WO2018068225A1

WO2018068225A1 - Measurement apparatus and measurement method for surface-shape error of rotating-axis symmetric curved surface

Info

Publication number: WO2018068225A1
Application number: PCT/CN2016/101894
Authority: WO
Inventors: 彭石军; 苗二龙; 高松涛; 曲艺; 苏东奇; 隋永新; 杨怀江
Original assignee: 中国科学院长春光学精密机械与物理研究所
Priority date: 2016-10-12
Filing date: 2016-10-12
Publication date: 2018-04-19

Abstract

Provided is a measurement apparatus for a surface-shape error of a rotating-axis symmetric curved surface, the apparatus comprising: a base (1); a rotating platform (3) arranged on the base and used for driving a measured object (9) to rotate around a rotating axis; a laser measurement system (8) used for scanning and sampling a measured surface of the measured object (9) during the rotating process of the measured object (9) so as to obtain data of a plurality of sampling points; and a calculation apparatus used for calculating a surface-shape error based on geometric parameters of the measured surface and the data of the plurality of sampling points. Also provided is a measurement method for a surface-shape error of a rotating-axis symmetric curved surface. The measurement apparatus and method can achieve zero-damage measurement.

Description

Measuring device and measuring method for surface error of rotating axisymmetric curved surface

Technical field

The invention relates to the field of optical measurement, in particular to a rotating axisymmetric curved surface shape error measuring device and a measuring method.

Background technique

In the optical system, the lens and the mirror are mostly in the form of plane and spherical surface. The reason is that these simple forms of surface processing and detection are easy, mass production can be achieved, and high-precision surface shape requirements are easily achieved, especially The emergence of a high-precision surface detection interferometer greatly reduces the difficulty of high-precision planar and spherical surface detection. At the same time, the unique optical properties of the aspheric surface have attracted people's attention and gradually replaced the position of the sphere and the plane, playing an increasingly important role in the optical system.

Among them, the cylindrical surface is a special aspherical surface, and its meridional and sagittal planes have different optical powers, and are widely used in the field of scientific research in strong laser systems and synchrotron radiation beam lines, especially in high-power laser resonators. In high-precision testing instruments and devices such as cavity and long-distance line interferometers, the accuracy of cylindrical surface is getting higher and higher. For high-precision optical components, the deviation between the actual surface quality and the ideal surface quality of the surface should be less than a few points. One of the wavelengths. In the field of daily life, cylindrical surfaces are also used in instruments that require long slit concentrating, such as line focusing systems, scanning imaging systems; cylindrical and cylindrical mirrors are also used in correcting human astigmatism. . In addition, in recent decades, synchrotron radiation, which is widely used in science, engineering, industry and agriculture, requires the design of different wire harness devices, some of which are cylindrical.

High-precision detection is the basis and guarantee for high-precision machining of optical components, and is a necessary condition for high-precision machining. In order to produce a high-precision cylindrical surface that meets the requirements, it is necessary to solve the problem of high-precision detection of the cylindrical surface. However, due to the special optical characteristics of the cylindrical surface, it is impossible to perform high-precision detection of the surface quality by using general inspection. So far, there are many methods for detecting cylindrical surfaces, including the template method, the profiler method, the auxiliary plane method, the fiber method, and the standard cylinder method. These methods have their own shortcomings, which restrict the high-precision detection of the cylindrical surface. Both the template method and the profiler detection method are contact type detection, which is easy to scratch the cylindrical surface to be tested, and the measurement accuracy is low, which is only on the order of micrometers; the auxiliary plane method cannot detect the asymmetric deviation in the cylindrical surface shape; Difficult to install and adjust, poor practicality, affecting the accuracy of cylindrical surface detection; standard cylindrical method requires standard cylinder, its price is equivalent Expensive and difficult to process.

Therefore, how to develop a non-contact high-precision cylindrical measuring device to achieve non-damage detection has become an urgent problem to be solved.

Summary of the invention

In view of the above technical problems, in order to overcome the deficiencies of the prior art described above, the present invention proposes a high-precision cylindrical surface shape error measuring device and a measuring method.

According to an aspect of the invention, there is provided a measuring device for a rotational axisymmetric curved surface shape error, the measuring device comprising a base; a turntable disposed on the base for driving the object to be rotated about the rotating shaft; the laser measuring system And in the process of rotating the measured object, scanning and sampling the measured surface of the measured object to obtain a plurality of sampling point data; and calculating means, based on geometric parameters and locations of the measured surface Several sampling point data are described to calculate the surface shape error.

