Micro-radian-level angle dynamic measurement device and method

Abstract

The embodiment of the invention discloses a micro-radian-level angle dynamic measurement device and method, and the device comprises a mechanical angle amplification unit which comprises a transmission gear set with the transmission ratio smaller than 1, an input shaft is used for connecting a measured object so as to achieve the synchronous angle change, and an output shaft is used for synchronously amplifying the angle change; the angle-displacement conversion unit comprises an angle-displacement conversion assembly used for converting the angle change amplified by the transmission gear set into linear displacement change, and a linear guide rail moving along with the linear displacement change; the interference image acquisition unit comprises a Michelson interference assembly and pattern acquisition equipment for acquiring a time sequence interference image set in real time, and a moving mirror M2 of the Michelson interference assembly is arranged on a linear guide rail; the interference image processing unit obtains angle change time sequence data of the measured object based on the time sequence interference image set. Michelson interference is expanded to angle measurement, and a micro-angle dynamic measurement scheme with high precision, stability and robustness is realized.

Description

Technical Field

[0001] Several embodiments in this specification relate to the field of precision optical measurement technology, specifically to the optimization of accuracy and stability in dynamic measurement of microradian-level angles. Background Technology

[0002] In scientific research fields such as precision manufacturing, optical engineering, and structural health monitoring, it is often necessary to measure minute angular changes on the order of microradians. Examples include precision optics and optical assembly, laboratory precision metrology and calibration, and industrial quality control and online inspection.

[0003] Currently, the main technical means to achieve small angle detection include the following categories: First, optical autocollimators, which calculate the angle by detecting the displacement of the reflected image on the reticle, suitable for static or quasi-static calibration; second, laser gyroscopes, which measure angular velocity based on the Sagnac effect and obtain the angle through integration, and are widely used in inertial navigation and other fields; and third, grating encoders, which read the moiré fringes of a rotating grating disk through photoelectric signals and perform interpolation counting, and are commonly used angle sensors in industrial servo systems.

[0004] However, optical autocollimators lack the ability to continuously and quantify dynamic measurements of angle changes, making them difficult to apply to process monitoring. Laser gyroscopes, essentially angular velocity sensors, exhibit decreased sensitivity when measuring extremely slow or quasi-static angle changes. Furthermore, their integration process accumulates noise and zero bias, resulting in significant integration drift and unreliable long-term monitoring results. Grating encoders, whose output is based on discrete counting and interpolation, suffer from low signal update rates, high noise levels, and significantly reduced resolution under extremely slow angle changes. They are also highly sensitive to mechanical assembly errors (such as eccentricity and runout), susceptible to vibration and contamination, complex to install, and have poor environmental adaptability. Therefore, none of these methods can achieve high-resolution, high-precision, and high-stability dynamic monitoring of minute angle changes. Summary of the Invention

[0005] This specification provides a device and method for dynamic measurement of micro-radian angles, which extends Michelson interferometry to angle measurement by integrating mechanical amplification, angle-displacement conversion, and AI visual recognition. This solves the problem of existing methods lacking a high-precision, high-stability dynamic measurement scheme for micro-radian angles.

[0006] The technical solution is as follows:

[0007] In a first aspect, the embodiments of this specification provide a microradian-level dynamic angle measurement device, including a mechanical angle amplification unit, an angle-to-displacement conversion unit, an interferometric image acquisition unit, and an interferometric image processing unit;

[0008] The mechanical angle magnification unit includes a transmission gear set, wherein the transmission ratio between the input shaft and the output shaft of the transmission gear set is less than 1, the input shaft is used to connect to the object under test to synchronously acquire the angle change of the object under test, and the output shaft synchronously magnifies the angle change;

[0009] The angle-displacement conversion unit includes a linear guide rail and an angle-displacement conversion component. The angle-displacement conversion component is used to convert the angle change amplified by the transmission gear set into a linear displacement change. The linear guide rail moves with the linear displacement change.

[0010] The interferometric image acquisition unit includes a Michelson interferometer component that converts displacement changes into optical path difference changes and a pattern acquisition device. The Michelson interferometer component includes a moving mirror M2 disposed on the linear guide rail. The pattern acquisition device acquires interferometric images in real time to obtain a time-series interferometric image set characterizing the optical path difference changes.

[0011] The interferometric image processing unit acquires time-series data of the angle change of the object under test based on the time-series interferometric image set.

[0012] As a preferred embodiment, the interference image processing unit includes a center spot detection module, a fringe change determination module, and a data processing module;

[0013] The center spot detection module obtains the center spot type and center spot area of ​​each interference image in the temporal interference image set based on a deep learning model.

[0014] The fringe change determination module determines the change in the number of interference fringes based on the center spot type and center spot area of ​​each of the adjacent interference images.

[0015] The data processing module obtains the time-series data of the angle change of the object under test based on the change in the number of interference fringes corresponding to each pair of adjacent interference images.

[0016] As a preferred embodiment, the central spot type includes bright spots and dark spots;

[0017] The fringe change determination module increments the number of interference fringes by one if the change in the center spot type of adjacent interference images changes from bright to dark, and the absolute value of the change in the area of ​​the corresponding center spot in each adjacent interference image is greater than a preset threshold; otherwise, the number of interference fringes remains unchanged.

[0018] When the center spot type of adjacent interference images changes from dark spot to bright spot, and the absolute value of the change in the center spot area of ​​each adjacent interference image is greater than a preset threshold, if the change in the center spot area is positive, the number of interference fringes decreases by one; if the change in the center spot area is negative, the number of interference fringes remains unchanged.

[0019] As a preferred embodiment, the transmission gear set includes multiple coaxially arranged planetary gear acceleration components, wherein the planet carrier of the primary planetary gear acceleration component is the input shaft, and the sun gear of the final planetary gear acceleration component is the output shaft.

[0020] As a preferred embodiment, the angle-displacement conversion component includes a helical cam coaxially arranged with the sun gear of the final-stage planetary gear acceleration component;

[0021] The linear guide rail is provided with a rolling bearing whose axial direction is perpendicular to the length direction of the linear guide rail and parallel to the output shaft of the transmission gear set, and a reset traction member that applies a driving force from the rolling bearing to the helical cam, so that the side wall of the rolling bearing abuts against the side wall of the helical cam.

[0022] As a preferred embodiment, a magnetic coupling transmission mechanism is provided between the moving mirror M2 and the linear guide rail;

[0023] The magnetic coupling transmission mechanism includes an anti-gravity suspension component, an upper magnet, and a lower magnet disposed on the top of the linear guide rail and having the opposite polarity to the upper magnet. The upper magnet and the lower magnet are disposed opposite to each other.

[0024] The anti-gravity levitation assembly includes a magnetic track fixedly positioned above the linear guide rail and aligned with the length direction of the linear guide rail, and a magnetic frame surrounding the magnetic track and movable along the length direction of the magnetic track. The upper end face of the magnetic frame is connected to the moving mirror M2, and the lower end face is connected to the upper magnet. The magnetic track provides the magnetic frame with anti-gravity and a horizontal balancing force perpendicular to the length direction of the magnetic track, so that the magnetic frame is in a stable levitation state and the upper magnet and the lower magnet maintain a fixed gap.

[0025] As a preferred embodiment, the upper end face of the magnetic track is provided with two symmetrically arranged permanent magnet arrays along its own length direction;

[0026] The top inner side of the magnetic frame is provided with multiple electromagnetic units corresponding to the two permanent magnet arrays, and the bottom inner side of the magnetic frame is provided with multiple staggered displacement sensors to obtain the attitude information of the magnetic frame.

[0027] The antigravity levitation assembly also includes an attitude controller that controls the magnitude of the electromagnetic force generated by each of the electromagnetic units based on attitude information.

