A method for synchronous measurement of multi-axis form and position errors

Abstract

This invention discloses a method for synchronous measurement of multi-axis form and position errors. The specific method is as follows: Step 1: The laser module outputs an initial laser beam, which is then split into a first Y-axis collimated beam, a second Y-axis collimated beam, and a Z-axis collimated beam by a beam-splitting and steering system. Step 2: The sliders on the first, second, and third linear guides are moved synchronously, and the coordinate values ​​of the laser points at different positions of each slider are recorded using a two-dimensional position detector. Step 3: Based on the data obtained in Step 2, the trajectory equations of the slider movements on the first, second, and third linear guides are fitted. Step 4: The parallelism between the first and second linear guides and the perpendicularity between the first and third linear guides are calculated. This invention can simultaneously measure multiple form and position errors, such as parallelism and perpendicularity, between guides in a single measurement, eliminating the need for individual measurements and significantly improving measurement efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of measurement, in particular to a multi-axis form error synchronous measurement method. BACKGROUND

[0002] Under actual production and operation conditions, the multi-axis cooperative system of the linear guide rail is extremely susceptible to multiple factors to generate form errors. From the external environment, temperature fluctuations in the industrial workshop can cause the guide rail base material to expand and contract with heat, changing the geometric size and installation accuracy of the guide rail; air disturbance can interfere with the optical measurement signal, indirectly affecting the detection accuracy of the guide rail movement precision. From the internal factors, mechanical wear after long-term operation of the guide rail, accumulation of small stresses generated during the assembly process, and synchronization deviation of each axis movement during multi-axis linkage, all of which can cause the generation of core form errors such as parallelism and perpendicularity.

[0003] Form errors restrict the improvement of guide rail precision, which can reduce the machining efficiency and product qualification rate of high-end equipment. Therefore, it is necessary to develop a linear guide rail multi-axis system for high-end equipment with high-precision detection and dynamic compensation capability.

[0004] From the perspective of measurement logic and precision, traditional form measurement technology relies on the detection means of traditional measuring tools such as dial gauges and straight edges, which requires frequent switching of measurement references during operation, is cumbersome to operate, and is difficult to build a comprehensive and accurate multi-axis correlation error model, thus unable to effectively capture the complex coupling errors during multi-axis linkage. At the same time, there is an unavoidable human error in the manual reading process, which further amplifies the measurement error.

[0005] In terms of measurement efficiency and scene adaptability, the measurement method using a laser interferometer has certain advantages in terms of precision, but the measurement process requires the construction of a complex optical system, the equipment cost is high, and the operation precision requirement is extremely high. When facing the complex spatial layout of the internal structure of the industrial mother machine, as well as the special working conditions of the large-span beam and high column of large gantry equipment in aerospace, the light path is easily blocked, resulting in the need for multiple tedious light path adjustments, and the entire measurement period is often several hours, which greatly affects the production efficiency, and it is difficult to meet the rapid and efficient measurement requirements in actual engineering. SUMMARY

[0006] The purpose of the present application is to solve the deficiencies in the prior art, and to provide a multi-axis form error synchronous measurement method.

[0007] The purpose of the present application is achieved by the technical scheme that a multi-axis form error synchronous measurement method, a measurement system comprising a laser module, a light splitting and turning system, a two-dimensional position detector A arranged on a slider of a first linear guide rail, a two-dimensional position detector B arranged on a slider of a second linear guide rail, and a two-dimensional position detector C arranged on a slider of a third linear guide rail.

[0008] The specific measurement method is as follows:

[0009] Step one: the laser module outputs initial laser, which is split into a first Y-axis collimated light beam, a second Y-axis collimated light beam and a Z-axis collimated light beam by the light splitting and turning system; the first Y-axis collimated light beam, the second Y-axis collimated light beam and the Z-axis collimated light beam are respectively injected into the two-dimensional position detector A, the two-dimensional position detector B and the two-dimensional position detector C;

[0010] Step two: synchronously move the sliders on the first linear guide rail, the second linear guide rail and the third linear guide rail, and record the laser point coordinate values of each slider at different positions by the two-dimensional position detector to form coordinate point cloud data;

[0011] Step three: based on the data obtained in step two, fit the moving track equations of the sliders on the first linear guide rail, the second linear guide rail and the third linear guide rail;

[0012] Step four: calculate the direction vectors of the first linear guide rail, the second linear guide rail and the third linear guide rail according to the moving track equations; the direction vector of the first linear guide rail is perpendicular to the XoZ plane, the direction vector of the second linear guide rail is perpendicular to the XoZ plane, and the direction vector of the third linear guide rail is perpendicular to the XoY plane; and calculate the parallelism between the first linear guide rail and the second linear guide rail and the perpendicularity between the first linear guide rail and the third linear guide rail.

