CN114396901A

Movatterモバイル変換

Info

Publication number: CN114396901A
Application number: CN202210085559.3A
Authority: CN
Inventors: 张和君; 廖学文; 陈源; 常立超
Original assignee: Chotest Technology Inc
Current assignee: Chotest Technology Inc
Priority date: 2021-11-18
Filing date: 2021-11-18
Publication date: 2022-04-26
Also published as: CN113790689A; CN113790689B; CN114396902A

Abstract

The invention describes a space coordinate measuring instrument which is configured to measure the space coordinate of an auxiliary measuring device and calibrate the error of the space coordinate measuring instrument by using the auxiliary measuring device, wherein the calibration method comprises the following steps: measuring the actual length of the standard rod as a first length measurement value; fixing the standard rod in a mode of being vertical to the bearing surface, and measuring the length of the standard rod to obtain a second length measurement value; fixing the standard rod in a mode of being parallel to the bearing surface, and measuring the length of the standard rod to obtain a third length measurement value; calibrating a reference distance error value matched with the reference distance based on the first length measurement value and the second length measurement value; and the line spacing between the axis of the first rotating shaft and the axis of the second rotating shaft is used as a non-coplanar error value, and the non-coplanar error value is calibrated based on the first length measurement value, the third length measurement value and the reference distance error value. According to the present invention, a spatial coordinate measuring instrument capable of improving the comprehensive measurement accuracy can be provided.

Description

Space coordinate measuring instrument

The application is a divisional application of patent application with the application date of 2021, 11/18, the application number of 202111367247.3, and the name of the invention being a calibration method of a space coordinate measuring instrument.

Technical Field

The present invention relates generally to the intelligent manufacturing equipment industry, and more particularly to spatial coordinate measuring instruments.

Background

In an optical precision coordinate measuring instrument, a plurality of optical errors and structural errors are often introduced in the processing and assembling process of the instrument, such as light speed inclination errors, light beam offset errors, two-axis different plane errors, base distance errors and the like. The introduction of these optical errors and structural errors can cause errors in the coordinate measuring system of the instrument, and ultimately affect the overall measurement accuracy of the instrument. In addition, the above-mentioned errors are also introduced when the instrument is collided during long-distance transportation or measurement or weather parameters of the measurement environment are largely changed. The traditional error calibration usually needs to return the coordinate measuring instrument to a laboratory for calibration, a complex standard instrument is needed for calibrating the coordinate measuring instrument, and the calibration method is often complicated in steps and time-consuming.

The invention calibrates the laser tracker based on the length standard device, and then uses the observed quantity of the calibrated point to perform error correction on the observed quantity of the target point actually measured by the laser tracker, thereby improving the measurement precision of the laser tracker. Although the method can improve the measurement accuracy of the laser tracker, the data required to be measured is excessive, so that the measurement steps are correspondingly excessive and complicated, and a large error is introduced in the measurement process. Furthermore, the calculation of the number of index point corrections is too complex and cumbersome. The introduction of a plurality of measurement errors and calculation errors will have a great influence on the comprehensive measurement accuracy of the laser tracker.

Disclosure of Invention

The present invention has been made in view of the above-described conventional circumstances, and an object thereof is to provide a calibration method capable of improving the overall measurement accuracy of a spatial coordinate measuring apparatus.

To this end, a first aspect of the present invention provides a calibration method of a spatial coordinate measuring apparatus configured to measure spatial coordinates of an auxiliary measuring device, the spatial coordinate measuring apparatus including a first rotating device having a first rotating axis and a reference portion, and a second rotating device provided to the first rotating device and having a second rotating axis, the first rotating axis being orthogonal to the second rotating axis, characterized by comprising: measuring the actual length of the standard rod as a first length measurement value; placing the space coordinate measuring instrument on a supporting device positioned on a bearing surface, wherein the first rotating shaft is vertical to the bearing surface; fixing the standard rod in a mode of being perpendicular to the bearing surface, and measuring the length of the standard rod through the space coordinate measuring instrument to obtain a second length measurement value; fixing the standard rod in a mode of being parallel to the bearing surface, and measuring the length of the standard rod through the space coordinate measuring instrument to obtain a third length measurement value; and setting the intersection point of the axis of the second rotating shaft, which passes through the axis of the second rotating shaft and is parallel to the bearing surface, and the axis of the first rotating shaft as the central position of the space coordinate measuring instrument, setting the distance between the central position and the reference part as a reference distance, calibrating a reference distance error value matched with the reference distance based on the first length measurement value and the second length measurement value, setting the line distance between the axis of the first rotating shaft and the axis of the second rotating shaft as an out-of-plane error value, and calibrating the out-of-plane error value of the first rotating shaft and the second rotating shaft based on the first length measurement value, the third length measurement value and the reference distance error value.

In the calibration method, firstly, the actual length value of the standard rod is measured to be used as a first length measurement value, a second length measurement value of the standard rod in the direction perpendicular to the bearing surface and a third length measurement value of the standard rod in the direction parallel to the bearing surface are measured by the space coordinate measuring instrument, then, the reference distance error value of the space coordinate measuring instrument is calibrated based on the first length measurement value and the second length measurement value, and the different-surface error value of the space coordinate measuring instrument can be calibrated based on the first length measurement value, the third length measurement value and the reference distance error value. Under the condition, the error of the coordinate measuring system is calibrated without returning to a laboratory, but the reference distance error value and the heterofacial error value of the space coordinate measuring instrument can be reversely calibrated on the measuring site of the space coordinate measuring instrument through simple measuring steps, and then the coordinate measuring system is corrected by utilizing the system compensation model to improve the comprehensive measuring precision of the space coordinate measuring instrument and simultaneously improve the measuring efficiency of the space coordinate measuring instrument.

In the calibration method according to the first aspect of the present invention, optionally, the reference lever includes a first end portion and a second end portion, and the coordinate values of the first end portion and the second end portion are measured by sequentially arranging the auxiliary measuring device at the first end portion and the second end portion. In this case, the second length measurement value of the master lever, that is, the longitudinal length measurement value, may be obtained based on the coordinate values of the first end portion and the second end portion.

In the calibration method according to the first aspect of the present invention, the first end and the second end may be located at equal distances from the center position. Under the condition, the rotation angle of the space coordinate measuring instrument in the measuring process can be conveniently measured, and the subsequent calibration calculation of errors is facilitated.

