Swing arm node rigidity test fixture

Abstract

The present application relates to the technical field of mechanical performance test, and discloses a test tool for the rigidity of a rotating arm joint, which comprises a clamping assembly for clamping and fixing a measured object, and a camera device for collecting images.The tool further comprises a circular path moving assembly and a lifting path assembly, and the circular path moving assembly and the lifting path assembly are cooperatively linked to drive the camera device to perform a composite scanning movement of a preset track around the measured object.Through the linkage scanning mode, the system can obtain a complete panoramic three-dimensional surface digital model of the measured object before and after the load is applied.The complete surface model provides a sufficient data basis for subsequent full-field displacement analysis, so that the system can accurately separate the pure elastic deformation displacement component from the total displacement field containing the rigid body displacement, and solve the technical problem that the rigid body displacement separation is inaccurate and the accuracy of the rigidity test result is affected due to incomplete measurement data.

Description

Technical Field

[0001] This invention relates to the field of mechanical performance testing technology, specifically to a tooling for testing the stiffness of a swing arm node. Background Technology

[0002] As a core component in critical mechanical structures such as vehicle suspension systems, the stiffness characteristics of the swingarm joint are a fundamental technical indicator determining the overall handling stability, reliability, and safety of the vehicle. Therefore, accurate measurement of the swingarm joint's stiffness is a necessary step in product development, quality control, and performance verification processes.

[0003] In existing stiffness testing techniques, a common method is to use contact displacement sensors. This method involves placing one or more sensors at specific locations on the object under test, applying a known load through a loading device, and measuring the displacement at those locations. The stiffness is then calculated based on the force-displacement relationship. However, this method only reflects the displacement information of a single or a few discrete measurement points, failing to capture the complete deformation distribution of the object under load. More importantly, during loading, in addition to its own elastic deformation, the object often undergoes minute overall translational or rotational displacements within the fixture—i.e., rigid body displacements. The displacement measured by contact sensors is a coupled value of elastic deformation displacement and rigid body displacement, unable to effectively separate the two. This leads to a deviation between the calculated stiffness value and the true stiffness characteristics of the object under test.

[0004] To obtain full-field deformation information, optical non-contact measurement techniques such as 3D digital image correlation have been introduced into stiffness testing. This technique uses a fixed binocular vision system to capture surface images of the object before and after loading, reconstructing its 3D morphology and calculating the full-field displacement. However, due to the limitations of the measurement system's field of view, only local surface data of the object facing the camera can be obtained, while the morphology and displacement information of the back, sides, and other occluded areas are completely missing. When using this incomplete surface displacement data to solve for the overall rigid body displacement parameters of the object, the mathematical model used for calculation lacks sufficient geometric constraints, making it difficult to obtain a unique and accurate solution. This uncertainty in the rigid body displacement calculation directly hinders the accurate extraction of the purely elastic deformation component from the total displacement field, thus affecting the accuracy of the final stiffness calculation results. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a swing arm node stiffness testing fixture, which solves the problem that existing technologies, due to their use of single-point contact measurement or fixed-viewpoint local optical measurement, cannot obtain the complete surface displacement field of the object under test, thus failing to accurately separate rigid body displacement and elastic deformation, ultimately resulting in deviations in stiffness test results.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a rotating arm node stiffness testing fixture, including a path circular plate and a camera device, wherein an annular path moving component is provided inside the path circular plate, and a lifting path component is slidably connected to the inner side of the path circular plate, which, when combined, is used to drive the camera device to observe the object under test from multiple perspectives. A connecting base block is fixedly connected to the top side of the path circular plate. A radial length adjustment component is provided inside the connecting base block. Limiting components are provided on the inner sides of both ends of the radial length adjustment component. A fixing base block is fixedly connected to the other side of the connecting base block. A double clamping component is provided on the inner side of the fixing base block. A multi-directional clamping component is provided on the side of the fixing base block. The radial length adjustment assembly includes two first toothed blocks, both of which are slidably connected to the inner side of the connecting base block. A first drive motor is fixedly connected to the inner side of the connecting base block. A second gear is rotatably connected inside the connecting base block. The second gear is fixedly connected to the output end of the first drive motor and meshes with the sides of the two first toothed blocks. A first limiting slider is fixedly connected to the end of each of the two first toothed blocks. Both first limiting sliders are slidably connected to the inner side of the connecting base block. A first fixing block is fixedly connected to the side of each of the two first limiting sliders.

[0007] Preferably, the limiting component includes a limiting frame, which is slidably connected to the inner side of the first fixing block. Two second toothed blocks are slidably connected to the inner side of the limiting frame. A fifth gear is rotatably connected to the inner side of the first fixing block. The fifth gear is meshed with the sides of the two second toothed blocks. A fourth drive motor is fixedly connected to the side of the limiting frame. The fifth gear is fixedly connected to the output end of the fourth drive motor. Slide plates are fixedly connected to the side ends of the two second toothed blocks. A second limiting slider is slidably connected to the inner side of one end of the two slide plates. A slider plate is slidably connected to the inner side of the other end of the two slide plates. The slider plate is fixedly connected to the side of the second limiting slider. A second fixing block is fixedly connected to the inner side of the two slide plates.

[0008] Preferably, the annular path moving assembly includes an annular toothed plate, which is rotatably connected to the inner side of the path circular plate. A first gear is rotatably connected to the inner side of the path circular plate and meshes with the inner side of the annular toothed plate. A second driving assembly is fixedly connected to the side of the path circular plate, and the first gear is fixedly connected to the side of the second driving assembly. A protective shell is fixedly connected to the side of the path circular plate and is fixedly connected to the outer side of the second driving assembly. A second base block is fixedly connected to the side of the annular toothed plate, and a shell is fixedly connected to the side of the second base block.

[0009] Preferably, the lifting path assembly includes two fixed circular blocks, which are rotatably connected to the inner sides of both ends of the housing. A belt is fitted around the outer sides of the two fixed circular blocks. The camera device is fixedly connected to the side of the belt and slidably connected to the inner side of the housing. A third drive motor is fixedly connected to the side of the housing. One of the fixed circular blocks is fixedly connected to the output end of the third drive motor. The camera device is equipped with a scanning full-field deformation analysis stiffness testing system.