According to another aspect of the present invention, a method for measuring a surface error of a rotational axisymmetric curved surface is provided. The measuring device comprises the following steps: Step A: The computing device obtains an ideal shape based on geometric parameters of the measured surface; Step B: Control The device controls the rotation of the rotating table in the measuring device, and controls the laser measuring system to scan and sample the measured surface to obtain the measurement data of each sampling point; Step C: the computing device obtains the measured surface shape based on the measured data of the sampling point; Step D: The computing device obtains a face shape error based on the ideal face shape and the measured face shape.

It can be seen from the above technical solutions that the present invention has the following beneficial effects:

The invention adopts the shape error measuring device of the invention, and realizes non-destructive high-precision detection on special curved surfaces such as cylindrical surfaces by using a laser measuring system or the like;

The multi-wavelength laser measurement system includes an X-direction reference displacement measurement interferometer and a Z-direction reference displacement measurement interferometer to accurately calculate the displacement of the target probe in the X and Z directions;

The target measurement module can be rotated in a horizontal plane to facilitate small-caliber inner and large-diameter measurement switching without the need to design long Z-directional mirrors;

The base includes a partition plate, a vibration isolation table and a vibration isolation leg to avoid external influence on the measurement process;

The centering axis of the measured cylindrical surface and the like are coincident with the rotating shaft of the turntable by using a leveling and aligning workbench combined with a turntable and a laser measuring system;

The laser measurement system uses a multi-wavelength laser for measurement to improve measurement accuracy.

Miniaturization of the device is achieved by using a small-sized interferometer and a target probe.

DRAWINGS

1 is a schematic view of a surface shape error measuring device according to an embodiment of the present invention;

Figure 2 is a side elevational view of the main structure of Figure 1;

3 is a schematic diagram of a measuring optical path of the surface error measuring device of FIG. 1;

4 is a specific structure and optical path diagram of the target measuring interferometer of FIG. 1;

Figure 5 is a schematic diagram of the principle of a dual-wavelength interferometer;

FIG. 6 is a flowchart of a measurement method according to an embodiment of the present invention.

[main components]

1-base; 2-frame; 3-turntable; 4-leveling and aligning workbench;

5-two-dimensional motion table; 6-cantilever; 7-extension rod; 8-laser measurement system;

9-measured object; 11-control box; 12-computer; 101-side plate; 102-isolation table;

103-isolation leg; 201-beam; 202-bracket; 601-cantilever first end;

602-the second end of the cantilever; the first end of the 701-extension rod; the second end of the 702-extension rod;

800-laser; 801-first beam splitter; 802-second beam splitter;

803-first mirror; 804-Z displacement displacement interferometer; 805-X displacement displacement interferometer;

806-second mirror; 807-target measuring interferometer; 808-target probe;

809-Z direction reference probe; 810-X direction reference probe; 811-Z direction mirror;

812-X-direction mirror.

detailed description

Some embodiments of the invention will be described more fully hereinafter with reference to the appended drawings, in which some, but not all, In fact, the various embodiments of the invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

The present invention will be further described in detail below with reference to the specific embodiments of the invention.

In order to better describe the spatial relationship between the components of the present invention, the horizontal left and right direction is defined as the X axis, the horizontal front and rear direction is defined as the Y axis, and the vertical up and down direction is defined as the Z axis.

The invention provides a surface shape error measuring device, which can be used for measuring a rotating axisymmetric curved surface such as a cylindrical surface or a conical surface. The embodiment of the present invention introduces a cylindrical surface as an example, as shown in FIG. Base 1, bracket 2, turntable 3, leveling and aligning worktable 4, two-dimensional transport The movable table 5, the laser measuring system 8, the control box 11, and the computer 12.

The pedestal 1 plays a supporting role in the whole measuring device, and includes a vibration isolation table 102 and a vibration isolation leg 103 supporting the vibration isolation table 102. The vibration isolation table 102 is used for supporting other measurement components, and the side plate 101 is disposed at one end side. It is disposed perpendicular to the vibration isolation table 102 and is used to fix a two-dimensional motion table 5 to be described later. The vibration isolation table 102 and the side plate 101 may be made of marble, stainless steel or the like, preferably a marble material, and the vibration isolation leg 103 is preferably an air-floating vibration isolation leg, which effectively reduces the influence of ambient vibration on the measurement.

