A sidewall balance system and method for measuring bionic flexible skin wings

Abstract

A sidewall balance system and method for measuring bionic flexible skin wings belong to the field of aerodynamic wind tunnel test technology, and are intended to comprehensively and effectively identify the aerodynamic performance gain effect of bionic flexible skin lift-increasing and drag-reducing wings. The sidewall balance system includes a sidewall balance, which is installed in the side wall of the test section. The sidewall balance includes a floating plate and a fixed plate. The floating plate and the fixed plate are connected by three lateral force units, two longitudinal force units and one transverse force unit. Each force measuring unit includes a tension-compression balance, and the model under test is connected to the floating plate through a low heat flux insulation flange. The present invention proposes an assembled sidewall balance system of tension-compression balances. Compared with the cantilever beam sidewall balance, the present invention has an improved overall stiffness and greatly reduced interference between components. Combined with the original measurement method, the various element forces and moments of the bionic flexible skin wing wind tunnel test can be accurately obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of aerodynamic wind tunnel testing, and in particular relates to a sidewall balance system and method for measuring a bionic flexible skin wing. Background Art

[0002] Bionic flexible skin lift-and-drag wings can effectively increase lift while reducing drag, and are currently a hot topic in aerospace research. Wind tunnel testing is an effective method to determine the aerodynamic characteristics of flexible skin lift-and-drag wings and compare the drag reduction effect of flexible structures with those of non-flexible structures.

[0003] The wind tunnel test of the skinned lift-reduced wing is a component force test. Current wind tunnel tests use sidewall balances for measurement. Considering the small lateral aerodynamic loads on sidewall-mounted models, the balances are typically five-component. Existing sidewall balances typically use a five-component, monolithic structure with a traditional single-section or multi-section column beam / sheet beam structure. This presents the following main problems:

[0004] (1) Low rigidity. This type of balance uses a cantilever beam structure with large deformation. In addition, in order to meet the needs of mechanical decomposition, multiple measuring sections may be set, further reducing the rigidity.

[0005] (2) Incomplete decoupling. Single-section or multi-section column beam / sheet beam structures do not have interference cancellation structures, resulting in a large interference output from other components on the component to be measured. Incomplete decoupling leads to low accuracy of the sidewall balance, and the ability to distinguish small gains in the aerodynamic characteristics of flexible skin lift-reducing and drag-reducing wings is limited.

[0006] (3) Incomplete measurement dimensions. This type of balance generally has five components. Adding a sixth component will increase the cost and also cause the overall measurement performance to decrease due to the increase in the measurement cross section.

[0007] (4) Large temperature effect. Due to the lack of effective heat insulation measures, the temperature effect of the balance is large, resulting in changes in the balance zero point and reduced measurement accuracy.

[0008] (5) Insufficient correction means. The current side wall balance lacks effective correction means. The influence of elastic angle, installation angle, and distance between two centers on the balance coordinate system conversion is not fully considered. At the same time, there is a lack of effective means to measure the above parameters.

[0009] These issues limit the measurement accuracy of biomimetic flexible skin wings, and there is an urgent need to find a six-component sidewall balance that can meet high stiffness requirements, high decoupling, low-temperature efficiency, and high precision. This will improve the accuracy of wind tunnel test data for skinned high-lift, low-rent wings. Summary of the Invention

[0010] To overcome the shortcomings of the prior art, the present invention proposes a sidewall balance and method for measuring biomimetic flexible skin lift-enhancing and drag-reducing wings, aiming to comprehensively and effectively identify the aerodynamic performance gains of biomimetic flexible skin lift-enhancing and drag-reducing wings. The technical solutions adopted by the present invention are as follows:

[0011] A sidewall balance system for measuring a bionic flexible skin wing includes a sidewall balance, a low heat flux insulation flange, and a model to be measured. The sidewall balance is installed in the sidewall of a test section and includes a floating plate, a fixed plate, a force measuring assembly, and a high-precision dual-axis angle sensor. The fixed plate and the floating plate are set to be coaxially arranged left and right. A balance coordinate system xyz is established on the sidewall balance. The z-axis of the balance coordinate system is set to coincide with the axes of the floating plate and the fixed plate, with the right direction being the positive direction. The y-axis of the balance coordinate system is set to be positive upward, and the x-axis of the balance coordinate system is set to be positive forward. The model to be measured is connected to the right side of the floating plate via the low heat flux insulation flange. The model to be measured is located in the incoming flow within the test section.

[0012] The model under test is a bionic flexible skin wing, a high-precision dual-axis angle sensor is arranged on a floating plate, and the force measuring assembly includes six force measuring units, which are divided into three lateral force units, two longitudinal force units and one transverse force unit. The lateral force units are arranged parallel to the z-axis, the lateral force unit arranged directly above the z-axis is marked as P1, the lateral force unit arranged below the rear of the z-axis is marked as P2, and the lateral force unit arranged below the front of the z-axis is marked as P3. P2 and P3 are symmetrical about the yz plane. The three lateral force units are arranged in an isosceles triangle, and the axes of the three lateral force units are equidistant from the z-axis. The transverse force unit is arranged along the x-axis, and the transverse force unit is marked as P6. The two longitudinal force units are arranged symmetrically about the yz plane, and the longitudinal force units are parallel to the y-axis. The longitudinal force unit arranged behind the z-axis is marked as P4, and the longitudinal force unit arranged in front of the z-axis is marked as P5. Both ends of the six force measuring units are respectively connected to the floating plate and the fixed plate.

[0013] Furthermore, the force measuring unit includes an expansion core, an expansion sleeve, a tension-compression balance, a longitudinal and transverse decoupling cross pivot and an end connecting flange. The expansion sleeve is sleeved on the expansion core, and the expansion core is connected to the tension-compression balance, the longitudinal and transverse decoupling cross pivot, the end connecting flange and the floating plate in sequence. Six connecting holes are opened on the fixed plate, and the outer periphery of the expansion sleeve is tightly connected to the inner periphery corresponding to the connecting holes.

[0014] Furthermore, the longitudinal and transverse decoupling cross pivot includes a set of weakened openings arranged laterally with a span of 100mm to 150mm and a set of weakened openings arranged longitudinally with a span of 100mm to 150mm, and the width of the weakened openings is 0.5mm to 2mm.

[0015] Furthermore, a preload washer is provided between the tension-compression balance and the longitudinal and transverse decoupling cross pivot, and the preload force of the preload washer is greater than or equal to 120% of the measuring range of the tension-compression balance.

[0016] Furthermore, the labyrinth seal and the boundary layer plate are sequentially sleeved on the low heat flux insulation flange from the inside to the outside, and a labyrinth flow channel is formed between the labyrinth seal and the boundary layer plate.

[0017] Furthermore, the low heat flux insulation flange is a necked flange, and a plurality of L-shaped slit structures are provided on the flange neck of the low heat flux insulation flange, and the total length of the plurality of slit structures in the circumferential direction is greater than or equal to one quarter of the circumference of the flange neck.

