Non-contact extensometer calibration device

Abstract

This invention discloses a non-contact extensometer calibration device, specifically relating to the field of non-contact extensometer technology. It includes an extensometer body with a camera, a fixing fixture, a posture correction unit, and a calibration target plate. The device uses the fixing fixture to quickly and securely assemble the calibration target plate onto the test sample side. By setting the posture correction unit between the fixing fixture and the calibration target plate, the device can control the calibration target plate to complete a full loop motion according to trajectories a, b, c, and d. During calibration, calibration points with different object distances can be acquired at the same gauge length height, and calibration points with different gauge length heights can be acquired at the same object distance. Furthermore, calibration points can be started and stopped at any position on the loop trajectory according to calibration requirements. Through the acquisition of calibration data from multiple sets of different working conditions, a calibration parameter system covering multiple object distances and gauge lengths is constructed. This device has high integration and can automatically and continuously complete multi-working-condition calibration processes.

Description

Technical Field

[0001] This invention relates to the field of non-contact extensometer technology, and more particularly to a non-contact extensometer calibration device. Background Technology

[0002] Extensometers are core devices used in material mechanical property testing to detect the deformation and strain of specimens. They are widely used in various mechanical testing scenarios such as tension, compression, and three-point bending. Among them, non-contact video extensometers are compatible with various electronic universal testing machines and other mechanical testing equipment. Based on the principles of optical imaging and sub-pixel analysis, they use an industrial camera to acquire complete images of the specimen during the stress process in real time. They optically track the marked points, lines, or inherent texture features on the specimen surface. After image comparison analysis and analog-to-digital conversion, they simultaneously acquire the longitudinal and transverse deformation of the specimen in a non-contact manner. The measurement range is determined by the lens focal length. By configuring lenses with different focal lengths, different measurement ranges can be achieved. Compared with traditional contact extensometers, non-contact extensometers, as the core means of strain acquisition under static load on materials, have advantages such as a large dynamic stroke range, flexible gauge length setting, no knife-edge scratches or slippage problems, and adaptability to ultra-high temperature environment testing. They are applicable to the mechanical testing of almost all materials and have been widely used in recent years for the determination of mechanical property indicators in uniaxial tensile tests.

[0003] Based on the working principle of the non-contact video extensometer, its measurement accuracy is highly dependent on the pre-calibration process. It is necessary to establish the mapping relationship between image pixels and actual physical dimensions (pixel equivalent) through the calibration target plate, and at the same time ensure that the calibration reference axis coincides with the force axis of the sample and the calibration target surface is parallel to the camera imaging plane. Otherwise, systematic measurement errors will be introduced. Currently, most calibration operations in the industry involve manual alignment of the calibration target plate by hand. Operators manually align the calibration target plate with the sample axis and adjust the target surface posture to complete the calibration. This method suffers from low alignment accuracy, poor repeatability, and large subjective human errors, directly affecting the accuracy of the calibration results. To address the errors caused by manual placement, existing technologies often use connecting components to fix the calibration target plate to the sample or testing machine chuck, such as clamping it to the sample surface, magnetically attaching it, or attaching it to the testing machine chuck. However, among these methods, clamping can easily cause indentation damage to the sample surface and has insufficient reference stability. Attaching it to the chuck introduces a fixed system error where the calibration reference does not coincide with the force axis of the sample. Magnetic attachment has poor positioning accuracy and vibration resistance, resulting in unsatisfactory performance. Furthermore, traditional calibration is often a single fixed-position calibration or a decentralized calibration operation that requires separate adjustments to height and object distance. This results in large equipment footprint, low integration, cumbersome multi-condition calibration processes, low calibration efficiency, and an inability to cover the full-condition calibration needs with multiple object distances and gauge lengths.

