Rotary table rotating shaft and calibration method of encoder of rotary table rotating shaft

Abstract

The invention discloses a calibration method for a rotary table rotating shaft and an encoder of the rotary table rotating shaft, and belongs to the technical field of precise instruments. According to the method, the accuracy of any angle point, the axial runout and the deflection pitching vibration angle of the rotary table encoder in the whole period are calibrated at the same time, additional instruments and devices do not need to be added, and therefore the accuracy of the encoder assembled on a high-precision rotary table and the whole-period calibration of the posture of a rotary shaft are achieved; the necessary technical foundation is made for improving the precision and the stability of the turntable, and the operation is convenient.

Description

Technical Field

[0001] This application relates to the field of precision instruments, and particularly to a calibration method for a turntable rotating shaft and its encoder. Background Art

[0002] High-precision turntables are not only the core technical carriers in the field of precision engineering. Their development will directly boost the leap of key industries such as semiconductors, aerospace, and biomedicine, and provide basic support for scenarios such as smart factories and future laboratories, with profound value. The resolution accuracy of the encoder of the turntable and the resolution accuracy of the runout and vibration interference of the rotating shaft during the rotation process after assembly always affect the rotation accuracy of the turntable. Therefore, it is necessary to calibrate the turntable with the encoder already assembled. Currently, the commonly used calibration method for turntable encoders is the metrological technical specification: JJF1115-2004, which uses a calibration method combining a multi-face prism and an autocollimator. This method measures points at equal interval angles to verify the error of circular grating encoding, and calibrates the encoder error within the interval angle as a value. Therefore, this method is not a calibration verification for any angle point within the full period of the circular grating in a strict sense. Moreover, if you also want to obtain the shaft diameter runout and yaw and pitch vibration angles of the rotating shaft, additional instrument transpositions are required, so the operability is not very good. Summary of the Invention

[0003] This application aims to address the above problems and propose a method that can achieve the calibration of the accuracy of any angle point within the full period of the turntable encoder, as well as the shaft diameter runout and yaw and pitch vibration angles of the rotating shaft simultaneously.

[0004] To achieve the above objective, the technical solution of this application is as follows: A calibration method for a turntable rotating shaft and its encoder, including: Using an objective lens, a charge-coupled image sensor, a cylindrical lens, and a fluorescence excitation light source to form a fluorescence microscope with an astigmatic imaging function and a fixed spatial position; Fixing three fluorescence microspheres on a flat substrate so that the three fluorescence microspheres are imaged on the charge-coupled image sensor; Determining a longitudinal object plane of the fluorescence microscope and the normal vector of a longitudinal object plane according to the XY-axis width ratio obtained from the imaging of each fluorescence microsphere; Obtaining the microscopic magnification function of each fluorescence microsphere according to the functional relationship between the longitudinal object plane height function and the XY-axis width ratio of each fluorescence microsphere; Starting the turntable to be calibrated to ensure that each fluorescence microsphere can be imaged on the charge-coupled image sensor during one full rotation of the turntable rotating shaft; The spatial plane coordinate values of each fluorescent microsphere mapped to the imaging plane coordinates of the charge-coupled image sensor are obtained according to the microscopic magnification function and the imaging centroid coordinates of each fluorescent microsphere, and plane ellipse function fitting is performed to determine that the rotation axis of the turntable is parallel to the imaging optical axis of the fluorescence microscope. At the starting moment of the turntable rotation axis, the spatial three-dimensional coordinate values of each fluorescent microsphere are obtained according to the spatial plane coordinate values of each fluorescent microsphere and the function values of their respective longitudinal object plane heights, and the included angle between the substrate plane and the X-axis of the spatial coordinate system of the fluorescent microsphere and the included angle between the substrate plane and the Y-axis of the spatial coordinate system of the fluorescent microsphere are obtained. When the turntable rotation axis rotates, calibration data of the turntable encoder accuracy within a complete rotation period is obtained according to the fitted ellipse and the angle values of each turntable rotation axis rotation step angle encoder; radial runout data within a complete rotation period of the turntable rotation axis is obtained according to the spatial plane coordinate values of each fluorescent microsphere and the center of the fitted ellipse; axial runout data within a complete rotation period of the turntable rotation axis is obtained according to the spatial three-dimensional coordinate values of each fluorescent microsphere; calibration data of the yaw and pitch vibration angles within a complete rotation period is obtained according to the included angle between the substrate plane and the X-axis and the included angle between the substrate plane and the Y-axis.

[0005] Optionally, the fluorescence microscope with astigmatic imaging function having a fixed spatial position is composed of an objective lens, a charge-coupled image sensor, a cylindrical lens, and a fluorescence excitation light source, including: placing the cylindrical lens between the objective lens and the charge-coupled image sensor, the bottom surface of the cylindrical lens is parallel to the charge-coupled image sensor, and the edge where the semi-circular cross-section of the cylindrical lens intersects the bottom surface of the cylindrical lens is parallel to the X-axis direction of the imaging surface of the charge-coupled image sensor, the normal vector of the charge-coupled image sensor is parallel to the imaging optical axis of the objective lens, a fluorescence excitation light source is sleeved outside the objective lens, and after the fluorescence excitation light source is turned on, the excitation light beam is incident on the spatial area under the objective lens; the objective lens, the charge-coupled image sensor, the cylindrical lens, and the fluorescence excitation light source constitute a fluorescence microscope with astigmatic imaging function having a fixed spatial position.

[0006] Optionally, the three fluorescent microspheres are fixed on a flat substrate, and the three fluorescent microspheres are imaged on a charge-coupled image sensor, including: fixing the three fluorescent microspheres on a flat substrate, the three fluorescent microspheres being distributed in a triangle, the spacing distances between the three fluorescent microspheres being unequal and all in the millimeter range, where the fluorescent microsphere corresponding to the intersection point of the longest spacing distance segment and the second-longest spacing distance segment is denoted as the first fluorescent microsphere, the fluorescent microsphere corresponding to the intersection point of the longest spacing distance segment and the shortest spacing distance segment is denoted as the second fluorescent microsphere, and the fluorescent microsphere corresponding to the intersection point of the second-longest spacing distance segment and the shortest spacing distance segment is denoted as the third fluorescent microsphere; fixing the substrate parallel on a six-dimensional calibration displacement stage, placing the six-dimensional calibration displacement stage with the substrate under a fluorescence microscope, and after turning on the fluorescence excitation light source, irradiating the three fluorescent microspheres, so that the three fluorescent microspheres emit fluorescence, and the three fluorescent microspheres are imaged on the charge-coupled image sensor.

