Orthogonal axis system calibration method and coordinate measuring device

Abstract

The application provides a method for calibrating a quadrature axis system and a coordinate measuring device. The method comprises: obtaining a third virtual section by cutting a second rotating shaft with a second section surface which is spaced apart from the axis of the first rotating shaft by a second preset distance; rotating the first rotating shaft to rotate the second rotating shaft by a first preset angle, and obtaining a fourth virtual section by cutting the second rotating shaft with the second section surface; calculating an out-of-plane error for reflecting the distance between the axis of the first rotating shaft and the axis of the second rotating shaft based on the geometric center of the third virtual section and the geometric center of the fourth virtual section; and adjusting the relative position of the axis of the first rotating shaft and the axis of the second rotating shaft based on the out-of-plane error to reduce the out-of-plane error if the out-of-plane error is not less than a second preset value. Thus, the out-of-plane error of the quadrature axis system can be reduced.

Description

[0001] This application is a divisional application of the patent application filed on September 15, 2021, with application number 2021110818558, entitled "Calibration Method of Orthogonal Axis System for Coordinate Measuring Instrument". Technical Field

[0002] This disclosure generally relates to an intelligent manufacturing equipment industry, and more specifically to a calibration method and coordinate measuring device for an orthogonal axis system. Background Technology

[0003] In precision industry and measurement fields, when assembling large machines, precision instruments (such as laser measuring instruments) are often used to test the assembled target to improve assembly accuracy. After assembly, the machine also needs calibration. Furthermore, during assembly, in addition to measuring the three-dimensional coordinates of the target object or a specific point on it, the motion of the target object or point also needs to be measured—that is, their attitude needs to be detected. Therefore, an instrument capable of measuring six degrees of freedom in addition to three-dimensional coordinates is needed. This has led to the development of a measurement method that uses coordinate measuring instruments to measure the attitude of target objects or points. The measurement accuracy of coordinate measuring instruments mainly depends on the accuracy of angle and distance measurements. To improve the measurement accuracy of coordinate measuring instruments, it is necessary to ensure the non-planar error and perpendicularity error of the orthogonal axis system (at least including the horizontal and pitch axes). Therefore, the measurement and calibration methods for the non-planar error and perpendicularity error of the orthogonal axis system of coordinate measuring instruments are very important.

[0004] Patent document (CN106705821A) discloses a method and apparatus for measuring the orthogonality of a rotary axis system. This apparatus mounts two standard spheres at opposite ends of a pitch rotation axis. By adjusting the centers of the standard spheres to be coaxial with the axis of the pitch rotation axis, and then measuring the lowest or highest positions of the two standard spheres in the same direction, the orthogonality of the axis system is determined. However, while this method and apparatus can obtain orthogonal measurement results for the two axis systems, errors are introduced during the process of adjusting the centers of the two standard spheres to be coaxial with the axis of the pitch axis. Furthermore, measuring the lowest or highest positions of the two standard spheres also introduces errors. These two types of errors significantly affect the accuracy of the axis orthogonality measurement results. Additionally, this method cannot obtain information about non-planar errors. Summary of the Invention

[0005] The present invention is proposed in view of the above-mentioned state of the prior art, and its purpose is to provide a calibration method for the orthogonal axis system of a coordinate measuring instrument that can reduce non-planar errors and perpendicular errors.

[0006] To address this, the present invention provides a calibration method for an orthogonal axis system of a coordinate measuring instrument. The coordinate measuring instrument includes a first rotating device having a first rotating axis and a second rotating device disposed on the first rotating device and having a second rotating axis. The second rotating device is capable of rotating around the first rotating device. The orthogonal axis system is composed of the first rotating axis and the second rotating axis. The method is characterized by comprising: measuring the perpendicular error between the axes of the first and second rotating axes, wherein the perpendicular error reflects the angle between the axes of the first and second rotating axes; when measuring the perpendicular error, using a first cross-section spaced a first preset distance from the axis of the first rotating axis to intercept the second rotating axis to obtain a first virtual cross-section; rotating the first rotating axis to rotate the second rotating axis by a first preset angle; and using the first cross-section... A second virtual cross section is obtained by cutting the second rotation axis. The vertical error is calculated based on the position of the geometric center of the first and second virtual cross sections. If the vertical error is not less than a first preset value, the relative position of the axis of the first rotation axis and the second rotation axis is adjusted based on the vertical error to reduce the vertical error. The non-planar error of the axis of the first rotation axis and the axis of the second rotation axis is measured. The non-planar error reflects the distance between the axis of the first rotation axis and the axis of the second rotation axis. If the non-planar error is less than a second preset value, the relative position of the axis of the first rotation axis and the second rotation axis is adjusted based on the vertical error to reduce the non-planar error. The vertical error is repeatedly adjusted to make the vertical error less than the first preset value, and the non-planar error is repeatedly adjusted to make the non-planar error less than the second preset value.

[0007] In this configuration, the vertical error can be measured and adjusted during the assembly of the first and second rotating axes, thereby reducing the vertical error and improving the measurement accuracy of the coordinate measuring instrument. Simultaneously, since the second rotating axis is cut using the same cross-section when measuring the first and second virtual cross-sections, the first and second virtual cross-sections are obtained in the same plane. This reduces the horizontal movement of the probe (e.g., the probe of a coordinate measuring machine) when measuring the geometric centers of the first and second virtual cross-sections, thus reducing the error introduced during measurement. Furthermore, the skewness error can be further adjusted after adjusting the vertical error, further improving the measurement accuracy of the coordinate measuring instrument. Additionally, since the movement of the second rotating axis is small when adjusting the skewness error, the impact of large movements of the relative position of the second and first rotating axes on the vertical error is reduced. Repeated adjustments to the skewness and vertical errors further reduce the impact of moving the relative position of the second and first rotating axes on both the vertical and skewness errors.