[0004] Therefore, this application proposes a non-contact extensometer calibration device. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a non-contact extensometer calibration device.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A non-contact extensometer calibration device includes an extensometer body with a camera, a fixing fixture, a posture correction unit, and a calibration target plate. The posture correction unit is connected between the fixing fixture and the calibration target plate. The calibration target plate has calibration dots arranged in an array on its surface facing the camera. The calibration target plate and the posture correction unit are mounted on the sample testing side of the extensometer body through the fixing fixture. The posture correction unit includes a support base, a movable frame, a movable seat, a deflection adjustment mechanism, and a drive mechanism; The movable seat is fixed on the fixed fixture and has a U-shaped guide groove. The movable frame slides laterally on the support seat and the movable seat slides longitudinally inside the movable frame. The deflection adjustment mechanism is set between the movable seat and the calibration target plate to adjust the target surface attitude of the calibration target plate. The driving mechanism is disposed between the movable seat and the support seat, and is configured to drive the movable frame to reciprocate along the horizontal direction of the sample, and to drive the movable seat to reciprocate along the axial direction of the sample, so as to drive the calibration target plate to move along a loop trajectory.

[0007] As a further embodiment of the present invention, one end of the movable frame is slidably sleeved on the support base, and a sliding component is provided between the movable base and the movable frame. The sliding component includes a T-shaped groove and a T-shaped slider. The T-shaped slider is fixedly connected to the end of the movable base, and the T-shaped groove is opened on the inner side of the movable frame, and the T-shaped slider and the T-shaped groove slide in cooperation.

[0008] As a further embodiment of the present invention, the driving mechanism includes a plurality of stop posts, a drive motor, drive teeth and guide posts; The drive motor is installed inside the movable seat, and its output end is connected to the drive teeth. The drive teeth are located on one side of the loop guide groove. Several of the stop pins are arranged at intervals along the extension direction of the loop guide groove on the side wall of the support seat, and the drive teeth mesh with each stop pin in sequence. The guide post is coaxially disposed at the shaft end of the drive tooth, and the guide post is slidably embedded in the spiral guide groove.

[0009] As a further embodiment of the present invention, the deflection adjustment mechanism includes a positioning seat, a rotating frame, a transmission component, an anti-detachment component, and a linkage mechanism; The positioning seat is fixedly connected to the movable seat, and its end is provided with an arc-shaped groove. The rotating frame is rotatably connected to the arc-shaped groove through an anti-detachment component, and it is fixedly connected to the calibration target plate. The transmission component includes a worm, a worm wheel, and a transmission rod. The worm is rotatably connected to the inner cavity of the positioning seat, the transmission rod is disposed in the inner cavity of the rotating frame, and the worm wheel is disposed on the transmission rod and meshes with the worm. The linkage mechanism includes a linkage component and a displacement component. The displacement component is configured to drive the drive motor and drive teeth to move, so as to switch the meshing state of the drive teeth and the stop column. When the drive tooth disengages from the stop post, the linkage engages, and the drive motor drives the worm gear to rotate via the linkage. When the drive tooth meshes with the stop post, the linkage disengages, and the drive motor drives the calibration target plate to move along a loop trajectory via the engagement of the drive tooth and the stop post.

[0010] As a further embodiment of the present invention, the anti-detachment component includes arc-shaped limiting grooves symmetrically opened at both ends of the inner side of the arc-shaped groove and two arc-shaped limiting blocks symmetrically arranged at the rotating end of the rotating frame, wherein the arc-shaped limiting blocks are slidably fitted in the arc-shaped limiting grooves.

[0011] As a further embodiment of the present invention, the linkage includes a first gear and a second gear, the first gear being disposed between the drive gear shaft end and the drive motor, the second gear being disposed at the end of the worm gear, and the first gear and the second gear meshing together. The displacement component includes an electric push rod, which is fixedly connected to one end of the interior of the movable base, and its output end is connected to a drive motor, which is slidably mounted on the inside of the movable base.

[0012] As a further embodiment of the present invention, a limiting component is also included. The limiting component includes a pressure block and a second spiral guide groove. The second spiral guide groove is opened in the support base and located outside the first spiral guide groove. The pressure block is slidably assembled in the second spiral guide groove. The end of the guide post extends into the second spiral guide groove and is connected to the pressure block. When the drive tooth moves away from the stop post and the linkage engages, the pressure block moves synchronously with the guide post and presses against the grooves of the second and first guide grooves.