[0018] Furthermore, a low thermal conductivity insulation gasket is provided between the low heat flux insulation flange and the side wall balance.

[0019] The present invention also provides a method for measuring a bionic flexible skin wing, which is implemented based on the above-mentioned sidewall balance system for measuring a bionic flexible skin wing and includes the following steps:

[0020] Step 1: There are several tension and compression balances. Select the appropriate one according to the force measurement range of the wind tunnel test.

[0021] Step 2: Perform single-component calibration on each tension and compression balance to obtain the linear relationship between the calculated load value and the output voltage increment of the tension and compression balance:

[0022] ... (1);

[0023] Where:

[0024] is the calculated load value of the nth tension-compression balance, where n is an integer from 1 to 6;

[0025] is the intercept term;

[0026] is the principal coefficient of the nth tension-compression balance;

[0027] is the voltage increment generated by the nth tension-compression balance under load;

[0028] Step 3: Make a positioning tool. The floating plate and the fixed plate are both provided with three stepped holes. The stepped holes on the floating plate and the fixed plate are coaxially aligned one by one. The positioning tool includes a locking screw, an annular positioning sleeve and a positioning pin. One end of the positioning pin is provided with a shoulder. The shoulder of the positioning pin cooperates with the stepped hole stop of the floating plate and is connected by a screw. The annular positioning sleeve is sleeved on the other end of the positioning pin. The outer periphery of the annular positioning sleeve cooperates with the corresponding stepped hole of the fixed plate and is tightened and fixed by the locking screw to achieve the initial fixation of the floating plate and the fixed plate.

[0029] Step 4: Install the sidewall balance on the calibration table. After the sidewall balance is working properly, remove the annular positioning sleeve and loosen the locking screw to leave a gap between the locking screw and the fixed plate.

[0030] Step 5: Connect the low heat flux insulation flange and adjust the roll and pitch angles of the sidewall balance using the calibration table so that the high-precision dual-axis angle sensor reads 0±0.05°. Mark the current state of the sidewall balance as the calibration reference state and record the calibration reference voltage Ui of the tension and compression balance in the calibration reference state.

[0031] Step 6: Collect the voltage values ​​of the tension and compression balances at the side wall balance at 0° roll angle, 90° roll angle, 180° roll angle, and 270° roll angle to obtain the absolute natural zero point of the tension and compression balance , The calculation formula is:

[0032] ;

[0033] Step 7: Calculate the voltage difference between the calibration reference state and the absolute natural zero point :

[0034] ... (2);

[0035] According to formula (1) and formula (2), the load value P of the tension and compression balance under the calibration reference state is calculated: n0 , n is an integer from 1 to 6;

[0036] Step 8: P n0 As a reference, balance the side wall so that P n0 Within ±20% FS, and record P n0 Numeric value;

[0037] Step 9: Perform joint calibration on the side wall balance to balance the P n0 The value is zero point, and a joint calibration load table is prepared according to the range. The load table format is as follows:

[0038] ;

[0039] The corresponding load values ​​of the tension and compression balance are as follows:

[0040] ;

[0041] Step 10: Perform bridge calculation on the matrix column vector of the tension and compression balance load values ​​in step 9. The measured load values ​​of the tension and compression balance after bridge assembly are:

[0042] ;

[0043] Step 11: Using the applied load matrix as the independent variable and the measured load value of the tension and compression balance after the bridge is assembled as the dependent variable, the implicit second-order relationship between the applied load and the load increment of each tension and compression balance is obtained by the least squares method. The balance formula is:

[0044] ;

[0045] Where:

[0046] is the calculated load value of the nth component of the sidewall balance, where n is an integer from 1 to 6;

[0047] is the load measurement value of the tension and compression balance after loading the bridge of the nth component group of the side wall balance;

[0048] is the intercept term of the nth component;

[0049] is the principal term coefficient of the nth component of the side wall balance;

[0050] is the one-time interference coefficient of the jth component on the nth component of the loaded sidewall balance;

[0051] is the square interference coefficient of the jth component of the loaded side wall balance on the nth component;

[0052] is the cross-interference coefficient of the j-th component and the k-th component on the n-th component of the loaded side wall balance;

[0053] Step 12: Connect the model under test to the low-flux thermal insulation flange 2, place the model under test in the test section, level the model under test, and mount weights on the loading hole of the model's torque reference point. After loading, reset the mechanism and obtain the relative measured load values ​​of the side wall balance at 0° roll angle, 90° roll angle, 180° roll angle, and 270° roll angle. Calculate the installation angle and the distance between the two centers according to the following six formulas:

[0054] ;

[0055] ;

[0056] ;

[0057] ;

[0058] ;

[0059] ;

[0060] Where:

[0061] is the installation angle of the model under test in the pitch direction relative to the side wall balance;

[0062] is the yaw installation angle of the model under test relative to the sidewall balance;

[0063] The installation angle of the model under test in the roll direction relative to the sidewall balance;

[0064] The axial force measured by the side wall balance after loading the weight at a roll angle of 0°;

[0065] The axial force load value of the side wall balance after loading the weight at a 90° roll angle;

[0066] The axial force measured by the side wall balance after loading the weight at a roll angle of 180°;

[0067] The axial force measured by the side wall balance after loading the weight at a roll angle of 270°;

[0068] is the normal force measured on the side wall balance after loading the weight at a roll angle of 0°;

[0069] The normal force measured on the side wall balance after loading the weight at a 90° roll angle;

[0070] The normal force measured on the side wall balance after the weight is loaded at a roll angle of 180°;

[0071] The normal force measured on the side wall balance after loading the weight at a roll angle of 270°;

[0072] The lateral force measured by the side wall balance after loading the weight at a roll angle of 0°;

[0073] The measured value of the lateral force of the side wall balance after loading the weight at a 90° roll angle;

[0074] The lateral force measured by the side wall balance after loading the weight at a roll angle of 180°;

[0075] The lateral force measured by the side wall balance after loading the weight at a roll angle of 270°;

[0076] The rolling moment measurement value of the side wall balance after loading the weight at a roll angle of 0°;

[0077] The rolling moment measurement value of the side wall balance after loading the weight at a 90° rolling angle;

[0078] The rolling moment measurement value of the side wall balance after loading the weight at a rolling angle of 180°;

[0079] The rolling moment measurement value of the side wall balance after loading the weight at a rolling angle of 270°;

[0080] is the yaw moment measurement of the sidewall balance after loading the weight at a roll angle of 0°;

[0081] The yaw moment measured by the sidewall balance after loading the weight at a 90° roll angle;

[0082] The yaw moment measured by the sidewall balance after loading the weight at a roll angle of 180°;

[0083] The yaw moment measured by the sidewall balance after loading the weight at a roll angle of 270°;

[0084] is the measured value of the pitching moment of the side wall balance after the weight is loaded at a roll angle of 0°;

[0085] is the measured value of the pitching moment of the side wall balance after the weight is loaded at a roll angle of 90°;

[0086] The measured value of the pitching moment of the side wall balance after the weight is loaded at a roll angle of 180°;

