Vibrating element measuring device

Abstract

This application provides a vibration element measurement device, comprising: a laser assembly for illuminating the test area of ​​the vibration element under test, wherein the surface of the vibration element under test located in the test area is provided with speckle patterns; two camera assemblies, respectively arranged on both sides of the test area of ​​the vibration element under test, for capturing speckle images of the vibration element under test during its movement; and a gimbal, on which the two camera assemblies are mounted, the gimbal being used for off-axis focusing of the camera assemblies. By arranging the two camera assemblies on both sides of the test area of ​​the vibration element under test and using the gimbal for off-axis focusing, the two camera assemblies can achieve full-field focusing of the test area of ​​the vibration element under test, thereby acquiring clear speckle images of each speckle pattern, thus achieving accurate measurement of the three-dimensional displacement and / or strain of the vibration element under test.

Description

Technical Field

[0001] This application relates to the field of testing equipment technology, and in particular to a vibration element measuring device. Background Technology

[0002] Vibrating elements inside electronic components (such as the spring steel plates inside a linear vibration motor) often need to generate certain movements according to design requirements to achieve specific functions. Therefore, the reliability of vibrating elements is a crucial factor affecting product quality. Reliable measurement of the displacement and / or strain of vibrating elements during vibration is necessary to facilitate subsequent product quality optimization. In particular, due to the three-dimensional nature of motion and the three-dimensional appearance of the vibrating elements themselves (such as deformation), image-based measurement must also consider three-dimensional measurement capabilities.

[0003] Currently, when using speckle technology combined with digital image correlation (DIC) to measure the displacement and / or strain of vibrating elements that are undergoing internal motion deformation in electronic components, there is a problem of the acquired speckle images being out of focus at the edges and unclear, resulting in inaccurate measurements of the three-dimensional displacement and / or strain of the vibrating elements. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a vibration element measuring device that can solve the problem of inaccurate three-dimensional displacement and / or strain measurements of vibration elements in existing methods.

[0005] This application provides a vibration element measuring device, comprising: a laser assembly for illuminating the test area of ​​the vibration element to be tested, wherein the surface of the vibration element to be tested located in the test area is provided with particle speckle; two camera assemblies, respectively arranged on both sides of the test area of ​​the vibration element to be tested, for capturing particle speckle images of the vibration element to be tested during its movement; and a gimbal, wherein the two camera assemblies are mounted on the gimbal, and the gimbal is used for off-axis focusing of the camera assemblies.

[0006] The vibration element measuring device provided in this application, by placing two camera assemblies on both sides of the test area of ​​the vibration element to be measured, and using a gimbal to perform off-axis focusing on the two camera assemblies, achieves full-field focusing of the test area of ​​the vibration element to be measured by the two camera assemblies, thereby enabling the acquisition of particle speckle images with clear speckle patterns of each particle, thereby achieving accurate measurement of the three-dimensional displacement and / or strain of the vibration element to be measured.

[0007] In some possible implementations, the laser assembly includes a laser and a laser beam expander; the laser beam expander is located at the end of the laser head of the laser and is used to expand the point beam laser emitted by the laser into a sheet-like laser. The arrangement of the laser beam expander diffuses the point beam laser into a sheet-like laser, ensuring that the laser can cover the dimensions of the vibrating element under test in the length or width direction.

[0008] In some possible implementations, the laser beam expander is a cylindrical lens or a Powell prism. This can make the intensity distribution of the laser beam on the sheet relatively uniform, thereby uniformly illuminating the speckle pattern in the area to be measured and avoiding problems such as measurement errors or inconsistent processing results caused by uneven light intensity.

[0009] In some possible implementations, the thickness of the sheet-like laser covers the test area of ​​the vibrating element during its movement. In this way, the sheet-like laser can consistently illuminate the test area of ​​the vibrating element during its movement, ensuring that the camera assembly can capture the particle speckle pattern across the entire test area.

[0010] In some possible implementations, the thickness of the sheet-like laser ranges from 1 mm to 5 mm. For thin-layer vibrating elements, while ensuring that the sheet-like laser can always illuminate the test area of ​​the vibrating element, the energy of the sheet-like laser is made more concentrated, i.e., the light intensity is greater, thereby ensuring that the particle speckle in the test area can be clearly imaged.

