High-precision small-angle generating device and method based on optical path folding amplification

Abstract

The application relates to the technical field of metrology and precision measurement, and more particularly to a high-precision small-angle generating device and method based on light path folding amplification. The device comprises a laser, a base, a sinusoidal arm, a hinge, a detector for detecting the position of a light spot, an exciter for generating a micro displacement, and a mirror; one end of the sinusoidal arm is rotationally connected to one end of the base through the hinge, the exciter is installed at the other end of the base, the driving end of the exciter is in contact with the other end of the sinusoidal arm, the mirror is installed on the sinusoidal arm, the exciter drives the sinusoidal arm to rotate around the rotation center of the hinge, thereby driving the mirror to change the angle; the two opposite side walls of the base and the sinusoidal arm are each provided with a planar light reflection module, a light inlet through hole is formed at the end of the base close to the hinge, the detector is installed on the base or the first sinusoidal arm; and the laser is located at the light inlet through hole. The application reduces the complexity of the device, is simple to operate, and improves the stability of measurement.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metrology and precision measurement, and more particularly to a high-precision small-angle generating device and method based on optical path folding amplification. BACKGROUND

[0002] A small-angle generator is a device used to generate precise small angles and is widely used in metrology, optical measurement, aerospace, precision machinery and other fields. Its main function is to provide precise angle reference for various angle measuring instruments to ensure the accuracy and consistency of measurement. There are two mechanisms for small-angle generators, one is to subdivide a full circle, and the other is to use the sine theorem to generate angles according to the definition of m / m in the International System of Units.

[0003] The I2D-SAG small-angle calibration device developed by the Finnish National Metrology Institute uses three heterodyne interferometers to measure the angle direction of the reference plane in space. Before measurement, the reference plane is adjusted to be perpendicular to the light beam of the interferometer, and then the rotation of the reference plane in the horizontal and vertical directions is performed by using an independent support frame with air bearings and electric angular motion. It can achieve calibration within ±1000" with a standard uncertainty of better than 0.01" ≈ 50 nrad, and it can achieve two-dimensional angle calibration with high precision, but the optical path and device are complex. The existing Chinese patent number discloses a small-angle generator, which includes a precision cylindrical shaft, a precision electronic digital display indicator, a mechanical lifting device, a table plate, a fastening device, etc. The mechanical lifting device is used to adjust the rotation of the sine arm around the shaft to generate small angles. This small-angle generator device is complex, requires high processing precision, and the wear of the lifting device, thermal expansion and contraction of parts caused by environmental temperature changes, etc. will affect the stability of the measurement results.

[0004] Traditional small-angle generators often have difficulty achieving high-precision angle generation due to complex structure and manufacturing process limitations. Existing high-precision angle generators usually have complex optical paths or devices, requiring complex operation and calibration processes, increasing the time cost and operation difficulty for users. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art small-angle generator, such as complex structure and difficult measurement and calibration, and to provide a high-precision small-angle generating device and method based on optical path folding amplification, which reduces the complexity of the device, is easy to operate, and improves the stability of the measurement.

[0006] To solve the above technical problems, the technical solution adopted by the present application is:

[0007] The application provides a high-precision small-angle generating device based on optical path folding amplification, which comprises a laser, a base, a sinusoidal arm, a hinge, a probe for detecting a light spot position, an exciter for generating a micro displacement, and a mirror; one end of the sinusoidal arm is rotationally connected to one end of the base through the hinge, the exciter is installed at the other end of the base, a driving end of the exciter is in contact with the other end of the sinusoidal arm, the mirror is installed on the sinusoidal arm, the exciter drives the sinusoidal arm to rotate around the rotation center of the hinge, so that the mirror is driven to change the angle, and plane reflection modules are arranged on the opposite two side walls of the base and the sinusoidal arm; a light inlet through hole is formed at the end of the base close to the hinge, and the light spot probe is installed on the base or the sinusoidal arm; and the laser is located at the light inlet through hole.

