Method and device for detecting errors of rotary table and rotary shaft of overall measurement light path connection upper rotary shaft type laser tracker

Abstract

The invention discloses a method and a device for detecting errors of a rotary table and a rotary shaft of an overall measurement light path connected upper rotary shaft type laser tracker, and belongs to the technical field of laser tracking measurement. The device comprises a microscope, a fluorescent microsphere, a substrate and a six-dimensional precision calibration displacement table, the microscope is located above the fluorescent microsphere, and the six-dimensional precision calibration displacement table is located above the substrate. The fluorescent microspheres are fixed on the substrate, and the substrate is fixed on the six-dimensional precise calibration displacement table. By combining the fluorescence microscope with the astigmatism imaging function, the precise displacement table, space coordinate calculation and other operations, the determination of the axis space linear equation of the upper and lower rotary tables of the whole measurement light path connected upper rotary shaft type laser tracker and the detection of the shaft radial runout in a complete rotation period are realized under one coordinate system; a necessary technical foundation is laid for realizing error compensation of the rotary table and the rotary shaft of the rotary shaft type laser tracker connected with an overall measurement light path and improving the tracking precision and the stability of the laser tracker.

Description

Technical Field

[0001] The present invention relates to the technical field of laser tracking measurement, and particularly to a method and device for detecting the rotational shaft errors of the turntable of an upper rotational shaft type laser tracker in connection with an overall measurement optical path. Background Art

[0002] Laser trackers are characterized by high speed, high precision, and large measurement range, and have extensive applications in fields such as aerospace, automotive manufacturing, electronics industry, and large-scale metrology. Currently, the overall measurement optical path of many laser trackers on the market serves as the middle section of the upper turntable rotational shaft, connecting the rotational shafts on the motor side and the encoder side of the upper turntable, thereby realizing the servo pitching rotation of the upper turntable.

[0003] The turntable of a laser tracker includes an upper pitching rotary turntable and a lower horizontal rotary table. The two turntables respectively correspond to the pitching axis and the horizontal rotation axis. Ideally, the two rotation axes are perfectly perpendicular to each other in space (without distance deviation), and there is no axial and radial runout when the two rotational shafts rotate. However, in reality, the perpendicularity of the two rotation axes is not perfectly 90°, and they do not intersect ideally in space (with a distance deviation), and there is shaft diameter runout during rotation. These non-ideal error conditions will affect the tracking accuracy and stability of the laser tracker. Therefore, it is necessary to detect and calibrate these two rotational shaft-related errors to provide a prerequisite for realizing the error compensation of the two rotational shafts.

[0004] The detection of the perpendicularity and distance deviation of the two rotational shafts of a laser tracker can be attributed to the determination of the spatial straight line equations of the two rotational shaft axes. Therefore, the rotational shaft error detection includes the determination of the spatial straight line equations of the rotational axes and the detection of their shaft diameter runout. Currently, the techniques and methods for separately detecting the perpendicularity and shaft diameter runout of the two rotational shafts of a laser tracker are relatively common, but there is no article or technical data presenting a method for determining the spatial straight line equations of the axes in a single coordinate system and simultaneously detecting the shaft diameter runout. For the upper rotational shaft type laser tracker turntable with an overall measurement optical path connection, since its upper rotational shaft is divided into the motor side and the encoder side, in addition to detecting the spatial straight line equation of the lower turntable axis and the shaft diameter runout, it is also necessary to detect the spatial straight line equations of the two parts of the upper turntable rotational shafts and the shaft diameter runout. Currently, there is no article or literature presenting a method for determining the three spatial straight line equations of the axes of this upper rotational shaft type laser tracker turntable with an overall measurement optical path connection and simultaneously detecting the shaft diameter runout. Summary of the Invention

[0005] In view of the above problems, the present invention proposes a method and device for detecting the rotational shaft errors of the turntable of an upper rotational shaft type laser tracker in connection with an overall measurement optical path, so as to realize the determination of the spatial straight line equations of the three rotational axes and the simultaneous detection of the shaft diameter runout.

[0006] In a first aspect, the present application provides a method for detecting the shaft error of the turntable of an upper rotating shaft type laser tracker in connection with an overall measurement optical path, comprising the following steps: Step S1: Construct a microscope using an objective lens, a cylindrical lens, a charge-coupled image sensor, a standard 45-degree beam-splitting cube mirror block, and a fluorescence excitation light source; Step S2: Set up the microscope, fluorescence microspheres, substrate, and six-axis precision calibration displacement stage so that the fluorescence microspheres are imaged on the charge-coupled image sensor; Step S3: Make the six-axis precision calibration displacement stage perform translational motions in two non-parallel directions of motion, obtain the ratio of the widths of three XY axes corresponding to three images of the fluorescence microspheres before and after motion on the charge-coupled image sensor, and determine the attitude vector of the six-axis precision calibration displacement stage when the ratios of the widths of the three XY axes are the same before and after motion; Step S4: Make the six-axis precision calibration displacement stage move back and forth along the direction of the attitude vector and ensure that the fluorescence microspheres can be imaged on the charge-coupled image sensor, obtain the functional relationship between the height of the longitudinal object plane and the ratio of the widths of the XY axes of the fluorescence microspheres, that is, the longitudinal object plane height function; on each longitudinal object plane, translate the six-axis precision calibration displacement stage by an actual displacement value, determine the measured displacement value of the corresponding fluorescence microspheres imaged on the charge-coupled image sensor, and obtain the microscopic magnification function according to the actual displacement value and the measured displacement value; Step S5: Fix the first gear and the second gear on the first shaft and the second shaft of the upper turntable respectively, and fix a bracket with a gear transmission shaft on one side on the tabletop of the lower turntable; Step S6: Fix the microscope on a six-axis precision adjustment displacement stage, fix the substrate with fluorescence microspheres on the tabletop of a micro translation adjustment stage, and fix the micro translation adjustment stage on the upper turntable, the first shaft, the second shaft, and the lower turntable shaft in sequence; Step S7: Fix the micro translation adjustment stage with fluorescence microspheres and substrate on the lower turntable shaft, start the lower turntable motor, make the lower turntable shaft rotate by a minimum step angle and then stop, record the image of the fluorescence microspheres by the microscope, determine the centroid coordinates and the ratio of the widths of the XY axes in the imaging plane coordinates of the charge-coupled image sensor through a two-dimensional Gaussian function, determine the microscopic magnification corresponding to the height of the longitudinal object plane where the fluorescence microspheres are located according to the ratio of the widths of the XY axes, and determine the spatial coordinate values of the fluorescence microspheres mapped to the imaging plane coordinates of the charge-coupled image sensor according to the centroid coordinates and the microscopic magnification; Step S8: Construct a first reference coordinate system according to the spatial coordinate values, determine the spatial straight line equation of the rotation axis of the lower turntable in the first reference coordinate system, and obtain the radial runout value within a complete rotation period of the lower turntable shaft; Step S9: Set the rotating shaft of the lower turntable stationary, record the spatial coordinate values of the fluorescent microspheres in the first reference coordinate system, construct the motion coordinate system of the six-dimensional precision adjustment displacement stage, determine the first vector value of the unit vector on the X-axis of the motion coordinate system in the first reference coordinate system, determine the first coordinate value of the origin of the motion coordinate system in the first reference coordinate system, rotate the six-dimensional precision adjustment displacement stage by a first angle around the X-axis of the motion coordinate system, and rotate the unit vector in the first reference coordinate system by the first angle around the first vector value to obtain a second vector value; Step S10: Rotate the first reference coordinate system by the first angle around the X-axis of the motion coordinate system to obtain the measurement coordinate system of the microscope, determine the spatial coordinate values of the fluorescent microspheres in the measurement coordinate system, and obtain the spatial coordinate relationship of the fluorescent microspheres before and after the six-dimensional precision adjustment displacement stage rotates by the first angle; Step S11: Rotate the six-dimensional precision adjustment displacement stage back to the starting posture, determine the third vector value of the unit vector on the Y-axis of the motion coordinate system of the six-dimensional precision adjustment displacement stage in the first reference coordinate system, rotate the six-dimensional precision adjustment displacement stage by a second angle around the Y-axis of the motion coordinate system, obtain the spatial coordinate relationship of the fluorescent microspheres before and after the six-dimensional precision adjustment displacement stage rotates by the second angle, and obtain the first vector value, the first coordinate value, and the third vector value through the least squares method; Step S12: Fix the micro translation adjustment stage with the fluorescent microspheres and the substrate on the first rotating shaft of the upper turntable, start the motor of the upper turntable to control the rotation of the first rotating shaft, construct the second reference coordinate system, determine the spatial straight line equation of the rotation axis on the motor side of the upper turntable in the second reference coordinate system, and obtain the axial and radial runout values within a complete rotation period; Step S13: Determine the yaw angle and pitch angle of the second reference coordinate system relative to the first reference coordinate system according to the six-dimensional precision adjustment displacement stage, rotate the unit vector in the first reference coordinate system by the yaw angle and pitch angle to obtain the spatial coordinate values of the fluorescent microspheres in the second reference coordinate system in the first reference coordinate system, and convert the spatial straight line equation of the rotation axis of the upper turntable into the spatial straight line equation in the first coordinate system; Step S14: Fix the micro translation adjustment stage with the fluorescent microspheres and the substrate on the second rotating shaft of the upper turntable, and start the motor of the lower turntable to rotate 180 degrees to symmetrically interchange the positions of the encoder side and the motor side of the upper turntable, obtain the axial and radial runout values within a complete rotation period, determine the spatial straight line equations of the rotation axis of the lower turntable and the rotation axis of the encoder side of the upper turntable in the first reference coordinate system, and realize the determination of the spatial straight line equations of the rotation axis of the lower turntable, the rotation axis on the motor side of the upper turntable, and the rotation axis of the encoder side of the upper turntable in the same reference coordinate system and the error detection within a complete rotation period.

[0007] Optionally, a microscope is constructed using an objective lens, a cylindrical lens, a charge-coupled image sensor, a standard 45-degree beam-splitting cube, and a fluorescence excitation light source, including: Place 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 is parallel to the X-axis of the imaging plane of the charge-coupled image sensor. The normal vector of the imaging plane of the charge-coupled image sensor is parallel to the imaging optical axis of the objective lens. Place a standard 45-degree beam-splitting cube under the objective lens. The standard 45-degree beam-splitting cube includes a beam-splitting surface. The edge of the beam-splitting surface is parallel to the X-axis of the imaging plane of the charge-coupled image sensor. After the fluorescence beam passes through the beam-splitting surface, it enters the objective lens, passes through the cylindrical lens, and is received by the charge-coupled image sensor. Place the fluorescence excitation light source on the mirror side at an angle of 45 degrees to the beam-splitting surface. The objective lens, the charge-coupled image sensor, the cylindrical lens, the standard 45-degree beam-splitting cube, and the fluorescence excitation light source form a microscope. The coordinate value of the intersection point of the imaging optical axis of the objective lens and the imaging plane of the charge-coupled image sensor in the plane coordinate system of its imaging plane is ( x o , y o ), and the imaging optical axis of the objective lens passes through the center point of the beam-splitting surface of the standard 45-degree beam-splitting cube. The distance between the focal longitudinal object plane of the microscope and the center point of the beam-splitting surface is D.

[0008] Optionally, set up a microscope, a fluorescent microsphere, a substrate, and a six-axis precision calibration displacement stage to image the fluorescent microsphere on the charge-coupled image sensor, including: Fix a fluorescent microsphere on a substrate, and then fix the substrate parallel on a six-axis precision calibration displacement stage. Place the six-axis precision calibration displacement stage with the substrate at the lower end of the beam incident surface at the bottom of the standard 45-degree beam-splitting cube under the microscope. After turning on the fluorescence excitation light source, the light beam of the light source is reflected by the standard 45-degree beam-splitting cube and irradiates the fluorescent microsphere, causing the fluorescent microsphere to emit fluorescence. After passing through the standard 45-degree beam-splitting cube, the fluorescent microsphere is imaged on the charge-coupled image sensor.

[0009] Optionally, make the six-axis precision calibration displacement stage perform two translational motions with non-parallel directions of motion, obtain the ratios of the widths of the three XY axes corresponding to the three images of the fluorescent microsphere before and after motion on the charge-coupled image sensor, and determine the attitude vector of the six-axis precision calibration displacement stage corresponding to the same ratios of the three XY axes before and after motion, including: Make the six - dimensional precision calibration displacement stage perform translational motions in two non - parallel directions, and obtain the ratios of the three XY - axis widths corresponding to three images before and after the movement of the fluorescent microsphere on the charge - coupled image sensor. If the three XY - axis width ratios are the same, the plane determined by the two movement directions is a longitudinal object plane of the fluorescence microscope; traverse the pitch state and yaw attitude of the six - dimensional precision calibration displacement stage with the smallest step size. In each attitude case, perform the above - mentioned translational motion and obtain the corresponding three XY - axis width ratios of the images, and then determine the attitude vector of the six - dimensional precision calibration displacement stage when the three XY - axis width ratios before and after the movement are the same.

[0010] Optionally, make the six - dimensional precision calibration displacement stage move back and forth along the direction of the attitude vector, and ensure that the fluorescent microsphere can be imaged on the charge - coupled image sensor, and obtain the functional relationship between the height of the longitudinal object plane and the XY - axis width ratio of the fluorescent microsphere, that is, the longitudinal object plane height function; on each longitudinal object plane, translate the six - dimensional precision calibration displacement stage by an actual displacement value, determine the measured displacement value of the corresponding fluorescent microsphere imaged on the charge - coupled image sensor, and according to the actual displacement value and the measured displacement value, obtain the microscopic magnification function, including: Make the six - dimensional precision calibration displacement stage move back and forth along the direction of the attitude vector, and ensure that the fluorescent microsphere can be imaged on the charge - coupled image sensor, and obtain the functional relationship between the height of the longitudinal object plane and the XY - axis width ratio of the fluorescent microsphere, that is, the longitudinal object plane height function; on each longitudinal object plane, translate the six - dimensional precision calibration displacement stage by an actual displacement value, obtain the measured displacement value of the fluorescent microsphere on the charge - coupled image sensor, divide the measured displacement value of the fluorescent microsphere by the actual displacement value to obtain the microscopic magnification on each longitudinal object plane, and determine the microscopic magnification function according to the different microscopic magnifications corresponding to different longitudinal object plane heights.

[0011] Optionally, fix the first gear and the second gear on the first rotating shaft and the second rotating shaft of the upper turntable respectively, and fix a bracket with a gear transmission shaft on one side on the tabletop of the lower turntable, including: Fix the first gear and the second gear on the first rotating shaft and the second rotating shaft of the upper turntable respectively, and fix a bracket with a gear transmission shaft on one side on the tabletop of the lower turntable. When the lower turntable rotates, it drives the upper turntable and the bracket to rotate. The bracket is fixed to the gear transmission shaft through a bearing. The two ends of the gear transmission shaft are engaged with the first gear and the second gear of the upper turntable respectively. When the first rotating shaft of the upper turntable rotates, the rotational force is transmitted to the gear transmission shaft through the first gear, causing the gear transmission shaft to rotate, and then driving the second gear to rotate, so that the second rotating shaft rotates.

