A low-temperature balance calibration device for simulating test states and its calibration method

Abstract

The present invention belongs to the technical field of wind tunnel test, and discloses a low-temperature balance calibration device for simulating test states and a calibration method thereof. The base connection block of the calibration device is fixed on the lower wall plate of the low-temperature oven; an L-shaped base, a lower support block and an upper support block are sequentially stacked on the base connection block; an integral strut low-temperature balance is fixed on the vertical plate of the base; the loading head is of a wing-shaped symmetric structure, a slide rail is arranged on the upper surface, a slider is installed on the slide rail, and the slider is sleeved on the front end of the low-temperature balance; the loading head moves back and forth along the slide rail until the loading center coincides with the calibration center of the low-temperature balance; symmetrically arranged arms are arranged around the loading head, a tip is fixed on the upper surface of the arm, a pull frame is hung on the tip, and the pull frame is connected to a code disk. The calibration method includes installing the low-temperature balance, the loading head, the code disk and calibrating the low-temperature balance. The calibration device and method fix the balance and the support device in the low-temperature oven, and perform loading and data measurement outside the low-temperature oven, improving the calibration efficiency and calibration accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind tunnel testing, and particularly relates to a low-temperature balance calibration device for simulating test conditions and a calibration method thereof. Background Art

[0002] In a low-temperature test environment, the accurate measurement of a balance is crucial for test results. However, the low-temperature environment poses special challenges to the calibration of the balance. The existing technical method is to install a fixed calibration device in a low-temperature oven and drive a standard weight through a motor system to achieve the calibration of the balance in a low-temperature environment. Its disadvantages are as follows: The driving mechanism and the loading arm occupy a large space, making installation and use difficult; The motor system is prone to performance degradation or failure in a low-temperature environment, affecting the calibration stability; The change in the coefficient of thermal expansion of materials in a low-temperature environment will cause a slight change in the mass of the standard weight, reducing the calibration accuracy.

[0003] Currently, there is an urgent need to develop a low-temperature balance calibration device for simulating test conditions and a calibration method thereof. Summary of the Invention

[0004] One technical problem to be solved by the present invention is to provide a low-temperature balance calibration device for simulating test conditions, and another technical problem to be solved by the present invention is to provide a calibration method for a low-temperature balance for simulating test conditions to overcome the defects of the prior art.

[0005] The base connection block of the low-temperature balance calibration device for simulating test conditions of the present invention is fixed on the lower wall plate of the low-temperature oven; The upper surface of the base connection block is successively stacked with a base, a lower support block, and an upper support block from bottom to top;

[0006] The base is L-shaped; The horizontal plate of the base is in surface fit with the base connection block, positioned by the guide rail on the base connection block, and fixedly connected by a bolt assembly; The horizontal plate of the base and the lower support block, and between the lower support block and the upper support block are all in surface fit and fixedly connected by bolt assemblies; The vertical plate of the base is in column fit with the support rod at the rear end of the low-temperature balance, and the support rod is tightened and fixed by a bolt assembly; The top surface of the upper support block is provided with a cylindrical groove matching the column section of the support rod of the low-temperature balance, and the upper support block supports the support rod;

[0007] The loading head adopts an airfoil symmetric structure, and an installation platform is provided at the center of the upper surface of the loading head. A slide rail is provided on the installation platform, and a slider is installed on the slide rail. The slider is sleeved on the square column at the front end of the low-temperature balance through a square hole; The slider and the loading head move relative to each other back and forth through the slide rail. When the loading center of the loading head coincides with the calibration center of the low-temperature balance, the slider is positioned and fixedly connected to the installation platform by a bolt assembly; Four centrally symmetrically distributed support arms are provided around the loading head, and one tip is fixed on the upper surface of each support arm;

[0008] A corresponding pulling frame is mounted on each tip, and the pulling frame is a rectangular frame; a socket is fixed in the central pin hole on the lower surface of the inner frame of the pulling frame, and the socket matches the tip; in the central threaded hole on the lower surface of the outer frame of the pulling frame, an upper pull rod is fixed through internal threads, and the lower end of the upper pull rod passes through a through hole provided on the lower wall plate of the low-temperature oven; after passing through, a pull rod connecting nut, a lower pull rod and a code disc are sequentially fixed to the lower end of the upper pull rod through threads.