[0007] Optionally, obtaining the XY-axis width ratio of each fluorescent microsphere according to the imaging of each fluorescent microsphere, and determining a longitudinal object plane of the fluorescence microscope and the normal vector of a longitudinal object plane, including: respectively fitting the imaging of the three fluorescent microspheres through a two-dimensional Gaussian function to obtain the centroid position of the imaging of each of the three fluorescent microspheres and the width values of the imaging light intensity distribution of each spot along the X-axis and Y-axis directions of the imaging surface of the charge-coupled image sensor, and obtaining the XY-axis width ratio of each; making the six-dimensional calibration displacement stage perform two translational motions with non-parallel motion directions, selecting a fluorescent microsphere, and obtaining the three XY-axis width ratios corresponding to the three images of the selected fluorescent microsphere before and after motion on the charge-coupled image sensor. If the three XY-axis width ratios are the same, it indicates that the plane determined by the two translational motion directions is a longitudinal object plane of the fluorescence microscope; traversing the pitch and yaw postures of the six-dimensional calibration displacement stage with the smallest step size, and performing the above translational motion in each posture case, obtaining the three XY-axis width ratios corresponding to the selected fluorescent microsphere, and finding the posture vector of the six-dimensional calibration displacement stage when the three XY-axis width ratios are the same ( m , n , q ) as the vector value in the self-motion coordinate system of the six-dimensional calibration displacement stage, and this vector value is the normal vector of a determined longitudinal object plane.

[0008] Optionally, obtaining the microscopic magnification function of each fluorescent microsphere according to the functional relationship between the longitudinal object plane height function and the XY-axis width ratio of each fluorescent microsphere, including: making the six-dimensional calibration displacement stage move along the posture vector ( m , n , q)(Move back and forth in a direction), and image the first fluorescent microsphere, the second fluorescent microsphere, and the third fluorescent microsphere to obtain the functional relationship between the different longitudinal object plane heights of each fluorescent microsphere relative to the longitudinal object plane of the focal point and the ratio of the imaging XY-axis width of the fluorescent microsphere, and obtain the longitudinal object plane height function of each fluorescent microsphere; translate a displacement value on the six-dimensional calibration displacement stage on each longitudinal object plane, obtain the displacement measurement value of each fluorescent microsphere on the charge-coupled image sensor, and divide the displacement measurement value of each fluorescent microsphere by the displacement value of the six-dimensional calibration displacement stage to obtain the microscopic magnification value on each longitudinal object plane.

[0009] Optionally, starting the calibrated turntable to ensure that each fluorescent microsphere can be imaged on the charge-coupled image sensor during one rotation of the turntable axis includes: fixing the fluorescence microscope on a six-dimensional adjustment displacement stage, fixing the substrate with three fluorescent microspheres on the micro-adjustment stage, and fixing the micro-adjustment stage on the turntable axis of the calibrated turntable; starting the calibrated turntable to rotate the turntable axis one circle to ensure that all three fluorescent microspheres can be imaged by the fluorescence microscope during one rotation of the turntable axis. If a fluorescent microsphere fails to be imaged, adjust the micro-adjustment stage until all fluorescent microspheres can be imaged.

[0010] Optionally, obtaining the spatial plane coordinate values of each fluorescent microsphere mapped to the imaging plane coordinates of the charge-coupled image sensor according to the microscopic magnification function and the imaging centroid coordinates of each fluorescent microsphere, and performing plane ellipse function fitting to determine that the rotation axis of the turntable is parallel to the imaging optical axis of the fluorescence microscope, includes: After determining that all fluorescent microspheres can be imaged, restart the calibrated turntable again, so that the turntable rotation axis of the calibrated turntable rotates a minimum step angle and then stops moving, record the imaging of each fluorescent microsphere by the fluorescence microscope, obtain the imaging centroid coordinates and the imaging XY-axis width ratio of each fluorescent microsphere in the imaging plane coordinates of the charge-coupled image sensor by fitting the imaging light intensity with a two-dimensional Gaussian function, find the microscopic magnification function value corresponding to the longitudinal object plane height where each fluorescent microsphere is located through the imaging XY-axis width ratio of each fluorescent microsphere, and divide the imaging centroid coordinates by the microscopic magnification function value to obtain the spatial plane coordinate values of each fluorescent microsphere mapped to the imaging plane coordinates of the charge-coupled image sensor; Select a fluorescent microsphere, after the turntable rotation axis rotates one circle, a series of different spatial plane coordinate values of this selected fluorescent microsphere are obtained, and these data are used for plane ellipse function fitting with a general ellipse function whose major and minor axes of the ellipse are not parallel to the coordinate axes. This fitted ellipse is the spatial trajectory of the plane drawn by the fluorescent microsphere when the turntable rotation axis rotates. Record the length values of the major and minor axes of the fitted ellipse at this time, traverse the pitch and yaw postures of the six-dimensional adjustment displacement stage with the smallest step, and perform a full rotation cycle of the turntable rotation at each posture. Thus, a length value of the major and minor axes of the fitted ellipse can be obtained at each posture. When the major axis and the minor axis of the fitted ellipse corresponding to a posture are both the minimum values in all traversed postures, that is, when the rotation axis is perpendicular to the imaging plane of the charge-coupled image sensor, the length of the spatial plane trajectory of the mapped imaging is the shortest. At this time, the rotation axis of the turntable is parallel to the imaging optical axis of the fluorescence microscope.

[0011] Optionally, at the starting moment of the turntable rotation axis, obtaining the spatial three-dimensional coordinate values of each fluorescent microsphere according to the spatial plane coordinate values of each fluorescent microsphere and their respective longitudinal object plane height function values, and obtaining the angle between the substrate plane and the X-axis of the spatial coordinate system of the fluorescent microsphere and the angle between the substrate plane and the Y-axis of the spatial coordinate system of the fluorescent microsphere, includes: After determining that the rotation axis is parallel to the imaging optical axis of the fluorescence microscope, restart the calibrated turntable to make the turntable rotation axis rotate one circle, and stop moving after rotating each minimum step angle, and record the imaging data of the fluorescence microscope; The angular position of the turntable rotation axis at the starting moment is recorded as the starting position. By adding the spatial plane coordinate values on the imaging plane of the three charge-coupled image sensors obtained, and the longitudinal object plane height function values of the three fluorescent microspheres respectively, the spatial three-dimensional coordinate values of each fluorescent microsphere are obtained. Through the spatial three-dimensional coordinate values of the three fluorescent microspheres, the spatial distances of the three fluorescent microspheres are obtained, thereby determining the first fluorescent microsphere, the second fluorescent microsphere, and the third fluorescent microsphere; The spatial three-dimensional coordinates of the three fluorescent microspheres are respectively recorded as ( xA启 , y A启 , z A启 ), ( x B启 , y B启 , z B启 ), and ( x C启 , y C启 , z C启 ); From the three-dimensional spatial coordinates of these three fluorescent microspheres, obtain the spatial coordinates of the foot of the perpendicular from the third fluorescent microsphere to the spatial line determined by the first and second fluorescent microspheres, and denote the spatial coordinates of the foot of the perpendicular as ( x N启 , y N启 , z N启 ), expressed as follows: ; The spatial line determined by the first and second fluorescent microspheres α AB启 , and the spatial line determined by the third fluorescent microsphere and the foot of the perpendicular ( x N启 , y N启 , z N启 ), respectively, the angles formed with the Y-axis in the YZ-plane of the fluorescent microsphere spatial coordinate system are expressed as: α CN启 ; The spatial line determined by the first and second fluorescent microspheres β AB启 , and the spatial line determined by the third fluorescent microsphere and the foot of the perpendicular ( x N启 , y N启 , z N启 ), respectively, the angles formed with the X-axis in the XZ-plane of the fluorescent microsphere spatial coordinate system are expressed as: β CN启 .