[0011] In some possible implementations, the depth-of-field range of the camera component lies within the thickness range of the sheet-like laser. Therefore, the depth-of-field range of the camera component in this application is much smaller than the depth-of-field calibration distance of conventional DIC, effectively ensuring the accuracy of the depth-of-field calculation. Furthermore, by reducing the calibration range of the depth-of-field direction, the problem of excessively large depth-of-field range and inaccurate measurement when using traditional DIC technology for strain or displacement side profiles is improved.

[0012] In some possible implementations, the camera assembly includes a camera and a lens, which are mounted independently on a gimbal; the gimbal is used to adjust the angle between the camera's imaging plane and the lens's lens plane, as well as the distance between the camera and the lens.

[0013] In some possible implementations, with the vibrating element under test positioned at the measurement location, for each camera assembly, the camera imaging plane, the lens plane, and the plane containing the vibrating element under test intersect on the same straight line. This setup follows Scham's theorem, resulting in a clear image in the depth of field, thereby improving measurement accuracy.

[0014] In some possible implementations, the gimbal includes a base, a tilt-shift bracket, a first displacement adjustment mechanism, and an angle adjustment mechanism; the tilt-shift bracket is fixed on the base, the first displacement adjustment mechanism is movably mounted on the base, and the angle adjustment mechanism is rotatably mounted on the first displacement adjustment mechanism; the lens is fixed on the tilt-shift bracket, and the camera is fixed on the angle adjustment mechanism.

[0015] In some possible implementations, the gimbal also includes a second displacement adjustment mechanism. This second displacement adjustment mechanism is movably mounted on the base and positioned opposite to the first displacement adjustment mechanism. This second displacement adjustment mechanism is used to adjust the distance between the camera assembly and the vibration element under test. By adjusting the distance between the camera assembly and the vibration element under test, and in conjunction with adjusting the lens focal length, the length of the vibration element under test can be made to essentially fill the entire length of the camera frame. Therefore, while ensuring that the entire test area of ​​the vibration element is captured, more pixels can be used to represent the unit distance, improving spatial resolution and resulting in higher accuracy in spatial calibration, thereby improving measurement accuracy.

[0016] In some possible implementations, the gimbal includes a first gimbal and a second gimbal, and the two camera components include a first camera component and a second camera component, with the first camera component mounted on the first gimbal and the second camera component mounted on the second gimbal.

[0017] In some possible implementations, the first and second gimbals are symmetrically positioned on either side of the measurement location of the vibrating element under test, and the camera imaging planes and lens planes of the two camera assemblies are symmetrically distributed on either side of the measurement location of the vibrating element under test. This arrangement follows Schahm's theorem, enabling clear imaging of particle speckle patterns on curved surfaces.

[0018] In some possible implementations, the laser component includes a laser, and the camera component includes a camera; the laser is a pulsed laser, and the camera is a multi-frame camera. This avoids image trailing. Simultaneously, the pulsed laser emits a short-pulse-width laser with high power, which better illuminates the speckle pattern, allowing the camera to capture high-contrast speckle images.

[0019] In some possible implementations, the vibration element measuring device also includes a synchronizer, which is electrically connected to the laser and the camera respectively, for controlling the laser and the camera to work synchronously.

[0020] In some possible implementations, the camera component includes a lens; the lens is a DSLR camera lens.

[0021] In some possible implementations, the laser component includes a laser, and the camera component includes a camera; the laser is a continuous laser, and the camera is a multi-frame camera operating in single-frame mode. This setup avoids image trailing in the second frame. It should be noted that the laser emitted by the continuous laser should have sufficiently high power to enable the camera to capture high-contrast speckle images. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the structure of a particle speckle image acquisition device, as an example.

[0023] Figure 2 This is a schematic diagram of the structure of a vibration element measuring device provided in an embodiment of this application;

[0024] Figure 3 This is a schematic diagram of a gimbal structure provided in an embodiment of this application. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0027] The terms "first" and "second," etc., used in the specification and claims of this application are used to distinguish different objects, not to describe a specific order of objects. For example, "first target object" and "second target object," etc., are used to distinguish different target objects, not to describe a specific order of target objects.

[0028] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0029] In the description of the embodiments in this application, unless otherwise stated, "multiple" means two or more. For example, multiple processing units means two or more processing units; multiple systems means two or more systems.