[0013] As a further embodiment of the present invention, the fixing fixture includes a fixed base, two sets of L-shaped clamps and two sets of hydraulic rods. The two sets of hydraulic rods are symmetrically arranged at both ends of the fixed base, and the output ends of the two sets of hydraulic rods are symmetrically provided with connecting seats. The two connecting seats are respectively fixedly connected to the two sets of L-shaped clamps, and at least one set of telescopic rods is provided between the connecting seats and the fixed base. Rubber anti-slip pads are provided on the inner side of both sets of L-shaped clamps.

[0014] The technical effects and advantages provided by the present invention in the above technical solution are as follows: This invention allows for the rapid and convenient installation of a calibration target plate onto the test sample side using a fixed fixture. The installation position is flexible and adjustable, and disassembly and assembly are easy, without occupying sample clamping space. A posture correction unit is installed between the fixed fixture and the calibration target plate. Its upper displacement component controls the drive gear to mesh with the stop post, while the linkage component disengages. At this point, the calibration target plate can be controlled to complete a full loop motion according to trajectories a, b, c, and d. During calibration, calibration points with different object distances can be obtained at the same gauge length height, and calibration points with different gauge length heights can be obtained at the same object distance. Furthermore, calibration points can be started and stopped at any position on the loop trajectory according to calibration requirements. Through the acquisition of calibration data from multiple sets of different working conditions, a calibration parameter system covering multiple object distances and gauge lengths is constructed. This system has high integration and can automatically and continuously complete multi-working-condition calibration processes, greatly improving calibration efficiency and the comprehensiveness and accuracy of calibration results. The displacement component controls the movement of the drive gear and disengages from the stop column, while the linkage component synchronously completes the engagement transmission. This allows the rotating frame to deflect along the axis of the arc groove, adjust the tilt angle of the calibration target plate, keep the target surface parallel to the imaging plane of the camera, and perform real-time correction of the target surface attitude. This enables multi-position and multi-attitude full-condition calibration, greatly improving calibration accuracy and the coverage of calibration conditions. By setting a limit component, when switching working modes, when the drive tooth moves away from the stop column and the linkage engages, the pressure block moves axially synchronously with the guide column and presses against the adjacent groove walls of the second and first guide grooves. By increasing the static friction between the contact surfaces, the moving frame is restricted from sliding laterally along the support base, thereby preventing the calibration target plate from shifting horizontally and ensuring the positional stability of the calibration reference during the target attitude adjustment stage. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is one of the overall structural schematic diagrams of the present invention; Figure 2 This is the second schematic diagram of the overall structure of the present invention; Figure 3 This is a schematic diagram of the structure of the calibration target plate of the present invention being fixedly installed on the extensometer body; Figure 4 This is a schematic diagram of the connection between the fixing fixture and the calibration target plate of the present invention; Figure 5 This is one of the schematic diagrams showing the connection structure between the support base and the calibration target plate of the present invention; Figure 6 This is the second schematic diagram of the connection structure between the support base and the calibration target plate of the present invention; Figure 7 This is a longitudinal sectional view of the movable frame and movable base of the present invention; Figure 8 This is a schematic diagram of the structure of the support base of the present invention; Figure 9 This is a schematic diagram of the changing structure of the pressure block of the present invention moving within the second spiral guide groove; Figure 10 This is a schematic diagram of the structure when the first gear and the second gear of the present invention are engaged; Figure 11 This is a schematic diagram of the connection structure between the positioning seat and the rotating frame of the present invention; Figure 12 This is a schematic diagram of the positioning base of the present invention.