[0012] Optionally, in the fluorescence microsphere spatial coordinate system, when the rotary table rotation axis is in the starting position, the angle between the substrate plane with three fluorescence microspheres and the X-axis represents the initial yaw angle ; the angle between the substrate plane with three fluorescence microspheres and the Y-axis represents the initial pitch angle .

[0013] Optionally, the calibration data of the rotary table encoder accuracy within a complete rotation period obtained according to the fitted ellipse and the angle values of each rotary table rotation axis rotation step angle encoder includes: the rotary table rotation axis rotates one circle with a minimum step angle, and a series of three-dimensional space coordinates of each fluorescence microsphere in the fluorescence microsphere spatial coordinate system at each rotary table rotation step angle are respectively recorded. The series of three-dimensional space coordinates of each fluorescence microsphere are respectively uniformly marked as ( x A , y A , z A ), ( x B , y B , z B ), and ( x C , y C , z C ); the XY-axis plane coordinates of the series of three fluorescence microspheres ( x A , y A ), ( x B , y B ), and ( x C , y C ) are respectively subjected to plane ellipse function fitting, and the fitted ellipse with the largest major axis and its corresponding fluorescence microsphere are selected. The central plane coordinates of the fitted ellipse are obtained as ( x o , y o ), and the angle x o , y o between the connection line from any coordinate point on the selected fitted ellipse function to the ellipse center ( θ , denoted as θ 启 at the starting position; the angle value of the encoder at each rotary table rotation step angle is denoted as δ, record the angular value of the encoder at the starting position as δ 启 , ( θ - θ 启 ) and ( δ - δ 启 ) the difference represents the calibration data of the turntable encoder accuracy within a complete rotation period; The radial runout data of the turntable shaft within a complete rotation period obtained according to the spatial plane coordinate values of each fluorescent microsphere and the center of the fitted ellipse includes: the distance from the XY-axis plane coordinates of the selected fluorescent microsphere corresponding to each rotation step angle of the turntable shaft to ( x o , y o ), and the difference between the distance from the coordinate point on the selected fitted ellipse function corresponding to this angle to the center of the ellipse ( x o , y o ) represents the radial runout data of the turntable shaft within a complete rotation period; The axial runout data of the turntable shaft within a complete rotation period obtained according to the spatial three-dimensional coordinate values of each fluorescent microsphere includes: z A - z A启 or z B - z B启 or z C - z C启 represents all the axial runout data corresponding to each rotation step angle of the turntable shaft within a complete rotation period; The calibration data of the yaw and pitch vibration angles within a complete rotation period obtained according to the angle between the substrate plane and the X-axis and the angle between the substrate plane and the Y-axis includes: the yaw angle and the pitch angle , and respectively represent the calibration data of the yaw and pitch vibration angles within a complete rotation period, where, α AB represents the spatial straight line determined by the first fluorescent microsphere and the second fluorescent microsphere corresponding to each rotation step angle of the turntable shaft, α CN represents the third fluorescent microsphere and the foot of the perpendicular corresponding to each rotation step angle of the turntable shaft ( x N , yN , z N ), the spatial straight line determined β AB represents the spatial straight line determined by the first fluorescent microsphere and the second fluorescent microsphere corresponding to the rotation step angle of each turntable rotating shaft β CN represents the third fluorescent microsphere and the foot of the perpendicular corresponding to the rotation step angle of each turntable rotating shaft ( x N , y N , z N ), the spatial straight line determined

[0014] This application realizes a method that can calibrate the accuracy, axial diameter jump, and yaw and pitch vibration angles at any angle point within the full cycle of the turntable encoder simultaneously without adding additional instrument devices, thereby realizing the full-cycle calibration of the accuracy of the encoder assembled on the high-precision turntable and the attitude of the rotating shaft, making necessary technical preparations for improving the accuracy and stability of the turntable, and being convenient to operate.

[0015] To make the above features and advantages of the application more obvious and understandable, specific embodiments are hereinafter given and described in detail in conjunction with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a three-dimensional measurement and calibration schematic diagram of the calibration device for the turntable rotating shaft and its encoder.

[0017] Figure 2 It is a schematic diagram of the substrate 10 fixed with three fluorescent microspheres fixed on a six-dimensional precision calibration displacement stage 11.

[0018] Figure 3 It is a schematic diagram of detecting and calibrating the turntable rotating shaft and its encoder to be calibrated using a fluorescence microscope.

[0019] Figure 4 It is a flowchart of a calibration method for a turntable rotating shaft and its encoder provided by this application.

[0020] In the drawings: 1 objective lens, 2 cylindrical lens, 3 charge-coupled image sensor, 4 imaging optical axis, 5 fluorescence excitation light source, 6 fluorescence microscope, 7 fluorescent microsphere, 8 fluorescent microsphere, 9 fluorescent microsphere, 10 substrate, 11 six-dimensional precision calibration displacement stage, 12 focal longitudinal object plane, 13 turntable to be calibrated, 14 turntable rotating shaft, 15 rotation axis, 16 six-dimensional precision adjustment displacement stage, 17 micro adjustment stage.

[0021] In the accompanying drawings, similar reference numerals refer to the same drawing elements. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] To make the objectives and technical solutions of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions of the embodiments of this application with reference to the accompanying drawings of the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of this application without creative work fall within the scope of protection of this application.

[0023] The following further describes the specific embodiments of the present invention in detail with reference to the accompanying drawings.

[0024] A calibration method for a turntable rotating shaft and its encoder provided by this application is used to detect and calibrate the turntable rotating shaft to be calibrated and its encoder.

[0025] Please refer to Figure 1 , Figure 1 FIG. is a three-dimensional measurement calibration schematic diagram of a calibration device for a turntable rotating shaft and its encoder. A cylindrical lens 2 is placed between an objective lens 1 and a charge-coupled image sensor (CCD) 3. The bottom surface of the cylindrical lens 2 is parallel to the charge-coupled image sensor 3. The edge where the semi-circular cross-section of the cylindrical lens 2 intersects the bottom surface of the cylindrical lens 2 is parallel to the X-axis direction of the imaging surface of the charge-coupled image sensor 3. The normal vector of the charge-coupled image sensor 3 is parallel to the imaging optical axis of the objective lens 1. An annular fluorescence excitation light source 5 is sleeved outside the objective lens 1; the objective lens 1, the charge-coupled image sensor 3, the cylindrical lens 2, and the fluorescence excitation light source 5 form a fluorescence microscope 6 with an astigmatic imaging function and fixed spatial positions; three sub-millimeter-scale fluorescence microspheres are fixed on a flat substrate 10. These three fluorescence microspheres are distributed in a triangular shape, and the spacing distances between these three fluorescence microspheres are not equal, and the spacing distances are all in the millimeter range.

