Elastic deformation testing system of continuous wind tunnel model and elastic effect correction method

Abstract

The elastic deformation test system and elastic effect correction method of the continuous wind tunnel model belong to the field of wind tunnel model testing technology. In order to accurately simulate the influence of deformation on aerodynamic force, the first image acquisition device of the present invention is fixed in the first air-cooled pressure-stabilizing cabin through the first fixed block, and the second image acquisition device is fixed in the second air-cooled pressure-stabilizing cabin through the second fixed block. Multiple light sources are installed on the side wall of the wind tunnel test section; the first air-cooled pressure-stabilizing cabin and the second air-cooled pressure-stabilizing cabin are fixedly installed on the upper surface of the wind tunnel test section; before the elastic deformation test of the continuous wind tunnel model, the wind tunnel axis calibration device is placed in the wind tunnel test section to calibrate the wind tunnel axis, and then the wind tunnel axis calibration device is replaced with the model to be tested to perform the elastic deformation test of the continuous wind tunnel model; a checkerboard calibration plate is embedded in the table of the wind tunnel axis calibration device, and the first angle measuring instrument and the second angle measuring instrument are placed on the table, and a support rod is installed on the side surface of the table. The present invention improves the matching accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind tunnel model testing, and in particular relates to an elastic deformation testing system and an elastic effect correction method for a continuous wind tunnel model. Background Art

[0002] In modern fluid mechanics research, wind tunnel testing is a key means of analyzing and optimizing aerodynamic performance. The accuracy of wind tunnel models is particularly crucial for the study of complex flow fields and multi-deformation objects. However, the models used in traditional wind tunnel tests usually assume that the object is a rigid structure, ignoring the elastic deformation effects that may occur when the model is subjected to airflow. This assumption may be inaccurate in certain high-speed, high-pressure, or highly complex flow fields, resulting in large deviations between the calculated results and the actual situation. Therefore, how to accurately simulate the elastic effects of objects subjected to airflow in wind tunnel tests has become an urgent problem to be solved in the field of fluid mechanics.

[0003] With the continuous development of computational fluid dynamics (CFD) technology, the integration of numerical simulation and physical experiments has become a key research direction in modern fluid dynamics. When solving large-scale deformations, nonlinear aerodynamic characteristics, and high-precision models, rigid models often fail to accurately reflect the aerodynamic characteristics and actual performance of an object. Therefore, the research and development of effective methods to correct for elastic effects is of great practical significance for improving the accuracy of wind tunnel experiments and numerical simulation results.

[0004] When correcting for elastic effects, simultaneous measurement of attitude and deformation is crucial and requires high precision. To accurately capture the aerodynamic response of the model as it deforms in the wind tunnel, the model's attitude changes and deformation state must be measured simultaneously in real time. Due to the wide range of model attitude variations, some markers may be invisible or obscured in specific attitudes. As the model undergoes significant attitude changes in the wind tunnel, some markers may drift out of view or become unavailable to the camera due to changes in their geometric position. This increases the difficulty of marker matching, compromising accurate attitude matching and elastic effect correction.

[0005] To ensure the accuracy of elastic correction, the placement strategy of wing markers becomes a key challenge. Since interpolation processing is required later, improper placement of markers can lead to reduced interpolation accuracy, affecting the accuracy and computational efficiency of the correction results. Summary of the Invention

[0006] The problem to be solved by the present invention is to accurately simulate the influence of deformation on aerodynamic force, and propose an elastic deformation testing system of a continuous wind tunnel model and an elastic effect correction method.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions:

[0008] A continuous wind tunnel model elastic deformation testing system includes a first image acquisition device, a second image acquisition device, a first air-cooled pressure stabilizing cabin, a second air-cooled pressure stabilizing cabin, a first fixing block, a second fixing block and a light source;

[0009] The first image acquisition device is fixed in the first air-cooled pressure-stabilizing cabin via a first fixing block, and the second image acquisition device is fixed in the second air-cooled pressure-stabilizing cabin via a second fixing block. The plurality of light sources are mounted on the side wall of the wind tunnel test section; the first air-cooled pressure-stabilizing cabin and the second air-cooled pressure-stabilizing cabin are fixedly mounted on the upper surface of the wind tunnel test section;

[0010] Before the elastic deformation test of the continuous wind tunnel model, the wind tunnel shaft system calibration device is placed in the wind tunnel test section to calibrate the wind tunnel shaft system, and then the wind tunnel shaft system calibration device is replaced with the model to be tested to perform the elastic deformation test of the continuous wind tunnel model;

[0011] The wind tunnel shaft system calibration device includes a support rod, a first angle measuring instrument, a second angle measuring instrument, a checkerboard calibration plate and a table. The checkerboard calibration plate is embedded in the table. The first angle measuring instrument and the second angle measuring instrument are placed in the horizontal and vertical directions on the table respectively. The side surface of the table is installed with a support rod, and the wind tunnel shaft system calibration device is moved to multiple positions of the model to be tested during the wind tunnel test through the support rod.

[0012] Furthermore, the table of the wind tunnel shaft system calibration device is connected to the support rod through a flange.

[0013] Furthermore, the first image acquisition device includes a camera and a lens, and the second image acquisition device includes a camera and a lens. When the brightness of the marked point excites a light source of a specific band, an optical filter that selectively transmits the excitation band and effectively filters out light of other bands is configured in front of the lens.