[0009] Further, the lowest temperature of the low temperature is -160 °C.

[0010] Further, a fillet transition is adopted between the vertical plate and the horizontal plate of the base to reduce stress concentration and avoid deformation and tearing of the base caused by excessive load.

[0011] Further, the upper support block is close to the low-temperature balance.

[0012] Further, the nut block is a trapezoidal nut block, and a threaded hole is opened in the center of the nut block, and the threaded hole matches the screw of the screw assembly.

[0013] Further, a guide rail parallel to the central axis of the low-temperature balance is provided on the upper surface of the base connecting block, and parallel T-shaped grooves are provided on both the left and right sides of the guide rail; the horizontal plate of the base is mounted on the guide rail and moves back and forth along the guide rail to adjust the position of the upper pull rod to ensure that the upper pull rod passes through the center of the corresponding through hole and penetrates the lower wall plate of the low-temperature oven; the base is fixed to the base connecting block through a nut block and a screw assembly placed in the T-shaped groove.

[0014] Further, the inner diameter of the code disc is determined according to the diameter of the standard weights used, which is convenient for loading and taking the standard weights.

[0015] Further, the upper section of the tip is conical and the lower section is cylindrical, and there is a smooth transition between the upper and lower sections; the cylindrical surface of the cylinder is the mating surface between the tip and the loading head, which is used for the installation and positioning between the tip and the loading head; the socket is a stepped cylinder, the cylinder diameter of the upper section is smaller than that of the lower section, the cylinder diameter of the upper section is installed in the central pin hole on the lower surface of the inner frame of the pulling frame through cylinder fit, and a tapered hole is provided in the cylinder of the lower section; the apex angle of the tapered hole of the socket is greater than the apex angle of the cone of the tip, and there is a gap between the tapered hole and the cone, and the influence of cold shrinkage of the material caused by low temperature on the calibration data is reduced through the gap.

[0016] Further, a horizontal reference plane is provided on the upper surface of the vertical plate of the base for leveling the horizontal plate of the base; a horizontal reference plane is provided on the upper surface of the slider for leveling the roll angle of the low-temperature balance; the sizes of the horizontal reference planes match commercially available high-precision spirit levels.

[0017] The low-temperature balance calibration method for simulating the test state of the present invention includes the following steps:

[0018] S10. Install a low-temperature balance;

[0019] Fix the base connection block on the lower wall plate of the low-temperature oven;

[0020] Install the base on the upper surface of the base connection block through the nut block and bolt assembly;

[0021] Stack and fix the lower support block and the upper support block on the upper surface of the horizontal plate of the base in sequence from bottom to top through the bolt assembly;

[0022] Install the support rod at the rear end of the low-temperature balance to obtain a low-temperature balance assembly; place the support rod of the low-temperature balance assembly in the cylindrical groove of the upper support block, push it backward along the cylindrical groove, and install the support rod on the vertical plate of the base through bolts;

[0023] Connect the signal wire of the low-temperature balance to the power supply and data acquisition system through the opening on the rear end face of the low-temperature oven;

[0024] S20. Install the loading head;

[0025] Fix 1 center point on the upper surface of each support arm of the loading head;

[0026] Install the slider on the slide rail of the installation platform of the loading head to obtain a loading head assembly;

[0027] Set the loading head assembly on the square column at the front end of the low-temperature balance through the square hole of the slider;

[0028] Move the loading head back and forth through the slide rail until the loading center of the loading head coincides with the centering of the low-temperature balance, and fix the slider on the loading head through the bolt assembly;

[0029] At the front end of the low-temperature balance, tighten the low-temperature balance through the gasket and the tensioning bolt to fix the low-temperature balance assembly;

[0030] Adjust the bolt assemblies between the base connection block, the base, the lower support block and the upper support block through the precision spirit level placed on the horizontal reference plane of the base and the precision spirit level placed on the horizontal reference plane of the slider to make the 2 horizontal reference planes level, and at the same time make the upper support block support the support rod;

[0031] S30. Install the code disc;