The frame 2 is erected above the base 1 and includes a beam 201 and two brackets 202 supporting the beam. Both brackets 202 are disposed on the vibration isolation table 102 to support both ends of the beam 201. The frame 2 is preferably made of indium steel material. .

The turntable 3 is mounted on the vibration isolation table 102 of the base 1, and is located below the frame 2. The turntable 3 preferentially adopts an air floating turntable, which is rotatable about its axis, and has a radial end jump and an axial end jump of less than 0.05 μm.

The leveling and aligning workbench 4 is disposed on the turntable 3 for adjusting the object to be measured, reducing the tilt and eccentricity, and can be rotated by the turntable 3.

The frame 2, the turntable 3 and the leveling and aligning table 4 are coaxial, and are perpendicular to the vibration isolation table 102. The rotation axis of the turntable 3 coincides with the Z axis of the measurement coordinate system, and the upper surface of the air floating turntable 3 is set as the measurement coordinate system. The XOY plane.

The two-dimensional moving table 5 is mounted on the side plate 101, perpendicular to the upper surface of the turntable 3, and is movable along the X-axis and the Z-axis. A cantilever 6 disposed parallel to the upper surface of the turntable 3 is fixedly mounted on the two-dimensional moving table 5, the first end 601 of the cantilever 6 is fixed to the two-dimensional moving table 5, the second end 602 is located above the turntable 3, and the elongated rod 7 is parallel to The first end 701 is fixed to the second end 602 of the cantilever 6 and the second end 702 is suspended above the upper surface of the turntable 3 and directed to the upper surface of the turntable 3. The cantilever 6 and the extension rod 7 can be moved in two dimensions. The table 5 is driven to move along the X and Z axes together.

The laser measuring system 8 is provided with a two-dimensional moving table 5, a cantilever 6, an extension rod 7 and a frame 2, as shown in Figs. 2 and 3, which includes a laser 800, a first beam splitter 801, a second beam splitter 802, and a first reflection. 803, Z-direction displacement interferometer 804, Z-direction reference probe 809, X-direction displacement interferometer 805, X-direction reference probe 810, second mirror 806, target measurement interferometer 807, target probe 808, Z-direction Mirror 811, X-direction mirror 812.

The laser 800 is used to emit the detected laser light, which is fixed in the control box 11, and the outgoing laser light is guided into the measuring system by the optical fiber, and the optical fiber exit end is fixed on the cantilever 6 and the outgoing light is suspended. The arm 6 emits laser light in the longitudinal direction, that is, in the Y-axis direction. The laser 800 is a multi-wavelength laser that facilitates the measurement of absolute distances.

The first mirror 803, the second beam splitter 802, and the first beam splitter 801 are fixedly disposed on the cantilever 6, and the three are arranged in a line parallel to the Z axis from top to bottom, and the Z-direction displacement interferometer 804, The Z-direction reference probe 809, the X-direction displacement interferometer 805, and the second mirror 806 are fixed to the first end 701 of the extension rod 7, and the three are arranged in a line parallel to the Z-axis from top to bottom, and respectively The first mirror 803, the second beam splitter 802, and the first beam splitter 801 are located on a horizontal line. In this embodiment, as shown in FIG. 2, the first mirror 803 and the Z-direction displacement interferometer 804 and the second beam splitter are provided. The 802 and X-direction displacement interferometer 805, the first beam splitter 801 and the second mirror 806 are respectively located on horizontal lines parallel to the Y-axis.

The target measurement interferometer 807 and the target probe 808 are fixed to the second end 702 of the extension rod 7, wherein the target measurement interferometer 807 is located in a pair with the Z-direction displacement interferometer 804, the X-direction displacement interferometer 805, and the second mirror 806. On the straight line parallel to the Z axis, the target probe 808 and the target measurement interferometer 807 are disposed on a horizontal line. In this embodiment, on the horizontal line parallel to the X axis, the preferred target probe 808 and the target measurement interferometer 807 are designed as one. Overall, it can be rotated in the horizontal plane.

The Z-direction mirror 811 is disposed at the bottom of the beam 21 of the frame 2, opposite to the Z-direction reference probe 809 for reflecting the light of the Z-directed reference probe 809. The X-direction mirror 812 is disposed on the frame 2 side of the frame 202, and is disposed opposite to the X-direction reference probe 810 for reflecting the light of the X-direction reference probe 810. In this embodiment, the X-direction mirror 812 is disposed on the frame 2. On the left side bracket 202.