[0028] Secondly, embodiments of this specification provide a method for dynamic measurement of microradian-level angles. Based on the dynamic angle measurement device described in the first aspect of the above embodiments, the dynamic measurement method includes the following steps:

[0029] Acquire the transmission ratio between the input and output shafts of the transmission gear set, the angle-to-displacement conversion coefficient of the angle-to-displacement conversion component, the incident light wavelength of the Michelson interferometer component, and the time-series interference image set;

[0030] The time-series data of the angle change of the object under test are obtained based on the transmission ratio, angle-displacement conversion coefficient, incident light wavelength and time-series interferometric image set.

[0031] As a preferred embodiment, the step of acquiring the time-series data of the angle change of the object under test based on the transmission ratio, angle-displacement conversion coefficient, incident light wavelength, and time-series interferometric image set includes:

[0032] The center spot type and center spot area of ​​each interference image are obtained based on the temporal interferometric image set;

[0033] The change in the number of interference fringes is determined based on the type and area of ​​the center spot corresponding to each of the adjacent interference images.

[0034] The time-series data of the angle change of the object under test are obtained based on the changes in transmission ratio, angle-displacement conversion coefficient, incident light wavelength, and the number of interference fringes corresponding to each pair of adjacent interference images.

[0035] As a preferred embodiment, the step of determining the change in the number of interference fringes based on the center spot type and center spot area of ​​each adjacent interference image includes:

[0036] When the center spot type of adjacent interference images changes from bright spot to dark spot, and the absolute value of the change in the area of ​​the corresponding center spot in each adjacent interference image is greater than a preset threshold;

[0037] If the change in the area of ​​the central spot is negative, the number of interference fringes increases by one;

[0038] If the change in the area of ​​the central spot is positive, the number of interference fringes remains unchanged;

[0039] When the center spot type of adjacent interference images changes from dark spot to bright spot, and the absolute value of the change in the area of ​​the corresponding center spot in each adjacent interference image is greater than a preset threshold;

[0040] If the change in the area of ​​the central spot is positive, the number of interference fringes decreases by one.

[0041] If the change in the area of ​​the central spot is negative, the number of interference fringes remains unchanged.

[0042] Thirdly, embodiments of this specification provide an electronic device, including a processor and a memory; the processor is connected to the memory; the memory is used to store executable program code; the processor reads the executable program code stored in the memory to run a program corresponding to the executable program code, so as to perform the steps described in the second aspect of the above embodiments.

[0043] Fourthly, embodiments of this specification provide a computer storage medium storing a plurality of instructions adapted for loading by a processor and executing the steps described in the second aspect of the above embodiments.

[0044] The beneficial effects of the technical solutions provided in some embodiments of this specification include at least the following:

[0045] An integrated high-precision measurement chain encompassing "angle magnification, displacement conversion, optical interferometry, and visual recognition" has been constructed. Through systematic unit collaboration, direct, dynamic, and high-resolution measurement of minute angle changes at the microradian level has been achieved. Unaffected by the static range of grating encoders or gyroscope drift, it can be used for online real-time monitoring and long-term trend measurement.

[0046] The method of directly measuring displacement instead of integrating angular velocity maintains high stability and eliminates integral drift even under quasi-static, small velocity angular changes. This fundamentally avoids the integral drift problem present in technologies such as laser gyroscopes when measuring extremely slow, quasi-static angle changes, ensuring stability for long-term monitoring.

[0047] The magnetic coupling transmission mechanism achieves physical isolation between the drive end and the optical measurement end. Combined with an active magnetic levitation anti-gravity attitude control system, a closed-loop "sensing-decision-execution" process ensures that the plane mirror M2 frame maintains a stable suspension height and horizontal attitude throughout its movement. This reduces vibration interference and creates an extremely stable environment for interferometric measurements.

[0048] Instead of the traditional method of identifying the entire fringe ring, this approach uses a deep learning model to directly identify bright / dark spots at the center of the interference pattern. This method offers higher tolerance to interference from illumination fluctuations, fringe breaks, and image noise, while improving counting accuracy. It replaces the subjective and fatigue-prone manual counting methods, as well as the less robust traditional image processing algorithms, achieving fully automated and highly reliable fringe recognition and counting. Its accuracy is significantly superior to that of grating encoders based on discrete counting and traditional interferometry methods that rely on manual interpretation.

[0049] Compared to expensive autocollimators / laser gyroscopes, this device has a simpler structure, significantly reducing manufacturing costs. Its modular design facilitates calibration, maintenance, and upgrades, making it more suitable for educational demonstrations and industrial field deployments. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a schematic diagram of the overall structure of a microradian-level dynamic angle measuring device provided in Embodiment 1 of this specification (the Michelson interferometer component and pattern acquisition device are not shown).

[0052] Figure 2 This is a schematic diagram showing the complete structure and principle of the Michelson interferometer component in a microradian-level dynamic angle measurement device provided in Embodiment 1 of this specification.

[0053] Figure 3 This is a schematic diagram of the structure of the interferometric image processing unit in a microradian-level dynamic angle measurement device provided in Embodiment 1 of this specification.

[0054] Figure 4 This is a schematic diagram of the overall structure of a micro-radian-level dynamic angle measuring device provided in Embodiment 1 of this specification, showing the specific arrangement of the planetary gear acceleration assembly, linear guide rail, and angle-displacement conversion assembly.

[0055] Figure 5 This is a partial structural side view of a micro-radian-level dynamic angle measuring device provided in Embodiment 1 of this specification, showing the anti-gravity suspension component, the upper magnet, and the lower magnet.

[0056] Figure 6 This is a partial structural schematic diagram of a micro-radian-level angle dynamic measurement device provided in Embodiment 1 of this specification, showing the specific arrangement of the anti-gravity suspension component.

[0057] Figure 7 This is a flowchart illustrating a dynamic angle measurement method at the microradian level provided in Embodiment 2 of this specification.

[0058] Figure 8 This is a schematic diagram of the structure of an electronic device provided in Embodiment 3 of this specification.

[0059] In the diagram, 1. Transmission gear set; 11. Input shaft; 12. Output shaft; 13. Planetary gear acceleration assembly; 131. Planet carrier; 132. Sun gear; 133. Planetary gear; 134. Fixed gear ring; 2. Linear guide rail; 21. Rolling bearing; 22. Reset traction component; 3. Angle-displacement conversion assembly; 31. Helical cam; 4. Moving mirror M2; 5. Interference image processing unit; 51. Center spot detection module; 52. Stripe change determination module; 53. Data processing module; 6. Magnetic coupling transmission mechanism; 61. Anti-gravity suspension assembly; 62. Upper magnet; 63. Lower magnet; 611. Magnetic track; 6111. Permanent magnet array; 6112. Soft magnetic return circuit structure; 612. Magnetic frame; 6121. Electromagnetic unit; 6122. Displacement sensor. Detailed Implementation

[0060] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings.

[0061] The terms "first," "second," "third," etc., in the description, claims, and accompanying drawings are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0062] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the described elements without departing from the scope of this specification. Various processes or components may be appropriately omitted, substituted, or added to the examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Furthermore, features described with respect to some examples may be combined into other examples.

[0063] Existing technologies (such as optical autocollimators, laser gyroscopes, and grating encoders) each have fundamental defects that are difficult to overcome when it comes to achieving dynamic measurement of minute angles, making it impossible to achieve a balance between accuracy, stability, cost, and ease of use.

[0064] Autocollimators can quickly provide static angle readings, but require good reflectivity of the measured reflective surface and stable support to achieve high repeatability. They are suitable for mechanical assembly, mirror collimation, and static calibration. However, they cannot dynamically record and visualize the same minute angular changes in a time series format, which limits their applicability in dynamic teaching, continuous process monitoring, or online testing scenarios requiring time resolution.

[0065] Laser gyroscopes obtain angles by measuring and integrating angular velocities. When measuring extremely slow, quasi-static, minute angle changes (near-zero angular velocity), their sensitivity decreases, and the integration process accumulates noise and zero bias, producing significant "integration drift," which leads to unreliable long-term monitoring results.

[0066] Optical encoders, based on the principle of "discrete counting + interpolation," have low signal update rates, high noise levels, and reduced resolution under extremely slow changes. Furthermore, they are highly sensitive to mechanical assembly errors (such as eccentricity and runout), easily affected by vibration and contamination, and are complex to install with poor environmental adaptability.

