Optical inclination angle measuring device

Abstract

The invention discloses an optical inclination angle measuring device, and relates to the technical field of precision measurement and optical sensing. The device comprises a rotating shaft seat and a reflection assembly, and is characterized in that a swing mechanism is rotatably connected above the rotating shaft seat, and the swing mechanism always points to the vertical direction under the action of gravity; a laser emitting module is fixedly installed on the swing mechanism, and the incident light of the laser emitting module is downward and forms an angle alpha with the vertical direction. According to the invention, the swing mechanism is adopted to carry the laser and is combined with the specially designed reflection assembly, so that the tiny dip angle change is creatively converted into the long-distance advancing back-and-forth reflection of the light beam in the reflection assembly, and the synergistic effect of the optical lever and the multiple reflection light path amplification enables the tiny angular displacement to be greatly amplified; therefore, the light can be clearly captured by the rear-end light-sensitive element, and the physical precision limit faced by the traditional MEMS sensor is overcome.

Description

Technical Field

[0001] This invention relates to the field of precision measurement and optical sensing technology, specifically to an optical tilt angle measuring device. Background Technology

[0002] Tilt measurement, as a core technology for attitude sensing and deformation monitoring, plays a crucial role in fields such as large-scale precision equipment manufacturing, bridge and tunnel structural health monitoring, high-rise building settlement observation, and spacecraft attitude control. Its measurement accuracy directly determines the stability margin of the system's closed-loop control and the sensitivity of safety warnings. In recent years, with the accelerated pace of self-reliance in the high-end equipment manufacturing industry, there has been an urgent demand for high-precision tilt sensors with "sub-arcsecond resolution, miniaturized integration, and long-term stability."

[0003] Microelectromechanical systems (MEMS)-based tilt sensors, thanks to their miniaturization, low cost, and low power consumption advantages brought by silicon-based mass production, have been widely used in consumer electronics and low-to-mid-range industrial fields. However, limited by the quality of the silicon wafers, the temperature characteristics of the damping layer, and the inherent noise of the readout circuit, the core performance indicators of MEMS tilt sensors have insurmountable limitations: their zero-bias repeatability is typically only 0.01° (approximately 36 arcseconds), the temperature drift coefficient is approximately ±0.005° / ℃, and the cumulative drift can reach over 0.02° under long-term operation (e.g., 1000 hours). For ultra-precision applications such as telescope gravity deformation monitoring, high-speed railway track slab settlement measurement (requiring accuracy better than 0.3 arcseconds), or high-end CNC machine tool geometric error compensation (requiring accuracy down to 0.1 arcseconds), the existing accuracy reserves of MEMS sensors are almost zero. Although the industry has attempted to improve the device through hardware and software enhancements such as "multi-sensor array + temperature compensation + Kalman filtering", it is impossible to fundamentally eliminate the noise and mechanical quality factor (Q value) limitations determined by its physical nature. Therefore, this invention proposes an optical tilt angle measurement device. Summary of the Invention

[0004] The purpose of this invention is to provide an optical tilt angle measuring device to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an optical tilt angle measuring device, comprising a rotating shaft seat and a reflective assembly, wherein a swing mechanism is rotatably connected above the rotating shaft seat, and the swing mechanism always points in the vertical direction under the action of gravity; A laser emitting module is fixedly installed on the swing mechanism, and the incident light from the laser emitting module forms an angle α with the vertical direction downwards. The reflective component is disposed in the incident light path of the laser emitting module, and is used to receive and reflect the laser beam multiple times to extend the optical path and form the outgoing light. Among them, an attenuation filter and a photosensitive element are arranged sequentially in the optical path of the emitted light.

[0006] Furthermore, it also includes a housing, with the pivot seat and reflector assembly both fixed inside the housing.

[0007] Furthermore, the number of the rotating shaft seats is two, the two rotating shaft seats are arranged in a straight line, and there is a gap between the two rotating shaft seats; Both pivot seats have arc grooves on their tops.