Further, in the calibration method according to the first aspect of the present invention, optionally, the average value of the second measured length values and the average value of the third measured length values are obtained by measuring the coordinate values of the first end portion and the second end portion a plurality of times. In this case, the measurement error of the spatial coordinate measuring apparatus can be reduced by measuring enough data to obtain an accurate second length measurement value.

In addition, in the calibration method according to the first aspect of the present invention, optionally, a difference between the first measured length value and the second measured length value is a first error value, and if the first error value is greater than a second preset value, the reference distance error value is calibrated based on the first error value, so that the coordinate measurement system of the spatial coordinate measurement apparatus is corrected by using a system compensation model. Under the condition, the base distance error value can be calibrated reversely based on the difference value of the first length measurement value and the second length measurement value, and then the measurement error of the space coordinate measuring instrument can be compensated in real time to improve the measurement precision.

In addition, in the calibration method according to the first aspect of the present invention, optionally, a difference between the first measured length value and the third measured length value is made to be a second error value, and if the first error value is greater than the second preset value or the second error value is greater than the third preset value, the out-of-plane error value is calibrated, and then the system compensation model is used to correct the coordinate measurement system of the spatial coordinate measurement apparatus. Under the condition, whether the space coordinate measuring instrument meets the measuring precision requirement is judged by setting a certain error range, and if not, the out-of-plane error can be calibrated in time so as to improve the measuring precision of the measuring instrument.

In addition, in the calibration method according to the first aspect of the present invention, optionally, a sum of the reference distance error value and the out-of-plane error value is obtained based on the second error value, and the out-of-plane error value is obtained based on the reference distance error value. In this case, a specific magnitude of the out-of-plane error value can be obtained by calculation.

In addition, in the calibration method according to the first aspect of the present invention, optionally, the reference portion is an initial placement point of the auxiliary measuring device, and the auxiliary measuring device is placed on the reference portion to initialize the spatial coordinate measuring device before the spatial coordinate measuring device measures the length of the standard bar. In this case, the origin of coordinates of the spatial coordinate measuring apparatus can be initialized.

In the calibration method according to the first aspect of the present invention, the standard bar may be equal in height to the spatial coordinate measuring instrument when the standard bar is fixed parallel to the bearing surface. In this case, interference of other structural errors can be eliminated, and the measurement accuracy of the spatial coordinate measuring instrument is more accurate.

In addition, in the calibration method according to the first aspect of the present invention, optionally, the standard rod is a standard indium tile ruler, a standard carbon fiber or a guide rail including a laser interferometer, and the first length measurement value is measured by a dual-frequency interferometer or a three-coordinate measuring instrument. In this case, based on the high-precision measuring tool or the length standard gauge, the measuring instrument with the high-precision measuring function measures the standard rod, so that the measurement result is closest to the true value, that is, the measurement result is the true value of the standard rod.

According to the calibration method provided by the invention, the comprehensive measurement precision of the space coordinate measuring instrument can be improved by utilizing the system compensation model through calibrating the specific magnitude of the error.

Drawings

The invention will now be explained in further detail by way of example only with reference to the accompanying drawings.

Fig. 1A is a perspective view showing a spatial coordinate measuring apparatus according to an example of the present invention.

Fig. 1B is a perspective view showing a spatial coordinate measuring apparatus according to an example of the present invention when an auxiliary measuring device is placed.

Fig. 2A is a simplified schematic diagram illustrating a first rotating device and a second rotating device in accordance with an example of the present invention.

Fig. 2B is a simplified schematic diagram illustrating a first rotation axis and a second rotation axis according to an example of the present invention.

FIG. 3 is a schematic diagram showing a first measured length of a master rod according to an example of the present invention.

Fig. 4A is a scene diagram illustrating a second measured value according to an example of the present invention.

Fig. 4B is a front view showing a time when the second measured length value is measured according to an example of the present invention.

Fig. 5A is a scene diagram illustrating a third measured value according to an example of the present invention.

Fig. 5B is a top view illustrating the measurement of a third measured length value according to an example of the present invention.

Fig. 6 is a schematic diagram showing a reference distance according to an example of the present invention.

FIG. 7 is a schematic diagram illustrating a center position and out-of-plane errors in accordance with an example of the present invention.

FIG. 8 is a flow chart illustrating a calibration method according to an example of the present invention.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same components are denoted by the same reference numerals, and redundant description thereof is omitted. The drawings are schematic and the ratio of the dimensions of the components and the shapes of the components may be different from the actual ones.

It is noted that, as used herein, the terms "comprises," "comprising," or any other variation thereof, such that a process, method, system, article, or apparatus that comprises or has a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include or have other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In addition, the subtitles and the like referred to in the following description of the present invention are not intended to limit the content or the scope of the present invention, and serve only as a cue for reading. Such a subtitle should neither be understood as a content for segmenting an article, nor should the content under the subtitle be limited to only the scope of the subtitle.

The invention provides a calibration method of a space coordinate measuring instrument, wherein the space coordinate measuring instrument is configured to measure the space coordinate of an auxiliary measuring device. In some examples, the spatial coordinate measuring apparatus may include a first rotating device having a first rotating axis and a reference part, and a second rotating device provided to the first rotating device and having a second rotating axis, the first rotating axis being orthogonal to the second rotating axis.

In some examples, the calibration method may include: measuring the actual length of the standard rod as a first length measurement value; placing the space coordinate measuring instrument on a supporting device positioned on a bearing surface, wherein the first rotating shaft is vertical to the bearing surface; fixing the standard rod in a mode of being perpendicular to the bearing surface, and measuring the length of the standard rod through the space coordinate measuring instrument to obtain a second length measurement value; and fixing the standard rod in a mode of being parallel to the bearing surface, and measuring the length of the standard rod by the space coordinate measuring instrument to obtain a third length measurement value. In this case, it is possible to measure the actual length value of the master rod as a first length measurement value, and a second length measurement value of the master rod in the direction perpendicular to the bearing surface and a third length measurement value of the master rod in the direction parallel to the bearing surface, which are measured by the spatial coordinate measuring instrument.