[0010] Preferably, the dual clamping assembly includes a third gear and a fourth gear, which are rotatably connected to the inner side of the fixed base block. A connecting rod is fixedly connected to the inner side of the third gear and the fourth gear. Multiple third toothed blocks are slidably connected to the inner side of the fixed base block. The third gear and the fourth gear are meshed with the sides of two of the third toothed blocks. Slide connecting blocks are fixedly connected to the ends of the multiple third toothed blocks. Third fixing blocks are fixedly connected to the sides of the multiple slide connecting blocks. Multiple anti-slip protrusions are fixedly connected to the sides of the third fixing blocks. A fifth driving assembly is fixedly connected to the inner side of the fixed base block. The connecting rod is fixedly connected to the output end of the fifth driving assembly.

[0011] Preferably, the multi-directional clamping assembly includes multiple fixing frames, each of which is fixedly connected to the side of the fixing base block. A fourth electric push rod is fixedly connected to the outer side of the end of each fixing frame, and an arc-shaped block is fixedly connected to the other end of each of the multiple fourth electric push rods.

[0012] Preferably, the fixed base block is provided with an axial stiffness fixture on its side, the axial stiffness fixture is provided with a second rotating arm node on its side, the top of the two first fixed blocks is provided with a first rotating arm node, two third electric push rods are fixedly connected to the inner side of each of the two first fixed blocks, the ends of the plurality of third electric push rods are respectively fixedly connected to the sides of the two limiting frames, a bracket top plate is fixedly connected to the side of the connecting base block, a first electric push rod and a second electric push rod are respectively fixedly connected to the side of the bracket top plate, an installation block is fixedly connected to the end of the first electric push rod, a radial stiffness fixture is threadedly connected inside the installation block, a pressure measuring block is fixedly connected to the bottom of the second electric push rod, and a plurality of first base blocks are fixedly connected to the bottom of the path circular plate.

[0013] Preferably, the overall working method of the swing arm node stiffness testing fixture includes the following steps: Before applying a load to the object under test, the ring path moving component and the lifting path component are linked to drive the camera device to scan the object under test in order to capture and establish an initial three-dimensional surface digital model of the object under test. A preset radial or axial load is applied to the object under test using the radial stiffness fixture or the axial stiffness fixture. Under load holding conditions, the annular path moving component and the lifting path component are controlled to work together again to drive the camera device to scan the deformed test object in order to capture and establish a digital model of the deformed three-dimensional surface of the test object after loading. The swing arm node stiffness testing fixture calculates the full-field three-dimensional displacement field data of the tested object by comparing and analyzing the initial three-dimensional surface digital model and the deformed three-dimensional surface digital model.

[0014] Preferably, the step of calculating the full-field three-dimensional displacement field data of the object under test further includes: Algorithm analysis is performed on the full-field three-dimensional displacement field data to identify and separate the rigid body displacement components caused by the overall translation, tilting or torsion of the measured object, and the purely elastic deformation displacement components caused only by the deformation of the measured object itself.

[0015] Preferably, the swing arm node stiffness testing fixture uses the purely elastic deformation displacement component obtained by separating the rigid body displacement component from the full-field three-dimensional displacement field data, combined with a preset loading force value, to calculate the most realistic stiffness characteristic value of the tested object.

[0016] This invention provides a fixture for testing the stiffness of a swing arm node. It has the following advantages: 1. This invention, by setting up a scanning full-field deformation analysis stiffness testing system and adopting an analysis method that compares the initial three-dimensional model with the deformed three-dimensional model, can accurately separate the rigid body displacement of the tested object caused by tilting, torsion, etc., and extract only the pure elastic deformation data for calculation. This fundamentally eliminates the error caused by the inability to identify complex motions in traditional single-point measurement, and improves the authenticity and accuracy of stiffness test results.

[0017] 2. This invention solves the problem of blind spots in traditional fixed vision measurement systems by setting up a ring path moving component and a lifting path component and making them work together to drive the camera device to perform multi-face scanning of the object under test. It can obtain almost complete full-surface deformation data of the object under test, providing the most comprehensive data foundation for high-precision separation of rigid body displacement and analysis of complex deformation modes.

[0018] 3. This invention integrates radial and axial loading fixtures, multi-directional clamping components, and a path scanning vision system into a single unit, achieving an automated process for automatic clamping, precise loading, and all-around scanning analysis of the object under test. It features a compact structure and convenient operation. Compared to the traditional method that requires manual placement of multiple sensors or repeated adjustments to the equipment position, it effectively improves overall testing efficiency and the consistency of results. Attached Figure Description

[0019] Figure 1 This is a front perspective view of the present invention; Figure 2 This is a perspective view of the rear side of the present invention; Figure 3 This is a schematic diagram of the radial stiffness test and axial stiffness test of the present invention; Figure 4 This is a schematic diagram of the circular path moving component of the present invention; Figure 5 This is a schematic diagram of the lifting path component of the present invention; Figure 6 This is a schematic diagram of the radial length adjustment component of the present invention; Figure 7 This is a schematic diagram of the external appearance of the limiting component of the present invention; Figure 8 This is a schematic diagram of the internal structure of the limiting component of the present invention; Figure 9 This is a schematic diagram of the radial stiffness tooling of the present invention; Figure 10 This is a schematic diagram of the axial stiffness test of the present invention; Figure 11 This is a schematic diagram of the dual clamping assembly of the present invention; Figure 12 This is a partial structural diagram of the dual clamping assembly of the present invention.