[0012] Optionally, fix the microscope on a six-dimensional precision adjustment displacement stage, fix the substrate with fluorescent microspheres on the tabletop of a micro translation adjustment stage, and fix the micro translation adjustment stage on the upper turntable, the first rotating shaft, the second rotating shaft, and the lower turntable rotating shaft in sequence, including: Fix the microscope on a six-dimensional precision adjustment displacement stage; fix the substrate with fluorescent microspheres on the tabletop of a micro translation adjustment stage, and finely adjust the spatial position of the fluorescent microspheres through the micro translation adjustment stage; fix the micro translation adjustment stage on the upper turntable, the first rotating shaft, the second rotating shaft, and the lower turntable rotating shaft in sequence. After each fixation of the micro translation adjustment stage, start the upper turntable or the lower turntable motor to rotate the corresponding rotating shaft one full circle to ensure that the fluorescent microspheres are imaged by the microscope during one full circle rotation of the rotating shaft.

[0013] Optionally, fix the micro translation adjustment stage with fluorescent microspheres and substrate on the lower turntable rotating shaft, start the lower turntable motor, make the lower turntable rotating shaft rotate a minimum step angle and then stop, record the imaging of the fluorescent microspheres by the microscope, determine the centroid coordinates and the XY-axis width ratio in the imaging plane coordinates of the charge-coupled image sensor through a two-dimensional Gaussian function, determine the microscopic magnification corresponding to the longitudinal object plane height where the fluorescent microspheres are located according to the XY-axis width ratio, and determine the spatial coordinate values of the fluorescent microspheres mapped to the imaging plane coordinates of the charge-coupled image sensor according to the centroid coordinates and the microscopic magnification, including: Fix the micro translation adjustment stage with fluorescent microsphere substrate on the lower turntable rotating shaft, start the lower turntable motor, make the lower turntable rotating shaft rotate a minimum step angle and then stop, record the imaging of the fluorescent microspheres by the microscope, obtain the centroid coordinates and the XY-axis width ratio in the imaging plane coordinates of the charge-coupled image sensor by fitting the imaging light intensity with a two-dimensional Gaussian function, determine the value of the microscopic magnification function corresponding to the longitudinal object plane height where the fluorescent microspheres are located at this time through the XY-axis width ratio, that is, the microscopic magnification at this time, divide the centroid coordinates by the magnification to obtain the spatial coordinate values of the fluorescent microspheres mapped to the imaging plane coordinates of the charge-coupled image sensor; and so on. After the lower turntable rotates one full circle, obtain a series of corresponding spatial coordinate values of the fluorescent microspheres, perform a plane elliptic function fitting on the series of spatial coordinate values of the fluorescent microspheres to obtain a plane mapping spatial trajectory, record the length values of the major and minor axes of the fitted ellipse at this time, traverse the pitch attitude and yaw attitude of the six-dimensional precision adjustment displacement stage with the smallest step, and obtain a length value of the major and minor axes of the fitted ellipse for each attitude. When the major axis and minor axis of the fitted ellipse corresponding to a certain attitude are the minimum values in all traversed pitch attitudes and yaw attitudes, that is, the length of the spatial plane trajectory mapped when the rotation axis is perpendicular to the imaging plane is the shortest, at this time, the rotation axis of the lower turntable is parallel to the imaging optical axis of the fluorescence microscope.

[0014] Optionally, a first reference coordinate system is constructed according to the spatial coordinate values, and the spatial straight-line equation of the rotation axis of the lower turntable is determined in the first reference coordinate system to obtain the radial runout value within a complete rotation period of the rotation axis of the lower turntable, including: In the case where the rotation axis of the lower turntable is parallel to the imaging optical axis of the microscope, on the premise of obtaining the imaging light intensity of the fluorescent microspheres corresponding to all the step rotations of the lower turntable and the coordinate of the imaging plane of the charge-coupled image sensor, the centroid coordinate and the ratio of the widths of the X and Y axes are obtained by two-dimensional Gaussian fitting of the imaging light intensity in the coordinate of the imaging plane of the charge-coupled image sensor. The corresponding longitudinal object plane height value and the microscopic magnification are obtained through the ratio of the widths of the X and Y axes. The centroid coordinate is divided by the microscopic magnification to obtain the spatial coordinate value of the fluorescent microspheres mapped to the coordinate of the imaging plane of the charge-coupled image sensor. Let the center coordinate obtained by fitting the spatial coordinate value plane with an elliptic function be ( x 拟 , y 拟 ), the origin of the coordinate system of the imaging plane of the charge-coupled image sensor is translated to the intersection coordinate of the imaging optical axis and the imaging plane of the charge-coupled image sensor ( x o , y o ), and then translated along the direction of the imaging optical axis to the focal longitudinal object plane. The corresponding coordinate system is denoted as the first reference coordinate system X 基 Y 基 Z 基 , and the first reference coordinate system is the measurement coordinate system of the microscope at this time; the spatial coordinate value of the fluorescent microspheres mapped to the coordinate of the imaging plane of the charge-coupled image sensor is subtracted from the intersection coordinate ( x o , y o ), to obtain the XY-axis plane coordinate value of the fluorescent microspheres in the first reference coordinate system X 基 Y 基 Z 基 , and the obtained longitudinal object plane height value is the Z-axis coordinate value in the first reference coordinate system X 基 Y 基 Z 基 ; obtain the reference coordinate system X 基 Y 基 Z 基 passing through ( x 拟 - x o , y 拟 - y o, the spatial straight line equation passing through the point (0, 0) and with the direction of (0, 0, 1), that is, the rotation axis of the lower turntable; in the first reference coordinate system X 基 Y 基 Z 基 In it, for the lower turntable rotation axis, the axial runout value within a complete rotation period is the difference between the Z-axis value of the fluorescent microsphere corresponding to each rotation step angle of the lower turntable rotation axis and the Z-axis value of the fluorescent microsphere at the moment of non-rotation. The radial runout value within a complete rotation period of the lower turntable rotation axis is the difference between the distance from the XY-axis plane coordinates of the fluorescent microsphere corresponding to each rotation step angle of the lower turntable rotation axis to the origin and the distance from the coordinate point on the fitting plane ellipse function corresponding to the rotation step angle to the origin.

[0015] Optionally, set the lower turntable rotation axis to be stationary, record the spatial coordinate values of the fluorescent microsphere in the first reference coordinate system at this time, construct the motion coordinate system of the six-dimensional precision adjustment displacement stage, determine the first vector value of the unit vector on the X-axis of the motion coordinate system in the first reference coordinate system, and determine the first coordinate value of the origin of the motion coordinate system in the first reference coordinate system. Make the six-dimensional precision adjustment displacement stage rotate by a first angle around the X-axis of the motion coordinate system. Rotate the unit vector in the first reference coordinate system around the first vector value by the first angle to obtain the second vector value, including: Ensure that the lower turntable rotation axis is stationary, and record the spatial coordinate values of the fluorescent microsphere in the first reference coordinate system X 基 Y 基 Z 基 at this time ; Construct the motion coordinate system X 调 Y 调 Z 调 of the six-dimensional precision adjustment displacement stage 28. Assume that the first vector value of the unit vector on the X-axis of the motion coordinate system X 调 Y 调 Z 调 in the first reference coordinate system X 基 Y 基 Z 基 is ( u X , u Y ,u Z ), and the first coordinate value of the origin of the coordinate system X 调 Y 调 Z 调 in the first reference coordinate system X 基 Y 基 Z 基 is ( o X , o Y ,oZ ), rotate the six - dimensional precision adjustment displacement stage around the X - axis of the moving coordinate system by a first angle, that is, rotate by the first angle around the first vector value ( 调 Y 调 Z 调 in the moving coordinate system X 基 Y 基 Z 基 ), and rotate the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) in the first reference coordinate system X u X , u Y ,u Z ) by the first angle; subtract the first coordinate value ( 基 Y 基 Z 基 ) from the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) in the first reference coordinate system X u X , u Y ,u Z ), and then right - multiply by the first rotation transformation matrix respectively to obtain the second vector values corresponding to the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) after rotating by the first angle around the first vector value ( 基 Y 基 Z 基 ) in the first reference coordinate system X o X , o Y ,o Z ), and the expression of the first rotation transformation matrix is: u X , u Y ,u Z ) in the first reference coordinate system X 基 Y 基 Z 基 ; where Among them, u X , u Y , u Z are the X - axis, Y - axis, and Z - axis values of the first vector value respectively, θ is the first angle; Rotate the first reference coordinate system X 基 Y基 Z 基 The unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) in o X , o Y ,o Z ), respectively, subtracted from the first coordinate value ( o X , - o Y , - o Z ), (- o X , 1 - o Y , - o Z ), and (- o X , - o Y , 1 - o Z ). Then, after multiplying each of these results on the right by the first rotation transformation matrix, the second vector values are obtained. Then, after adding each of the second vector values to the first coordinate value ( o X , o Y ,o Z ), the results are ( i x , i y , i z ), ( j x , j y , j z ), and ( k x , k y , k z ). Subtracting the origin coordinates (0, 0, 0) from the first coordinate value ( o X , o Y ,o Z ), multiplying the result on the right by the first rotation transformation matrix, and then adding the result to the first coordinate value ( o X , oY ,o Z ) Add them to get ( t x , t y , t z ). Then, in the first reference coordinate system X 基 Y 基 Z 基 , the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) rotate around the first vector value ( u X , u Y ,u Z ) by the first angle, and the majority of the second vector values in the first reference coordinate system X 基 Y 基 Z 基 are respectively ( i x - t x , i y - t y , i z - t z ), ( j x - t x , j y - t y , j z - t z ), and ( k x - t x , k y - t y , k z - t z ).

[0016] Optionally, rotate the first reference coordinate system around the X-axis of the moving coordinate system by the first angle to obtain the measurement coordinate system of the microscope, determine the spatial coordinate values of the fluorescent microspheres in the measurement coordinate system, and obtain the spatial coordinate relationship of the fluorescent microspheres before and after the first angle rotation of the six-dimensional precision adjustment displacement stage, including: The six-dimensional precision adjustment displacement stage rotates around the X-axis of the moving coordinate system X 调 Y 调 Z 调 by a first angle, driving the fluorescence microscope to rotate around the X-axis of the moving coordinate system X 调 Y 调 Z 调 by the first angle. At this time, the first reference coordinate system X θ 基 Y 基 Z 基 also rotates around the X-axis of the moving coordinate system X 调 Y 调 Z 调 by a first angle, obtaining the measurement coordinate system X of the microscope θ Y θ Z θ ; similar to the case where the first reference coordinate system X 基 Y 基 Z 基 in step S8 is used as the measurement coordinate system of the microscope, obtaining the spatial coordinate values of the fluorescence microsphere in the measurement coordinate system X of the microscope θ Y θ Z θ ( x θ , y θ , z θ ), obtaining the spatial coordinate relationship of the fluorescence microsphere before and after the rotation of the six-dimensional precision adjustment displacement stage. The expression is as follows: where, ( x θ , y θ , z θ ) are the spatial coordinate values of the fluorescence microsphere in the measurement coordinate system X of the microscope θ Y θ Z θ ; ( i x - t x , i y - t y , i z - t z ), ( j x - t x , j y ​- t y , j z - t z ), and ( k x - t x , k y - t y , k z - t z ), respectively, are the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) in the first reference coordinate system X 基 Y 基 Z 基 rotated by the first vector value ( u X , u Y ,u Z ) by the first angle, and their second vector values in the first reference coordinate system X 基 Y 基 Z 基 ; is the spatial coordinate value of the fluorescent microspheres in the first reference coordinate system X 基 Y 基 Z 基 when the rotating shaft of the lower turntable is stationary.

[0017] Optionally, rotate the six-axis precision adjustment displacement stage back to the starting posture, determine the third vector value of the unit vector on the Y-axis of the moving coordinate system of the six-axis precision adjustment displacement stage in the first reference coordinate system, rotate the six-axis precision adjustment displacement stage by the second angle around the Y-axis of the moving coordinate system, obtain the spatial coordinate relationship of the fluorescent microspheres before and after the six-axis precision adjustment displacement stage rotates by the second angle, and obtain the first vector value, the first coordinate value, and the third vector value by the least squares method, including: Rotate the six-axis precision adjustment displacement stage back to the starting posture of step S9, and assume that the unit vector on the Y-axis of the moving coordinate system X 调 Y 调 Z 调 of the six-axis precision adjustment displacement stage in the first reference coordinate system X 基 Y 基 Z 基 is ( v X , v Y ,v Z), causing the six - dimensional precision adjustment displacement stage to rotate around the Y - axis of the moving coordinate system X 调 Y 调 Z 调 by a second angle; similarly, obtain the spatial coordinate relationship of the fluorescent microspheres before and after the rotation of the six - dimensional precision adjustment displacement stage similar to the expression (Ⅱ); obtain six relationships about nine unknowns, that is, the first vector value ( u X , u Y ,u Z ), the first coordinate value ( o X , o Y ,o Z ), and the third vector value ( v X , v Y ,v Z ); repeat steps S9 to S11, rotate more different first angles and second angles to obtain more relationships than the number of nine unknowns, thereby constructing an over - determined system of equations, and calculate the first vector value ( u X , u Y ,u Z ), the first coordinate value ( o X , o Y ,o Z ), and the third vector value ( v X , v Y , v Z ) through the least - squares method.

[0018] Optionally, fix the micro - translation adjustment stage with the fluorescent microspheres and the substrate on the first rotating shaft of the upper turntable, start the motor of the upper turntable to control the rotation of the first rotating shaft, construct a second reference coordinate system, determine the spatial straight - line equation of the rotation axis on the motor side of the upper turntable in the second reference coordinate system, and obtain the axial and radial run - out values within a complete rotation period, including: Fix the micro - translation adjustment stage with the fluorescent microsphere substrate on the first rotating shaft of the upper turntable, start the motor of the upper turntable to control the rotation of the first rotating shaft, and the remaining operations are the same as steps S7 and S8. At this time, the measurement coordinate system of the microscope is X’ 基 Y’基 Z' 基 , that is, the second reference coordinate system is X' 基 Y' 基 Z' 基 ; because the imaging fluorescence of the fluorescent microspheres is transmitted to the side beam incident surface of the standard 45-degree beam splitter cube for imaging, due to the mirroring effect of the beam splitting surface of the standard 45-degree beam splitter cube, the obtained is the spatial coordinate values of the symmetric mirror image of the fluorescent microspheres in the second reference coordinate system X' 基 Y' 基 Z' 基 , and the spatial coordinate values are uniformly expressed as ( x’ , y’, z’ ); according to the distance D between the longitudinal object plane of the focus of the microscope and the center point of the beam splitting surface in step S1, the spatial coordinate values of the actual fluorescent microspheres in the second reference coordinate system X' 基 Y' 基 Z' 基 are ( x’ , y’ - D ,z’ + D), similar to step S8, in the second reference coordinate system X' 基 Y' 基 Z' 基 , the spatial straight line equation of the rotation axis on the upper turntable motor side and the axial and radial runout values within a complete rotation period are obtained.