[0008] The high-precision small-angle generating device based on optical path folding amplification provided by the application can generate a micro angle change by driving the sinusoidal arm to rotate around the hinge through the exciter in the working process, the light emitted by the laser is reflected on the reflection modules between the sinusoidal arm and the base for many times, the position of the light spot is captured by the probe, the coefficient is multiplied by the displacement change of the light spot to obtain the changed angle, the measurement of the angle is realized, and the generated micro angle can be accurately measured. The application can skillfully utilize the principle of multiple reflections of light, can amplify the light spot position change caused by the micro angle change through simple combination of optical elements, greatly reduces the requirement for the detection precision of the light spot position, and greatly reduces the requirement for the precision of the probe. Before the measurement of the angle, the coefficient is calibrated. When the coefficient is calibrated, the exciter is only replaced by a standard gauge block with different thickness, and the position of the light spot is recorded, so that the calibration of the coefficient is realized. The coefficient is calibrated through the gauge block, the incident angle of the light path and the reflection times do not need to be measured, the calibration method is simpler, and the method has high repeatability and reliability. The application can realize the measurement of the angle without depending on the precision of the exciter, the requirement for the precision of the exciter is lower, which makes the device more flexible and adaptable in actual application, reduces the selection requirement of the exciter, and improves the feasibility of the measurement method.

[0009] Further, the outgoing light of the laser passes into the space between the base and the sinusoidal arm at a certain angle from the light inlet through hole, and the outgoing light is detected by the probe after several reflections between the reflection modules of the base and the reflection modules of the sinusoidal arm. The application utilizes the principle of multiple reflections of light, so that the incident light is reflected many times between the base and the sinusoidal arm, the light spot position change caused by the micro angle change can be amplified through simple combination of optical elements, the requirement for the detection precision of the light spot position is greatly reduced, and the requirement for the precision of the probe is greatly reduced.

[0010] Further, one side of the base and the sine arm provided with the light reflection module is a smooth plane; the light reflection module includes a light reflection film or a plane mirror. The light reflection film can be formed by plating a light reflection material on the surface of the base and the sine arm to form a thin film, thereby achieving the light reflection function.

[0011] Further, the hinge is a flexible hinge; the flexible hinge body is a rectangular cuboid, and opposite two faces of the flexible hinge body are respectively provided with grooves, the groove bottom end face is in the form of a circular arc with a radius R, the distance between the two circular arc apexes is the flexible thickness d of the flexible hinge, and the two circular arc center axes are perpendicular to the flexible thickness. The flexible hinge has high precision, good stability and a simple motion equation, can be applied to small-range angle flip adjustment, and has the advantages of no mechanical empty return, simple structure and easy manufacturing. The flexible hinge has the advantages of compact structure, easy manufacturing, simple shape, large rigidity range, high precision and no friction, and can ensure stable rotation center during rotation, thereby improving the angle measurement precision.

[0012] Further, the base, the flexible hinge and the sine arm are integrally formed. The integrated design of the sine arm, the flexible hinge and the base reduces the disassembly and assembly times of the parts, and reduces the measurement error and error accumulation; the integrated design can use fewer parts and simpler structure, and has higher reliability compared with the traditional instrument.

[0013] Further, the base, the flexible hinge and the sine arm are made of a material with a thermal expansion coefficient less than 10 -7 / K. The use of a material with a low or zero thermal expansion coefficient can avoid the influence of temperature fluctuations in the environment, enhance the measurement stability of the device, and improve the measurement precision.

[0014] Further, the base and the sine arm are arranged in parallel. The parallel arrangement of the base and the sine arm as the preferred embodiment of the application facilitates the calibration of the initial coefficient and the installation of each element; the base and the sine arm can also be assembled at a certain angle.

[0015] Further, the sine arm is provided with a spherical protrusion, and the sine arm contacts the exciter through the spherical protrusion. The sine arm contacts the exciter through the spherical protrusion, so that there is only one contact point.