[0032] Install the top socket in the center pin hole on the lower surface of the inner frame of the pull frame through the cylinder in the upper section to obtain a pull frame assembly; then place the 4 pull frame assemblies on the 4 center points of the loading head respectively;

[0033] Pass the 4 upper pull rods through the 4 through holes on the lower wall plate of the low-temperature oven into the low-temperature oven, and connect and fix them to the center threaded holes on the lower surface of the corresponding outer frame of the pull frame through bolts;

[0034] At the lower end of each upper pull rod, a pull rod connecting nut, a lower pull rod and a code disc are sequentially fixed by threads;

[0035] S40. Calibrate the cryogenic balance;

[0036] It includes the following steps:

[0037] S41. Set the calibration temperature sequence;

[0038] S42. Close the cryogenic oven, adjust the temperature inside the cryogenic oven to the temperature values set in the calibration temperature sequence in turn, and maintain for 30 minutes. Load weights in the code disc, and according to the calibration process, perform loading and data acquisition on the lift direction, pitch direction and roll direction of the cryogenic balance in turn. Finally, calculate the output of each direction and the corresponding interference amount;

[0039] S43. Adjust the temperature of the cryogenic oven to room temperature and maintain for 30 minutes, then open the cryogenic oven; Remove the pull rod connecting nut, the lower pull rod and the code disc; Remove the upper pull rod; Remove the pull box from the loading head; Remove the gasket and the tension bolt at the front end of the cryogenic balance; Rotate the cryogenic balance 90° along the central axis of the balance, and then fix it with the gasket and the tension bolt; Repeat S20~S30;

[0040] S44. Repeat S42 to complete the loading and data acquisition of the side force direction and yaw direction of the cryogenic balance, and finally calculate the output of each direction and the corresponding interference amount to complete the calibration;

[0041] S45. Adjust the temperature of the cryogenic oven to room temperature and maintain for 30 minutes, and remove the cryogenic balance calibration device.

[0042] In the cryogenic balance calibration device simulating the test state of the present invention, the upper support block is close to the cryogenic balance, which can effectively share the deformation of the support rod during the loading process, reduce the bending deformation of the support rod, ensure that the transmission of the loading force is more accurate and stable, and reduce the data jump of the cryogenic balance caused by the deformation of the support rod due to the loaded weights.

[0043] In the cryogenic balance calibration device simulating the test state of the present invention, both between the base and the lower support block and between the upper support block and the lower support block are connected by bolt positioning, which avoids the movement of each support block or the inconsistent support positions after disassembly and assembly due to shaking during the loading process, affecting the quality of the calibration data.

[0044] The loading head in the low-temperature balance calibration device for simulating test states of the present invention adopts an airfoil symmetric structure, which can evenly distribute the loading force, realize the mechanical decomposition of force and torque, reduce the errors caused by asymmetric loading, and improve the calibration accuracy and stability. At the same time, loading 4 code discs can realize the calibration of force and torque in the positive and negative directions of the lift direction; after removing the low-temperature balance and reinstalling it after rotating it 90 degrees, the calibration of force and torque in the positive and negative directions of the side force direction can be realized.

[0045] The low-temperature balance calibration device for simulating test states of the present invention stably installs the balance in the low-temperature oven through a fixed base, abandons the complex driving mechanism, reduces the space occupied by the device, avoids interference and improves stability; the standard weights are loaded and data are measured outside the low-temperature oven, which avoids frequently opening the oven door, reduces the temperature fluctuation, and ensures the stability of the test environment and the safety of personnel; the fixed base and the loading device adopt low-temperature adaptable materials to ensure long-term stability in the low-temperature environmental chamber and avoid performance degradation caused by temperature changes. The low-temperature balance calibration method for simulating test states of the present invention ensures the continuity and reliability of the calibration data through real-time calibration; simplifies the operation process through external loading and measurement, reduces the difficulty and errors of manual operation, and improves the calibration efficiency; ensures a high degree of consistency between the calibration process and the test environment by simulating the actual low-temperature test conditions, and significantly improves the calibration accuracy.