[0087] The measured value of the pitching moment of the side wall balance after the weight is loaded at a roll angle of 270°;

[0088] is the distance between the calibration center and the torque reference point along the x-axis;

[0089] is the distance between the calibration center and the torque reference point along the y-axis;

[0090] is the distance between the calibration center and the torque reference point along the z-axis;

[0091] Step 13: Measure the elastic deformation angle of the side wall balance-low heat flux insulation flange under the action of longitudinal force, transverse force, longitudinal moment and transverse moment, obtain the angle change - balance measurement load data set, and use multivariate fitting to obtain the elastic angle correction formula:

[0092] ;

[0093] ;

[0094] ;

[0095] Where:

[0096] To measure the elastic angle of the side wall balance in the pitch direction;

[0097] To measure the yaw elastic angle of the sidewall balance;

[0098] To measure the elastic angle in the rolling direction of the sidewall balance;

[0099] Mz is the pitching moment of the sidewall balance;

[0100] X is the axial force of the side wall balance;

[0101] My is the yaw moment of the sidewall balance;

[0102] Y is the normal force of the side wall balance;

[0103] Mx is the rolling moment of the sidewall balance;

[0104] is the elastic angle correction coefficient of the pitching moment Mz;

[0105] is the elastic angle correction coefficient of the axial force X;

[0106] is the elastic angle correction coefficient of the yaw moment My;

[0107] is the elastic angle correction coefficient of the normal force Y;

[0108] is the elastic angle correction coefficient of the rolling moment Mx;

[0109] Step 14: Prepare for the wind tunnel test and measure the absolute natural zero point according to step 6;

[0110] Step 15: Measure the deadweight load F of the corresponding side wall balance according to the sequence of preset attitude angles θ off ;

[0111] Step 16: Perform a wind blowing test at a preset attitude angle θ;

[0112] Step 17: Calculate the load F on the side wall balance after blowing on Relative to deadweight load F off the increment;

[0113] Step 18: Calculate the load increment elastic angle generated after blowing according to the elastic angle correction formula obtained in step 13 ;

[0114] Step 19: Compare the preset attitude angle θ when there is no wind with the incremental elastic angle θ of the wind load obtained in step 18. e Add them together to obtain the corrected wind-blowing attitude angle, and calculate the wind-free deadweight load corresponding to the corrected attitude angle value by interpolation. , forming a modified deadweight load sequence;

[0115] Step 20: Repeat steps 17 to 19. off With the corrected no-wind deadweight load The iteration stops when the difference is less than or equal to 0.05% FS;

[0116] Step 21: Calculate the six-element loads Y, Mz, Mx, X, Z, and My in the balance coordinate system after deducting its own weight;

[0117] Step 22: Establish the model body axis coordinate system x1y1z1. The z1 axis of the model body axis coordinate system coincides with the z axis of the balance coordinate system, and the positive direction is the same. The origin of the model body axis coordinate system is located on the end face of the measured model close to the side wall balance. Ignore the resistance at the bottom of the measured model. Convert the six-element load in the balance coordinate system to the model body axis coordinate system. 、 and The order of magnitude is too small, so the effect of the rotation order on the coordinate transformation can be ignored. The rotation order is agreed to be zyx, and the transformation matrix from the balance coordinate system to the model body axis coordinate system is:

[0118] ;

[0119] Then the force and moment in the balance coordinate system are converted to the force and moment in the model body axis coordinate system:

[0120] ;

[0121] ;

[0122] in:

[0123] The force vector converted to the model axis system is positive along the positive direction of the coordinate axis;

[0124] To convert the moment vector into the model axis system, the positive direction around the coordinate axis is positive;

[0125] F is the force under the balance axis;

[0126] M is the moment under the balance axis;

[0127] is the roll angle under the balance axis system;

[0128] ;

[0129] ;

[0130] .

[0131] Compared with the prior art, the present invention has the following beneficial effects:

[0132] 1. This invention proposes an assembled sidewall balance system for tension and compression. Three lateral force units are arranged in an isosceles triangle to measure rolling moment Mx, yaw moment My, and lateral force Z. Two longitudinal force units are arranged in a tandem arrangement to measure normal force Y and pitching moment Mz. A transverse force unit, located on the horizontal center plane of the sidewall balance, measures axial force X. Compared to cantilever beam sidewall balances, this invention improves overall stiffness while significantly reducing inter-component interference. Combined with a unique measurement method, it can accurately obtain the individual forces and moments in wind tunnel tests of biomimetic flexible skin wings.

[0133] 2. The present invention uses a positioning tool to pre-install the side wall balance, which effectively ensures the accurate positioning and assembly of the side wall balance. The structure of the expansion sleeve and the expansion core is used to give axial freedom during installation. At the same time, combined with the radial low stiffness characteristics of the longitudinal and transverse decoupling cross pivot, it avoids the problem of over-constraint in the assembly of the side wall balance.

[0134] 3. The present invention proposes an overall calibration method for the side wall balance based on the load measurement value of the tension and compression balance, and obtains the second-order relationship balance formula between the side wall balance force and torque and each tension and compression balance force. After one overall calibration, subsequent replacement of tension and compression balances with different ranges or finished tension and compression sensors does not require overall calibration.

[0135] 4. The present invention innovatively proposes a method for calculating the measured model and the installation angle and the distance between the two centers of the balance based on the load of the tension and compression balance itself, which solves the technical problem that the side wall balance cannot obtain all the installation angles and the distance between the two centers, and breaks the limitation of low accuracy of measuring the installation angle and the distance between the two centers using a ruler in wind tunnel tests.

[0136] 5. The present invention innovatively proposes a deadweight iteration method based on elastic angle compensation, which improves the force and torque measurement accuracy. This method can be extended to full-mode force measurement tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0137] Figure 1 is a front cross-sectional view of the sidewall balance system of the present invention;

[0138] Figure 2 is a top cross-sectional view of the sidewall balance system of the present invention;

[0139] Figure 3 It is a right side view of the sidewall balance system of the present invention;

[0140] Figure 4 yes Figure 2 A magnified view of point A;

[0141] Figure 5 It is the main view of the longitudinal and transverse decoupling cross pivot;

[0142] Figure 6 It is a side view of the longitudinal and transverse decoupling cross pivot;

[0143] Figure 7 yes Figure 2 BB cross-sectional view;

[0144] Figure 8 It is the right view layout of the force measuring assembly;

[0145] Figure 9 It is the main view layout of the force measuring assembly;

[0146] Figure 10 is an axonometric view of the sidewall balance system of the present invention;

[0147] Figure 11 It is a flow chart of the method of the present invention.