[0020] The components include: 1. Path circular plate; 2. First base block; 3. Connecting base block; 4. Support top plate; 5. Outer shell; 6. Second base block; 7. Protective shell; 8. First rotating arm node; 9. First electric push rod; 10. Second electric push rod; 11. Second rotating arm node; 12. Fixing frame; 13. First toothed block plate; 14. First drive motor; 15. First limiting slider; 16. First fixing block; 17. Radial stiffness fixture; 18. Mounting block; 19. Fixing base block; 20. Circular toothed plate; 21. First gear; 22. Camera equipment; 23. Second drive assembly; 24. Fixing circular block; 25. 1. Belt; 26. Third drive motor; 27. Second gear; 28. Limiting frame; 29. ​​Slide plate; 30. Sliding block; 31. Second fixing block; 32. Second limiting slider; 33. Second toothed block plate; 34. Fourth drive motor; 35. Third electric push rod; 36. Axial stiffness fixture; 37. Fourth electric push rod; 38. Arc block; 39. Anti-slip protrusion; 40. Fifth drive assembly; 41. Third gear; 42. Fourth gear; 43. Connecting rod; 44. Third toothed block plate; 45. Third fixing block; 46. Slide connecting block; 47. Fifth gear; 48. Pressure measuring block. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see the appendix Figure 1 - Appendix Figure 12 The present invention provides a rotating arm node stiffness testing fixture, including a path circular plate 1 and a camera device 22. The path circular plate 1 is provided with an annular path moving component, and a lifting path component is slidably connected to the inner side of the path circular plate 1. When combined, the two components are used to drive the camera device 22 to observe the object under test from multiple perspectives. A connecting base block 3 is fixedly connected to the top side of the path circular plate 1. A radial length adjustment component is provided inside the connecting base block 3. Limiting components are provided on the inner sides of both ends of the radial length adjustment component. A fixing base block 19 is fixedly connected to the other side of the connecting base block 3. A double clamping component is provided on the inner side of the fixing base block 19. A multi-directional clamping component is provided on the side of the fixing base block 19. The radial length adjustment assembly includes two first toothed block plates 13, both of which are slidably connected to the inner side of the connecting base block 3. A first drive motor 14 is fixedly connected to the inner side of the connecting base block 3. A second gear 27 is rotatably connected inside the connecting base block 3. The second gear 27 is fixedly connected to the output end of the first drive motor 14 and meshes with the sides of the two first toothed block plates 13. A first limiting slider 15 is fixedly connected to the end of each of the two first toothed block plates 13. Both first limiting sliders 15 are slidably connected to the inner side of the connecting base block 3. A first fixing block 16 is fixedly connected to the sides of each of the two first limiting sliders 15.

[0023] Specifically, the path circular plate 1 provides a mounting base for the annular path moving assembly and the lifting path assembly; the camera device 22 captures surface images of the object under test from multiple angles during the linkage scanning process; the annular path moving assembly drives the camera device 22 to perform circular motion around the object under test; the lifting path assembly drives the camera device 22 to perform vertical lifting motion; the connecting base block 3 connects the path circular plate 1 and the fixed base block 19, and provides mounting space for the radial length adjustment assembly; the radial length adjustment assembly adjusts the radial distance between the first fixed blocks 16 according to the size of the object under test; the limiting assembly limits the adjustment range of the radial length adjustment assembly; and the fixed base block 19 provides mounting space for the dual clamping assembly. The multi-directional clamping assembly provides a mounting base and fixes the object under test; the dual clamping assembly is used for main clamping and fixing of the object under test; the multi-directional clamping assembly is used for multi-directional auxiliary positioning and fixing of the object under test; the first toothed block plate 13 moves linearly under the drive of the second gear 27 to achieve radial distance adjustment; the first drive motor 14 is used to provide driving force for the radial length adjustment assembly; the second gear 27 is used to convert the rotational motion of the first drive motor 14 into the linear motion of the first toothed block plate 13; the first limiting slider 15 is used to guide the sliding of the first toothed block plate 13 and is part of the limiting assembly; the first fixing block 16 is used as the final execution component for radial length adjustment, and its position changes with adjustment.

[0024] Please see the appendix Figure 3 Appendix Figure 7 and attached Figure 8 The limiting component includes a limiting frame 28, which is slidably connected to the inner side of the first fixed block 16. Two second toothed blocks 33 are slidably connected to the inner side of the limiting frame 28. A fifth gear 47 is rotatably connected to the inner side of the first fixed block 16. The fifth gear 47 is meshed with the sides of the two second toothed blocks 33. A fourth drive motor 34 is fixedly connected to the side of the limiting frame 28. The fifth gear 47 is fixedly connected to the output end of the fourth drive motor 34. Slide plates 29 are fixedly connected to the sides of the ends of the two second toothed blocks 33. A second limiting slider 32 is slidably connected to the inner side of one end of the two slide plates 29. A slider plate 30 is slidably connected to the inner side of the other end of the two slide plates 29. The slider plate 30 is fixedly connected to the side of the second limiting slider 32. A second fixed block 31 is fixedly connected to the inner side of the two slide plates 29.

[0025] Specifically, the limiting frame 28 provides an integral mounting base and sliding track for the internal moving parts such as the second toothed block plate 33 and the slide plate 29; the fourth drive motor 34 provides a driving force source; the fifth gear 47 transmits the rotational motion output by the fourth drive motor 34 to the two second toothed blocks 33; the second toothed blocks 33 convert the rotational motion into linear motion in opposite directions or away from each other by meshing with the fifth gear 47; the slide plate 29 is fixed on the second toothed blocks 33 and moves synchronously with them, while the slide groove on its inner side provides guidance for the second limiting slider 32 and the slider plate 30; the second limiting slider 32 cooperates with the slider plate 30 and slides in the slide plate 29 to ensure the smoothness and accuracy of the movement of the second fixed block 31; the second fixed block 31, as the final execution component, realizes the limiting or clamping function of the measured object through its opposite or away movement.

[0026] Please see the appendix Figure 1 Appendix Figure 2 and attached Figure 4 The annular path moving component includes an annular toothed plate 20, which is rotatably connected to the inner side of the path circular plate 1. A first gear 21 is rotatably connected to the inner side of the path circular plate 1 and meshes with the inner side of the annular toothed plate 20. A second drive component 23 is fixedly connected to the side of the path circular plate 1, and the first gear 21 is fixedly connected to the side of the second drive component 23. A protective shell 7 is fixedly connected to the side of the path circular plate 1 and is fixedly connected to the outer side of the second drive component 23. A second base block 6 is fixedly connected to the side of the annular toothed plate 20, and a shell 5 is fixedly connected to the side of the second base block 6.

[0027] Specifically, the path circular plate 1 provides a fixed mounting base for the entire annular path moving assembly; the second drive assembly 23 provides a power source to output rotational torque; the first gear 21 transmits the rotational torque output by the second drive assembly 23 to the annular gear plate 20; the annular gear plate 20 rotates circumferentially relative to the path circular plate 1 under the drive of the first gear 21, thus serving as a motion execution platform for realizing the annular scanning path; the second base block 6 is fixed on the annular gear plate 20, providing a stable connection interface for the housing 5; the housing 5 carries the lifting path assembly and moves circumferentially together with the annular gear plate 20; the protective shell 7 shields the second drive assembly 23 to provide dust protection and safety protection.