[0067] Therefore, this solution is proposed.

[0068] Example 1

[0069] A microradian-level dynamic angle measurement device

[0070] like Figure 1 As shown, Figure 1 This is a schematic diagram of the overall structure of a microradian-level dynamic angle measuring device provided in Embodiment 1 of this specification (the Michelson interferometer component and pattern acquisition device are not shown).

[0071] The angle dynamic measurement device includes a mechanical angle amplification unit, an angle-to-displacement conversion unit, an interferometric image acquisition unit, and an interferometric image processing unit 5;

[0072] The mechanical angle magnification unit includes a transmission gear set 1. The transmission ratio between the input shaft 11 and the output shaft 12 of the transmission gear set 1 is less than 1. The input shaft 11 is used to connect to the object under test to synchronously acquire the angle change of the object under test, and the output shaft 12 synchronously magnifies the angle change.

[0073] Angle-displacement conversion unit includes a linear guide rail 2 and an angle-displacement conversion component 3. The angle-displacement conversion component 3 is used to convert the angle change amplified by the transmission gear set 1 into a linear displacement change. The linear guide rail 2 moves with the linear displacement change.

[0074] The interferometric image acquisition unit includes a Michelson interferometer component that converts displacement changes into optical path difference changes and a pattern acquisition device. The Michelson interferometer component includes a moving mirror M24 mounted on a linear guide rail 2. The pattern acquisition device acquires interferometric images in real time to obtain a time-series interferometric image set characterizing the optical path difference changes.

[0075] Interference image processing unit 5 acquires time-series data of the angle change of the object under test based on a time-series interference image set.

[0076] This embodiment constructs an integrated high-precision measurement chain encompassing "angle magnification, displacement conversion, optical interferometry, and visual recognition." Through systematic unit collaboration, this device achieves direct, dynamic, and high-resolution measurement of minute angular changes.

[0077] Specifically, the core of the mechanical angle amplification unit is the transmission gear set 1, whose transmission ratio between the input shaft 11 and the output shaft 12 is less than 1, meaning that the rotational speed of the output shaft 12 will be higher than that of the input shaft 11. A multi-stage nested gear structure with parallel axes can be adopted.

[0078] The mechanical angle amplification unit significantly amplifies the minute angular displacement of the input shaft 11 through a high acceleration ratio. That is, when the input shaft 11 rotates by a small angle, the output shaft 12 rotates synchronously by an amplified angle. This significantly improves the ability of subsequent measurement stages to detect minute angular changes.

[0079] The amplified angular displacement is converted into an observable linear displacement by an angle-to-displacement conversion unit. This unit contains at least one linear guide 2 and an angle-to-displacement conversion component 3. The angle-to-displacement conversion component 3 linearly converts the rotational motion of the output shaft 12 into the axial displacement of the linear guide 2, thereby converting the angular change into a definite physical displacement.

[0080] The angle-displacement conversion component 3 can use common gear and rack mechanisms, crank-slider mechanisms, or helical pairs of nuts and ball screws to achieve angle-displacement conversion, converting rotational motion into axial linear displacement, and driving the moving mirror M24 to produce corresponding linear displacement.

[0081] Linear displacement changes are measured with high precision by the interferometric image acquisition unit. For example... Figure 2 As shown, Figure 2This is a schematic diagram illustrating the complete structure and principle of the Michelson interferometer component in a micro-radian-level dynamic angle measurement device provided in Embodiment 1 of this specification. The core of this unit is the Michelson interferometer component, which includes a He-Ne laser, a beam splitter, a fixed plane mirror M1, a moving mirror M24 mounted on a linear guide rail 2, and a compensation plate. Its basic principle is as follows: the light emitted by the He-Ne laser is split into two beams by the beam splitter, which are directed towards M1 and M2 respectively, and interfere upon reflection. When the moving mirror M24 moves with the guide rail, the optical path difference between the two beams changes accordingly, forming alternating bright and dark interference fringes on the observation screen. A pattern acquisition device (such as an industrial camera, for example, with a camera resolution ≥1280×720 and a frame rate ≥60fps; the lens focal length and aperture are configured according to the distance to the experimental platform to ensure fringe clarity and ring number ≥50) acquires the interference images on the observation screen in real time, forming a time-series interference image set. The change in optical path difference manifests as the "swallowing" and "spitting out" of interference fringes in the pattern. For every λ / 2 distance the moving mirror M24 moves, the optical path difference changes by one wavelength λ, resulting in a corresponding "swallowing" or "spitting out" of an interference fringe in the field of view. The relationship between the displacement Δδ of the moving mirror M24 and the number of changes in the interference fringes is: Δδ = N × (λ / 2), where N is the number of fringe movements and λ is the laser wavelength (632.8 nm). A traditional Michelson interferometer is a device that measures nanoscale displacements using the principle of optical path interference. This device uses a Michelson interferometer component as the sensitive unit, which uses monochromatic coherent light to generate concentric interference fringes on the observation screen. Through a displacement-angle conversion mechanism, the measurement range of the Michelson interferometer is extended from displacement to angle, broadening the application range of this traditional instrument.

[0082] Finally, the interferometric image processing unit 5, based on the acquired time-series interferometric image set, employs two traditional counting methods: one is to manually count the number of interference fringes N frame by frame; the other is to use classical image processing methods on the acquired images: first, denoise the interferometric images, perform threshold segmentation, extract the fringe contours using edge detection, and finally, use fringe centerline extraction technology and Hough transform to perform circle / arc fitting in the parameter space to automatically identify and count the number of interference fringes N. Substituting N into the above formula and combining it with parameters such as the mechanical amplification factor of the transmission gear set 1 and the conversion rate of the angle-to-displacement conversion component 3, the time-series data of the dynamic angle change of the measured object can be calculated.

[0083] In summary, this embodiment converts a minute input angle into a larger linear displacement through high-magnification mechanical amplification, then uses a Michelson interferometer to perform nanometer-precision optical measurement of this displacement, and finally completes signal processing through intelligent vision algorithms. This method is a scheme that directly measures displacement rather than integrating angular velocity, which can fundamentally avoid integration errors and ensure long-term stability under quasi-static measurement. It provides a new and reliable integrated solution for achieving high-precision dynamic measurement of microradian angles.

[0084] Additionally, for objects under test with rigid rotation axes, the planetary carrier 131 input shaft 11 can be directly and rigidly connected. Applicable scenarios include precision optics and optical assembly, laboratory precision metrology, and machine tool spindle calibration. Specifically, for small mirror tilt angle calibration and fine-tuning of telescopes / optical stages, the lenses / spectral splitters of medium to large-sized telescopes or optical stages are often fine-tuned via support shafts or rotating supports; these supports typically have clamping adjustment shafts. The support shaft of the mirror under test is coaxially and rigidly connected to the planetary gear 133 input shaft 11.

[0085] For disc-shaped or disk-shaped objects that cannot or are not suitable for rigid couplings, rotary magnetic coupling (magnetic ring) can be used for transmission. Applicable scenarios include optical platforms requiring non-contact, sealed, and vibration-isolated operation; situations where structural monitoring cannot damage components; and industrial sites requiring dust and pollution prevention. Specifically, this could be a large reflective disk (adjustable mirror within a sealed cavity) inside a sealed optical cavity / vacuum chamber. For certain optical components (large reflectors or adjustable reflective disks) located in a vacuum or airtight cavity, where shafts or rigid exposed connections are not possible, a ring of rare-earth permanent magnets is pasted or bonded to the outer circumference of the disk (forming a first magnetic ring). A second magnetic ring (driven) is installed outside the cavity on the measuring module and coupled to the input shaft 11 of the planetary carrier 131. Magnetic coupling can transmit angular changes non-contactly, but torque is limited. When the measured object experiences transient high torque or severe impact, relative slippage (decoupling) may occur. If the application requires withstanding large impacts, mechanical limits or bypass rigid connections must be considered in the design.