[0013] As a preferred, the light splitting and turning system comprises a beam splitter A corresponding to the first linear guide rail, a beam splitter B corresponding to the third linear guide rail, a mirror A corresponding to the third linear guide rail, and a mirror B corresponding to the second linear guide rail; the initial laser first passes through the beam splitter A to form a first Y-axis collimated light beam and a first X-axis collimated light beam, and the first Y-axis collimated light beam is injected into the two-dimensional position detector A; the first X-axis collimated light beam passes through the beam splitter to form a second X-axis collimated light beam and a third Y-axis collimated light beam, and the third Y-axis collimated light beam passes through the mirror A to obtain a Z-axis collimated light beam and is injected into the two-dimensional position detector C; the second X-axis collimated light beam passes through the mirror B to form a second Y-axis collimated light beam and is injected into the two-dimensional position detector B.

[0014] As a preferred, the first linear guide rail, the second linear guide rail and the third linear guide rail are all arranged on a marble platform.

[0015] Preferably, in step one, a temporary spot observation screen is placed in the optical path of the first Y-axis collimated beam, the second Y-axis collimated beam, and the Z-axis collimated beam to ensure that the shape of the laser spot projected on the temporary spot observation screen meets the set requirements; and by adjusting the angles of each beam splitter and reflector, the first Y-axis collimated beam, the second Y-axis collimated beam, and the Z-axis collimated beam are respectively incident into the center of the measurement surface of the corresponding two-dimensional position detector.

[0016] Preferably, the laser module uses a tunable power semiconductor laser with an output laser wavelength of 635nm-655nm and a power range of 1mW-50mW; both beam splitter A and beam splitter B are non-polarized cubic beam splitters.

[0017] Preferably, in step two, after obtaining the laser point coordinate data at different positions of each slider, the obtained data is preprocessed and abnormal laser point coordinate data is removed.

[0018] As a preferred method, the following approach is used to remove abnormal laser point coordinate data:

[0019] First, calculate the mean X-coordinate of the coordinate point cloud data. and the mean of the Y coordinate Then based on the average of the X coordinates and the mean of the Y coordinate Calculate the two-dimensional deviation of the coordinate values ​​of each laser point. ;

[0020] ;

[0021] Next, calculate the mean of the two-dimensional deviation. ;

[0022] Based on the two-dimensional deviation of the coordinate values ​​of each laser point and the mean of two-dimensional deviation Calculate the root mean square error (RMSE).

[0023] ;

[0024] If the current two-dimensional deviation of the laser point coordinates In the interval If the coordinates of the laser point are within the acceptable range, they will be retained; otherwise, the coordinates of the laser point will be considered abnormal and will be discarded.

[0025] As a preferred option, the specific method for step three is as follows:

[0026] S1: Fit the coordinate point cloud data using ordinary least squares to obtain an initial fitted line, and use the parameters of this initial fitted line as the initial iteration values ​​to calculate the residual from each laser point to the initial line. ;

[0027] S2: Calculate the residuals the median of ;

[0028] S3: Calculate the absolute deviation of the residuals from the median. And calculate the absolute deviation. the median of Then calculate the scale parameters. Scale parameters The median of the absolute deviation The product of the fixed coefficient f;

[0029] S4: Based on the Huber weighting function and combined with the residual Scale parameters Calculate the weight of each laser point coordinate value ;

[0030] S5: Weight-based Recalculate the parameters of the fitted line and update the residuals. Repeat steps S2 to S5 until the set number of iterations is reached, thereby fitting the final equation of the slider's movement trajectory.

[0031] Preferably, a data processing module and a storage module are also included. After step four is completed, the data processing module outputs a report containing laser module parameters, raw data collected by the two-dimensional position detector, parallelism data, and perpendicularity data. At the same time, the raw data and processing results are stored in the storage module for subsequent quality analysis and traceability.

[0032] The beneficial effects of this invention are:

[0033] 1. Traditional methods rely on axis-by-axis measurement and manual reference switching, making it difficult to capture the complex coupling errors in multi-axis linkage. This invention uses three two-dimensional position detectors to simultaneously collect data and combines trajectory equation fitting and direction vector calculation to directly quantify the spatial correlation of the motion trajectories of each axis. For example, by calculating the parallelism deviation between the first and second guide rails, the superimposed error caused by the non-parallelism of the guide rails during two-axis linkage can be accurately identified. This measurement advantage is particularly crucial in multi-axis linkage scenarios such as high-end machine tool processing of impellers and aerospace structural components.

[0034] 2. The position resolution of the two-dimensional position detector of the present invention can reach the level of 1 micrometer. Compared with the manual reading error of traditional dial gauges (±0.01mm level), the present invention eliminates the friction error introduced by mechanical contact and human observation bias through non-contact measurement of laser collimated beam and detector, and has the advantage of high measurement accuracy. At the same time, the trajectory equation fitting adopts mathematical tools such as least squares method to extract the essential trend of guide rail motion, further improving the measurement reliability.