[0030] Currently, when using particle speckle technology combined with DIC technology to measure the displacement and / or strain of vibrating elements within electronic components undergoing internal motion deformation, situations arise where the vibrating element is not an ideal plane but a curved surface. Furthermore, the motion deformation of the vibrating element also exhibits certain three-dimensional effects and high-frequency characteristics (for example, the forced vibration frequency of the spring steel sheet inside a linear vibration motor is 150–200 Hz). In such cases, ordinary DIC technology based on a monocular industrial camera cannot effectively measure the three-dimensional displacement and / or strain of three-dimensional curved surface components. Meanwhile, binocular industrial cameras (with frame rates typically between 30 and 60 fps) lack dynamic measurement capabilities, have insufficient frequency response, and are prone to image trailing when the measured component's motion frequency is high, affecting measurement accuracy.

[0031] Figure 1 A schematic diagram of a particle speckle image acquisition device is shown as an example. (Refer to...) Figure 1 As shown, the particle speckle image acquisition device includes two light sources 1, two industrial cameras 2, and a mounting base 3. Both the light sources 1 and the industrial cameras 2 are mounted on the mounting base 3. The two industrial cameras 2 are positioned at a certain angle, and the lens plane of each industrial camera 2 is parallel to the camera's imaging plane. When the vibration element experiences three-dimensional displacement and / or strain, because the aforementioned industrial cameras 2 can only perform off-axis imaging, only the particle speckle patterns located on the focal plane can be clearly imaged. This results in defocus blurring in the depth of field, affecting the accuracy of measuring the three-dimensional displacement and / or strain of the vibration element.

[0032] To address the problem of inaccurate measurement of three-dimensional displacement and / or strain of vibrating elements, this application provides a vibration element measuring device for measuring the vibration of internal electronic components in electronic devices, primarily measuring the displacement and / or strain of the vibration element. The aforementioned electronic devices include, but are not limited to, mobile phones, tablets, laptops, ultra-mobile personal computers (UMPCs), handheld computers, walkie-talkies, netbooks, POS machines, personal digital assistants (PDAs), dashcams, wearable devices (such as smartwatches and wristbands), or virtual reality devices, and other mobile or fixed electronic devices. These electronic devices include, but are not limited to, linear vibration motors, microsensors, or microactuators. For example, for linear vibration motors, the vibration element can be a spring steel sheet; for microsensors or microactuators, the vibration element can be an elastic metal film (e.g., a titanium alloy film). This application does not limit the type and structure of the vibration element; the specific choice depends on the actual situation.

[0033] In particular, the vibration element to be tested in this application is mainly a thin-layer vibration element, wherein the vibration element to be tested vibrates along its thickness direction, and its thickness can be from 0.1 nm to 0.5 nm.

[0034] See Figure 2 , Figure 2 This is a schematic diagram of the structure of a vibration element measuring device provided in an embodiment of this application. Figure 2 As shown, the vibration element measuring device includes a laser assembly 10 for illuminating the test area of ​​the vibration element 100 to be tested, wherein the surface of the vibration element 100 to be tested in the test area is provided with particle speckle 101; two camera assemblies 20 are respectively arranged on both sides of the test area of ​​the vibration element 100 to be tested, for capturing particle speckle images of the vibration element 100 to be tested during its movement; and a gimbal 30 on which the two camera assemblies 20 are mounted, the gimbal 30 being used for off-axis focusing of the camera assemblies 20.

[0035] In some embodiments, the laser assembly 10 includes a laser 11 and a laser beam expander 12; wherein the laser 11 includes a laser body 111, a light guide arm 112, and a laser head 113 connected in sequence. The laser body 111 generates laser energy, which is emitted as a point beam laser after passing through its internal optical resonant cavity. The point beam laser is conducted to the laser head 113 via the light guide arm 112 and emitted from the laser head. The laser beam expander 12 is located at the end of the laser head 113 of the laser 11 and is used to expand the point beam laser emitted by the laser 11 into a sheet-like laser 10a. The laser beam expander 12 diffuses the point beam laser at a certain angle in the length or width direction of the vibration element 100 under test, forming a sheet-like laser 10a, thereby ensuring that the laser can cover the dimensions of the vibration element 100 under test in the length or width direction. Meanwhile, the sheet-like laser 10a has a certain thickness perpendicular to the diffusion direction, which can cover the movable range of the test area of ​​the vibration element 100 under test. That is, the thickness range of the sheet-like laser 10a can cover the test area of ​​the vibration element 100 under test during its movement. In this way, during the movement of the vibration element 100 under test, the sheet-like laser 10a can always illuminate the test area of ​​the vibration element 100 under test, thereby ensuring that the camera assembly 20 can capture the particle speckle 101 of the entire test area.