In some examples, an intersection point of a virtual plane passing through the axis of the second rotation shaft and parallel to the bearing surface and the axis of the first rotation shaft may be made a center position of the spatial coordinate measuring apparatus, a distance between the center position and the reference part may be made a reference distance, and the reference distance error value may be calibrated based on the first length measurement value and the second length measurement value. In some examples, a line spacing of the axes of the first and second rotating shafts may be made an out-of-plane error value, and the out-of-plane error value of the first and second rotating shafts may be calibrated based on the first measured length value, the third measured length value, and the reference distance error value. In this case, the reference distance error value of the space coordinate measuring apparatus can be calibrated based on the first measured length value and the second measured length value, and the out-of-plane error value of the space coordinate measuring apparatus can be calibrated based on the first measured length value, the third measured length value, and the reference distance error value.

Fig. 1A is a schematic perspective view showing a spatial coordinate measuringapparatus 1 according to an example of the present invention. Fig. 1B is a perspective view showing a spatial coordinate measuringapparatus 1 according to an example of the present invention when anauxiliary measuring device 2 is placed.

In the present embodiment, as shown in fig. 1A, the spatial coordinate measuringapparatus 1 may include a firstrotating device 11, areference part 112, and a secondrotating device 12.

In some examples, thereference portion 112 may be provided at the outer periphery of the firstrotating device 11.

In some examples, thereference portion 112 may have a reference surface, which may be configured to place an auxiliary measuring device 2 (described later). In some examples, thereference portion 112 may also be referred to as a "bird nest.

In some examples, the reference plane may have a reference distance position a located at a center of the reference plane and having a groove shape. Specifically, thereference part 112 may be an initial placement point of theauxiliary measuring device 2, and theauxiliary measuring device 2 may be placed on thereference part 112 to initialize the spatial coordinate measuringapparatus 1 before the spatial coordinate measuringapparatus 1 measures the length of a standard pole 3 (described later). In this case, the origin of coordinates of the spatial coordinate measuringapparatus 1 can be initialized. In some examples, the location of thereference portion 112 where theauxiliary measuring device 2 is placed may be a reference distance position a.

In some examples, thereference portion 112 may be a prism. Specifically, as shown in fig. 1A, thereference portion 112 may be disposed outside the firstrotating device 11. Thereference part 112 may have a first side surface, a second side surface, a third side surface, a fourth side surface, a fifth side surface and a sixth side surface connected in sequence, wherein the first side surface may be a side surface connected to the firstrotating device 11, and the fourth side surface may be a reference surface. The present invention is not limited thereto, and the reference plane may be connected with the firstrotating device 11 by other means, including but not limited to, by a mechanical arm, by a bracket, or by at least one pillar, etc.

In some examples, thereference portion 112 is detachably provided to the firstrotating device 11. In other examples, thereference portion 112 and the firstrotating device 11 may be integrally formed.

In some examples, theauxiliary measuring device 2 may be referred to as an "attitude target ball", "attitude target", "target", or "target ball", and the spatial coordinate measuringapparatus 1 relating to the present embodiment may track theauxiliary measuring device 2 and measure the spatial coordinates of theauxiliary measuring device 2. As shown in fig. 1B, in some examples, theauxiliary measuring device 2 may be a spherical structure, and a hollow corner cube may be embedded inside the spherical structure to reflect the laser light. In this case, the spatial coordinate measuringapparatus 1 can obtain the spatial coordinates of theauxiliary measuring device 2 from the incident laser light and the reflected laser light.

Fig. 2A is a simplified schematic diagram illustrating a firstrotating device 11 and a secondrotating device 12 according to an example of the present invention. Fig. 2B is a simplified schematic diagram illustrating thefirst rotation shaft 111 and thesecond rotation shaft 121 according to an example of the present invention.

In some examples, thesecond rotation device 12 may have a support portion including afirst support portion 122 and asecond support portion 123, and through holes are provided on thefirst support portion 122 and thesecond support portion 123, respectively. Specifically, thefirst support part 122 may have a first throughhole 124, and thesecond support part 123 may have a second throughhole 125.

In some examples, thesecond rotation device 12 may be disposed above thefirst rotation device 11 and may rotate about thefirst rotation device 11. Thereby, the secondrotating device 12 can rotate following the rotation of the firstrotating device 11. In some examples, the firstrotating device 11 may be rotated by a driving device (not shown), such as a driving motor, to drive the firstrotating shaft 111 to rotate. In some examples, thefirst rotation shaft 111 may be mounted to thefirst rotation device 11, and thesecond rotation shaft 121 may be mounted to thesecond rotation device 12. In some examples, thefirst rotation axis 111 and thesecond rotation axis 121 may be orthogonal to constitute an orthogonal axis system of the spatial coordinate measuringapparatus 1. In this case, based on thefirst rotation axis 111 and thesecond rotation axis 121 being orthogonal, the measurement accuracy of the spatial coordinate measuringapparatus 1 can be improved. In some examples, thesecond rotation shaft 121 may be installed between the first and

second support parts

122 and 123 through the first and second through

holes

124 and 125.

Fig. 3 is a schematic diagram showing a first measured length L1 of amaster lever 3 according to an example of the present invention.

In the calibration method according to the present embodiment, onemaster rod 3 may be prepared in advance, and the actual length of themaster rod 3 may be measured as the first measured length L1. In some examples, the first measured length value L1 of themaster lever 3 may be measured in advance in a laboratory. Therefore, error correction of the spatial coordinate measuringinstrument 1 by using the first length measurement value of thestandard rod 3 at the measuring site is facilitated.

In some examples, themaster lever 3 may be machined with high precision. Thereby, themaster rod 3 can be obtained with high accuracy to reduce subsequent measurement errors. In some examples, thestandard bar 3 may be an elongated rectangular parallelepiped. In other examples, themodular rods 3 may be elongated cylindrical or polygonal prism shaped.

In some examples, the first measured length value L1 may be the actual length value of themaster lever 3, and may also be referred to as the theoretical value of themaster lever 3. In some examples, the first length measurement value L1 may be obtained by a precision gauge (not shown) having precision measurement performance or a high-precision length-reference ruler (not shown), for example, a standard indium tile ruler, a standard carbon fiber rod, or a guide rail measurement including a laser interferometer, and the measurement error of the precision gauge and the high-precision length-reference ruler may reach the micrometer level. In this case, since the measurement error of themaster bar 3 by the precision gauge and the length-reference gauge is very small, the measurement result can be considered to be the actual length value of themaster bar 3.

In some examples, the actual length of theetalon 3 may be measured using a guide rail and laser interferometer in a laboratory with constant meteorological parameters. In some examples, the actual length of thegauge bar 3 may be measured at the laser tracker measurement site using a standard indium tile ruler or a standard carbon fiber rod.