[0046] In short, the low-temperature balance calibration device and its calibration method for simulating test states of the present invention have low-temperature adaptability. By simplifying the structure, the fixed base in the low-temperature oven is used to fix the balance and the support device, and real-time calibration is achieved by performing loading and data measurement outside the low-temperature oven, improving the calibration efficiency and calibration accuracy; it provides a technical solution with high precision, high efficiency, and high reliability for the balance calibration in the low-temperature test environment, and provides technical support for the research on the influence of temperature on the balance in the hypersonic wind tunnel test. Description of the Drawings

[0047] Figure 1 It is the overall assembly drawing of the low-temperature balance calibration device for simulating test states;

[0048] Figure 2a It is the assembly schematic diagram (front view) of the low-temperature balance in the low-temperature balance calibration device for simulating test states;

[0049] Figure 2b It is the assembly schematic diagram (side view) of the low-temperature balance in the low-temperature balance calibration device for simulating test states;

[0050] Figure 3 It is the assembly schematic diagram of the loading head in the low-temperature balance calibration device for simulating test states;

[0051] Figure 4Schematic assembly diagram of the weight mounting device in the low-temperature balance calibration device in the simulated test state.

[0052] In the figure, 1 - low-temperature oven; 2 - low-temperature balance; 3 - base; 4 - upper support block; 5 - lower support block; 6 - nut block; 7 - base connection block; 8 - code disk; 9 - lower pull rod; 10 - pull rod connection nut; 11 - upper pull rod; 12 - center point; 13 - loading head; 14 - slider; 15 - pull frame; 16 - socket. Specific implementation mode

[0053] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0054] Embodiment: As Figure 1 、 Figure 2a 、 Figure 2b 、 Figure 3 、 Figure 4 shown, the base connection block 7 of the low-temperature balance calibration device in the simulated test state of this embodiment is fixed on the lower wall plate of the low-temperature oven 1; the upper surface of the base connection block 7 is successively stacked with the base 3, the lower support block 5 and the upper support block 4 from bottom to top;

[0055] The base 3 is L-shaped; the horizontal plate of the base 3 is in surface fit with the base connection block 7, positioned by the guide rail on the base connection block 7 and fixedly connected by a bolt assembly; the horizontal plate of the base 3 is in surface fit with the lower support block 5, and the lower support block 5 is in surface fit with the upper support block 4, and both are fixedly connected by bolt assemblies; the vertical plate of the base 3 is in column fit with the support rod at the rear end of the low-temperature balance 2, and the support rod is tightened and fixed by a bolt assembly; the top surface of the upper support block 4 is provided with a cylindrical groove matching the column section of the support rod of the low-temperature balance, and the upper support block 4 supports the support rod;

[0056] The loading head 13 adopts a wing-shaped symmetric structure. The center of the upper surface of the loading head 13 is provided with a mounting platform, and a slide rail is arranged on the mounting platform. The slider 14 is installed on the slide rail, and the slider 14 is sleeved on the square column at the front end of the low-temperature balance 2 through a square hole; the slider 14 and the loading head 13 move relative to each other back and forth through the slide rail. When the loading center of the loading head 13 coincides with the calibration center of the low-temperature balance 2, the slider 14 is positioned and fixedly connected to the mounting platform by a bolt assembly; four centrally symmetrically distributed support arms are arranged around the loading head 13, and one center point 12 is fixed on the upper surface of each support arm;

[0057] A corresponding pulling frame 15 is mounted on each top end 12. The pulling frame 15 is a rectangular frame body. A socket 16 is fixed in the central pin hole on the lower surface of the inner frame of the pulling frame 15. The socket 16 is matched with the top end 12. In the central threaded hole on the lower surface of the outer frame of the pulling frame 15, an upper pull rod 11 is fixed by internal threads. The lower end of the upper pull rod 11 passes through a through hole provided on the lower wall plate of the low-temperature oven 1. After passing through, a pull rod connection nut 10, a lower pull rod 9 and a code disc 8 are sequentially fixed to the lower end of the upper pull rod 11 by threads.

[0058] Further, the lowest temperature of the low temperature is -160 °C.

[0059] Further, a fillet transition is adopted between the vertical plate and the horizontal plate of the base 3 to reduce stress concentration and avoid deformation and tearing of the base 3 caused by excessive load.