[0014] A method for correcting elastic effects of a continuous wind tunnel model is implemented based on an elastic deformation testing system of a continuous wind tunnel model and includes the following steps:

[0015] S1. Arrangement of a continuous wind tunnel model elastic deformation test system;

[0016] S2. Calibrate the elastic deformation test system of a continuous wind tunnel model using a wind tunnel axis calibration device, including calibration of camera parameters and wind tunnel axis calibration;

[0017] S3. Arrange markers on the model to be tested, arrange markers on the fuselage of the model to be tested for posture recognition, and arrange markers on the wing portion of the model to be tested for identifying elastic deformation of the wing;

[0018] S4 uses the first image acquisition device, the second image acquisition device to acquire images, collect the reference image and test image of the model to be tested;

[0019] S5. Marker point recognition and matching of the reference image and test image of the model to be tested collected in step S4;

[0020] S6. Calculate the deformation and current posture of the wing of the test model under different working conditions;

[0021] S7. Correct the effects of elastic deformation on the model under test.

[0022] Furthermore, the specific implementation method of step S2 includes the following steps:

[0023] S2.1. By adjusting the support rods, the table is placed at various positions of the model under test during the wind tunnel test. Images of the checkerboard calibration plate are captured using the first and second image acquisition devices. The camera's intrinsic and extrinsic parameters are calculated using the Zhang calibration method.

[0024] S2.2. Wind tunnel axis calibration: By adjusting the angle of the wind tunnel mechanism support rod, the first image acquisition device and the second image acquisition device are used to collect images of the calibration plate at different pitch angles. The image coordinates of the corner points of the calibration plate images are obtained based on the corner point detection. and external reference The three-dimensional coordinates of the corner points of the checkerboard calibration plate at different pitch angles are obtained. The rotation relationship between the three-dimensional coordinates of the corner points of the two adjacent pitch angle checkerboards is calculated by the Genro-Kabsch algorithm. The rotation relationship is converted into an axis vector by the Rodrigues transformation. The average is obtained to obtain the pitch axis vector of the model to be tested in the wind tunnel axis system. The vector modulus is normalized to 1 to obtain the final pitch axis vector. ; Then calculate the yaw axis vector , roll axis vector ; Get the wind tunnel axis transformation matrix of the camera coordinate system , the expression is:

[0025] .

[0026] Furthermore, the specific implementation method of step S3 includes the following steps:

[0027] S3.1. Arrange markers on the fuselage of the model to be tested, using an irregular distribution strategy to prevent multiple markers from falling on the same epipolar line. This ensures that marker matching can be effectively achieved under epipolar constraints from different viewing angles.

[0028] S3.2. Place markers on the wing of the model to be tested. Use a regular distribution strategy to place markers at the wing root, leading edge, and trailing edge. Ensure that the markers are evenly distributed in the spanwise and chordwise directions to identify the elastic deformation of the wing.

[0029] Furthermore, the specific implementation method of step S4 includes the following steps:

[0030] S4.1. Collect baseline images of the model to be tested: Collect image sequences of all working conditions in the absence of wind, and image sequences collected by the first image acquisition device in the absence of wind , Image sequence captured by the second image acquisition device when there is no wind , where m is the number of working conditions, is the image captured by the first image acquisition device in the mth working condition when there is no wind, The image captured by the second image acquisition device in the mth working condition when there is no wind, and the posture information sequence when there is no wind is recorded and the image captured by the first image acquisition device when the posture of the model to be tested is 0 in the absence of wind , the image captured by the second image acquisition device ,in is the attitude information of the mth working condition when there is no wind;

[0031] S4.2. Collect test images of the model to be tested: Collect image sequences of all working conditions during the test. The image sequence collected by the first image acquisition device during the test is , the image sequence captured by the second image acquisition device during the test , n is the number of working conditions during the test, and the posture information sequence during the test is recorded , set m greater than or equal to n, where is the image captured by the first image acquisition device of the nth working condition during the test, is the image captured by the second image acquisition device of the nth working condition during the test, is the posture information of the nth working condition during the test.

[0032] Furthermore, the specific implementation method of step S5 includes the following steps:

[0033] S5.1. Identify and match the same-name markers in the image captured by the first image acquisition device and the second image acquisition device, including fuselage marker matching and wing marker matching;

[0034] S5.1.1. Match the fuselage markers using epipolar constraints to obtain the matching fuselage marker sequence in the absence of wind.

[0035] S5.1.2. Wing marker point matching is mainly performed through image correlation to obtain the matching wing marker point sequence in the absence of wind. , where l is the number of marking points on the wing, is the image coordinate of the lth marking point on the wing in the image captured by the first image acquisition device, The image coordinates of the lth marking point on the wing in the image captured by the second image acquisition device;

[0036] S5.1.3. Combining the camera internal and external parameters obtained in step S2 , through triangulation, reconstruct the 3D coordinates of the fuselage marker points matched in no wind The three-dimensional coordinates of the wing marker points matched with the no-wind ;

[0037] S5.1.4. Wind tunnel axis transformation matrix obtained in S2 , get the three-dimensional coordinate sequence of the fuselage in the wind tunnel coordinate system when there is no wind And the three-dimensional coordinate sequence of the wing marker point in the wind tunnel coordinate system when there is no wind ;

[0038] S5.2. Perform matching of marker points under all working conditions and marker points when the posture is 0 in the image captured by the first image acquisition device and the second image acquisition device, including fuselage marker point matching and wing marker point matching;

[0039] S5.2.1. The fuselage markers are matched using a 3D point cloud matching method based on distance matching and singular value decomposition. The matching result sequence of the markers under any test condition on the fuselage and the markers when the posture is zero is obtained. ;

[0040] S5.2.2. The wing markers are matched in two dimensions based on image correlation and then converted to three-dimensional coordinates in the wind tunnel coordinate system. The matching sequence of the wing markers under any test condition and the markers at attitude 0 is obtained, as well as the markers under the corresponding condition in no wind. .