[0016] In the picture: 100. Extensometer body; 200. Fixed base; 201. L-shaped clamp; 202. Hydraulic rod; 203. Connecting seat; 300. Calibrate the target plate; 301. Calibrate the dot; 400. Support base; 401. U-shaped guide groove one; 402. Stop post; 500. Moving frame; 501. Moving base; 502. Drive motor; 503. Drive gear; 504. Guide post; 5011. T-shaped slide rail; 5012. T-shaped slider; 600. Positioning seat; 601. Rotary frame; 602. Worm gear; 603. Worm wheel; 700. Electric actuator; 701. First gear; 702. Second gear; 800. Pressing block; 801. Recurved guide groove II; 900, Arc-shaped limiting block; 901, Arc-shaped limiting groove. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of 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.

[0018] like Figures 1-4As shown, the present invention provides a non-contact extensometer calibration device, including an extensometer body 100 with a camera, a fixing fixture, a posture correction unit, and a calibration target plate 300. The posture correction unit is connected between the fixing fixture and the calibration target plate 300. The calibration target plate 300 has calibration dots 301 arranged in an array on the surface facing the camera. The calibration target plate 300 and the posture correction unit are mounted on the sample testing side of the extensometer body 100 through the fixing fixture. In this embodiment, as a preferred implementation, the fixing fixture includes a fixing base 200, two sets of L-shaped clamping plates 201, and two sets of hydraulic rods 202. The two sets of hydraulic rods 202 are symmetrically arranged at both ends of the fixing base 200, and the output ends of the two sets of hydraulic rods 202 are symmetrically provided with connecting seats 203. The two connecting seats 203 are respectively fixedly connected to the two sets of L-shaped clamping plates 201, and at least one set of telescopic rods is provided between the connecting seats 203 and the fixing base 200. Rubber anti-slip pads are provided on the inner side of the two sets of L-shaped clamping plates 201. The rubber anti-slip pads are mainly used to increase the clamping friction and protect the surface of the gantry frame.

[0019] During assembly, the initial installation height of the device is selected according to the sample length, so that the calibration target plate 300 is located on the test side of the sample and initially aligned with it. Then, the distance between the two sets of L-shaped clamping plates 201 is adjusted by the hydraulic rod 202, so that one side plate of the two sets of L-shaped clamping plates 201 can be attached to the outer wall of the gantry of the extensometer body 100. After the position is aligned, the two sets of L-shaped clamping plates 201 are continued to be driven to feed, so that the inner right-angled surface of the L-shaped clamping plate 201 is pressed against the inner wall of the gantry. Even if the L-shaped clamping plate 201 is fully attached to the right-angled edge of the gantry, the rigid fixation of the fixed base 200 is achieved by double-sided circumferential clamping. This allows for the positioning and installation of the calibration target plate 300 on the test side of the sample. Compared to traditional methods such as manual support, installation attached to the extensometer body 100 clamp, or magnetic installation on the clamp, this fixing fixture allows for flexible adjustment of the installation position along the vertical of the gantry according to the sample length, adapting to different testing needs. It is easy to assemble and disassemble, and adopts a double-sided clamping structure with right-angle surface adaptation, resulting in high positioning and centering accuracy, strong clamping anti-shake capability, and good reference stability during calibration. At the same time, it does not require modification of the original clamp of the extensometer body 100, does not occupy the sample clamping space, and will not interfere with the subsequent tensile test process.

[0020] like Figures 3-11 As shown, the posture correction unit includes a support base 400, a movable frame 500, a movable seat 501, a deflection adjustment mechanism, and a drive mechanism. The movable seat 501 is fixed on the fixed fixture and has a U-shaped guide groove 401. The movable frame 500 slides laterally on the support seat 400 and slides longitudinally inside the movable frame 500. Furthermore, one end of the movable frame 500 is slidably sleeved on the support seat 400. A sliding assembly is provided between the movable seat 501 and the movable frame 500. The sliding assembly includes a T-shaped groove 5011 and a T-shaped slider 5012. The T-shaped slider 5012 is fixedly connected to the end of the movable seat 501. The T-shaped groove 5011 is opened on the inner side of the movable frame 500, and the T-shaped slider 5012 slides in cooperation with the T-shaped groove 5011. The driving mechanism is located between the movable seat 501 and the support seat 400, and is configured to drive the movable frame 500 to reciprocate along the horizontal direction of the sample, and to drive the movable seat 501 to reciprocate along the axis of the sample, so as to drive the calibration target plate 300 to move along the loop trajectory.