[0008] Furthermore, the swing mechanism includes a crossbeam rotatably connected in the arc groove of the rotating shaft seat. A triangular block is fixedly installed at the bottom of the crossbeam. The bottom end of the triangular block is rounded. The number of triangular blocks corresponds one-to-one with the arc groove, and the triangular block and the arc groove form a rotating pair to realize the rotational connection between the rotating seat and the crossbeam.

[0009] Furthermore, a swing arm is fixedly installed at the center of the crossbeam, a counterweight is fixedly installed at the bottom end of the swing arm, and limit rods are provided on both sides of the swing arm, with the limit rods fixedly installed inside the housing.

[0010] Furthermore, the reflective component includes an upper reflective surface, a lower reflective surface, and an oblique reflective surface. The lower reflective surface and the upper reflective surface are arranged in parallel and opposite to each other. The oblique reflective surface is located at the right end of the lower reflective surface, and the oblique reflective surface has an angle β with the horizontal direction, so that the emitted light is deviated from the rightmost end of the upper reflective surface by a certain distance.

[0011] Furthermore, the laser emitting module is configured as a laser, and the incident light from the laser emitting module is projected onto the lower reflective surface of the reflective component. After multiple reflections, the incident light forms an outgoing light on the oblique reflective surface.

[0012] Furthermore, the photosensitive element is configured as a CCD line scan camera or a CMOS line scan camera, and the photosensitive element is positioned horizontally on the right side of the upper reflective surface, located at the point where the emitted light is projected.

[0013] Furthermore, the hammer is made of copper or steel.

[0014] Furthermore, both angles α and β are set to 1°-3°.

[0015] The present invention has at least the following beneficial effects: 1. This invention creatively transforms minute tilt angle changes into long-distance back-and-forth reflections of the light beam within the reflective component by employing a swing mechanism to carry a laser. This synergistic effect of optical lever and multiple reflections amplifies the optical path, greatly amplifying extremely small angular displacements so that they can be clearly captured by the photosensitive element at the back end. This overcomes the physical accuracy limits faced by traditional MEMS sensors. Furthermore, by performing multiple reflections within the reflective component, the effective optical detection path is greatly extended within a limited housing space, thus achieving the effect of "small size, long optical path, and high amplification." This compact design makes the device easier to integrate into high-end equipment with limited space, broadening its application scenarios.

[0016] 2. The counterweight design in the swing mechanism of this invention endows the entire system with a huge moment of inertia, giving it a strong inertial suppression effect against high-frequency micro-vibrations from the outside world and effectively filtering out environmental interference. Simultaneously, the support system formed by the triangular block and the rotating shaft seat has extremely low friction, ensuring the sensitivity of the swing response and the consistency of zero return. The reflective component and the rotating shaft seat are fixed together in the same housing, establishing a unified and stable measurement benchmark, effectively avoiding errors caused by benchmark drift, and ensuring the reliability and repeatability of long-term measurements.

[0017] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a three-dimensional schematic diagram of the swing mechanism of the present invention.

[0019] Figure Labels 1. Housing; 2. Rotary shaft seat; 3. Laser emitting module; 4. Circular groove; 5. Crossbeam; 6. Triangular block; 7. Swing rod; 8. Counterweight; 9. Limiting rod; 10. Upper reflective surface; 11. Lower reflective surface; 12. Oblique reflective surface; 13. Attenuation filter; 14. Photosensitive element. Detailed Implementation

[0020] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0021] Please see Figures 1-2The present invention provides a technical solution: an optical tilt angle measuring device, including a rotating shaft seat 2 and a reflective component, wherein a swing mechanism is rotatably connected above the rotating shaft seat 2, and the swing mechanism always points in the vertical direction under the action of gravity; A laser emitting module 3 is fixedly installed on the swing mechanism, and the incident light of the laser emitting module 3 forms an angle α with the vertical direction downward. The reflective component is set in the incident light path of the laser emitting module 3 to receive and reflect the laser beam multiple times to extend the optical path and form the outgoing light. Among them, an attenuation filter 13 and a photosensitive element 14 are arranged sequentially in the optical path of the emitted light to reduce the intensity of the laser light and protect the photosensitive element 14.