[0028] Please see the appendix Figure 4 and attached Figure 5The lifting path assembly includes two fixed circular blocks 24, which are rotatably connected to the inner sides of both ends of the housing 5. A belt 25 is fitted on the outer side of the two fixed circular blocks 24. A camera device 22 is fixedly connected to the side of the belt 25 and slidably connected to the inner side of the housing 5. A third drive motor 26 is fixedly connected to the side of the housing 5. One of the fixed circular blocks 24 is fixedly connected to the output end of the third drive motor 26. A scanning full-field deformation analysis stiffness testing system is installed inside the camera device 22.

[0029] Specifically, the third drive motor 26 provides rotational power; the fixed block 24 supports the belt 25 and transmits the rotational power of the third drive motor 26 to the belt 25; the belt 25 carries the camera device 22 and performs cyclical motion under the drive of the fixed block 24; the housing 5 provides an installation structure for the entire lifting path assembly and provides guidance for the linear motion of the camera device 22; the camera device 22 is used to achieve lifting motion under the drive of the belt 25, thereby adjusting the shooting height to acquire surface images of different positions of the object being measured.

[0030] Please see the appendix Figure 10 - Appendix Figure 12 The dual clamping assembly includes a third gear 41 and a fourth gear 42, which are rotatably connected to the inner side of the fixed base block 19. A connecting rod 43 is fixedly connected to the inner side of the third gear 41 and the fourth gear 42. Multiple third toothed plates 44 are slidably connected to the inner side of the fixed base block 19. The third gear 41 and the fourth gear 42 are meshed with the sides of the two third toothed plates 44. Slide groove connecting blocks 46 are fixedly connected to the ends of the multiple third toothed plates 44. Third fixing blocks 45 are fixedly connected to the sides of the multiple slide groove connecting blocks 46. Multiple anti-slip protrusions 39 are fixedly connected to the sides of the third fixing blocks 45. A fifth drive assembly 40 is fixedly connected to the inner side of the fixed base block 19. The connecting rod 43 is fixedly connected to the output end of the fifth drive assembly 40.

[0031] Specifically, the fifth drive assembly 40 provides the initial driving force for the entire clamping and releasing action; the connecting rod 43 synchronously transmits the driving force output by the fifth drive assembly 40 to the third gear 41 and the fourth gear 42; the third gear 41 and the fourth gear 42 convert the received driving force into rotational motion and drive the third toothed plate 44 to perform linear motion through meshing with it; multiple third toothed plates 44 act as racks, sliding synchronously towards or away from each other under the drive of the third gear 41 and the fourth gear 42; the sliding groove connecting block 46 transmits the linear motion of the third toothed plate 44 to the third fixing block 45; the third fixing block 45 acts as a clamping claw, achieving clamping and fixing or releasing of the object under test through synchronous towards or away from each other; the anti-slip protrusion 39 increases the static friction between the contact surface of the third fixing block 45 and the object under test to ensure the stability of the clamping and prevent the object under test from slipping during subsequent loading.

[0032] Please see the appendix Figure 10 The multi-directional clamping assembly includes multiple fixing frames 12, all of which are fixedly connected to the side of the fixing base block 19. A fourth electric push rod 37 is fixedly connected to the outer side of the end of the fixing frame 12, and an arc-shaped block 38 is fixedly connected to the other end of each of the multiple fourth electric push rods 37.

[0033] Specifically, the mounting bracket 12 provides a stable mounting base for the fourth electric push rod 37; the fourth electric push rod 37 performs a telescopic action after receiving instructions from the collaborative control module c, thereby driving the arc block 38 to generate radial displacement; the arc block 38 uses its inner arc surface to abut against the outer surface of the object under test, and through the coordinated action of multiple fourth electric push rods 37, multi-point auxiliary positioning and support of the object under test are achieved to limit its unintended movement during the test.

[0034] Please see the appendix Figure 1 Appendix Figure 2 Appendix Figure 8 An axial stiffness fixture 36 is provided on the side of the fixed base block 19, and a second rotating arm node 11 is provided on the side of the axial stiffness fixture 36. A first rotating arm node 8 is provided on the top of the two first fixed blocks 16. Two third electric push rods 35 are fixedly connected to the inner side of each of the two first fixed blocks 16. The ends of the multiple third electric push rods 35 are respectively fixedly connected to the sides of the two limit frames 28. A bracket top plate 4 is fixedly connected to the side of the connecting base block 3. A first electric push rod 9 and a second electric push rod 10 are respectively fixedly connected to the side of the bracket top plate 4. An installation block 18 is fixedly connected to the end of the first electric push rod 9. A radial stiffness fixture 17 is threadedly connected inside the installation block 18. A pressure measuring block 48 is fixedly connected to the bottom of the second electric push rod 10. Multiple first base blocks 2 are fixedly connected to the bottom of the path circular plate 1.

[0035] Specifically, the fixed base 19 provides a stable mounting base for axial stiffness testing; the axial stiffness fixture 36 applies axial load to the second rotating arm node 11 mounted on the axial stiffness fixture 36; the first fixed block 16 clamps and fixes the first rotating arm node 8; the third electric push rod 35 drives the limiting frame 28 to assist in positioning and limiting the tested object; the connecting base 3 and the bracket top plate 4 together form the support structure of the radial loading device; the first electric push rod 9 drives the radial stiffness fixture 17 through the mounting block 18 to apply radial load to the first rotating arm node 8; the second electric push rod 10 drives the pressure measuring block 48 to apply preload to the tested object or to calibrate the force value; the path circular plate 1 and the first base 2 together form the base platform of the entire testing fixture, providing an installation foundation and stable support for other components.

[0036] Please see the appendix Figure 1 Appendix Figure 4 and attached Figure 5 The scanning full-field deformation analysis stiffness testing system may include the following functional components: a) loading and clamping module, b) linked scanning image acquisition module, c) collaborative control module, and d) full-field deformation analysis module.

[0037] The loading and clamping module a, in terms of physical structure, corresponds to a set of components such as a fixed base block 19, a radial length adjustment component, a double clamping component, a multi-directional clamping component, a radial stiffness fixture 17, and an axial stiffness fixture 36. Its function is to securely fix the object to be measured, such as the first rotating arm node 8 or the second rotating arm node 11, and apply a preset radial or axial load.

[0038] The linkage scanning image acquisition module b, in terms of physical structure, corresponds to a set consisting of camera device 22, a circular path moving component, and a lifting path component. Its function is to drive the lifting path component and camera device 22 to perform circular motion through the circular path moving component under the drive of the collaborative control module c, while the lifting path component adjusts the vertical position of camera device 22, thereby realizing multi-angle and multi-path scanning of the surface of the object under test and acquiring high-definition image sequences of it in different states.