[0036] For thin-layer vibrating elements, the displacement of their out-of-plane motion is generally small, for example, around 1 mm. Correspondingly, the thickness of the sheet-like laser can be from 1 mm to 5 mm. Therefore, while ensuring that the sheet-like laser 10a can always illuminate the test area of ​​the vibrating element 100, the energy of the sheet-like laser 10a is more concentrated, i.e., the light intensity is greater, thus ensuring that the speckle 101 of the test area can be clearly imaged. Furthermore, the depth-of-field range of the camera assembly 2 is within the thickness range of the sheet-like laser. For example, the depth-of-field range of the camera assembly 2 is 3 mm. Therefore, the depth-of-field range of the camera assembly 2 in this application is much smaller than the depth-of-field calibration distance of conventional DIC (a few centimeters to tens of centimeters), effectively ensuring the accuracy of the depth-of-field calculation. Thus, by reducing the calibration range of the depth-of-field direction, the problem of insufficient accuracy in measurement due to an excessively large depth-of-field range when using traditional DIC technology for strain or displacement measurements is improved.

[0037] Moreover, the light intensity distribution of the sheet laser 10a is relatively uniform, which can uniformly illuminate the particle speckle 101 of the area to be measured, avoiding problems such as measurement errors or inconsistent processing effects caused by uneven light intensity.

[0038] Optionally, the laser beam expander 12 can be a cylindrical lens or a Powell prism. With a Powell prism, the expanded sheet-like laser 10a is uniformly distributed in the diffusion direction. With a cylindrical lens, the expanded sheet-like laser 10a has a thickness distribution that is thicker at both ends and narrower in the middle in the diffusion direction. Therefore, the vibration element 100 to be tested can be positioned at the waist of the sheet-like laser 10a. This ensures both uniform light intensity distribution in the test area of ​​the vibration element 100 and a higher light intensity in the test area, guaranteeing that the speckle 101 in the test area can be clearly imaged.

[0039] In some embodiments, combined with Figure 2 and Figure 3 As shown, the camera assembly 2 includes a camera 201 and a lens 202, which are independently mounted on a gimbal 30. The gimbal 30 is used to adjust the angle between the camera imaging plane and the lens plane, as well as the distance between the camera 201 and the lens 202.

[0040] For example, the position and orientation of the camera assembly 2 can be calibrated using the gimbal 30 based on Schahm's theorem (see below for details). This involves calibrating the angle between the camera's imaging plane and the lens plane, as well as the distance between the camera 201 and the lens 202. This ensures that the camera's imaging plane, the lens plane, and the plane containing the vibration element under test intersect on the same straight line, thereby obtaining a clear image in the depth of field and improving measurement accuracy. Furthermore, in the initial state, the lens 202 is coaxial with the camera 201, with the center of the lens 202 directly opposite the center of the photosensitive plate of the camera 201.

[0041] It is understood that this application can obtain a clear image in the depth of field, enabling accurate measurement of the three-dimensional displacement and / or strain of the vibrating element under test. Similarly, this application can also achieve accurate measurement of the planar displacement and / or strain of the vibrating element under test.

[0042] Since the camera 201 and lens 202 are separate, the position and orientation of the camera 201 and / or lens 202 can be adjusted so that the angle between the camera's imaging plane and the lens plane, as well as the distance between the camera 201 and lens 202, follows Schahm's theorem. This application uses the gimbal 30 to adjust the position and orientation of the camera 201 as an example to illustrate the structure of the gimbal 30.