[0022] The technical solution of this embodiment also includes a housing 1, with the pivot seat 2 and the reflective component all fixed inside the housing 1. The housing 1 forms a protective space, providing a crucial barrier for the internal precision components.

[0023] Regarding the technical solution of this embodiment, there are two pivot seats 2. The two pivot seats 2 are arranged in a straight line and fixed on the side walls on both sides of the housing 1, and there is a gap between the two pivot seats 2. The top of each of the two pivot seats 2 is provided with an arc groove 4. The swing mechanism has a certain weight and length. Single-point support is difficult to resist torsional torque, which can easily cause the crossbeam 5 to tilt or get stuck. Double-point support distributes the load evenly on the two support points, which greatly enhances the rigidity and stability of the structure and ensures that the swing mechanism can only swing freely in the preset plane under the action of gravity. This is the premise of high-precision angle reference.

[0024] Regarding the technical solution of this embodiment, the swing mechanism includes a crossbeam 5 rotatably connected in the arc groove 4 of the rotating shaft seat 2. A triangular block 6 is fixedly installed at the bottom of the crossbeam 5. The bottom end of the triangular block 6 is rounded. The number of triangular blocks 6 corresponds one-to-one with the arc groove 4, and the triangular block 6 and the arc groove 4 form a rotating pair to realize the rotational connection between the rotating seat and the crossbeam 5. The arc groove 4 plays a natural positioning role for the triangular corner. No matter how the swing mechanism swings, its rotation center is always constrained on the common tangent line of the contact point between the corner and the arc groove 4. This design ensures the high repeatability and stability of the rotation center and avoids the measurement error introduced by the fulcrum drift. Furthermore, the lower edge of the triangular block 6 engages with the arc groove 4 on the top of the rotating shaft seat 2, forming a classic "knife-edge support" principle. The contact form is line contact, which significantly reduces both static and dynamic friction torque compared to surface contact (such as sliding bearings). Lower friction means that the swing mechanism is more sensitive to small tilt angle changes, can respond quickly and accurately, directly improving the resolution and accuracy of the measurement. Therefore, the swing mechanism and the rotating shaft seat 2 together realize a precision rotary support system with low friction, high rigidity, high repeatability and anti-interference, which ensures that the swing mechanism, as the angle reference, can work accurately, stably and sensitively.

[0025] In this embodiment, a swing arm 7 is fixedly installed at the center of the crossbeam 5, and a counterweight 8 is fixedly installed at the bottom of the swing arm 7. Limiting rods 9 are provided on both sides of the swing arm 7. The limiting rods 9 are fixedly installed inside the housing 1. When the device is subjected to a strong impact (such as an accidental collision during transportation or installation) or a large and rapid tilt, the swing amplitude of the swing arm 7 may increase sharply. Without the limiting rods 9, the huge inertial force may cause permanent damage (such as bumps or deformation) to the fragile triangular block 6 edges and the arc groove 4 of the rotating shaft seat 2, or even lead to structural failure. By means of physical interference, the swing angle of the swing arm 7 is limited within a safe mechanical range to limit the swing amplitude of the swing arm 7 and avoid damage. Furthermore, if the swing amplitude of the swing arm 7 is too large, it will cause the light spot to move out of the effective detection area of ​​the photosensitive element 14, which will lead to measurement failure.