[0060] Further, the upper support block 4 is close to the low-temperature balance 2.

[0061] Further, the nut block 6 is a trapezoidal nut block, and a threaded hole is opened in the center of the nut block 6. The threaded hole is matched with the screw of the screw assembly.

[0062] Further, a guide rail parallel to the central axis of the low-temperature balance 2 is provided on the upper surface of the base connection block 7. Parallel T-shaped grooves are provided on both the left and right sides of the guide rail. The horizontal plate of the base 3 is mounted on the guide rail and moves back and forth along the guide rail to adjust the position of the upper pull rod 11 to ensure that the upper pull rod 11 passes through the center of the corresponding through hole and penetrates the lower wall plate of the low-temperature oven 1. The base 3 is fixed to the base connection block 7 by a nut block 6 and a screw assembly placed in the T-shaped groove.

[0063] Further, the inner diameter of the code disc 8 is determined according to the diameter of the standard weight used, which is convenient for loading and taking the standard weight.

[0064] Further, the upper section of the top end 12 is a cone, and the lower section is a cylinder. A smooth transition is provided between the upper section and the lower section. The cylindrical surface of the cylinder is the mating surface between the top end 12 and the loading head 13, which is used for the installation and positioning between the top end 12 and the loading head 13. The socket 16 is a stepped cylinder. The cylinder diameter of the upper section is smaller than that of the lower section. The cylinder diameter of the upper section is installed in the central pin hole on the lower surface of the inner frame of the pulling frame 15 by cylindrical fit. A tapered hole is provided in the cylinder of the lower section. The apex angle of the tapered hole of the socket 16 is greater than the apex angle of the cone of the top end 12. A gap is provided between the tapered hole and the cone. The influence of cold shrinkage of materials caused by low temperature on the calibration data is reduced through the gap.

[0065] Further, a horizontal reference plane is provided on the upper surface of the vertical plate of the base 3 for leveling the horizontal plate of the base 3; a horizontal reference plane is provided on the upper surface of the slider 14 for leveling the roll angle of the cryogenic balance 2; the sizes of the horizontal reference planes match commercially available high-precision spirit levels.

[0066] The cryogenic balance calibration method in the simulated test state of this embodiment includes the following steps:

[0067] S10. Install the cryogenic balance 2;

[0068] Fix the base connecting block 7 on the lower wall plate of the cryogenic oven 1;

[0069] Install the base 3 on the upper surface of the base connecting block 7 through the nut block 6 and the bolt assembly;

[0070] Stack and fix the lower support block 5 and the upper support block 4 on the upper surface of the horizontal plate of the base 3 in sequence from bottom to top through the bolt assembly;

[0071] Install the support rod at the rear end of the cryogenic balance 2 to obtain a cryogenic balance assembly; place the support rod of the cryogenic balance assembly in the cylindrical groove of the upper support block 4, push it backward along the cylindrical groove, and install the support rod on the vertical plate of the base 3 through bolts;

[0072] Connect the signal line of the cryogenic balance 2 to the power supply and the data acquisition system through the opening on the rear end face of the cryogenic oven 1;

[0073] S20. Install the loading head 13;

[0074] Fix 1 center point 12 on the upper surface of each arm of the loading head 13;

[0075] Install the slider 14 on the slide rail of the installation platform of the loading head 13 to obtain a loading head assembly;

[0076] Set the loading head assembly on the square column at the front end of the cryogenic balance 2 through the square hole of the slider 14;

[0077] Move the loading head 13 back and forth through the slide rail until the loading center of the loading head 13 coincides with the centering of the cryogenic balance 2, and fix the slider 14 on the loading head 13 through the bolt assembly;

[0078] At the front end of the cryogenic balance 2, tighten the cryogenic balance 2 through the gasket and the tensioning bolt to fix the cryogenic balance assembly;

[0079] Adjust the bolt assemblies between the components of the base connecting block 7, the base 3, the lower support block 5 and the upper support block 4 through the precision spirit level placed on the horizontal reference plane of the base 3 and the precision spirit level placed on the horizontal reference plane of the slider 14 to make the 2 horizontal reference planes horizontal, and at the same time make the upper support block 4 support the support rod;