[0041] Furthermore, the specific implementation method of step S6 includes the following steps:

[0042] S6.1. For the hth load case, h , calculate the attitude of the wing of the model to be tested. Based on the rigid body assumption, the expression is:

[0043] ;

[0044] in, for and The rotation matrix of the transformation between for and The translation vector between the transformations;

[0045] Solve by calculating the generalized inverse matrix or by using singular value decomposition and , the expression is:

[0046] ;

[0047] ;

[0048] in, - They correspond to the elements of the 1st row and 1st column, the 2nd row and 1st column, the 3rd row and 1st column, the 1st row and 2nd column, the 2nd row and 2nd column, the 3rd row and 2nd column, the 1st row and 3rd column, the 2nd row and 3rd column, and the 3rd row and 3rd column of the rotation matrix respectively. - Represents the first, second, and third components of the translation vector;

[0049] Will Convert to pitch angle , yaw angle , roll angle , 、 、 ;

[0050] Then the posture sequence of all test conditions is obtained ;

[0051] S6.2. For the hth load case, h , calculate the deformation of the wing of the model to be tested;

[0052] for ,calculate arrive The rotation matrix and the translation matrix, then the three-dimensional coordinates of the h-th working condition wing marker point aligned to the zero attitude without wind are + , the three-dimensional coordinates of the h-th working condition wing mark point during the test are + , then the deformation of the marked point in the model coordinate system is - ;

[0053] Then the wing deformation of all working conditions is obtained .

[0054] Furthermore, the specific implementation method of step S7 includes the following steps:

[0055] S7.1. Aerodynamic calculation of the original rigid model: Use PointWise software to generate an unstructured hybrid mesh of the model to be tested before deformation. Import the mesh into the CFD solver. Input the attitude information of the model to be tested, set the incoming flow conditions, and solve the flow field to obtain the aerodynamic coefficients such as lift and drag of the model to be tested before deformation;

[0056] S7.2. Select interpolation points on the mesh surface of the model to be measured, based on , interpolate to obtain the deformed surface mesh of the model to be tested, and then use the mesh deformation program to automatically generate the deformed mesh of the model;

[0057] S7.3. Calculate the aerodynamic forces of the deformed model using a CFD solver to correct for the effects of elastic deformation. Compare the aerodynamic forces with those before deformation to determine the effect of elastic deformation on the aerodynamic forces.

[0058] Beneficial effects of the present invention:

[0059] The present invention provides a method for correcting the elastic effects of a continuous wind tunnel model. By building a deformation measurement system suitable for continuous wind tunnel testing and combining it with advanced equipment such as high-speed cameras, air-cooled pressure chambers, and light sources, it achieves real-time, high-precision measurement of model deformation. To ensure the accuracy of the measurement data, a marker point placement strategy is specifically designed to optimize the geometric distribution during the data acquisition process. This method accurately aligns images from different perspectives or different working conditions, significantly improving the accuracy of image-related calculations. During the marker point matching process, a three-dimensional point cloud optimization algorithm based on distance matching and singular value decomposition (SVD) is used to ensure accurate matching of marker points in different postures, thereby achieving simultaneous, high-precision measurement of posture and deformation.

[0060] The present invention provides a method for correcting the elastic effects of a continuous wind tunnel model. By using precise measurement results, the aerodynamic grid is further updated and corrected, successfully achieving accurate correction of the model's elastic effects, thereby providing more reliable aerodynamic characteristics and optimized design basis for wind tunnel test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 Schematic diagram of the structure of an elastic deformation testing system for a continuous wind tunnel model of the present invention;

[0062] Figure 2 Schematic diagram of the wind tunnel shafting calibration device of the present invention;

[0063] Figure 3The figure is a flow chart of a method for correcting elastic effects of a continuous wind tunnel model according to the present invention. DETAILED DESCRIPTION

[0064] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. That is, the specific embodiments described herein are only some embodiments of the present invention, not all embodiments. Generally, the components of the specific embodiments of the present invention described and illustrated in the drawings herein can be arranged and designed in various different configurations, and the present invention can also have other embodiments.

[0065] Therefore, the following detailed description of the specific embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely representative of selected specific embodiments of the present invention. All other specific embodiments obtained by those skilled in the art based on the specific embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0066] In order to further understand the content, features and effects of the present invention, the following specific embodiments are given as examples, and the attached Figure 1 -Attached Figure 3 The detailed instructions are as follows:

[0067] Example 1:

[0068] A continuous wind tunnel model elastic deformation testing system includes a first image acquisition device 1, a second image acquisition device 2, a first air-cooled pressure stabilizing cabin 3, a second air-cooled pressure stabilizing cabin 4, a first connecting block 5, a second connecting block 6 and a light source 7;

[0069] The first image acquisition device 1 is fixed in the first air-cooled pressure-stabilizing cabin 3 via a first fixing block 5, and the second image acquisition device 2 is fixed in the second air-cooled pressure-stabilizing cabin 4 via a second fixing block 6. A plurality of light sources 7 are mounted on the side walls of the wind tunnel test section 9; the first air-cooled pressure-stabilizing cabin 3 and the second air-cooled pressure-stabilizing cabin 4 are fixedly mounted on the upper surface of the wind tunnel test section 9;

[0070] Before the elastic deformation test of the continuous wind tunnel model, the wind tunnel shaft system calibration device is placed in the wind tunnel test section 9 to perform wind tunnel shaft system calibration, and then the wind tunnel shaft system calibration device is replaced with the model to be tested 8 to perform the elastic deformation test of the continuous wind tunnel model;

[0071] The wind tunnel shaft system calibration device includes a support rod 10, a first angle measuring instrument 11, a second angle measuring instrument 12, a checkerboard calibration plate 13 and a table 14. The checkerboard calibration plate 13 is embedded in the table 14. The first angle measuring instrument 11 and the second angle measuring instrument 12 are placed on the table 14 in the horizontal direction and the vertical direction respectively. The support rod 10 is installed on the side surface of the table 14. The wind tunnel shaft system calibration device is moved to multiple positions of the model 8 to be tested during the wind tunnel test through the support rod 10.