[0026] Regarding the technical solution of this embodiment, the reflective component includes an upper reflective surface 10, a lower reflective surface 11, and an oblique reflective surface 12. The lower reflective surface 11 and the upper reflective surface 10 are arranged in parallel and opposite to each other. The oblique reflective surface 12 is located at the right end of the lower reflective surface 11, and the oblique reflective surface 12 has an angle β with the horizontal direction, so that the outgoing light is deviated from the rightmost end of the upper reflective surface 10 by a certain distance. The incident light is projected onto the lower reflective surface 11 of the reflective component. After multiple reflections, the incident light forms an outgoing light on the oblique reflective surface 12. In a limited cavity with the upper and lower reflective surfaces 11 arranged in parallel, if the light returns along the original path, the photosensitive element 14 must be directly facing the end of the upper reflective surface 10, which causes the optical path and mechanical structure to be stacked in the vertical direction, doubling the thickness. Therefore, the outgoing light is deflected laterally by the oblique reflective surface 12, forming an independent mounting position on the horizontal side of the upper reflective surface 10, so as to avoid blocking part of the optical path or touching the precision reflective surface during installation or debugging, thereby introducing errors or causing damage. Furthermore, if the exit point is close to the end of the upper reflective surface 10, specular scattered light and diffuse reflection can easily enter the pixel area of ​​the photosensitive element 14, forming background noise. The oblique reflective surface 12 physically shifts the exit point, and combined with the light-absorbing treatment of the housing 1, stray light needs to undergo multiple unexpected reflections before reaching the detector, resulting in significant energy attenuation. This ensures that the edge of the effective light spot is clear and supports sub-arcsecond-level weak signal resolution capability. Meanwhile, traditional multiple reflection systems require the incident point, reflecting surface, and detector to be strictly coplanar, which makes calibration difficult. The oblique reflecting surface 12 separates the final outgoing light path from the main reflection area, and the installation position of the photosensitive element 14 is no longer restricted by the geometric constraints of the reflecting surface. It can be flexibly adjusted within the deflection range designed by the β angle, which facilitates assembly calibration and subsequent maintenance, and reduces the cost of precision assembly and adjustment.

[0027] In this embodiment, the laser emitting module 3 is configured as a laser, and the photosensitive element 14 is configured as a CCD linear array camera or a CMOS linear array camera. The photosensitive element 14 is positioned horizontally on the right side of the upper reflecting surface 10, at the point where the emitted light is projected. The CCD or CMOS linear array camera has a continuous pixel array structure, which can directly capture the one-dimensional energy distribution curve of the light spot. By using a centroid algorithm, it overcomes the physical size limitation of a single pixel, achieving precise interpolation positioning of the center position of the light spot. Compared with discrete photodiodes or PSD devices, the linear array camera has better pixel consistency and can ensure full-range measurement linearity without complex nonlinear correction.

[0028] In this embodiment, the weight 8 is made of copper or steel. Copper or steel is chosen because both are crystalline materials with high rigidity and strength, and are not prone to creep or plastic deformation. This means that under long-term gravity loads, the geometry and dimensions of the weight 8 can remain highly stable, and the center of mass of the swing mechanism will not change due to its own deformation, thus ensuring the long-term zero-point stability of the angle reference.

[0029] In this embodiment, both angles α and β are set to 1°-3°. When the housing 1 is not tilted, the incident laser beam has a small angle α with the pendulum 7. The upper reflecting surface 10 and the lower reflecting surface 11 of the reflecting assembly are parallel and opposite to each other, with a distance of [missing information]. h After the incident light enters the reflective component, it undergoes multiple reflections between the upper reflective surface 10 and the lower reflective surface 11, increasing the optical path. In one reflection, the light travels a certain distance in the horizontal direction. l for: At the final point of the emitted light beam, an oblique reflector 12 is positioned to the right of the lower reflector 11. This oblique reflector 12 forms an angle β with the lower reflector 11. This angle causes the emitted light beam to deviate outward from the swing arm 7, resulting in the laser projection point being to the right of the upper reflector 10. wLocation: w The distance facilitates the installation of the photosensitive element 14, which is located at the laser projection point, with an attenuation filter 13 at its front end.

[0030] Overall, the laser passes through the reflective component 3. n After the second reflection, the distance traveled in the horizontal direction y for: Differentiating the above equation yields the sensitivity of the device. k for: The following is a set of parameters set in the example: h =60mm, α =2°, β =2°, number of reflections n =20, the calculated lateral dimension y =90.1mm; sensitivity k=2404mm / rad, if the pixel size of the photosensitive element is 10μm, then the minimum detection angle is: Achieving sub-second high-precision tilt angle detection, among which w =10.5mm, which also provides enough space for the photosensitive element.