[0021] In one specific embodiment of the present invention, reference is made to... Figure 6 , Figure 7 and Figure 8 It can be seen that the drive mechanism includes several stop posts 402, drive motor 502, drive gear 503 and guide post 504; The drive motor 502 is installed inside the movable seat 501. Its output end is connected to the drive tooth 503. The drive tooth 503 is located on one side of the loop guide groove 401. Several stop posts 402 are arranged at intervals along the extension direction of the loop guide groove 401 on the side wall of the support seat 400. The drive tooth 503 and each stop post 402 mesh with each other in sequence. The guide post 504 is coaxially disposed on the shaft end of the drive gear 503, and the guide post 504 is slidably embedded in the spiral guide groove 401.

[0022] By activating the drive motor 502, the drive motor 502 drives the drive gear 503 to rotate. The tooth grooves of the drive gear 503 mesh with the sequentially arranged stop posts 402, converting the rotational motion into a traveling motion along the direction of the loop-shaped guide groove 401. At the same time, the guide posts 504 are slidably embedded in the loop-shaped guide groove 401 to form a trajectory constraint. Then, through the moving seat 501 and the moving frame 500, the calibration target plate 300 is driven to perform a composite motion along the contour of the loop-shaped guide groove 401. The specific motion trajectory is executed sequentially in the following four segments: by Figure 8When the drive tooth 503 is in its initial position and moves counterclockwise, the drive tooth 503 drives the guide post 504 to move along the upper horizontal path of the loop guide groove 401 (hereinafter referred to as trajectory a). The drive tooth 503 drives the moving seat 501 and the moving frame 500 to slide horizontally away from the sample along the support seat 400. The calibration target plate 300 slides accordingly, the object distance gradually increases, and the vertical gauge height remains constant. When moving along the left arc transition path of the loop guide groove 401 (trajectory b), the guide post 504 is laterally constrained by the arc groove wall, which drives the moving seat 501 to slide vertically downward in the moving frame 500. The calibration target plate 300 descends along the sample axis, the object distance remains unchanged, and the vertical gauge height changes. When traveling along the horizontal path (hereinafter referred to as trajectory c) of the guide groove 401, the calibration target plate 300 moves synchronously with the moving seat 501, the object distance gradually decreases, and the vertical gauge height remains constant. When traveling along the right arc transition path (trajectory d), the guide post 504 is laterally constrained by the arc-shaped groove wall, which drives the moving seat 501 to slide vertically upward within the moving frame 500. The calibration target plate 300 rises along the sample axis, the object distance remains unchanged, the vertical gauge height changes, and finally returns to the initial position, completing a complete loop motion cycle. Through the aforementioned loop-shaped trajectory movement, calibration points with different object distances can be obtained at the same gauge length height during the calibration process, and calibration points with different gauge length heights can be obtained at the same object distance. Furthermore, calibration points can be started and stopped at any position on the loop-shaped trajectory according to calibration requirements. By collecting calibration data from multiple sets of different working conditions, a calibration parameter system covering multiple object distances and multiple gauge lengths can be constructed. Compared with traditional single fixed calibration methods or decentralized calibration operations, this solution has a high degree of integration and can automatically and continuously complete the multi-working-condition calibration process, greatly improving calibration efficiency and the comprehensiveness and accuracy of calibration results.

[0023] like Figures 5-6 and Figures 10-12 As shown, the deflection adjustment mechanism is located between the movable seat 501 and the calibration target plate 300, and is used to adjust the target surface attitude of the calibration target plate 300. Specifically: The deflection adjustment mechanism includes a positioning seat 600, a rotating frame 601, transmission components, anti-detachment components, and a linkage mechanism; The positioning seat 600 is fixedly connected to the movable seat 501, and its end is provided with an arc-shaped groove. The rotating frame 601 is rotatably connected to the arc-shaped groove through an anti-detachment component, and it is fixedly connected to the calibration target plate 300. The transmission components include a worm 602, a worm wheel 603, and a transmission rod. The worm 602 is rotatably connected to the inner cavity of the positioning seat 600, the transmission rod is disposed in the inner cavity of the rotating frame 601, and the worm wheel 603 is disposed on the transmission rod and meshes with the worm 602.