[0026] As an example, among the three fluorescence microspheres, the fluorescence microsphere corresponding to the intersection point of the longest spacing distance segment and the second-longest spacing distance segment is denoted as fluorescence microsphere 7, the fluorescence microsphere corresponding to the intersection point of the longest spacing distance segment and the shortest spacing distance segment is denoted as fluorescence microsphere 8, and the fluorescence microsphere corresponding to the intersection point of the second-longest spacing distance segment and the shortest spacing distance segment is denoted as fluorescence microsphere 9.

[0027] As an example, the substrate 10 can be fixed on a six-dimensional calibration displacement stage. The six-dimensional calibration displacement stage includes: a six-dimensional precision calibration displacement stage 11; please refer to Figure 2 , Figure 2 FIG. is a schematic diagram of the substrate 10 fixed with three fluorescence microspheres fixed on a six-dimensional precision calibration displacement stage 11.

[0028] Please continue to refer to Figure 3 , Figure 3 FIG. is a schematic diagram of using a fluorescence microscope to detect and calibrate the turntable rotating shaft to be calibrated and its encoder.

[0029] As an example, the substrate 10 can also be fixed on a micro-adjustment stage 17, and the micro-adjustment stage 17 is fixed on the turntable shaft 14 of the calibrated turntable 13. As an example, please refer to Figure 4 , Figure 4 which is a flowchart of a calibration method for a turntable shaft and its encoder provided by the present application. The calibration method for a turntable shaft and its encoder provided by the present application includes steps S1 to S8: Step S1: Use an objective lens 1, a charge-coupled image sensor 3, a cylindrical lens 2, and a fluorescence excitation light source 5 to form a fluorescence microscope 6 with an astigmatic imaging function and a fixed spatial position.

[0030] Step S2: Fix three sub-millimeter-sized fluorescent microspheres on a flat substrate 10 so that the three fluorescent microspheres are imaged on the charge-coupled image sensor.

[0031] Step S3: Determine a longitudinal object plane of the fluorescence microscope 6 and the normal vector of a longitudinal object plane according to the XY-axis width ratio obtained from the imaging of each fluorescent microsphere.

[0032] Step S4: Obtain the microscopic magnification function of each fluorescent microsphere according to the functional relationship between the longitudinal object plane height function and the XY-axis width ratio of each fluorescent microsphere.

[0033] Step S5: Start the calibrated turntable 13 to ensure that each fluorescent microsphere can be imaged on the charge-coupled image sensor during one rotation of the turntable shaft 14.

[0034] Step S6: According to the microscopic magnification function and the imaging centroid coordinates of each fluorescent microsphere, obtain the spatial plane coordinate values of each fluorescent microsphere mapped to the imaging plane coordinates of the charge-coupled image sensor 3, and perform plane ellipse function fitting to determine that the rotation axis of the calibrated turntable 13 is parallel to the imaging optical axis 4 of the fluorescence microscope 6.

[0035] Step S7: At the starting moment of the turntable shaft 14, obtain the spatial three-dimensional coordinate values of each fluorescent microsphere according to the spatial plane coordinate values and the respective longitudinal object plane height function values of each fluorescent microsphere, and obtain the angle between the plane of the substrate 10 and the X-axis of the spatial coordinate system of the fluorescent microsphere and the angle between the plane of the substrate 10 and the Y-axis of the spatial coordinate system of the fluorescent microsphere.

[0036] Step S8: When the turntable rotating shaft 14 rotates, calibration data of the turntable encoder accuracy within a complete rotation period is obtained based on the fitted ellipse and the angular values of the stepping angle encoder for each rotation of the turntable rotating shaft 14; radial runout data of the turntable rotating shaft 14 within a complete rotation period is obtained based on the spatial plane coordinate values of each fluorescent microsphere and the center of the fitted ellipse; axial runout data of the turntable rotating shaft 14 within a complete rotation period is obtained based on the spatial three-dimensional coordinate values of each fluorescent microsphere; calibration data of the yaw and pitch vibration angles within a complete rotation period is obtained based on the angle between the substrate 10 plane and the X-axis and the angle between the substrate 10 plane and the Y-axis.

[0037] As an example, step S1 specifically includes: placing the cylindrical lens 2 between the objective lens 1 and the charge-coupled image sensor 3. The bottom surface of the cylindrical lens 2 is parallel to the charge-coupled image sensor 3, and the edge where the semi-circular cross-section of the cylindrical lens 2 intersects with the bottom surface of the cylindrical lens 2 is parallel to the X-axis direction of the imaging surface of the charge-coupled image sensor 3. The normal vector of the charge-coupled image sensor 3 is parallel to the imaging optical axis 4 of the objective lens 1. An annular fluorescent excitation light source 5 is sleeved outside the objective lens 1. After the fluorescent excitation light source 5 is turned on, the excitation light beam can be incident on the spatial region under the objective lens 1. The objective lens 1, the charge-coupled image sensor 3, the cylindrical lens 2, and the fluorescent excitation light source 5 form a fluorescence microscope 6 with an astigmatic imaging function and fixed spatial positions.

[0038] As an example, step S2 specifically includes: fixing three sub-millimeter fluorescent microspheres on a flat substrate 10. These three fluorescent microspheres are distributed in a triangle, and the spacing distances between the three fluorescent microspheres are not equal, and all the spacing distances are of the order of millimeters. The fluorescent microsphere corresponding to the intersection point of the longest spacing distance segment and the second-longest spacing distance segment is denoted as the fluorescent microsphere 7. The fluorescent microsphere corresponding to the intersection point of the longest spacing distance segment and the shortest spacing distance segment is denoted as the fluorescent microsphere 8. The fluorescent microsphere corresponding to the intersection point of the second-longest spacing distance segment and the shortest spacing distance segment is denoted as the fluorescent microsphere 9. Then, the substrate 10 is fixedly mounted on a six-dimensional precision calibration displacement stage 11 in parallel. The six-dimensional precision calibration displacement stage 11 with the substrate 10 is placed under the fluorescence microscope 6. After the fluorescent excitation light source 5 is turned on, it irradiates the three fluorescent microspheres, causing them to emit fluorescence, so that the three fluorescent microspheres can be imaged on the charge-coupled image sensor 3.

