A high-precision deformation measurement device and method for a balance based on binocular vision

Abstract

The present invention belongs to the technical field of high-speed wind tunnel test, and discloses a high-precision deformation measurement device and method for a balance based on binocular vision. In the measurement device, a balance to be measured is fixed on the upper surface of a vibration isolation table through a balance support mechanism, and a binocular vision camera system is fixed through a binocular vision system support mechanism; the binocular vision camera system photographs the balance to be measured. The measurement method includes photographing a marker point image; performing an initial positioning of edge points; performing sub-pixel edge detection; performing least square fitting of edge points; performing secondary fitting of edge points; calculating the deformation amount of the balance to be measured; and determining whether to replace the balance to be measured. The high-precision deformation measurement device and method for a balance based on binocular vision of the present invention realize high-precision measurement of the balance deformation without damaging the balance, and provide technical guarantee for the reliable application of high-speed wind tunnel balances.

Description

Technical Field

[0001] The present invention belongs to the technical field of high - speed wind tunnel tests, and particularly relates to a high - precision deformation measurement device and method for a balance based on binocular vision. Background Art

[0002] Currently, in high - speed wind tunnel tests, when plastic deformation occurs or cracks appear in the structural components of the balance, the balance signal will be abnormal. It is extremely time - consuming and laborious to determine whether the balance has deformed, whether it can continue to be used, and whether manual repeated pasting and calibration are required by collecting signal data. Once it is not timely determined that the data abnormality is caused by the balance, it is easy to spend a lot of time checking each related system of the high - speed wind tunnel one by one, resulting in a long - term interruption of the high - speed wind tunnel test and affecting the quality and efficiency of the high - speed wind tunnel test.

[0003] Currently, there is an urgent need to develop a high - precision deformation measurement device and method for a balance based on binocular vision. Summary of the Invention

[0004] One technical problem to be solved by the present invention is to provide a high - precision deformation measurement device for a balance based on binocular vision, and another technical problem to be solved by the present invention is to provide a high - precision deformation measurement method for a balance based on binocular vision to overcome the defects of the prior art.

[0005] The high - precision deformation measurement device for a balance based on binocular vision of the present invention fixes the balance to be measured on the upper surface of the vibration isolation table through a balance support mechanism, and fixes the binocular vision camera system through a binocular vision system support mechanism;

[0006] The balance support mechanism includes a horizontal balance bracket, and a balance roll angle adjustment block is fixed at the rear end of the balance bracket; the balance to be measured is a rod - type balance, the rear end of the balance to be measured is a fixed end, which is inserted into the balance roll angle adjustment block; the front end of the balance to be measured is a suspended end, and the rod body is suspended above the balance bracket;

[0007] The binocular vision system support mechanism includes a lateral displacement stage and a vertical displacement stage; the lateral displacement stage is parallel to the balance bracket, a vertical displacement stage is fixed on the lateral displacement stage, and a binocular vision camera system is fixed on the vertical displacement stage, and the binocular vision camera system photographs the balance to be measured;

[0008] Marking points are pasted on the balance to be measured, the marking points are round dots, and the diameter range of the round dots is 1 mm to 3 mm.

[0009] Further, the vibration isolation table is a damping optical vibration isolation table, the material is stainless steel, the tabletop of the vibration isolation table is a three - layer sandwich honeycomb structure, the upper surface of the tabletop is subjected to a Midi - pattern matte treatment, and a polymer composite damping rubber vibration isolation pad is arranged at the bottom of the tabletop; the amplitude of the vibration isolation table is less than 4 μm, and the flatness is 0.02 - 0.05 mm / m2 。

[0010] Furthermore, the balance support includes a positioning block and a balance horizontal support plate connected in sequence from front to back, and the balance horizontal support plate is connected to a balance roll angle adjustment block;

[0011] The positioning block is provided with a plurality of threaded holes Ⅰ corresponding to the screw holes on the surface of the vibration isolation table, and the positioning block is fixed by bolts passing through the threaded holes Ⅰ from top to bottom and inserted into the screw holes on the surface of the vibration isolation table;

[0012] The balance roll angle adjustment block is provided with a plurality of threaded holes Ⅵ corresponding to the screw holes on the surface of the vibration isolation table, and the balance roll angle adjustment block is fixed by bolts passing through the threaded holes Ⅵ from top to bottom and inserted into the screw holes on the surface of the vibration isolation table; a flange is fixed on the rear end face of the balance adapter, a plurality of flange holes are arranged in the circumferential direction of the flange, and the balance adapter is fixed on the front end face of the balance roll angle adjustment block by screws passing through the flange holes; a tapered hole is arranged on the front end face of the balance adapter, and the tapered section at the rear end of the measured balance is inserted into the tapered hole for fixation;

[0013] The balance roll angle adjustment block adjusts the roll angle of the measured balance.