[0008] Additionally, in the calibration method of this invention, optionally, when measuring the non-planar error, the second rotating axis is intercepted using a second cross-section spaced a second preset distance from the axis of the first rotating axis to obtain a third virtual cross-section. The first rotating axis is rotated to rotate the second rotating axis by a first preset angle. The second rotating axis is then intercepted using the second cross-section to obtain a fourth virtual cross-section. The non-planar error is calculated based on the geometric centers of the third and fourth virtual cross-sections. When the third virtual cross-section is obtained, the second rotating axis and the second cross-section have a second preset angle. In this case, the distance between the geometric centers of the third and fourth virtual cross-sections can be greater than or equal to twice the distance between the axes of the first and second rotating axes. This allows a larger value to reflect the distance between the axes of the first and second rotating axes, improving measurement accuracy.

[0009] Alternatively, in the calibration method of the present invention, the second rotating device may include a first support portion and a second support portion, and the second rotating shaft may be rotatably disposed between the first support portion and the second support portion. In this case, the second rotating shaft can be rotated in a second direction.

[0010] Additionally, in the calibration method of this invention, optionally, the second rotating device further includes a first bearing disposed on the first support portion and a second bearing disposed on the second support portion, and the second rotating shaft is mounted on the second rotating device via the first bearing and the second bearing. In this case, the stability of the second rotating shaft during rotation can be improved, and since the straight line containing the axis of the first bearing and the axis of the second bearing is the axis of the second rotating shaft, the attitude of the second rotating shaft can be controlled by adjusting the positions of the first bearing and the second bearing.

[0011] Additionally, in the calibration method of this invention, optionally, if the vertical error is not less than the first preset value, the relative position of the first bearing and the first support portion or the relative position of the second bearing and the second support portion is adjusted to adjust the angle between the axis of the first rotating shaft and the axis of the second rotating shaft. In this case, the vertical error can be effectively reduced.

[0012] Additionally, in the calibration method of this invention, optionally, if the misalignment error is not less than the second preset value, the relative positions of the first bearing and the first support portion and the second bearing and the second support portion are adjusted to adjust the distance between the axis of the first rotating shaft and the axis of the second rotating shaft. In this case, the misalignment error can be reduced.

[0013] Alternatively, in the adjustment method of the present invention, the first bearing may include a first positioning screw configured to position the first bearing on a first support portion, and the second bearing may include a second positioning screw configured to position the second bearing on a second support portion. In this case, the first bearing can be positioned by tightening the first positioning screw, and the position of the first bearing can be adjusted by loosening the first positioning screw. Similarly, the second bearing can be positioned by tightening the second positioning screw, and the position of the second bearing can be adjusted by loosening the second positioning screw.

[0014] Furthermore, in the adjustment method of this invention, optionally, when adjusting the relative position of the first bearing and the first support, the first positioning screw is loosened and the first bearing is adjusted based on the vertical error or the non-planar error, and after adjusting the relative position of the first bearing and the first support, the first positioning screw is tightened; when adjusting the relative position of the second bearing and the second support, the second positioning screw is loosened and the second bearing is adjusted based on the vertical error or the non-planar error, and after adjusting the relative position of the second bearing and the second support, the second positioning screw is tightened. In this case, the first bearing can be positioned by tightening the first positioning screw, and the position of the first bearing can be adjusted by loosening the first positioning screw. Simultaneously, the second bearing can be positioned by tightening the second positioning screw, and the position of the second bearing can be adjusted by loosening the second positioning screw.

[0015] Furthermore, in the calibration method of this invention, optionally, when the vertical error is less than the first preset value and the non-planar error is less than the second preset value, the first bearing and the second bearing are fixed. In this case, the calibrated vertical error and non-planar error can be fixed, and the relative positional relationship between the first rotation axis and the second rotation axis can be fixed.

[0016] Additionally, in the calibration method of this invention, optionally, if the non-planar error is not less than the second preset value, the relative position of the second rotating device and the first rotating device is adjusted to adjust the distance between the axis of the first rotating shaft and the axis of the second rotating shaft. In this case, the influence of adjusting the first bearing and the second bearing on the perpendicularity error can be avoided.

[0017] According to the present invention, a calibration method for the orthogonal axis system of a coordinate measuring instrument is provided, which can reduce non-planar errors and perpendicular errors. Attached Figure Description

[0018] Embodiments of the invention will now be explained in further detail by way of example with reference to the accompanying drawings, wherein:

[0019] Figure 1 This is a schematic diagram showing the coordinate measuring instrument involved in this disclosure.

[0020] Figure 2 This is a schematic diagram showing the second rotating device of the coordinate measuring instrument involved in this disclosure.

[0021] Figure 3 This is a schematic diagram showing the connection between the second rotation axis and the optical body of the coordinate measuring instrument involved in this disclosure.

[0022] Figure 4 This is a perspective view of the orthogonal axis system involved in this disclosure without the second rotation axis installed.