[0016] Further, a column protruding towards the base side is arranged on the sine arm, and the spherical protrusion is arranged at the bottom of the column; the column, the spherical protrusion and the sine arm are integrally formed.

[0017] Further, the reflecting mirror is arranged in parallel with the rotation axis of the hinge and in perpendicular to the sinusoidal arm. The reflecting mirror is arranged on the top of the sinusoidal arm, i.e. on the opposite side of the spherical protrusion. When the sinusoidal arm rotates, the reflecting mirror rotates coaxially with the sinusoidal arm, so that the angle of the reflecting mirror changes with the rotation of the sinusoidal arm.

[0018] The application also provides a high-precision small-angle generating method based on optical path folding amplification. The method uses the high-precision small-angle generating device based on optical path folding amplification described above, drives the sinusoidal arm to rotate around the hinge by a certain angle Δα by the exciter, emits the outgoing light by the laser, and the outgoing light is emitted from the light inlet hole at a certain angle between the base and the sinusoidal arm, and after several reflections between the reflecting module of the base and the reflecting module of the sinusoidal arm, is finally detected by the detector. The generated angle Δα and the displacement change Δx of the light spot satisfy:

[0019] Δα=kΔx

[0020] In the formula, Δx represents the displacement change of the light spot on the detector when the exciter drives the sinusoidal arm to rotate around the hinge, and k represents the coefficient.

[0021] When the high-precision small-angle generating device based on optical path folding amplification is used, the following steps are included:

[0022] Calibration of the coefficient k: replace the exciter with a standard gauge block of different type to change the height Δh, and record the displacement change Δx of the light spot, and calculate the value of the coefficient k according to the following formula:

[0023]

[0024] In the formula, Δh represents the height difference between the two different types of gauge blocks; and L represents the distance between the contact point of the sinusoidal arm and the gauge block and the rotation point of the hinge.

[0025] Angle measurement: replace the exciter back to the base, and according to the displacement change Δx of the light spot detected by the detector, measure the angle Δα generated by the excitation of the sinusoidal arm.

[0026] The application provides a high-precision small-angle generation method based on optical path folding amplification, and the method comprises the following steps: first, the exciter is replaced by a standard gauge block with different sizes, and the displacement change of the light spot is recorded to calibrate the coefficient, so that the difficulty of accurately knowing the incident angle and the number of reflections of the folded light path in the traditional method is avoided, the calibration method is simple to operate, and the method has high repeatability and reliability; after the coefficient is calibrated, the exciter is installed; during measurement, the laser is turned on, the incident light is emitted from the light inlet hole of the base, the incident light is reflected between the base and the sine arm, and finally the position of the light spot is recorded by the detector; the exciter is adjusted to drive the sine arm to rotate around the flexible hinge, so that the angle is generated, the changed light spot position is recorded by the detector, the coefficient is multiplied by the displacement change of the light spot, the changed angle is obtained, and the measurement of the angle is realized.

[0027] Compared with the prior art, the application has the following beneficial effects:

[0028] 1. The high-precision small-angle generation device and method based on optical path folding amplification ingeniously utilize the multiple reflection principle of light, can amplify the light spot position change generated by the small-angle change through simple optical element combination, greatly reduce the demand for light spot position detection accuracy, and greatly reduce the accuracy requirement of the detector.

[0029] 2. The high-precision small-angle generation device and method based on optical path folding amplification can calibrate the amplification multiple of the folded light path to the angle through simple gauge block combination and measurement, avoid the difficulty of accurately knowing the incident angle and the number of reflections of the folded light path in the traditional method, and the calibration method is simple to operate and has high repeatability and reliability.

[0030] 3. The high-precision small-angle generation device and method based on optical path folding amplification can realize the measurement of the angle without depending on the accuracy of the exciter, the accuracy requirement of the exciter is low, the device has higher flexibility and adaptability in actual application, the selection requirement of the exciter is reduced, and the feasibility of the measurement method is improved.