[0024] The linkage mechanism includes a linkage component and a displacement component. The displacement component is configured to drive the drive motor 502 and the drive gear 503 to move, so as to switch the meshing state of the drive gear 503 and the stop post 402. The electric push rod 700 acts as a displacement component, driving the drive motor 502 to move axially, causing the drive gear 503 to move and disengage from the stop post 402. At the same time, the first gear 701 located on the side of the drive gear 503 moves synchronously with the shaft and meshes with the second gear 702 on the side of the positioning seat 600, completing the engagement transmission of the linkage. At this time, the drive motor 502 drives the worm gear 602 to rotate through the engaged linkage, causing the worm gear 602 to drive the worm wheel 603 to rotate. The worm wheel 603 drives the rotating frame 601 fixed to its end to deflect along the axis of the arc groove through the transmission rod, thereby driving the calibration target plate 300 to deflect synchronously, so as to adjust the target surface tilt angle of the calibration target plate 300, so that the target surface is parallel to the imaging plane of the camera, eliminating perspective projection distortion. Conversely, when the displacement component re-controls the drive gear 503 to mesh with the stop post 402, the linkage component is disconnected, and the drive motor 502 drives the calibration target plate 300 to move along the loop trajectory through the cooperation of the drive gear 503 and the stop post 402. At this time, the transmission component self-locks to keep the target surface of the calibration target plate 300 fixed. Through the coordinated operation of the above structures, a single drive motor 502 can be used to achieve two functions: the loop trajectory movement of the calibration target plate 300 and the target surface attitude adjustment. It can also switch to attitude adjustment mode during the calibration of the calibration target plate 300 at the calibration point to correct the target surface attitude in real time, thereby realizing full-condition calibration and calibration of multiple positions and multiple attitudes, which greatly improves the calibration accuracy and the coverage of calibration conditions.

[0025] In this embodiment, the linkage includes a first gear 701 and a second gear 702. The first gear 701 is disposed between the shaft end of the drive gear 503 and the drive motor 502, and the second gear 702 is disposed at the end of the worm 602. The first gear 701 and the second gear 702 mesh with each other. The displacement component includes an electric push rod 700, which is fixedly connected to one end of the interior of the movable base 501, and its output end is connected to the drive motor 502, which is slidably mounted on the inside of the movable base 501.

[0026] The anti-detachment component includes an arc-shaped limiting groove 901 symmetrically opened at both ends of the inner side of the arc-shaped groove and two arc-shaped limiting blocks 900 symmetrically arranged at the rotating end of the rotating frame 601. The arc-shaped limiting blocks 900 are slidably fitted in the arc-shaped limiting groove 901.

[0027] It is worth noting that the arc-shaped limiting block 900 and the arc-shaped limiting groove 901 work together to form an axial anti-detachment guide structure. On the one hand, it is used to limit the axial movement of the rotating frame 601 along the arc-shaped groove, prevent the rotating frame 601 from falling out of the arc-shaped groove of the positioning seat 600, and ensure the connection reliability of the calibration target plate 300. On the other hand, it provides circumferential guidance and stroke limit for the deflection movement of the rotating frame 601, ensuring the smooth movement of the calibration target plate 300 during the deflection adjustment process and avoiding excessive deflection that could cause structural interference.