[0039] As an example, step S3 specifically includes: The imaging of the three fluorescent microspheres is respectively fitted by a two-dimensional Gaussian function. In addition to obtaining the centroid positions of the images of the three fluorescent microspheres, the width values of the light intensity distributions of their respective spot images along the X-axis and Y-axis directions of the imaging plane of the charge-coupled image sensor 3 can also be obtained, and then the XY-axis width ratios of each can be obtained, that is, the width ratios in the X-axis and Y-axis directions; on different longitudinal object planes, that is, the imaging object planes perpendicular to the imaging optical axis 4, the width ratios in the X-axis and Y-axis directions due to the astigmatic imaging of the cylindrical lens 2 are different. Make the six-dimensional precision calibration displacement stage 11 perform translational motions in two non-parallel directions. Select a fluorescent microsphere and obtain the three XY-axis width ratios corresponding to the three images before and after the movement of this fluorescent microsphere on the charge-coupled image sensor 3. If these three XY-axis width ratios are the same, it means that the plane determined by these two translational motion directions is a longitudinal object plane of the fluorescence microscope 6. Traverse the pitch and yaw postures of the six-dimensional precision calibration displacement stage 11 with the smallest step size. In each posture case, perform the above translational motion and obtain the three XY-axis width ratios corresponding to the selected fluorescent microsphere, and find the posture vector of the six-dimensional precision calibration displacement stage 11 when the three XY-axis width ratios are the same ( m , n , q ). As the vector value in the self-motion coordinate system of the six-dimensional precision calibration displacement stage 11, this vector value is the normal vector of a determined longitudinal object plane and is also the vector of the imaging optical axis 4.

[0040] As an example, step S4 specifically includes: Make the six-dimensional precision calibration displacement stage 11 move back and forth along the direction of the posture vector ( m , n , q ), and make the fluorescent microspheres 7, 8, and 9 all have imaging. The functional relationships between the different longitudinal object plane heights of each fluorescent microsphere relative to the longitudinal object plane 12 of the relative focus and the imaging XY-axis width ratio of this fluorescent microsphere can be obtained. Denote these three longitudinal object plane height functions as f A ( w A ), f B ( w B ), and f C ( w C ), where w A , w B , and w Care the XY axis width ratios of fluorescent microsphere 7, fluorescent microsphere 8 and fluorescent microsphere 9 respectively. Further, on each longitudinal object plane, the six-dimensional precision calibration displacement stage 11 is translated by a displacement value, and the displacement measurement value of each fluorescent microsphere is obtained on the charge coupled image sensor 3. The displacement measurement value of each fluorescent microsphere is divided by the displacement value of the six-dimensional precision calibration displacement stage 11 to obtain the microscopic magnification value on each longitudinal object plane. The microscopic magnification value is different for different longitudinal object plane heights. The microscopic magnification value is a function value related to the longitudinal object plane height or the XY axis width ratio of the fluorescent microsphere imaging; the microscopic magnification functions of the three fluorescent microspheres are respectively recorded as N A ( w A ), N B ( w B )and N C ( w C ). As an example, step S5 specifically includes: fixing the fluorescence microscope 6 on a six-dimensional adjustment displacement stage, the six-dimensional adjustment displacement stage includes: a six-dimensional precision adjustment displacement stage 16; then fixing the substrate 10 with three fluorescent microspheres on the micro-adjustment stage 17, and then fixing the micro-adjustment stage 17 on the turntable shaft 14 of the calibrated turntable 13. Start the calibrated turntable 13 to rotate the turntable shaft 14 one circle, ensuring that the three fluorescent microspheres can be imaged by the fluorescence microscope 6 during the rotation of the turntable shaft 14. If there are fluorescent microspheres that are not imaged, it is necessary to adjust the micro-adjustment stage 17 until all fluorescent microspheres can be imaged.

[0041] As an example, step S6 specifically includes: after determining that all fluorescent microspheres can be imaged, the calibrated turntable 13 is started again, so that the turntable shaft 14 of the calibrated turntable 13 rotates by a minimum step angle and then stops moving. Then, the fluorescence microscope 6 records the imaging of each fluorescent microsphere. The centroid coordinates of the imaging of each fluorescent microsphere and the ratio of the imaging XY-axis width in the imaging plane coordinates of the charge-coupled image sensor 3 are obtained by fitting the imaging light intensity with a two-dimensional Gaussian function. The microscopic magnification function value corresponding to the longitudinal object plane height where each fluorescent microsphere is located can be found through the ratio of the imaging XY-axis width of each fluorescent microsphere. Divide the imaging centroid coordinates by the microscopic magnification function value to obtain the spatial plane coordinate values of each fluorescent microsphere mapped to the imaging plane coordinates of the charge-coupled image sensor 3. Select a fluorescent microsphere. After the turntable shaft 14 rotates one circle, a series of different spatial plane coordinate values of this selected fluorescent microsphere can be obtained. These data are fitted with a general elliptic function with the major and minor axes of the ellipse not parallel to the coordinate axes. The fitted ellipse is the spatial trajectory of the plane drawn by the fluorescent microsphere when the turntable shaft 14 rotates. Record the length values of the major and minor axes of the fitted ellipse at this time. Traverse the pitch and yaw postures of the six-dimensional precision adjustment displacement stage 16 with the minimum step size. A complete rotation cycle of the turntable is performed at each posture. Thus, a length value of the major and minor axes of the fitted ellipse can be obtained at each posture. When the major axis and minor axis of the fitted ellipse corresponding to a posture are the minimum values in all traversed postures, that is, when the rotation axis 15 is perpendicular to the imaging plane of the charge-coupled image sensor 3, the length of the spatial plane trajectory of the mapped imaging is the shortest. At this time, the turntable rotation axis 15 is parallel to the imaging optical axis 4 of the fluorescence microscope 6; As an example, step S7 specifically includes: after determining that the rotation axis 15 is parallel to the imaging optical axis 4 of the fluorescence microscope 6, the calibrated turntable 13 is started again to make the turntable shaft 14 rotate one circle. After each rotation of a minimum step angle, it stops moving, and the imaging data of the fluorescence microscope 6 are recorded. The angular position of the turntable shaft 14 at the start-up moment is recorded as the starting position. Since the spatial coordinate system where the three fluorescent microspheres are located is a coordinate system obtained by translating the spatial coordinate system determined by the charge-coupled image sensor 3 along the imaging optical axis 4 to the focal longitudinal object plane 12, that is, the spatial plane coordinate values on the imaging plane of the charge-coupled image sensor 3 are equal to the spatial plane coordinate values on the XY-axis plane of the spatial coordinate system of the fluorescent microsphere. By obtaining the three spatial plane coordinate values on the imaging plane of the charge-coupled image sensor 3, plus the longitudinal object plane height function values of the three fluorescent microspheres respectively, the spatial three-dimensional coordinate values of each fluorescent microsphere are obtained. Through the spatial three-dimensional coordinate values of these three fluorescent microspheres, the spatial distances between these three fluorescent microspheres can be obtained, so as to determine the fluorescent microsphere 7, the fluorescent microsphere 8, and the fluorescent microsphere 9. At this time, the spatial three-dimensional coordinates of these three fluorescent microspheres are respectively recorded as ( x A启 , yA启 , z A启 ), ( x B启 , y B启 , z B启 ), and ( x C启 , y C启 , z C启 ), in addition, from the three-dimensional spatial coordinates of these three fluorescent microspheres, the spatial coordinates of the foot of the perpendicular from fluorescent microsphere 9 to the spatial line determined by fluorescent microspheres 7 and 8 can be obtained, and the coordinates of this foot of the perpendicular are denoted as ( x N启 , y N启 , z N启 ), expressed as follows: Specifically, the spatial line α AB启 , determined by fluorescent microspheres 7 and 8, and the spatial line x N启 , y N启 , z N启 ), determined by fluorescent microsphere 9 and the foot of the perpendicular ( α CN启 , are respectively expressed as the angles with the Y-axis in the YZ-plane of the fluorescent microsphere spatial coordinate system as: Specifically, the spatial line β AB启 , determined by fluorescent microspheres 7 and 8, and the spatial line x N启 , y N启 , z N启 ), determined by fluorescent microsphere 9 and the foot of the perpendicular ( β CN启 , are respectively expressed as the angles with the X-axis in the XZ-plane of the fluorescent microsphere spatial coordinate system as: From this, in the fluorescent microsphere spatial coordinate system, when the turntable rotation axis 14 is in the starting position, the angle between the plane of the substrate 10 with three fluorescent microspheres and the X-axis, that is, the initial yaw angle, is ; the angle between the plane of the substrate 10 with three fluorescent microspheres and the Y-axis, i.e., the initial pitch angle is .