In some examples, theetalon 3 may preferably be a precision gauge or a length-scale machined with high precision, for example theetalon 3 may be a standard indium tile ruler, a standard carbon fibre or a guide rail containing a laser interferometer. In some examples, thereference bar 3 may be measured by a dual-frequency interferometer or a three-coordinate measuring instrument to obtain the first measured length value L1. In this case, the measuring result can be made closest to the true value, that is, the measured result is the true value of themaster rod 3, by measuring themaster rod 3 with the measuring instrument having the high-precision measuring function based on the high-precision measuring tool or the length scale.

In the calibration method according to the present embodiment, in order to obtain the measured length of the spatial coordinate measuringapparatus 1 measuring thestandard rod 3, the spatial coordinate measuringapparatus 1 may be first placed on the supporting device 4, and the supporting device 4 may be located on a carrying surface (not shown). In some examples, a movable pulley or roller may be mounted below the support means 4. Thereby, the movement of the spatial coordinate measuringapparatus 1 can be facilitated. In some examples, thefirst rotation axis 111 of the spatial coordinate measuringapparatus 1 may be perpendicular to the bearing surface. In some examples, if thefirst rotation axis 111 is not perpendicular to the bearing surface, the spatial coordinate measuringapparatus 1 may be adjusted by an adjusting mechanism (not shown) or an adjusting method to keep thefirst rotation axis 111 perpendicular to the bearing surface. In this case, the measurement accuracy of the spatial coordinate measuringapparatus 1 can be improved.

In some examples, the bearing surface may be a smooth floor. In some examples, the bearing surface may be a horizontal plane. Therefore, the supporting device 4 can be kept on the bearing surface in a stable state, and the horizontal state of the space coordinate measuringapparatus 1 is further kept. In some examples, the deviation of the flatness of the bearing surface may be less than a first preset value. In some examples, the first preset value may be 1 to 10 microns. For example, the first preset value may be 1 micron, 2 microns, 3 microns, 4 microns, 5 microns, 6 microns, 7 microns, 8 microns, 9 microns, 10 microns, or the like. In some examples, the smaller the deviation of the bearing surface levelness, the smaller the measurement error of the spatial coordinate measuringapparatus 1 will be.

Fig. 4A is a scene diagram illustrating a second measured length L2 according to an example of the present invention. Fig. 4B is a front view showing a time when the second measured length value L2 is measured according to an example of the present invention.

In some examples, the second measured length value L2 may be obtained by measuring the length of thestandard bar 3 in the vertical direction by the spatial coordinate measuringinstrument 1. In some examples, the second length measurement value L2 may also be referred to as a longitudinal length measurement value of the spatial coordinate measuringapparatus 1. In some examples, the vertical direction may be a direction perpendicular to the bearing surface. In other examples, the vertical direction may be a direction parallel to the axis of thefirst rotation shaft 111.

In some examples, thestandard bar 3 may be fixed in front of the spatial coordinate measuringapparatus 1 in a manner perpendicular to the bearing surface. Thereby, the spatial coordinate measuringapparatus 1 can measure thestandard rod 3. In other examples, thestandard rod 3 may be fixed in front of the spatial coordinate measuringapparatus 1 in a manner parallel to the axis of the firstrotating shaft 111.

In some examples, thestandard rod 3 may be fixed in front of the spatial coordinate measuringapparatus 1 in an attitude perpendicular to the bearing surface by a fixing mechanism (not shown). In some examples, thestandard rod 3 may be fixed right in front of the spatial coordinate measuringapparatus 1. In some examples, the distance in the horizontal direction of thestandard bar 3 and the spatial coordinate measuringinstrument 1 may be related to the length of thestandard bar 3. In some examples, the fixing mechanism may be a bracket having a function of fixing thestandard bar 3. In other examples, the fixing mechanism may be other devices having a fixing function. In this case, thestandard bar 3 may be fixed in front of the spatial coordinate measuringapparatus 1 in an attitude perpendicular to the bearing surface.

In some examples, thereference bar 3 may include afirst end 31 and asecond end 32, and the coordinate values of thefirst end 31 and thesecond end 32 may be measured by sequentially disposing theauxiliary measuring device 2 to thefirst end 31 and thesecond end 32. In this case, the second measurement value L2, that is, the longitudinal measurement value of thereference lever 3 can be obtained based on the coordinate values of thefirst end portion 31 and thesecond end portion 32.

Specifically, theauxiliary measuring device 2 may be fixed to thefirst end portion 31 first, and the spatial coordinate measuringinstrument 1 may obtain the coordinate value of thefirst end portion 31 based on theauxiliary measuring device 2; then, theauxiliary measuring device 2 is moved to thesecond end 32, and the spatial coordinate measuringinstrument 1 can obtain the coordinate value of thesecond end 32 based on theauxiliary measuring device 2. In some examples, when thereference bar 3 is fixed in front of the spatial coordinate measuringinstrument 1 in a manner perpendicular to the bearing surface, the coordinate value of thefirst end 31 may be referred to as a first coordinate value, and the coordinate value of thesecond end 32 may be referred to as a second coordinate value. In this case, the measured length of thereference lever 3 in the vertical direction can be obtained as the second measured length value L2, that is, the longitudinal measured length value, based on the first and second coordinate values.

In some examples, when thestandard bar 3 is fixed in front of the spatial coordinate measuringinstrument 1 in a manner perpendicular to the bearing surface, the distances of thefirst end 31 and thesecond end 32 to a center position B (described later) of the spatial coordinate measuringinstrument 1 may be substantially equal. Preferably, the center position B may be flush with themidpoint position 33 of thestandard bar 3, in other words, a line connecting the center position B and themidpoint position 33 of thestandard bar 3 may be perpendicular to thestandard bar 3. Under the condition, the rotation angle of the space coordinate measuringinstrument 1 in the measuring process can be conveniently measured, and the subsequent calibration calculation of errors is convenient.

Fig. 5A is a scene diagram illustrating a third measured length L3 according to an example of the present invention. Fig. 5B is a top view illustrating the measurement of a third measured length value L3 in accordance with an example of the present invention.

In some examples, the third measured length value L3 may be obtained by measuring the length of thereference pole 3 in the horizontal direction by the spatial coordinate measuringinstrument 1. In some examples, the third length measurement value L3 may also be referred to as a lateral length measurement value of the spatial coordinate measuringapparatus 1. In some examples, the horizontal direction may be a direction parallel to the bearing surface. In other examples, the horizontal direction may be a direction perpendicular to the axis of thefirst rotation shaft 111.