[0072] Furthermore, the table 14 of the wind tunnel shaft calibration device is connected to the support rod 10 through a flange.

[0073] Furthermore, the first image acquisition device 1 includes a camera and a lens, and the second image acquisition device 2 includes a camera and a lens. When the brightness of the marked point excites a light source of a specific band, an optical filter that selectively transmits the excitation band and effectively filters out light of other bands is configured in front of the lens.

[0074] Furthermore, if the first image acquisition device 1 and the second image acquisition device 2 need to identify specific wavelength excitation mark points, the image acquisition device also needs to install a specific optical filter in front of the lens to only allow the excitation light source to pass through and filter out other ambient light sources. If only regular mark points are to be identified, there is no need to install a filter in front of the lens.

[0075] Furthermore, the air-cooled pressure chamber is used to maintain a constant internal pressure during continuous wind tunnel vacuuming and negative pressure pressurization. Air inlets and outlets ensure air flow, ensuring that the image acquisition equipment can operate at normal temperature and pressure and dissipate heat properly. The air-cooled pressure chamber is fixed to the wind tunnel test section by welding or bolting.

[0076] Furthermore, the checkerboard calibration plate is precisely designed to be absolutely horizontal to ensure the accuracy of the calibration process. Two high-precision angle measuring instruments can be placed above the table to accurately measure the angle changes of the calibration plate.

[0077] Example 2:

[0078] A method for correcting elastic effects of a continuous wind tunnel model is implemented based on an elastic deformation testing system for a continuous wind tunnel model according to Example 1, and includes the following steps:

[0079] S1. Arrange a continuous wind tunnel model elastic deformation testing system;

[0080] S2. Calibrate the elastic deformation test system of a continuous wind tunnel model using a wind tunnel axis calibration device, including calibration of camera parameters and wind tunnel axis calibration;

[0081] Furthermore, the specific implementation method of step S2 includes the following steps:

[0082] S2.1. By adjusting the support rods, the table is placed at various positions of the model under test during the wind tunnel test. Images of the checkerboard calibration plate are captured using the first and second image acquisition devices. The camera's intrinsic and extrinsic parameters are calculated using the Zhang calibration method.

[0083] Furthermore, the camera parameter calibration is as follows: the intrinsic parameters are ; External parameters are ;in is the focal length in the u and v directions, is the radial distortion parameter, are the coordinates of the principal point; R and t are the rotation matrix and translation vector from the world coordinate system to the camera coordinate system, respectively.

[0084] The purpose of wind tunnel axis calibration is to obtain the transformation matrix from the camera coordinate system to the wind tunnel axis system: specifically, by adjusting the angle of the wind tunnel mechanism support, collecting the calibration plate at different pitch angles Based on the corner detection, the image coordinates of the corner points of the calibration plate images collected by the image acquisition devices I and II can be obtained by taking the image of the binocular camera. and external reference The three-dimensional coordinates of the corner points of the checkerboard calibration plate at different pitch angles can be obtained , m = 10. The rotation relationship between the three-dimensional coordinates of two adjacent pitch angle chessboard corner points is calculated by the Genro Kabsch algorithm , the rotation relationship is converted into an axis vector through the Rodrigues transformation , average it to get the pitch axis vector of the model in the wind tunnel axis system, normalize it so that the vector modulus is 1, and get the final pitch axis vector Similarly, we can get the yaw axis vector , based on the pitch axis vector They must be orthogonal, and the roll axis vector is obtained ;

[0085] S2.2. Wind tunnel axis calibration: By adjusting the angle of the wind tunnel mechanism support rod, the first image acquisition device and the second image acquisition device are used to collect images of the calibration plate at different pitch angles. The image coordinates of the corner points of the calibration plate images are obtained based on the corner point detection. and external reference The three-dimensional coordinates of the corner points of the checkerboard calibration plate at different pitch angles are obtained. The rotation relationship between the three-dimensional coordinates of the corner points of the two adjacent pitch angle checkerboards is calculated by the Genro-Kabsch algorithm. The rotation relationship is converted into an axis vector by the Rodrigues transformation. The average is obtained to obtain the pitch axis vector of the model to be tested in the wind tunnel axis system. The vector modulus is normalized to 1 to obtain the final pitch axis vector. ; Then calculate the yaw axis vector , roll axis vector ; Get the wind tunnel axis transformation matrix of the camera coordinate system , the expression is:

[0086] .

[0087] S3. Arrange markers on the model to be tested, arrange markers on the fuselage of the model to be tested for posture recognition, and arrange markers on the wing portion of the model to be tested for identifying elastic deformation of the wing;

[0088] Furthermore, the specific implementation method of step S3 includes the following steps:

[0089] S3.1. Arrange markers on the fuselage of the model to be tested, using an irregular distribution strategy to prevent multiple markers from falling on the same epipolar line. This ensures that marker matching can be effectively achieved under epipolar constraints from different viewing angles.

[0090] S3.2. Place markers on the wing of the model to be tested. Use a regular distribution strategy to place markers at the wing root, leading edge, and trailing edge. Ensure that the markers are evenly distributed in the spanwise and chordwise directions to identify the elastic deformation of the wing.