[0043] For example, such as Figure 3As shown, the gimbal includes a base 301, a tilt-shift bracket 302, a first displacement adjustment mechanism 303, and an angle adjustment mechanism 304. The tilt-shift bracket 302 is fixed on the base 301, the first displacement adjustment mechanism 303 is movably mounted on the base 301, and the angle adjustment mechanism 304 is rotatably mounted on the first displacement adjustment mechanism 303. The lens 202 is fixed on the tilt-shift bracket 302, and the camera 201 is fixed on the angle adjustment mechanism 304.

[0044] The aforementioned base 301 and tilt-shift bracket 302 can be integrally formed to achieve relative fixation between the tilt-shift bracket 302 and the base 301. Alternatively, the base 301 and tilt-shift bracket 302 can be installed separately, with the tilt-shift bracket 302 mounted on the base 301. A lens adapter ring can be mounted on the tilt-shift bracket 302, and the lens 202 is mounted within the lens adapter ring.

[0045] The first displacement adjustment mechanism 303 is capable of linear movement (relative to the base 301) in the direction of approaching and moving away from the tilt-shift bracket 302. For example, a guide rail is provided on the surface of the base 301 facing the first displacement adjustment mechanism 303, and the first displacement adjustment mechanism 303 is mounted on the guide rail and can move linearly along it. The first displacement adjustment mechanism 303 has a raised step plate in the middle, and a rotatable angle adjustment mechanism 304 is fixedly connected to the upper surface of the step plate. A mounting base is provided on the upper surface of the angle adjustment mechanism 304, and the camera 201 is mounted in the mounting base. Thus, by moving the first displacement adjustment mechanism 303, the angle adjustment mechanism 304 can be moved, thereby moving the camera 201 closer to or further away from the lens 202, achieving adjustment of the distance between the camera 201 and the lens 202. By rotating the angle adjustment mechanism 304, the camera 201 can be rotated, thereby changing the angle between the photosensitive plate of the camera 201 and the lens 202, achieving adjustment of the angle between the camera's imaging plane and the lens plane.

[0046] Based on the above embodiments, the gimbal may further include a second displacement adjustment mechanism (not shown in the figure). The second displacement adjustment mechanism is movably disposed on the base and is disposed opposite to the first displacement adjustment mechanism. The second displacement adjustment mechanism is used to adjust the distance between the camera assembly and the vibration element to be measured.

[0047] For example, the base includes a first surface and a second surface opposite to each other. A first displacement adjustment mechanism is disposed on the first surface, and a second displacement adjustment mechanism is disposed on the second surface. Similarly, a guide rail can be disposed on the second surface, and the second displacement adjustment mechanism is mounted on the guide rail. Moving the second displacement adjustment mechanism on the guide rail can cause the camera assembly to move towards or away from the vibration element under test, thereby adjusting the distance between the camera assembly and the vibration element under test. By adjusting the distance between the camera assembly and the vibration element under test, and in conjunction with adjusting the lens focal length, the size of the vibration element under test in the length direction can be made to essentially fill the length of the camera frame. Therefore, while ensuring that the entire test area of ​​the vibration element under test is captured, more pixels can be used to characterize a unit distance (e.g., 1 mm), improving spatial resolution and resulting in higher spatial calibration accuracy, thereby improving measurement accuracy.

[0048] In some embodiments, such as Figure 2 As shown, the gimbal 30 includes a first gimbal 31 and a second gimbal 32, and the two camera assemblies 20 include a first camera assembly 21 and a second camera assembly 22. The first camera assembly 21 is mounted on the first gimbal 31, and the second camera assembly 22 is mounted on the second gimbal 32. Thus, the first camera assembly 21 and the second camera assembly 22 can be controlled independently through their respective gimbals.

[0049] In some embodiments, see continue to see Figure 2 The first gimbal 31 and the second gimbal 32 are symmetrically arranged on both sides of the measurement position of the vibration element 100 under test. The camera imaging planes and lens planes of the two camera assemblies 30 are also symmetrically distributed on both sides of the measurement position of the vibration element 100 under test. This arrangement can follow the Schahm theorem to achieve clear imaging of particle speckle on the curved surface.

[0050] In some embodiments, the laser is a pulsed laser and the camera is a cross-frame camera.