[0039] The collaborative control module c is the control core of this tooling. It is electrically connected to the drive components in the loading and clamping module a, such as the first drive motor 14 and the fourth drive motor 34, as well as the drive components in the linkage scanning image acquisition module b, such as the second drive assembly 23 and the third drive motor 26. It is responsible for coordinating the timing and synchronization of a series of actions such as loading, clamping, path scanning, and image acquisition.

[0040] The full-field deformation analysis module d, typically a software system deployed in a computer or dedicated processor, receives and processes image sequences acquired by the linked scanning image acquisition module b. Based on the Digital Image Correlation (DIC) method, this module calculates the stiffness characteristics of the tested object by comparing and analyzing the changes in the three-dimensional morphology of the entire surface before and after loading.

[0041] The hardware configuration of this embodiment provides a specific structural implementation for the loading and clamping module a and the linked scanning image acquisition module b described above. The physical implementation of the linked scanning image acquisition module b mainly relies on the path circular plate 1 and the annular path moving component and the lifting path component mounted on it.

[0042] In this embodiment, the physical implementation of the loading and clamping module a mainly relies on the fixed base block 19 and the dual clamping assembly and multi-directional clamping assembly set on it. The dual clamping assembly drives the third gear 41 and the fourth gear 42 through the fifth drive assembly 40, which in turn drives multiple third toothed block plates 44 to move towards or away from each other, and finally drives the third fixed block 45 to clamp the object to be measured. The multi-directional clamping assembly includes multiple arc-shaped blocks 38 driven by the fourth electric push rod 37, which are used to assist in positioning and fixing the object to be measured.

[0043] The loading and clamping module a also includes a radial stiffness fixture 17 and an axial stiffness fixture 36 for applying loads, the application of which is performed by drive components such as the first electric push rod 9. All of the above-mentioned drive components, including the second drive assembly 23, the third drive motor 26, the fifth drive assembly 40, and various electric push rods, are electrically connected to and uniformly controlled by the collaborative control module c to ensure precise synchronization of actions such as loading, clamping, path scanning, and image acquisition.

[0044] The workflow of the scanning full-field deformation analysis stiffness test according to an embodiment of the present invention will be described in detail below. The first step of this process is test preparation and speckle preparation, which provides the necessary foundation for subsequent image acquisition and analysis.

[0045] Before conducting the stiffness test, the object to be tested, such as the first swing arm node 8 or the second swing arm node 11, is first installed into the clamping mechanism of the loading and clamping module a and then securely fixed.

[0046] To ensure the adhesion quality of the subsequent speckle pattern, the surface area of ​​the object to be analyzed needs to be cleaned to remove oil, dust, and other contaminants. This surface area to be analyzed is the main target area for scanning and imaging by the subsequent linked scanning image acquisition module b.

[0047] After cleaning, a uniform, non-reflective white primer layer is applied to the surface area to be analyzed. After the primer layer has cured, a layer of randomly distributed black spots is applied to the white primer layer by spraying or other equivalent methods, thus forming a random speckle pattern.

[0048] The random speckle pattern is isotropic and has high contrast. The size and distribution density of the speckles are adapted to the resolution and measurement field of view of the camera device 22 to ensure that the full-field deformation analysis module d can identify and track the speckles in the image. After the speckle pattern is prepared, it must be ensured that it is completely cured and remains stable, does not fall off, and does not crack during subsequent scanning and loading processes.

[0049] After completing the test preparation and speckle fabrication steps, the next step is to establish the initial three-dimensional surface digital model. This step is performed under zero load conditions where the loading and clamping module a does not apply any external load to the object under test. The purpose is to obtain the accurate three-dimensional morphology of the object under stress-free conditions, which will serve as the calculation benchmark for subsequent deformation analysis.

[0050] This step is uniformly scheduled and executed by the collaborative control module c. The collaborative control module c issues a command to start the second drive component 23 and the third drive motor 26 in the linked scanning image acquisition module b.

[0051] Specifically, the collaborative control module c controls the second drive component 23 to drive the annular path moving component, so that the circular toothed plate 20 and the entire lifting path component fixed thereon and the camera device 22 perform a circular motion around the central axis of the object being measured along a preset trajectory.

[0052] While performing circular motion, the coordination control module c controls the third drive motor 26 to drive the lifting path assembly, enabling the camera device 22 to perform a preset lifting motion in the vertical direction. The combination of the circular and lifting motions forms a spiral or segmented scanning path, ensuring that the camera device 22 can cover the prepared speckle area on the surface of the object being measured without omission from multiple different spatial perspectives.

[0053] During the entire linkage scanning process, the camera device 22 continuously captures and acquires a series of high-definition images according to a preset frequency or position point, and transmits the image sequence data to the full-field deformation analysis module d.

[0054] After receiving the complete image sequence, the full-field deformation analysis module d invokes a stereo matching and 3D reconstruction algorithm. This algorithm identifies and matches the same speckle feature point in images from different viewpoints, calculating the precise coordinates of that point in the 3D spatial coordinate system. By calculating the 3D coordinates of all identifiable speckles on the surface of the object under test, an initial 3D surface digital model of the object under test, composed of massive 3D coordinate point cloud data, is finally constructed and generated. This initial 3D surface digital model is stored and used as the zero-point reference for all subsequent deformation calculations.

[0055] After establishing the initial three-dimensional surface digital model, the next step is to load and acquire the deformed three-dimensional surface digital model. This step aims to obtain the accurate three-dimensional morphology of the object under test under a preset load, providing data for subsequent displacement field calculations.

[0056] This step is uniformly scheduled by the collaborative control module c. The collaborative control module c issues commands to the loading and clamping module a to apply a preset load to the object under test. Specifically, the collaborative control module c controls the first electric push rod 9 to drive the radial stiffness fixture 17, or controls the corresponding drive component to drive the axial stiffness fixture 36, to apply a preset, constant force F to the object under test. This force F is recorded and used for subsequent stiffness calculations.

[0057] With the load F applied and maintained in a stable state, the collaborative control module c issues another command to activate the linkage scanning image acquisition module b. The linkage scanning image acquisition module b completely replicates the scanning process described above when establishing the initial model, that is, it uses the exact same scanning path, movement speed, and image acquisition parameters to perform a second full-surface scan of the object under load.