[0023] Figure 5 This is a perspective view of the orthogonal axis system with the second rotating axis installed, as described in this disclosure.

[0024] Figure 6 This is a flowchart illustrating the calibration method involved in this disclosure.

[0025] Figure 7 This is a schematic diagram showing the spatial coordinates of the geometric center of the first virtual cross-section as described in this disclosure.

[0026] Figure 8 This is a schematic diagram showing the spatial coordinates of the geometric center of the second virtual cross section as described in this disclosure.

[0027] Figure 9 This is a schematic diagram showing the spatial coordinates of the geometric center of the third virtual section involved in this disclosure.

[0028] Figure 10 This is a schematic diagram showing the spatial coordinates of the geometric center of the fourth virtual section involved in this disclosure. Detailed Implementation

[0029] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same parts, and repeated descriptions are omitted. Furthermore, the drawings are merely schematic diagrams, and the proportions of the parts or the shapes of the parts may differ from the actual figures.

[0030] It should be noted that the terms "comprising" and "having" and any variations thereof in this invention, such as a process, method, system, product, or device that includes or has a series of steps or units, are not necessarily limited to those steps or units that are explicitly listed, but may include or have other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0031] Furthermore, the subheadings and similar terms used in the following description of this invention are not intended to limit the content or scope of this invention; they are merely for reading guidance. Such subheadings should not be construed as dividing the content of the article, nor should the content under a subheading be limited to the scope of that subheading.

[0032] This embodiment relates to a method for calibrating the orthogonal axis system of a coordinate measuring instrument. The coordinate measuring instrument is used to track an auxiliary measuring device and measure its spatial coordinates and attitude. "Coordinate measuring instrument" can also be called "coordinate measuring device," and "auxiliary measuring device" can also be called "attitude target," "attitude target," "target," or "target ball." The "calibration method for the orthogonal axis system of the coordinate measuring instrument" can also be called "calibration method." Using the coordinate measuring instrument described in this embodiment, it is possible to track a target ball and then measure its spatial coordinates and attitude.

[0033] In the calibration method of the orthogonal axis system of a coordinate measuring instrument according to this embodiment, the coordinate measuring instrument includes a first rotating device having a first rotating axis and a second rotating device disposed on the first rotating device and having a second rotating axis. The second rotating device is capable of rotating around the first rotating device, and the orthogonal axis system is composed of the first rotating axis and the second rotating axis.

[0034] In some examples, the calibration method may include: measuring the perpendicular error between the axes of a first rotation axis and a second rotation axis, the perpendicular error reflecting the angle between the axes of the first and second rotation axes; when measuring the perpendicular error, using a first cross-section spaced a first preset distance from the axis of the first rotation axis to intercept the second rotation axis to obtain a first virtual cross-section; rotating the first rotation axis to rotate the second rotation axis by a first preset angle; using the first cross-section to intercept the second rotation axis to obtain a second virtual cross-section; calculating the perpendicular error based on the position of the geometric center of the first and second virtual cross-sections; if the perpendicular error is not less than a first preset value, adjusting the relative position of the axes of the first and second rotation axes based on the perpendicular error to reduce the perpendicular error. In this case, the perpendicular error can be measured and adjusted during the assembly of the first and second rotation axes, thereby reducing the perpendicular error and improving the measurement accuracy of the coordinate measuring instrument. Meanwhile, since the same cross section is used to cut the second rotation axis when measuring the first virtual cross section and the second virtual cross section, the first virtual cross section and the second virtual cross section in the same plane can be obtained. This reduces the horizontal movement of the probe (e.g., the probe of a coordinate measuring machine) when measuring the geometric center of the first virtual cross section and the second virtual cross section, thereby reducing the error introduced during measurement.

[0035] In some examples, the skewness error between the axes of the first and second rotation axes is measured. This skewness error reflects the distance between the axes of the first and second rotation axes. If the skewness error is less than a second preset value, the relative positions of the axes of the first and second rotation axes are adjusted based on the perpendicularity error to reduce the skewness error. In this case, the skewness error can be further adjusted after adjusting the perpendicularity error, thereby improving the measurement accuracy of the coordinate measuring instrument. Simultaneously, because the movement of the second rotation axis is small when adjusting the skewness error, the impact of large movements of the relative positions of the second and first rotation axes on the perpendicularity error is reduced.

[0036] In some examples, the vertical error can be repeatedly adjusted to make it less than a first preset value, and the non-planar error can be repeatedly adjusted to make it less than a second preset value. In this case, the influence of moving the relative position of the second rotation axis and the first rotation axis on the vertical error and the non-planar error can be further reduced.

[0037] The calibration method described in this embodiment will now be explained in detail with reference to the accompanying drawings.

[0038] Figure 1 This is a schematic diagram showing the coordinate measuring instrument involved in this disclosure. Figure 2 This is a schematic diagram showing the second rotating device of the coordinate measuring instrument involved in this disclosure. Figure 3This is a schematic diagram showing the connection between the second rotation axis and the optical body of the coordinate measuring instrument involved in this disclosure. Figure 4 This is a perspective view of the orthogonal axis system involved in this disclosure without the second rotation axis installed. Figure 5 This is a perspective view of the orthogonal axis system with the second rotating axis installed, as described in this disclosure.

[0039] In some examples, such as Figure 1 As shown, the coordinate measuring instrument 1 may include a first rotating device 10, a second rotating device 20, and an optical body 30.