[0031] In summary, this invention creatively transforms minute tilt angle changes into long-distance back-and-forth reflections of the light beam within the reflective component by employing a swing mechanism to carry a laser. This synergistic effect of optical lever and multiple reflections amplifies the optical path, greatly amplifying extremely small angular displacements so that they can be clearly captured by the photosensitive element 14 at the rear end. This fundamentally overcomes the physical accuracy limits faced by traditional MEMS sensors. Furthermore, by performing multiple reflections within the reflective component, the effective optical detection path is greatly extended within the limited space of the housing 1, thus achieving the effect of "small size, long optical path, and high amplification." This compact design makes the device easier to integrate into high-end equipment with limited space, broadening its application scenarios.

[0032] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0033] For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances. When an element is referred to as being "assembled on," "mounted on," "fixed to," or "set on" another element, it may be directly on the other element or there may be an intermediate element present. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible embodiments.

[0034] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0035] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. An optical tilt measuring device, comprising a rotating shaft seat (2) and a reflective assembly, characterized in that, A swing mechanism is rotatably connected above the rotating shaft seat (2), and the swing mechanism always points in the vertical direction under the action of gravity. A laser emitting module (3) is fixedly installed on the swing mechanism, and the incident light of the laser emitting module (3) forms an angle α with the vertical direction downward. The reflective component is disposed on the incident light path of the laser emitting module (3) to receive and reflect the laser beam multiple times to extend the optical path and form the outgoing light. Among them, an attenuation filter (13) and a photosensitive element (14) are arranged sequentially in the optical path of the emitted light.

2. The optical tilt measuring device according to claim 1, characterized in that: It also includes a housing (1), a rotating shaft seat (2), and a reflective assembly, all of which are fixed inside the housing (1).

3. The optical tilt measuring device according to claim 2, characterized in that: The number of the rotating shaft seats (2) is two, the two rotating shaft seats (2) are arranged in a straight line, and there is a gap between the two rotating shaft seats (2); Both of the two pivot seats (2) have arc grooves (4) on their tops.

4. The optical tilt measuring device according to claim 3, characterized in that: The swing mechanism includes a crossbeam (5) rotatably connected in the arc groove (4) of the rotating shaft seat (2). A triangular block (6) is fixedly installed at the bottom of the crossbeam (5). The bottom end of the triangular block (6) is rounded. The number of triangular blocks (6) corresponds one-to-one with the arc groove (4). The triangular block (6) and the arc groove (4) form a rotating pair to realize the rotational connection between the rotating seat and the crossbeam (5).

5. The optical tilt measuring device according to claim 4, characterized in that: A swing arm (7) is fixedly installed at the center of the crossbeam (5), a weight (8) is fixedly installed at the bottom of the swing arm (7), and limit rods (9) are provided on both sides of the swing arm (7), with the limit rods (9) fixedly installed inside the shell (1).

6. The optical tilt measuring device according to claim 4, characterized in that: The reflective component includes an upper reflective surface (10), a lower reflective surface (11), and an oblique reflective surface (12). The lower reflective surface (11) and the upper reflective surface (10) are arranged in parallel and opposite to each other. The oblique reflective surface (12) is located at the right end of the lower reflective surface (11), and the oblique reflective surface (12) has an angle β with the horizontal direction, so that the emitted light is deviated from the rightmost end of the upper reflective surface (10) by a certain distance.

7. The optical tilt measuring device according to claim 6, characterized in that: The laser emitting module (3) is configured as a laser, and the incident light of the laser emitting module (3) is projected onto the lower reflective surface (11) of the reflective component. After multiple reflections, the incident light forms an outgoing light on the oblique reflective surface (12).

8. The optical tilt measuring device according to claim 7, characterized in that: The photosensitive element (14) is configured as a CCD line array camera or a CMOS line array camera. The photosensitive element (14) is positioned horizontally on the right side of the upper reflective surface (10) and is located at the point where the emitted light is projected.

9. An optical tilt measuring device according to claim 5, characterized in that: The hammer (8) is made of copper or steel.

10. An optical tilt measuring device according to claim 6, characterized in that: Both angles α and β are set to 1°-3°.

Images