In some examples, thestandard bar 3 may be fixed in front of the spatial coordinate measuringapparatus 1 in a manner parallel to the bearing surface. Thereby, the spatial coordinate measuringapparatus 1 can measure thestandard rod 3. In other examples, thestandard rod 3 may be fixed in front of the spatial coordinate measuringapparatus 1 in a manner perpendicular to the axis of the firstrotating shaft 111.

In some examples, thestandard rod 3 may be fixed in front of the spatial coordinate measuringapparatus 1 in an attitude parallel to the bearing surface by a fixing mechanism. In some examples, when thestandard bar 3 is fixed in a manner parallel to the bearing surface, thestandard bar 3 and the spatial coordinate measuringapparatus 1 may be flush with each other. In some examples, when thestandard bar 3 is fixed in a manner parallel to the bearing surface, the center position B of thestandard bar 3 and the spatial coordinate measuringinstrument 1 may be flush with each other. In this case, interference of other structural errors can be eliminated, and the measurement accuracy of the spatial coordinate measuringapparatus 1 can be made more accurate. In some examples, during the measurement of the third measured length value, a line connecting the center position B and themidpoint position 33 of thestandard bar 3 may be perpendicular to thestandard bar 3. In other words, the distances from thefirst end 31 and thesecond end 32 to the center position B of the spatial coordinate measuringapparatus 1 may be equal. Under the condition, the rotation angle of the space coordinate measuringinstrument 1 in the measuring process can be conveniently measured, and the subsequent calibration calculation of errors is convenient.

In some examples, the fixing mechanism may be a bracket having a function of fixing thestandard bar 3. In other examples, the fixing mechanism may be other devices having a fixing function. In this case, thestandard rod 3 may be fixed in front of the spatial coordinate measuringinstrument 1 in an attitude parallel to the bearing surface.

In some examples, when thereference lever 3 is in the horizontal direction, the coordinate values of thefirst end 31 and thesecond end 32 may be measured by sequentially disposing theauxiliary measuring device 2 to thefirst end 31 and thesecond end 32. In this case, the third measurement value L3 of thereference lever 3, that is, the lateral measurement value, can be obtained based on the coordinate values of thefirst end portion 31 and thesecond end portion 32.

Specifically, theauxiliary measuring device 2 may be fixed to thefirst end portion 31 first, and the spatial coordinate measuringinstrument 1 may obtain the coordinate value of thefirst end portion 31 based on theauxiliary measuring device 2; then, theauxiliary measuring device 2 is moved to thesecond end 32, and the spatial coordinate measuringinstrument 1 can obtain the coordinate value of thesecond end 32 based on theauxiliary measuring device 2. Thereby, the coordinate values of the first end portion and the second end portion can be obtained based on the auxiliary measuring device.

In some examples, when thereference bar 3 is fixed in front of the spatial coordinate measuringinstrument 1 in a manner parallel to the bearing surface, the coordinate value of thefirst end 31 may be referred to as a third coordinate value, and the coordinate value of thesecond end 32 may be referred to as a fourth coordinate value. In this case, the measured length of thereference lever 3 in the horizontal direction can be obtained as the third measured length value L3, that is, the lateral measured length value, based on the third coordinate value and the fourth coordinate value.

In some examples, theauxiliary measuring devices 2 may be placed at both ends of themaster bar 3 at the same time. In this case, the coordinate values of thefirst end portion 31 and thesecond end portion 32 can be measured simultaneously, thereby reducing an error introduced by the operation steps.

In the calibration method according to the present embodiment, the average value of the second length value L2 and the average value of the third length value L3 can be obtained by measuring the coordinate values of thefirst end 31 and the second end 32 a plurality of times. Specifically, in some examples, when themaster lever 3 is in the vertical direction, the plurality of second measured length values L2 may be obtained by measuring the first and second coordinate values a plurality of times and based on the plurality of first and second coordinate values, and then calculating the average of the plurality of second measured length values L2. In this case, the measurement error of the spatial coordinate measuringapparatus 1 can be reduced by measuring a sufficient amount of data to obtain the accurate second measured length value L2.

In some examples, when thereference lever 3 is in the horizontal direction, the plurality of third measured length values L3 may be obtained by measuring the third coordinate value and the fourth coordinate value a plurality of times and based on the plurality of third coordinate values and the plurality of fourth coordinate values, and then calculating an average value of the plurality of third measured length values L3. In this case, the accurate third measured length value L3 can be obtained by measuring a sufficient amount of data.

In some examples, the plurality of first coordinate values, the plurality of second coordinate values, the plurality of third coordinate values, and the plurality of fourth coordinate values may be preprocessed, for example, coordinate values in which abnormality is present may be removed. In this case, the measurement errors of the second measurement value L2 and the third measurement value L3 can be reduced.

Fig. 6 is a schematic diagram showing the reference distance L according to the example of the present invention. Fig. 7 is a schematic diagram showing the center position B and the out-of-plane error according to an example of the present invention.

As shown in fig. 7, in the calibration method according to the present embodiment, an intersection point of a virtual plane Z passing through the axis of the secondrotating shaft 121 and parallel to the bearing surface and the axis of the firstrotating shaft 111 may be set as the center position B of the spatial coordinate measuringapparatus 1. In some examples, the axis of the firstrotating shaft 111 may be referred to as afirst axis 1111, and the axis of the secondrotating shaft 121 may be referred to as asecond axis 1211, i.e., an intersection point of a virtual plane Z passing through thesecond axis 1211 and parallel to the bearing surface and thefirst axis 1111 may be a center position B of the spatial coordinate measuringapparatus 1.

As shown in fig. 6, in the calibration method according to the present embodiment, the distance between the center position B and thereference portion 112 may be set as the reference distance L. In some examples, the reference distance L may be the distance between the center position B and the reference distance position a. In some examples, the reference distance position a may be a groove, and the reference distance L may be a distance between the center position B and a center of the groove.

In some examples, the reference distance L of the spatial coordinate measuringapparatus 1 is calibrated at the time of factory shipment, but due to the influence of factors such as vibration of the spatial coordinate measuringapparatus 1, the reference distance L may be changed to some extent and generate an error to affect the measurement error of the spatial coordinate measuringapparatus 1. Therefore, a reference distance error value (hereinafter referred to as a base distance error value) matching the reference distance L needs to be periodically calibrated. In this case, the overall measurement accuracy of the measuring instrument can be improved by calibrating the base distance error value.