[0091] S4 uses the first image acquisition device, the second image acquisition device to acquire images, collect the reference image and test image of the model to be tested;

[0092] Furthermore, the specific implementation method of step S4 includes the following steps:

[0093] S4.1. Collect baseline images of the model to be tested: Collect image sequences of all working conditions in the absence of wind, and image sequences collected by the first image acquisition device in the absence of wind , Image sequence captured by the second image acquisition device when there is no wind , where m is the number of working conditions, is the image captured by the first image acquisition device in the mth working condition when there is no wind, The image captured by the second image acquisition device in the mth working condition when there is no wind, and the posture information sequence when there is no wind is recorded and the image captured by the first image acquisition device when the posture of the model to be tested is 0 in the absence of wind , the image captured by the second image acquisition device ,in is the attitude information of the mth working condition when there is no wind;

[0094] S4.2. Collect test images of the model to be tested: Collect image sequences of all working conditions during the test. The image sequence collected by the first image acquisition device during the test is , the image sequence captured by the second image acquisition device during the test , n is the number of working conditions during the test, and the posture information sequence during the test is recorded , set m greater than or equal to n, where is the image captured by the first image acquisition device of the nth working condition during the test, is the image captured by the second image acquisition device of the nth working condition during the test, is the posture information of the nth working condition during the test.

[0095] S5. Marker point recognition and matching of the reference image and test image of the model to be tested collected in step S4;

[0096] Furthermore, the specific implementation method of step S5 includes the following steps:

[0097] S5.1. Identify and match the same-name markers in the image captured by the first image acquisition device and the second image acquisition device, including fuselage marker matching and wing marker matching;

[0098] S5.1.1. The fuselage markers are matched using epipolar constraints to obtain a sequence of matching fuselage markers in the absence of wind. , where k is the number of marking points on the fuselage, is the image coordinate of the kth marker point on the fuselage in the image captured by the first image acquisition device, is the image coordinates of the kth marking point on the fuselage in the image captured by the second image acquisition device;

[0099] Furthermore, the epipolar constraint is specifically to assume that a point p in the space is in the image of camera 1 and camera 2 image The projection point on and , the projection equations of the two cameras in the system are: 、 , is the three-dimensional coordinate of point p in space, is the proportionality coefficient, is the rotation matrix, is the translation matrix, eliminating the scale factor can get the polar constraint equation and ,in , for the reason The antisymmetric matrix defined is, Known In the image The position within the image Inside The corresponding point must be located in the image On the inner polar line. Must be in a straight line Based on the epipolar constraint relationship, the initial candidate matching relationship is established and a symmetry test is performed. Matches that do not meet the constraint relationship in only one direction or both directions are considered false matches.

[0100] S5.1.2. Wing marker point matching is mainly performed through image correlation to obtain the matching wing marker point sequence in the absence of wind. , where l is the number of marking points on the wing, is the image coordinate of the lth marking point on the wing in the image captured by the first image acquisition device, The image coordinates of the lth marking point on the wing in the image captured by the second image acquisition device;

[0101] Furthermore, image correlation is specifically as follows: selection of registration feature points. For a single wing, 6 points are preferably selected, and an endpoint of the wing leading edge close to the fuselage is found along the span direction. , find an endpoint of the wing trailing edge close to the wing tip along the span direction , find a point near the middle along the leading edge , find a point near the middle along the trailing edge , find the farthest point of the wingspan , select a point in the middle area of ​​the wing surface , as a supplement to the local deformation. Based on this, we can get 6 feature points that characterize the wing layout from the perspective of camera 1 , 6 feature points representing the wing layout from the perspective of camera 2 .

[0102] Based on the thin plate spline deformation and the registration feature points obtained in a, the affine transformation relationship from the camera 2 perspective image to the camera 1 perspective image is constructed, that is, , mapping function The general form is = ,A is The affine transformation matrix is ​​used to describe the global linear change. is the weight of the control point, which describes the strength of the local distortion. Is the basis function, representing the point x to the control point The contribution of the distance to the distortion, the preferred tail radial basis function is = , = , in solving When input and , by minimizing the error function , solve A and , express the distortion mapping function as a matrix equation, and finally get = , where K is the radial basis function, is the regularization parameter used to control the smoothness of the distortion. After solving the equation, we get A and and b, and then we get .

[0103] Based on T and Get the coordinates of the same-named points of the camera 2 image captured by the camera 1. = ,at this time The location is very close , so image correlation can be used ,right and Match and complete and Get the matching sequence of wing marker points when there is no wind , where k is the number of marking points on the fuselage;

[0104] S5.1.3. Combining the camera internal and external parameters obtained in step S2 , through triangulation, reconstruct the 3D coordinates of the fuselage marker points matched in no wind The three-dimensional coordinates of the wing marker points matched with the no-wind ;

[0105] S5.1.4. Wind tunnel axis transformation matrix obtained in S2 , get the three-dimensional coordinate sequence of the fuselage in the wind tunnel coordinate system when there is no wind And the three-dimensional coordinate sequence of the wing marker point in the wind tunnel coordinate system when there is no wind ;

[0106] = , = ;

[0107] in, is the three-dimensional coordinate of the mark point on the fuselage of the mth working condition in the wind tunnel coordinate system when there is no wind, is the three-dimensional coordinate of the marked point on the wing of the mth working condition fuselage in the wind tunnel coordinate system when there is no wind;

[0108] Furthermore, the three-dimensional coordinates of the fuselage and wing markers in the wind tunnel coordinate system under the model 0 attitude can be obtained by the same logic: 、 , the three-dimensional coordinate sequence of the fuselage and the aircraft marker points in the wind tunnel coordinate system can be obtained during the test 、 .