[0014] Furthermore, the lateral displacement table is a horizontal square flat plate; the edge of the lateral displacement table is provided with a plurality of threaded holes Ⅶ corresponding to the screw holes on the surface of the vibration isolation table, and the lateral displacement table is fixed by bolts passing through the threaded holes Ⅶ from top to bottom and inserted into the screw holes on the surface of the vibration isolation table; a protruding lateral displacement table guide rail is arranged on the horizontal central axis of the lateral displacement table, and sunken lateral displacement table card slots are arranged on both sides of the lateral displacement table guide rail;

[0015] The vertical displacement table is a vertical square flat plate; a reinforcing rib is arranged on the back of the vertical displacement table; a plurality of threaded holes Ⅱ are arranged on the edge of the vertical displacement table; the lower end of the vertical displacement table is mounted on the lateral displacement table guide rail and the lateral displacement table card slot of the lateral displacement table through a slider Ⅱ, and the vertical displacement table moves back and forth along the lateral displacement table guide rail and the lateral displacement table card slot through the slider Ⅱ, and is positioned and fixed by tightening the positioning bolts matching the lateral displacement table card slot of the slider Ⅱ; the front face of the vertical displacement table faces the balance support, a protruding vertical displacement table guide rail is arranged on the vertical central axis of the front face of the vertical displacement table, and sunken vertical displacement table card slots are arranged on both sides of the vertical displacement table guide rail; a slider Ⅰ is mounted on the vertical displacement table guide rail and the vertical displacement table card slot, the slider Ⅰ moves up and down along the vertical displacement table guide rail and the vertical displacement table card slot, and a threaded hole Ⅲ is arranged on the slider Ⅰ, and the threaded hole Ⅲ corresponds to the threaded hole Ⅱ; the slider Ⅰ is assisted to be fixed by tightening the positioning screws on the slider Ⅰ matching the vertical displacement table card slot.

[0016] Furthermore, the binocular vision camera system is fixedly installed through an L-shaped binocular vision camera support;

[0017] The vertical plate of the binocular vision camera bracket matches the front end face of the slider Ⅰ. There is a threaded hole Ⅳ on the vertical plate, which matches the threaded hole Ⅲ on the slider Ⅰ. The binocular vision camera bracket is fixed by a bolt assembly passing through the threaded hole Ⅳ, the threaded hole Ⅲ and the threaded hole Ⅱ.

[0018] The front end of the horizontal plate of the L-shaped binocular vision camera bracket is connected to the telescopic connecting plate of the camera bracket by means of fixing with track mounting screws; the lower surface of the front end of the telescopic connecting plate of the camera bracket is connected to the cross beam by means of fixing with track mounting screws; the cross beam is parallel to the measured balance, and the front end face of the cross beam is fixed with a front mounting plate of the camera bracket. There are several threaded holes Ⅴ on the front mounting plate of the camera bracket. The right camera and the left camera are fixed on the cross beam by screws screwed into the threaded holes Ⅴ.

[0019] There is a strip light source on the central axis of the lower surface of the cross beam, and a data acquisition module is arranged on the upper surface of the cross beam. The right camera and the left camera are respectively connected to the data acquisition module by cables, and the data acquisition module is connected to the computer by a cable; the images taken by the right camera and the left camera are transmitted to the computer through the data acquisition module.

[0020] The binocular vision camera system moves forward and backward through the slider Ⅱ, moves up and down through the slider Ⅰ, and moves left and right through the telescopic connecting plate of the camera bracket; it also supplements the forward and backward movement through the cross beam, and the telescopic connecting plate of the camera bracket supplements the left and right movement.