[0031] 4. The high-precision small-angle generating device and method based on optical path folding and amplification of the present invention adopts an integrated structure of base, spring and sine arm. Compared with commonly used high-precision small-angle generator equipment, it reduces the complexity of the system, simplifies the measurement operation, and increases the stability of the measurement results. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the high-precision small-angle generation device based on optical path folding and amplification according to the present invention; the arrows in the figure indicate the incident light reflection path;

[0033] Figure 2 This is a schematic diagram of the hinge component of the present invention;

[0034] Figure 3 This is a schematic diagram of the angle generating device in Embodiment 1;

[0035] Figure 4 This is a schematic diagram illustrating the principle of optical path reversal in Example 1. The arrows in the diagram represent the optical path.

[0036] In the attached diagram: 1. Laser; 2. Base; 3. Sine arm; 4. Hinge; 5. Detector; 6. Exciter; 7. Mirror; 8. Light inlet aperture; 9. Spherical protrusion; 10. Groove. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0038] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0039] Example 1

[0040] This embodiment is an example of a high-precision small-angle generation device based on optical path folding and amplification, such as... Figure 1As shown in the figure, it comprises a laser 1, a base 2, a sinusoidal arm 3, a hinge 4, a detector 5 for detecting the position of the light spot, an exciter 6 for generating a tiny displacement, and a mirror 7; one end of the sinusoidal arm 3 is rotationally connected to one end of the base 2 through the hinge 4, the exciter 6 is installed on the other end of the base 2, the driving end of the exciter 6 is in contact with the other end of the sinusoidal arm 3, the mirror 7 is installed on the sinusoidal arm 3, the exciter 6 drives the sinusoidal arm 3 to rotate around the rotation center of the hinge 4, thereby causing the mirror 7 to change in angle; the two side walls of the base 2 opposite to the sinusoidal arm 3 are each provided with a planar light reflection module, a light inlet through hole 8 is formed on the end of the base 2 close to the hinge 4, and the light spot detector 5 is installed on the base 2 or the sinusoidal arm 3; the laser 1 is located at the light inlet through hole 8.

[0041] In the embodiment, the outgoing light of the laser 1 enters between the base 2 and the sinusoidal arm 3 at a certain angle from the light inlet through hole 8, and is detected by the detector 5 after being reflected for several times between the light reflection modules of the base 2 and the sinusoidal arm 3. The present application utilizes the principle of multiple reflections of light, so that the incident light is reflected multiple times between the base 2 and the sinusoidal arm 3, and through the simple combination of optical elements, the change in the position of the light spot caused by the tiny angle change can be amplified, thereby greatly reducing the requirement for the detection precision of the position of the light spot and greatly reducing the requirement for the precision of the detector 5.

[0042] In the embodiment, the side of the base 2 and the sinusoidal arm 3 provided with the light reflection module is a smooth plane; the light reflection module comprises a light reflection film or a plane mirror. The light reflection film can be formed by plating a light reflection material on the surface of the base 2 and the sinusoidal arm 3 to form a thin film, thereby realizing the reflection of light.

[0043] In the embodiment, as shown in the figure, Figure 2 The hinge 4 is a flexible hinge; the main body of the flexible hinge is a rectangular cuboid, recesses 10 are respectively formed on the two opposite sides of the main body of the flexible hinge, the bottom end surface of the recess 10 is in the shape of a circular arc with a radius of R, the distance between the two top points of the circular arcs is the flexible thickness d of the flexible hinge, and the center axes of the two circular arcs are perpendicular to the flexible thickness. The flexible hinge has high precision, good stability, and a simple motion equation, can be applied to the flip adjustment of a small range of angles, and has the advantages of no mechanical empty return, simple structure, and easy manufacturing. The flexible hinge structure adopted by the present application is compact, easy to manufacture, simple in shape, has a large range of stiffness, high precision, and no friction, etc.; and the flexible hinge with the structure of the present application can ensure the stability of the rotation center during rotation, thereby improving the precision of angle measurement.