[0040] In some examples, the first rotating device 10 may be provided with a first rotating axis 11 (not shown). In some examples, the first rotating axis 11 may be referred to as an azimuth axis or a horizontal rotating axis. In some examples, the first rotating axis 11 can rotate along a first direction, preferably a horizontal direction.

[0041] In some examples, such as Figure 1 As shown, the second rotating device 20 is disposed on the first rotating device 10. In some examples, the second rotating device 20 may be disposed on the first rotating device 10, in which case the second rotating device 20 can rotate along the first direction under the drive of the first rotating shaft 11.

[0042] In some examples, such as Figure 2 and Figure 4 As shown, the second rotating device 20 may have a second rotating axis 23. In some examples, the second rotating axis 23 may be referred to as a pitch axis or a pitch rotation axis. In some examples, the second rotating axis 23 may rotate along a second direction. In some examples, the rotation direction of the first rotating axis 11 may be orthogonal to the rotation direction of the second rotating axis 23. Preferably, the second direction may be a vertical direction. In some examples, the optical body 30 may be disposed on the second rotating axis 23 of the second rotating device 20. In this case, the optical body 30 can rotate along a first direction under the drive of the first rotating axis 11, and the optical body 30 can rotate along a second direction under the drive of the second rotating axis 23.

[0043] In some examples, such as Figure 2 and Figure 5 As shown, the second rotating device 20 may further include a first support portion 21 and a second support portion 22, with a second rotating shaft 23 rotatably disposed between the first support portion 21 and the second support portion 22. In this case, the second rotating shaft 23 can be rotated in a second direction.

[0044] In some examples, the second rotating device 20 may consist only of the first support portion 21, and the second rotating shaft 23 may be rotatably disposed on the first support portion 21. In this case, the second rotating shaft 23 can be supported using only the first support portion 21, thereby simplifying the structure of the second rotating device 20.

[0045] In some examples, such as Figure 2 As shown, the second rotating device 20 may further include a first bearing 211 disposed on the first support portion 21 and a second bearing 221 disposed on the second support portion 22. The second rotating shaft 23 is mounted on the second rotating device 20 via the first bearing 211 and the second bearing 221. In this case, the stability of the second rotating shaft 23 during rotation can be improved, and since the straight line where the axis of the first bearing 211 and the axis of the second bearing 221 lie is the axis of the second rotating shaft 23, the attitude of the second rotating shaft 23 can be controlled by adjusting the positions of the first bearing 211 and the second bearing 221.

[0046] In some examples, the first bearing 211 may include a first positioning screw (not shown) configured to position the first bearing 211 against the first support portion 21, and the second bearing 221 may include a second positioning screw (not shown) configured to position the second bearing 221 against the second support portion 22. In this case, the first bearing 211 can be positioned by tightening the first positioning screw, and its position can be adjusted by loosening the first positioning screw. Similarly, the second bearing 221 can be positioned by tightening the second positioning screw, and its position can be adjusted by loosening the second positioning screw.

[0047] In some examples, the first support portion 21 may include a first clamping block (not shown), which may position the first bearing 211 on the first support portion 21. For example, the first clamping block may include a holding portion that clamps the first bearing 211 to the first support portion 21.

[0048] In some examples, the second support portion 22 may include a second clamping block (not shown), which may position the second bearing 221 on the second support portion 22. For example, the second clamping block may include a clamping portion that holds the second bearing 221 together with the second support portion 22.

[0049] In some examples, such as Figure 3As shown, openings can be located at the geometric centers of both sides of the optical main body 31, and the size of the openings can match the diameter of the second rotation shaft 23. In this case, the second rotation shaft 23 can pass through the optical main body 31, thereby driving the optical main body 31 to rotate together. At the same time, the light beam can enter the optical main body 31 through the second rotation shaft 23, thus allowing the light beam to pass well through the geometric centers of multiple optical elements, improving the utilization rate of light energy and facilitating beam adjustment.

[0050] In some examples, such as Figure 3 As shown, the second rotation axis 23 may include a protrusion 231, which may be a protrusion extending outward from the side of the second rotation axis 23, and the protrusion 231 may cooperate with the side of the optical body base 31. In this case, the optical body base 31 can be positioned.

[0051] In some examples, the radial runout of the second rotation axis 23 can be measured, and the second rotation axis 23 with a radial runout less than a second preset threshold can be assembled. In some examples, the second preset threshold can be less than 5 micrometers; for example, the preset value can be 2 micrometers, 2.5 micrometers, 2.8 micrometers, 3 micrometers, 3.4 micrometers, 4 micrometers, 4.5 micrometers, or 5 micrometers. In this case, the positional accuracy between the optical main body 31 and the second rotation axis 23 can be improved.

[0052] Figure 6 This is a flowchart illustrating a method for adjusting the orthogonality of the orthogonal axis system involved in this disclosure. In some examples, such as Figure 6 As shown, the calibration method may include: measuring vertical error (step S100), adjusting vertical error (step S200), measuring non-planar error (step S300), adjusting non-planar error (step S400), repeatedly adjusting vertical error to make vertical error less than a first preset value (step S500), and repeatedly adjusting non-planar error to make non-planar error less than a second preset value (step S600).

[0053] In step S100, the perpendicularity error between the axis of the first rotating shaft 11 and the axis of the second rotating shaft 23 can be measured.

[0054] In some examples, the vertical error can be used to reflect the angle between the axis of the first rotation axis 11 and the axis of the second rotation axis 23.