[0042] As an example, step S8 specifically includes: the turntable rotating shaft 14 rotates one circle with a minimum step angle, and a series of three-dimensional space coordinates of each fluorescent microsphere in the spatial coordinate system of the fluorescent microsphere are respectively recorded at each step angle of the rotation of the turntable rotating shaft. The series of three-dimensional space coordinates of each fluorescent microsphere are respectively uniformly marked as ( x A , y A , z A ), ( x B , y B , z B ), and ( x C , y C , z C ). The XY-axis plane coordinates of the series of three fluorescent microspheres ( x A , y A ), ( x B , y B ), and ( x C , y C ) are respectively subjected to plane elliptic function fitting, and the fitting ellipse with the largest major axis and its corresponding fluorescent microsphere are selected. The central plane coordinates of the fitting ellipse are obtained as ( x o , y o ), and the angle x o , y o between the connection line of any coordinate point on the selected fitting ellipse function to the ellipse center ( θ , and the major axis of the ellipse is recorded. The angle at the starting position is recorded as θ 启 . The angle value of the encoder when each turntable rotating shaft 14 rotates the step angle is recorded as δ , and the angle value of the encoder at the starting position is recorded as δ 启 , ( θ - θ 启 ) and ( δ - δ启 ) The difference is the calibration data of the turntable encoder accuracy within a complete rotation period. The XY-axis plane coordinates of the selected fluorescent microspheres corresponding to each rotation step angle of the turntable shaft 14 to ( x o , y o ) The distance, and the difference between the coordinates of the selected fitting ellipse function corresponding to this angle to the center of the ellipse ( x o , y o ) The distance forms the radial runout data of the turntable shaft 14 within a complete rotation period. z A - z A启 Or z B - z B启 Or z C - z C启 Is all the axial runout data corresponding to each rotation step angle of the turntable shaft 14 within a complete rotation period. Similar to step S7, the yaw angle And the pitch angle , And Are the calibration data of the yaw and pitch vibration angles within a complete rotation period. Among them, α AB Represents the space line determined by the fluorescent microspheres 7 and 8 corresponding to each rotation step angle of the turntable shaft 14, α CN Represents the space line determined by the fluorescent microsphere 9 and the foot of the perpendicular ( x N , y N , z N ) Determined space line, β AB Represents the space line determined by the fluorescent microspheres 7 and 8 corresponding to each rotation step angle of the turntable shaft 14, β CN Represents the space line determined by the fluorescent microsphere 9 and the foot of the perpendicular ( x N , y N , z N ) Determined space line.

[0043] The present application realizes a method that can simultaneously calibrate the accuracy at any angular point within the full cycle of a turntable encoder, the shaft diameter jump, and the yaw and pitch vibration angles, without adding additional instrument devices, thereby realizing the full-cycle calibration of the encoder accuracy and the shaft attitude assembled on a high-precision turntable, making necessary technical preparations for improving the accuracy and stability of the turntable, and being convenient to operate.

[0044] Although the present application has been disclosed as above by way of embodiments, it is not intended to limit the present application. Any person with ordinary knowledge in the technical field to which the present application pertains may make some modifications and refinements without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application shall be subject to that defined by the appended patent application scope.

Claims

1. A calibration method for a turntable rotating shaft and its encoder, characterized in that, including, using an objective lens, a charge-coupled image sensor, a cylindrical lens, and a fluorescence excitation light source to form a fluorescence microscope with an astigmatic imaging function and a fixed spatial position; fixing three fluorescence microspheres on a planar substrate so that the three fluorescence microspheres are imaged on the charge-coupled image sensor; obtaining the XY-axis width ratio of each fluorescence microsphere according to the imaging of each fluorescence microsphere, and determining a longitudinal object plane of the fluorescence microscope and the normal vector of a longitudinal object plane; obtaining the microscopic magnification function of each fluorescence microsphere according to the functional relationship between the longitudinal object plane height function of each fluorescence microsphere and the XY-axis width ratio; starting the calibrated turntable to ensure that each fluorescence microsphere can be imaged on the charge-coupled image sensor during one rotation of the turntable rotation axis; obtaining the spatial plane coordinate values of each fluorescence microsphere mapped to the imaging plane coordinates of the charge-coupled image sensor according to the microscopic magnification function of each fluorescence microsphere and the imaging centroid coordinates, and performing planar ellipse function fitting to determine that the turntable rotation axis is parallel to the imaging optical axis of the fluorescence microscope; at the starting moment of the turntable rotation axis, obtaining the spatial three-dimensional coordinate values of each fluorescence microsphere according to the spatial plane coordinate values of each fluorescence microsphere and the respective longitudinal object plane height function values, and obtaining the angle between the substrate plane and the X-axis of the spatial coordinate system of the fluorescence microsphere and the angle between the substrate plane and the Y-axis of the spatial coordinate system of the fluorescence microsphere; when the turntable rotation axis rotates, obtaining the calibration data of the turntable encoder accuracy within a complete rotation period according to the fitted ellipse and the angle values of each turntable rotation axis rotation step angle encoder; obtaining the radial runout data of the turntable rotation axis within a complete rotation period according to the spatial plane coordinate values of each fluorescence microsphere and the center of the fitted ellipse; obtaining the axial runout data of the turntable rotation axis within a complete rotation period according to the spatial three-dimensional coordinate values of each fluorescence microsphere; obtaining the calibration data of the yaw and pitch vibration angles within a complete rotation period according to the angle between the substrate plane and the X-axis and the angle between the substrate plane and the Y-axis.