[0021] The high-precision deformation measurement method of the balance based on binocular vision of the present invention includes the following steps:

[0022] S10. Take images of the marked points;

[0023] The right camera and the left camera synchronously collect the images of the marked points of the measured balance, match the marked points with the digital model of the measured balance, and obtain the model coordinates of the marked points.

[0024] S20. Initial positioning of edge points;

[0025] The Canny pixel edge detection algorithm is used to process the grayscale images taken by the right camera and the left camera to obtain edge points with 1 pixel point as the basic unit, which are defined as roughly positioned edge points.

[0026] S30. Sub-pixel edge detection;

[0027] The gradient amplitude mean method is used to improve the accuracy of the edge from 1 pixel point to 0.1 pixel point to obtain precisely positioned edge points.

[0028] S40. Least squares fitting of edge points;

[0029] The following general equation of a plane ellipse is used to fit the ellipse to obtain the parameters B, C, D, E, F:

[0030] ;

[0031] Calculate the coordinates of the ellipse center according to the following formula:

[0032] ;

[0033] where, x 、 y are the abscissa and ordinate values of a point on the ellipse respectively; x 0, y 0 are the abscissa and ordinate values of the ellipse center respectively;

[0034] S50. Quadratic fitting of edge points;

[0035] After the first fitting, calculate the residual of each edge point, remove the edge points that exceed the preset residual threshold, and then perform a second least squares fitting on the remaining edge points to obtain the edge point image;

[0036] S60. Calculate the deformation of the measured balance;

[0037] Compare the original image at the marked points of the measured balance and the dot image composed of the edge points of the marked points, and calculate the deformation of the measured balance;

[0038] S70. Determine whether to replace the measured balance;

[0039] If the deformation exceeds 5 μm, it is determined that the structural elements of the measured balance have undergone plastic deformation or cracks, and it is necessary to suspend the high-speed wind tunnel test and replace the measured balance.

[0040] Furthermore, the gradient magnitude mean method includes the following steps:

[0041] S31. Calculate the gradient magnitude along the gradient direction on the roughly located edge points ;

[0042] S32. Determine the value range of the accurately located edge points that satisfy the gradient magnitude under the preset threshold ;

[0043] S33. Take the gradient components and as weights, and obtain the accurately located edge point position according to the following sub-pixel correction formula of the edge position along the gradient direction:

[0044] ;

[0045] where, and is the distance component of a pixel point along the gradient direction from the roughly located edge point; and is the gradient component of a pixel point along the gradient direction from the roughly located edge point; is the number of pixel points along the gradient direction; is along x the sub - pixel variable value of the edge position along the gradient direction, is along y the sub - pixel variable value of the edge position along the gradient direction;

[0046] Let the roughly located edge point be , and the gradient direction be , then when , the next two points for calculating the gradient amplitude along the gradient direction are and , where , .

[0047] The high - precision deformation measurement device and method for a balance based on binocular vision of the present invention achieve high - precision measurement of the balance deformation without damaging the balance, providing technical support for the reliable application of high - speed wind tunnel balances. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic structural diagram of the high - precision deformation measurement device for a balance based on binocular vision of the present invention;

[0049] Figure 2 is a schematic structural diagram of the balance support mechanism in the high - precision deformation measurement device for a balance based on binocular vision of the present invention;

[0050] Figure 3 is a schematic structural diagram of the binocular vision system support mechanism in the high - precision deformation measurement device for a balance based on binocular vision of the present invention;

[0051] Figure 4 is a schematic structural diagram of the binocular vision system in the high - precision deformation measurement device for a balance based on binocular vision of the present invention;

[0052] Figure 5 is the marked - point image obtained by the high - precision deformation measurement method for a balance based on binocular vision of the present invention;

[0053] Figure 6 is the fitted ellipse obtained by the high - precision deformation measurement method for a balance based on binocular vision of the present invention;

[0054] Figure 6 In, the red circle is the fitted ellipse of the edge points of the circular mark image, and the red central dot is the center of the fitted ellipse;

[0055] Figure 7 The edge point image obtained by the high-precision deformation measurement method of the balance based on binocular vision of the present invention;

[0056] Figure 8 The schematic diagram of the gradient amplitude mean method adopted by the high-precision deformation measurement method of the balance based on binocular vision of the present invention.