[0058] During this process, camera device 22 acquires and generates a new high-definition image sequence, and transmits the sequence data to the full-field deformation analysis module d.

[0059] After receiving the image sequence under loading conditions, the full-field deformation analysis module d executes the same stereo matching and 3D reconstruction algorithm used when building the initial model. Through this algorithm, the system constructs and generates a deformed 3D surface digital model that reflects the true shape of the object under load F. This model is stored for comparative analysis with the aforementioned initial 3D surface digital model.

[0060] After obtaining the digital model of the deformable 3D surface, the final step is to calculate the full-field displacement and perform stiffness analysis. This step is automatically executed by the full-field deformation analysis module d, requiring no manual intervention.

[0061] The full-field deformation analysis module d first invokes the Digital Image Correlation (DIC) algorithm to register and compare the stored initial 3D surface digital model with the deformed 3D surface digital model. Specifically, this module tracks and matches the positional changes of tens of thousands of identical computational subdomains (i.e., speckle feature regions) in the two models within the 3D spatial coordinate system, calculating the 3D displacement vector of each computational subdomain, thereby generating full-field 3D displacement field data covering the entire analysis surface of the object under test. .

[0062] Full-field three-dimensional displacement field data For a composite displacement field, the relationship is shown in the following equation: ; in: To represent the total three-dimensional displacement vector field covering the surface of the object under test, calculated by comparing two three-dimensional surface digital models before and after loading; This represents the rigid body displacement vector component field generated by the three-dimensional spatial translation, tilting, or torsion of the measured object as a whole in the full-field three-dimensional displacement field data; This is to represent the pure elastic deformation displacement vector component field generated only by the elastic deformation of the measured object itself in the full-field three-dimensional displacement field data after removing the rigid body displacement component.

[0063] To obtain the displacement vector component field of pure elastic deformation The full-field deformation analysis module d further analyzes the full-field three-dimensional displacement field data vector set. Algorithm analysis is performed. Through mathematical methods such as least-squares fitting, the system can accurately solve for the rigid body motion parameters of the measured object as a whole, namely the specific values ​​of three-dimensional spatial translation, tilting, or torsion, thereby obtaining the complete rigid body displacement vector component field. Subsequently, the system uses total displacement field data... Lieutenant General rigid body displacement components By stripping, the displacement vector component field of purely elastic deformation caused by elastic deformation is obtained. .

[0064] Finally, the full-field deformation analysis module d uses the purely elastic deformation displacement vector component field calculated by the above steps. Combining the previously recorded preset load force F applied by loading and clamping module a, the stiffness characteristic value k of the measured object is finally calculated according to the following stiffness definition formula: ; in: This represents the final calculated stiffness characteristic value of the measured object; This represents the force value of the preset load applied to the object under test by the loading and clamping module a; To represent the displacement vector component field from purely elastic deformation Extracted from, under load The effective elastic deformation displacement scalar value in the direction of action (e.g., the modulus of the elastic displacement component at the loading point).

[0065] Calculated stiffness characteristic values This is the final result of this test, and it will be output and recorded by the system.

[0066] The core measurement principle of this invention is based on the 3D digital image correlation (3D-DIC) method. Its foundation lies in the simultaneous capture of a pre-prepared random speckle pattern on the surface of the object being measured using a binocular stereo vision system (camera device 22). The images acquired by the left and right cameras are then stereo matched using the full-field deformation analysis module d to reconstruct the 3D coordinate point cloud of the object's surface. By comparing the 3D coordinate point clouds before and after loading, the surface displacement field can be calculated.

[0067] In traditional fixed 3D-DIC applications, the camera device 22 remains in a fixed position and can only acquire local surface 3D information within its field of view. The shape and deformation of the back, sides, or occluded areas of the object under test cannot be measured. This incomplete surface data limits the analysis of complex spatial motions of the object under test, especially when accurately separating rigid body displacement from elastic deformation, as insufficient data can introduce calculation errors.

[0068] The technical solution of this embodiment provides a solution to this problem by configuring the linked scanning image acquisition module b. The collaborative control module c drives the circular path moving component and the lifting path component, causing the camera device 22 to perform a composite movement around the object under test along a preset path. This process enables the camera device 22 to acquire image sequences of the object under test from multiple different spatial perspectives.

[0069] The full-field deformation analysis module d receives and processes image sequences from all different viewpoints. Using a 3D reconstruction algorithm, it registers and fuses multiple 3D point cloud data acquired from various local viewpoints into a unified global coordinate system, ultimately generating a panoramic 3D surface digital model covering the entire analysis surface of the object under test. This process is executed under both zero-load and loaded conditions, thus obtaining two complete panoramic 3D surface digital models: the initial model and the deformed model.

[0070] Obtaining a complete panoramic 3D surface digital model is essential for accurately separating rigid body displacement components. The technical prerequisite is that the motion of a rigid body in three-dimensional space has six degrees of freedom—three translational components and three rotational components. Accurately solving for these six parameters depends on a global observation of the displacement distribution across the entire surface of the object. Displacement field data covering the entire surface provides sufficient data redundancy and geometric constraints for algorithms such as least-squares fitting, enabling them to robustly and accurately calculate the overall rigid body displacement without bias or error in the solution due to the partiality of local data.

[0071] Therefore, this solution acquires panoramic data through linked scanning, elevating the measurement from a local surface to the entire surface, thus paving the way for subsequent acquisition of full-field three-dimensional displacement field data. Accurate separation of rigid body displacement components It provides complete and necessary data input, which is essential for ultimately obtaining the displacement vector component field of purely elastic deformation. And calculate the true stiffness characteristic value. The fundamental technological guarantee.

[0072] The algorithm principle for separating rigid body displacements in this embodiment of the invention will be explained below. This algorithm is executed by the full-field deformation analysis module d, and its purpose is to separate the calculated full-field three-dimensional displacement field data... In this process, the rigid body displacement components are accurately solved and extracted. .

[0073] The algorithm is based on the following mathematical model: the motion of any rigid body in three-dimensional space can be decomposed into a combination of rotational and translational motions. Therefore, for any point on the surface of the object being measured, its spatial position after undergoing pure rigid body motion can be accurately described by a rotation matrix and a translation vector.