[0080] S30. Install the code disk 8;

[0081] Install the top socket 16 through the cylinder in the upper section into the central pin hole on the lower surface of the inner frame of the tension frame 15 to obtain the tension frame assembly; then place the 4 tension frame assemblies on the 4 center points 12 of the loading head 13 respectively;

[0082] Pass the 4 upper pull rods 11 through the 4 through holes in the lower wall plate of the low-temperature oven 1 into the low-temperature oven 1 respectively, and fix them by bolt connection to the central threaded holes on the lower surface of the outer frame of the corresponding tension frame 15;

[0083] Fix the tension rod connection nut 10, the lower pull rod 9 and the code disk 8 in sequence by threads at the lower end of each upper pull rod 11;

[0084] S40. Calibrate the low-temperature balance 2;

[0085] It includes the following steps:

[0086] S41. Set the calibration temperature sequence;

[0087] S42. Close the low-temperature oven 1, adjust the temperature in the low-temperature oven 1 to the temperature values set in the calibration temperature sequence in sequence, and maintain for 30 minutes. Load weights in the code disk 8, and according to the calibration process, perform loading and data acquisition on the lift direction, pitch direction and roll direction of the low-temperature balance 2 in sequence. Finally, calculate the output of each direction and the corresponding interference amount;

[0088] S43. Adjust the temperature of the low-temperature oven 1 to normal temperature and maintain for 30 minutes, then open the low-temperature oven 1; Remove the tension rod connection nut 10, the lower pull rod 9 and the code disk 8; Remove the upper pull rod 11; Remove the tension frame 15 from the loading head 13; Remove the gasket and the tension bolt at the front end of the low-temperature balance 2; Rotate the low-temperature balance 2 by 90° along the balance central axis, and then fix it with the gasket and the tension bolt; Repeat S20~S30;

[0089] S44. Repeat S42 to complete the loading and data acquisition of the side force direction and yaw direction of the low-temperature balance 2, and finally calculate the output of each direction and the corresponding interference amount to complete the calibration;

[0090] S45. Adjust the temperature of the low-temperature oven 1 to normal temperature and maintain for 30 minutes, and remove the low-temperature balance calibration device.

[0091] In this embodiment, the length of the upper pull rod 11 is 400mm, and the length of the lower pull rod 9 is 300mm. The nut block 6 has a limiting function and has a threaded hole of M10 in the center; The 4 center points 12 are distributed in a square, and the distance between adjacent center points 12 is 300mm.

[0092] The low-temperature balance calibration device in the simulation test state of this embodiment can be calibrated at normal temperature, 0°C, -40°C, -80°C, -120°C, and -160°C, and the outputs and interferences of forces and torques in different directions of the low-temperature balance under 6 different temperature states are obtained. The obtained low-temperature balance calibration data shows that different temperatures do have an impact on the outputs of each element of the low-temperature balance, and moreover, as the temperature decreases, the outputs of each element of the low-temperature balance gradually increase, providing data support for subsequent low-temperature balance calibration.

[0093] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. For those familiar with the art, without departing from the principle of the present invention, all the features disclosed in the present invention, or all the steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any way. The present invention is not limited to the specific details and the illustrated examples here.