[0057] In the figure, 1. the balance to be measured; 2. the vibration isolation table; 3. the balance support; 4. the balance roll angle adjustment block; 5. the horizontal displacement table; 6. the vertical displacement table; 7. the binocular vision camera system; 8. the balance horizontal support plate; 9. the balance adapter; 10. the taper hole; 11. the flange hole; 12. the flange; 13. the threaded hole I; 14. the positioning bolt; 15. the horizontal displacement table guide rail; 16. the vertical displacement table guide rail; 17. the threaded hole II; 18. the slider I; 19. the positioning screw; 20. the threaded hole III; 21. the binocular vision camera support; 22. the threaded hole IV; 23. the strip light source; 24. the data acquisition module; 25. the right camera; 26. the left camera; 27. the threaded hole V; 28. the front mounting plate of the camera support; 29. the computer; 30. the telescopic connecting plate of the camera support; 31. the cross beam; 32. the threaded hole VI; 33. the positioning block; 34. the threaded hole VII; 35. the slider II; 36. the horizontal displacement table card slot; 37. the vertical displacement table card slot. Specific embodiments

[0058] The following specific examples illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0059] Example: As Figure 1 shown, in this embodiment, the high-precision deformation measurement device of the balance based on binocular vision fixes the balance 1 to be measured on the upper surface of the vibration isolation table 2 through the balance support mechanism, and fixes the binocular vision camera system 7 through the binocular vision system support mechanism;

[0060] The balance support mechanism includes a horizontal balance support 3, and the balance roll angle adjustment block 4 is fixed at the rear end of the balance support 3; the balance 1 to be measured is a lever balance, the rear end of the balance 1 to be measured is a fixed end and is inserted into the balance roll angle adjustment block 4; the front end of the balance 1 to be measured is a suspended end, and the rod body is suspended above the balance support 3;

[0061] The support mechanism of the binocular vision system includes a horizontal displacement stage 5 and a vertical displacement stage 6; the horizontal displacement stage 5 is parallel to the balance support 3, the vertical displacement stage 6 is fixed vertically on the horizontal displacement stage 5, and the binocular vision camera system 7 is fixed on the vertical displacement stage 6. The binocular vision camera system 7 photographs the balance to be measured 1.

[0062] Marking points are pasted on the balance to be measured 1, the marking points are round dots, and the diameter range of the round dots is 1 mm to 3 mm.

[0063] Further, the vibration isolation table 2 is a damping optical vibration isolation table, the material is stainless steel, the tabletop of the vibration isolation table 2 is a three-layer sandwich honeycomb structure, the upper surface of the tabletop is subjected to a Midi pattern matte treatment, and a polymer composite damping rubber vibration isolation pad is arranged at the bottom of the tabletop; the amplitude of the vibration isolation table 2 is less than 4 μm, and the flatness is 0.02 - 0.05 mm / m. 2 。

[0064] Further, as Figure 2 shown, the balance support 3 includes a positioning block 33 and a balance horizontal support plate 8 connected in sequence from front to back, and the balance horizontal support plate 8 is connected to the balance roll angle adjustment block 4;

[0065] A number of threaded holes Ⅰ13 corresponding to the screw holes on the tabletop of the vibration isolation table 2 are arranged on the positioning block 33, and the positioning block 33 is fixed by bolts passing through the threaded holes Ⅰ13 from top to bottom and inserted into the screw holes on the tabletop of the vibration isolation table 2;

[0066] A number of threaded holes Ⅵ32 corresponding to the screw holes on the tabletop of the vibration isolation table 2 are arranged on the balance roll angle adjustment block 4, and the balance roll angle adjustment block 4 is fixed by bolts passing through the threaded holes Ⅵ32 from top to bottom and inserted into the screw holes on the tabletop of the vibration isolation table 2; a flange 12 is fixed on the rear end face of the balance adapter 9, a number of flange holes 11 are arranged circumferentially on the flange 12, and the balance adapter 9 is fixed on the front end face of the balance roll angle adjustment block 4 by screws passing through the flange holes 11; a tapered hole 10 is arranged on the front end face of the balance adapter 9, and the tapered section at the rear end of the balance to be measured 1 is inserted into the tapered hole 10 for fixation;

[0067] The balance roll angle adjustment block 4 adjusts the roll angle of the balance to be measured 1.