[0044] In the embodiment, the base 2, the flexible hinge and the sinusoidal arm 3 are integrally formed. The integrated design of the sinusoidal arm 3, the flexible hinge and the base 2 reduces the disassembly and assembly times of the parts, and reduces the measurement error and the accumulation of errors. The integrated design can use fewer parts and simpler structure, and has higher reliability compared with the traditional instrument.

[0045] In the embodiment, the base 2, the flexible hinge and the sinusoidal arm 3 are made of a material with a thermal expansion coefficient less than 10 -7 / K. The use of a material with a low or zero thermal expansion coefficient can avoid the influence of temperature fluctuations in the environment, enhance the measurement stability of the device, and improve the measurement accuracy.

[0046] In the embodiment, the base 2 is arranged in parallel with the sinusoidal arm 3. The parallel arrangement of the base 2 and the sinusoidal arm 3 is a preferred embodiment of the present application, which facilitates the calibration of the initial coefficient and the installation of each element. The base 2 and the sinusoidal arm 3 can also be assembled at an angle.

[0047] In the embodiment, the sinusoidal arm 3 is provided with a spherical protrusion 9, and the sinusoidal arm 3 contacts the exciter 6 through the spherical protrusion 9. The use of the spherical protrusion 9 to contact the exciter 6 ensures that there is only one contact point. A column protruding towards the base 2 is arranged on the sinusoidal arm 3, and the spherical protrusion 9 is arranged at the bottom of the column. The column, the spherical protrusion 9 and the sinusoidal arm 3 are integrally formed.

[0048] In the embodiment, the reflecting mirror 7 is arranged in parallel with the rotation axis of the hinge 4 and perpendicularly to the sinusoidal arm 3. The reflecting mirror 7 is arranged at the top of the sinusoidal arm 3, i.e. on the opposite side of the spherical protrusion 9. When the sinusoidal arm 3 rotates, the reflecting mirror 7 rotates coaxially with the sinusoidal arm 3, so that the angle of the reflecting mirror 7 changes with the rotation of the sinusoidal arm 3.

[0049] Working principle:

[0050] As shown in Figure 3 , O is the rotation point, |OB| is the length of the sinusoidal arm (in the embodiment, it is actually the distance between the contact point of the sinusoidal arm and the block and the rotation point of the hinge), and |AB| is the height of the sinusoidal arm and the reference surface. According to the sine theorem, the following equation can be obtained:

[0051]

[0052] According to the inverse sine operation, the angle α generated by the small-angle generator is:

[0053]

[0054] In the actual use scenario of the high-precision small-angle generator, the generated angle α is generally very small, so formula (2) can be simplified as:

[0055]

[0056] The height h is changed to generate a small angle, and the length L needs to be kept stable to generate the small angle accurately.

[0057] A schematic diagram of the light path folding and amplification technology is shown in FIG. 1. Figure 4 As shown in FIG. 1, the distance between the incident point C and the rotation axis O is |OC|, the distance between the light spot position D and the rotation axis O is |OD|, the angle between the incident light and the bottom surface is θ, and the angle between the light ray to the D point and the bottom surface detector plane is The angle between the bottom surface and the upper mirror is α, and n is the total number of light spots on the upper and lower surfaces. According to the geometric relationship, the following can be calculated:

[0058]

[0059] Where n represents the number of reflections on the lower bottom surface. In the case of a small angle, it can be approximated as:

[0060]

[0061] When the range changes slightly, the relationship between the angle change Δα and the displacement change Δx of the light spot is:

[0062]

[0063] According to formula (6), the measurement of the angle change can be converted to the measurement of the light spot position.

[0064] According to formula (6), it can be known that when the angle range changes slightly, the generated angle Δα and the displacement change Δx of the light spot satisfy:

[0065] Δα=kΔx (7)

[0066] According to formula (7), when using the device provided in the embodiment, in use, in order to avoid accurate measurement of the number of reflections, the length of the light path and the incident angle and other parameters, only the coefficient k needs to be calibrated, and the angle change measurement can be converted to the light spot position change measurement.