[0051] Considering that when the laser is a continuous laser, its on / off state needs to be controlled by a switch. However, when a multi-frame camera captures images, the shutter response time is faster for the first frame and slower for the second, and the vibrating element under test is typically placed in a dark environment. When capturing the second frame, the laser will turn off first, while the camera shutter remains open, resulting in image trailing in the second frame. Therefore, this application uses a pulsed laser. Thus, when the laser emits a laser pulse, the camera shutter opens, and when the laser pulse closes, the camera shutter closes, thus avoiding image trailing. Simultaneously, the pulsed laser emits a short-pulse-width laser with higher power, which can better illuminate the speckle pattern, allowing the camera to capture high-contrast speckle images.

[0052] In addition, when the vibrating element under test has the characteristic of high-frequency vibration, the laser can be a high-speed pulsed laser and the camera can be a high-frequency cross-frame camera. By combining the high-speed pulsed laser with the high-frequency cross-frame camera, dynamic measurement of the displacement and / or strain of the high-frequency vibrating element can be realized.

[0053] For pulsed lasers and multi-frame cameras, see the corresponding documentation. Figure 2 The vibration element measuring device also includes a synchronizer 40, which is electrically connected to the laser 11 and the camera 201 respectively, and is used to control the laser 11 and the camera 201 to work synchronously. For example, the synchronizer 40 sends a synchronization signal to the laser 11 and the camera 201 to trigger the laser 11 and the camera 201 to work synchronously.

[0054] Furthermore, when the multi-frame camera operates in single-frame mode, the laser can also be a continuous laser. In this case, as long as the shutter response speed is maintained when the multi-frame camera captures the first frame, image trailing in the second frame can be avoided. It should be noted that the laser emitted by the continuous laser should have sufficiently high power to enable the camera to capture high-contrast speckle images.

[0055] In some embodiments, the camera component includes a lens; the lens is a single-lens reflex camera lens.

[0056] It should be noted that the lens in this application is not limited to SLR camera lenses, as long as the captured image does not exhibit significant image distortion.

[0057] The above describes the specific structure of the vibration element measuring device. The following section, based on... Figure 2 The vibration element measuring device shown herein describes the measurement process of the vibration element measuring device of this application.

[0058] Preparation: Configure the vibration element to be tested and assemble the vibration element measuring device.

[0059] For example, particle speckle patterns are pre-fabricated on the surface of the vibrating element under test. The vibrating element measures 3mm x 8mm, has a thickness of 0.1mm, and a motion frequency of 170Hz. Two high-frequency cross-frame cameras are mounted on a gimbal. The high-speed cross-frame camera has a full-frame size of 2048 pixels x 2048 pixels, a sampling frequency of 1000Hz, and a shutter speed adjustable to a minimum of 1μs. A 70-180mm telephoto lens is used for the SLR camera, also mounted on the gimbal, with the lens aperture set to its maximum. A synchronizer is connected to the high-speed cross-frame camera and the high-frequency pulsed laser via a coaxial BNC cable. The synchronizer's trigger signal delay resolution is 250ps, the laser's single-pulse energy is 30mJ@1000Hz, the laser pulse width is 150ns@1000Hz, the spot laser beam diameter is 5mm, and after beam expansion by a cylindrical lens, the sheet-like laser beam angle is 15°, resulting in a sheet-like laser beam thickness of 3-5mm.

[0060] Calibration work: Calibration of lenses for high-speed multi-frame cameras and SLR cameras based on Schahm's theorem. The following combines... Figure 2 The calibration steps are described below. In the first camera assembly 21, camera 201 is a first high-speed cross-frame camera and lens 202 is a first SLR camera lens; in the second camera assembly 22, camera 201 is a second high-speed cross-frame camera and lens 202 is a second SLR camera lens.

[0061] a. Place a spatial calibration plate at the test position of the vibration element to be tested, and place the first gimbal 31 and the second gimbal 32 symmetrically on both sides of the test position of the vibration element to be tested 100.

[0062] b. The camera imaging plane M1 of the first high-speed cross-frame camera is parallel to the lens plane N1 of the first SLR camera lens. The lens plane N1 of the first SLR camera lens makes an angle of approximately 45° with the plane O1 where the space calibration plate is located.

[0063] c. The camera imaging plane M2 of the second high-speed cross-frame camera is parallel to the lens plane N2 of the second SLR camera lens. The lens plane N2 of the second SLR camera lens makes an angle of approximately -45° with the plane O1 where the space calibration plate is located.