[0148] Figure 1. Sidewall balance, 2. Low heat flux insulation flange, 3. Measured model, 4. Boundary plate, 5. Labyrinth seal, 6. Floating plate, 7. Fixed plate, 8. Force measuring assembly, 9. Positioning fixture, 10. High-precision dual-axis angle sensor, 11. Expansion core, 12. Expansion sleeve, 13. Tension-compression balance, 14. Preload washer, 15. Vertical and horizontal decoupling cross pivot, 16. End connection flange, 17. Low thermal conductivity insulation gasket, 18. Flange screw, 19. Locking screw, 20. Annular locating sleeve, 21. Locating pin, 22. Weakened opening, 23. Labyrinth flow channel, 24. Lateral force unit, 25. Longitudinal force unit, 26. Transverse force unit, 27. Slit structure. DETAILED DESCRIPTION

[0149] To make the objectives, technical solutions, and advantages of the present invention more clearly apparent, the present invention is described below using specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely illustrative and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0150] The connections mentioned in the present invention are divided into fixed connections and detachable connections. The fixed connection refers to a non-detachable connection, including but not limited to conventional fixed connection methods such as hem connection, rivet connection, adhesive connection, and welding connection. The detachable connection refers to but not limited to conventional detachable connection methods such as bolt connection, snap connection, pin connection, and hinge connection. When the specific connection method is not clearly specified, it is assumed that at least one connection method can be found among the existing connection methods to achieve the function. Those skilled in the art can choose according to their needs. For example, a welded connection is selected for a fixed connection, and a bolted connection is selected for a detachable connection.

[0151] The present invention will be further described in detail below with reference to the accompanying drawings. The following embodiments are provided to explain the present invention, but the present invention is not limited to the following embodiments.

[0152] Example 1: Figures 1 to 11 As shown, a sidewall balance system for measuring a bionic flexible skin wing includes a sidewall balance 1, a low heat flux insulation flange 2, and a model under test 3. The sidewall balance 1 is installed in the sidewall of the test section. The sidewall balance 1 includes a floating plate 6, a fixed plate 7, a force measuring assembly 8, and a high-precision dual-axis angle sensor 10. The fixed plate 7 and the floating plate 6 are set to be coaxially arranged left and right. A balance coordinate system xyz is established on the sidewall balance 1. The z-axis of the balance coordinate system is set to coincide with the axis of the floating plate 6 and the fixed plate 7, with the right direction being the positive direction. The y-axis of the balance coordinate system is set to be positive upward, and the x-axis of the balance coordinate system is set to be positive forward. The model under test 3 is connected to the right side of the floating plate 6 via the low heat flux insulation flange 2. The model under test 3 is in the incoming flow within the test section.

[0153] The measured model 3 is a bionic flexible skin wing, a high-precision dual-axis angle sensor 10 is arranged on the floating plate 6, and the force measuring assembly 8 includes six force measuring units, which are divided into three lateral force units 24, two longitudinal force units 25 and one lateral force unit 26. The lateral force units 24 are arranged parallel to the z-axis, and the lateral force unit 24 arranged just above the z-axis is marked as P1, the lateral force unit 24 arranged below the rear of the z-axis is marked as P2, and the lateral force unit 24 arranged below the front of the z-axis is marked as P3. P2 and P The three lateral force units 24 are arranged symmetrically about the yz plane in an isosceles triangle. The axes of the three lateral force units 24 are equidistant from the z axis. The transverse force unit 26 is arranged along the x axis and is labeled P6. The two longitudinal force units 25 are arranged symmetrically about the yz plane and are parallel to the y axis. The longitudinal force unit 25 arranged behind the z axis is labeled P4, and the longitudinal force unit 25 arranged in front of the z axis is labeled P5. Both ends of the six force measuring units are connected to the floating plate 6 and the fixed plate 7, respectively.

[0154] The present invention proposes an assembled sidewall balance system with a tension-compression balance 13. Three lateral force units 24 are arranged in an isosceles triangle, capable of measuring the rolling moment MxP2+P3-P1, the yaw moment MyP2-P3, and the lateral force ZP1+P2+P3. Two longitudinal force units 25 are arranged in a tandem configuration, measuring the normal force YP4+P5 and the pitching moment MzP4-P5. A transverse force unit 26, located on the horizontal center plane of the sidewall balance 1, measures the axial force XP1. Compared to a cantilever beam sidewall balance, the present invention improves overall stiffness while significantly reducing inter-component interference. Combined with a unique measurement method, the various forces and moments of wind tunnel tests on biomimetic flexible skin wings can be accurately obtained.

[0155] The force measuring unit comprises an expansion core 11, an expansion sleeve 12, a tension-compression balance 13, a longitudinal and transverse decoupling cross-pivot 15, and an end connection flange 16. The expansion sleeve 12 is fitted onto the expansion core 11, which in turn is connected to the tension-compression balance 13, the longitudinal and transverse decoupling cross-pivot 15, the end connection flange 16, and the floating plate 6. The fixed plate 7 is provided with six connection holes, and the outer periphery of the expansion sleeve 12 is tension-connected to the inner periphery of the corresponding connection holes. The longitudinal and transverse decoupling cross-pivot 15, combined with the assembled sidewall balance 1, increases overall rigidity while further reducing interference between components. The end connection flange 16 is secured to the floating plate 6 via flange screws 18.

[0156] The longitudinal and transverse decoupling cross pivot 15 includes a set of transversely arranged weakened openings 22 with a span of 100 mm to 150 mm and a set of longitudinally arranged weakened openings 22 with a span of 100 mm to 150 mm. The width of the weakened openings 22 is 0.5 mm to 2 mm.

[0157] A preload washer 14 is provided between the tension-compression balance 13 and the longitudinal and transverse decoupling cross pivot 15 , and the preload force of the preload washer 14 is greater than or equal to 120% of the measuring range of the tension-compression balance 13 .

[0158] The labyrinth seal 5 and the boundary layer plate 4 are sequentially sleeved on the low heat flux insulation flange 2 from the inside to the outside, and a labyrinth flow channel 23 is formed between the labyrinth seal 5 and the boundary layer plate 4 to prevent the airflow from directly entering the side wall balance 1.

[0159] The low-heat-flux insulation flange 2 is a necked flange with a plurality of L-shaped slotted structures 27 defined on its flange neck. The total circumferential length of the slotted structures 27 is greater than or equal to one-quarter of the flange neck circumference, effectively preventing heat transfer from the model under test 3 in the wind tunnel to the sidewall balance 1. The present invention innovatively proposes a low-heat-flux insulation flange 2 with L-shaped slotted structures 27, effectively reducing heat transfer from the model under test 3 to the sidewall balance 1. This structural form is also of great significance for thermal protection designs of other types of balances.

[0160] A low thermal conductivity insulation gasket 17 is provided between the low heat flux insulation flange 2 and the side wall balance 1 .