[0074] Specifically, let the first part of the initial three-dimensional surface digital model participating in the calculation be... The coordinate vectors of the feature points are Its corresponding point coordinate vector in the deformable three-dimensional surface digital model is The goal of the full-field deformation analysis module d is to find an optimal rotation matrix. Translation vector This allows the initial point cloud after the rotation and translation transformation to achieve the best fit with the deformed point cloud.

[0075] To achieve this goal, the full-field deformation analysis module d constructs and solves a least-squares problem. Specifically, it seeks the optimal rotation matrix. Translation vector To minimize the sum of squared residuals between all corresponding points : ; in: Let this represent the objective function to be minimized, namely the sum of squared residuals; The point index on the 3D model of the surface of the object being measured, from 1 to... ; This represents the total number of points on the surface model involved in the calculation. Let i be the coordinate vector of the i-th feature point in the deformed 3D surface digital model after loading. Let be the coordinate vector of the i-th feature point in the initial three-dimensional surface digital model before loading; It is a 3x3 rotation matrix that describes the rotational motion of the rigid body; It is a 3x1 translation vector that describes the translational motion of the rigid body; Let be the square of the Euclidean norm of the vector.

[0076] By solving the aforementioned least-squares problem using a numerical optimization algorithm, the full-field deformation analysis module d can obtain a uniquely determined optimal rotation matrix. Translation vector These two parameters fully describe the overall rigid body motion of the object under test during the test.

[0077] In obtaining and Then, for any point on the surface Its rigid body displacement vector components It can be calculated precisely: ; Finally, the full-field deformation analysis module d obtains the total displacement vector at that point. Subtract its rigid body displacement vector components This allows us to obtain the displacement vector components at that point that are purely caused by elastic deformation. This achieves precise separation of displacements. Performing this operation on all points yields the complete vector component field of the purely elastic deformation displacement. .

[0078] Working Principle: First, the radial length adjustment component, dual clamping component, and multi-directional clamping component precisely adapt and securely fix the rotating arm node to be tested. Then, under zero load, the camera device 22 is driven to scan the entire surface of the object under test through the coordinated linkage of the annular path moving component and the lifting path component, acquiring images and establishing an initial three-dimensional surface digital model. Next, a preset load is applied through the first electric push rod 9 or the axial stiffness fixture 36, and while the load is maintained, the camera device 22 is driven again to perform a second full-surface scan along the exact same path, establishing a deformed three-dimensional surface digital model. Finally, the scanning full-field deformation analysis stiffness testing system compares and analyzes the two three-dimensional models before and after loading, calculates the full-field displacement, accurately separates the purely elastic deformation, and calculates the stiffness of the object under test based on the load value.

[0079] During test preparation, the radial length adjustment assembly is first activated, and the first drive motor 14 starts, with its output driving the second gear 27 to rotate. Since the second gear 27 meshes with both first toothed plates 13 simultaneously, its rotation will drive the two first toothed plates 13 and the first fixed blocks 16 fixed on them to move synchronously towards or away from each other, thereby adjusting the radial distance between the two first fixed blocks 16 to accommodate test objects of different sizes.

[0080] After dimensional adaptation, the object to be measured is placed in the fixture, and the dual-clamping assembly is activated. The fifth drive assembly 40 is activated, synchronously driving the third gear 41 and the fourth gear 42 to rotate via the connecting rod 43. Since the gears mesh with the third toothed plate 44, the rotation of the gears will drive multiple third toothed plates 44 to slide towards each other, thereby causing the third fixing block 45 to clamp the object to be measured. Multiple anti-slip protrusions 39 on the surface of the third fixing block 45 increase the friction and ensure the stability of the clamping. At the same time, the multi-directional clamping assembly can be activated, and multiple fourth electric push rods 37 extend, driving the arc-shaped block 38 to abut against the object to be measured from multiple directions, providing auxiliary positioning and support.

[0081] After the object under test is fixed, the initial 3D model is established under zero load. The collaborative control module c activates the circular path movement component and the lifting path component. First, the second drive component 23 is activated, driving the first gear 21 to rotate. The first gear 21 meshes with the inner side of the circular gear plate 20, thereby driving the circular gear plate 20 and the outer shell 5 fixed on it to perform a circular motion. At the same time, the third drive motor 26 is activated, driving one of the fixed circular blocks 24 to rotate, and driving the camera device 22 fixed on it to perform a lifting motion inside the outer shell 5 through the belt 25. The combination of the above circular motion and lifting motion enables the camera device 22 to perform a full surface scan of the object under test and acquire images along a preset trajectory.

[0082] When applying load, if a radial stiffness test is to be performed, the first electric actuator 9 is activated, which drives the radial stiffness fixture 17 via the mounting block 18 to apply a constant radial force to the first swing arm node 8. If an axial stiffness test is to be performed, the axial stiffness fixture 36 is activated to apply an axial force to the second swing arm node 11. Throughout the loading process, the load values ​​are accurately recorded.

[0083] Under a stable load, the scanning process described above is repeated. That is, the annular path moving component and the lifting path component are restarted, driving the camera device 22 to perform a second full-surface scan with identical path parameters, acquiring image sequences of the object under deformation. The two sets of image sequences are used to reconstruct two complete three-dimensional surface digital models before and after loading, providing a data basis for subsequent stiffness calculations.

Claims

1. A fixture for testing the stiffness of a swing arm node, characterized in that, It includes a path circular plate (1) and a camera device (22). The path circular plate (1) is provided with a ring path moving component inside. The path circular plate (1) is slidably connected to a lifting path component on its inner side. When combined, the components are used to drive the camera device (22) to observe the object under test from multiple angles. The path circular plate (1) is fixedly connected to a connecting base block (3) on its top side. A radial length adjustment component is provided inside the connecting base block (3). Limiting components are provided on the inner sides of both ends of the radial length adjustment component. A fixing base block (19) is fixedly connected to the other side of the connecting base block (3). A double clamping component is provided on the inner side of the fixing base block (19). A multi-directional clamping component is provided on the side of the fixing base block (19). The radial length adjustment assembly includes two first toothed blocks (13), both of which are slidably connected to the inner side of the connecting base block (3). A first drive motor (14) is fixedly connected to the inner side of the connecting base block (3). A second gear (27) is rotatably connected inside the connecting base block (3). The second gear (27) is fixedly connected to the output end of the first drive motor (14). The second gear (27) is meshed with the sides of the two first toothed blocks (13). A first limiting slider (15) is fixedly connected to the ends of the two first toothed blocks (13). Both first limiting sliders (15) are slidably connected to the inner side of the connecting base block (3). A first fixing block (16) is fixedly connected to the sides of the two first limiting sliders (15).