2. The calibration method of the turntable rotating shaft and its encoder according to claim 1, characterized in that, The fluorescence microscope with an astigmatic imaging function and a fixed spatial position formed by using an objective lens, a charge-coupled image sensor, a cylindrical lens, and a fluorescence excitation light source includes: placing the cylindrical lens between the objective lens and the charge-coupled image sensor, the bottom surface of the cylindrical lens being parallel to the charge-coupled image sensor, and the edge where the semi-circular cross-section of the cylindrical lens intersects the bottom surface of the cylindrical lens being parallel to the X-axis direction of the imaging surface of the charge-coupled image sensor, the normal vector of the charge-coupled image sensor being parallel to the imaging optical axis of the objective lens, and a fluorescence excitation light source being sleeved outside the objective lens. After the fluorescence excitation light source is turned on, the excitation light beam is incident on the spatial area under the objective lens; the objective lens, the charge-coupled image sensor, the cylindrical lens, and the fluorescence excitation light source form a fluorescence microscope with an astigmatic imaging function and a fixed spatial position.

3. The calibration method of the rotary table shaft and its encoder according to claim 2, characterized in that, The three fluorescent microspheres are fixed on a planar substrate, and the three fluorescent microspheres are imaged on a charge-coupled image sensor, including: fixing the three fluorescent microspheres on a planar substrate, the three fluorescent microspheres are distributed in a triangle, the spacing distances between the three fluorescent microspheres are not equal, and the spacing distances are all on the order of millimeters. The fluorescent microsphere corresponding to the intersection point of the longest spacing distance segment and the second-longest spacing distance segment is denoted as the first fluorescent microsphere, the fluorescent microsphere corresponding to the intersection point of the longest spacing distance segment and the shortest spacing distance segment is denoted as the second fluorescent microsphere, and the fluorescent microsphere corresponding to the intersection point of the second-longest spacing distance segment and the shortest spacing distance segment is denoted as the third fluorescent microsphere; the substrate is fixedly placed on a six-dimensional calibration displacement stage, and the six-dimensional calibration displacement stage with the substrate is placed under a fluorescence microscope. After turning on the fluorescence excitation light source, it irradiates the three fluorescent microspheres, so that the three fluorescent microspheres emit fluorescence, and the three fluorescent microspheres are imaged on the charge-coupled image sensor.

4. The calibration method of the rotary table shaft and its encoder according to claim 3, characterized in that, The method of determining a longitudinal object plane and the normal vector of a longitudinal object plane of a fluorescence microscope according to the XY-axis width ratio obtained from the imaging of each fluorescence microsphere includes: fitting the images of three fluorescence microspheres through a two-dimensional Gaussian function respectively, obtaining the centroid positions of the images of the three fluorescence microspheres and the width values of the imaging light intensity distributions of their respective light spots along the X-axis and Y-axis directions of the imaging surface of the charge-coupled image sensor, and obtaining the XY-axis width ratios of each; making the six-dimensional calibration displacement stage perform two translational motions with non-parallel directions, selecting a fluorescence microsphere, and obtaining three XY-axis width ratios corresponding to three images of the fluorescence microsphere before and after movement on the charge-coupled image sensor. If these three XY-axis width ratios are the same, it indicates that the plane determined by these two translational motion directions is a longitudinal object plane of the fluorescence microscope; traversing the pitch and yaw postures of the six-dimensional calibration displacement stage with the smallest step size, and performing the above translational motion in each posture case, obtaining the three XY-axis width ratios corresponding to the selected fluorescence microsphere, and finding the posture vector ( m , n , q ) of the six-dimensional calibration displacement stage in its own moving coordinate system when the three XY-axis width ratios are the same. This vector value is the normal vector of a determined longitudinal object plane.

5. The calibration method of the turntable rotating shaft and its encoder according to claim 4, characterized in that, The microscopic magnification function of each fluorescent microsphere obtained according to the functional relationship between the longitudinal object plane height function and the XY-axis width ratio of each fluorescent microsphere includes: making the six-dimensional calibration displacement stage move back and forth along the attitude vector ( m , n , q ), and imaging the first fluorescent microsphere, the second fluorescent microsphere, and the third fluorescent microsphere to obtain the functional relationship between the different longitudinal object plane heights of each fluorescent microsphere relative to the longitudinal object plane of the focus and the XY-axis width ratio of the imaging of the fluorescent microsphere, and obtaining the longitudinal object plane height function of each fluorescent microsphere; translating the six-dimensional calibration displacement stage by a displacement value on each longitudinal object plane, obtaining the displacement measurement value of each fluorescent microsphere on the charge-coupled image sensor, and dividing the displacement measurement value of each fluorescent microsphere by the displacement value of the six-dimensional calibration displacement stage to obtain the microscopic magnification value on each longitudinal object plane.

6. The calibration method of the turntable rotating shaft and its encoder according to claim 5, characterized in that, Start the calibrated turntable to ensure that each fluorescent microsphere can be imaged on the charge-coupled image sensor during one rotation of the turntable rotation axis, including: fixing the fluorescence microscope on a six-dimensional adjustment displacement stage, fixing the substrate with the three fluorescent microspheres on a micro-adjustment stage, and fixing the micro-adjustment stage on the turntable rotation axis of the calibrated turntable; start the calibrated turntable to make the turntable rotation axis rotate one circle, and ensure that the three fluorescent microspheres can be imaged by the fluorescence microscope during one rotation of the turntable rotation axis. If a fluorescent microsphere fails to be imaged, adjust the micro-adjustment stage until all fluorescent microspheres can be imaged.

7. The calibration method of the turntable rotating shaft and its encoder according to claim 6, characterized in that, The spatial plane coordinate values of each fluorescent microsphere mapped to the imaging plane coordinates of the charge-coupled image sensor are obtained according to the microscopic magnification function and the imaging centroid coordinates of each fluorescent microsphere, and the plane ellipse function fitting is performed to determine that the rotation axis of the turntable is parallel to the imaging optical axis of the fluorescence microscope, including: after determining that all fluorescent microspheres can be imaged, restart the calibrated turntable again, so that the turntable axis of the calibrated turntable rotates by a minimum step angle and then stops moving, record the imaging of each fluorescent microsphere by the fluorescence microscope, obtain the imaging centroid coordinates and the imaging XY-axis width ratio of each fluorescent microsphere in the imaging plane coordinates of the charge-coupled image sensor through two-dimensional Gaussian function fitting of the imaging light intensity, find the microscopic magnification function value corresponding to the longitudinal object plane height where each fluorescent microsphere is located through the imaging XY-axis width ratio of each fluorescent microsphere, and divide the imaging centroid coordinates by the microscopic magnification function value to obtain the spatial plane coordinate values of each fluorescent microsphere mapped to the imaging plane coordinates of the charge-coupled image sensor; select a fluorescent microsphere, after the turntable axis rotates one circle, a series of different spatial plane coordinate values of this selected fluorescent microsphere are obtained, and these data are used for plane ellipse function fitting with a general ellipse function whose major and minor axes of the ellipse are not parallel to the coordinate axes. This fitted ellipse is the spatial trajectory of the plane mapped by the fluorescent microsphere when the turntable axis rotates, record the length values of the major and minor axes of the fitted ellipse at this time, traverse the pitch and yaw postures of the six-dimensional adjustment displacement stage with the minimum step size, and perform a complete rotation cycle of the turntable rotation at each posture, so that a length value of the major and minor axes of the fitted ellipse can be obtained at each posture. When the major axis and the minor axis of the fitted ellipse corresponding to a posture are the minimum values in all traversed postures, that is, when the rotation axis is perpendicular to the imaging plane of the charge-coupled image sensor, the length of the spatial plane trajectory of the mapped imaging is the shortest, and at this time the rotation axis of the turntable is parallel to the imaging optical axis of the fluorescence microscope.