[0161] Example 2: Figures 1 to 11 As shown, a method for measuring a bionic flexible skin wing is implemented based on the sidewall balance system for measuring a bionic flexible skin wing described in Example 1, and includes the following steps:

[0162] Step 1: There are several tension and compression balances 13, and a suitable tension and compression balance 13 is selected according to the force measurement range of the wind tunnel test;

[0163] Step 2: Perform single-component calibration on each tension-compression balance 13 to obtain a linear relationship between the calculated load value of the tension-compression balance 13 and the increment of the output voltage value of the tension-compression balance 13:

[0164] ... (1);

[0165] Where:

[0166] is the calculated load value of the nth tension-compression balance 13, where n is an integer from 1 to 6;

[0167] is the intercept term;

[0168] is the principal term coefficient of the nth tension-compression balance 13;

[0169] is the voltage increment generated by the nth tension-compression balance 13 under the action of load;

[0170] Step 3: Make a positioning tool 9. Three stepped holes are provided on the floating plate 6 and the fixed plate 7. The stepped holes on the floating plate 6 and the fixed plate 7 are coaxially aligned one by one. The positioning tool 9 includes a locking screw 19, an annular positioning sleeve 20 and a positioning pin 21. One end of the positioning pin 21 is provided with a shoulder. The shoulder of the positioning pin 21 cooperates with the stepped hole stop of the floating plate 6 and is connected by a screw. The annular positioning sleeve 20 is sleeved on the other end of the positioning pin 21. The outer periphery of the annular positioning sleeve 20 cooperates with the stepped hole corresponding to the fixed plate 7 and is tightened and fixed by the locking screw 19 to achieve the initial fixation of the floating plate 6 and the fixed plate 7.

[0171] Step 4: Install the sidewall balance 1 on the calibration table. After the sidewall balance 1 works normally, remove the annular positioning sleeve 20 and loosen the locking screw 19 to leave a gap between the locking screw 19 and the fixed plate 7;

[0172] Step 5: Connect the low heat flux insulation flange 2, and adjust the roll angle and pitch angle of the sidewall balance 1 through the calibration table so that the reading of the high-precision dual-axis angle sensor 10 is 0±0.05°. Mark the state of the sidewall balance 1 at this time as the calibration reference state, and record the calibration reference voltage Ui of the tension and compression balance 13 under the calibration reference state;

[0173] Step 6: Collect the voltage values ​​of the tension and compression balance 13 at the side wall balance 1 at 0° roll angle, 90° roll angle, 180° roll angle, and 270° roll angle, and then obtain the absolute natural zero point of the tension and compression balance 13 , The calculation formula is:

[0174] ;

[0175] Step 7: Calculate the voltage difference between the calibration reference state and the absolute natural zero point :

[0176] ... (2);

[0177] According to formula (1) and formula (2), the load value P of the tension and compression balance 13 under the calibration reference state is calculated as follows: n0 , n is an integer from 1 to 6;

[0178] Step 8: P n0 For reference, balance the side wall balance 1 so that P n0 Within ±20% FS, and record P n0 Numeric value;

[0179] Step 9: Perform joint calibration on the side wall balance 1 to balance the P n0 The value is zero point, and a joint calibration load table is prepared according to the range. The load table format is as follows:

[0180] ;

[0181] The corresponding load values ​​of the tension and compression balance 13 are as follows:

[0182] ;

[0183] Step 10: Perform bridge calculation on the matrix column vector of the load value of the tension and compression balance 13 in step 9. The load measurement value of the tension and compression balance 13 after bridge assembly is:

[0184] ;

[0185] Step 11: Using the applied load matrix as the independent variable and the load measurement value of the tension and compression balance 13 after the bridge is assembled as the dependent variable, the implicit second-order relationship between the applied load and the load increment of each tension and compression balance 13 is obtained by the least squares method. The balance formula is:

[0186] ;

[0187] Where:

[0188] is the calculated load value of the nth component of the sidewall balance 1, where n is an integer from 1 to 6;

[0189] The load measurement value of the tension and compression balance 13 after loading the bridge of the nth component group of the side wall balance 1;

[0190] is the intercept term of the nth component;

[0191] is the principal term coefficient of the nth component of the sidewall balance 1;

[0192] is the one-time interference coefficient of the j-th component of the loaded sidewall balance 1 on the n-th component;

[0193] is the square interference coefficient of the jth component of the loaded side wall balance 1 on the nth component;

[0194] is the cross-interference coefficient of the j-th component and the k-th component on the n-th component of the loaded sidewall balance 1;

[0195] Step 12: Connect the model under test 3 to the low-flux thermal insulation flange 2, place the model under test 3 in the test section, level the model under test 3, and mount weights on the loading hole of the model's torque reference point. After loading, reset the mechanism and obtain the relative measured load values ​​of the side wall balance 1 at 0° roll angle, 90° roll angle, 180° roll angle, and 270° roll angle. Calculate the installation angle and the distance between the two centers according to the following six formulas:

[0196] ;

[0197] ;

[0198] ;

[0199] ;

[0200] ;

[0201] ;

[0202] Where:

[0203] is the installation angle of the measured model 3 in the pitch direction relative to the side wall balance 1;

[0204] is the installation angle of the model under test 3 relative to the sidewall balance 1 in the yaw direction;

[0205] is the installation angle of the roll direction of the model 3 to be tested relative to the sidewall balance 1;

[0206] 、 、 Not dependent on load changes;

[0207] is the axial force measured on the side wall balance 1 after the weight is loaded at a roll angle of 0°;

[0208] The axial force load value of the side wall balance 1 after loading the weight at a 90° roll angle;

[0209] The axial force measured on the side wall balance 1 after the weight is loaded at a roll angle of 180°;

[0210] The axial force measured on the side wall balance 1 after the weight is loaded at a roll angle of 270°;

[0211] is the measured value of the normal force on the side wall balance 1 after loading the weight at a roll angle of 0°;

[0212] The normal force measured on the side wall balance 1 after the weight is loaded at a 90° roll angle;

[0213] The normal force measured on the side wall balance 1 after the weight is loaded at a roll angle of 180°;

[0214] The normal force measured on the side wall balance 1 after the weight is loaded at a roll angle of 270°;

[0215] is the measured value of the lateral force of the side wall balance 1 after loading the weight at a roll angle of 0°;

[0216] The measured value of the lateral force of the side wall balance 1 after loading the weight at a roll angle of 90°;

[0217] The measured value of the lateral force of the side wall balance 1 after loading the weight at a roll angle of 180°;

[0218] The measured value of the lateral force of the side wall balance 1 after loading the weight at a roll angle of 270°;

[0219] is the measured value of the rolling moment of the side wall balance 1 after the weight is loaded at a roll angle of 0°;

[0220] The rolling moment measurement value of the side wall balance 1 after the weight is loaded at a rolling angle of 90°;

[0221] The rolling moment measurement value of the side wall balance 1 after the weight is loaded at a rolling angle of 180°;

[0222] The rolling moment measurement value of the side wall balance 1 after the weight is loaded at a rolling angle of 270°;

[0223] is the measured value of the yaw moment of the sidewall balance 1 after the weight is loaded at a roll angle of 0°;

[0224] is the measured value of the yaw moment of the side wall balance 1 after the weight is loaded at a roll angle of 90°;

[0225] The yaw moment measurement value of the side wall balance 1 after the weight is loaded at a roll angle of 180°;

[0226] The yaw moment measurement value of the side wall balance 1 after the weight is loaded at a roll angle of 270°;