[0068] Further, as Figure 3 shown, the horizontal displacement stage 5 is a horizontal square flat plate; a number of threaded holes Ⅶ34 corresponding to the screw holes on the tabletop of the vibration isolation table 2 are arranged on the edge of the horizontal displacement stage 5, and the horizontal displacement stage 5 is fixed by bolts passing through the threaded holes Ⅶ34 from top to bottom and inserted into the screw holes on the tabletop of the vibration isolation table 2; a protruding horizontal displacement stage guide rail 15 is arranged on the horizontal central axis of the horizontal displacement stage 5, and sunken horizontal displacement stage card slots 36 are arranged on both sides of the horizontal displacement stage guide rail 15;

[0069] The vertical displacement stage 6 is a vertical square flat plate; reinforcing ribs are provided on the back surface of the vertical displacement stage 6; a number of threaded holes II 17 are provided on the edge of the vertical displacement stage 6; the lower end of the vertical displacement stage 6 is mounted on the horizontal displacement stage guide rail 15 and the horizontal displacement stage slot 36 of the horizontal displacement stage 5 through the slider II 35. The vertical displacement stage 6 moves back and forth along the horizontal displacement stage guide rail 15 and the horizontal displacement stage slot 36 through the slider II 35, and is positioned and fixed by tightening the positioning bolt 14 that matches the horizontal displacement stage slot 36; the front surface of the vertical displacement stage 6 faces the balance support 3, and a protruding vertical displacement stage guide rail 16 is provided on the vertical central axis of the front surface of the vertical displacement stage 6. Concave vertical displacement stage slots 37 are provided on both sides of the vertical displacement stage guide rail 16; the slider I 18 is mounted on the vertical displacement stage guide rail 16 and the vertical displacement stage slot 37. The slider I 18 moves up and down along the vertical displacement stage guide rail 16 and the vertical displacement stage slot 37. Threaded holes III 20 are provided on the slider I 18, and the threaded holes III 20 correspond to the threaded holes II 17; the slider I 18 is assisted in fixing by tightening the positioning screw 19 that matches the vertical displacement stage slot 37 on the slider I 18.

[0070] Further, as Figure 4 shown, the binocular vision camera system 7 is fixedly installed through the L-shaped binocular vision camera bracket 21;

[0071] The vertical plate of the binocular vision camera bracket 21 matches the front end face of the slider I 18. Threaded holes IV 22 are provided on the vertical plate, and the threaded holes IV 22 match the threaded holes III 20 on the slider I 18. The binocular vision camera bracket 21 is fixed by a bolt assembly passing through the threaded holes IV 22, the threaded holes III 20, and the threaded holes II 17;

[0072] The front end of the horizontal plate of the L-shaped binocular vision camera bracket 21 is connected to the camera bracket telescopic connecting plate 30 by means of fixing with a track mounting screw; the lower surface of the front end of the camera bracket telescopic connecting plate 30 is connected to the cross beam 31 by means of fixing with a track mounting screw; the cross beam 31 is parallel to the measured balance 1, and the front end face of the cross beam 31 is fixed with the camera bracket front mounting plate 28. A number of threaded holes V 27 are provided on the camera bracket front mounting plate 28. The right camera 25 and the left camera 26 are fixed on the cross beam 31 by screws screwed into the threaded holes V 27;

[0073] A strip light source 23 is provided on the central axis of the lower surface of the cross beam 31, a data acquisition module 24 is provided on the upper surface of the cross beam 31, the right camera 25 and the left camera 26 are respectively connected to the data acquisition module 24 by cables, and the data acquisition module 24 is connected to the computer 29 by a cable; the images taken by the right camera 25 and the left camera 26 are transmitted to the computer 29 through the data acquisition module 24;

[0074] The binocular vision camera system 7 moves forward and backward through the slider II 35, moves up and down through the slider I 18, and moves left and right through the telescopic connecting plate 30 of the camera support; the cross beam 31 is also used to supplement the forward and backward movement, and the telescopic connecting plate 30 of the camera support supplements the left and right movement.