[0109] S5.2. Perform matching of marker points under all working conditions and marker points when the posture is 0 in the image captured by the first image acquisition device and the second image acquisition device, including fuselage marker point matching and wing marker point matching;

[0110] S5.2.1. The fuselage markers are matched using a 3D point cloud matching method based on distance matching and singular value decomposition. The matching result sequence of the markers under any test condition on the fuselage and the markers when the posture is zero is obtained. , the expression is:

[0111] ;

[0112] in, is the three-dimensional coordinate of the mark point on the fuselage in the wind tunnel coordinate system when the attitude of the model to be tested is 0 in the absence of wind. is the three-dimensional coordinate of the mark point on the fuselage of the model to be tested in the wind tunnel coordinate system under the nth working condition during the test. and All the marking points in are one-to-one corresponding;

[0113] Furthermore, the optimal matching method of 3D point cloud based on distance matching and singular value decomposition is as follows:

[0114] for Any point in , calculate it to The distance between all points , t is The number of midpoints. Any point in Calculate it to The distance between all points , s is The number of midpoints. , according to and To calculate the matching point pairs. That is, there is , , , is the distance deviation threshold, preferably , then the current and It is a temporary matching point and retains the current matching result.

[0115] Repeat the above steps until all and All points in the , get multiple sets of matching results = . is the number of matching results.

[0116] For any matching point that meets the conditions, the optimal rotation matrix R and translation vector T are calculated by singular value decomposition (SVD), so that The matching point cloud in The point cloud in is optimally aligned. And the error between the transformed point cloud and the target point cloud is calculated ,if , then it is considered that the current matching point is the correct matching point. is the reconstruction error threshold.

[0117] S5.2.2. The wing markers are matched in two dimensions based on image correlation and then converted to three-dimensional coordinates in the wind tunnel coordinate system. The matching sequence of the wing markers under any test condition and the markers at attitude 0, as well as the markers under the corresponding condition in no wind, is obtained. The expression is:

[0118] = ;

[0119] in, is the three-dimensional coordinate of the mark point on the wing in the wind tunnel coordinate system when the attitude of the model to be tested is 0 in the absence of wind, is the three-dimensional coordinate of the marked point on the wing of the model to be tested in the wind tunnel coordinate system under the nth working condition during the test, is the three-dimensional coordinate of the mark point on the fuselage of the model to be tested in the wind tunnel coordinate system under the nth working condition in the absence of wind and the test. 、 and All the markers in are in one-to-one correspondence.

[0120] S6. Calculate the deformation and current posture of the wing of the test model under different working conditions;

[0121] Furthermore, the specific implementation method of step S6 includes the following steps:

[0122] S6.1. For the hth load case, h , calculate the attitude of the wing of the model to be tested. Based on the rigid body assumption, the expression is:

[0123] ;

[0124] in, for and The rotation matrix of the transformation between for and The translation vector between the transformations;

[0125] Solve by calculating the generalized inverse matrix or by using singular value decomposition and , the expression is:

[0126] ;

[0127] ;

[0128] in, - They correspond to the elements of the 1st row and 1st column, the 2nd row and 1st column, the 3rd row and 1st column, the 1st row and 2nd column, the 2nd row and 2nd column, the 3rd row and 2nd column, the 1st row and 3rd column, the 2nd row and 3rd column, and the 3rd row and 3rd column of the rotation matrix respectively. - Represents the first, second, and third components of the translation vector;

[0129] Will Convert to pitch angle , yaw angle , roll angle , 、 、 ;

[0130] Then the posture sequence of all test conditions is obtained ;

[0131] S6.2. For the hth load case, h , calculate the deformation of the wing of the model to be tested;

[0132] for ,calculate arrive The rotation matrix and translation matrices , then the three-dimensional coordinates of the h-th working condition wing marker point aligned to the zero attitude without wind are + , the three-dimensional coordinates of the h-th working condition wing mark point during the test are + , then the deformation of the marked point in the model coordinate system is - ;

[0133] Then the wing deformation of all working conditions is obtained .

[0134] S7. Correct the effects of elastic deformation on the model under test.

[0135] Furthermore, the specific implementation method of step S7 includes the following steps:

[0136] S7.1. Aerodynamic calculation of the original rigid model: Use PointWise software to generate an unstructured hybrid mesh of the model to be tested before deformation. Import the mesh into the CFD solver. Input the attitude information of the model to be tested, set the incoming flow conditions, and solve the flow field to obtain the aerodynamic coefficients such as lift and drag of the model to be tested before deformation;

[0137] S7.2. Select interpolation points on the mesh surface of the model to be measured, based on , interpolate to obtain the deformed surface mesh of the model to be tested, and then use the mesh deformation program to automatically generate the deformed mesh of the model;

[0138] S7.3. Calculate the aerodynamic forces of the deformed model using a CFD solver to correct for the effects of elastic deformation. Compare the aerodynamic forces with those before deformation to determine the effect of elastic deformation on the aerodynamic forces.

