a wind tunnel test using a tail-support configuration, comprising the following steps:

[0041] 1. In non-experimental conditions, the tail support rod 1 is supported by a support device, and the force balance 7 and the aircraft model 8 are installed. At this time, the deformation caused by the weight of the aircraft model 8 itself is negligible. The signal acquisition computer 5 acquires the output signals from the angle-of-attack measurement industrial camera 2, the sideslip angle measurement industrial camera 3, and the eddy current sensor 4. The image from the angle-of-attack measurement industrial camera is as follows: Figure 3 As shown, the side slip angle measurement industrial camera imaging is as follows: Figure 4 As shown.

[0042] Among them, such as Figure 1 and Figure 2As shown, the rear end of the tail support rod 1 is fixed to the angle-of-attack mechanism adapter 6, and the front end of the tail support rod 1 is connected to the aircraft model 8 via a force balance 7. The angle-of-attack measurement industrial camera 2, the sideslip angle measurement industrial camera 3, and the eddy current sensor 4 are all mounted on the tail support rod 1. The signal acquisition computer 5 is used to read the output signals of the angle-of-attack measurement industrial camera 2, the sideslip angle measurement industrial camera 3, and the eddy current sensor 4.

[0043] like Figure 1 and Figure 2 As shown, the measuring axes of the angle-of-attack measuring industrial camera 2 and the sideslip measuring industrial camera 3 are parallel to the axis of the tail support rod 1. The upper and side surfaces of the rear end of the tail support rod 1 have a first groove 11 for mounting the angle-of-attack measuring industrial camera 2 and a second groove 12 for mounting the sideslip measuring industrial camera 3, respectively. The first groove 11 and the second groove 12 are aligned at both ends along the axial direction of the tail support rod 1 and have the same depth. They are symmetrically installed along the axis of the tail support rod 1, so that the plane formed by the measuring axis of the angle-of-attack measuring industrial camera 2 and the axis of the tail support rod 1 is perpendicular to the plane formed by the measuring axis of the sideslip measuring industrial camera 3 and the axis of the tail support rod 1.

[0044] The angle-of-attack measuring industrial camera 2 has a first adapter plate connected to its bottom, which is fixedly connected to the bottom of the first groove 11. The side-slip angle measuring industrial camera 3 has a second adapter plate connected to its bottom, which is fixedly connected to the bottom of the second groove 12. Threaded holes are provided at the four inner corners of the bottom of the first groove 11 and the second groove 12 for mechanically fixing them to the first and second adapter plates using bolts. The angle-of-attack measuring industrial camera 2 and the side-slip angle measuring industrial camera 3 have the same pixel count.

[0045] In this embodiment, the angle-of-attack measurement industrial camera 2 faces the upper part of the tail plane of the aircraft model 8 and is used to acquire the vertex pixels of the arc on the tail plane of the aircraft model 8; the sideslip angle measurement industrial camera 3 faces the right side of the tail plane of the aircraft model 8 and is used to acquire the right vertex pixels of the arc on the tail plane of the aircraft model 8. The angle-of-attack measurement industrial camera 2 and the sideslip angle measurement industrial camera 3 are positioned in the same direction along the axis of the tail support 1. The images obtained by the angle-of-attack measurement industrial camera 2 and the sideslip angle measurement industrial camera 3 are shown in the figure below. Figure 3 and Figure 4 As shown.

[0046] like Figure 1 and Figure 2As shown, the eddy current sensor 4 faces the tail of the aircraft model 8 along a direction perpendicular to the axis of the tail support 1. A long slot 13, 10cm in length, is vertically penetrating the tail support 1 at its front end along the horizontal axis. The eddy current sensor 4 is inserted into the long slot 13, and a fixing nut is threaded to both its upper and lower ends. Flat grooves are formed at both ends of the long slot 13 on the tail support 1, and the fixing nuts fit snugly against the bottom of these grooves. Along the axis of the tail support 1, the length of the long slot 13 is greater than the width of the eddy current sensor 4 along the same axis. Tightening the fixing nuts locks the eddy current sensor 4 in place; loosening them allows the eddy current sensor 4 to be adjusted back and forth within the long slot 13, ensuring that the measuring surface of the eddy current sensor 4 is at the upper apex of the tail of the aircraft model 8.