[0019] Optionally, according to the six-dimensional precision adjustment displacement stage, determine the yaw angle and pitch angle of the second reference coordinate system relative to the first reference coordinate system, rotate the unit vectors in the first reference coordinate system by the yaw angle and pitch angle, obtain the spatial coordinate values of the fluorescent microspheres in the second reference coordinate system in the first reference coordinate system, and convert the spatial straight line equation of the upper turntable rotation axis into the spatial straight line equation in the first coordinate system, including: Since the second reference coordinate system X' 基 Y' 基 Z' 基 is determined by the principle that the spatial plane trajectory length is the shortest when the rotation axis is perpendicular to the imaging plane, so the second reference coordinate system X' 基 Y' 基 Z' 基 and the first reference coordinate system X 基 Y 基 Z 基 will have an attitude difference, and the attitude difference is due to the attitude of the six-dimensional precision adjustment displacement stage corresponding to the first reference coordinate system X 基 Y 基 Z 基 and the attitude of the six-dimensional precision adjustment displacement stage corresponding to the second reference coordinate system X' 基 Y' 基Z’ 基 The corresponding six - dimensional precision adjustment displacement stage has a yaw angle and a pitch angle. The yaw angle and the pitch angle are determined by the six - dimensional precision adjustment displacement stage. Denote the first reference coordinate system as X 基 Y 基 Z 基 Yaw θ’ and pitch δ’ After the angles, it becomes the second reference coordinate system X’ 基 Y’ 基 Z’ 基 , and the corresponding second rotation transformation matrix to be right - multiplied is: Among them, θ’ is the yaw angle, δ’ is the pitch angle, ([[]] u X ,, u Y ,u Z ) is the unit vector on the X - axis of the moving coordinate system X 调 Y 调 Z 调 of the six - dimensional precision adjustment displacement stage in the first vector value in the first reference coordinate system X 基 Y 基 Z 基 , ([[]] v X ,, v Y ,v Z ) is the unit vector on the Y - axis of the moving coordinate system X 调 Y 调 Z 调 of the six - dimensional precision adjustment displacement stage in the third vector value in the first reference coordinate system X 基 Y 基 Z 基 ; Through the second rotation transformation matrix and the first coordinate value of the origin of the moving coordinate system X 调 Y 调 Z 调 in the first reference coordinate system X 基 Y 基 Z 基 ([[]] o X ,, o Y ,o Z ), similar to the operation in step S9, the first reference coordinate system X 基 Y 基 Z 基The unit vectors (1, 0, 0), (0, 1, 0), (0, 0, 1) and the origin (0, 0, 0) are respectively converted to ( i' x , i' y , i' z ), ( j' x , j' y , j' z ), ( k' x , k' y , k' z ) and ( t' x , t' y , t' z ), so as to obtain the unit vectors (1, 0, 0), (0, 1, 0) and (0, 0, 1) in the first reference coordinate system X 基 Y 基 Z 基 after yawing θ’ and pitching δ’ angles, and in the first reference coordinate system X 基 Y 基 Z 基 they respectively become ( i' x - t' x , i' y - t' y , i' z - t' z ), ( j' x - t' x , j' y - t' y , j' z - t' z ) and ( k' x - t' x , k' y - t' y , k'z - t' z ), the spatial coordinates of the fluorescent microspheres in the second reference coordinate system X' 基 Y' 基 Z' 基 are obtained as ( x’ , y’ -D ,z’ +D) and corresponding to the spatial coordinate values ( 基 Y 基 Z 基 ) in the first reference coordinate system X x’ 基 , y’ 基 , z’ 基 ), and the expression is: ; For any two coordinate values on the spatial straight line equation of the rotation axis on the upper turntable motor side in the second reference coordinate system X' 基 Y' 基 Z' 基 , after being converted by the expression (IV), their coordinate values in the first reference coordinate system X 基 Y 基 Z 基 are obtained, thereby determining the spatial straight line equation in the first reference coordinate system X 基 Y 基 Z 基 , that is, realizing the determination of the spatial straight line equations of the lower turntable rotation axis and the upper turntable motor side rotation axis in the same coordinate system.

[0020] Optionally, fix the micro translation adjustment stage with the fluorescent microspheres and the substrate on the second rotating shaft of the upper turntable, start the lower turntable motor, rotate 180 degrees to symmetrically interchange the positions of the upper turntable encoder side and the upper turntable motor side, obtain the axial and radial runout values within a complete rotation period, determine the spatial straight line equations of the lower turntable rotation axis and the upper turntable encoder side rotation axis in the first reference coordinate system, and realize the determination of the spatial straight line equations of the lower turntable rotation axis, the upper turntable motor side rotation axis, and the upper turntable encoder side rotation axis and the error detection within a complete rotation period in the same reference coordinate system, including: Fix the micro translation adjustment stage with the fluorescent microsphere substrate on the second rotating shaft of the upper turntable, start the lower turntable motor, rotate 180 degrees to symmetrically interchange the positions of the upper turntable encoder side and the upper turntable motor side. Similar to steps 12 and 13, obtain the axial and radial runout values within a complete rotation period; in the first reference coordinate system X 基 Y 基 Z 基Determine the spatial straight-line equations of the rotation axis of the lower turntable and the rotation axis on the encoder side of the upper turntable, realize the error detection of the rotation axis of the lower turntable, the rotation axis on the motor side of the upper turntable, and the rotation axis on the encoder side within a complete rotation cycle, and determine the spatial straight-line equations of the rotation axis of the lower turntable, the rotation axis on the motor side of the upper turntable, and the rotation axis on the encoder side in the same first reference coordinate system X 基 Y 基 Z 基 under.

[0021] In a second aspect, the present application also provides an overall measurement optical path connecting the upper rotating shaft type laser tracker turntable shaft error detection device for performing the overall measurement optical path connecting the upper rotating shaft type laser tracker turntable shaft error detection method as described in any one of the first aspects, including: a microscope, a fluorescent microsphere, a substrate, and a six-dimensional precision calibration displacement stage, wherein the microscope is located above the fluorescent microsphere, the fluorescent microsphere is fixed on the substrate, and the substrate is fixed on the six-dimensional precision calibration displacement stage.

[0022] The present application has the following characteristics and good effects: The present application realizes the determination of the spatial straight-line equations of the upper and lower turntable axes of the overall measurement optical path connecting the upper rotating shaft type laser tracker in one coordinate system and the detection of the shaft diameter jump within a complete rotation cycle, making necessary technical preparations for realizing the compensation of the turntable shaft error of the upper laser tracker in the overall measurement optical path, improving the tracking accuracy and stability of the laser tracker.

[0023] To make the above features and advantages of the invention more obvious and understandable, specific embodiments are hereinafter given and described in detail in conjunction with the accompanying drawings. Description of the Drawings

[0024] Figure 1 It is a schematic structural diagram of the microscope structure and its own three-dimensional measurement calibration in the overall measurement optical path connecting the upper rotating shaft type laser tracker turntable shaft error detection device provided in an embodiment of the present application; Figure 2 It is a schematic structural diagram of the six-dimensional precision calibration displacement stage in the overall measurement optical path connecting the upper rotating shaft type laser tracker turntable shaft error detection device provided in an embodiment of the present application; Figure 3 It is a schematic structural diagram of the overall measurement optical path connecting the upper rotating shaft type laser tracker turntable shaft error detection device provided in an embodiment of the present application; Figure 4 It is a flowchart of the overall measurement optical path connecting the upper rotating shaft type laser tracker turntable shaft error detection method provided in an embodiment of the present application; In the figure: 1 objective lens, 2 cylindrical lens, 3 charge-coupled image sensor, 4 imaging optical axis, 5 standard 45-degree beam-splitting cube mirror block, 6 beam-splitting surface, 7 fluorescence excitation light source, 8 microscope, 9 fluorescent microsphere, 10 substrate, 11 six-dimensional precision calibration displacement stage, 12 bottom beam incident surface, 13 side beam incident surface, 14 focal longitudinal object plane, 15 upper turntable, 16 lower turntable, 17 lower turntable rotation axis, 18 first rotation axis, 19 second rotation axis, 20 lower turntable rotation axis, 21 motor side rotation axis, 22 encoder side rotation axis, 23 first gear, 24 second gear, 25 gear transmission shaft, 26 bracket, 27 bearing, 28 six-dimensional precision adjustment displacement stage, 29 micro translation adjustment stage. Specific implementation mode

[0025] To make the objectives and technical solutions of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0026] Please refer to Figure 1 and Figure 2 , the present application provides a device for detecting the rotation axis error of an upper-rotating-axis type laser tracker in the overall measurement optical path connection, which may include: a microscope 8, a fluorescent microsphere 9, a substrate 10, and a six-dimensional precision calibration displacement stage 11. Among them, the microscope 8 is located above the fluorescent microsphere 9, the fluorescent microsphere 9 is fixed on the substrate 10, and the substrate 10 is fixed on the six-dimensional precision calibration displacement stage 11.

[0027] As an example, the fluorescent microsphere 9 may be a sub-millimeter-sized fluorescent microsphere.

[0028] As an example, the substrate 10 may be a planar substrate.

[0029] As an example, the microscope 8 includes: an objective lens 1, a cylindrical lens 2, a charge-coupled image sensor 3, a standard 45-degree beam-splitting cube 5, and a fluorescence excitation light source 7. Among them, the cylindrical lens 2 is placed 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 of the imaging surface of the charge-coupled image sensor 3. A standard 45-degree beam-splitting cube 5 is placed under the objective lens 1. The standard 45-degree beam-splitting cube 5 includes a beam-splitting surface 6. The beam-splitting surface 6 forms a standard 45 degrees with the bottom surface of the standard 45-degree beam-splitting cube. The edge of the beam-splitting surface 6 is parallel to the X-axis of the imaging surface of the charge-coupled image sensor 3. After the fluorescence beam is reflected or transmitted by the beam-splitting surface 6, it can enter the objective lens 1, and after passing through the cylindrical lens 2, it is received by the charge-coupled image sensor 3. A fluorescence excitation light source 7 is placed on the mirror side at an angle of 45 degrees with the beam-splitting surface 6. After the fluorescence excitation light source 7 is turned on, the light beam of the light source can be reflected or transmitted by the standard 45-degree beam-splitting cube 5. The imaging optical axis of the objective lens 1 passes through the center point of the beam-splitting surface 6 of the standard 45-degree beam-splitting cube 5.

[0030] As an example, the microscope 8 can be a fluorescence microscope. The spatial position of the microscope 8 is fixed, and the microscope 8 has an astigmatic imaging function.

[0031] As an example, the objective lens 1 can include: an imaging optical axis 4, and the normal vector of the imaging surface of the charge-coupled image sensor 3 is parallel to the imaging optical axis 4 of the objective lens 1.

[0032] As an example, the standard 45-degree beam-splitting cube 5 can further include: a bottom beam incident surface 12 and a side beam incident surface 13. The bottom beam incident surface 12 is located at the bottom of the standard 45-degree beam-splitting cube 5 of the microscope 8, and the side beam incident surface 13 is located at the side of the standard 45-degree beam-splitting cube 5 of the microscope 8. The bottom beam incident surface 12 and the side beam incident surface 13 can be used to receive fluorescence.

[0033] As an example, the microscope 8 can further include: a focal longitudinal object plane 14, which is an object plane perpendicular to the imaging optical axis at the focal point. The distance between the focal longitudinal object plane 14 and the center point of the beam-splitting surface 6 is D.

[0034] As an example, please refer to Figure 3 , the overall measurement optical path is connected to the laser tracker turntable axis error detection device, and can further include: an upper turntable 15, a lower turntable 16, a lower turntable axis 17, and a six-dimensional precision adjustment displacement stage 28. Among them, the lower turntable axis 17 is located above the lower turntable 16, the upper turntable 15 is located above the lower turntable 16, and the six-dimensional precision adjustment displacement stage 28 is located above the upper turntable 15.

[0035] As an example, the overall measurement optical path is connected to a laser tracker turntable shaft error detection device, and may further include: a first gear 23, a second gear 24, a gear transmission shaft 25, a first shaft 18, a second shaft 19, a bracket 26, a bearing 27, and a micro translation adjustment stage 29. Among them, the first gear 23 is fixed on the first shaft 18, the second gear 24 is fixed on the second shaft 19, and the first shaft 18 and the second shaft 19 are respectively fixed on both sides of the upper turntable 15; the gear transmission shaft 25 is arranged above the bracket 26, the bracket 26 is fixed on the tabletop of the lower turntable 16, and the micro translation adjustment stage 29 is arranged on the bracket 26; when the lower turntable 16 rotates, it can drive the upper turntable 15 to rotate and can also drive the bracket 26 to rotate. The bracket 26 is fixed to the gear transmission shaft 25 through the bearing 27. The two ends of the gear transmission shaft 25 are respectively engaged with the first gear 23 and the second gear 24 on the upper turntable 15. When the first shaft 18 of the upper turntable 15 rotates, the rotational force can be transmitted to the gear transmission shaft 25 through the first gear 23, causing the gear transmission shaft 25 to rotate, and then driving the second gear 24 to rotate, thereby causing the second shaft 19 to rotate.

[0036] As an example, the substrate 10 may be fixed on the micro translation adjustment stage 29.

[0037] As an example, the first gear 23 may be a motor side gear, and the second gear 24 may be an encoder side gear.

[0038] As an example, the first shaft 18 may be a motor side shaft, and the second shaft 19 may be an encoder side shaft.

[0039] As an example, please refer to Figure 3 , the lower turntable 16 may include: a lower turntable rotation axis 20, and the lower turntable 16 rotates around the lower turntable rotation axis 20.

[0040] As an example, during the rotation of the upper turntable 15 and the lower turntable 16, the microscope 8 for detecting the fluorescent microspheres 9 will not be touched by any object.

[0041] As an example, please refer to Figure 3 , the overall measurement optical path is connected to a laser tracker turntable shaft error detection device, and may further include: a motor side rotation axis 21 and an encoder side rotation axis 22. Among them, the first shaft 18 and the first gear 23 rotate around the motor side rotation axis 21; the second shaft 19 and the second gear 24 rotate around the encoder side rotation axis 22.

[0042] In one embodiment, please refer to Figure 4, this application provides a method for detecting the shaft axis error of the turntable of a laser tracker in the connection of an overall measurement optical path. The method for detecting the shaft axis error of the turntable of a laser tracker in the connection of an overall measurement optical path may include the following steps: Step S1 to Step S14.

[0043] Step S1: Construct a microscope using an objective lens, a cylindrical lens, a charge-coupled image sensor, a standard 45-degree beam-splitting cube mirror block, and a fluorescence excitation light source.

[0044] Step S2: Set up the microscope, fluorescence microspheres, planar substrate, and six-axis precision calibration displacement stage so that the fluorescence microspheres are imaged on the charge-coupled image sensor.

[0045] Step S3: Make the six-axis precision calibration displacement stage perform two translational motions with non-parallel directions of motion, obtain the ratios of the widths of the three XY axes corresponding to the three images of the fluorescence microspheres before and after motion on the charge-coupled image sensor, and determine the attitude vector of the six-axis precision calibration displacement stage when the ratios of the widths of the three XY axes are the same before and after motion.