[0064] d. Observe the first gimbal 31 and the second gimbal 32 respectively, and adjust the positions of the first gimbal 31 and the second gimbal 32 until the focus area of ​​the first gimbal 31 and the second gimbal 32 is the same very small area at the center of the space calibration plate.

[0065] e. Adjust (either manually or automatically) the angle adjustment mechanism 304 of the first gimbal 31. The angle adjustment mechanism 304 rotates, thereby changing the angle of the camera imaging plane M1 of the first high-speed cross-frame camera while keeping the plane O1 of the space calibration plate and the lens plane N1 of the first SLR camera lens unchanged. Continuously observe the real-time shooting image of the first high-speed cross-frame camera. As the optical path system gradually approaches the off-axis focusing principle, it will be observed that the focused area in the image captured by the first high-speed cross-frame camera gradually changes from a very small area at the center of the space calibration plate. Gradually expand to the left and right sides until the entire spatial calibration plate (or the test area of ​​the spatial calibration plate corresponding to the vibration element under test) is in focus, indicating that the off-axis focusing angle adjustment of the first gimbal 31 is complete. Then finely adjust the focusing ring of the first SLR camera lens and the distance between the first SLR camera lens and the spatial calibration plate until the image captured by the first high-speed cross-frame camera reaches the optimal focus state. At this time, the lens plane N1 of the first SLR camera lens, the camera imaging plane M1 of the first high-speed cross-frame camera and the plane O1 where the spatial calibration plate is located intersect at the intersection line L1 located in the normal direction.

[0066] f. Repeat step e to adjust the second gimbal 32 until the image captured by the second high-speed cross-frame camera reaches the optimal focus state. At this time, the lens plane N2 of the second SLR camera lens, the camera imaging plane M2 of the second high-speed cross-frame camera, and the plane O1 of the space calibration plate intersect at the intersection line L2 located in the normal direction.

[0067] Measurement work: capture particle speckle images of the vibrating element under test, and calculate the displacement and / or strain of the vibrating element under test based on DIC technology.

[0068] For example, the vibrating element under test is returned to the measurement position. The electronic components of the vibrating element under test are controlled to operate, causing the vibrating element to undergo motion deformation. The synchronizer controls the operation of the high-speed cross-frame camera and the high-frequency pulsed laser to capture and record particle speckle images.

[0069] Export and save the recorded speckle image, perform DIC analysis, and calculate the displacement and / or strain of the vibrating element under test. Specifically, the speckle image is divided into sub-regions, which are usually small square or rectangular areas. The size and shape of these sub-regions affect the accuracy and efficiency of the calculation. Generally, the smaller the sub-region, the higher the calculation accuracy, but the greater the computational cost. For each sub-region, a correlation algorithm is used to find the region that best matches it in the deformed speckle image. A commonly used correlation algorithm is the Normalized Cross-Correlation (NCC) algorithm. The displacement of the vibrating element under test can then be calculated. Since strain is the derivative of displacement, the strain of the vibrating element under test can be obtained by differentiating the displacement. Specifically, in a two-dimensional plane problem, the displacement has u x and u y The strain is represented by three components: ε xx ε yy and γ xy Their relationship with displacement is as follows:

[0070] It represents linear strain in the x-direction, that is, the elongation or shortening per unit length in the x-direction.

[0071] This represents the linear strain in the y-direction.

[0072] It represents the shear strain in the xy plane, reflecting the angular changes of the object in that plane.

[0073] In three-dimensional space, displacement can be represented as u x u y and u z The strain tensor has three components, while the strain tensor has six independent components, of which the linear strain component is ε. xx ε yy and ε zz The shear strain component is γ xy γ yz and γ zx Their relationship with displacement is as follows:

[0074]

[0075] Finally, disconnect the power supply to all electrical equipment, remove the vibration element under test, and store it in the designated location.

[0076] It should be noted that if the vibration element under test can be driven independently, only the vibration element under test needs to be placed at the measurement position. Otherwise, the electronic component to which the vibration element under test belongs should be placed at the measurement position, and a window should be opened on the electronic component to illuminate and photograph the vibration element under test inside the electronic component with laser.