[0067] According to the calculation, when the laser incident position is determined, n<300, and Δα is a small angle, k is basically a constant, so k can be calibrated. The calibration method is as follows: the actuator 6 is replaced with a standard gauge block, and different thickness gauge blocks are replaced to change the height Δh, the length L between the sine arm contact point and the hinge rotation point is measured, and the displacement change Δx of the light spot is recorded. According to formula (3) and formula (7), the following can be obtained:

[0068]

[0069] According to formula (8), the calibrated coefficient k is obtained, and then the actuator 6 is installed. The angle measurement generated by the actuator 6 pushing the sinusoidal arm 3 can be realized according to the spot displacement Δx of the detector.

[0070] The high-precision small-angle generating device based on light path folding amplification provided by the embodiment can generate a small angle change in the working process, the actuator 6 pushes the sinusoidal arm 3 to rotate around the hinge 4, the light emitted by the laser 1 is reflected multiple times on the reflective module between the sinusoidal arm 3 and the base 2, the position of the light spot is captured by the detector 5, the coefficient is multiplied by the displacement change of the light spot to obtain the changed angle, the angle measurement is realized, and the generated small angle can be accurately measured. The present application can cleverly utilize the principle of multiple reflections of light, and through the combination of simple optical elements, the change of the light spot position caused by the amplification of the small angle change can be greatly reduced, and the requirement for the detection accuracy of the light spot position is greatly reduced. The accuracy requirement of the detector 5 is greatly reduced; before measuring the angle, the coefficient is calibrated, and when calibrating the coefficient, the actuator 6 is replaced by a standard gauge block with different thicknesses, and the position of the light spot is recorded, so that the calibration of the coefficient can be realized. The present application calibrates the coefficient by using the gauge block, without measuring the incident angle and the number of reflections of the light path, so that the calibration method is simpler, and the present application has high repeatability and reliability. The present application can realize the measurement of the angle without depending on the accuracy of the actuator 6, and the accuracy requirement of the actuator 6 is lower, which makes the device more flexible and adaptable in actual application, reduces the selection requirement of the actuator 6, and improves the feasibility of the measurement method.

[0071] Embodiment two

[0072] The present embodiment is a first embodiment of a high-precision small-angle generating method based on light path folding amplification, which adopts the high-precision small-angle generating device based on light path folding amplification provided by the first embodiment, drives the sinusoidal arm 3 to rotate around the hinge 4 by the actuator 6, emits the outgoing light by the laser 1, and the outgoing light is emitted from the light inlet hole 8 to the space between the base 2 and the sinusoidal arm 3 at a certain angle, and is reflected for several times between the reflective module of the base 2 and the reflective module of the sinusoidal arm 3, and finally is detected by the detector 5. The generated angle Δα and the displacement change Δx of the light spot satisfy:

[0073] Δα=kΔx

[0074] In the formula, Δx represents the displacement change of the light spot on the detector 5 when the actuator 6 drives the sinusoidal arm 3 to rotate around the hinge 4; and k represents the coefficient.

[0075] When the high-precision small-angle generating device based on light path folding amplification is used, the following steps are included:

[0076] Calibration coefficient k: replace the exciter 6 with a standard gauge block of different size to change the height Δh, and record the displacement change Δx of the light spot, and calculate the value of the coefficient k according to the following formula:

[0077]

[0078] In the formula, Δh represents the height difference between the two different sizes; L represents the distance value between the contact point of the sine arm 3 and the gauge block and the rotation point of the hinge 4, that is Figure 3 In the formula, |OB| is the length value;

[0079] Angle measurement: replace the exciter back to the base, and measure the angle Δα generated by the excitation of the sine arm according to the displacement change Δx of the light spot detected by the detector.

[0080] The working principle of this embodiment is similar to that of embodiment one, which will not be repeated here.