Claims

1. A low-temperature balance calibration device for simulating test states, characterized in that, The base connection block (7) of the described low-temperature balance calibration device is fixed on the lower wall plate of the low-temperature oven (1); the upper surface of the base connection block (7) is successively stacked with the base (3), the lower support block (5), and the upper support block (4) from bottom to top; The base (3) is L-shaped; the horizontal plate of the base (3) is in surface fit with the base connection block (7), positioned by the guide rail on the base connection block (7), and fixedly connected by a bolt assembly; the horizontal plate of the base (3) is in surface fit with the lower support block (5), and the lower support block (5) is in surface fit with the upper support block (4), both are fixedly connected by bolt assemblies; the vertical plate of the base (3) is in column fit with the support rod at the rear end of the low-temperature balance (2), and the support rod is tightened and fixed by a bolt assembly; the top surface of the upper support block (4) is provided with a cylindrical groove matching the column section of the support rod of the low-temperature balance, and the upper support block (4) supports the support rod; The loading head (13) adopts an airfoil symmetric structure, and an installation platform is provided at the center of the upper surface of the loading head (13). A slide rail is provided on the installation platform, and the slider (14) is installed on the slide rail. The slider (14) is sleeved on the square column at the front end of the low-temperature balance (2) through a square hole; the slider (14) and the loading head (13) move relative to each other back and forth through the slide rail. When the loading center of the loading head (13) coincides with the calibration center of the low-temperature balance (2), the slider (14) is positioned and fixedly connected to the installation platform by a bolt assembly; four centrally symmetrically distributed support arms are provided around the loading head (13), and one center tip (12) is fixed on the upper surface of each support arm; A corresponding pull frame (15) is hung on each center tip (12), and the pull frame (15) is a rectangular frame; a top socket (16) is fixed in the center pin hole on the lower surface of the inner frame of the pull frame (15), and the top socket (16) matches the center tip (12); in the center threaded hole on the lower surface of the outer frame of the pull frame (15), an upper pull rod (11) is fixed by internal threads, and the lower end of the upper pull rod (11) passes through the through hole provided on the lower wall plate of the low-temperature oven (1); after passing through, a pull rod connection nut (10), a lower pull rod (9), and a code disk (8) are successively fixed by threads at the lower end of the upper pull rod (11).

2. The cryogenic balance calibration device for simulating test states according to claim 1, characterized in that, The lowest temperature of the described low temperature is -160 °C.

3. The cryogenic balance calibration device for simulating test states according to claim 1, wherein, The vertical plate and the horizontal plate of the described base (3) adopt a fillet transition to reduce stress concentration and avoid deformation and tearing of the base (3) caused by excessive load.

4. The cryogenic balance calibration device for simulating test states according to claim 1, characterized in that, The described upper support block (4) is close to the low-temperature balance (2).

5. The cryogenic balance calibration device for simulating test states according to claim 1, wherein The upper surface of the described base connection block (7) is provided with a guide rail parallel to the central axis of the low-temperature balance (2), and parallel T-shaped grooves are provided on both the left and right sides of the guide rail; the horizontal plate of the base (3) is installed on the guide rail and moves back and forth along the guide rail to adjust the position of the upper pull rod (11) to ensure that the upper pull rod (11) passes through the center of the corresponding through hole and penetrates the lower wall plate of the low-temperature oven (1); the base (3) is fixed on the base connection block (7) by a nut block (6) placed in the T-shaped groove and a screw assembly.

6. The low-temperature balance calibration device for simulating test states according to claim 5, characterized in that, The described nut block (6) is a trapezoidal nut block, and a threaded hole is opened in the center of the nut block (6), and the threaded hole matches the screw of the screw assembly.

7. The cryogenic balance calibration device for simulating test states according to claim 1, characterized in that, The inner diameter of the code disc (8) is determined according to the diameter of the standard weights used, which facilitates the loading and taking of the standard weights.

8. The cryogenic balance calibration device for simulating test states according to claim 1, wherein The upper part of the center point (12) is a cone, and the lower part is a cylinder, with a smooth transition between the upper and lower parts; the cylindrical surface of the cylinder is the mating surface between the center point (12) and the loading head (13), which is used for the installation and positioning between the center point (12) and the loading head (13); the socket (16) is a stepped cylinder, the diameter of the upper cylinder is smaller than that of the lower cylinder, the diameter of the upper cylinder is installed in the center pin hole on the lower surface of the inner frame of the pulling frame (15) through column fitting, and a tapered hole is arranged in the lower cylinder; the apex angle of the tapered hole of the socket (16) is larger than the apex angle of the cone of the center point (12), and a gap is arranged between the tapered hole and the cone, and the influence of the cold shrinkage of the material caused by low temperature on the calibration data is reduced through the gap.

9. The cryogenic balance calibration device for simulating test states according to claim 1, characterized in that, The upper surface of the vertical plate of the base (3) is provided with a horizontal reference plane for leveling the horizontal plate of the base (3); the upper surface of the slider (14) is provided with a horizontal reference plane for leveling the roll angle of the cryogenic balance (2); the sizes of the horizontal reference planes all match the commercially available high-precision spirit levels.