[0086] In one embodiment of this specification, such as Figure 3 As shown, Figure 3 This is a schematic diagram of the structure of the interferometric image processing unit 5 in a microradian-level dynamic angle measurement device provided in Embodiment 1 of this specification. The interferometric image processing unit 5 includes a center spot detection module 51, a fringe change determination module 52, and a data processing module 53;

[0087] The center spot detection module 51 obtains the center spot type and center spot area of ​​each interference image in the temporal interference image set based on a deep learning model;

[0088] The fringe change determination module 52 determines the change in the number of interference fringes based on the type and area of ​​the center spot corresponding to each of the adjacent interference images.

[0089] The data processing module 53 acquires the time-series data of the angle change of the object under test based on the change in the number of interference fringes corresponding to each pair of adjacent interference images.

[0090] This embodiment employs a robust automatic interference fringe counting scheme based on AI vision. It abandons the traditional approach of identifying the entire interference ring, instead using deep learning target detection technology to directly focus on the most prominent bright / dark spots at the center of the interference image, and achieves accurate counting by analyzing their dynamic changes.

[0091] In this embodiment, the deep learning model is a lightweight YOLOv8 customized target detection model trained on nearly 2,000 manually annotated interference images (including bright spot / dark spot boundary labels). In addition, the weight allocation of the loss function is improved to address the blurred edge characteristics of interference images, which effectively improves the detection accuracy of the model for low-contrast spots.

[0092] The center spot detection module 51, based on this deep learning model, first initially locates the central region of the interference ring, then crops the dynamic region to focus on key feature areas to reduce redundant computation. It quickly and accurately identifies and locates the central bright or dark spot in each frame of the interference image, and outputs its center spot type (bright / dark) and pixel area. This method of directly detecting high-contrast spot regions is more stable and faster than traditional methods that identify the entire fringe ring or perform edge detection, and is more robust to image noise, slight defocus, or fringe distortion.

[0093] The stripe change determination module 52 does not simply count the number of spots, but determines a valid "swallowing" or "spitting" event based on the dynamic changes in the type and area of ​​spots in adjacent frames. Its determination rule combines information from two dimensions: image features (spot type) and quantized changes (area), making it more reliable than a single judgment condition.

[0094] The data processing module 53 receives the increase / decrease sequence of the number of stripes N output by the stripe change determination module 52, and converts the number of stripes N into the angle change of the measured object according to the pre-calibrated calculation model, thereby obtaining the time sequence data of the angle change of the measured object and realizing the continuous measurement of dynamic angle.

[0095] This embodiment establishes a complete automated processing chain through a three-level processing flow: center spot detection, dynamic change determination, and data conversion. It transforms complex visual judgments into quantifiable data analysis and intelligent decision-making. The optimized interference image processing unit 5 can be deployed on embedded platforms such as Raspberry Pi, and the quantized and compressed deep learning model can achieve real-time detection at 25fps on a Raspberry Pi 4B platform. Ultimately, it achieves high-precision and high-stability interference fringe counting, providing a reliable data source for the entire micro-angle measurement device.

[0096] As a supplement, grayscale normalization and Gaussian filtering can be performed on each interferometric image in the temporal interferometric image set. Grayscale normalization converts the color image into a single-channel grayscale image and normalizes the brightness range to [0,1]; Gaussian filtering uses a Gaussian kernel with σ=1.5 to smooth the image and eliminate high-frequency noise interference.

[0097] In one embodiment of this specification, the center spot type includes a bright spot and a dark spot;

[0098] The fringe change determination module 52 determines the number of interference fringes by incrementing it if the change in the center spot type of adjacent interference images changes from bright to dark, and the absolute value of the change in the center spot area of ​​each adjacent interference image is greater than a preset threshold. If the change in the center spot area is negative, the number of interference fringes remains unchanged.

[0099] When the center spot type of adjacent interference images changes from dark spot to bright spot, and the absolute value of the change in the center spot area of ​​each adjacent interference image is greater than a preset threshold, if the change in the center spot area is positive, the number of interference fringes decreases by one; if the change in the center spot area is negative, the number of interference fringes remains unchanged.

[0100] This embodiment clarifies how to accurately determine a valid "swallowing" or "spitting" event based on the direction and magnitude of the center spot type switching and area change in adjacent frames, thereby ensuring the accuracy and robustness of the counting.

[0101] Explained, a complete ring-forming process involves a bright spot enlarging, forming a ring, then a dark spot forming, followed by the dark spot enlarging again and forming a new bright spot. The bright spot-dark spot transition is the ring-forming operation to be identified and counted, while the dark spot-new bright spot transition is an intermediate process. Similarly, a complete ring-swallowing process involves a dark spot shrinking, the ring closing to form a bright spot, then the bright spot shrinking again and disappearing to form a dark spot. The dark spot-bright spot transition is the ring-swallowing operation to be identified and counted, while the bright spot-dark spot transition is an intermediate process. Intermediate processes should not be counted as changes in the number of interference fringes. The determination method in this embodiment is not simply detecting changes in spot type, but rather coupling type changes with the magnitude and direction of area changes to intelligently distinguish valid counting events from invalid intermediate processes or transient disturbances.

[0102] For example, the preset threshold is 40%. If the first two interferometric images show a bright spot of 80% size and a dark spot of 10% size respectively, and the absolute value of the change in the central spot area is 10% - 80% = -70%, then the absolute value is greater than the preset threshold and the change is negative, indicating that a ring-breaking operation has occurred, and the number of interference fringes increases by one. If the first two interferometric images show a dark spot of 80% size and a bright spot of 10% size respectively, and the absolute value of the change in the central spot area is 10% - 80% = -70%, then the absolute value is greater than the preset threshold and the change is negative, indicating that the intermediate process of ring-breaking has occurred, and the number of interference fringes remains unchanged. If the two consecutive interference images show a dark spot of 10% size and a bright spot of 80% size respectively, and the absolute value of the change in the area of ​​the central spot is 80%-10%=70%, and the absolute value is greater than the preset threshold and the change is positive, then it indicates that a ring swallowing operation has occurred, and the number of interference fringes decreases by one; if the two consecutive interference images show a bright spot of 10% size and a dark spot of 80% size respectively, and the absolute value of the change in the area of ​​the central spot is 80%-10%=70%, and the absolute value is greater than the preset threshold and the change is positive, then it indicates that an intermediate process of ring swallowing has occurred, and the number of interference fringes remains unchanged.

[0103] It should be noted that this solution is applied to scenarios with minute angle changes at the micro-radian level, where the rate of angle change fluctuations are small and relatively stable. Calibration can be performed before formal measurement, setting a preset threshold based on the maximum rate of angle change. Specifically: during the calibration phase, the relative area change rate threshold of the central spot areas corresponding to adjacent interferometric images is used to quickly adapt to the initial state; during the stable measurement phase, the threshold is switched to the absolute area change based on the maximum central spot area. Simultaneously, techniques such as temporal filtering can be introduced to distinguish between real fringe changes and transient disturbances, ensuring the accuracy of the count.

[0104] In one embodiment of this specification, such as Figure 4 As shown, Figure 4 This is a schematic diagram of the overall structure of a micro-radian-level dynamic angle measuring device provided in Embodiment 1 of this specification, showing the specific arrangement of the planetary gear acceleration assembly 13, the linear guide rail 2, and the angle-displacement conversion assembly 3.

[0105] The transmission gear set 1 includes multiple coaxially arranged planetary gear acceleration components 13, wherein the planet carrier 131 of the primary planetary gear acceleration component 13 is the input shaft 11, and the sun gear 132 of the final planetary gear acceleration component 13 is the output shaft 12.

[0106] This embodiment clarifies the specific configuration of the transmission gear set 1 using a multi-stage coaxial planetary gear 133 assembly and defines the power transmission path (input from the primary planetary carrier 131, output from the final stage sun gear 132). It is a highly efficient and compact structure designed to achieve a large acceleration ratio.