[0227] is the measured value of the pitching moment of the side wall balance 1 after the weight is loaded at a roll angle of 0°;

[0228] is the measured value of the pitching moment of the side wall balance 1 after the weight is loaded at a roll angle of 90°;

[0229] is the measured value of the pitching moment of the side wall balance 1 after the weight is loaded at a roll angle of 180°;

[0230] is the measured value of the pitching moment of the side wall balance 1 after the weight is loaded at a roll angle of 270°;

[0231] is the distance between the calibration center and the torque reference point along the x-axis;

[0232] is the distance between the calibration center and the torque reference point along the y-axis;

[0233] is the distance between the calibration center and the torque reference point along the z-axis;

[0234] Note: The calibration center is in front and positive. The calibration center is positive at the top, The calibration center is positive on the right;

[0235] Step 13: Measure the elastic deformation angle of the side wall balance 1-low heat flux insulation flange 2 under the action of longitudinal force, transverse force, longitudinal moment and transverse moment, obtain the angle change - balance measurement load data set, and use multivariate fitting to obtain the elastic angle correction formula:

[0236] ;

[0237] ;

[0238] ;

[0239] Where:

[0240] To measure the elastic angle of the side wall balance 1 in the pitch direction;

[0241] To measure the yaw direction elastic angle of the side wall balance 1;

[0242] To measure the elastic angle of the sidewall balance 1 in the rolling direction, 、 、 Related to load;

[0243] Mz is the pitching moment of the sidewall balance 1;

[0244] X is the axial force of the side wall balance 1;

[0245] My is the yaw moment of the sidewall balance 1;

[0246] Y is the normal force of the side wall balance 1;

[0247] Mx is the rolling moment of the sidewall balance 1;

[0248] is the elastic angle correction coefficient of the pitching moment Mz, which is an undetermined coefficient;

[0249] is the elastic angle correction coefficient of the axial force X, which is an undetermined coefficient;

[0250] is the elastic angle correction coefficient of the yaw moment My, which is an undetermined coefficient;

[0251] is the elastic angle correction coefficient of the normal force Y, which is an undetermined coefficient;

[0252] is the elastic angle correction coefficient of the rolling moment Mx, which is an undetermined coefficient;

[0253] Step 14: Prepare for the wind tunnel test and measure the absolute natural zero point according to step 6;

[0254] Step 15: Measure the deadweight load F of the corresponding sidewall balance 1 according to the sequence of preset attitude angles θ off The preset attitude angle θ is a sequence of values ​​set according to test requirements, such as -4°, -2°, 0°, 2°, 4°, 6°, 8°, 10°, 12°, 14°, 16°, 18°, and 20°.

[0255] Step 16: Perform a wind blowing test at a preset attitude angle θ;

[0256] Step 17: Calculate the load F on the side wall balance 1 after blowing on Relative to deadweight load F off the increment;

[0257] Step 18: Calculate the load increment elastic angle generated after blowing according to the elastic angle correction formula obtained in step 13 ;

[0258] Step 19: Compare the preset attitude angle θ when there is no wind with the incremental elastic angle θ of the wind load obtained in step 18. eAdd them together to obtain the corrected wind-blowing attitude angle, and calculate the wind-free deadweight load corresponding to the corrected attitude angle value by interpolation. , forming a modified deadweight load sequence;

[0259] Step 20: Repeat steps 17 to 19. off With the corrected no-wind deadweight load The iteration stops when the difference is less than or equal to 0.05% FS;

[0260] Step 21: Calculate the six-element loads Y, Mz, Mx, X, Z, and My in the balance coordinate system after deducting its own weight;

[0261] Step 22: Establish the model body axis coordinate system x1y1z1. The z1 axis of the model body axis coordinate system coincides with the z axis of the balance coordinate system, and the positive direction is the same. The origin of the model body axis coordinate system is located on the end face of the measured model 3 close to the side wall balance 1. Ignore the resistance at the bottom of the measured model 3. Convert the six-element load in the balance coordinate system to the model body axis coordinate system. 、 and The order of magnitude is too small, so the effect of the rotation order on the coordinate transformation can be ignored. The rotation order is agreed to be zyx, and the transformation matrix from the balance coordinate system to the model body axis coordinate system is:

[0262] ;

[0263] Then the force and moment in the balance coordinate system are converted to the force and moment in the model body axis coordinate system:

[0264] ;

[0265] ;

[0266] in:

[0267] The force vector converted to the model axis system is positive along the positive direction of the coordinate axis;

[0268] To convert the moment vector into the model axis system, the positive direction around the coordinate axis is positive;

[0269] F is the force under the balance axis;

[0270] M is the moment under the balance axis;

[0271] is the roll angle under the balance axis system;

[0272] ;

[0273] ;

[0274] .

[0275] The present invention uses a positioning tool 9 to pre-install the side wall balance 1, effectively ensuring the accurate positioning and assembly of the side wall balance 1. The structure of the expansion sleeve 12 and the expansion core 11 is used to give axial freedom during installation. At the same time, combined with the radial low stiffness characteristics of the longitudinal and transverse decoupling cross pivot 15, the problem of over-constraint in the assembly of the side wall balance 1 is avoided.

[0276] The present invention proposes an overall calibration method for the side wall balance 1 based on the load measurement value of the tension and compression balance 13, and obtains the second-order relationship balance formula between the force and torque of the side wall balance 1 and the forces of each tension and compression balance 13. After one overall calibration, subsequent replacement of tension and compression balances 13 with different ranges or finished tension and compression sensors does not require further overall calibration.

[0277] The present invention innovatively proposes a method for calculating the measured model 3 and the installation angle and the two-center distance of the balance based on the self-load of the tension and compression balance 13, which solves the technical problem that the side wall balance 1 cannot obtain all the installation angles and the two-center distances, and breaks the limitation of low accuracy of measuring the installation angle and the two-center distance using a ruler in wind tunnel tests.

[0278] The present invention innovatively proposes a deadweight iteration method based on elastic angle compensation, which improves the force and torque measurement accuracy. This method can be extended to full-mode force measurement tests.

[0279] The above embodiments are merely illustrative of the present invention and do not limit its scope of protection. Those skilled in the art may make partial changes thereto, which are within the scope of protection of the present invention as long as they do not exceed the spirit of the present invention.