[0046] Step S4: Make the six-axis precision calibration displacement stage move back and forth along the direction of the attitude vector and ensure that the fluorescence microspheres can be imaged on the charge-coupled image sensor, obtain the functional relationship between the longitudinal object plane height and the ratio of the widths of the XY axes, that is, the longitudinal object plane height function; on each longitudinal object plane, translate the six-axis precision calibration displacement stage by an actual displacement value, determine the measured displacement value of the corresponding fluorescence microspheres imaged on the charge-coupled image sensor, and obtain the microscopic magnification function according to the actual displacement value and the measured displacement value.

[0047] Step S5: Fix the first gear and the second gear on the first shaft and the second shaft of the upper turntable respectively, and fix a bracket with a gear transmission shaft on one side on the tabletop of the lower turntable.

[0048] Step S6: Fix the microscope on a six-axis precision adjustment displacement stage, fix the substrate with fluorescence microspheres on the tabletop of a micro translation adjustment stage, and sequentially fix the micro translation adjustment stage on the upper turntable, the first shaft, the second shaft, and the shaft of the lower turntable.

[0049] Step S7: Fix the micro translation adjustment stage with fluorescence microspheres and substrate on the shaft of the lower turntable, start the lower turntable motor, make the shaft of the lower turntable rotate by a minimum step angle and then stop, record the image of the fluorescence microspheres by the microscope, determine the centroid coordinates and the ratio of the widths of the XY axes in the imaging plane coordinates of the charge-coupled image sensor through a two-dimensional Gaussian function, determine the microscopic magnification corresponding to the longitudinal object plane height where the fluorescence microspheres are located according to the ratio of the widths of the XY axes, and determine the spatial coordinate values of the fluorescence microspheres mapped to the imaging plane coordinates of the charge-coupled image sensor according to the centroid coordinates and the microscopic magnification.

[0050] Step S8: Construct a first reference coordinate system based on the spatial coordinate values, determine the spatial straight-line equation of the rotation axis of the lower turntable in the first reference coordinate system, and obtain the radial runout value within a complete rotation period of the lower turntable rotating shaft.

[0051] Step S9: Set the rotating shaft 17 of the lower turntable to be stationary, record the spatial coordinate values of the fluorescent microspheres in the first reference coordinate system at this time, construct the motion coordinate system of the six-dimensional precision adjustment displacement stage, determine the first vector value of the unit vector on the X-axis of the motion coordinate system in the first reference coordinate system, determine the first coordinate value of the origin of the motion coordinate system in the first reference coordinate system, rotate the six-dimensional precision adjustment displacement stage by a first angle around the X-axis of the motion coordinate system, and rotate the unit vector in the first reference coordinate system by the first angle around the first vector value to obtain a second vector value.

[0052] Step S10: Rotate the first reference coordinate system by the first angle around the X-axis of the motion coordinate system to obtain the measurement coordinate system of the microscope, determine the spatial coordinate values of the fluorescent microspheres in the measurement coordinate system, and obtain the spatial coordinate relationship of the fluorescent microspheres before and after the six-dimensional precision adjustment displacement stage rotates by the first angle.

[0053] Step S11: Rotate the six-dimensional precision adjustment displacement stage back to the starting attitude, determine the third vector value of the unit vector on the Y-axis of the motion coordinate system of the six-dimensional precision adjustment displacement stage in the first reference coordinate system, rotate the six-dimensional precision adjustment displacement stage by a second angle around the Y-axis of the motion coordinate system to obtain the spatial coordinate relationship of the fluorescent microspheres before and after the six-dimensional precision adjustment displacement stage rotates by the second angle, and obtain the first vector value, the first coordinate value, and the third vector value through the least squares method.

[0054] Step S12: Fix the micro translation adjustment stage with the fluorescent microspheres and the substrate on the first rotating shaft of the upper turntable, start the motor of the upper turntable to control the rotation of the first rotating shaft, construct a second reference coordinate system, determine the spatial straight-line equation of the rotation axis on the motor side of the upper turntable in the second reference coordinate system, and obtain the axial and radial runout values within a complete rotation period.

[0055] Step S13: Determine the yaw angle and pitch angle of the second reference coordinate system with respect to the first reference coordinate system according to the six-dimensional precision adjustment displacement stage, rotate the unit vector in the first reference coordinate system by the yaw angle and pitch angle to obtain the spatial coordinate value of the spatial coordinate of the fluorescent microspheres in the second reference coordinate system in the first reference coordinate system, and convert the spatial straight-line equation of the rotation axis of the upper turntable into the spatial straight-line equation in the first coordinate system.

[0056] Step S14: Fix the micro translation adjustment stage with fluorescent microspheres and the substrate on the second rotating shaft of the upper turntable, and start the lower turntable motor. Rotate 180 degrees to symmetrically interchange the positions of the encoder side and the motor side of the upper turntable, obtain the axial and radial runout values within a complete rotation period, determine the spatial straight-line equations of the rotation axis of the lower turntable and the rotation axis of the encoder side of the upper turntable in the first reference coordinate system, and realize the determination of the spatial straight-line equations of the rotation axis of the lower turntable, the rotation axis of the motor side of the upper turntable, and the rotation axis of the encoder side of the upper turntable in the same reference coordinate system and the error detection within a complete rotation period.

[0057] In the overall measurement optical path connection of the turntable shaft error detection method of the present application, by using components such as an objective lens and a cylindrical lens to construct a microscope, cooperating with fluorescent microspheres as measurement marks, and by analyzing their imaging characteristics at different object surface heights and displacements, a longitudinal object surface height function and a microscopic magnification function are established, providing an accurate measurement basis for subsequent error detection; during the turntable shaft error detection process, by respectively fixing the fluorescent microsphere substrate on the rotating shaft of the lower turntable, the first rotating shaft and the second rotating shaft of the upper turntable, combined with multi-coordinate system conversion and spatial straight-line equation construction, error parameters such as the radial runout value and the axial runout value of each rotating shaft of the lower turntable and the upper turntable can be comprehensively detected; through the rotation of the second displacement stage and coordinate system conversion, the detection of the rotation axis errors of the motor side and the encoder side of the upper turntable in the same reference coordinate system is realized, eliminating the errors caused by different measurement references, improving the accuracy and comparability of the detection results, and being able to effectively detect various errors of the turntable shaft within a complete rotation period, providing reliable technical support for the high-precision manufacturing and calibration of the laser tracker turntable.

[0058] In step S1, please refer to Figure 4 step S1 in, use an objective lens, a cylindrical lens, a charge-coupled image sensor, a standard 45-degree beam-splitting cube mirror block and a fluorescence excitation light source to construct a microscope.

[0059] As an example, please refer to Figure 1, a microscope 8 with an astigmatic imaging function and a fixed spatial position is constructed by using an objective lens 1, a cylindrical lens 2, a charge-coupled image sensor 3, a standard 45-degree beam-splitting cube 5, and a fluorescence excitation light source 7. Specifically, the cylindrical lens 2 is placed 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 the bottom surface of the cylindrical lens 2 is parallel to the X-axis of the imaging plane of the charge-coupled image sensor 3. The normal vector of the imaging plane of the charge-coupled image sensor 3 is parallel to the imaging optical axis 4 of the objective lens 1. A standard 45-degree beam-splitting cube 5 is placed under the objective lens 1. The edge of the 45-degree beam-splitting surface 6 of the standard 45-degree beam-splitting cube 5 is parallel to the X-axis of the imaging plane of the charge-coupled image sensor 3. After the fluorescence beam is reflected or transmitted by the 45-degree beam-splitting surface 6 of the standard 45-degree beam-splitting cube, it enters the objective lens 1 and is received by the charge-coupled image sensor 3 after passing through the cylindrical lens 2. The fluorescence excitation light source 7 is placed on the mirror side at an angle of 45 degrees to the 45-degree beam-splitting surface 6. The coordinate value of the intersection point of the imaging optical axis 4 of the objective lens and the imaging plane of the charge-coupled image sensor 3 in the plane coordinate system of its imaging plane is ( x o , y o ), and the imaging optical axis 4 of the objective lens 1 passes through the center point of the 45-degree beam-splitting surface 6 of the standard 45-degree beam-splitting cube 5. The distance between the focal longitudinal object plane 14 (the object plane perpendicular to the imaging optical axis at the focal point) of the microscope 8 and the center point of the 45-degree beam-splitting surface 6 is D.

[0060] As an example, the microscope 8 can be a fluorescence microscope.

[0061] In step S2, please refer to Figure 4 in step S2, set up the microscope, fluorescent microspheres, planar substrate, and the first displacement stage so that the fluorescent microspheres are imaged on the charge-coupled image sensor.

[0062] As an example, a sub-millimeter fluorescent microsphere 9 is fixed on a planar substrate 10, and then the substrate 10 is fixedly mounted parallel on a six-axis precision calibration displacement stage 11. The six-axis precision calibration displacement stage 11 with the substrate 10 is placed at the lower end of the beam incident surface 12 at the bottom of the standard 45-degree beam-splitting cube 5 of the microscope 8 with an astigmatic imaging function. After turning on the fluorescence excitation light source 7, the light beam of the light source is reflected by the standard 45-degree beam-splitting cube 5 and irradiates the fluorescent microsphere 9, causing it to emit fluorescence. After passing through the standard 45-degree beam-splitting cube 5, the fluorescent microsphere 9 can be imaged on the charge-coupled image sensor 3.

[0063] In step S3, please refer to Figure 4In step S3, the six-dimensional precision calibration displacement stage is made to perform translational motions in two non-parallel directions, obtaining the ratios of the widths of three XY axes corresponding to three images before and after the movement of the fluorescent microsphere on the charge-coupled image sensor, and determining the attitude vector of the six-dimensional precision calibration displacement stage corresponding to the situation when the ratios of the widths of the three XY axes are the same before and after the movement.

[0064] As an example, in addition to obtaining the imaging centroid position by fitting the imaging light intensity of the fluorescent microsphere 9 with a two-dimensional Gaussian function, the width values of the imaging light intensity distribution 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 ratio of the fluorescent microsphere 9 can be obtained. The XY-axis width ratio includes: the width ratio in the X-axis direction and the width ratio in the Y-axis direction. On different longitudinal object planes (object planes perpendicular to the imaging optical axis), due to the astigmatic imaging effect of the cylindrical lens 2, the XY-axis width ratio of the fluorescent microsphere 9 is different.

[0065] As an example, the six-dimensional precision calibration displacement stage 11 is made to perform translational motions in two non-parallel directions, obtaining the ratios of the widths of three XY axes corresponding to three images before and after the movement of the fluorescent microsphere 9 on the charge-coupled image sensor 3. 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. Traverse the pitch attitude and yaw attitude of the six-dimensional precision calibration displacement stage 11 with the smallest step size. In each attitude case, perform the above translational motion and obtain the corresponding ratios of the widths of the three XY axes, and determine from them an attitude vector of the six-dimensional precision calibration displacement stage 11 corresponding to the situation when the ratios of the widths of the three XY axes are the same before and after the movement ( m , n , q ), that is, the vector value in the self-motion coordinate system of the six-dimensional precision calibration displacement stage.

[0066] As an example, the attitude vector ( m , n , q ) is the normal vector of a longitudinal object plane of the determined fluorescence microscope and is also the vector of the imaging optical axis 4.

[0067] In step S4, please refer to Figure 4 In step S4, the six-dimensional precision calibration displacement stage is made to move back and forth along the direction of the attitude vector, and it is ensured that the fluorescent microsphere can be imaged on the charge-coupled image sensor, obtaining the functional relationship between the height of the different longitudinal object planes and the XY-axis width ratio of the fluorescent microsphere, that is, the longitudinal object plane height function; on each longitudinal object plane, the six-dimensional precision calibration displacement stage is translated by an actual displacement value, and the measured displacement value corresponding to the imaging of the fluorescent microsphere on the charge-coupled image sensor is determined. According to the actual displacement value and the measured displacement value, the microscopic magnification function is obtained.

[0068] As an example, the six-dimensional precision calibration displacement stage 11 is moved back and forth along the attitude vector ( m , n , q ), and it is ensured that the fluorescent microsphere 9 can be imaged on the charge-coupled image sensor 3, so as to obtain the functional relationship between the ratio of the longitudinal object plane height (relative to the longitudinal object plane of the focus) and the XY-axis width of the fluorescent microsphere 9, that is, the longitudinal object plane height function f ( w ), where w is the variable of the XY-axis width ratio of the fluorescent microsphere 9.

[0069] As an example, on each longitudinal object plane, the six-dimensional precision calibration displacement stage 11 is translated by an actual displacement value, and the measured displacement value of the fluorescent microsphere 9 is obtained on the charge-coupled image sensor 3. The measured displacement value of the fluorescent microsphere 9 is divided by the actual displacement value of the six-dimensional precision calibration displacement stage 11 to obtain the microscopic magnification value on each longitudinal object plane.

[0070] As an example, when the longitudinal object plane height is different, the microscopic magnification values are also different. Then, the microscopic magnification value can be a function value related to the longitudinal object plane height or the XY-axis width ratio. The microscopic magnification function is N ( w ), where w is the variable of the XY-axis width ratio of the fluorescent microsphere 9. Since the standard 45-degree beam splitting cube 5 has a mirror symmetry effect, the longitudinal object plane height function f ( w ) and the microscopic magnification function N ( w ) corresponding to the beam incident surface 13 on the side of the standard 45-degree beam splitting cube 5 can be obtained.

[0071] In step S5, please refer to Figure 4 in step S5, fix the first gear and the second gear on the first rotating shaft and the second rotating shaft of the upper turntable respectively, and fix a bracket with a gear transmission shaft on one side on the tabletop of the lower turntable.

[0072] As an example, please refer to Figure 3 , fix the first gear and the second gear on the first side rotating shaft 18 and the second rotating shaft 19 of the upper turntable of the laser tracker respectively, and fix a bracket 26 with a gear transmission shaft 25 on one side on the tabletop of the lower turntable 16 of the laser tracker.

[0073] As an example, when the lower turntable 16 rotates, it can drive the upper turntable 15 to rotate and also drive the bracket 26 to rotate. The bracket 26 is fixed to the gear transmission shaft 25 through a bearing, and both ends of the gear transmission shaft 25 are engaged with the first gear 23 and the second gear 24 of the upper turntable 15 respectively. When the first rotating shaft 18 of the upper turntable 15 rotates, the driving force can be transmitted to the gear transmission shaft 25 through the motor-side gear 23, causing the gear transmission shaft 25 to rotate, and then driving the second gear 24 to rotate, thereby causing the second-side rotating shaft 19 to rotate.

[0074] As an example, the first gear 23 can be a motor-side gear, and the second gear 24 can be an encoder-side gear.

[0075] As an example, the first rotating shaft 18 can be a motor-side rotating shaft, and the second rotating shaft 19 can be an encoder-side rotating shaft.