The control box 11 is connected to the turntable 3, the two-dimensional moving table 5 and the laser measuring system 8, and controls the rotation of the turntable 3, the displacement of the two-dimensional moving table 5, and the measurement of the laser measuring system 8, and acquires the measurement data of the laser measuring system 8, The measurement data is then transmitted to the computer 12 via the data line.

The computer 12 analyzes and calculates the received, and finally gives the error result of the measured surface, which specifically includes a data processing module and a comparison module, and the data processing module is configured to calculate an ideal shape based on the input geometric parameters of the measured surface. The measured surface shape is calculated based on the measured data, and the comparison module compares the measured surface shape with the ideal surface shape to determine the surface shape error and output.

When the measurement is performed by the surface error measuring device of the embodiment of the present invention, the object 9 to be measured is placed on the leveling and aligning worktable 4. In this embodiment, the object 9 to be measured is a cylinder having a circular cross section. Body, having an inner cylindrical surface, using the surface error measuring device to measure the inner circle of the object 9 The cylinder is measured. The measurement principle is as follows:

As shown in FIG. 2 and FIG. 3, the laser light L emitted from the laser 800 enters the first beam splitter 801 and is divided into two laser beams. The first laser beam L1 is reflected by the second mirror 806, and the target measuring interferometer 807 and the target probe 808 are transmitted. For measuring the absolute distance D from the inner cylindrical surface of the object 9 to be measured; the other laser beam is split by the second beam splitter 802 into a second laser beam L2 and a third laser beam L3, and the second laser beam L2 is passed through X. The displacement interferometer 805 and the X-direction mirror 812 are used to determine the X-direction displacement amount Dx of the target probe 808, and the third beam laser L3 is reflected by the first mirror 803 to the Z-direction displacement interferometer 804, and is displaced by the Z-direction. The interferometer 804 and the Z-direction mirror 811 are used to determine the Z-direction displacement amount Dz of the target probe 808. The object to be measured 9 fixed on the leveling and aligning work 4 is rotated at a constant speed around the rotating shaft by the air floating turret 3, and the movement of the target measuring head 808 is performed to realize the surface scanning of the inner cylindrical surface of the entire object to be measured. The measurement data of the plurality of sampling points are obtained, and the measurement data of the plurality of sampling points are processed by the calculation 12 and compared with the ideal cylindrical surface to determine the surface error of the cylindrical surface of the object 9 to be measured.

The target measurement interferometer 807, the X-direction displacement interferometer 805, and the Z-direction displacement interferometer 806 measure the absolute distance D from the inner cylindrical surface of the object 9 to be measured, the X-direction displacement amount Dx of the target probe 808, and the target probe 808. The core device of the Z-direction displacement amount Dz is exemplified by the target measurement interferometer 807. The specific structure is shown in FIG. 4, and the incident light enters the interferometer 807 and is reflected and transmitted by the spectroscope in the interferometer to be divided into two parts. The reflected portion enters the target probe 808 to become measurement light. After being concentrated by the converging lens in the target probe, it converges to a point on the surface of the object to be tested 9, and is then reflected by the surface to be measured 9 and passes through the target probe. The beam splitter of the interferometer 807; the incident lens condenser lens of the transmissive portion converges and illuminates the reference plane and is returned as the reference light, entering the beam splitter of the interferometer 807. The reference light and the measurement light interfere in the beam splitter of the interferometer 807 to form interference light which is received by the photoelectric converter and forms an interference signal. The surface distance variation of the target probe 808 to the measured object 9 can be obtained by changing the number of interference signal pulses. The specific working principle is the principle of multi-wavelength interference.

The principle of multi-wavelength interference is to synthesize a plurality of different wavelengths to form a composite wavelength, which is larger than any one of the wavelength values. By using this larger synthetic wavelength as a measuring scale, the absolute distance measurement can be greatly increased. range. As shown in FIG. 5, taking dual wavelengths as an example, the two wavelengths emitted by the laser are λ ₁ and λ ₂ respectively incident on the interferometer, and both wavelengths pass through the two optical arms of the interferometer, and are received by the photodetectors at the output end.