[0107] Because this device requires an extremely high acceleration ratio, using common parallel-shaft cylindrical gears in a multi-stage nested configuration would result in a less compact structure and excessively long axial dimensions. More importantly, due to the large acceleration ratio of multi-stage reduction gears, a small angular input may require a huge torque to drive the entire gear set. This places excessively high demands on the material strength of the angular input end and the performance of the drive motor, which would severely limit the application range of this device in low-torque drive scenarios.

[0108] Therefore, this embodiment uses a multi-stage coaxial planetary gear set 133 as the core acceleration mechanism. Exemplarily, it includes a three-stage coaxially mounted planetary gear acceleration assembly 13. Each planetary gear acceleration assembly 13 includes a planet carrier 131, a sun gear 132, multiple planet gears, and a fixed gear ring 134. The power of the object being measured is input from the planet carrier 131 of the first-stage planetary gear acceleration assembly 13, output from the sun gear 132 to the planet carrier 131 of the second-stage planetary gear acceleration assembly 13, then transmitted from the sun gear 132 of the second-stage planetary gear acceleration assembly 13 to the planet carrier 131 of the third-stage planetary gear acceleration assembly 13, and finally output from the sun gear 132 of the third-stage planetary gear acceleration assembly 13. The acceleration ratios of the three-stage planetary gear acceleration assemblies 13 are set to 1:10, 1:4, and 1:3, respectively. The single-stage acceleration ratio is typically 3–10, and the total acceleration ratio is: 1:10 × 4 × 3 = 120, that is, input 0.001°, output 0.12°.

[0109] The multi-stage coaxial design achieves a high acceleration ratio within a limited space, amplifying the rotation of the input shaft 11 before outputting it. The overall structure is compact and highly coaxial, effectively ensuring angular synchronization and stability during transmission. While amplifying angular displacement, multiple planetary gears simultaneously mesh with the sun gear 132, resulting in a smaller load on each gear. This effectively overcomes the lag and idle travel problems that may occur in traditional multi-stage nested gear structures when transmitting small angles.

[0110] Additionally, all stages of the planetary gear acceleration assembly 13 are manufactured using precision grinding technology to ensure coaxiality ≤0.01mm. Combined with preloaded bearings and a high-rigidity housing structure, the overall backlash is controlled within ≤5 arcmin, ensuring no significant lag or idle travel during angular displacement transmission, making it suitable for applications requiring high dynamic response and high positioning accuracy. Furthermore, it was verified that there was no jamming under static load and temperature rise was controlled (temperature rise <15°C after 30 minutes of no-load slow operation). Due to the large acceleration ratio of the multi-stage coaxial planetary gear set 133, driving the gear set with angular input may require extremely high torque, placing high demands on the material of the angular input end and limiting the application range of this device. Therefore, ball bearings can be used for each planetary gear to significantly reduce transmission resistance and improve transmission efficiency.

[0111] In one embodiment of this specification, such as Figure 4 As shown, the angle-displacement conversion assembly 3 includes a spiral cam 31 coaxially arranged with the sun gear 132 of the final stage planetary gear acceleration assembly 13;

[0112] The linear guide 2 is provided with a rolling bearing 21 whose axial direction is perpendicular to the length direction of the linear guide 2 and parallel to the output shaft 12 of the transmission gear set 1, and a reset traction member 22 that applies a driving force from the rolling bearing 21 to the helical cam 31, so that the side wall of the rolling bearing 21 abuts against the side wall of the helical cam 31.

[0113] This embodiment clarifies the specific implementation of the angle-to-displacement conversion unit using a helical cam 31 abutting against a rolling bearing 21, as well as the reset traction component 22 to ensure stable contact. Together, these achieve high-precision and high-stability angle-to-displacement conversion.

[0114] The angle-displacement conversion assembly 3 includes a helical cam 31 coaxially mounted with the sun gear 132 of the final-stage planetary gear acceleration assembly 13. This coaxial direct connection avoids additional transmission chains and reduces errors and backlash that may be introduced by intermediate links. Compared to traditional conversion methods such as rack and pinion mechanisms, crank-slider mechanisms, or helical pairs of nuts and ball screws, the Archimedean helical cam 31 used in this solution has the advantage of allowing for custom design of the "conversion coefficient" of the helical cam 31 profile. This allows for flexible amplification of specific small input angles into sufficiently large linear displacements required for optical measurement, which is difficult to achieve with standard linear elements such as lead screws due to their fixed pitch. Through comparative testing, high-density acrylic sheet was determined to be the optimal material for the helical cam 31, reducing errors by 62% compared to wood.

[0115] To ensure the smoothness and accuracy of the motion between the helical cam 31 and the follower, a rolling bearing 21 is installed on the linear guide 2 to effectively reduce the rotational friction of the helical cam 31. For example, using a P5 grade rolling bearing 21 can reduce the frictional force from approximately 0.5N to 0.05N, significantly improving displacement accuracy. The profile of the helical cam 31 is an Archimedean spiral, with a design conversion factor of 18mm / rad, ensuring that the number of interference fringes is within a reasonable range (50-150 rings).

[0116] The bearing's axial direction is perpendicular to the length of the linear guide 2 and parallel to the output shaft 12 of the transmission gear set 1. The reset traction element 22 (such as a spring, pneumatic rod, or other elastic telescopic element) continuously applies a reset driving force from the rolling bearing 21 to the helical cam 31 to the linear guide 2. This ensures that the sidewall of the rolling bearing 21 is always in close contact with the sidewall of the helical cam 31, effectively eliminating gaps during movement. This allows any rotation of the helical cam 31 to be converted into precise axial displacement of the bearing without delay or idle travel, thereby causing the connected linear guide 2 to drive the moving mirror M24 to undergo displacement changes. This provides high-quality variable input for subsequent interferometric measurements.

[0117] As a supplement, the spiral cam 31 is machined using a CNC milling machine or a precision lathe with a contour error ≤0.02mm; after machining, it is polished and the contour is measured (using a contour comparator or contour projection).

[0118] It should be noted that the input angle change of the measured object after magnification is still small, and the rotation range of the helical cam 31 is limited. After setting a suitable initial contact point, there is no need to worry about interference between the rolling bearing 21 and the radial drop of the helical cam 31.

[0119] In one embodiment of this specification, such as Figure 5 As shown, Figure 5 This is a partial structural side view of a micro-radian-level dynamic angle measuring device provided in Embodiment 1 of this specification, showing the anti-gravity suspension component 61, the upper magnet 62, and the lower magnet 63.

[0120] A magnetic coupling transmission mechanism 6 is provided between the moving mirror M24 and the linear guide rail 2;

[0121] The magnetic coupling transmission mechanism 6 includes an anti-gravity suspension component 61, an upper magnet 62, and a lower magnet 63 disposed on the top of the linear guide rail 2 and having the opposite polarity to the upper magnet 62. The upper magnet 62 and the lower magnet 63 are disposed opposite to each other.

[0122] The antigravity levitation assembly 61 includes a magnetic track 611 fixedly positioned above the linear guide rail 2 and aligned with the length direction of the linear guide rail 2, and a magnetic frame 612 surrounding the magnetic track 611 and movable along the length direction of the magnetic track 611. The upper end face of the magnetic frame 612 is connected to the moving mirror M24, and the lower end face is connected to the upper magnet 62. The magnetic track 611 provides the magnetic frame 612 with antigravity and a horizontal balancing force perpendicular to the length direction of the magnetic track 611, so that the magnetic frame 612 is in a stable levitation state and the upper magnet 62 and the lower magnet 63 maintain a fixed gap.

[0123] This embodiment achieves completely physically isolated, non-contact continuous displacement transmission through a magnetic coupling transmission mechanism 6 installed between the moving mirror M24 and the linear guide rail 2. This fundamentally eliminates the inherent friction, impact, and backlash in mechanical transmission, providing an extremely stable optical environment for interferometric measurements.