2. The swing arm node stiffness testing fixture according to claim 1, characterized in that, The limiting component includes a limiting frame (28), which is slidably connected to the inner side of the first fixing block (16). Two second toothed blocks (33) are slidably connected to the inner side of the limiting frame (28). A fifth gear (47) is rotatably connected to the inner side of the first fixing block (16). The fifth gear (47) is meshed with the sides of the two second toothed blocks (33). A fourth drive motor (34) is fixedly connected to the side of the limiting frame (28). The fifth gear (47) is fixedly connected to the output end of the fourth drive motor (34). Slide plates (29) are fixedly connected to the sides of the ends of the two second toothed blocks (33). A second limiting slider (32) is slidably connected to the inner side of one end of the two slide plates (29). A slider plate (30) is slidably connected to the inner side of the other end of the two slide plates (29). The slider plate (30) is fixedly connected to the side of the second limiting slider (32). A second fixing block (31) is fixedly connected to the inner side of the two slide plates (29).

3. The swing arm node stiffness testing fixture according to claim 1, characterized in that, The annular path moving assembly includes an annular toothed plate (20), which is rotatably connected to the inner side of the path circular plate (1). A first gear (21) is rotatably connected to the inner side of the path circular plate (1), and the first gear (21) is meshed with the inner side of the annular toothed plate (20). A second driving assembly (23) is fixedly connected to the side of the path circular plate (1), and the first gear (21) is fixedly connected to the side of the second driving assembly (23). A protective shell (7) is fixedly connected to the side of the path circular plate (1), and the protective shell (7) is fixedly connected to the outer side of the second driving assembly (23). A second base block (6) is fixedly connected to the side of the annular toothed plate (20), and a shell (5) is fixedly connected to the side of the second base block (6).

4. The swing arm node stiffness testing fixture according to claim 3, characterized in that, The lifting path assembly includes two fixed circular blocks (24), which are rotatably connected to the inner sides of both ends of the outer shell (5). A belt (25) is fitted on the outer side of the two fixed circular blocks (24). The camera device (22) is fixedly connected to the side of the belt (25) and slidably connected to the inner side of the outer shell (5). A third drive motor (26) is fixedly connected to the side of the outer shell (5). One of the fixed circular blocks (24) is fixedly connected to the output end of the third drive motor (26). The camera device (22) is equipped with a scanning full-field deformation analysis stiffness test system.

5. The swing arm node stiffness testing fixture according to claim 1, characterized in that, The dual clamping assembly includes a third gear (41) and a fourth gear (42). The third gear (41) and the fourth gear (42) are respectively rotatably connected to the inner side of the fixed base block (19). A connecting rod (43) is fixedly connected to the inner side of the third gear (41) and the fourth gear (42). Multiple third toothed plates (44) are slidably connected to the inner side of the fixed base block (19). The third gear (41) and the fourth gear (42) are meshed and connected to the sides of the two third toothed plates (44). A sliding groove connecting block (46) is fixedly connected to the end of the multiple third toothed plates (44). A third fixing block (45) is fixedly connected to the side of the multiple sliding groove connecting blocks (46). Multiple anti-slip protrusions (39) are fixedly connected to the side of the third fixing block (45). A fifth drive assembly (40) is fixedly connected to the inner side of the fixed base block (19). The connecting rod (43) is fixedly connected to the output end of the fifth drive assembly (40).

6. The swing arm node stiffness testing fixture according to claim 1, characterized in that, The multi-directional clamping assembly includes multiple fixing frames (12), each of which is fixedly connected to the side of the fixing base block (19). A fourth electric push rod (37) is fixedly connected to the outer side of the end of each fixing frame (12), and an arc-shaped block (38) is fixedly connected to the other end of each of the multiple fourth electric push rods (37).

7. The swing arm node stiffness testing fixture according to claim 2, characterized in that, The fixed base block (19) is provided with an axial stiffness fixture (36) on its side, and a second rotating arm node (11) is provided on the side of the axial stiffness fixture (36). The top of the two first fixed blocks (16) is provided with a first rotating arm node (8). The inner sides of the two first fixed blocks (16) are fixedly connected to two third electric push rods (35). The ends of the multiple third electric push rods (35) are respectively fixedly connected to the sides of the two limit frames (28). The side of the connecting base block (3) is fixedly connected to a bracket top plate (4). The side of the bracket top plate (4) is fixedly connected to a first electric push rod (9) and a second electric push rod (10). The end of the first electric push rod (9) is fixedly connected to an installation block (18). The installation block (18) is internally threaded with a radial stiffness fixture (17). The bottom of the second electric push rod (10) is fixedly connected to a pressure measuring block (48). The bottom of the path circular plate (1) is fixedly connected to multiple first base blocks (2).

8. The swing arm node stiffness testing fixture according to claim 4, characterized in that, The overall working method of the rotating arm node stiffness testing fixture includes the following steps: Before applying a load to the object under test, the ring path moving component and the lifting path component are linked to drive the camera device (22) to scan the object under test in order to capture and establish an initial three-dimensional surface digital model of the object under test. A preset radial or axial load is applied to the object under test using the radial stiffness fixture (17) or the axial stiffness fixture (36). Under load holding conditions, the ring path moving component and the lifting path component are controlled to work together again to drive the camera device (22) to scan the deformed test object in order to capture and establish a digital model of the deformed three-dimensional surface of the test object after loading. The swing arm node stiffness testing fixture calculates the full-field three-dimensional displacement field data of the tested object by comparing and analyzing the initial three-dimensional surface digital model and the deformed three-dimensional surface digital model.

9. The swing arm node stiffness testing fixture according to claim 8, characterized in that, The step of calculating the full-field three-dimensional displacement field data of the measured object further includes: Algorithm analysis is performed on the full-field three-dimensional displacement field data to identify and separate the rigid body displacement components caused by the overall translation, tilting or torsion of the measured object, and the purely elastic deformation displacement components caused only by the deformation of the measured object itself.

10. The swing arm node stiffness testing fixture according to claim 9, characterized in that, The swing arm node stiffness testing fixture uses the purely elastic deformation displacement component obtained by separating the rigid body displacement component from the full-field three-dimensional displacement field data, combined with the preset loading force value, to calculate the most realistic stiffness characteristic value of the tested object.

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