[0055] In some examples, the perpendicularity error can be the angle between the axis of the first rotation axis 11 and the axis of the second rotation axis 23. In some examples, since the axis of the first rotation axis 11 and the axis of the second rotation axis 23 are not in the same plane, the angle between the axis of the first rotation axis 11 and the axis of the second rotation axis 23 can be the angle between the axis of the first rotation axis 11 and the axis of the second rotation axis 23 after translating the axis of the first rotation axis 11 to the plane containing the axis of the second rotation axis 23.

[0056] In some examples, the perpendicular error can be the angle between the axis of the first rotation axis 11 and the axis of the second rotation axis 23 minus 90 degrees. In this case, the perpendicular error between the axes of the first rotation axis 11 and the second rotation axis 23 can be represented more intuitively. In some examples, the perpendicular error can be the vertical distance between the two ends of the second rotation axis 23, where the vertical direction can refer to the direction of the axis of the first rotation axis 11. In this case, the perpendicular error between the axes of the first rotation axis 11 and the second rotation axis 23 can be represented in the same way, thus allowing for the selection of a calculation-friendly method to represent the perpendicular error based on the measurement method.

[0057] Figure 7 This is a schematic diagram showing the spatial coordinates of the geometric center of the first virtual cross section S1 as described in this disclosure. Figure 8 This is a schematic diagram showing the spatial coordinates of the geometric center of the second virtual cross section S2 as described in this disclosure.

[0058] In some examples, such as Figure 7 and Figure 8 As shown, when measuring the vertical error, the second rotation axis 23 can be intercepted by a first section A at a first preset distance from the axis of the first rotation axis 11 to obtain a first virtual section S1. The first rotation axis 11 is rotated to rotate the second rotation axis 23 by a first preset angle. The second rotation axis 23 is intercepted by the first section A to obtain a second virtual section S2. The vertical error is calculated based on the position of the geometric center of the first virtual section S1 and the second virtual section S2.

[0059] In some examples, when measuring vertical error, the coordinate measuring instrument 1 can be placed on the bearing surface 4, and the levelness of the bearing surface 4 can be less than a first preset threshold. In some examples, the first preset threshold can be from 1 micrometer to 8 micrometers. For example, the first preset threshold can be 1 micrometer, 2 micrometers, 3 micrometers, 4 micrometers, 5 micrometers, 6 micrometers, 7 micrometers, or 8 micrometers, etc.

[0060] In some examples, the first rotation axis 11 can maintain a certain degree of perpendicularity with the bearing surface 4. This improves the accuracy of the calibration method. In some examples, the smaller the perpendicularity between the first rotation axis 11 and the bearing surface 4, the smaller the error in the measurement result.

[0061] In some examples, when the first section A cuts through the second rotation axis 23 to obtain the first virtual section S1, the first section A may be spaced from the axis of the first rotation axis 11 by a first preset distance. In some examples, the first preset distance is less than half the length of the second rotation axis 23.

[0062] In some examples, when the first section A is cut off from the second rotation axis 23 to obtain the first virtual section S1, the spatial coordinates of each measurement point (first measurement point) of the first virtual section S1 can be obtained using the measuring instrument 41.

[0063] In some examples, the first section A can be perpendicular to the bearing surface 4. In this case, when the measuring instrument 41 obtains the spatial coordinates of each measuring point (first measuring point) of the first virtual section S1, the measuring instrument 41 can move in a plane, thereby reducing the degree of freedom of the measuring instrument 41 in one direction, thus reducing the error introduced when the measuring instrument 41 moves in that direction, and thus improving the measurement accuracy.

[0064] In some examples, the coordinate measuring instrument 1 can be a coordinate measuring machine 41, which can be a detector capable of moving in three directions.

[0065] In some examples, the coordinate measuring instrument 1 can be mounted on the bearing surface 4 via a bracket 42.

[0066] In some examples, the coordinate measuring machine 41 can employ a contact measurement method. In other examples, the coordinate measuring machine 41 can also employ a non-contact measurement method. In this case, the measurement efficiency can be improved due to the high accuracy and convenience of the coordinate measuring machine 41.

[0067] In some examples, the spatial coordinates of multiple first measurement points of the first virtual cross-section S1 can be obtained using the measuring instrument 41. For instance, the probe of the measuring instrument 41 can be rotated one revolution around the first virtual cross-section S1 within the first cross-section A, and the spatial coordinates of multiple first measurement points on the edge of the first virtual cross-section S1 can be measured. Alternatively, the probe of the measuring instrument 41 can be rotated multiple revolutions around the first virtual cross-section S1 within the first cross-section A, and the spatial coordinates of multiple first measurement points on the edge of the first virtual cross-section S1 can be measured. In this case, the spatial coordinates of multiple first measurement points of the first virtual cross-section S1 can be obtained, and thus the spatial coordinates of the geometric center of the first virtual cross-section S1 can be obtained through the spatial coordinates of the multiple first measurement points.

[0068] In some examples, the multiple first measurement points may include at least five first measurement points. For example, the number of first measurement points can be 5, 6, 7, 8, 9, 10, 20, or 50, etc. In this case, enough first measurement points can be obtained to obtain the spatial coordinates of the geometric center of the first virtual cross-section S1, and the determination error of the spatial coordinates can be reduced.