In some examples, the spatial coordinate measuringapparatus 1 may be combined with different types ofauxiliary measuring devices 2, and there may be different base distance error values in combination with different types ofauxiliary measuring devices 2. In this case, in order to improve the measurement accuracy of the spatial coordinate measuringapparatus 1, a specific magnitude of the value of the base distance error needs to be calibrated.

In some examples, the base distance error value is sensitive to the measurement accuracy of the second length measurement value L2 (i.e., the longitudinal length measurement value) of the spatial coordinatemeasurement apparatus 1. In other words, the base distance error value may affect the measurement accuracy of the second measured length value L2 of the spatial coordinate measuringapparatus 1. In some examples, the larger the base distance error value, the larger the measurement error of the second measured length value L2. Therefore, before the spatial coordinate measuringapparatus 1 measures the target point, it is important to calibrate a specific magnitude of the base distance error value, and the comprehensive measurement accuracy of the spatial coordinate measuringapparatus 1 can be improved by the calibrated specific magnitude of the base distance error value.

In some examples, the difference between the first measured length value L1 and the second measured length value L2 may be a first error value, and if the first error value is greater than a second preset value, the base distance error value is calibrated based on the first error value, so as to correct the coordinate measurement system of the spatial coordinatemeasurement apparatus 1 by using the system compensation model. In this case, the base distance error value can be inversely calibrated based on the difference between the first measured length value L1 and the second measured length value L2, and thus the measurement error of the spatial coordinate measuringapparatus 1 can be compensated in real time to improve the comprehensive measurement accuracy. In some examples, the first error value may also be referred to as a longitudinal length error value.

In some examples, the second preset value may be 15 microns to 30 microns, for example the second preset value may be 15 microns, 16 microns, 17 microns, 18 microns, 19 microns, 20 microns, 21 microns, 22 microns, 23 microns, 24 microns, 25 microns, 26 microns, 27 microns, 28 microns, 29 microns, 30 microns, or the like. If the first error value is not greater than the second preset value, it indicates that the measurement accuracy of the spatial coordinatemeasurement instrument 1 is within the allowable error range, and at this time, the base distance error value may not be calibrated to perform real-time compensation on the spatial coordinatemeasurement instrument 1.

In some examples, if the first error value is greater than the second preset value, it indicates that the measurement accuracy of the spatial coordinate measuringapparatus 1 exceeds the allowable error range, and at this time, the base distance error value may be calibrated to compensate the spatial coordinate measuringapparatus 1 in real time. This can improve the overall measurement accuracy of the spatial coordinate measuringapparatus 1.

In some examples, the first error value may be linearly related to the base distance error value. In some examples, the first error value may be the base distance error value multiplied by a first preset multiple, and the first preset multiple may be related to the first rotation angle θ of the spatial coordinate measuringinstrument 1 in the vertical direction when the second measured length value L2 is measured. In some examples, the first rotation angle θ may be an angle by which thesecond rotation shaft 121 rotates in a process from thefirst end 31 to thesecond end 32 when the spatial coordinate measuringinstrument 1 measures the first coordinate value and the second coordinate value. In some examples, the first rotation angle θ may be an angle by which thesecond rotation axis 121 rotates during the process from thefirst end 31 to themidpoint position 33 of thereference lever 3 when the spatial coordinate measuringinstrument 1 measures the first and second coordinate values.

In some examples, the first preset multiple may be related to a trigonometric function of the first rotation angle θ, for example, the first preset multiple may include sin θ, cos θ, or the like. In some examples, the first preset multiple may further include a preset constant, for example, the preset constant may be-3, -2, -1, 0, 1, 2, or 3, etc. As described above, the first preset multiple may include-3 sin θ, -2sin θ, -sin θ, 2sin θ, 3sin θ, -3cos θ, -2cos θ, -cos θ, 2cos θ, 3cos θ, -3 θ, -2 θ, - θ, 2 θ, or 3 θ, etc. In some examples, the first preset multiple may be selected according to a method of measurement. As shown in fig. 4B, in some examples, the first rotation angle θ may be a half angle by which the spatial coordinate measuringapparatus 1 rotates during measurement. In some examples, the first rotation angle θ may be a complete angle by which the spatial coordinate measuringapparatus 1 rotates during the measurement.

As described above, in some examples, the parameter K1 may be expressed as a first preset multiple, the parameter f may be expressed as a base distance error value, and the parameter Δ L1 may be expressed as a first error value, and the relationship between the first error value and the base distance error value may be expressed by the mathematical formula (1):

ΔL1＝K1×f (1)

where Δ L1 is a first error value, K1 is a first predetermined multiple, and f is a base distance error value.

Ideally, the center position B of the spatial coordinate measuringapparatus 1 is an intersection of thefirst axis 1111 and thesecond axis 1211, but some errors may be introduced during the process of assembling, so that thefirst axis 1111 and thesecond axis 1211 have a certain amount of misalignment. As described above, in practice, the intersection of the virtual plane Z passing through thesecond axis 1211 and parallel to the bearing surface and thefirst axis 1111 may be set as the center position B of the spatial coordinate measuringapparatus 1.

As described above, in some examples, there is a certain amount of misalignment between thefirst axis 1111 and thesecond axis 1211. In other words, thefirst axis 1111 and thesecond axis 1211 do not intersect as in an ideal case, but have a certain line pitch δ. In some examples, the line spacing δ of thefirst rotation axis 111 and thesecond rotation axis 121 may be made the out-of-plane error value.

In some examples, the base distance error value and the out-of-plane error value are sensitive to the measurement accuracy of the third length measurement value L3 (i.e., the lateral length measurement value) of the spatial coordinatemeasurement apparatus 1, and may collectively affect the measurement accuracy of the third length measurement value L3. In some examples, the greater the sum of the base distance error value and the out-of-plane error value, the greater the measurement error of the third measured length value L3. Therefore, before the spatial coordinate measuringapparatus 1 measures the target point, it is significant to calibrate a specific magnitude of the out-of-plane error value, and the comprehensive measurement accuracy of the spatial coordinate measuringapparatus 1 can be improved by the calibrated out-of-plane error value.