[0076] In step S6, please refer to Figure 4 step S6 in, fix the microscope on a six-dimensional precision adjustment displacement stage, fix the substrate with fluorescent microspheres on the tabletop of a micro translation adjustment stage, and fix the micro translation adjustment stage on the upper turntable, the first rotating shaft, the second rotating shaft, and the lower turntable rotating shaft in sequence.

[0077] As an example, please refer to Figure 3 , fix the microscope 8 with an astigmatic imaging function on a six-dimensional precision adjustment displacement stage 28, fix the substrate 10 with fluorescent microspheres 9 on the tabletop of a micro translation adjustment stage 29, and the micro translation adjustment stage 29 can finely adjust the spatial position of the fluorescent microspheres 9. Fix the micro translation adjustment stage 29 on the first rotating shaft 18 of the upper turntable 15, the second rotating shaft 19, and the lower turntable rotating shaft 17 in sequence.

[0078] As an example, after the micro translation adjustment stage 29 is fixed each time, start the upper turntable motor or the lower turntable motor to make the corresponding rotating shaft rotate one circle, ensuring that the fluorescent microspheres 9 can be imaged by the microscope 8 during the one-circle rotation of the rotating shaft. The Gaussian fitting centroid coordinate values of the imaging change in the plane coordinates of the imaging surface of the charge-coupled image sensor 3, that is, it is necessary to ensure that the fluorescent microspheres 9 are not exactly on the rotation axis, and ensure that the microscope 8 with an astigmatic imaging function will not be touched by any object during the rotation of the upper turntable 15 and the lower turntable 16.

[0079] As an example, when the lower turntable rotates for imaging, the bottom light beam incident surface 12 of the standard 45-degree beam splitting cube 5 receives fluorescence; when the upper turntable 15 rotates for imaging, the side light beam incident surface 13 of the standard 45-degree beam splitting cube 5 receives fluorescence.

[0080] In step S7, please refer to Figure 4In step S7, the micro translation adjustment stage with fluorescent microspheres and the substrate is fixed on the rotating shaft of the lower turntable. The lower turntable motor is started, and after the rotating shaft of the lower turntable rotates by a minimum step angle and then stops, the imaging of the fluorescent microspheres by the microscope is recorded. The centroid coordinates and the XY-axis width ratio in the imaging plane coordinates of the charge-coupled image sensor are determined through a two-dimensional Gaussian function. According to the XY-axis width ratio, the microscopic magnification corresponding to the longitudinal object plane height where the fluorescent microspheres are located is determined. According to the centroid coordinates and the microscopic magnification, the spatial coordinate values of the fluorescent microspheres mapped to the imaging plane coordinates of the charge-coupled image sensor are determined.

[0081] As an example, the micro translation adjustment stage 29 with fluorescent microspheres 9 and the substrate 10 is fixed on the rotating shaft 17 of the lower turntable again. The lower turntable motor is started, and after the rotating shaft 17 of the lower turntable rotates by a minimum step angle and then stops, the imaging of the fluorescent microspheres 9 by the microscope 8 with astigmatic imaging function is recorded. The centroid coordinates and the XY-axis width ratio in the imaging plane coordinates of the charge-coupled image sensor 3 are obtained by fitting the imaging light intensity through a two-dimensional Gaussian function. The microscopic magnification function corresponding to the longitudinal object plane height where the fluorescent microspheres 9 are located at this time can be determined through the XY-axis width ratio N ( w ) of the microscopic magnification. Divide the centroid coordinates by the microscopic magnification to obtain the spatial coordinate values of the fluorescent microspheres 9 mapped to the imaging plane coordinates of the charge-coupled image sensor 3.

[0082] As an example, when the lower turntable 16 rotates one circle, a corresponding series of spatial coordinate values of the fluorescent microspheres 9 can be obtained. These spatial coordinate values of the fluorescent microspheres 9 are subjected to plane ellipse function fitting to obtain the plane mapping spatial trajectory drawn by the rotating shaft passing through the fluorescent microspheres 9. Record the length values of the major and minor axes of the fitting ellipse at this time, and traverse the pitching and yaw postures of the six-dimensional precision adjustment displacement stage 28 with the minimum step size. A length value of the major and minor axes of a fitting ellipse can be obtained for each posture.

[0083] As an example, when the major axis and the minor axis of the fitting ellipse corresponding to a certain posture are the minimum values in all traversed postures, that is, when the rotation axis is perpendicular to the imaging plane, the length of the spatial plane trajectory of the mapped imaging is the shortest. At this time, the rotation axis 20 of the lower turntable is parallel to the imaging optical axis 4 of the microscope 8.

[0084] As an example, the plane ellipse function fitting can adopt a general ellipse function where the major and minor axes of the ellipse are not parallel to the coordinate axes.

[0085] In step S8, please refer to Figure 4 In step S8, a first reference coordinate system is constructed according to the spatial coordinate values. In the first reference coordinate system, the spatial straight line equation of the rotation axis of the lower turntable is determined, and the radial runout value within a complete rotation period of the rotating shaft of the lower turntable is obtained.

[0086] As an example, in the case where the rotation axis 20 of the lower turntable is parallel to the imaging optical axis 4 of the microscope 8, on the premise of obtaining the imaging light intensity of the fluorescent microspheres 9 corresponding to all the step rotations of the lower turntable and the coordinate values of the imaging plane of the charge-coupled image sensor 3, the centroid coordinates and the XY-axis width ratio are obtained under the coordinate values of the imaging plane of the charge-coupled image sensor 3 by fitting the imaging light intensity with a two-dimensional Gaussian. The corresponding longitudinal object plane height value and the microscopic magnification are obtained through the XY-axis width ratio, and the centroid coordinates are divided by the microscopic magnification to obtain the spatial coordinate values of the fluorescent microspheres 9 mapped to the coordinate values of the imaging plane of the charge-coupled image sensor 3. Let the central coordinates obtained by fitting these spatial coordinate values with a spatial ellipse function be ( x 拟 , y 拟 ). Translate the origin of the coordinate system of the imaging plane of the charge-coupled image sensor 3 to the intersection coordinate of the imaging optical axis 4 of the microscope and the imaging plane of the charge-coupled image sensor 3 ( x o , y o ), and then translate it along the direction of the imaging optical axis 4 to the focal longitudinal object plane 14. The corresponding coordinate system is denoted as the first reference coordinate system X 基 Y 基 Z 基 . The first reference coordinate system is the measurement coordinate system of the microscope 8 at this time.

[0087] Further, subtract the intersection coordinate ( x o , y o ) from the spatial coordinate values of the fluorescent microspheres 9 mapped to the coordinate values of the imaging plane of the charge-coupled image sensor 3 to obtain the XY-axis plane coordinate values of the fluorescent microspheres 9 in the first reference coordinate system X 基 Y 基 Z 基 . The obtained longitudinal object plane height value is the Z-axis coordinate value in the first reference coordinate system X 基 Y 基 Z 基 . Thus, the rotation axis 20 of the lower turntable can be obtained as the spatial straight line equation passing through the point ( 基 Y 基 Z 基 ( x 拟 - x o , y 拟 - y o , 0) and with the direction of (0, 0, 1) in the first reference coordinate system X

[0088] As an example, in the first reference coordinate system X 基 Y 基 Z 基 within one complete rotation period of the lower turntable rotating shaft 17, all the axial runout values can be the difference between the Z-axis value of the fluorescent microsphere 9 corresponding to each rotation step angle of the lower turntable rotating shaft 17 and the Z-axis value of the fluorescent microsphere 9 at the moment when it does not rotate. The radial runout value within one complete rotation period of the lower turntable rotating shaft 17 can be the difference between the distance from the XY-axis plane coordinates of the fluorescent microsphere 9 corresponding to each rotation step angle of the lower turntable rotating shaft 17 to the origin and the distance from the coordinate point on the fitting plane ellipse function corresponding to this rotation step angle to the origin.

[0089] In step S9, refer to Figure 4 step S9 in it, set the lower turntable rotating shaft 17 to be stationary, record the spatial coordinate values of the fluorescent microsphere at this time in the first reference coordinate system, construct the moving coordinate system of the six-dimensional precision adjustment displacement stage, determine the first vector value of the unit vector on the X-axis of the moving coordinate system in the first reference coordinate system, determine the first coordinate value of the origin of the moving coordinate system in the first reference coordinate system, rotate the six-dimensional precision adjustment displacement stage by a first angle around the X-axis of the moving coordinate system, and rotate the unit vector in the first reference coordinate system by the first angle around the first vector value to obtain a second vector value.

[0090] As an example, ensure that the lower turntable rotating shaft 17 is stationary, and record the spatial coordinate values of the fluorescent microsphere 9 at this time in the first reference coordinate system X 基 Y 基 Z 基 . . Construct the moving coordinate system X 调 Y 调 Z 调 of the six-dimensional precision adjustment displacement stage 28. Assume that the first vector value of the unit vector on the X-axis of the moving coordinate system X 调 Y 调 Z 调 of the six-dimensional precision adjustment displacement stage 28 in the first reference coordinate system X 基 Y 基 Z 基 is ( u X , u Y ,u Z ), and the first coordinate value of the origin of the moving coordinate system X 调 Y 调 Z 调 in the first reference coordinate system X 基 Y 基 Z 基 is ( o X , oY ,o Z ), causing the six - dimensional precision adjustment displacement stage 28 to rotate a small first angle about the X - axis of the moving coordinate system 调 Y 调 Z 调 by a small first angle about the X - axis of the moving coordinate system θ , that is, rotating by a first angle about the first vector value ( 基 Y 基 Z 基 in the moving coordinate system X u X , u Y ,u Z ). Rotate the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) in the first reference coordinate system X θ . Rotate the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) in the first reference coordinate system X 基 Y 基 Z 基 by a first angle about the first vector value ( u X , u Y ,u Z ). θ .

[0091] As an example, subtract the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) in the first reference coordinate system X 基 Y 基 Z 基 from the first coordinate value ( o X , o Y ,o Z ), and then right - multiply by the first rotation transformation matrix respectively to obtain the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) rotated by a first angle about the first vector value ( u X , u Y ,u Z ) in the first reference coordinate system X θ . The corresponding second vector values in the first reference coordinate system X 基 Y 基 Z 基 .

[0092] As an example, the expression of the first rotation transformation matrix is: where u X ,u Y , u Z are respectively the X-axis, Y-axis, and Z-axis values of the first vector value, θ is the first angle.

[0093] As an example, the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) in the first reference coordinate system X 基 Y 基 Z 基 are subtracted from the first coordinate values ( o X , o Y ,o Z ) to obtain (1 - o X , - o Y , - o Z ), (- o X , 1 - o Y , - o Z ), and (- o X , - o Y , 1 - o Z ). Then, after right-multiplying by the first rotation transformation matrix respectively, the second vector values are obtained. Then, the second vector values are added to the first coordinate values ( o X , o Y ,o Z ) respectively to obtain ( i x , i y , i z ), ( j x , j y , j z ), and ( k x , k y , k z ). The origin coordinates (0, 0, 0) and the first coordinate values ( oX , o Y ,o Z ), subtract, then multiply on the right by the first rotation transformation matrix, and then add to the first coordinate value ( o X , o Y ,o Z ) to obtain ( t x , t y , t z ). Then, in the first reference coordinate system X 基 Y 基 Z 基 , the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) rotate around the first vector value ( u X , u Y ,u Z ) by the first angle θ and the second vector values in the first reference coordinate system X 基 Y 基 Z 基 are respectively ( i x - t x , i y - t y , i z - t z ), ( j x - t x , j y - t y , j z - t z ) and ( k x - t x , k y - t y , k z - t z ). In step S10, refer to Figure 4 step S10 in

[0094] As an example, the six-axis precision adjustment stage 28 rotates around the X-axis of the moving coordinate system by the first small angle 调 Y 调 Z 调 . θ , driving the microscope 8 to also rotate around the X-axis of the moving coordinate system by the first small angle 调 Y 调 Z 调 . θ . At this time, the first reference coordinate system X 基 Y 基 Z 基 also rotates around the X-axis of the moving coordinate system by the first small angle 调 Y 调 Z 调 , obtaining the measurement coordinate system X θ of the microscope 8 θ Y θ Z θ .

[0095] As an example, similar to the case where the first reference coordinate system X 基 Y 基 Z 基 is the measurement coordinate system of the microscope 8 in step S8, the spatial coordinate values of the fluorescent microsphere 9 in the measurement coordinate system X θ Y θ Z θ of the microscope 8 can be obtained ( x θ , y θ , z θ ). Thus, the spatial coordinate relationship of the fluorescent microsphere 9 before and after the rotation of the six-axis precision adjustment stage 28 can be obtained, and the expression is as follows: wherein, ( x θ , y θ , z θ ) are the spatial coordinates of the fluorescent microsphere 9 in the measurement coordinate system X θ Y θ Z θSpatial coordinate values in; ( i x - t x , i y - t y , i z - t z ), ( j x - t x , j y - t y , j z - t z ) and ( k x - t x , k y - t y , k z - t z ) are respectively the unit vectors (1, 0, 0), (0, 1, 0) and (0, 0, 1) in the first reference coordinate system X 基 Y 基 Z 基 after rotating by the first vector value ( u X , u Y ,u Z ) by the first angle θ in the first reference coordinate system X 基 Y 基 Z 基 ; is the spatial coordinate value of the fluorescent microsphere 9 in the first reference coordinate system X 基 Y 基 Z 基 when the lower turntable rotating shaft 17 is stationary.

[0096] In step S11, please refer to Figure 4In step S11, rotate the six-dimensional precision adjustment displacement stage back to the starting attitude, determine the third vector value of the unit vector on the Y-axis of the motion coordinate system of the six-dimensional precision adjustment displacement stage in the first reference coordinate system, rotate the six-dimensional precision adjustment displacement stage around the Y-axis of the motion coordinate system by a second angle, obtain the spatial coordinate relationship of the fluorescent microspheres before and after the six-dimensional precision adjustment displacement stage rotates by the second angle, and obtain the first vector value, the first coordinate value, and the third vector value through the least squares method.

[0097] As an example, rotate the six-dimensional precision adjustment displacement stage 28 back to the starting attitude of step S9. Assume that the motion coordinate system of the six-dimensional precision adjustment displacement stage 28 is X 调 Y 调 Z 调 The third vector value of the unit vector on the Y-axis in the first reference coordinate system X 基 Y 基 Z 基 is ( v X , v Y ,v Z ), and rotate the six-dimensional precision adjustment displacement stage 28 around the Y-axis of the motion coordinate system X 调 Y 调 Z 调 by a small second angle δ .

[0098] As an example, similarly, a spatial coordinate relationship of the fluorescent microspheres 9 before and after the rotation of the six-dimensional precision adjustment displacement stage 28 similar to the expression (II) can also be obtained. Thus, six relationships about nine unknowns are obtained, namely the first vector value ( u X , u Y ,u Z ), the first coordinate value ( o X , o Y ,o Z ), and the six relationships of the third vector value ( v X , v Y ,v Z ).