Let the wavelengths of the two light waves be λ ₁ and λ ₂ (λ ₁ > λ ₂ ), and the measured distance (the two-arm difference of the interferometer) is L. When n=1, after the two wavelengths are measured separately, the following formula holds:

φ ₁ , φ ₂ are the phase differences measured at the wavelengths λ ₁ and λ ₂ respectively, and the difference between the two equations is obtained:

As can be seen from the above equation, Δφ is a function of λ _s , and λ _s can be expressed as λ _s = λ ₁ λ ₂ /(λ _{1 -} λ ₂ ), and λ _s is an equivalent synthetic wavelength. It can be seen that the biggest difference between multi-wavelength interferometry and single-wavelength interferometry is that the phase change of the measured distance is determined by multiple wavelengths simultaneously, thus producing a phase difference determined by their combined wavelength λ _s . Δφ, the entire measurement process is equivalent to being completed by this larger measurement wavelength λ _s .

To calculate the relationship between the measured distance L and the two-wavelength phase measurement of the detector, the following method can be used to obtain a single wavelength measurement:

L=(λ ₁ /2)(m ₁ +ε ₁ ) (4)

L=(λ ₂ /2)(m ₂ +ε ₂ ) (5)

In the above formula, m ₁ and m ₂ are integer parts corresponding to the interference order of the wavelengths λ ₁ and λ ₂ , and ε ₁ and ε ₂ correspond to the fractional part. Let m _s =m ₂ -m ₁ , ε _s =ε ₂ -ε ₁ , then:

L=(λ _s /2)(m _s +ε _s ) (6)

In the above formula, λ _s = λ ₁ λ ₂ / (λ _{1 -} λ ₂ ), and m _s and ε _s are the integer part and the fractional part of the λ _s interference order, respectively. Let the measured value of the measured distance be L _c and the uncertainty is ΔL _p . If the appropriate laser wavelength is selected so that the coarse measurement uncertainty satisfies the condition ΔL _c <(λ _s /4-ΔL _p ), then only The interference level integer part m _s can be obtained by calculation:

The fractional phases ε ₁ and ε _{2 of the} two wavelengths are calculated by the signal demodulation circuit to obtain the value of ε _s , and the distance L can be accurately calculated by combining the equation (6).

The structure of the Z-direction displacement measuring interferometer (804) and the X-direction displacement measuring interferometer (805) in this embodiment is consistent with the structure of the target measuring interferometer (807), and the difference is that the focal length of the reference measuring head is different, thereby The working distance of the probe is different and the measuring range is different.

In the measuring apparatus of the present embodiment, the intensity of the three laser beams L1, L2, and L3 may be the same or different, and it is preferable that the three laser beams have the same intensity. At this time, the first beam splitter 801 is preferably a 33/67 beam splitter, and the second beam splitter is a 50/50 beam splitter.

In order to make the measured inner diameter of the cylindrical surface as small as possible, the first beam splitter 801, the second beam splitter 802, the first mirror 803, the Z-direction displacement interferometer 804, the Z-direction reference probe 809, the X-direction displacement interferometer 805, The X-direction reference probe 810, the second mirror 806, the target measurement interferometer 807, and the target probe 808 all adopt a miniaturized design, and the dimensions are all less than 10 mm×10 mm×10 mm, wherein the target probe 808 is preferably a converging lens and an optical axis. Parallel to the X-axis direction, the maximum diameter is less than 10 mm, the focal length is less than 500 μm, the focal point is less than 6 μm, and the NA is greater than 0.5.

The target probe 808 is integral with the target measuring interferometer 807 and can be rotated in a horizontal plane, preferably 180°. This rotatable design facilitates measurement switching between a small-caliber inner cylindrical surface and a large-diameter outer cylindrical surface without design. The long Z-direction displacement measures the reference mirror 6. By properly controlling the X-direction translational motion of the two-dimensional motion table 5, the distance from the condenser lens 808 to the measured surface can be kept substantially constant, which is the basic guarantee for the high-precision cylindrical surface measurement.

The embodiment of the invention further provides a surface shape error measurement method, which adopts the foregoing measurement device, and includes the following steps, as shown in FIG. 6:

Step A: placing the measured object 9 on the leveling and aligning workbench 4 to level the aligning, so that the axis of the measured cylindrical surface of the measured object 9 coincides with the rotating shaft of the turntable 3;

Specifically, first, the measuring device is powered on, and the control box 11 is activated. After the system is stabilized, the cylindrical surface 9 to be tested is placed on the leveling and aligning table 4.

The object to be measured 9 is leveled by the lever table, the lever of the lever is brought into contact with the top of the object to be measured 9, the air float table 3 is rotated, the tilt of the cylindrical surface is adjusted by the leveling workpiece table 4, and finally the cylindrical surface is rotated. In one week, the readings of the lever table vary on the order of micrometers.