8. The calibration method of the turntable rotating shaft and its encoder according to claim 7, characterized in that, At the starting moment of the turntable rotating shaft, the three-dimensional spatial coordinate values of each fluorescent microsphere are obtained according to the spatial plane coordinate values and the respective longitudinal object plane height function values of each fluorescent microsphere, and the included angles between the substrate plane and the X-axis of the spatial coordinate system of the fluorescent microspheres and between the substrate plane and the Y-axis of the spatial coordinate system of the fluorescent microspheres are obtained, including: after determining that the rotation axis is parallel to the imaging optical axis of the fluorescence microscope, the calibrated turntable is started again to rotate the turntable rotating shaft for one circle. After each rotation of a minimum step angle, it stops moving, and the imaging data of the fluorescence microscope are recorded; the angular position of the turntable rotating shaft at the starting moment is recorded as the starting position. By adding the spatial plane coordinate values on the imaging surfaces of the three charge-coupled image sensors obtained, plus the longitudinal object plane height function values of the three fluorescent microspheres respectively, the three-dimensional spatial coordinate values of each fluorescent microsphere are obtained. Through the three-dimensional spatial coordinate values of the three fluorescent microspheres, the spatial distances between the three fluorescent microspheres are obtained, so as to determine the first fluorescent microsphere, the second fluorescent microsphere and the third fluorescent microsphere; the three-dimensional spatial coordinates of the three fluorescent microspheres are respectively recorded as ( x A启 , y A启 , z A启 ), ( x B启 , y B启 , z B启 ), and ( x C启 , y C启 , z C启 ); from the three-dimensional spatial coordinates of these three fluorescent microspheres, the spatial coordinates of the foot of the perpendicular from the third fluorescent microsphere to the spatial straight line determined by the first fluorescent microsphere and the second fluorescent microsphere are obtained, and the spatial coordinates of the foot of the perpendicular are recorded as ( x N启 , y N启 , z N启 ), which is expressed as follows: ； The spatial straight line determined by the first fluorescent microsphere and the second fluorescent microsphere α AB启 , and the spatial straight line determined by the third fluorescent microsphere and the foot of the perpendicular ( x N启 , y N启 , z N启 ), are respectively expressed as the angles with the Y-axis on the YZ-axis plane of the fluorescent microsphere spatial coordinate system: α CN启 ​ ； The spatial straight line determined by the first fluorescent microsphere and the second fluorescent microsphere β AB启 , and the spatial straight line determined by the third fluorescent microsphere and the foot of the perpendicular ( x N启 , y N启 , z N启 ), respectively, the angles with the X-axis on the XZ-axis plane of the fluorescent microsphere space coordinate system are expressed as: β CN启 ​ 。 9. The calibration method of the turntable rotating shaft and its encoder according to claim 8, characterized in that, In the spatial coordinate system of the fluorescent microspheres, when the turntable rotation axis is at the starting position, the angle between the substrate plane with three fluorescent microspheres and the X-axis represents the initial yaw angle ; The angle between the substrate plane with three fluorescent microspheres and the Y-axis represents the initial pitch angle .

10. The calibration method of the rotary table shaft and its encoder according to claim 9, characterized in that, The calibration data of the turntable encoder accuracy within a complete rotation period obtained according to the fitted ellipse and the angle values of each turntable rotation axis rotation step angle encoder include: the turntable rotation axis rotates one circle with a minimum step angle, and a series of three-dimensional space coordinates of each fluorescent microsphere in the spatial coordinate system of the fluorescent microsphere at each turntable rotation axis rotation step angle are respectively recorded. The series of three-dimensional space coordinates of each fluorescent microsphere are respectively uniformly marked as ( x A , y A , z A ), ( x B , y B , z B ), and ( x C , y C , z C ); The XY-axis plane coordinates of the series of three fluorescent microspheres ( x A , y A ), ( x B , y B ), and ( x C , y C ) are respectively subjected to plane ellipse function fitting, and the fitted ellipse with the largest major axis and its corresponding fluorescent microsphere are selected. The central plane coordinates of the fitted ellipse are obtained as ( x o , y o ), and the angle x o , y o between the connection line of any coordinate point on the selected fitted ellipse function to the ellipse center ( θ , θ 启 ); The angle value of the encoder at each turntable rotation axis rotation step angle is recorded as δ , and the angle value of the encoder at the starting position is recorded as δ 启 , ( θ - θ 启 ) and ( δ - δ 启 ) The difference represents the calibration data of the turntable encoder accuracy within a complete rotation period; The radial runout data within a complete rotation period of the turntable rotation axis obtained based on the spatial plane coordinate values of each fluorescence microsphere and the center of the fitted ellipse includes: the distances from the XY-plane coordinates of the selected fluorescence microspheres corresponding to each rotation step angle of the turntable rotation axis to ( x o , y o ), and the differences between the distances from the coordinate points on the selected fitted ellipse function corresponding to this angle to the center of the ellipse ( x o , y o ), representing the radial runout data within a complete rotation period of the turntable rotation axis; Obtaining the axial runout data within a complete rotation period of the turntable rotation axis based on the three-dimensional spatial coordinate values of each fluorescent microsphere, including: z A - z A启 or z B - z B启 or z C - z C启 indicating that all the axial runout data within a complete rotation period correspond to each rotation step angle of the turntable rotation axis; The calibration data of the yaw and pitch vibration angles within a complete rotation period obtained according to the angle between the substrate plane and the X-axis and the angle between the substrate plane and the Y-axis includes: the yaw angle corresponding to the rotation step angle of each turntable shaft and the pitch angle , and respectively represent the calibration data of the yaw and pitch vibration angles within a complete rotation period. Among them, α AB represents the space straight line determined by the first fluorescent microsphere and the second fluorescent microsphere corresponding to the rotation step angle of each turntable shaft, α CN represents the space straight line determined by the third fluorescent microsphere and the foot of the perpendicular ( x N , y N , z N ) corresponding to the rotation step angle of each turntable shaft, β AB represents the space straight line determined by the first fluorescent microsphere and the second fluorescent microsphere corresponding to the rotation step angle of each turntable shaft, β CN represents the space straight line determined by the third fluorescent microsphere and the foot of the perpendicular ( x N , y N , z N ) corresponding to the rotation step angle of each turntable shaft.

Images