[0099] Furthermore, repeat steps S9 to S11, rotating more different first angles θ and second angles δ, so that more relationships than the number of nine unknowns can be obtained, enabling the construction of an overdetermined system of equations, and the first vector value ( u X , u Y ,u Z ), the first coordinate value ( o X , o Y ,o Z ), and the third vector value ( v X , v Y ,v Z ) can be calculated by the least squares method.

[0100] In step S12, refer to step S12 in Figure 4 . Fix the micro translation adjustment stage with fluorescent microspheres and the substrate on the first rotating shaft of the upper turntable, start the motor of the upper turntable to control the rotation of the first rotating shaft, construct the second reference coordinate system, and determine the spatial straight line equation of the rotation axis on the motor side of the upper turntable in the second reference coordinate system to obtain the axial and radial runout values within a complete rotation period.

[0101] As an example, fix the micro translation adjustment stage 29 with fluorescent microspheres 9 and substrate 10 on the first rotating shaft 18 of the upper turntable 15, start the motor of the upper turntable 15 to control the rotation of the first rotating shaft 18, and the remaining operations are the same as in step S7 and step S8. At this time, the measurement coordinate system of the microscope 8 is X’ 基 Y’ 基 Z’ 基 , that is, the second reference coordinate system is X’ 基 Y’ 基 Z’ 基 .

[0102] As an example, since the imaging fluorescence of the fluorescent microspheres 9 is transmitted to the light beam incident surface 13 on the side of the standard 45-degree beam splitting cube 5 to form an image, due to the mirroring effect of the beam splitting surface 6 of the standard 45-degree beam splitting cube 5, the spatial coordinate values of the symmetric mirror image of the fluorescent microspheres 9 obtained are in the second reference coordinate system X’ 基 Y’ 基 Z’ 基 . These spatial coordinate values are uniformly expressed as ( x’ , y’, z’ ). Since the distance between the longitudinal object plane 14 of the focus of the microscope 8 and the center point of the 45-degree beam splitting surface 6 is known as D in step S1, the actual fluorescent microspheres 9 in the second reference coordinate system X’ 基 Y’基 Z’ 基 The spatial coordinate values in x’ , y’ -D ,z’ +D), similar to step S8, in the second reference coordinate system X’ 基 Y’ 基 Z’ 基 , the spatial straight-line equation of the rotation axis 21 on the motor side of the upper turntable 15 and the axial and radial runout values within a complete rotation period can be obtained.

[0103] In step S13, refer to Figure 4 step S13 in , determine the yaw angle and pitch angle of the second reference coordinate system relative to the first reference coordinate system according to the six-dimensional precision adjustment displacement stage, rotate the unit vector in the first reference coordinate system by the yaw angle and pitch angle to obtain the spatial coordinate values of the fluorescent microsphere in the first reference coordinate system from its spatial coordinates in the second reference coordinate system, and convert the spatial straight-line equation of the rotation axis of the upper turntable into the spatial straight-line equation in the first coordinate system.

[0104] As an example, since the second reference coordinate system X’ 基 Y’ 基 Z’ 基 is also determined by the principle that the spatial plane trajectory length is the shortest when the rotation axis is perpendicular to the imaging plane, so the second reference coordinate system X’ 基 Y’ 基 Z’ 基 and the first reference coordinate system X 基 Y 基 Z 基 will have an attitude difference, and the attitude difference is due to the attitude of the six-dimensional precision adjustment displacement stage 28 corresponding to the first reference coordinate system X 基 Y 基 Z 基 and the attitude of the six-dimensional precision adjustment displacement stage 28 corresponding to the second reference coordinate system X’ 基 Y’ 基 Z’ 基 having a yaw angle θ’ (i.e., rotating around the X-axis of the moving coordinate system X 调 Y 调 Z 调 ) and a pitch angle δ’ (i.e., rotating around the Y-axis of the moving coordinate system X 调 Y 调 Z 调 ).

[0105] As an example, the yaw angle and pitch angle can be determined by the six-dimensional precision adjustment displacement stage 28. Denote the first reference coordinate system X 基 Y 基 Z基 Yaw θ’ and pitch δ’ After the angle becomes the second reference coordinate system X’ 基 Y’ 基 Z’ 基 , the corresponding second rotation transformation matrix to be right - multiplied is: Among them, θ’ is the yaw angle, δ’ is the pitch angle, ([[]] u X , u Y ,u Z ) is the first vector value of the unit vector on the X - axis of the moving coordinate system X 调 Y 调 Z 调 of the six - dimensional precision adjustment stage 28 in the first reference coordinate system X 基 Y 基 Z 基 ), ( v X , v Y ,v Z ) is the third vector value of the unit vector on the Y - axis of the moving coordinate system X 调 Y 调 Z 调 of the six - dimensional precision adjustment stage 28 in the first reference coordinate system X 基 Y 基 Z 基 .

[0106] As an example, all are known quantities in the second rotation transformation matrix. Through the second rotation transformation matrix and the origin of the moving coordinate system X 调 Y 调 Z 调 in the first reference coordinate system X 基 Y 基 Z 基 ), the first coordinate value ( o X , o Y ,o Z ). Similar to the operation in step S9, convert the unit vectors (1, 0, 0), (0, 1, 0), (0, 0, 1) and the origin (0, 0, 0) in the first reference coordinate system X 基 Y 基 Z 基 to ( i' x , i'y , i' z ),( j' x , j' y , j' z ),( k' x , k' y , k' z ), and ( t' x , t' y , t' z ), so that the first reference coordinate system X 基 Y 基 Z 基 The unit vectors (1, 0, 0), (0, 1, 0) and (0, 0, 1) in are yawed θ’ and pitched δ’ by an angle, and in the first reference coordinate system X 基 Y 基 Z 基 they become ( i' x - t' x , i' y - t' y , i' z - t' z ),( j' x - t' x , j' y - t' y , j' z - t' z ), and ( k' x - t' x , k' y - t' y , k' z - t' z ), and thus the fluorescent microsphere 9 in the second reference coordinate system X’ 基 Y’基 Z’ 基 The spatial coordinates in x’ , y’ -D ,z’ +D) are corresponding to the spatial coordinate values in the first reference coordinate system X 基 Y 基 Z 基 . The expression is: x’ 基 , y’ 基 , z’ 基 ), and the expression is: As an example, for any two coordinate values on the spatial straight line equation of the rotation axis 21 on the motor side of the upper turntable 15 in the second reference coordinate system X’ 基 Y’ 基 Z’ 基 , after being converted by the expression (IV), the coordinate values in the first reference coordinate system X 基 Y 基 Z 基 can be obtained, so as to determine the spatial straight line equation in the first reference coordinate system X 基 Y 基 Z 基 , that is, to determine the spatial straight line equations of the rotation axis 20 of the lower turntable and the rotation axis 21 on the motor side of the upper turntable in the same coordinate system.

[0107] In step S14, please refer to Figure 4 in step S14, fix the micro translation adjustment stage with fluorescent microspheres and the substrate on the second rotating shaft of the upper turntable, and start the lower turntable motor, rotate 180 degrees to symmetrically interchange the positions of the encoder side and the motor side of the upper turntable, obtain the axial and radial runout values within a complete rotation period, determine the spatial straight line equations of the rotation axis of the lower turntable and the rotation axis on the encoder side of the upper turntable in the first reference coordinate system, and realize the determination of the spatial straight line equations of the rotation axis of the lower turntable, the rotation axis on the motor side of the upper turntable, and the rotation axis on the encoder side of the upper turntable in the same reference coordinate system and the error detection within a complete rotation period.

[0108] As an example, fix the micro translation adjustment stage 29 with fluorescent microspheres 9 and the substrate 10 on the second rotating shaft 19 of the upper turntable 15, and start the lower turntable motor, rotate 180 degrees to symmetrically interchange the positions of the encoder side and the motor side of the upper turntable 15. Similar to step S12 and step S13, obtain the axial and radial runout values within a complete rotation period.

[0109] Furthermore, in the first reference coordinate system X 基 Y 基 Z基 Determine the spatial straight-line equations of the rotation axis 20 of the lower turntable and the rotation axis 22 on the encoder side of the upper turntable 15. Thus, the error detection of the rotation axis 20 of the lower turntable, the rotation axis 21 on the motor side of the upper turntable 15, and the rotation axis 22 on the encoder side within a complete rotation cycle is achieved, and the spatial straight-line equations of the rotation axis 20 of the lower turntable, the rotation axis 21 on the motor side of the upper turntable 15, and the rotation axis 22 on the encoder side in the same first reference coordinate system X 基 Y 基 Z 基 are determined.

[0110] In the method for detecting the rotation axis error of the turntable of the upper shaft type laser tracker connected by the overall measurement optical path of the present application, the astigmatism effect is introduced through a cylindrical lens, and the functional relationships between the width ratio of the XY axis of the fluorescence microsphere imaging and the height of the longitudinal object surface, and the microscopic magnification function between the actual displacement and the measured displacement are established, providing an accurate measurement basis for subsequent error detection; during the detection of the rotation axis error of the turntable, by fixing the fluorescence microsphere substrate on the rotation axis of the lower turntable, the motor side and the encoder side rotation axis of the upper turntable respectively, combined with the construction of multi-coordinate system conversion and spatial straight-line equations, error parameters such as the radial runout value and axial runout value of each rotation axis can be comprehensively detected; through the rotation and coordinate system conversion of the six-dimensional precision adjustment displacement stage, the detection of the rotation axis error on the motor side and the encoder side of the upper turntable in the same reference coordinate system is realized, eliminating the errors caused by different measurement references, and improving the accuracy and comparability of the detection results; through data processing means such as the least squares method, the measurement results are further optimized, and various errors of the turntable rotation axis within a complete rotation cycle can be effectively detected; by setting a gear drive shaft between the upper and lower turntables, the synchronous drive of the motor side and the encoder side of the upper turntable is realized, providing a stable motion basis for the rotation axis error detection; by utilizing the mirror symmetry effect of the standard 45-degree beam splitting cube, the optical path design is simplified, and the stability and reliability of the system are improved. The method for detecting the rotation axis error of the turntable of the upper shaft type laser tracker connected by the overall measurement optical path of the present application provides reliable technical support for the high-precision manufacturing and calibration of the turntable of the laser tracker, and makes necessary technical preparations for realizing the error compensation of the rotation axis of the turntable of the upper shaft type laser tracker connected by the overall measurement optical path and improving the tracking accuracy and stability of the laser tracker.

[0111] It should be understood that although the steps in the flowcharts of the accompanying drawings are shown sequentially as indicated by the arrows, these steps are not necessarily executed sequentially in the order indicated by the arrows. Unless otherwise clearly stated herein, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, at least a part of the steps in the accompanying drawings may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or sub-steps or stages of other steps.

[0112] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered that the scope described in this specification is covered.

[0113] Although this application has been disclosed above with embodiments, it is not intended to limit this application. Any person with ordinary knowledge in the technical field to which this application pertains may make some modifications and refinements without departing from the spirit and scope of this application. Therefore, the protection scope of this application shall be subject to that defined by the appended patent application scope.

Claims

1. A method for detecting the axis error of the turntable of a rotary-axis laser tracker in the overall measurement optical path connection, characterized in that, Including the following steps: Step S1: Construct a microscope using an objective lens, a cylindrical lens, a charge-coupled image sensor, a standard 45-degree beam-splitting cube mirror, and a fluorescence excitation light source; Step S2: Set up the microscope, fluorescent microspheres, substrate, and six-axis precision calibration displacement stage so that the fluorescent microspheres are imaged on the charge-coupled image sensor; Step S3: Make the six-axis precision calibration displacement stage perform two translational motions with non-parallel motion directions to obtain the three XY-axis width ratios corresponding to the three images of the fluorescent microspheres before and after movement on the charge-coupled image sensor, and determine the attitude vector of the six-axis precision calibration displacement stage when the three XY-axis width ratios are the same before and after movement; Step S4: Make the six-axis precision calibration displacement stage move back and forth along the direction of the attitude vector and ensure that the fluorescent microspheres can be imaged on the charge-coupled image sensor to obtain the functional relationship between the longitudinal object plane height and the XY-axis width ratio of the fluorescent microspheres, that is, the longitudinal object plane height function; On each longitudinal object plane, translate the six-axis precision calibration displacement stage by an actual displacement value, determine the measured displacement value of the corresponding fluorescent microspheres imaged on the charge-coupled image sensor, and obtain the microscopic magnification function according to the actual displacement value and the measured displacement value; Step S5: Fix the first gear and the second gear on the first rotating shaft and the second rotating shaft of the upper turntable respectively, and fix a bracket with a gear transmission shaft on one side on the tabletop of the lower turntable; Step S6: Fix the microscope on a six-axis precision adjustment displacement stage, fix the substrate with fluorescent microspheres on the tabletop of a micro translation adjustment stage, and fix the micro translation adjustment stage on the upper turntable, the first rotating shaft, the second rotating shaft, and the lower turntable rotating shaft in sequence; Step S7: Fix the micro translation adjustment stage with fluorescent microspheres and substrate on the lower turntable rotating shaft, start the lower turntable motor, make the lower turntable rotating shaft rotate a minimum step angle and then stop, record the image of the fluorescent microspheres by the microscope, determine the centroid coordinates and the XY-axis width ratio in the imaging plane coordinates of the charge-coupled image sensor through a two-dimensional Gaussian function, determine the microscopic magnification corresponding to the longitudinal object plane height where the fluorescent microspheres are located according to the XY-axis width ratio, and determine the spatial coordinate value of the fluorescent microspheres mapped to the imaging plane coordinates of the charge-coupled image sensor according to the centroid coordinates and the microscopic magnification; Step S8: Construct a first reference coordinate system according to the spatial coordinate values, determine the spatial straight line equation of the lower turntable rotation axis in the first reference coordinate system, and obtain the radial runout value within a complete rotation period of the lower turntable rotating shaft; Step S9: Set the rotation axis of the lower turntable stationary, record the spatial coordinate values of the fluorescent microspheres in the first reference coordinate system, construct the motion coordinate system of the six-dimensional precision adjustment displacement stage, determine the first vector value of the unit vector on the X-axis of the motion coordinate system in the first reference coordinate system, determine the first coordinate value of the origin of the motion coordinate system in the first reference coordinate system, rotate the six-dimensional precision adjustment displacement stage by a first angle around the X-axis of the motion coordinate system, and rotate the unit vector in the first reference coordinate system by the first angle around the first vector value to obtain a second vector value; Step S10: Rotate the first reference coordinate system by the first angle around the X-axis of the motion coordinate system to obtain the measurement coordinate system of the microscope, determine the spatial coordinate values of the fluorescent microspheres in the measurement coordinate system, and obtain the spatial coordinate relationship of the fluorescent microspheres before and after the six-dimensional precision adjustment displacement stage rotates by the first angle; Step S11: Rotate the six-dimensional precision adjustment displacement stage back to the starting position, determine the third vector value of the unit vector on the Y-axis of the motion coordinate system of the six-dimensional precision adjustment displacement stage in the first reference coordinate system, rotate the six-dimensional precision adjustment displacement stage by a second angle around the Y-axis of the motion coordinate system, obtain the spatial coordinate relationship of the fluorescent microspheres before and after the six-dimensional precision adjustment displacement stage rotates by the second angle, and obtain the first vector value, the first coordinate value, and the third vector value by the least squares method; Step S13: According to the six-dimensional precision adjustment displacement stage, determine the yaw angle and pitch angle of the second reference coordinate system relative to the first reference coordinate system, rotate the unit vector in the first reference coordinate system by the yaw angle and pitch angle to obtain the spatial coordinate value of the fluorescent microspheres in the second reference coordinate system in the first reference coordinate system, and convert the spatial straight line equation of the rotation axis of the upper turntable into the spatial straight line equation in the first coordinate system; Step S14: Fix the micro translation adjustment stage with the fluorescent microspheres and the substrate on the first rotation axis of the upper turntable, start the motor of the upper turntable to control the rotation of the first rotation axis, construct the second reference coordinate system, determine the spatial straight line equation of the rotation axis on the motor side of the upper turntable in the second reference coordinate system, and obtain the axial and radial runout values within a complete rotation period; Step S15: Fix the micro translation adjustment stage with the fluorescent microspheres and the substrate on the second rotation axis of the upper turntable, and start the motor of the lower turntable. Rotate 180 degrees to symmetrically interchange the positions of the encoder side and the motor side of the upper turntable to obtain the axial and radial runout values within a complete rotation period. Determine the spatial straight line equations of the rotation axis of the lower turntable and the rotation axis of the encoder side of the upper turntable in the first reference coordinate system, and realize the determination of the spatial straight line equations of the rotation axis of the lower turntable, the rotation axis on the motor side of the upper turntable, and the rotation axis of the encoder side of the upper turntable in the same reference coordinate system and the error detection within a complete rotation period.