[0081] The high-precision small-angle generation method based on light path folding amplification provided by the embodiment first calibrates the coefficient by replacing the exciter 6 with a standard gauge block of different sizes to record the displacement change of the light spot, avoids the difficulty of needing to accurately know the incident angle and the number of reflections of the folded light path in the traditional method, and has high repeatability and reliability. After the coefficient is calibrated, the exciter 6 is installed. When measuring, first turn on the laser 1, and the laser is emitted from the light inlet hole 8 of the base 2, the incident light will be back and forth between the base 2 and the sine arm 3, and finally the detector 5 records the light spot position; adjust the exciter 6 to make the exciter 6 push the sine arm 3 to rotate around the rotation point of the flexible hinge, thereby realizing the generation of angle, and the changed light spot position is recorded by the detector 5, the coefficient is multiplied by the displacement change of the light spot, the changed angle is obtained, and the measurement of the angle is realized. The present application ingeniously utilizes the principle of multiple reflection of light, and through the combination of simple optical elements, the light spot position change generated by the amplification of small angle change is realized, which greatly reduces the demand for light spot position detection accuracy and greatly reduces the precision requirement of the detector 5. The present application does not depend on the precision of the exciter 6 to realize the measurement of the angle, and the precision limitation of the exciter 6 is lower, which makes the device more flexible and adaptable in actual application, reduces the selection requirement of the exciter 6, and improves the feasibility of the measurement method.

[0082] Embodiment three

[0083] The second embodiment of the high-precision small-angle generation method based on light path folding amplification is similar to the second embodiment, and in the embodiment, it is assumed that the changed angle Δα is 1000 μrad, the distance value L of the contact point of the sine arm 3 to the rotating point of the hinge 4 to the length of the length L is 400.0 mm, and the height difference of the front and rear two length blocks is Δh=400 μm. The standard uncertainty of the typical high-precision length block is 0.02 μm, and the uncertainty of the angle change Δα introduced is 0.05 μrad. The uncertainty of L is 0.2 mm, and the uncertainty of the angle change Δα introduced is 0.5 μrad. At this time, the error introduced by the length block can be ignored compared with the error introduced by the length L. Through reasonable design, the light spot displacement Δx on the detector 5 can be realized as 5 mm. The position sensitive detector 5 (PSD) is used to detect the light spot position, and the typical detection accuracy of the position sensitive detector 5 is 1.0 μm, so that the calibration coefficient k is 0.2 rad / m, and the corresponding standard uncertainty is 100 μrad / m. After the length block is replaced by the actuator 6, the light spot displacement is measured, and the formula (7) in the formula embodiment one is brought into the formula to realize the small-angle change and measurement with an uncertainty better than 0.05 μrad within 100 μrad and an uncertainty better than 0.5 μrad within 1000 μrad. According to different angle measurement requirements, the length block can be used for calibration in different ranges to meet the measurement requirements.

[0084] In the specific contents of the above specific embodiments, any inconsistent combination of technical features can be combined, and in order to make the description simple, all possible combinations of the above technical features are not described, but as long as the combination of these technical features does not exist, it should be considered as the scope of the present application.

[0085] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not limitations on the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments need not and cannot be exhausted. Any modification, equivalent replacement and improvement made within the spirit and principles of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A high-precision small-angle generating device based on optical path folding amplification, characterized in that, The application relates to a high-precision small-angle generating device based on optical path folding and amplification, which comprises a laser (1), a base (2), a sinusoidal arm (3), a hinge (4), a detector (5) for detecting the position of a light spot, an exciter (6) for generating a tiny displacement, and a mirror (7); one end of the sinusoidal arm (3) is rotationally connected with one end of the base (2) through the hinge (4), the exciter (6) is installed at the other end of the base (2), the driving end of the exciter (6) is in contact with the other end of the sinusoidal arm (3), the mirror (7) is installed on the sinusoidal arm (3), the exciter (6) drives the sinusoidal arm (3) to rotate around the rotation center of the hinge (4), thereby driving the mirror (7) to change the angle; the opposite two side walls of the base (2) and the sinusoidal arm (3) are each provided with a planar light reflection module, a light inlet through hole (8) is formed at the end of the base (2) close to the hinge (4), and the detector (5) is installed on the base (2) or the sinusoidal arm (3); the laser (1) is located at the light inlet through hole (8).