[0028] In another specific embodiment of the present invention, reference is made to Figure 6 , Figure 8 , Figure 9 and Figure 10 It is known that the drive mechanism also includes a limiting component, which includes a pressure block 800 and a second loop guide groove 801. The second loop guide groove 801 is opened in the support base 400 and located outside the first loop guide groove 401. The pressure block 800 is slidably assembled in the second loop guide groove 801. The end of the guide post 504 extends into the second loop guide groove 801 and is connected to the pressure block 800. When switching working modes, when the drive gear 503 moves away from the stop post 402 and the linkage engages, the pressure block 800 moves axially synchronously with the guide post 504 and presses against the adjacent groove walls of the second guide groove 801 and the first guide groove 401. The pressure block 800 is made of rubber elastic material, which produces elastic deformation after being pressed and fits tightly against the groove wall contact surface. By increasing the static friction between the contact surfaces, the moving frame 500 is restricted from sliding laterally along the support base 400, thereby preventing the calibration target plate 300 from moving horizontally and ensuring the positional stability of the calibration reference during the target attitude adjustment stage.

[0029] Working principle: Select the initial installation height of the device according to the requirements. Fixture the calibration target plate 300 onto the test sample side and initially align it with the fixture. Initially, the displacement component controls the drive gear 503 to mesh with the stop post 402, and the linkage component disengages. At this time, the drive motor 502, through the cooperation of the drive gear 503 and the stop post 402, can drive the calibration target plate 300 to move. The movement path can sequentially complete a complete loop motion according to trajectory a, trajectory b, trajectory c, and trajectory d. During calibration, calibration points with different object distances can be obtained at the same gauge length height, and calibration points with different gauge lengths can be obtained at the same object distance. The calibration points are set at the specified degrees, and the calibration points can be started and stopped at any position on the loop trajectory according to the calibration requirements. The calibration process is completed automatically and continuously under multiple working conditions. During this process, the displacement component can control the drive gear 503 to move and disengage from the stop column 402. The linkage component completes the engagement transmission synchronously. At this time, the drive motor 502 is driven by the linkage component and the worm gear 603 to make the rotating frame 601 deflect along the axis of the arc groove, adjust the target surface tilt angle of the calibration target plate 300, keep the target surface parallel to the imaging plane of the camera, and correct the target surface attitude in real time to realize multi-position and multi-attitude full working condition calibration.

[0030] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0031] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A non-contact extensometer calibration device, characterized in that, The device includes an extensometer body (100) with a camera, a fixing fixture, a posture correction unit, and a calibration target plate (300). The posture correction unit is connected between the fixing fixture and the calibration target plate (300). The calibration target plate (300) has a calibration dot array (301) arranged on the surface facing the camera. The calibration target plate (300) and the posture correction unit are mounted on the sample testing side of the extensometer body (100) through the fixing fixture. The posture correction unit includes a support base (400), a movable frame (500), a movable seat (501), a deflection adjustment mechanism, and a drive mechanism; The movable seat (501) is fixed on the fixed fixture and has a U-shaped guide groove (401) on it. The movable frame (500) slides laterally on the support seat (400). The movable seat (501) slides longitudinally on the movable frame (500). The deflection adjustment mechanism is set between the movable seat (501) and the calibration target plate (300) for adjusting the target surface attitude of the calibration target plate (300). The driving mechanism is disposed between the movable seat (501) and the support seat (400), and is configured to drive the movable frame (500) to reciprocate along the horizontal direction of the sample, and to drive the movable seat (501) to reciprocate along the axial direction of the sample, so as to drive the calibration target plate (300) to move along the loop trajectory.

2. The non-contact extensometer calibration device according to claim 1, characterized in that, One end of the movable frame (500) is slidably sleeved on the support base (400). A sliding assembly is provided between the movable base (501) and the movable frame (500). The sliding assembly includes a T-shaped groove (5011) and a T-shaped slider (5012). The T-shaped slider (5012) is fixedly connected to the end of the movable base (501). The T-shaped groove (5011) is opened on the inner side of the movable frame (500), and the T-shaped slider (5012) slides in cooperation with the T-shaped groove (5011).