[0077] In summary, the vibration element measuring device provided in this application provides a method to accurately measure the three-dimensional displacement and / or strain of the vibration element by placing two camera assemblies on both sides of the test area of ​​the vibration element under test and using a gimbal to perform off-axis focusing on the two camera assemblies. This allows the two camera assemblies to achieve full-field focusing on the test area of ​​the vibration element under test, thereby acquiring clear speckle images of each speckle pattern.

[0078] Any content in the various embodiments of this application, as well as any content in the same embodiment, can be freely combined. Any combination of the above content is within the scope of this application.

[0079] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A vibration element measuring device, characterized in that, include: A laser assembly is used to illuminate the test area of ​​a vibration element under test, wherein the surface of the vibration element under test located in the test area is provided with particle speckle. Two camera assemblies are respectively arranged on both sides of the test area of ​​the vibration element under test, and are used to capture particle speckle images of the vibration element under test during its motion. A gimbal, on which two camera components are mounted, the gimbal being used for off-axis focusing of the camera components.

2. The vibration element measuring device according to claim 1, characterized in that, The laser assembly includes a laser and a laser beam expander; The laser beam expander is placed at the end of the laser head of the laser and is used to expand the point beam laser emitted by the laser into a sheet-like surface laser.

3. The vibration element measuring device according to claim 2, characterized in that, The laser beam expander is a cylindrical lens or a Powell prism.

4. The vibration element measuring device according to claim 2, characterized in that, The thickness range of the sheet-like laser covers the test area of ​​the vibrating element under test during its movement.

5. The vibration element measuring device according to claim 4, wherein the thickness of the sheet-like laser is 1 mm to 5 mm.

6. The vibration element measuring device according to claim 4, characterized in that, The depth-of-field range of the camera assembly is within the thickness range of the sheet-like laser.

7. The vibration element measuring device according to claim 1, characterized in that, The camera assembly includes a camera and a lens, which are independently mounted on the gimbal. The gimbal is used to adjust the angle between the camera's imaging plane and the lens's lens plane, as well as the distance between the camera and the lens.

8. The vibration element measuring device according to claim 7, characterized in that, When the vibration element under test is placed in the measurement position, for each camera assembly, the camera imaging plane, the lens plane, and the plane where the vibration element under test is located intersect on the same straight line.

9. The vibration element measuring device according to claim 7, characterized in that, The gimbal includes a base, a tilt-shift bracket, a first displacement adjustment mechanism, and an angle adjustment mechanism; The shifting bracket is fixed on the base, the first displacement adjustment mechanism is movably mounted on the base, and the angle adjustment mechanism is rotatably mounted on the first displacement adjustment mechanism; The lens is fixed on the tilt-shift bracket, and the camera is fixed on the angle adjustment mechanism.

10. The vibration element measuring device according to claim 9, characterized in that, The gimbal also includes a second displacement adjustment mechanism, which is movably mounted on the base and is positioned opposite to the first displacement adjustment mechanism. The second displacement adjustment mechanism is used to adjust the distance between the camera assembly and the vibration element to be measured.

11. The vibration element measuring device according to claim 7, characterized in that, The gimbal includes a first gimbal and a second gimbal, and the two camera components include a first camera component and a second camera component. The first camera component is mounted on the first gimbal, and the second camera component is mounted on the second gimbal.

12. The vibration element measuring device according to claim 11, characterized in that, The first gimbal and the second gimbal are symmetrically arranged on both sides of the measurement position of the vibration element under test, and the camera imaging planes and lens planes of the two camera assemblies are symmetrically distributed on both sides of the measurement position of the vibration element under test.

13. The vibration element measuring device according to any one of claims 1-12, characterized in that, The laser assembly includes a laser, and the camera assembly includes a camera; The laser is a pulsed laser, and the camera is a cross-frame camera.

14. The vibration element measuring device according to claim 13, characterized in that, The vibration element measuring device also includes a synchronizer, which is electrically connected to the laser and the camera respectively, and is used to control the laser and the camera to work synchronously.

15. The vibration element measuring device according to claim 13, characterized in that, The camera assembly includes a lens; The lens in question is a DSLR camera lens.

16. The vibration element measuring device according to any one of claims 1-12, characterized in that, The laser assembly includes a laser, and the camera assembly includes a camera; The laser is a continuous laser, the camera is a cross-frame camera, and the camera operates in single-frame mode.

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