[0139] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0140] Although the present application has been described above with reference to specific embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, as long as there are no structural conflicts, the various features of the embodiments disclosed herein may be combined with each other in any manner, and the omission of an exhaustive description of these combinations in this specification is solely for the sake of space and resource conservation. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

Claims

1. A method for correcting elastic effects of a continuous wind tunnel model, which is implemented by relying on an elastic deformation test system of a continuous wind tunnel model, comprising a first image acquisition device (1), a second image acquisition device (2), a first air-cooled pressure stabilizing cabin (3), a second air-cooled pressure stabilizing cabin (4), a first fixed block (5), a second fixed block (6) and a light source (7); The first image acquisition device (1) is fixed in the first air-cooled pressure-stabilizing cabin (3) via a first fixed block (5), the second image acquisition device (2) is fixed in the second air-cooled pressure-stabilizing cabin (4) via a second fixed block (6), and a plurality of light sources (7) are mounted on the side wall of the wind tunnel test section (9); the first air-cooled pressure-stabilizing cabin (3) and the second air-cooled pressure-stabilizing cabin (4) are fixedly mounted on the upper surface of the wind tunnel test section (9); Before the elastic deformation test of the continuous wind tunnel model, the wind tunnel shaft system calibration device is placed in the wind tunnel test section (9) to calibrate the wind tunnel shaft system, and then the wind tunnel shaft system calibration device is replaced with the model to be tested (8) to perform the elastic deformation test of the continuous wind tunnel model; The wind tunnel shaft system calibration device comprises a support rod (10), a first angle measuring instrument (11), a second angle measuring instrument (12), a checkerboard calibration plate (13) and a table (14); the checkerboard calibration plate (13) is embedded in the table (14); the first angle measuring instrument (11) and the second angle measuring instrument (12) are respectively placed on the table (14) in the horizontal direction and the vertical direction; the side surface of the table (14) is installed with a support rod (10); the wind tunnel shaft system calibration device is moved to multiple positions of the model to be tested (8) during the wind tunnel test through the support rod (10); It is characterized by: The steps include: S1. Arrangement of a continuous wind tunnel model elastic deformation test system; S2. Calibrate the elastic deformation test system of a continuous wind tunnel model using a wind tunnel axis calibration device, including calibration of camera parameters and wind tunnel axis calibration; S3. Arrange markers on the model to be tested, arrange markers on the fuselage of the model to be tested for posture recognition, and arrange markers on the wing portion of the model to be tested for identifying elastic deformation of the wing; S4 uses the first image acquisition device, the second image acquisition device to acquire images, collect the reference image and test image of the model to be tested; The specific implementation method of step S4 includes the following steps: S4.

1. Collect baseline images of the model to be tested: Collect image sequences of all working conditions in the absence of wind, and image sequences collected by the first image acquisition device in the absence of wind , Image sequence captured by the second image acquisition device when there is no wind , where m is the number of working conditions, is the image captured by the first image acquisition device in the mth working condition when there is no wind, The image captured by the second image acquisition device in the mth working condition when there is no wind, and the posture information sequence when there is no wind is recorded and the image captured by the first image acquisition device when the posture of the model to be tested is 0 in the absence of wind , the image captured by the second image acquisition device ,in is the attitude information of the mth working condition when there is no wind; S4.

2. Collect test images of the model to be tested: Collect image sequences of all working conditions during the test. The image sequence collected by the first image acquisition device during the test is , the image sequence captured by the second image acquisition device during the test , n is the number of working conditions during the test, and the posture information sequence during the test is recorded , set m greater than or equal to n, where is the image captured by the first image acquisition device of the nth working condition during the test, is the image captured by the second image acquisition device of the nth working condition during the test, is the posture information of the nth working condition during the test; S5. Marker point recognition and matching of the reference image and test image of the model to be tested collected in step S4; S6. Calculate the deformation and current posture of the wing of the test model under different working conditions; S7. Correct the effects of elastic deformation on the model under test.

2. The elastic effect correction method for a continuous wind tunnel model according to claim 1, characterized in that: The specific implementation method of step S2 includes the following steps: S2.

1. By adjusting the support rods, the table is placed at various positions of the model under test during the wind tunnel test. Images of the checkerboard calibration plate are captured using the first and second image acquisition devices. The camera's intrinsic and extrinsic parameters are calculated using the Zhang calibration method. S2.

2. Wind tunnel axis calibration: By adjusting the angle of the wind tunnel mechanism support rod, the first image acquisition device and the second image acquisition device are used to collect images of the calibration plate at different pitch angles. The image coordinates of the corner points of the calibration plate images are obtained based on the corner point detection. and external reference The three-dimensional coordinates of the corner points of the checkerboard calibration plate at different pitch angles are obtained. The rotation relationship between the three-dimensional coordinates of the corner points of the two adjacent pitch angle checkerboards is calculated by the Genro-Kabsch algorithm. The rotation relationship is converted into an axis vector by the Rodrigues transformation. The average is obtained to obtain the pitch axis vector of the model to be tested in the wind tunnel axis system. The vector modulus is normalized to 1 to obtain the final pitch axis vector. ; Then calculate the yaw axis vector , roll axis vector ; Get the wind tunnel axis transformation matrix of the camera coordinate system , the expression is: 。 3. The elastic effect correction method for a continuous wind tunnel model according to claim 2, characterized in that: The specific implementation method of step S3 includes the following steps: S3.

1. Arrange markers on the fuselage of the model to be tested, using an irregular distribution strategy to prevent multiple markers from falling on the same epipolar line. This ensures that marker matching can be effectively achieved under epipolar constraints from different viewing angles. S3.

2. Place markers on the wing of the model to be tested. Use a regular distribution strategy to place markers at the root, leading edge, and trailing edge of the wing. Ensure that the markers are evenly distributed in the spanwise and chordwise directions to identify the elastic deformation of the wing.

4. The elastic effect correction method for a continuous wind tunnel model according to claim 3, characterized in that: The specific implementation method of step S5 includes the following steps: S5.

1. Identify and match the same-name markers in the image captured by the first image acquisition device and the second image acquisition device, including fuselage marker matching and wing marker matching; S5.1.