[0047] 2. First, the image from the angle-of-attack measurement industrial camera is segmented to ensure that the tail of the aircraft is filled with the segmented image. The segmented image is then subjected to arc recognition to ensure that other misidentifications are eliminated. The minimum vertical pixel value on the arc curve of the tail plane of aircraft model 8 is selected as the pixel (x1, y1) on the arc curve of the tail plane of aircraft model 8 that is located in the original acquired image.

[0048] Specifically, the pixels obtained from the angle-of-attack measurement industrial camera are represented based on the coordinate system of angle-of-attack measurement industrial camera 2. For the coordinate system of angle-of-attack measurement industrial camera 2, the direction from the bottom of angle-of-attack measurement industrial camera 2 to its axis is defined as the y-direction of angle-of-attack measurement industrial camera 2, and the x-direction of angle-of-attack measurement industrial camera 2 is parallel to the tail plane of the aircraft model and perpendicular to its y-direction. The pixels obtained from the sideslip angle measurement industrial camera are based on the coordinate system of sideslip angle measurement industrial camera 3. For the coordinate system of sideslip angle measurement industrial camera 3, the direction from the bottom of sideslip angle measurement industrial camera 3 to its axis is defined as the y-direction of sideslip angle measurement industrial camera 3, and the x-direction of sideslip angle measurement industrial camera 3 is parallel to the tail plane of the aircraft model and perpendicular to its y-direction. Because both the angle-of-attack measuring industrial camera 2 and the side-slip angle measuring industrial camera 3 are connected to the tail support rod 1 at the bottom, and the installation positions of the angle-of-attack measuring industrial camera 2 and the side-slip angle measuring industrial camera 3 on the tail support rod 1 are at a 90-degree angle, there is a 90-degree angle between the y-direction of the side-slip angle measuring industrial camera 3 and the y-direction of the angle-of-attack measuring industrial camera 2.

[0049] 3. Secondly, in the imaging of the industrial camera 2 for angle of attack measurement, the vertical pixel P on the upper surface of the eddy current sensor 4 is obtained by manually selecting points, and the vertical pixel difference y3 between the vertex on the arc of the tail plane of the aircraft model 8 and the upper surface of the eddy current sensor 4 is calculated.

[0050] 4. Next, the signal acquisition computer 5 acquires the output signal of the eddy current sensor 4 and calculates the measurement distance h1.

[0051] 5. Repeat step 2 to perform image recognition and processing on the image captured by the industrial camera 3 for measuring the sideslip angle, and obtain the right vertex pixel (x2, y2) of the arc at the tail end of the aircraft model 8.

[0052] 6. Under test conditions, remove the support device and repeat the acquisition procedure of signal acquisition computer 5 in steps 1-5. Signal acquisition computer 5 acquires the vertex pixel (x4, y4) on the arc of the tail end plane of aircraft model 8, the right vertex pixel (x5, y5) on the arc of the tail end plane of aircraft model 8, the vertical pixel difference y6 between the vertex on the arc of the tail end plane of aircraft model 8 and the upper surface of eddy current sensor 4, and the measurement distance h2 of the signal output by eddy current sensor 4.

[0053] 7. After the above two steps, the physical distance coefficient k corresponding to the camera pixels of the angle of attack measuring industrial camera 2 and the sideslip angle measuring industrial camera 3 can be calculated, K = (h1-h2) / (y3-y6); the elastic deformation L1 in the angle of attack direction is calculated, L1 = K*(y1-y4). Since the aircraft model 8 is symmetrically installed on the tail support rod 1, the coefficient k can also be used to calculate the elastic deformation L2 in the sideslip angle direction, L2 = K*(y2-y5).

[0054] 8. Image recognition technology can be used to identify the pixel information of the apex and right apex of the tail arc of aircraft model 8 in real time, so as to realize the real-time measurement and calculation of elastic deformation.

[0055] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0056] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims of the present invention.