2. The method for detecting the rotational shaft error of the rotary table of the upper shaft type laser tracker by connecting the overall measurement optical path according to claim 1, characterized in that Construct a microscope using an objective lens, a cylindrical lens, a charge-coupled image sensor, a standard 45-degree beam-splitting cube mirror block, and a fluorescence excitation light source, including: Place a 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. The edge where the semi-circular section of the cylindrical lens intersects the bottom surface of the cylindrical lens is parallel to the X-axis of the imaging plane of the charge-coupled image sensor. The normal vector of the imaging plane of the charge-coupled image sensor is parallel to the imaging optical axis of the objective lens. Place a standard 45-degree beam-splitting cube under the objective lens. The standard 45-degree beam-splitting cube includes a beam-splitting surface. The edge of the beam-splitting surface is parallel to the X-axis of the imaging plane of the charge-coupled image sensor. After passing through the beam-splitting surface, the fluorescence beam enters the objective lens, passes through the cylindrical lens, and is received by the charge-coupled image sensor. Place a fluorescence excitation light source on the mirror side that forms a 45-degree angle with the beam-splitting surface. The objective lens, the charge-coupled image sensor, the cylindrical lens, the standard 45-degree beam-splitting cube, and the fluorescence excitation light source form a microscope. The coordinate value of the intersection point of the imaging optical axis of the objective lens and the imaging plane of the charge-coupled image sensor in the plane coordinate system of its imaging plane is ( x o , y o ), and the imaging optical axis of the objective lens passes through the center point of the beam-splitting surface of the standard 45-degree beam-splitting cube. The distance between the longitudinal object plane of the focus of the microscope and the center point of the beam-splitting surface is D.

3. The method for detecting the rotational axis error of the rotary table of the upper rotating shaft type laser tracker by connecting the overall measurement optical path according to claim 1, wherein Set up the microscope, fluorescent microspheres, substrate, and six-dimensional precision calibration displacement stage to image the fluorescent microspheres on the charge-coupled image sensor, including: Fix a fluorescent microsphere on a substrate, and then fix the substrate parallel to a six-dimensional precision calibration displacement stage; place the six-dimensional precision calibration displacement stage with the substrate at the lower end of the light beam incident surface at the bottom of a standard 45-degree beam splitting cube under a microscope; after turning on the fluorescence excitation light source, the light beam of the light source is reflected by the standard 45-degree beam splitting cube and then irradiates the fluorescent microsphere, causing the fluorescent microsphere to emit fluorescence. After being transmitted by the standard 45-degree beam splitting cube, the fluorescent microsphere is imaged on the charge-coupled image sensor.

4. The method for detecting the spindle error of the rotary table of the upper spindle type laser tracker by connecting the overall measurement optical path according to claim 1, wherein Make the six-dimensional precision calibration displacement stage perform two translational motions with non-parallel motion directions, obtain the three XY-axis width ratios corresponding to three images of the fluorescent microsphere on the charge-coupled image sensor before and after the motion, and determine the attitude vector of the six-dimensional precision calibration displacement stage corresponding to the same three XY-axis width ratios before and after the motion, including: Make the six-dimensional precision calibration displacement stage perform two translational motions with non-parallel motion directions, obtain the three XY-axis width ratios corresponding to three images of the fluorescent microsphere on the charge-coupled image sensor before and after the motion. If the three XY-axis width ratios are the same, the plane determined by the two motion directions is a longitudinal object plane of a fluorescence microscope; traverse the pitch attitude and yaw attitude of the six-dimensional precision calibration displacement stage with the smallest step size. In each attitude case, perform the above translational motion and obtain the corresponding three XY-axis width ratios, and then determine the attitude vector of the six-dimensional precision calibration displacement stage corresponding to the same three XY-axis width ratios before and after the motion.

5. The method for detecting the spindle error of the rotary table of the upper shaft type laser tracker by connecting the overall measurement optical path according to claim 1, characterized in that Make the six-dimensional precision calibration displacement stage move back and forth along the direction of the attitude vector, and ensure that the fluorescent microsphere can be imaged on the charge-coupled image sensor, obtain the functional relationship between the height of the fluorescent microsphere at different longitudinal object planes and the XY-axis width ratio, that is, the longitudinal object plane height function; translate the six-dimensional precision calibration displacement stage by an actual displacement value on each longitudinal object plane, determine the measured displacement value of the corresponding fluorescent microsphere imaged on the charge-coupled image sensor, and obtain the microscopic magnification function according to the actual displacement value and the measured displacement value, including: Make the six-dimensional precision calibration displacement stage move back and forth along the direction of the attitude vector, and ensure that the fluorescent microsphere can be imaged on the charge-coupled image sensor, obtain the functional relationship between the height of the fluorescent microsphere at different longitudinal object planes and the XY-axis width ratio, that is, the longitudinal object plane height function; translate the six-dimensional precision calibration displacement stage by an actual displacement value on each longitudinal object plane, obtain the measured displacement value of the fluorescent microsphere on the charge-coupled image sensor, divide the measured displacement value of the fluorescent microsphere by the actual displacement value to obtain the microscopic magnification on each longitudinal object plane, and determine the microscopic magnification function according to different microscopic magnifications corresponding to different longitudinal object plane heights.

6. The method for detecting the spindle error of the rotary table of the upper shaft type laser tracker by connecting the overall measurement optical path according to claim 1, characterized in that Fix the first gear and the second gear on the first rotating shaft and the second rotating shaft of the upper turntable respectively, and fix a bracket with a gear transmission shaft on one side on the tabletop of the lower turntable, including: Fix the first gear and the second gear on the first rotating shaft and the second rotating shaft of the upper turntable respectively, and fix a bracket with a gear transmission shaft on one side on the tabletop of the lower turntable. When the lower turntable rotates, it drives the upper turntable and the bracket to rotate. The bracket is fixed to the gear transmission shaft through a bearing. The two ends of the gear transmission shaft are respectively engaged with the first gear and the second gear of the upper turntable. When the first rotating shaft of the upper turntable rotates, the rotational force is transmitted to the gear transmission shaft through the first gear, causing the gear transmission shaft to rotate, and then driving the second gear to rotate, thereby causing the second rotating shaft to rotate.

7. The method for detecting the rotational axis error of the turntable of the upper rotational axis type laser tracker by connecting the overall measurement optical path according to claim 1, wherein Fix the microscope on a six-dimensional precision adjustment displacement stage, fix the substrate with fluorescent microspheres on the tabletop of a micro translation adjustment stage, and fix the micro translation adjustment stage on the upper turntable, the first rotating shaft, the second rotating shaft and the lower turntable rotating shaft in sequence, including: Fix the microscope on a six-dimensional precision adjustment displacement stage; fix the substrate with fluorescent microspheres on the tabletop of a micro translation adjustment stage, and finely adjust the spatial position of the fluorescent microspheres through the micro translation adjustment stage; fix the micro translation adjustment stage on the first rotating shaft, the second rotating shaft of the upper turntable and the lower turntable rotating shaft in sequence. After each fixation of the micro translation adjustment stage, start the motor of the upper turntable or the lower turntable to make the corresponding rotating shaft rotate one circle, and ensure that the fluorescent microspheres are imaged by the microscope during one circle of rotation of the rotating shaft.

8. The method for detecting the rotational shaft error of the turntable of the upper rotational shaft type laser tracker by connecting the overall measurement optical path according to claim 1, wherein Fix the micro translation adjustment stage with fluorescent microspheres and the substrate on the lower turntable rotating shaft, start the motor of the lower turntable, make the lower turntable rotating shaft rotate a minimum step angle and then stop, record the image of the fluorescent microspheres by the microscope, determine the centroid coordinates and the XY-axis width ratio in the imaging plane coordinates of the charge-coupled image sensor through a two-dimensional Gaussian function, determine the microscopic magnification corresponding to the longitudinal object plane height where the fluorescent microspheres are located according to the XY-axis width ratio, and determine the spatial coordinate values of the fluorescent microspheres mapped to the imaging plane coordinates of the charge-coupled image sensor according to the centroid coordinates and the microscopic magnification, including: Fix the micro translation adjustment stage with the fluorescent microsphere substrate on the rotating shaft of the lower turntable. Start the motor of the lower turntable to rotate the rotating shaft of the lower turntable by a minimum step angle and then stop. Record the imaging of the fluorescent microsphere by the microscope. Obtain the centroid coordinates and the XY-axis width ratio in the imaging plane coordinates of the charge-coupled image sensor by fitting the imaging light intensity with a two-dimensional Gaussian function. Determine the value of the microscopic magnification function corresponding to the longitudinal object plane height where the fluorescent microsphere is located at this time through the XY-axis width ratio, that is, the microscopic magnification at this time. Divide the centroid coordinates by the microscopic magnification to obtain the spatial coordinate value of the fluorescent microsphere mapped to the imaging plane coordinates of the charge-coupled image sensor. By analogy, after the lower turntable rotates one circle, a series of corresponding spatial coordinate values of the fluorescent microsphere are obtained. Fit the series of spatial coordinate values of the fluorescent microsphere with a plane ellipse function to obtain the plane mapping spatial trajectory. 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 with the smallest step size. Obtain a length value of the major and minor axes of the fitted ellipse for each posture. When the major and minor axes of the fitted ellipse corresponding to a certain posture are the minimum values among all the traversed pitch and yaw postures, that is, the length of the spatial plane trajectory mapped when the rotation axis is perpendicular to the imaging plane is the shortest. At this time, the rotation axis of the lower turntable is parallel to the imaging optical axis of the fluorescence microscope.

9. The method for detecting the rotational shaft error of the rotary table of the upper shaft type laser tracker by connecting the overall measurement optical path according to claim 1, characterized in that Construct a first reference coordinate system according to the spatial coordinate values. Determine the spatial straight line equation of the rotation axis of the lower turntable in the first reference coordinate system to obtain the radial runout value within a complete rotation period of the rotating shaft of the lower turntable, including: In the case where the rotation axis of the lower turntable is parallel to the imaging optical axis of the microscope, on the premise of obtaining the imaging light intensity of the fluorescent microspheres corresponding to all the step rotations of the lower turntable and the coordinates of the imaging plane of the charge-coupled image sensor, the centroid coordinates and the XY-axis width ratio in the imaging plane coordinates of the charge-coupled image sensor are obtained by two-dimensional Gaussian fitting of the imaging light intensity. The corresponding longitudinal object plane height value and the microscopic magnification are obtained through the XY-axis width ratio. The centroid coordinates are divided by the microscopic magnification to obtain the spatial coordinate values of the fluorescent microspheres mapped to the imaging plane coordinates of the charge-coupled image sensor. Let the center coordinates obtained by fitting the spatial coordinate values with a plane ellipse function be ( x 拟 , y 拟 ). The origin of the coordinate system of the imaging plane of the charge-coupled image sensor is translated to the intersection coordinates of the imaging optical axis and the imaging plane of the charge-coupled image sensor ( x o , y o ), and then translated along the imaging optical axis direction to the focal longitudinal object plane. The corresponding coordinate system is denoted as the first reference coordinate system X 基 Y 基 Z 基 . The first reference coordinate system is the measurement coordinate system of the microscope at this time; the spatial coordinate values of the fluorescent microspheres mapped to the imaging plane coordinates of the charge-coupled image sensor are subtracted from the intersection coordinates ( x o , y o ) to obtain the XY-axis plane coordinate values of the fluorescent microspheres in the first reference coordinate system X 基 Y 基 Z 基 . The obtained longitudinal object plane height value is the Z-axis coordinate value in the first reference coordinate system X 基 Y 基 Z 基 ; the spatial straight line equation passing through the point ( 基 Y 基 Z 基 in the first reference coordinate system X x 拟 - x o , y 拟 - y o , 0) and with (0, 0, 1) as the direction is obtained, which is the rotation axis of the lower turntable; in the first reference coordinate system X 基 Y 基 Z 基 Among them, the axial runout values of all the lower turntable rotation shafts within a complete rotation period are the differences between the Z-axis values of the fluorescent microspheres corresponding to each rotation step angle of the lower turntable rotation shaft and the Z-axis value of the fluorescent microspheres at the moment of non-rotation. The radial runout values of the lower turntable rotation shaft within a complete rotation period are the differences between the distances from the XY-axis plane coordinates of the fluorescent microspheres corresponding to each rotation step angle of the lower turntable rotation shaft to the origin and the distances from the coordinate points on the fitting plane ellipse function corresponding to the rotation step angle to the origin.