3. The non-contact extensometer calibration device according to claim 1, characterized in that, The drive mechanism includes several stop posts (402), a drive motor (502), drive teeth (503), and guide posts (504). The drive motor (502) is installed inside the movable seat (501), and its output end is connected to the drive tooth (503). The drive tooth (503) is located on one side of the loop guide groove (401). Several of the stop posts (402) are arranged at intervals along the extension direction of the loop guide groove (401) on the side wall of the support seat (400), and the drive tooth (503) meshes with each stop post (402) in sequence. The guide post (504) is coaxially disposed at the shaft end of the drive tooth (503), and the guide post (504) is slidably embedded in the spiral guide groove (401).

4. The non-contact extensometer calibration device according to claim 3, characterized in that, The deflection adjustment mechanism includes a positioning seat (600), a rotating frame (601), a transmission component, an anti-detachment component, and a linkage mechanism; The positioning seat (600) is fixedly connected to the movable seat (501), and its end is provided with an arc-shaped groove. The rotating frame (601) is rotatably connected to the arc-shaped groove through an anti-detachment component, and it is fixedly connected to the calibration target plate (300). The transmission component includes a worm (602), a worm wheel (603), and a transmission rod. The worm (602) is rotatably connected to the inner cavity of the positioning seat (600), the transmission rod is disposed in the inner cavity of the rotating frame (601), and the worm wheel (603) is disposed on the transmission rod, and the worm wheel (603) meshes with the worm (602). The linkage mechanism includes a linkage component and a displacement component. The displacement component is configured to drive the drive motor (502) and drive teeth (503) to move, so as to switch the meshing state of the drive teeth (503) and the stop column (402). When the drive tooth (503) disengages from the stop post (402), the linkage engages, and the drive motor (502) drives the worm gear (602) to rotate via the linkage. When the drive tooth (503) meshes with the stop post (402), the linkage disengages, and the drive motor (502) drives the calibration target plate (300) to move along a loop trajectory through the cooperation of the drive tooth (503) and the stop post (402).

5. The non-contact extensometer calibration device according to claim 4, characterized in that, The anti-detachment component includes an arc-shaped limiting groove (901) symmetrically opened at both ends of the inner side of the arc-shaped groove and two arc-shaped limiting blocks (900) symmetrically arranged at the rotating end of the rotating frame (601). The arc-shaped limiting blocks (900) are slidably fitted in the arc-shaped limiting groove (901).

6. The non-contact extensometer calibration device according to claim 4, characterized in that, The linkage includes a first gear (701) and a second gear (702). The first gear (701) is disposed between the shaft end of the drive gear (503) and the drive motor (502). The second gear (702) is disposed at the end of the worm (602). The first gear (701) and the second gear (702) mesh with each other. The displacement component includes an electric push rod (700), which is fixedly connected to one end of the interior of the movable seat (501), and its output end is connected to a drive motor (502), which is slidably mounted on the inside of the movable seat (501).

7. The non-contact extensometer calibration device according to claim 4, characterized in that, It also includes a limiting component, which includes a pressure block (800) and a second spiral guide groove (801). The second spiral guide groove (801) is opened in the support base (400) and located outside the first spiral guide groove (401). The pressure block (800) is slidably assembled in the second spiral guide groove (801). The end of the guide post (504) extends into the second spiral guide groove (801) and is connected to the pressure block (800). When the drive tooth (503) moves away from the stop post (402) and the linkage engages, the pressure block (800) moves synchronously with the guide post (504) and presses against the groove between the groove of the second guide groove (801) and the first guide groove (401).

8. The non-contact extensometer calibration device according to claim 1, characterized in that, The fixed fixture includes a fixed base (200), two sets of L-shaped clamps (201) and two sets of hydraulic rods (202). The two sets of hydraulic rods (202) are symmetrically arranged at both ends of the fixed base (200), and the output ends of the two sets of hydraulic rods (202) are symmetrically provided with connecting seats (203). The two connecting seats (203) are fixedly connected to the two sets of L-shaped clamps (201) respectively, and at least one set of telescopic rods is provided between the connecting seats (203) and the fixed base (200). Rubber anti-slip pads are provided on the inner side of the two sets of L-shaped clamps (201).

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