In the calibration method according to the present embodiment, the non-coplanar error value can be calibrated based on the first measured length value L1, the third measured length value L3, and the base distance error value, and the measurement error of the spatial coordinate measuringapparatus 1 can be compensated in real time to improve the overall measurement accuracy. How to obtain the out-of-plane error value will be described in detail below.

In some examples, the difference between the first measured length value L1 and the third measured length value L3 may be made a second error value. As described above, the base distance error value and the out-of-plane error value may affect the measurement accuracy of the third measurement length value L3 of the spatial coordinate measuringapparatus 1, and if the first error value is greater than the second preset value or the second error value is greater than the third preset value, the out-of-plane error value needs to be calibrated. Under the condition, whether the space coordinate measuringinstrument 1 meets the measuring precision requirement is judged by setting a certain error range, and if not, the out-of-plane error value can be calibrated in time so as to improve the measuring precision of the measuring instrument.

In some examples, the third preset value may be 15 microns to 30 microns, for example the third preset value may be 15 microns, 16 microns, 17 microns, 18 microns, 19 microns, 20 microns, 21 microns, 22 microns, 23 microns, 24 microns, 25 microns, 26 microns, 27 microns, 28 microns, 29 microns, 30 microns, or the like. If the first error value is not greater than the second preset value or the second error value is not greater than the third preset value, it indicates that the measurement accuracy of the spatial coordinate measuringinstrument 1 is within the allowable error range, and at this time, the base distance error value may not be calibrated to perform real-time compensation on the spatial coordinate measuringinstrument 1.

In some examples, if the first error value is greater than the second preset value or the second error value is greater than the third preset value, it indicates that the measurement accuracy of the spatial coordinate measuringapparatus 1 exceeds the allowable error range, and at this time, the out-of-plane error value may be calibrated to perform real-time compensation on the spatial coordinate measuringapparatus 1. This can improve the overall measurement accuracy of the spatial coordinate measuringapparatus 1.

In some examples, the second error value may be linearly related to the base distance error value. In some examples, the second error value may be linearly related to the out-of-plane error value. In some examples, the second error value may be linearly related to a sum of the base distance error value and the out-of-plane error value.

In some examples, the second error value may be the base distance error value multiplied by a second preset multiple. In some examples, the second error value may be the out-of-plane error value multiplied by a second preset multiple. In some examples, the second error value may be a sum of the base distance error value and the out-of-plane error value multiplied by a second preset multiple.

In some examples, the second preset multiple may be related to a second rotation angle Φ of the spatial coordinate measuringinstrument 1 in the horizontal direction when the third measured length value L3 is measured. In some examples, the second preset multiple may be related to a trigonometric function of the second rotation angle Φ. For example, the second preset multiple may include sin Φ or Φ. In some examples, the second preset multiple may further include a preset constant, for example the preset constant may be-3, -2, -1, 0, 1, 2, or 3, etc. As described above, the second preset multiple may include-3 sin Φ, -2sin Φ, -sin Φ, 2sin Φ, 3sin Φ, -3 Φ, -2 Φ, - Φ, 2 Φ, or 3 Φ, etc. In some examples, the second preset multiple may be selected according to a method of measurement. As shown in fig. 5B, in some examples, the second rotation angle Φ may be a half angle by which the spatial coordinate measuringapparatus 1 rotates during measurement. In some examples, the second rotation angle Φ may be a complete angle by which the spatial coordinate measuringapparatus 1 rotates during the measurement. In some examples, the second rotation angle Φ may be the same as the first rotation angle θ.

As described above, in some examples, the parameter K2 may be expressed as a second preset multiple, the parameter f may be expressed as a base deviation value, the parameter g may be expressed as an out-of-plane deviation value, and the parameter Δ L2 may be expressed as a second deviation value, and then the relationship between the second deviation value, the base deviation value, and the out-of-plane deviation value may be expressed by the mathematical formula (2):

ΔL2＝K2×(f+g) (2)

wherein Δ L2 is a second error value, K2 is a second predetermined multiple, f is a base distance error value, and g is an out-of-plane error value.

In some examples, a sum of the base distance error value and the out-of-plane error value may be obtained based on the second error value, while the base distance error value may be obtained based on the first error value as described above. In this case, a specific magnitude of the out-of-plane error value can be obtained by calculation.

FIG. 8 is a flow chart illustrating a calibration method according to an example of the present invention. Hereinafter, the calibration method of the spatial coordinate measuringapparatus 1 will be described in detail with reference to fig. 8.

In some examples, a calibration method according to examples of the present invention may include the steps of: the first length measurement value L1 is obtained (step S100), the spatial coordinate measuringinstrument 1 is placed (step S200), the second length measurement value L2 is obtained (step S300), the third length measurement value L3 is obtained (step S400), the base distance error value is obtained (step S500), and the out-of-plane error value is obtained (step S600).

In some examples, in step S100, the actual length of thestandard bar 3, i.e., the first measured length value L1, may be measured by a dual-frequency interferometer or a three-coordinate measuring instrument.

In some examples, in step S200, the spatial coordinate measuringapparatus 1 may be placed on the supporting device 4 on the bearing surface, and thefirst rotation axis 111 of the spatial coordinate measuringapparatus 1 may be perpendicular to the bearing surface.

In some examples, in step S300, thestandard bar 3 may be fixed in front of the spatial coordinate measuringinstrument 1 by a fixing device in a manner perpendicular to the bearing surface, and a line connecting the center position B of the spatial coordinate measuringinstrument 1 and themidpoint position 33 of thestandard bar 3 may be perpendicular to thestandard bar 3; then, theauxiliary measuring device 2 is disposed on thefirst end portion 31, and the spatial coordinate measuringinstrument 1 obtains the coordinate value (i.e., the first coordinate value) of thefirst end portion 31 based on theauxiliary measuring device 2; theauxiliary measuring device 2 is moved to be disposed on thesecond end portion 32, and the spatial coordinate measuringinstrument 1 obtains the coordinate value (i.e., the second coordinate value) of thesecond end portion 32 based on theauxiliary measuring device 2. A second length measurement value L2 (i.e., a longitudinal length measurement value) of the spatial coordinate measuringinstrument 1 is obtained based on the first coordinate value and the second coordinate value.