The object to be measured 9 is aligned by the laser measuring system 8, and the target probe 808 is placed at any height within the cylindrical surface 9 to be tested by controlling the X-direction translational movement of the two-dimensional motion table 5 and the movement in the Z direction, and The target probe 8 is spaced apart from the surface of the cylindrical surface to be tested by a predetermined distance, preferably about 0.6 mm, and the air float table 3 is rotated again, and the eccentricity of the cylindrical surface to be tested is adjusted by the leveling and aligning workpiece table 4 The cylindrical surface to be tested is rotated one revolution, and the amount of change of the distance between the target probe 808 and the measured cylindrical surface is on the order of micrometers.

Considering the measurement results of the lever table and the laser measuring system 8, the inclination and eccentricity of the cylindrical surface are repeatedly adjusted, and finally the cylindrical surface is rotated one revolution, and the measurement results of the lever table and the laser measuring system 8 are all less than a threshold value, generally 1 m. At this point, it can be considered that the axis of the cylindrical surface coincides with the axis of rotation.

Step B: obtaining an ideal shape;

The geometric parameters of the measured surface are input into the computer 12 one by one. Taking a cylindrical shape as an example, the geometric parameters include the topmost height Z0 of the cylindrical surface, the radius of curvature R0 of the cylindrical surface, the length of the busbar of the cylindrical surface, etc., and the data processing device of the computer 12 is based on the These geometric parameters calculate the ideal shape.

Step C: scanning and sampling the measured surface of the object 9 to be measured by using the laser measuring system 8;

The control box 11 issues an instruction to make the target probe 808 of the laser measuring system 8 perpendicular to the cylindrical surface, and scans from the top of the cylindrical surface, and descends uniformly along the direction of the busbar of the cylindrical surface until the target probe moves to the bottom of the cylindrical surface, while The air floating turntable 3 is rotated at a constant speed, and the cylindrical surface is rotated and scanned until the entire cylindrical surface is scanned to obtain measurement data of a plurality of sampling points, the measurement data including the rotation time of the turntable, the measured surface and the target probe 808 The absolute distance, the X-direction displacement amount and the Z-direction displacement amount of the target probe 808 when measuring the sampling point. During the scanning process, the computer 12 determines the approximate shape of the measured surface based on the pre-input parameters of the measured surface, and controls the target probe 808 to be separated from the measured surface by a predetermined distance. The distance from the target probe 808 to the measured surface needs to be greater than the target probe. The focal length of 808 is easy to be disturbed by dust particles and surface flaws at the focus of the target probe 808. The design of the focal length can improve the ability of the target probe 808 to resist environmental interference. In the present embodiment, the predetermined distance is preferably about 0.6. Mm. The turntable 3 is always rotated at a constant rate during scanning, which is determined by the sampling interval.

Step D: obtaining a measured surface shape;

The data processing device of the computer 12 calculates the data of the measured cylindrical surface based on the measurement data of the plurality of sampling points obtained by the laser measuring system 8.

Step E: obtaining a surface shape error of the measured surface;

The comparison module of the computer 12 compares the ideal surface shape and the measured surface shape to obtain a surface shape error of the measured surface.

In the present invention, in order to achieve high-precision measurement, X-direction and Z in the two-dimensional motion table 5 can also be performed. Calibration of the straightness error of the moving mechanism, calibration of the angle between the Z-direction reference probe and the rotating shaft, calibration of the X-direction reference probe and the perpendicularity of the rotating shaft, and the eccentricity and perpendicularity calibration of the optical axis of the target measuring head relative to the rotating shaft, etc. The error in the measurement.

In the present invention, the optical measuring sensor is susceptible to environmental temperature, humidity, pressure, and airflow disturbance. The change in temperature, humidity, and pressure changes the refractive index of the air, and the airflow disturbance causes uneven distribution of the refractive index of the air. Therefore, in addition to strict control of the temperature, humidity and pressure of the measurement environment, temperature, humidity and barometric pressure sensors can be added to facilitate real-time compensation of environmental parameters, and a protective cover is added to the peripheral surface of the measurement system to reduce airflow disturbance. Impact.

It should be noted that the shapes and sizes of the various components in the drawings do not reflect the true size and proportions, but merely illustrate the contents of the embodiments of the present invention.

The directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are merely referring to the directions of the drawings, and are not intended to limit the invention. protected range. The above embodiments may be used in combination with other embodiments or based on design and reliability considerations, that is, the technical features in different embodiments may be freely combined to form more embodiments.

It should be noted that the implementations that are not shown or described in the drawings or the text of the specification are all known to those of ordinary skill in the art and are not described in detail. In addition, the above definitions of the various elements and methods are not limited to the specific structures, shapes or manners mentioned in the embodiments, and those skilled in the art can simply modify or replace them, for example:

(1) It is not necessary to level the centering table 4, and it is known that the object to be tested 9 is directly placed on the turntable 3 for adjustment to avoid tilting and eccentricity;

(2) The laser 800 is not necessarily disposed in the control box 11, and may be disposed at other positions, such as the side plate 101. At this time, the optical fiber or the optical waveguide is used to transmit the laser light emitted by the laser 800 to the first beam splitter 801;

(3) Replace the cantilever 6 and the extension rod 7 with an integrally formed L-shaped fixing rod to reduce the assembly.

The specific embodiments of the present invention have been described in detail in the foregoing detailed description of the embodiments of the present invention. All modifications, equivalents, improvements, etc., made within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

A measuring device for rotating axisymmetrical surface shape error, comprising:

Base (1);

a turntable (3) is disposed on the base (1) for driving the object to be tested (9) to rotate around the rotating shaft;

a laser measuring system (8) for scanning and sampling the measured surface of the measured object (9) during the rotation of the measured object (9) to obtain a plurality of sampling point data;

The computing device calculates a surface shape error based on the geometric parameters of the measured surface and the plurality of sampling point data.
The measuring device of claim 1 wherein said computing device comprises:

The data processing module calculates an ideal surface shape based on the input geometric parameters of the measured surface, and calculates a measured surface shape based on the plurality of sampling point data;

Comparing the module, comparing the ideal surface shape with the measured surface shape, and determining and outputting the surface shape error.
The measuring device according to claim 1, characterized in that the laser measuring system (8) comprises:

a laser (800) for emitting a laser for measurement;

a light splitting device disposed at a rear end of the optical path of the laser for dividing the laser into a first laser, a second laser, and a third laser;

a target measuring module, configured to measure an absolute distance D between itself and the measured surface based on the first laser;

An X-direction measurement module, configured to measure an X-direction displacement amount Dx of the target measurement module based on the second laser;

a Z-direction measurement module, configured to measure a Z-direction displacement amount Dz of the target measurement module based on the third laser;

Wherein, the X direction is a horizontal direction and the Z direction is a vertical direction, and each sampling point data includes the absolute distance D measured at the point, the X-direction displacement amount Dx, and the Z-direction displacement amount Dz.
The measuring device according to claim 3, wherein the measuring device further comprises: a control device;

Wherein, when the measured surface is a cylindrical surface, the control device controls the rotation of the control turntable (3), and controls the target measurement module of the laser measurement system (8) from the top of the cylindrical surface along the direction of the busbar of the cylindrical surface The sampling is completed by dropping to the bottom of the cylindrical surface at a constant speed.
The measuring device according to claim 4, characterized in that

The base (1) includes: a vibration isolation table (102) and a side plate (101) disposed perpendicular to the vibration isolation table (102) and located at one end side of the vibration isolation table (102);

The measuring device further includes:

a frame (2), erected above the base (1), comprising: a beam (201) and two brackets (202) supporting the beam;

a two-dimensional moving table (5) mounted on the side plate (101), perpendicular to the upper surface of the turntable (3), capable of moving in the X direction and/or the Z direction;

a cantilever (6) is disposed parallel to the upper surface of the turntable (3), and the first end (601) of the cantilever (6) is fixed to the two-dimensional motion table (5), and the second end of the cantilever (6) 602) located above the turntable (3);

The extension rod (7) is disposed parallel to the Z direction, the first end (701) of the extension rod (7) is fixed to the second end (602) of the cantilever (6), and the second end of the extension rod (7) (702) ) is suspended above the turntable (3) and directed to the upper surface of the turntable (3).
The measuring device according to claim 5, characterized in that

The spectroscopic device includes:

a first beam splitter (801), a second beam splitter (802), and a first mirror (803) are sequentially arranged on the cantilever (6) in a Z-direction from bottom to top, the first beam splitter (801) Receiving the laser, emitting a first laser along the length of the cantilever (6), and a second laser and a third laser to the second beam splitter (802) along the Z direction, the second beam splitter (802) along the cantilever ( 6) emitting a second laser in the longitudinal direction, and emitting a third laser in the Z direction upward to the first mirror (803), and the third laser is emitted along the length of the cantilever (6) via the first mirror (803);