2. The high-precision small-angle generating device based on optical path folded amplification according to claim 1, characterized in that, The outgoing light of the laser (1) enters between the base (2) and the sinusoidal arm (3) at a certain angle from the light inlet through hole (8), the outgoing light is reflected for several times between the light reflection modules of the base (2) and the sinusoidal arm (3), and is finally detected by the detector (5).

3. The high-precision small-angle generating device based on optical path folded amplification according to claim 2, characterized in that, The side of the base (2) and the sinusoidal arm (3) provided with the light reflection module is a smooth plane; the light reflection module comprises a light reflection film or a plane mirror.

4. The high-precision small-angle generating device based on optical path folded amplification according to claim 2, characterized in that, The hinge (4) is a flexible hinge; the main body of the flexible hinge is a rectangular cuboid, recesses (10) are respectively formed in the opposite two faces of the main body, the bottom end face of the recess (10) is in the shape of a circular arc with a radius R, the distance between the two top points of the circular arcs is the flexible thickness d of the flexible hinge, and the two circular arc center axes are perpendicular to the flexible thickness.

5. The high-precision small-angle generation device based on optical path folded amplification according to claim 4, characterized in that, The base (2), the flexible hinge and the sinusoidal arm (3) are integrally formed.

6. The high-precision small-angle generation device based on optical path folded amplification according to claim 4, characterized in that, The base (2), the flexible hinge and the sinusoidal arm (3) are made of a material having an expansion coefficient less than 10 -7 / K.

7. The high-precision small-angle generation device based on optical path folded amplification according to claim 4, characterized in that, The base (2) and the sinusoidal arm (3) are arranged in parallel.

8. The high-precision small-angle generating device based on optical path folded amplification according to any one of claims 1 to 7, characterized in that, A spherical protrusion (9) is arranged on the sinusoidal arm (3), and the sinusoidal arm (3) is in contact with the exciter (6) through the spherical protrusion (9).

9. The high-precision small-angle generating device based on optical path folded amplification according to any one of claims 1 to 7, characterized in that, The mirror (7) is arranged in parallel with the rotation axis of the hinge (4) and in perpendicular to the sinusoidal arm (3).

10. A high-precision small-angle generation method based on optical path folding amplification, characterized in that, The high-precision small-angle generating device based on optical path folding and amplification is used, the sinusoidal arm (3) is driven by the exciter (6) to rotate around the hinge (4) by a certain angle Delta alpha, the laser (1) emits outgoing light, the outgoing light enters between the base (2) and the sinusoidal arm (3) at a certain angle from the light inlet through hole (8), is reflected for several times between the light reflection modules of the base (2) and the sinusoidal arm (3), and is finally detected by the detector (5); the generated angle Delta alpha and the displacement change Delta x of the light spot satisfy the following formula: Delta alpha = k Delta x. In the formula, Δx represents the displacement change of the light spot on the detector (5) when the actuator (6) drives the sine arm (3) to rotate around the hinge (4), and k represents a coefficient. When using a high-precision small-angle generating device based on optical path folding amplification, the following steps are included: Calibration coefficient k: replace the actuator (6) with a standard gauge block of a different model to change the height Δh, and record the displacement change Δx of the light spot, and calculate the value of the coefficient k according to the following formula: In the formula, Δh represents the height difference between the two different models of the gauge block; L represents the distance between the contact point of the sine arm (3) and the rotating point of the hinge (4); Angle measurement: replace the actuator (6) back to the base (2), and according to the displacement change Δx of the light spot detected by the detector (5), measure the angle Δα generated by the rotation of the actuator (6) pushing the sine arm (3).

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