[0075] The high-precision deformation measurement method of the balance based on binocular vision in this embodiment includes the following steps:

[0076] S10. Take the image of the marking points;

[0077] The right camera 25 and the left camera 26 synchronously collect the image of the marking points on the balance 1 to be measured as Figure 5 shown, match the marking points with the digital model of the balance 1 to be measured, and obtain the model coordinates of the marking points;

[0078] S20. Initial positioning of edge points;

[0079] Adopt the Canny pixel edge detection algorithm to process the grayscale images taken by the right camera 25 and the left camera 26, and obtain the edge points with 1 pixel point as the basic unit, which are defined as the roughly positioned edge points;

[0080] S30. Sub-pixel edge detection;

[0081] Adopt the gradient amplitude mean method to improve the accuracy of the edge from 1 pixel point to 0.1 pixel point, and obtain the precisely positioned edge points;

[0082] S40. Least squares fitting of edge points;

[0083] As Figure 6 shown, use the following general equation of a plane ellipse to fit the ellipse and obtain the parameters B, C, D, E, F:

[0084] ;

[0085] Calculate the ellipse center coordinates according to the following formula:

[0086] ;

[0087] where x 、 y are the abscissa and ordinate values of a point on the ellipse respectively; x 0、 y 0 are the abscissa and ordinate values of the ellipse center respectively;

[0088] S50. Second fitting of edge points;

[0089] After the first fitting, calculate the residual of each edge point, remove the edge points that exceed the preset residual threshold according to the preset residual threshold, and then perform the second least squares fitting on the remaining edge points to obtain asFigure 7 The edge point image shown

[0090] S60. Calculate the deformation amount of the balance 1 to be measured

[0091] Compare the original image at the marked points of the balance 1 to be measured with the dot image composed of the edge points of the marked points, and calculate the deformation amount of the balance 1 to be measured

[0092] S70. Determine whether to replace the balance 1 to be measured

[0093] If the deformation amount exceeds 5μm, it is determined that the structural elements of the balance 1 to be measured have undergone plastic deformation or cracks, and it is necessary to suspend the high-speed wind tunnel test and replace the balance 1 to be measured

[0094] Furthermore, the gradient amplitude mean method includes the following steps

[0095] S31. Obtain the gradient amplitude along the gradient direction at the roughly located edge points ;

[0096] S32. Determine the value range of the accurately located edge points that meet the gradient amplitude under a preset threshold ;

[0097] S33. Use the gradient components and as weights, and according to the following sub-pixel correction formula for the edge position along the gradient direction, obtain the accurately located edge point position

[0098] ;

[0099] where and are the distance components of a pixel point along the gradient direction from the roughly located edge point and are the gradient components of a pixel point along the gradient direction from the roughly located edge point is the number of pixel points along the gradient direction is the sub-pixel variable value of the edge position along the x gradient direction is the sub-pixel variable value of the edge position along the y gradient direction

[0100] As shown in Figure 8 , let the roughly located edge point be , and the gradient direction be , then when , the next two points for calculating the gradient amplitude along the gradient direction are and , where , .