Claims

1. A method for measuring elastic deformation in a wind tunnel test using a tail-support configuration, characterized in that: This is achieved through a measuring device, and the measuring method includes... The signal acquisition computer (5) acquires the output signals of the angle of attack measurement industrial camera (2), the sideslip angle measurement industrial camera (3), and the eddy current sensor (4) in non-experimental and experimental states. The physical distance coefficient k corresponding to the camera pixels of the angle of attack measurement industrial camera (2) and the sideslip angle measurement industrial camera (3) is calculated based on the measurement data, and the elastic deformation L1 of the aircraft model (8) in the angle of attack direction and the elastic deformation L2 of the aircraft model (8) in the sideslip angle direction are calculated based on k. The measuring device includes a tail support rod (1), one end of which is connected to the angle of attack mechanism adapter (6), and the other end is connected to the aircraft model (8) through a force balance (7). Angle of attack measuring industrial camera (2) and side slip angle measuring industrial camera (3) are both installed on the surface of tail support rod (1). The measuring axes of angle of attack measuring industrial camera (2) and side slip angle measuring industrial camera (3) are parallel to the axis of tail support rod (1). Angle of attack measuring industrial camera (2) is installed on the upper or lower surface of tail support rod (1) in the vertical direction. Side slip angle measuring industrial camera (3) is installed on the left or right surface of tail support rod (1) in the vertical direction. An eddy current sensor (4) is mounted on the tail strut (1) and faces the tail of the aircraft model (8) in a direction perpendicular to the axis of the tail strut (1); In non-test state, the signal acquisition computer (5) acquires the output signals of the angle of attack measurement industrial camera (2), the sideslip angle measurement industrial camera (3), and the eddy current sensor (4), and obtains the vertex pixel (x1, y1) at the vertical end of the tail plane arc of the aircraft model (8), the vertex pixel (x2, y2) at the horizontal end of the tail plane arc of the aircraft model (8), the pixel difference y3 between a point on the tail plane arc of the aircraft model (8) directly opposite the surface of the eddy current sensor (4) and the surface of the eddy current sensor (4), and the measurement distance h1 of the output signal of the eddy current sensor (4); Under test conditions, the signal acquisition computer (5) acquires the output signals of the angle of attack measurement industrial camera (2), the sideslip angle measurement industrial camera (3), and the eddy current sensor (4), and obtains the vertex pixel (x4, y4) at the vertical end of the tail plane arc of the aircraft model (8), the vertex pixel (x5, y5) at the horizontal end of the tail plane arc of the aircraft model (8), the vertical pixel difference y6 between a point on the tail plane arc of the aircraft model (8) directly opposite the surface of the eddy current sensor (4) and the upper surface of the eddy current sensor (4), and the measurement distance h2 of the output signal of the eddy current sensor (4); The value of k is (h1-h2) / (y3-y6); The elastic deformation of the aircraft model (8) in the direction of attack is L1=k*(y1-y4); The elastic deformation of the aircraft model (8) in the sideslip direction is L2=k*(y2-y5).

2. The method for measuring elastic deformation in a wind tunnel test using a tail-supported configuration according to claim 1, characterized in that: The signal acquisition computer (5) acquires the output signals of the angle of attack measurement industrial camera (2) and the sideslip angle measurement industrial camera (3) to obtain the image of the angle of attack measurement industrial camera and the image of the sideslip angle measurement industrial camera; The image of the industrial camera for angle of attack measurement is segmented into regions. The segmented image is then subjected to arc recognition. The minimum pixel value in the vertical direction on the recognized arc curve is selected to obtain the pixel value at one end of the vertical direction of the arc plane at the tail end of the aircraft model (8). The image of the industrial camera for measuring the sideslip angle is segmented, and the segmented image is subjected to arc recognition. The minimum pixel value in the horizontal direction on the recognized arc curve is selected to obtain the pixel at one end of the horizontal direction of the arc on the tail plane of the aircraft model (8).

3. The method for measuring elastic deformation in a wind tunnel test using a tail-supported configuration according to claim 2, characterized in that: The eddy current sensor (4) is used in the imaging of an industrial camera for angle of attack measurement or in the imaging of an industrial camera for sideslip measurement.

4. The method for measuring elastic deformation in a wind tunnel test using a tail-supported configuration according to claim 1, characterized in that: The angle-of-attack measurement industrial camera (2) and the sideslip angle measurement industrial camera (3) have the same number of camera pixels.

5. The method for measuring elastic deformation in a wind tunnel test using a tail-support configuration according to claim 1, characterized in that: In the non-test state, the tail support rod (1) is supported by a support device.

6. The method for measuring elastic deformation in a wind tunnel test using a tail-supported configuration according to claim 5, characterized in that: Under the test conditions, the support device of the tail support rod (1) is removed.

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