[0124] Specifically, in the magnetic coupling transmission mechanism 6, the upper magnet 62 and the lower magnet 63 are opposite poles (e.g., using neodymium iron boron N52 / N42 permanent magnet material), achieving non-contact displacement traction through magnetic attraction. When the helical cam 31 drives the linear guide rail 2 to move, the lower magnet 63 moves accordingly, and the upper magnet 62 above it and the entire magnetic frame 612 are "pulled" and moved synchronously under the action of magnetic force. The displacement transmission is entirely completed through the magnetic field.

[0125] To ensure the stability of this contactless transmission, the anti-gravity levitation component 61 in the magnetic coupling transmission mechanism 6 includes a fixed magnetic track 611, located above and parallel to the linear guide rail 2, and a magnetic frame 612 that can move along the magnetic track 611. By designing a precise magnetic field on the magnetic track 611 and the magnetic frame 612, the magnetic track 611 provides an upward anti-gravity force to the magnetic frame 612 to counteract its own weight and the magnetic attraction force of the upper magnet 62 and the lower magnet 63, while simultaneously providing a horizontal balancing force perpendicular to the track direction. This ensures that the magnetic frame 612 is in a stable levitation state, maintaining a fixed gap between the upper and lower magnets 63 at all times.

[0126] The magnetic coupling transmission mechanism 6 completely isolates the moving mirror M24 in the Michelson interferometer assembly from the outside world by floating, which greatly reduces the frequency of image disturbance and thus significantly improves the robustness and long-term stability of the device in dynamic measurement of small angles.

[0127] As an additional measure, a safety limiting plate should be installed on the side of the linear guide 2 near the lower magnet 63 to prevent the guide from being pulled out by the spring.

[0128] For example, in the anti-gravity levitation assembly 61, to achieve a horizontal balancing force perpendicular to the track direction and ensure that the plane mirror frame moves only along the guide rail axis (X direction) without lateral drift in the levitation state, a lateral passive magnetic array can be set. A stable lateral restoring force is provided by symmetrically arranging permanent magnet arrays 6111 on both sides of the magnetic track 611 and the inner side of the magnetic frame 612, thanks to the inherent repulsive force between the magnets. On the left and right side walls of the magnetic track 611, long strip-shaped track-side magnetic arrays are installed, each array consisting of multiple neodymium iron boron permanent magnets (10mm × 4mm × 2mm) arranged in a magnetic tape-like pattern with 2mm intervals. The magnetization direction of these magnets is uniformly set to face the magnetic frame 612 side with the same pole. Correspondingly, frame-side magnetic arrays are symmetrically arranged on the inner walls of the left and right sides of the magnetic frame 612, using magnets of the same specifications, with two magnets installed on each side, arranged parallel to the track-side magnetic arrays at 6mm intervals. Their height centerline is strictly aligned with the track-side magnetic arrays, with the alignment deviation controlled within ±0.5mm. The magnetization direction of the track-side magnetic array is aligned with the same pole as the frame-side magnetic array. When the magnetic frame 612 shifts laterally due to a minor disturbance, the repulsive force between the like-pole magnets quickly pushes it back to its central equilibrium position, thus forming a passive, non-contact lateral restoring force. To significantly improve the efficiency and linearity of this passive restoring force, a soft magnetic return circuit structure 6112 can be installed on the back of each magnetic array. It uses electrical silicon steel sheets with a thickness of 0.30–0.35 mm, laid in 5–8 layers, with a total thickness of 1.75–2.8 mm. An insulating coating is retained between the layers to suppress eddy current losses. The return circuit sheet covers the entire magnetic pole region along the length of the magnetic array and extends 3–5 mm at both ends to reduce edge flux leakage. To completely suppress large-scale eddy currents, the return circuit is segmented and broken every 30–50 mm along its length. The entire soft magnetic return circuit structure 6112 is installed using insulating pads and non-magnetic fasteners, maintaining an assembly air gap of 1–5 mm between it and the magnetic strip. The soft magnetic return circuit structure 6112 can effectively guide the magnetic flux closure, significantly reducing the magnetic circuit resistance, thereby generating a stronger and more linear restoring force under the same offset, enhancing the stability of attitude control.

[0129] In one embodiment of this specification, such as Figure 6 As shown, Figure 6 This is a partial structural schematic diagram of a micro-radian-level dynamic angle measuring device provided in Embodiment 1 of this specification, showing the specific arrangement of the anti-gravity suspension component 61.

[0130] Two symmetrical arrays of permanent magnets 6111 are arranged on the upper end face of the magnetic track 611 along its own length.

[0131] Multiple electromagnetic units 6121 corresponding to two permanent magnet arrays 6111 are provided on the top inner side of the magnetic frame 612, and multiple displacement sensors 6122 are provided on the bottom inner side of the magnetic frame 612 to obtain the attitude information of the magnetic frame 612.

[0132] The antigravity levitation component 61 also includes an attitude controller that controls the magnitude of the electromagnetic force generated by each electromagnetic unit 6121 based on attitude information.

[0133] This embodiment constructs a complete active attitude control system, which ensures that the plane mirror M2 frame maintains a stable suspension height and horizontal attitude during the movement through a closed loop of "perception-decision-execution".

[0134] Specifically, multiple electromagnetic units 6121 are arranged on the top inner side of the magnetic frame 612, corresponding to two permanent magnet arrays 6111 symmetrically arranged along their length on the upper surface of the magnetic track 611. Each electromagnetic unit 6121 consists of a pole face, a soft magnetic core (silicon steel / low-carbon iron laminations), and a coil. When energized, it generates a repulsive force with the permanent magnet array on the track, thus providing a controllable upward thrust. In this embodiment, the multiple electromagnetic units 6121 are arranged in a four-point rectangular layout to independently adjust the thrust at different positions of the frame, thereby controlling height and attitude (pitch, roll).

[0135] Multiple displacement sensors 6122 (such as eddy current sensors) are arranged in a staggered pattern at the bottom inner side of the magnetic frame 612. These sensors measure the instantaneous distance between multiple specific points on the frame and the reference plane of the track below in real time and at high frequency in a specific layout. In this embodiment, three displacement sensors 6122 are used, arranged in an equilateral triangle, and the instantaneous distance is denoted as (z1, z2, z3). The attitude controller receives the instantaneous distances from the displacement sensors 6122, first calculates the average value Z = (z1 + z2 + z3) / 3 to obtain the overall height, and then uses the three-point geometric relationship to calculate the current pitch angle and roll angle of the frame. The calculated actual height and angle are then compared with the preset target values ​​(such as target height g0 = 15.0 mm, target horizontal angle 0∘) to obtain the deviation. Based on the deviation, a PID or state feedback control algorithm is used to calculate the corrective force vector [F1, F2, F3] required to eliminate the deviation. Subsequently, based on the pre-calibrated "force-current-gap" mapping relationship, the force vector is converted into the current setting value required by each electromagnetic unit 6121, and the corresponding current is output to each electromagnetic unit 6121, thereby generating the required controllable electromagnetic force.

[0136] The displacement sensor 6122 senses the attitude in real time, the attitude controller intelligently decides on correction commands, and the electromagnetic unit 6121 precisely executes the output thrust. The three form a high-speed, continuous closed loop, dynamically maintaining the stable levitation of the frame. This ensures that the interferometric measurement optical path is not affected by mechanical vibration and friction, thereby achieving high-precision and high-stability measurements.

[0137] It should be noted that the application areas of this device include, but are not limited to:

[0138] Precision optics and optical assembly: mirror collimation and autocollimation correction of telescopes / optical stages, fine-tuning and position verification of optical component assembly;

[0139] Laboratory precision metrology and calibration: Demonstration instruments and metrology institutions for physics / optics experimental teaching in higher education institutions perform micro-motion calibration and verification of angle stages, rotary stages, guide rail gaps, etc.

[0140] Industrial quality control and online inspection: micro-tilt detection of machine tool spindles / guideways, assembly error detection of precision machined parts, and micro-displacement monitoring in lithography or semiconductor equipment;

[0141] Structural and equipment health monitoring: long-term micro-tilt monitoring and periodic diagnosis of bridges, towers or precision structures (as a high-sensitivity tilt sensing unit).