10. A low-temperature balance calibration method for simulating test states, which is used for the low-temperature balance calibration device for simulating test states according to any one of claims 1 to 9, characterized in that, The cryogenic balance calibration method includes the following steps: S10. Install the cryogenic balance (2); Fix the base connecting block (7) on the lower wall plate of the cryogenic oven (1); Install the base (3) on the upper surface of the base connecting block (7) through the nut block (6) and the bolt assembly; Stack and fix the lower support block (5) and the upper support block (4) on the upper surface of the horizontal plate of the base (3) in sequence from bottom to top through the bolt assembly; Install the support rod at the rear end of the cryogenic balance (2) to obtain a cryogenic balance assembly; place the support rod of the cryogenic balance assembly in the cylindrical groove of the upper support block (4), push it backward along the cylindrical groove, and install the support rod on the vertical plate of the base (3) through bolts; Connect the signal line of the cryogenic balance (2) to the power supply and the data acquisition system through the opening on the rear end face of the cryogenic oven (1); S20. Install the loading head (13); Fix 1 center point (12) on the upper surface of each arm of the loading head (13); Install the slider (14) on the slide rail of the installation platform of the loading head (13) to obtain a loading head assembly; Set the loading head assembly on the square column at the front end of the cryogenic balance (2) through the square hole of the slider (14); Move the loading head (13) back and forth through the slide rail until the loading center of the loading head (13) coincides with the calibration center of the cryogenic balance (2), and fix the slider (14) on the loading head (13) through the bolt assembly; At the front end of the cryogenic balance (2), tighten the cryogenic balance (2) through the gasket and the tensioning bolt to fix the cryogenic balance assembly; Adjust the bolt assemblies between the base connecting block (7), the base (3), the lower support block (5) and the upper support block (4) through the precision spirit level placed on the horizontal reference plane of the base (3) and the precision spirit level placed on the horizontal reference plane of the slider (14) to make the 2 horizontal reference planes horizontal, and at the same time make the upper support block (4) support the support rod; S30. Install the code disc (8); Install the top socket (16) into the central pin hole on the lower surface of the inner frame of the pulling frame (15) through the cylinder in the upper section to obtain the pulling frame assembly; then place the 4 pulling frame assemblies on the 4 tips (12) of the loading head (13) respectively; Pass the 4 upper pull rods (11) through the 4 through holes in the lower wall plate of the low-temperature oven (1) into the low-temperature oven (1) respectively, and fix them in the central threaded holes on the lower surface of the corresponding outer frame of the pulling frame (15) by bolt connection; Fix the pull rod connection nut (10), the lower pull rod (9) and the code disc (8) on the lower end of each upper pull rod (11) in sequence by threads; S40. Calibrate the low-temperature balance (2); It includes the following steps: S41. Set the calibration temperature sequence; S42. Close the low-temperature oven (1), adjust the temperature in the low-temperature oven (1) to the temperature values set in the calibration temperature sequence in sequence, and maintain for 30 minutes. Load weights in the code disc (8), and according to the calibration process, perform loading and data acquisition on the lift direction, pitch direction and roll direction of the low-temperature balance (2) in sequence. Finally, calculate the output in each direction and the corresponding interference amount; S43. Adjust the temperature of the low-temperature oven (1) to normal temperature and maintain for 30 minutes, then open the low-temperature oven (1); Remove the pull rod connection nut (10), the lower pull rod (9) and the code disc (8); Remove the upper pull rod (11); Remove the pulling frame (15) from the loading head (13); Remove the gasket and the tension bolt at the front end of the low-temperature balance (2); Rotate the low-temperature balance (2) 90° along the balance central axis, and then fix it with the gasket and the tension bolt; Repeat S20~S30; S44. Repeat S42 to complete the loading and data acquisition of the side force direction and yaw direction of the low-temperature balance (2), and finally calculate the output in each direction and the corresponding interference amount to complete the calibration; S45. Adjust the temperature of the low-temperature oven (1) to normal temperature and maintain for 30 minutes, and remove the low-temperature balance calibration device.

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