1. The fuselage markers are matched using epipolar constraints to obtain a sequence of matching fuselage markers in the absence of wind. , where k is the number of marking points on the fuselage, is the image coordinate of the kth marker point on the fuselage in the image captured by the first image acquisition device, is the image coordinates of the kth marking point on the fuselage in the image captured by the second image acquisition device; S5.1.

2. Wing marker point matching is mainly performed through image correlation to obtain the matching wing marker point sequence in the absence of wind. , where l is the number of marking points on the wing, is the image coordinate of the lth marking point on the wing in the image captured by the first image acquisition device, The image coordinates of the lth marking point on the wing in the image captured by the second image acquisition device; S5.1.

3. Combining the camera internal and external parameters obtained in step S2 , through triangulation, reconstruct the 3D coordinates of the fuselage marker points matched in no wind The three-dimensional coordinates of the wing marker points matched with the no-wind ; S5.1.

4. Wind tunnel axis transformation matrix obtained in S2 , get the three-dimensional coordinate sequence of the fuselage in the wind tunnel coordinate system when there is no wind And the three-dimensional coordinate sequence of the wing marker point in the wind tunnel coordinate system when there is no wind ; = ， = ； in, is the three-dimensional coordinate of the mark point on the fuselage of the mth working condition in the wind tunnel coordinate system when there is no wind, is the three-dimensional coordinate of the marked point on the wing of the mth working condition fuselage in the wind tunnel coordinate system when there is no wind; S5.

2. Perform matching of marker points under all working conditions and marker points when the posture is 0 in the image captured by the first image acquisition device and the second image acquisition device, including fuselage marker point matching and wing marker point matching; S5.2.

1. The fuselage markers are matched using a 3D point cloud matching method based on distance matching and singular value decomposition. The matching result sequence of the markers under any test condition on the fuselage and the markers when the posture is zero is obtained. , the expression is: ； in, is the three-dimensional coordinate of the mark point on the fuselage in the wind tunnel coordinate system when the attitude of the model to be tested is 0 in the absence of wind. is the three-dimensional coordinate of the mark point on the fuselage of the model to be tested in the wind tunnel coordinate system under the nth working condition during the test. and All the marking points in are one-to-one corresponding; S5.2.

2. The wing markers are matched in two dimensions based on image correlation and then converted to three-dimensional coordinates in the wind tunnel coordinate system. The matching sequence of the wing markers under any test condition and the markers at attitude 0, as well as the markers under the corresponding condition in no wind, is obtained. The expression is: = ； in, is the three-dimensional coordinate of the mark point on the wing in the wind tunnel coordinate system when the attitude of the model to be tested is 0 in the absence of wind, is the three-dimensional coordinate of the marked point on the wing of the model to be tested in the wind tunnel coordinate system under the nth working condition during the test, is the three-dimensional coordinate of the mark point on the fuselage of the model to be tested in the wind tunnel coordinate system under the nth working condition in the absence of wind and the test. 、 and All the markers in are in one-to-one correspondence.

5. The elastic effect correction method for a continuous wind tunnel model according to claim 4, characterized in that: The specific implementation method of step S6 includes the following steps: S6.

1. For the hth load case, h , calculate the attitude of the wing of the model to be tested. Based on the rigid body assumption, the expression is: ； in, for and The rotation matrix of the transformation between for and The translation vector between the transformations; Solve by calculating the generalized inverse matrix or by using singular value decomposition and , the expression is: ； ； in, - They correspond to the elements of the 1st row and 1st column, the 2nd row and 1st column, the 3rd row and 1st column, the 1st row and 2nd column, the 2nd row and 2nd column, the 3rd row and 2nd column, the 1st row and 3rd column, the 2nd row and 3rd column, and the 3rd row and 3rd column of the rotation matrix respectively. - Represents the first, second, and third components of the translation vector; Will , 、 、 ; Then the posture sequence of all test conditions is obtained ; S6.

2. For the hth load case, h , calculate the deformation of the wing of the model to be tested; for ,calculate arrive The rotation matrix and translation matrices , then the three-dimensional coordinates of the h-th working condition wing marker point aligned to the zero attitude without wind are + , the three-dimensional coordinates of the h-th working condition wing mark point during the test are + , then the deformation of the marked point in the model coordinate system is - ; Then the wing deformation of all working conditions is obtained .

6. The elastic effect correction method for a continuous wind tunnel model according to claim 5, characterized in that: The specific implementation method of step S7 includes the following steps: S7.

1. Aerodynamic calculation of the original rigid model: Use PointWise software to generate an unstructured hybrid mesh of the model to be tested before deformation. Import the mesh into the CFD solver. Input the attitude information of the model to be tested, set the incoming flow conditions, and solve the flow field to obtain the aerodynamic coefficients such as lift and drag of the model to be tested before deformation; S7.

2. Select interpolation points on the mesh surface of the model to be measured, based on , interpolate to obtain the deformed surface mesh of the model to be tested, and then use the mesh deformation program to automatically generate the deformed mesh of the model; S7.

3. Calculate the aerodynamic forces of the deformed model using a CFD solver to correct for the effects of elastic deformation. Compare the calculated aerodynamic forces with those before deformation to determine the effect of elastic deformation on the aerodynamic forces.

7. The elastic effect correction method for a continuous wind tunnel model according to claim 6, characterized in that: The table (14) of the wind tunnel shaft system calibration device is connected to the support rod (10) through a flange.

8. The elastic effect correction method for a continuous wind tunnel model according to claim 7, characterized in that: The first image acquisition device (1) includes a camera and a lens, and the second image acquisition device (2) includes a camera and a lens. When the brightness of the marking point excites a light source of a specific wavelength band, an optical filter that selectively transmits the excitation wavelength band and effectively filters out light of other wavelength bands is arranged in front of the lens.

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