[0069] In some examples, as described above, the first rotation axis 11 can be rotated to cause the second rotation axis 23 to rotate by a first preset angle, and the second rotation axis 23 can be intercepted using the first section A to obtain the second virtual section S2. In some examples, the first preset angle can be an odd multiple of 180°. In this case, the second virtual section S2 can be obtained. In some examples, obtaining the spatial coordinates of the geometric center of the second virtual section S2 through the first section A is similar to obtaining the spatial coordinates of the geometric center of the first virtual section S1 through the first section A, and will not be described again here.

[0070] In some examples, the vertical error can be calculated based on the positions of the geometric centers of the first virtual cross-section S1 and the second virtual cross-section S2. In some examples, the vertical error can be obtained based on the distance between the geometric centers of the first virtual cross-section S1 and the second virtual cross-section S2.

[0071] In some examples, the distance from the axis of the first rotation axis 11 to the first section A can be obtained, and the vertical error can be obtained based on the distance from the axis of the first rotation axis 11 to the first section A and based on the distance between the geometric centers of the first virtual section S1 and the second virtual section S2.

[0072] In step S200, the vertical error can be adjusted. If the vertical error is not less than a first preset value, the relative position of the first bearing 211 and the first support 21 or the relative position of the second bearing 221 and the second support 22 is adjusted to adjust the angle between the axis of the first rotating shaft 11 and the axis of the second rotating shaft 23. In this case, the vertical error can be effectively reduced.

[0073] In some examples, when adjusting the relative position of the first bearing 211 and the first support 21, the first positioning screw can be loosened and the first bearing 211 adjusted based on vertical error or non-planar error, and the first positioning screw can be tightened after adjusting the relative position of the first bearing 211 and the first support 21. In some examples, when adjusting the relative position of the second bearing 221 and the second support 22, the second positioning screw can be loosened and the second bearing 221 adjusted based on vertical error or non-planar error, and the second positioning screw can be tightened after adjusting the relative position of the second bearing 221 and the second support 22. In this case, the positional relationship between the first rotating shaft 11 and the second rotating shaft 23 can be adjusted by adjusting the positions of the first bearing 211 and / or the second bearing 221.

[0074] In some examples, if the vertical error is not less than a first preset value, the position of the first bearing 211 or the second bearing 221 can be adjusted in the direction of the axis of the first rotating shaft 11. In some examples, if the vertical error is the vertical distance between the two ends of the second rotating shaft 23 and the vertical error is 5 micrometers, the first bearing 211 (or the second bearing 221) can be moved 5 micrometers in the vertical direction. In this case, the position of the first bearing 211 (or the second bearing 221) can be adjusted according to the vertical error to reduce the vertical error.

[0075] In step S300, the non-planar error can be measured.

[0076] Figure 9 This is a schematic diagram showing the spatial coordinates of the geometric center of the third virtual section S3 as described in this disclosure. Figure 10 This is a schematic diagram showing the spatial coordinates of the geometric center of the fourth virtual section S4 as described in this disclosure.

[0077] In some examples, the non-planarity error reflects the distance between the axis of the first rotation axis 11 and the axis of the second rotation axis 23. In some examples, the non-planarity error can be the translation distance of translating the axis of the first rotation axis 11 to the plane containing the axis of the second rotation axis 23. In some examples, the non-planarity error can be the distance between the intersection of the axis of the second rotation axis 23 and the second section B (i.e., the geometric center of the third virtual section S3) and the intersection of the axis of the second rotation axis 23 and the second section B after rotating the first rotation axis 11 by an odd multiple of 180° (i.e., the geometric center of the fourth virtual section S4).

[0078] In some examples, such as Figure 9 and Figure 10As shown, when measuring the non-planar error, the second rotating shaft 23 can be intercepted using a second section B at a second preset distance from the axis of the first rotating shaft 11 to obtain a third virtual section S3. After rotating the first rotating shaft 11 by a first preset angle, the second rotating shaft 23 can be intercepted using the second section B to obtain a fourth virtual section S4.

[0079] In some examples, when measuring the non-planar error, the coordinate measuring instrument 1 can be placed on the bearing surface 4, and the levelness of the bearing surface 4 can be less than a first preset threshold.

[0080] In some examples, when the second section B cuts the second rotation axis 23 to obtain the third virtual section S3, the spatial coordinates of each measurement point (third measurement point) of the third virtual section S3 can be obtained using the measuring instrument 41.

[0081] In some examples, the second section B can be perpendicular to the bearing surface 4. In this case, when the measuring instrument 41 obtains the spatial coordinates of each measuring point (third measuring point) of the third virtual section S3, the measuring instrument 41 can move in a plane, thereby reducing the degree of freedom of the measuring instrument 41 in one direction, thus reducing the error introduced when the measuring instrument 41 moves in that direction, and thus improving the measurement accuracy.

[0082] In some examples, the spatial coordinates of multiple third measurement points of the third virtual cross-section S3 can be obtained using the measuring instrument 41. For instance, the probe of the measuring instrument 41 can be rotated one revolution around the third virtual cross-section S3 within the second cross-section B, and the spatial coordinates of multiple third measurement points on the edge of the third virtual cross-section S3 can be measured. Alternatively, the probe of the measuring instrument 41 can be rotated multiple revolutions around the third virtual cross-section S3 within the first cross-section A, and the spatial coordinates of multiple third measurement points on the edge of the third virtual cross-section S3 can be measured. In this case, the spatial coordinates of multiple third measurement points of the first virtual cross-section S1 can be obtained, and thus the spatial coordinates of the geometric center of the third virtual cross-section S3 can be obtained through the spatial coordinates of the multiple third measurement points.