[0101] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A high-precision deformation measurement method for a balance based on binocular vision, using a high-precision deformation measurement device for a balance based on binocular vision, characterized in that, The described measuring device includes that the upper surface of the vibration isolation table (2) fixes the measured balance (1) through the balance support mechanism, and fixes the binocular vision camera system (7) through the binocular vision system support mechanism; The balance support mechanism includes a horizontal balance bracket (3), and the rear end of the balance bracket (3) fixes the balance roll angle adjustment block (4); the measured balance (1) is a lever balance, the rear end of the measured balance (1) is a fixed end, which is inserted into the balance roll angle adjustment block (4); the front end of the measured balance (1) is a suspended end, and the rod body is suspended above the balance bracket (3); The binocular vision system support mechanism includes a lateral displacement stage (5) and a vertical displacement stage (6); the lateral displacement stage (5) is parallel to the balance bracket (3), the vertical displacement stage (6) is fixed on the lateral displacement stage (5), and the binocular vision camera system (7) is fixed on the vertical displacement stage (6), and the binocular vision camera system (7) photographs the measured balance (1); the binocular vision camera system (7) includes a right camera (25) and a left camera (26); Marking points are pasted on the measured balance (1), the marking points are round dots, and the diameter range of the round dots is 1 mm to 3 mm; The described measuring method includes the following steps: S10. Photograph the marking point images; The right camera (25) and the left camera (26) synchronously collect the marking point images of the measured balance (1), match the marking points with the digital model of the measured balance (1), and obtain the model coordinates of the marking points; S20. Initial positioning of edge points; Adopt the Canny pixel edge detection algorithm to process the grayscale images taken by the right camera (25) and the left camera (26), and obtain edge points with 1 pixel point as the basic unit, which are defined as roughly positioned edge points; S30. Sub-pixel edge detection; Adopt the gradient amplitude mean method to improve the accuracy of the edge from 1 pixel point to 0.1 pixel point, and obtain accurately positioned edge points; S40. Least square fitting of edge points; Use the following general equation of a plane ellipse to fit the ellipse and obtain the parameters B, C, D, E, F: ； Calculate the ellipse center coordinates according to the following formula: ； wherein, are respectively the abscissa and ordinate values of a point on the ellipse; are respectively the abscissa and ordinate values of the center of the ellipse; S50. Secondary fitting of edge points; After the first fitting, calculate the residual of each edge point, remove the edge points that exceed the preset residual threshold according to the preset residual threshold, and then perform a second least square fitting on the remaining edge points to obtain the edge point image; S60. Calculate the deformation of the measured balance (1); Compare the original image at the marking points of the measured balance (1) with the round dot image composed of the edge points of the marking points, and calculate the deformation of the measured balance (1); S70. Determine whether to replace the measured balance (1); If the deformation exceeds 5 μm, it is determined that the structural components of the measured balance (1) have undergone plastic deformation or cracks, and it is necessary to suspend the high-speed wind tunnel test and replace the measured balance (1).

2. The high-precision deformation measurement method of the balance based on binocular vision according to claim 1, wherein The isolation table (2) mentioned above is a damped optical isolation table, made of stainless steel. The tabletop of the isolation table (2) is a three-layer sandwich honeycomb structure. The upper surface of the tabletop is subjected to a Midi pattern matte treatment, and a polymer composite damping rubber vibration isolation pad is provided at the bottom of the tabletop; the amplitude of the isolation table (2) is less than 4um, and the flatness is 0.02 - 0.05mm / m 2 .

3. The high-precision deformation measurement method of the balance based on binocular vision according to claim 2, wherein The described balance bracket (3) includes a positioning block (33) and a balance horizontal support plate (8) connected in sequence from front to back, and the balance horizontal support plate (8) is connected to the balance roll angle adjustment block (4); The positioning block (33) is provided with a plurality of threaded holes I (13) corresponding to the screw holes on the tabletop of the seismic isolation table (2). The positioning block (33) is fixed by bolts that penetrate the threaded holes I (13) from top to bottom and insert into the screw holes on the tabletop of the seismic isolation table (2). The balance roll angle adjustment block (4) is provided with a plurality of threaded holes VI (32) corresponding to the screw holes on the tabletop of the seismic isolation table (2). The balance roll angle adjustment block (4) is fixed by bolts that penetrate the threaded holes VI (32) from top to bottom and insert into the screw holes on the tabletop of the seismic isolation table (2). A fixing flange (12) is fixed on the rear end face of the balance adapter (9). A plurality of flange holes (11) are arranged circumferentially on the flange (12). The balance adapter (9) is fixed on the front end face of the balance roll angle adjustment block (4) by screws passing through the flange holes (11). A tapered hole (10) is provided on the front end face of the balance adapter (9). The tapered section at the rear end of the measured balance (1) is inserted into the tapered hole (10) for fixation. The balance roll angle adjustment block (4) adjusts the roll angle of the measured balance (1).