[0142] Research and development platform: nanometer / micrometer level displacement measurement, dynamic characterization of MEMS devices, micro-deformation experiments and vibration response testing of materials.

[0143] Potential and scalable applications (new scenarios realized through system integration and engineering extensions) include:

[0144] Closed-loop control and active stabilization: Integrating the measurement module output into the real-time control loop for active attitude / position stabilization of the test bench or instrument (such as automatic stabilization of astronomical telescopes and frequency stabilization of laser optical paths).

[0145] Industry 4.0 smart sensing node: After being lightweighted and modularized, it serves as a high-precision displacement / angle sensor embedded in the production line, supporting remote data reporting and online statistical analysis;

[0146] Portable / Field Rapid Calibration Instrument: Enables rapid micro-tilt verification and positioning of large machinery, assembly lines, or structures on-site;

[0147] Productization of teaching and popular science: Using the dynamic visualization of interference fringes as a teaching demonstrator to popularize the principles of interferometry and apply them to interdisciplinary experimental courses.

[0148] At the technical implementation level, this invention is applicable to controlled laboratory environments (in conjunction with inertial bases, constant temperature and humidity chambers, vibration damping tables, cleanrooms, etc. to achieve the highest sensitivity), and can also be extended to industrial sites and general teaching environments through engineering modifications (windproof and dustproof shell, lightweight camera and active magnetic control for vibration resistance).

[0149] Assembly sequence:

[0150] After the base is in place and leveled, the fixing gear rings 134 of each planetary gear acceleration assembly 13 are fixed.

[0151] Assemble the gear set and preload the bearings;

[0152] Install the helical cam 31, rolling bearing 21 and linear guide 2 and level them;

[0153] Install the upper magnetic coupling magnet 62 and the lower magnetic coupling magnet 63 and initially set the magnetic distance;

[0154] Install electromagnetic unit 6121 and displacement sensor 6122;

[0155] Installation of the Michelson interferometer assembly and coarse adjustment of the interferometric optical path;

[0156] Camera and processor installation;

[0157] Software power-on calibration.

[0158] System calibration steps:

[0159] Mechanical amplification factor calibration: Record the changes and displacements of the corresponding interference fringes at a known input angle, calculate the mechanical amplification factor and generate a correction table;

[0160] Optical reference arm length calibration: Verify the relationship between displacement and camera scale conversion using known displacement values;

[0161] Camera pixel scale calibration;

[0162] After the deep learning model dataset is trained and calibrated, the system can achieve absolute angle output and guarantee repeatability.

[0163] Algorithm calibration: Run the counting algorithm under multiple operating conditions and compare it with manual or known references, and adjust the threshold and filtering parameters to ensure that the false positive rate is lower than the predetermined level.

[0164] System workflow:

[0165] Start the device and adjust the positions of M1 and M2 until a clear interference pattern appears on the interference screen. Align the camera with the reticle, ensuring the interference rings are centered. Angle measurement: Begin recording images; automatically analyze changes in the number of rings after completion.

[0166] Data Processing: The image processing system identifies bright / dark spots using the YOLOv8 model. It determines the ring number change based on the center spot type and area variation. Substituting these values ​​into the angle calculation model, it calculates minute angle changes. The angle change value of the measured object is output in real time. Example 2

[0167] A method for dynamic measurement of microradian angles

[0168] Reference Figure 7 As shown, Figure 7 A flowchart illustrating a microradian-level dynamic angle measurement method provided in one embodiment of this specification may include at least the following steps:

[0169] Step 102: Obtain the transmission ratio between the input and output shafts of the transmission gear set, the angle-displacement conversion coefficient of the angle-displacement conversion component, the incident light wavelength of the Michelson interferometer component, and the time-series interference image set;

[0170] Step 104: Obtain the time-series data of the angle change of the object under test based on the transmission ratio, angle-displacement conversion coefficient, incident light wavelength and time-series interferometric image set.

[0171] In one embodiment of this specification, step 104 acquires time-series data of the angle change of the object under test based on the transmission ratio, angle-to-displacement conversion coefficient, incident light wavelength, and time-series interferometric image set, including:

[0172] The center spot type and center spot area of ​​each interference image are obtained based on the temporal interferometric image set;

[0173] The change in the number of interference fringes is determined based on the type and area of ​​the center spot corresponding to each of the adjacent interference images.

[0174] The time-series data of the angle change of the object under test are obtained based on the changes in transmission ratio, angle-displacement conversion coefficient, incident light wavelength, and the number of interference fringes corresponding to each pair of adjacent interference images.

[0175] For explanation, the transmission ratio is k1 (e.g., 1 / 120), the angle-to-displacement conversion coefficient is k2 (e.g., mm / rad), and the incident light wavelength is λ=632.8nm. Based on the change in the number of interference fringes corresponding to each pair of adjacent interference images, Δδ is calculated using the relationship between the displacement Δδ of the moving mirror M2 and the number of interference fringes Δδ=N×(λ / 2). Then, the angle change value θ of the measured object corresponding to each adjacent interference image is calculated using the formula θ=(Δδ / k2) / k1, thus obtaining the angle change time series data.

[0176] In one embodiment of this specification, determining the change in the number of interference fringes based on the center spot type and center spot area of ​​each adjacent interference image includes:

[0177] When the center spot type of adjacent interference images changes from bright spot to dark spot, and the absolute value of the change in the area of ​​the corresponding center spot in each adjacent interference image is greater than a preset threshold;

[0178] If the change in the area of ​​the central spot is negative, the number of interference fringes increases by one;

[0179] If the change in the area of ​​the central spot is positive, the number of interference fringes remains unchanged;

[0180] When the center spot type of adjacent interference images changes from dark spot to bright spot, and the absolute value of the change in the area of ​​the corresponding center spot in each adjacent interference image is greater than a preset threshold;

[0181] If the change in the area of ​​the central spot is positive, the number of interference fringes decreases by one.

[0182] If the change in the area of ​​the central spot is negative, the number of interference fringes remains unchanged.

[0183] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0184] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the embodiments of the dynamic angle measurement method are basically similar to the embodiments of the dynamic angle measurement device, so the description is relatively simple; relevant parts can be referred to the descriptions of the dynamic angle measurement device embodiments.

[0185] Example 3

[0186] An electronic device

[0187] like Figure 8 As shown, the electronic device 7 may include at least one processor 701, at least one network interface 704, a user interface 703, a memory 705, and at least one communication bus 702.

[0188] The communication bus 702 can be used to realize the connection and communication of the above components.

[0189] The user interface 703 may include buttons, and the optional user interface may also include a standard wired interface or a wireless interface.

[0190] The network interface 704 may include, but is not limited to, Bluetooth modules, NFC modules, Wi-Fi modules, etc.

[0191] The processor 701 may include one or more processing cores. The processor 701 connects to various parts within the electronic device 7 using various interfaces and lines. It executes various functions and processes data of the electronic device 7 by running or executing instructions, programs, code sets, or instruction sets stored in the memory 705, and by calling data stored in the memory 705. Optionally, the processor 701 may be implemented using at least one hardware form selected from DSP, FPGA, and PLC. The processor 701 may integrate one or more of the following: CPU, GPU, and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the content required for display; and the modem handles wireless communication. It is understood that the modem may also not be integrated into the processor 701 and may be implemented as a separate chip.

[0192] The memory 705 may include RAM or ROM. Optionally, the memory 705 may include a non-transitory computer-readable medium. The memory 705 may be used to store instructions, programs, code, code sets, or instruction sets. The memory 705 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the above-described method embodiments, etc.; the data storage area may store data involved in the above-described method embodiments, etc. Optionally, the memory 705 may also be at least one storage device located remotely from the aforementioned processor 701. As a computer storage medium, the memory 705 may include an operating system, a network communication module, a user interface module, and an angle dynamic measurement method application program. The processor 701 may be used to call the angle dynamic measurement method application program stored in the memory 705 and execute the steps of the angle dynamic measurement method mentioned in the foregoing embodiments.