Claims

1. A sidewall balance system for measuring biomimetic flexible skin wings, characterized by: The invention comprises a side wall balance (1), a low heat flux insulation flange (2) and a model to be tested (3), wherein the side wall balance (1) is installed in the side wall of the test section, the side wall balance (1) comprises a floating plate (6), a fixed plate (7), a force measuring assembly (8) and a high-precision dual-axis angle sensor (10), the fixed plate (7) and the floating plate (6) are set to be coaxially arranged left and right, a balance coordinate system xyz is established on the side wall balance (1), the z axis of the balance coordinate system is set to coincide with the axis of the floating plate (6) and the fixed plate (7), and the right direction is positive, the y axis of the balance coordinate system is set to be positive upward, and the x axis of the balance coordinate system is set to be positive forward, the model to be tested (3) is connected to the right side of the floating plate (6) through the low heat flux insulation flange (2), and the model to be tested (3) is in the incoming flow in the test section; The measured model (3) is a bionic flexible skin wing, a high-precision dual-axis angle sensor (10) is arranged on a floating plate (6), and a force measuring assembly (8) includes six force measuring units, which are divided into three lateral force units (24), two longitudinal force units (25) and one transverse force unit (26). The lateral force unit (24) is arranged parallel to the z-axis, and the lateral force unit (24) arranged directly above the z-axis is marked as P1, the lateral force unit (24) arranged below the rear of the z-axis is marked as P2, and the lateral force unit (24) arranged below the front of the z-axis is marked as P3. P2 and P3 is symmetrical about the yz plane, the three lateral force units (24) are arranged in an isosceles triangle, the axes of the three lateral force units (24) are equidistant from the z axis, the lateral force unit (26) is arranged along the x axis, and the lateral force unit (26) is marked as P6, the two longitudinal force units (25) are arranged symmetrically about the yz plane, and the longitudinal force unit (25) is parallel to the y axis, the longitudinal force unit (25) arranged behind the z axis is marked as P4, and the longitudinal force unit (25) arranged in front of the z axis is marked as P5, and both ends of the six force measuring units are respectively connected to the floating plate (6) and the fixed plate (7).

2. A sidewall balance system for measuring biomimetic flexible skin wings according to claim 1, characterized in that: The force measuring unit comprises an expansion core (11), an expansion sleeve (12), a tension-compression balance (13), a longitudinal and transverse decoupling cross pivot (15) and an end connection flange (16); the expansion sleeve (12) is sleeved on the expansion core (11); the expansion core (11) is connected to the tension-compression balance (13), the longitudinal and transverse decoupling cross pivot (15), the end connection flange (16) and the floating plate (6) in sequence; six connection holes are opened on the fixed plate (7); the outer periphery of the expansion sleeve (12) is tightly connected to the inner periphery of the corresponding connection holes.

3. The sidewall balance system for measuring a biomimetic flexible skin wing according to claim 2, characterized in that: The longitudinal and transverse decoupling cross pivot (15) comprises a set of weakened openings (22) arranged transversely with a span of 100 mm to 150 mm and a set of weakened openings (22) arranged longitudinally with a span of 100 mm to 150 mm, and the width of the weakened openings (22) is 0.5 mm to 2 mm.

4. The sidewall balance system for measuring a biomimetic flexible skin wing according to claim 3, characterized in that: A preload washer (14) is provided between the tension-compression balance (13) and the longitudinal and transverse decoupling cross pivot (15), and the preload force of the preload washer (14) is greater than or equal to 120% of the measuring range of the tension-compression balance (13).

5. The sidewall balance system for measuring biomimetic flexible skin wings according to claim 1, characterized in that: The labyrinth seal (5) and the boundary layer plate (4) are sequentially sleeved on the low heat flux insulation flange (2) from the inside to the outside, and a labyrinth flow channel (23) is formed between the labyrinth seal (5) and the boundary layer plate (4).

6. The sidewall balance system for measuring a biomimetic flexible skin wing according to claim 1, characterized in that: The low heat flux insulation flange (2) is a necked flange, and a plurality of L-shaped slit structures (27) are provided on the flange neck of the low heat flux insulation flange (2), and the total length of the plurality of slit structures (27) in the circumferential direction is greater than or equal to one quarter of the circumference of the flange neck.

7. The sidewall balance system for measuring a biomimetic flexible skin wing according to claim 1, characterized in that: A low thermal conductivity insulation gasket (17) is provided between the low heat flux insulation flange (2) and the side wall balance (1).