In some examples, in step S400, thestandard bar 3 may be fixed in front of the spatial coordinate measuringinstrument 1 by a fixing device in a manner parallel to the bearing surface, the center position B of the spatial coordinate measuringinstrument 1 may be equal in height to thestandard bar 3 and a line connecting themidpoint position 33 of thestandard bar 3 may be perpendicular to thestandard bar 3; then, theauxiliary measuring device 2 is disposed on thefirst end portion 31, and the spatial coordinate measuringinstrument 1 obtains the coordinate value (i.e., the third coordinate value) of thefirst end portion 31 based on theauxiliary measuring device 2; theauxiliary measuring device 2 is moved to be disposed on thesecond end portion 32, and the spatial coordinate measuringinstrument 1 obtains the coordinate value (i.e., the fourth coordinate value) of thesecond end portion 32 based on theauxiliary measuring device 2. A third length measurement value L3 (i.e., lateral length measurement value) of the spatial coordinate measuringinstrument 1 is obtained based on the third coordinate value and the fourth coordinate value.

In some examples, in step S500, an intersection of a virtual plane Z passing through thesecond axis 1211 and parallel to the bearing surface and thefirst axis 1111 may be made a center position B of the spatial coordinate measuringapparatus 1, and a distance between the center position B and the reference distance position a may be made a reference distance L. In some examples, a first error value may be obtained based on the first measured length value L1 obtained in step S100 and the second measured length value L2 obtained in step S300, and then a base distance error value may be obtained based on the mathematical formula (1).

In some examples, in step S600, the line pitch δ of thefirst axis 1111 and thesecond axis 1211 may be made an out-of-plane error value. In some examples, the second error value may be obtained based on the first measured length value L1 obtained in step S100 and the third measured length value L3 obtained in step S400. In some examples, the sum of the base distance error value and the out-of-plane error value may be obtained based on the mathematical formula (2), and then the out-of-plane error value may be obtained based on the base distance error value obtained in step S500.

According to the invention, a base distance error value can be calibrated based on the first measured length value L1 and the second measured length value L2, the sum of the base distance error value and the out-of-plane error value can be calibrated based on the first measured length value L1 and the third measured length value L3, and then the out-of-plane error value can be obtained, and the coordinate measuring system of the space coordinate measuringinstrument 1 is corrected through the system compensation model to improve the comprehensive measuring precision of the space coordinate measuringinstrument 1.

While the invention has been described in detail in connection with the drawings and examples, it is to be understood that the above description is not intended to limit the invention in any way. Those skilled in the art can make modifications and variations to the present invention as needed without departing from the true spirit and scope of the invention, and such modifications and variations are within the scope of the invention.

Claims

1. A spatial coordinate measuring apparatus including a first rotating device having a first rotating axis and a reference portion and a second rotating device provided to the first rotating device and having a second rotating axis, the first rotating axis being orthogonal to the second rotating axis, the spatial coordinate measuring apparatus being configured to measure spatial coordinates of an auxiliary measuring device and calibrate an error of the spatial coordinate measuring apparatus using the auxiliary measuring device, the method of calibrating comprising: measuring the actual length of the standard rod as a first length measurement value; the space coordinate measuring instrument is arranged on a supporting device of a bearing surface; fixing the standard rod in a mode of being perpendicular to the bearing surface, and measuring the length of the standard rod through the space coordinate measuring instrument to obtain a second length measurement value; fixing the standard rod in a mode of being parallel to the bearing surface, and measuring the length of the standard rod through the space coordinate measuring instrument to obtain a third length measurement value; setting the intersection point of the virtual surface passing through the axis of the second rotating shaft and parallel to the bearing surface and the axis of the first rotating shaft as the central position of the space coordinate measuring instrument, setting the distance between the central position and the groove-shaped center of the reference surface of the reference part as a reference distance, and calibrating a reference distance error value matched with the reference distance based on the first length measurement value and the second length measurement value; and the line spacing between the axis of the first rotating shaft and the axis of the second rotating shaft is made to be an out-of-plane error value, and the out-of-plane error value is calibrated based on the first length measurement value, the third length measurement value and the reference distance error value.

2. The spatial coordinate measuring instrument according to claim 1, wherein:

calibrating a reference distance error value matched with the reference distance based on the first length measurement value, the second length measurement value and a first preset multiple, and calibrating the out-of-plane error value based on the first length measurement value, the third length measurement value, the reference distance error value and a second preset multiple, wherein the first preset multiple is related to a first rotation angle of the space coordinate measuring instrument in the vertical direction when the second length measurement value is measured, and the second preset multiple is related to a second rotation angle of the space coordinate measuring instrument in the horizontal direction when the third length measurement value is measured.

3. The spatial coordinate measuring instrument according to claim 1, wherein:

and the flatness deviation of the bearing surface is smaller than a first preset value.

4. The spatial coordinate measuring instrument according to claim 1, wherein:

the first rotating shaft is perpendicular to the bearing surface.

5. The spatial coordinate measuring instrument according to claim 1, wherein:

the normalization rod comprises a first end and a second end,

when the standard bar is fixed in a manner of being perpendicular to the bearing surface, the auxiliary measuring device is sequentially arranged at the first end part and the second end part to measure the coordinate value of the first end part and the coordinate value of the second end part so as to obtain the second length measurement value,

when the standard bar is fixed in a manner of being parallel to the bearing surface, the auxiliary measuring device is sequentially arranged on the first end portion and the second end portion to measure the coordinate value of the first end portion and the coordinate value of the second end portion so as to obtain the third length measurement value.

6. The spatial coordinate measuring instrument according to claim 5, wherein:

the first end and the second end are equidistant from the central location.

7. The spatial coordinate measuring instrument according to claim 2, wherein:

and if the first error value is greater than a second preset value, obtaining a product of the reference distance error value and a first preset multiple based on the first error value, and further calibrating the reference distance error value.

8. The spatial coordinate measuring instrument according to claim 7, wherein:

and if the first error value is greater than the second preset value or the second error value is greater than a third preset value, obtaining a product of the sum of the reference distance error value and the different-surface error value and a second preset multiple based on the second error value, and calibrating the different-surface error value based on the reference distance error value.

9. The spatial coordinate measuring instrument according to claim 1, wherein:

the reference part is an initial placement point of the auxiliary measuring device, and the auxiliary measuring device is placed on the reference part to initialize the space coordinate measuring device before the space coordinate measuring device measures the length of the standard rod.

10. The spatial coordinate measuring instrument according to claim 1, wherein:

the standard rod is a standard indium tile ruler, a standard carbon fiber or a guide rail containing a laser interferometer, and the first length measurement value is measured through a double-frequency interferometer or a three-coordinate measuring instrument.