[0193] This specification also provides a computer-readable storage medium storing instructions that, when executed on a computer or processor, cause the computer or processor to perform one or more steps in the above-described embodiments of the dynamic angle measurement method. If the constituent modules of the above-described electronic device are implemented as software functional units and sold or used as independent products, they can be stored in the computer-readable storage medium.

[0194] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this specification are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in or transmitted through a computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., Digital Versatile Discs (DVDs)), or semiconductor media (e.g., Solid State Disks (SSDs)).

[0195] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks. Unless otherwise specified, the technical features of this embodiment and its implementation can be combined arbitrarily.

[0196] The embodiments described above are merely preferred embodiments of this specification and are not intended to limit the scope of this specification. Any modifications and improvements made by those skilled in the art to the technical solutions of this specification without departing from the spirit of this specification should fall within the protection scope defined by the claims of this specification.

Claims

1. A micro-radian-level dynamic angle measuring device, characterized in that, Includes a mechanical angle amplification unit, an angle-displacement conversion unit, an interference image acquisition unit, and an interference image processing unit (5); The mechanical angle magnification unit includes a transmission gear set (1), the transmission ratio between the input shaft (11) and the output shaft (12) of the transmission gear set (1) is less than 1, the input shaft (11) is used to connect to the object under test to synchronously acquire the angle change of the object under test, and the output shaft (12) synchronously magnifies the angle change; The angle-displacement conversion unit includes a linear guide rail (2) and an angle-displacement conversion component (3). The angle-displacement conversion component (3) is used to convert the angle change amplified by the transmission gear set (1) into a linear displacement change. The linear guide rail (2) moves with the linear displacement change. The interferometric image acquisition unit includes a Michelson interferometer component that converts displacement changes into optical path difference changes and a pattern acquisition device. The Michelson interferometer component includes a moving mirror M2 (4) disposed on the linear guide rail (2). The pattern acquisition device acquires interferometric images in real time to obtain a time-series interferometric image set characterizing the optical path difference changes. The interference image processing unit (5) acquires the time-series data of the angle change of the object under test based on the time-series interference image set.

2. The micro-radian-level dynamic angle measuring device according to claim 1, characterized in that, The interference image processing unit (5) includes a center spot detection module (51), a fringe change determination module (52), and a data processing module (53). The center spot detection module (51) obtains the center spot type and center spot area of ​​each interference image in the temporal interference image set based on a deep learning model; The fringe change determination module (52) determines the change in the number of interference fringes based on the center spot type and center spot area of ​​each of the adjacent interference images. The data processing module (53) obtains the time-series data of the angle change of the tested object based on the change in the number of interference fringes corresponding to each pair of adjacent interference images.

3. The micro-radian-level dynamic angle measuring device according to claim 2, characterized in that, The central spot types include light spots and dark spots; The fringe change determination module (52) increments the number of interference fringes by one if the change in the center spot type of adjacent interference images changes from bright to dark, and the absolute value of the change in the center spot area of ​​each adjacent interference image is greater than a preset threshold; if the change in the center spot area is negative, the number of interference fringes remains unchanged if the change in the center spot area is positive. When the center spot type of adjacent interference images changes from dark spot to bright spot, and the absolute value of the change in the center spot area of ​​each adjacent interference image is greater than a preset threshold, if the change in the center spot area is positive, the number of interference fringes decreases by one; if the change in the center spot area is negative, the number of interference fringes remains unchanged.

4. The micro-radian-level dynamic angle measuring device according to claim 1, characterized in that, The transmission gear set (1) includes multiple coaxially arranged planetary gear acceleration assemblies (13), wherein the planet carrier (131) of the primary planetary gear acceleration assembly (13) is the input shaft (11), and the sun gear (132) of the final planetary gear acceleration assembly (13) is the output shaft (12).

5. The micro-radian-level dynamic angle measuring device according to claim 4, characterized in that, The angle-displacement conversion assembly (3) includes a spiral cam (31) coaxially arranged with the sun gear (132) of the final stage planetary gear acceleration assembly (13). The linear guide (2) is provided with a rolling bearing (21) whose axial direction is perpendicular to the length direction of the linear guide (2) and parallel to the output shaft (12) of the transmission gear set (1), and a reset traction member (22) that applies a driving force from the rolling bearing (21) to the helical cam (31), so that the side wall of the rolling bearing (21) abuts against the side wall of the helical cam (31).

6. The micro-radian-level dynamic angle measuring device according to claim 1, characterized in that, A magnetic coupling transmission mechanism (6) is provided between the moving mirror M2 (4) and the linear guide rail (2). The magnetic coupling transmission mechanism (6) includes an anti-gravity suspension component (61), an upper magnet (62), and a lower magnet (63) disposed on the top of the linear guide rail (2) and having the opposite polarity to the upper magnet (62). The upper magnet (62) and the lower magnet (63) are disposed opposite to each other. The antigravity levitation assembly (61) includes a magnetic track (611) fixedly positioned above the linear guide rail (2) and aligned with the length direction of the linear guide rail (2), and a magnetic frame (612) surrounding the magnetic track (611) and movable along the length direction of the magnetic track (611). The upper end face of the magnetic frame (612) is connected to the moving mirror M2 (4), and the lower end face is connected to the upper magnet (62). The magnetic track (611) provides the magnetic frame (612) with antigravity and a horizontal balancing force perpendicular to the length direction of the magnetic track (611), so that the magnetic frame (612) is in a stable levitation state and the upper magnet (62) and the lower magnet (63) maintain a fixed gap.

7. The micro-radian-level dynamic angle measuring device according to claim 6, characterized in that, The magnetic track (611) has two symmetrically arranged permanent magnet arrays (6111) on its upper end face along its own length direction. The magnetic frame (612) has multiple electromagnetic units (6121) corresponding to the two permanent magnet arrays (6111) on its inner top side, and multiple displacement sensors (6122) are arranged in an alternating pattern on its inner bottom side to obtain the attitude information of the magnetic frame (612). The antigravity levitation assembly (61) also includes an attitude controller that controls the magnitude of the electromagnetic force generated by each of the electromagnetic units (6121) based on attitude information.

8. A dynamic angle measurement method based on the micro-radian-level dynamic angle measuring device according to any one of claims 1-7, characterized in that, Includes the following steps: Acquire the transmission ratio between the input and output shafts of the transmission gear set, the angle-to-displacement conversion coefficient of the angle-to-displacement conversion component, the incident light wavelength of the Michelson interferometer component, and the time-series interference image set; The time-series data of the angle change of the object under test are obtained based on the transmission ratio, angle-displacement conversion coefficient, incident light wavelength and time-series interferometric image set.

9. The angle dynamic measurement method according to claim 8, characterized in that, The method of acquiring time-series data on the angle change of the measured object based on the transmission ratio, angle-to-displacement conversion coefficient, incident light wavelength, and time-series interferometric image set includes: The center spot type and center spot area of ​​each interference image are obtained based on the temporal interferometric image set; The change in the number of interference fringes is determined based on the type and area of ​​the center spot corresponding to each of the adjacent interference images. The time-series data of the angle change of the object under test are obtained based on the changes in transmission ratio, angle-displacement conversion coefficient, incident light wavelength, and the number of interference fringes corresponding to each pair of adjacent interference images.

10. The angle dynamic measurement method according to claim 9, characterized in that, The method of determining the change in the number of interference fringes based on the center spot type and center spot area of ​​each adjacent interference image includes: When the center spot type of adjacent interference images changes from bright spot to dark spot, and the absolute value of the change in the area of ​​the corresponding center spot in each adjacent interference image is greater than a preset threshold; If the change in the area of ​​the central spot is negative, the number of interference fringes increases by one; If the change in the area of ​​the central spot is positive, the number of interference fringes remains unchanged; When the center spot type of adjacent interference images changes from dark spot to bright spot, and the absolute value of the change in the area of ​​the corresponding center spot in each adjacent interference image is greater than a preset threshold; If the change in the area of ​​the central spot is positive, the number of interference fringes decreases by one. If the change in the area of ​​the central spot is negative, the number of interference fringes remains unchanged.

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