8. A method for measuring a bionic flexible skin wing, implemented by using a sidewall balance system for measuring a bionic flexible skin wing according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: There are several tension and compression balances (13), and a suitable tension and compression balance (13) is selected according to the force measurement range of the wind tunnel test; Step 2: Perform single-component calibration on each tension-compression balance (13) to obtain a linear relationship between the calculated load value of the tension-compression balance (13) and the increment of the output voltage value of the tension-compression balance (13): ……（1）； Where: is the calculated load value of the nth tension-compression balance (13), where n is an integer from 1 to 6; is the intercept term; is the principal term coefficient of the nth tension-compression balance (13); is the voltage increment generated by the nth tension-compression balance (13) under load; Step 3: Make a positioning tool (9), the floating plate (6) and the fixed plate (7) are each provided with three stepped holes, the stepped holes on the floating plate (6) and the fixed plate (7) are coaxially aligned one by one, the positioning tool (9) comprises a locking screw (19), an annular positioning sleeve (20) and a positioning pin (21), one end of the positioning pin (21) is provided with a shoulder, the shoulder of the positioning pin (21) is matched with the stepped hole stop of the floating plate (6), and is connected by a screw, the annular positioning sleeve (20) is sleeved on the other end of the positioning pin (21), the outer periphery of the annular positioning sleeve (20) is matched with the stepped hole corresponding to the fixed plate (7), and is tightened and fixed by the locking screw (19), thereby realizing the initial fixation of the floating plate (6) and the fixed plate (7); Step 4: Install the sidewall balance (1) on the calibration table. After the sidewall balance (1) works normally, remove the annular positioning sleeve (20) and loosen the locking screw (19) to leave a gap between the locking screw (19) and the fixed plate (7); Step 5: Connect the low heat flux insulation flange (2), adjust the roll angle and pitch angle of the side wall balance (1) through the calibration table so that the reading of the high-precision dual-axis angle sensor (10) is 0±0.05°, and mark the state of the side wall balance (1) at this time as the calibration reference state, and record the calibration reference voltage Ui of the tension and compression balance (13) under the calibration reference state; Step 6: Collect the voltage values ​​of the tension and compression balance (13) at the side wall balance (1) at 0° roll angle, 90° roll angle, 180° roll angle, and 270° roll angle, and then obtain the absolute natural zero point of the tension and compression balance (13) , The calculation formula is: ……（2）； Step 7: Calculate the voltage difference between the calibration reference state and the absolute natural zero point : ……（3）； According to equations (1) and (3), the load value P of the tension-compression balance (13) under the calibration reference state is calculated as follows: n0 , n is an integer from 1 to 6; Step 8: P n0 For reference, balance the sidewall balance (1) so that P n0 Within ±20% FS, and record P n0 Numeric value; Step 9: Perform joint calibration on the side wall balance (1) to obtain the balanced P n0 The value is zero point, and a joint calibration load table is prepared according to the range. The load table format is as follows: ； The corresponding load values ​​of the tension-compression balance (13) are as follows: ； Step 10: Perform bridge calculation on the matrix column vector of the load value of the tension-compression balance (13) in step 9. The load measurement value of the tension-compression balance (13) after bridge assembly is: ； Step 11: With the applied load matrix as the independent variable and the load measurement value of the tension-compression balance (13) after the bridge is assembled as the dependent variable, the implicit second-order relationship between the applied load and the load increment of each tension-compression balance (13) is obtained by the least squares method. The balance formula is: ； Where: is the calculated load value of the nth component of the sidewall balance (1), where n is an integer from 1 to 6; is the load measurement value of the tension and compression balance (13) after the bridge of the nth component group loaded on the side wall balance (1); is the intercept term of the nth component; is the principal term coefficient of the nth component of the sidewall balance (1); is the one-time interference coefficient of the jth component on the nth component of the loaded sidewall balance (1); is the square interference coefficient of the jth component on the nth component of the loaded sidewall balance (1); is the cross-interference coefficient of the jth component and the kth component on the nth component of the loaded sidewall balance (1); Step 12: Connect the model under test (3) to the low heat flux insulation flange (2) so that the model under test (3) is in the test section, level the model under test (3), and mount weights on the moment reference point loading hole of the model. After loading, the mechanism needs to be reset to obtain the relative measurement load values ​​of the side wall balance (1) at 0° roll angle, 90° roll angle, 180° roll angle, and 270° roll angle. Calculate the installation angle and the distance between the two centers according to the following six formulas: ； ； ； ； ； ； Where: is the pitch direction installation angle of the measured model (3) relative to the side wall balance (1); is the yaw installation angle of the model under test (3) relative to the sidewall balance (1); is the installation angle of the tested model (3) relative to the sidewall balance (1) in the rolling direction; is the axial force measured on the side wall balance (1) after the weight is loaded at a roll angle of 0°; is the axial force load value of the side wall balance (1) after the weight is loaded at a roll angle of 90°; The axial force measured on the side wall balance (1) after the weight is loaded at a roll angle of 180°; The axial force measured on the side wall balance (1) after the weight is loaded at a roll angle of 270°; is the normal force measured on the sidewall balance (1) after the weight is loaded at a roll angle of 0°; is the measured value of the normal force on the side wall balance (1) after the weight is loaded at a roll angle of 90°; is the measured value of the normal force on the side wall balance (1) after the weight is loaded at a roll angle of 180°; is the measured value of the normal force on the side wall balance (1) after the weight is loaded at a roll angle of 270°; is the measured value of the lateral force of the side wall balance (1) after loading the weight at a roll angle of 0°; is the measured value of the lateral force of the side wall balance (1) after loading the weight at a roll angle of 90°; is the measured value of the lateral force of the side wall balance (1) after loading the weight at a roll angle of 180°; is the measured value of the lateral force of the side wall balance (1) after loading the weight at a roll angle of 270°; is the measured value of the rolling moment of the side wall balance (1) after the weight is loaded at a rolling angle of 0°; is the measured value of the rolling moment of the side wall balance (1) after the weight is loaded at a rolling angle of 90°; is the measured value of the rolling moment of the side wall balance (1) after the weight is loaded at a rolling angle of 180°; The measured value of the rolling moment of the side wall balance (1) after the weight is loaded at a rolling angle of 270°; is the yaw moment measurement value of the sidewall balance (1) after loading the weight at a roll angle of 0°; is the measured value of the yaw moment of the sidewall balance (1) after the weight is loaded at a roll angle of 90°; is the yaw moment measurement value of the side wall balance (1) after the weight is loaded at a roll angle of 180°; is the measured value of the yaw moment of the sidewall balance (1) after the weight is loaded at a roll angle of 270°; is the measured value of the pitching moment of the side wall balance (1) after the weight is loaded at a roll angle of 0°; is the measured value of the pitching moment of the side wall balance (1) after the weight is loaded at a roll angle of 90°; is the measured value of the pitching moment of the side wall balance (1) after the weight is loaded at a roll angle of 180°; is the measured value of the pitching moment of the side wall balance (1) after the weight is loaded at a roll angle of 270°; is the distance between the calibration center and the torque reference point along the x-axis; is the distance between the calibration center and the torque reference point along the y-axis; is the distance between the calibration center and the torque reference point along the z-axis; Step 13: Measure the elastic deformation angles of the side wall balance (1) and the low heat flux insulation flange (2) under the action of longitudinal force, transverse force, longitudinal moment and transverse moment, obtain the angle change - balance measurement load data set, and use multivariate fitting to obtain the elastic angle correction formula: ； ； ； Where: is the elastic angle of the side wall balance (1) in the pitch direction; is the elastic angle of the sidewall balance (1) in the yaw direction; is the elastic angle of the sidewall balance (1) in the rolling direction; Mz is the pitching moment of the sidewall balance (1); X is the axial force of the side wall balance (1); My is the yaw moment of the sidewall balance (1); Y is the normal force of the side wall balance (1); Mx is the rolling moment of the sidewall balance (1); is the elastic angle correction coefficient of the pitching moment Mz; is the elastic angle correction coefficient of the axial force X; is the elastic angle correction coefficient of the yaw moment My; is the elastic angle correction coefficient of the normal force Y; is the elastic angle correction coefficient of the rolling moment Mx; Step 14: Prepare for the wind tunnel test and measure the absolute natural zero point according to step 6; Step 15: Measure the deadweight load F of the corresponding side wall balance (1) according to the sequence of preset attitude angles θ off ; Step 16: Perform a wind blowing test at a preset attitude angle θ; Step 17: Calculate the side wall balance (1) load F after blowing on Relative to deadweight load F off the increment; Step 18: Calculate the load increment elastic angle θ generated after blowing according to the elastic angle correction formula obtained in step 13 e ; Step 19: Compare the preset attitude angle θ when there is no wind with the incremental elastic angle θ of the wind load obtained in step 18. e Add them together to obtain the corrected wind-blowing attitude angle, and calculate the wind-free deadweight load F' corresponding to the corrected attitude angle value by interpolation off , forming a modified deadweight load sequence; Step 20: Repeat steps 17 to 19. off and the corrected no-wind deadweight load F′ off The iteration stops when the difference is less than or equal to 0.05% FS; Step 21: Calculate the six-element loads Y, Mz, Mx, X, Z, and My in the balance coordinate system after deducting its own weight; Step 22: Establish the model body axis coordinate system x1y1z1. The z1 axis of the model body axis coordinate system coincides with the z axis of the balance coordinate system, and the positive directions are the same. The origin of the model body axis coordinate system is located on the end face of the measured model (3) close to the side wall balance (1). Ignore the resistance at the bottom of the measured model (3). Convert the six-element load in the balance coordinate system to the model body axis coordinate system. 、 and The order of magnitude is too small, so the effect of the rotation order on the coordinate transformation can be ignored. The rotation order is agreed to be zyx, and the transformation matrix from the balance coordinate system to the model body axis coordinate system is: ； Then the force and moment in the balance coordinate system are converted to the force and moment in the model body axis coordinate system: ； ； in: The force vector converted to the model axis system is positive along the positive direction of the coordinate axis; To convert the moment vector into the model axis system, the positive direction around the coordinate axis is positive; F is the force under the balance axis; M is the moment under the balance axis; is the roll angle under the balance axis system; ； ； 。

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