[0083] In some examples, multiple third measurement points may include at least five third measurement points. For example, the number of third measurement points can be 5, 6, 7, 8, 9, 10, 20, or 50, etc. In this case, enough third measurement points can be obtained to obtain the spatial coordinates of the geometric center of the third virtual section S3, and the determination error of these spatial coordinates can be reduced.

[0084] In some examples, the first rotation axis 11 can be rotated to cause the second rotation axis 23 to rotate by a first preset angle, and the second section B can be used to intercept the second rotation axis 23 to obtain a fourth virtual section S4. As mentioned above, the first preset angle can be an odd multiple of 180°.

[0085] In some examples, obtaining the spatial coordinates of the geometric center of the fourth virtual section S4 through the second section B is similar to obtaining the spatial coordinates of the geometric center of the third virtual section S3 through the second section B, and will not be repeated here.

[0086] In some examples, after obtaining the spatial coordinates of the geometric centers of the third virtual section S3 and the fourth virtual section S4, the skewness error can be calculated based on their geometric centers. Specifically, the distance between the geometric centers of the third virtual section S3 and the fourth virtual section S4 can be calculated as the skewness error.

[0087] In some examples, when obtaining the third virtual cross-section S3, there is a second preset angle between the second rotation axis 23 and the second cross-section B. In some examples, the second preset angle can be any angle not greater than 90°. For example, the second preset angle can be 20°, 30°, 45°, or 90°, etc. In this case, the distance between the geometric centers of the third virtual cross-section S3 and the fourth virtual cross-section S4 can be greater than or equal to twice the distance between the axis of the first rotation axis 11 and the axis of the second rotation axis 23. This allows a larger value to reflect the distance between the axis of the first rotation axis 11 and the axis of the second rotation axis 23, improving measurement accuracy.

[0088] In step S400, the non-planar error can be adjusted.

[0089] In some examples, if the misalignment error is not less than a second preset value, the relative positions of the first bearing 211 and the first support 21, and the relative positions of the second bearing 221 and the second support 22, can be adjusted to adjust the distance between the axis of the first rotating shaft 11 and the axis of the second rotating shaft 23. In this case, the misalignment error can be reduced.

[0090] In some examples, if the non-plane error is the translation distance of the plane containing the axis of the first rotation axis 11 to the plane containing the axis of the second rotation axis 23, the distance that the first bearing 211 and the second bearing 221 need to be adjusted can be obtained directly from the non-plane error. For example, if the non-plane error is 5 micrometers, the first bearing 211 and the second bearing 221 can be adjusted at the same time, and the first bearing 211 and the second bearing 221 can be moved 5 micrometers along a direction orthogonal to the axis of the first rotation axis 11 and the axis of the second rotation axis 23.

[0091] In some examples, the non-planar error is the distance between the intersection of the axis of the second rotation axis 23 and the second section B (i.e., the geometric center of the third virtual section S3) and the intersection of the axis of the second rotation axis 23 and the second section B after the first rotation axis 11 has been rotated by an odd multiple of 180° (i.e., the geometric center of the fourth virtual section S4). Therefore, the translation distance of the axis of the first rotation axis 11 to the plane containing the axis of the second rotation axis 23 can be calculated based on the non-planar error, and the positions of the first bearing 211 and the second bearing 221 can be adjusted accordingly.

[0092] In some examples, the distance between the axis of the first rotating shaft 11 and the axis of the second rotating shaft 23 can be adjusted using an alternative method. For instance, in some examples, if the misalignment error is not less than a second preset value, the relative position of the second rotating device 20 and the first rotating device 10 is adjusted to adjust the distance between the axes of the first rotating shaft 11 and the second rotating shaft 23. Specifically, the second rotating device 20 can be engaged with the first rotating shaft 11 via a translation mechanism (not shown), which has a slide rail, and the second rotating device 20 can be moved relative to the first rotating shaft 11 (first rotating device 10) along the slide rail direction by adjusting the translation mechanism. In this case, the influence of adjusting the first bearing 211 and the second bearing 221 on the vertical error can be avoided.

[0093] In step S500, the vertical error can be repeatedly adjusted to make it less than a first preset value. In step S600, the non-planar error can be repeatedly adjusted to make it less than a second preset value. In this way, the influence of other errors introduced when adjusting the vertical and non-planar errors on the orthogonal axis system can be reduced, and the accuracy of the calibration method can be improved.

[0094] In some examples, when the vertical error is less than a first preset value and the non-planar error is less than a second preset value, the first bearing 211 and the second bearing 221 are fixed. In this case, the adjusted vertical error and non-planar error can be fixed, and the relative positional relationship between the first rotating shaft 11 and the second rotating shaft 23 can be fixed.

[0095] Various embodiments of the invention have been described above in detail. Although these descriptions directly depict the above embodiments, it should be understood that modifications and / or variations to the specific embodiments shown and described herein will occur to those skilled in the art. Any such modifications or variations falling within the scope of this specification are also intended to be included herein. Unless specifically indicated, the inventors intend that the words and phrases in the specification and claims be given the common and customary meaning to those skilled in the art.