4. The high-precision deformation measurement method of the balance based on binocular vision according to claim 3, characterized in that The described lateral displacement table (5) is a horizontal square flat plate. The edge of the lateral displacement table (5) is provided with a plurality of threaded holes VII (34) corresponding to the screw holes on the tabletop of the seismic isolation table (2). The lateral displacement table (5) is fixed by bolts that penetrate the threaded holes VII (34) from top to bottom and insert into the screw holes on the tabletop of the seismic isolation table (2). A protruding lateral displacement table guide rail (15) is arranged on the horizontal central axis of the lateral displacement table (5). Sunken lateral displacement table card slots (36) are arranged on both sides of the lateral displacement table guide rail (15). The vertical displacement table (6) is a vertical square flat plate. Reinforcing ribs are provided on the back of the vertical displacement table (6). The edge of the vertical displacement table (6) is provided with a plurality of threaded holes II (17). The lower end of the vertical displacement table (6) is mounted on the lateral displacement table guide rail (15) and the lateral displacement table card slot (36) of the lateral displacement table (5) through a slider II (35). The vertical displacement table (6) moves back and forth along the lateral displacement table guide rail (15) and the lateral displacement table card slot (36) through the slider II (35), and is positioned and fixed by tightening the positioning bolts (14) that match the lateral displacement table card slot (36). The front of the vertical displacement table (6) faces the balance support (3). A protruding vertical displacement table guide rail (16) is arranged on the vertical central axis of the front of the vertical displacement table (6). Sunken vertical displacement table card slots (37) are arranged on both sides of the vertical displacement table guide rail (16). A slider I (18) is mounted on the vertical displacement table guide rail (16) and the vertical displacement table card slot (37). The slider I (18) moves up and down along the vertical displacement table guide rail (16) and the vertical displacement table card slot (37). Threaded holes III (20) are provided on the slider I (18), and the threaded holes III (20) correspond to the threaded holes II (17). The slider I (18) is assisted in fixation by tightening the positioning screws (19) that match the vertical displacement table card slot (37).

5. The high-precision deformation measurement method of the balance based on binocular vision according to claim 4, characterized in that The described binocular vision camera system (7) is fixedly installed through an L-shaped binocular vision camera support (21). The vertical plate of the binocular vision camera bracket (21) matches the front end face of the slider I (18). Threaded hole IV (22) is provided on the vertical plate. Threaded hole IV (22) matches threaded hole III (20) on the slider I (18). The binocular vision camera bracket (21) is fixed by a bolt assembly passing through threaded hole IV (22), threaded hole III (20) and threaded hole II (17). The front end of the horizontal plate of the L-shaped binocular vision camera bracket (21) is connected to the camera bracket telescopic connecting plate (30) by means of fixing with track clamping screws; the lower surface of the front end of the camera bracket telescopic connecting plate (30) is connected to the cross beam (31) by means of fixing with track clamping screws; the cross beam (31) is parallel to the balance to be measured (1). The front end face of the cross beam (31) is fixed with the camera bracket front mounting plate (28). A number of threaded holes V (27) are provided on the camera bracket front mounting plate (28). The right camera (25) and the left camera (26) are fixed on the cross beam (31) by screws screwed into the threaded holes V (27). A strip light source (23) is provided on the central axis of the lower surface of the cross beam (31). A data acquisition module (24) is provided on the upper surface of the cross beam (31). The right camera (25) and the left camera (26) are respectively connected to the data acquisition module (24) by cables. The data acquisition module (24) is connected to the computer (29) by a cable; the images captured by the right camera (25) and the left camera (26) are transmitted to the computer (29) through the data acquisition module (24). The binocular vision camera system (7) moves forward and backward through the slider II (35), moves up and down through the slider I (18), and moves left and right through the camera bracket telescopic connecting plate (30); the forward and backward movement is supplemented by the cross beam (31), and the left and right movement is supplemented by the camera bracket telescopic connecting plate (30).

6. The high-precision deformation measurement method of the balance based on binocular vision according to claim 5, characterized in that The gradient amplitude mean method described above includes the following steps: S31. Calculate the gradient magnitude along the gradient direction at the roughly located edge points ; S32. Determine the value range of the fine positioning edge points that satisfy the gradient magnitude below a preset threshold ; S33. Take the gradient components and as weights, and according to the following sub-pixel correction formula for the edge position along the gradient direction, obtain the position of the accurately located edge point: ； Among them, and are the distance components of a pixel point along the gradient direction from the roughly located edge point; and are the gradient components of a pixel point along the gradient direction from the roughly located edge point; is the number of pixel points along the gradient direction; is x the sub-pixel variable value of the edge position along the gradient direction, is y the sub-pixel variable value of the edge position along the gradient direction; Let the roughly located edge point be , the gradient direction be , then when , the next two points for calculating the gradient magnitude along the gradient direction are and , where , .

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