10. The method for detecting the spindle error of the rotary table of the upper spindle type laser tracker by connecting the overall measurement optical path according to claim 1, characterized in that, Set the rotating shaft of the lower turntable to be stationary. Record the spatial coordinate values of the fluorescent microsphere in the first reference coordinate system at this time. Construct the motion coordinate system of the six-dimensional precision adjustment displacement stage. Determine the first vector value of the unit vector on the X-axis of the motion coordinate system in the first reference coordinate system. Determine the first coordinate value of the origin of the motion coordinate system in the first reference coordinate system. Rotate the six-dimensional precision adjustment displacement stage by a first angle around the X-axis of the motion coordinate system. Rotate the unit vector in the first reference coordinate system by the first angle around the first vector value to obtain the second vector value, including: Ensure that the rotating shaft of the lower turntable is stationary, and record the spatial coordinate values of the fluorescent microspheres in the first reference coordinate system X 基 Y 基 Z 基 at this time; construct the moving coordinate system X of the six-dimensional precision adjustment displacement stage 调 Y 调 Z 调 . Assume that the unit vector on the X-axis of the moving coordinate system X 调 Y 调 Z 调 of the six-dimensional precision adjustment displacement stage in the first reference coordinate system X 基 Y 基 Z 基 has the first vector value of ( u X , u Y ,u Z ), and the origin of the moving coordinate system X 调 Y 调 Z 调 has the first coordinate value of ( 基 Y 基 Z 基 in the first reference coordinate system X o X , o Y ,o Z ). Rotate the six-dimensional precision adjustment displacement stage by a first angle around the X-axis of the moving coordinate system X 调 Y 调 Z 调 , that is, rotate by the first angle around the first vector value ( 基 Y 基 Z 基 ) in the moving coordinate system X u X , u Y ,u Z ). Rotate the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) in the first reference coordinate system X 基 Y 基 Z 基 by the first angle around the first vector value ( u X , u Y ,u Z ); rotate the first reference coordinate system X 基 Y 基 Z 基 The unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) in o X , o Y ,o Z are respectively subtracted from the first coordinate values ( u X , u Y ,u Z ), and then respectively right-multiplied by the first rotation transformation matrix to obtain the second vector values corresponding to the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) after rotating the first vector values ( 基 Y 基 Z 基 by the first angle in the first reference coordinate system X The expression of the first rotation transformation matrix is: Among them, u X , u Y , u Z are the values of the X-axis, Y-axis, and Z-axis of the first vector value respectively, θ is the first angle; Subtract the unit vectors (1, 0, 0), (0, 1, 0), and (0, 0, 1) in the first reference coordinate system X 基 Y 基 Z 基 from the first coordinate values ( o X , o Y ,o Z ), respectively, to obtain (1 - o X , - o Y , - o Z ), (- o X , 1 - o Y , - o Z ), and (- o X , - o Y , 1 - o Z ). Then, right-multiply these results by the first rotation transformation matrix to obtain second vector values. Next, add these second vector values to the first coordinate values ( o X , o Y ,o Z ), respectively, to obtain ( i x , i y , i z ), ( j x , j y , j z ), and ( k x , k y , k z ). Subtract the origin coordinates (0, 0, 0) from the first coordinate values ( o X , o Y ,o Z ), right-multiply the result by the first rotation transformation matrix, and then add it to the first coordinate values ( o X , o Y ,o Z ) added together to obtain ( t x , t y , t z ), then in the first reference coordinate system X 基 Y 基 Z 基 the unit vectors (1, 0, 0), (0, 1, 0) and (0, 0, 1) rotate around the first vector value ( u X , u Y ,u Z ) by the first angle, and the second vector values in the first reference coordinate system X 基 Y 基 Z 基 are respectively ( i x - t x , i y - t y , i z - t z ), ( j x - t x , j y - t y , j z - t z ) and ( k x - t x , k y - t y , k z - t z ).

11. The method for detecting the rotational axis error of the turntable of the upper rotational axis type laser tracker by connecting the overall measurement optical path according to claim 1, characterized in that Rotate the first reference coordinate system by the first angle around the X-axis of the motion coordinate system to obtain the measurement coordinate system of the microscope. Determine the spatial coordinate values of the fluorescent microsphere in the measurement coordinate system to obtain the spatial coordinate relationship of the fluorescent microsphere before and after the six-dimensional precision adjustment displacement stage rotates by the first angle, including: The six-dimensional precision adjustment displacement stage rotates around the X-axis of the moving coordinate system X 调 Y 调 Z 调 by a first angle around the X-axis, driving the fluorescence microscope to rotate around the X-axis of the moving coordinate system X 调 Y 调 Z 调 by the first angle. At this time, the first reference coordinate system X 基 Y 基 Z 基 also rotates around the X-axis of the moving coordinate system X 调 Y 调 Z 调 by a first angle to obtain the measurement coordinate system X of the microscope θ Y θ Z θ ; similar to the case where the first reference coordinate system X 基 Y 基 Z 基 in step S8 is used as the measurement coordinate system of the microscope, the spatial coordinate values of the fluorescence microspheres in the measurement coordinate system X of the microscope θ Y θ Z θ are obtained ( x θ , y θ , z θ ), and the spatial coordinate relationship of the fluorescence microspheres before and after the rotation of the six-dimensional precision adjustment displacement stage is obtained. The expression is as follows: in,( x θ , y θ , z θ ) is the measurement coordinate system X of the fluorescent microsphere in the microscope θ Y θ Z θ The spatial coordinate value in ; ( i x - t x , i y - t y , i z - t z )、( j x - t x , j y - t y , j z - t z )and( k x - t x , k y - t y , k z - t z ) are the first reference coordinate system X 基 Y 基 Z 基 The unit vectors (1,0,0), (0,1,0), and (0,0,1) are centered around the first vector value ( u X , u Y ,u Z ) After rotating the first angle in the first reference coordinate system X 基 Y 基 Z 基 The second vector value in ; The X coordinate of the fluorescent microsphere in the first reference coordinate system when the lower turntable axis is stationary 基 Y 基 Z 基 The spatial coordinate value in .

12. The method for detecting the spindle error of the rotary table of an upper spindle type laser tracker by connecting the overall measurement optical path according to claim 11, characterized in that Rotate the six-dimensional precision adjustment displacement stage back to the starting posture. Determine the third vector value of the unit vector on the Y-axis of the motion coordinate system of the six-dimensional precision adjustment displacement stage in the first reference coordinate system. Rotate the six-dimensional precision adjustment displacement stage by a second angle around the Y-axis of the motion coordinate system to obtain the spatial coordinate relationship of the fluorescent microsphere before and after the six-dimensional precision adjustment displacement stage rotates by the second angle. Obtain the first vector value, the first coordinate value, and the third vector value through the least squares method, including: Rotate the six - dimensional precision adjustment displacement stage back to the starting attitude in step S9. Assume the moving coordinate system X of the six - dimensional precision adjustment displacement stage 调 Y 调 Z 调 The unit vector on the Y - axis of which has a third vector value in the first reference coordinate system X 基 Y 基 Z 基 is ( v X , v Y ,v Z ). Rotate the six - dimensional precision adjustment displacement stage around the Y - axis of the moving coordinate system X 调 Y 调 Z 调 by a second angle. Similarly, obtain a spatial coordinate relationship of the fluorescent microspheres before and after the rotation of the six - dimensional precision adjustment displacement stage similar to expression (Ⅱ); obtain six relationships about nine unknowns, namely the first vector value ( u X , u Y ,u Z ), the first coordinate value ( o X , o Y ,o Z ), and the third vector value ( v X , v Y ,v Z ). Repeat steps S9 to S11, rotate more different first angles and second angles to obtain more relationships than the number of nine unknowns, thus constructing an over - determined system of equations, and calculate the first vector value ( u X , u Y ,u Z ), the first coordinate value ( o X , o Y ,o Z ), and the third vector value ( v X , v Y , v Z ) by the least - squares method.

13. The method for detecting the rotational axis error of the rotary table of the upper shaft type laser tracker by connecting the overall measurement optical path according to claim 1, characterized in that, Fix the micro translation adjustment stage with fluorescent microspheres and a substrate on the first rotating shaft of the upper turntable. Start the motor of the upper turntable to control the rotation of the first rotating shaft, construct the second reference coordinate system, determine the spatial straight-line equation of the rotation axis on the motor side of the upper turntable in the second reference coordinate system, and obtain the axial and radial runout values within a complete rotation period, including: Fix the micro translation adjustment stage with the fluorescent microsphere substrate on the first rotating shaft of the upper turntable, start the upper turntable motor to control the rotation of the first rotating shaft, and the remaining operations are the same as in step S7 and step S8. At this time, the measurement coordinate system of the microscope is X’ 基 Y’ 基 Z’ 基 , that is, the second reference coordinate system is X’ 基 Y’ 基 Z’ 基 ; Since the imaging fluorescence of the fluorescent microspheres is transmitted to the side beam incident surface of the standard 45-degree beam splitting cube for imaging, due to the mirroring effect of the beam splitting surface of the standard 45-degree beam splitting cube, the obtained is the spatial coordinate values of the symmetric mirror image of the fluorescent microspheres in the second reference coordinate system X’ 基 Y’ 基 Z’ 基 . The spatial coordinate values are uniformly expressed as ( x’ , y’,z’ ); According to the distance D between the focal longitudinal object plane of the microscope and the center point of the beam splitting surface in step S1, the spatial coordinate values of the actual fluorescent microspheres in the second reference coordinate system X’ 基 Y’ 基 Z’ 基 are ( x’ , y’ -D ,z’ +D). Similar to step S8, in the second reference coordinate system X’ 基 Y’ 基 Z’ 基 , obtain the spatial straight line equation of the rotation axis on the upper turntable motor side and the axial and radial runout values within a complete rotation period.

14. The method for detecting the spindle error of the rotary table of an upper-rotating shaft type laser tracker by connecting the overall measurement optical path according to claim 1, characterized in that, Determine the yaw angle and pitch angle of the second reference coordinate system relative to the first reference coordinate system according to the six-dimensional precision adjustment displacement stage. Rotate the unit vector in the first reference coordinate system by the yaw angle and pitch angle to obtain the spatial coordinate values of the fluorescent microspheres in the first reference coordinate system in the second reference coordinate system. Convert the spatial straight-line equation of the rotation axis of the upper turntable into the spatial straight-line equation in the first coordinate system, including: Since the second reference coordinate system X’ 基 Y’ 基 Z’ 基 is determined by the principle that the length of the spatial plane trajectory mapped when the rotation axis is perpendicular to the imaging plane is the shortest, the second reference coordinate system X’ 基 Y’ 基 Z’ 基 has an attitude difference from the first reference coordinate system X 基 Y 基 Z 基 This attitude difference is due to the attitude of the six-dimensional precision adjustment displacement stage corresponding to the first reference coordinate system X 基 Y 基 Z 基 and the attitude of the six-dimensional precision adjustment displacement stage corresponding to the second reference coordinate system X’ 基 Y’ 基 Z’ 基 having a yaw angle and a pitch angle. The yaw angle and the pitch angle are determined by the six-dimensional precision adjustment displacement stage. Denote the yaw 基 Y 基 Z 基 and pitch θ’ angles of the first reference coordinate system X δ’ After that, it becomes the second reference coordinate system X’ 基 Y’ 基 Z’ 基 , and the second rotation transformation matrix that needs to be right-multiplied is: Among them, θ’ is the yaw angle, δ’ is the pitch angle, ( u X , u Y ,u Z ) is the first vector value of the unit vector on the X-axis of the moving coordinate system X 调 Y 调 Z 调 of the six-dimensional precision adjustment displacement stage in the first reference coordinate system X 基 Y 基 Z 基 ; ( v X , v Y ,v Z ) is the third vector value of the unit vector on the Y-axis of the moving coordinate system X 调 Y 调 Z 调 of the six-dimensional precision adjustment displacement stage in the first reference coordinate system X 基 Y 基 Z 基 ; Through the second rotation transformation matrix and the moving coordinate system X 调 Y 调 Z 调 The origin of which in the first reference coordinate system X 基 Y 基 Z 基 The first coordinate values in ( o X , o Y ,o Z ), similar to the operation in step S9, the unit vectors (1, 0, 0), (0, 1, 0), (0, 0, 1) and the origin (0, 0, 0) in the first reference coordinate system X 基 Y 基 Z 基 Are respectively transformed into ( i' x , i' y , i' z ), ( j' x , j' y , j' z ), ( k' x , k' y , k' z ), and ( t' x , t' y , t' z ), so as to obtain the unit vectors (1, 0, 0), (0, 1, 0) and (0, 0, 1) in the first reference coordinate system X 基 Y 基 Z 基 After yaw θ’ And pitch δ’ The angles, in the first reference coordinate system X 基 Y 基 Z 基 Are respectively changed to ( i' x - t' x , i' y - t' y , i' z - t' z ), ( j' x - t' x , j' y - t' y , j' z - t' z ), and ( k' x - t' x , k' y - t' y , k' z - t' z ), the spatial coordinates of the fluorescent microspheres in the second reference coordinate system X' 基 Y' 基 Z' 基 are obtained as ( x’ , y’ -D ,z’ +D), which are corresponding to the spatial coordinate values ( 基 Y 基 Z 基 in the first reference coordinate system X x’ 基 , y’ 基 , z’ 基 ), and the expression is: ； The second reference coordinate system X’ 基 Y’ 基 Z’ 基 For any two coordinate values on the space straight line equation of the rotation axis on the motor side of the upper turntable in, after being converted by the expression (IV), the coordinate values in the first reference coordinate system X 基 Y 基 Z 基 are obtained, so as to determine the coordinate values in the first reference coordinate system X 基 Y 基 Z 基 and the space straight line equation in, that is, to realize the determination of the space straight line equations of the rotation axis of the lower turntable and the rotation axis on the motor side of the upper turntable in the same coordinate system.

15. The method for detecting the rotational axis error of the rotary table of the upper shaft type laser tracker by connecting the overall measurement optical path according to claim 1, characterized in that, Fix the micro translation adjustment stage with fluorescent microspheres and a substrate on the second rotating shaft of the upper turntable, and start the motor of the lower turntable. Rotate 180 degrees to symmetrically interchange the positions of the encoder side and the motor side of the upper turntable, obtain the axial and radial runout values within a complete rotation period, determine the spatial straight-line equations of the rotation axis of the lower turntable and the rotation axis of the encoder side of the upper turntable in the first reference coordinate system, and realize the determination of the spatial straight-line equations of the rotation axis of the lower turntable, the rotation axis of the motor side of the upper turntable, and the rotation axis of the encoder side of the upper turntable and the error detection within a complete rotation period in the same reference coordinate system, including: Fix the micro translation adjustment stage with the fluorescent microsphere substrate on the second rotating shaft of the upper turntable, and start the lower turntable motor. Rotate 180 degrees to symmetrically interchange the positions of the encoder side and the motor side of the upper turntable. Similar to steps S12 and S13, obtain the axial and radial runout values within a complete rotation cycle; in the first reference coordinate system X 基 Y 基 Z 基 Determine the space straight line equations of the rotation axis of the lower turntable and the rotation axis of the encoder side of the upper turntable to realize the error detection of the rotation axis of the lower turntable, the rotation axis of the motor side of the upper turntable, and the rotation axis of the encoder side within a complete rotation cycle, and determine the rotation axis of the lower turntable, the rotation axis of the motor side of the upper turntable, and the rotation axis of the encoder side in the same first reference coordinate system X 基 Y 基 Z 基 The space straight line equations below.

16. An error detection device for the rotation axis of a rotary table of a spindle-mounted laser tracker in an overall measurement optical path connection, characterized in that, A method for detecting the rotation shaft error of the upper rotating shaft type laser tracker turntable for implementing the overall measurement optical path as described in any one of claims 1 to 15, including: a microscope, fluorescent microspheres, a substrate, and a six-dimensional precision calibration displacement stage, wherein the microscope is located above the fluorescent microspheres, the fluorescent microspheres are fixed on the substrate, and the substrate is fixed on the six-dimensional precision calibration displacement stage.

Images