[0096] The above description of various embodiments of the invention known to the applicant at the time of filing this application is intended for illustrative and descriptive purposes. This description is not intended to be exhaustive, nor does it limit the invention to the exact forms disclosed, and many modifications and variations can be made based on the foregoing teachings. The described embodiments are intended to explain the principles of the invention and its practical application, and to enable others skilled in the art to utilize the invention in various embodiments and with various modifications suitable for the intended particular use. Therefore, the invention is not intended to be limited to the specific embodiments disclosed for implementing the invention.

[0097] While specific embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that variations and modifications can be made based on the teachings of the invention without departing from the invention and its broader aspects, and therefore the appended claims are intended to cover all such changes and modifications within the true spirit and scope of the invention. Those skilled in the art will understand that, in general, the terminology used in this invention is intended to be “open” terminology (e.g., the term “comprising” should be interpreted as “including but not limited to”, the term “having” should be interpreted as “at least having”, the term “comprising” should be interpreted as “including but not limited to”, etc.).

Claims

1. A method for adjusting an orthogonal axis system, characterized in that, The orthogonal axis system includes a first rotation axis and a second rotation axis that can rotate around the first rotation axis. The adjustment method includes: intercepting the second rotation axis with a second cross section at a second preset distance from the axis of the first rotation axis to obtain a third virtual cross section; rotating the first rotation axis to rotate the second rotation axis by a first preset angle, and intercepting the second rotation axis with the second cross section to obtain a fourth virtual cross section; calculating a non-planar error reflecting the distance between the axis of the first rotation axis and the axis of the second rotation axis based on the geometric center of the third virtual cross section and the geometric center of the fourth virtual cross section; if the non-planar error is not less than a second preset value, adjusting the relative position of the axis of the first rotation axis and the axis of the second rotation axis based on the non-planar error to reduce the non-planar error; The spatial coordinates of multiple third measurement points of the third virtual cross section are obtained, and the spatial coordinates of the geometric center of the third virtual cross section are obtained based on the spatial coordinates of the multiple third measurement points, wherein the multiple third measurement points are located at the edge of the third virtual cross section; the spatial coordinates of multiple fourth measurement points of the fourth virtual cross section are obtained, and the spatial coordinates of the geometric center of the fourth virtual cross section are obtained based on the spatial coordinates of the multiple fourth measurement points, wherein the multiple fourth measurement points are located at the edge of the fourth virtual cross section; and the non-planar error is calculated based on the spatial coordinates of the geometric center of the third virtual cross section and the spatial coordinates of the geometric center of the fourth virtual cross section. The calibration method further includes: using a first cross-section spaced a first preset distance from the axis of the first rotating axis to cut the second rotating axis to obtain a first virtual cross-section; rotating the first rotating axis to rotate the second rotating axis by the first preset angle, and using the first cross-section to cut the second rotating axis to obtain a second virtual cross-section; calculating a vertical error based on the position of the geometric center of the first virtual cross-section and the position of the geometric center of the second virtual cross-section, the vertical error reflecting the angle between the axis of the first rotating axis and the axis of the second rotating axis; and if the vertical error is not less than a first preset value, adjusting the relative position of the axis of the first rotating axis and the axis of the second rotating axis based on the vertical error to reduce the vertical error.

2. The calibration method for the orthogonal axis system according to claim 1, characterized in that: It also includes repeatedly adjusting the non-planar error to make the non-planar error less than the second preset value.

3. The calibration method for the orthogonal axis system according to claim 1, characterized in that: When the third virtual cross section is obtained, there is a second preset angle of no more than 90 degrees between the second rotation axis and the second cross section.

4. The calibration method for the orthogonal axis system according to claim 1, characterized in that: It also includes repeatedly adjusting the vertical error to make the vertical error less than the first preset value.

5. The calibration method for the orthogonal axis system according to claim 4, characterized in that: The spatial coordinates of multiple first measurement points of the first virtual cross section are obtained, and the spatial coordinates of the geometric center of the first virtual cross section are obtained based on the spatial coordinates of the multiple first measurement points, wherein the multiple first measurement points are located at the edge of the first virtual cross section; the spatial coordinates of multiple second measurement points of the second virtual cross section are obtained, and the spatial coordinates of the geometric center of the second virtual cross section are obtained based on the spatial coordinates of the multiple second measurement points, wherein the multiple second measurement points are located at the edge of the second virtual cross section; and the vertical error is calculated based on the spatial coordinates of the geometric center of the first virtual cross section and the spatial coordinates of the geometric center of the second virtual cross section.

6. The calibration method for the orthogonal axis system according to claim 1, characterized in that: The first preset angle is an odd multiple of 180 degrees.

7. A coordinate measuring device, the coordinate measuring device comprising an orthogonal axis system having a first rotation axis and a second rotation axis rotatable about the first rotation axis, characterized in that, The coordinate measuring instrument uses the calibration method of the orthogonal axis system as described in any one of claims 1 to 6 to calibrate the relative positions of the first rotation axis and the second rotation axis.

8. The coordinate measuring device according to claim 7, characterized in that: The coordinate measuring instrument includes a first rotating device having a first rotating axis and a second rotating device disposed on the first rotating device and having a second rotating axis. The second rotating device includes a first support portion, a first bearing disposed on the first support portion, a second support portion, and a second bearing disposed on the second support portion. The second rotating axis is mounted on the second rotating device via the first bearing and the second bearing. The relative position of the axis of the first rotating axis and the axis of the second rotating axis can be adjusted by adjusting the relative position of the first bearing and the first support portion or the relative position of the second bearing and the second support portion.

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