The laser measurement system (8) further includes:

a second mirror (806) for reflecting the third laser;

a Z-mirror (811) disposed at a bottom of the beam (201) opposite to the Z-direction measuring module;

An X-ray mirror (812) disposed on an inner side of one of the brackets (202), and the X Relatively set to the measurement module;

The second mirror (806), the Z-direction measuring module and the X-direction measuring module are arranged in the Z direction from bottom to top on the first end (701) of the cantilever (6) extension rod (7), respectively The first beam splitter (801), the second beam splitter (802), and the first mirror (803) are correspondingly received, respectively receiving the first laser, the second laser, and the third laser;

The target measurement module is disposed on the second end (702) of the extension rod (7) and receives the third laser light reflected by the second mirror (806).
The measuring device according to claim 6, wherein the target measuring module is rotatable by 180 in a horizontal direction.
The measuring device according to claim 6, wherein the measuring device further comprises:

Leveling the centering table (4), fixed to the top of the turntable (3);

The object to be measured is fixed on the leveling and aligning table (4), and the leveling and aligning of the object to be tested (9) is realized by the leveling and aligning table (4);

The frame (2), the turntable (3) and the leveling and aligning table (4) are coaxial, in the Z direction.
The measuring device according to claim 3, wherein the target measuring module comprises:

Target measurement interferometer (807);

a target probe (808) located in the direction of measurement of the target measurement interferometer (807);

Wherein, the target probe (808) is a converging lens, the converging lens has a diameter of less than 10 mm, a focal length of less than 500 μm, and an NA greater than 0.5.
The measuring device according to claim 10, characterized in that:

The Z-direction measurement module includes: a Z-direction displacement interferometer (804) and a Z-directed reference probe (809) located in a measurement direction of the Z-direction displacement interferometer (804);

The X-direction measurement module includes: an X-direction displacement interferometer (805) and an X-directed reference probe (810) located in a measurement direction of the X-direction displacement interferometer (805);

The Z-direction displacement interferometer (804), the X-direction displacement interferometer (805), and the target measurement interferometer (807) are less than 10 mm x 10 mm x 10 mm in size.
The measuring device according to claim 11, wherein said laser (800) is a multi-wavelength laser, and said measuring laser is a multi-wavelength laser;

The target measurement interferometer (807), the Z-direction displacement interferometer (804), and the X-direction displacement interferometer (805) are all interferometers based on the principle of multi-wavelength interference.
The measuring device according to claim 6, characterized in that the base (1) further comprises a vibration isolating leg (103) for supporting the vibration isolating table (102).
A measuring device for a rotational axisymmetric curved surface shape error, comprising the measuring device according to any one of claims 1 to 12, comprising:

Step A: The computing device obtains an ideal shape based on the geometric parameters of the measured surface;

Step B: The control device controls the rotation of the turntable (3) in the measuring device, and controls the laser measuring system (8) to scan and sample the measured surface to obtain measurement data of each sampling point;

Step C: The computing device obtains the measured surface shape based on the measurement data of the sampling point;

Step D: The computing device obtains a face shape error based on the ideal face shape and the measured face shape.
The measuring method according to claim 13, wherein:

The measuring device further comprises: a leveling and aligning workbench (4), which is arranged on the turntable (3);

Before the step A, the method further includes:

Step A': placing the object to be measured (9) on the leveling and aligning table (4) for leveling and aligning.
The measuring method according to claim 13, wherein

The step A includes the data processing module of the computing device receiving the geometric parameters of the measured surface, and calculating an ideal surface shape based on the geometric parameters.
The measuring method according to claim 13, wherein

The step C includes: the data processing module of the computing device receives the measurement data of each sampling point, and calculates a measured surface shape based on the measurement data of the sampling points.
The measuring method according to claim 13, wherein

The step D includes: the comparison module of the computing device receives the ideal surface shape and the measured surface shape, and compares the measured surface shape with the ideal surface shape to obtain a surface shape error.
The measuring method according to claim 13, wherein the measured surface is a cylindrical surface,

The scanning sampling in the step B is: controlling the rotation of the turntable (3), and the target measuring module of the control laser measuring system (8) is uniformly descended from the top of the cylindrical surface to the bottom of the cylindrical surface along the direction of the busbar of the cylindrical surface. .