[0035] 3. In view of the problems of high cost of traditional laser interferometers and complicated equipment layout caused by the need for additional optical path components for multi-axis measurement, the measurement system of the present invention has greatly reduced equipment cost, and the optical path layout is relatively simple and easy to operate. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the measurement system of the present invention.

[0037] In the diagram: 1. Laser module, 2. Beam splitter A, 3. Beam splitter B, 4. Reflector B, 5. Two-dimensional position detector B, 6. Reflector A, 7. Two-dimensional position detector C, 8. Two-dimensional position detector A, 9. Second linear guide rail, 10. Third linear guide rail, 12. First linear guide rail, 15. Marble platform. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0039] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0040] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0041] like Figure 1 As shown, a method for synchronous measurement of multi-axis form and position errors is provided. The measurement system includes a laser module 1, a beam-splitting and steering system, a two-dimensional position detector A8 mounted on the slider of the first linear guide rail 12, a two-dimensional position detector B5 mounted on the slider of the second linear guide rail 9, and a two-dimensional position detector C7 mounted on the slider of the third linear guide rail 10.

[0042] The measurement method of the present invention is as follows:

[0043] Step 1: Laser module 1 outputs an initial laser beam, which is then split into a first Y-axis collimated beam, a second Y-axis collimated beam, and a Z-axis collimated beam by a beam-splitting and steering system. These beams are then directed into two-dimensional position detectors A8, B5, and C7, respectively. Specifically, the first Y-axis collimated beam is parallel to the first linear guide rail 12, the second Y-axis collimated beam is parallel to the second linear guide rail 9, and the Z-axis collimated beam is parallel to the third linear guide rail 10.

[0044] Step 2: Simultaneously move the sliders on the first linear guide rail 12, the second linear guide rail 9, and the third linear guide rail 10, and use a two-dimensional position detector to record the laser point coordinate values ​​of each slider at different positions to form coordinate point cloud data.

[0045] Step 3: Based on the data obtained in Step 2, fit the equations of the slider movement trajectory on the first linear guide rail, the second linear guide rail, and the third linear guide rail.

[0046] Step 4: Calculate the direction vectors of the first linear guide rail 12, the second linear guide rail 9, and the third linear guide rail 10 respectively based on the trajectory equation; see appendix. Figure 1 In the coordinate system, the direction vector of the first linear guide is perpendicular to the XoZ plane, the direction vector of the second linear guide is perpendicular to the XoZ plane, and the direction vector of the third linear guide is perpendicular to the XoY plane; and calculate the parallelism between the first and second linear guides and the perpendicularity between the first and third linear guides.

[0047] Traditional methods rely on axis-by-axis measurement and manual reference switching, making it difficult to capture the complex coupling errors in multi-axis linkage. This invention uses three two-dimensional position detectors to simultaneously collect data and combines trajectory equation fitting and direction vector calculation to directly quantify the spatial correlation of the motion trajectories of each axis. For example, by calculating the parallelism deviation between the first and second guide rails, the superimposed error caused by guide rail non-parallelism during two-axis linkage can be accurately identified. This measurement advantage is particularly crucial in multi-axis linkage scenarios such as high-end machine tool processing of impellers and aerospace structural components.

[0048] The position resolution of the two-dimensional position detector of this invention can reach the level of 1 micrometer. Compared with the manual reading error of traditional dial gauges (±0.01mm level), this invention eliminates friction error introduced by mechanical contact and human observation bias through non-contact measurement of laser collimated beam and detector, and has the advantage of high measurement accuracy. At the same time, the trajectory equation fitting adopts mathematical tools such as least squares method to extract the essential trend of guide rail motion, further improving the measurement reliability.

[0049] To address the issues of high cost per unit for traditional laser interferometers and cumbersome equipment layout due to the need for additional optical path components for multi-axis measurements, the measurement system of this invention significantly reduces equipment cost, simplifies optical path layout, and makes operation more convenient.

[0050] This invention can simultaneously measure multiple form and position errors such as parallelism and perpendicularity between guide rails in a single measurement, eliminating the need for individual measurements and greatly improving measurement efficiency, thus meeting the needs of fast and efficient measurement in practical engineering.

[0051] The beam-splitting and steering system includes a beam-splitting mirror A2 corresponding to the first linear guide rail 12, a beam-splitting mirror B3 corresponding to the third linear guide rail 10, a reflecting mirror A6 corresponding to the third linear guide rail, and a reflecting mirror B4 corresponding to the second linear guide rail 9. The initial laser beam first passes through beam-splitting mirror A2 to form a first Y-axis collimated beam and a first X-axis collimated beam. The first Y-axis collimated beam enters the two-dimensional position detector A8. After passing through the beam-splitting mirror, the first X-axis collimated beam forms a second X-axis collimated beam and a third Y-axis collimated beam. The third Y-axis collimated beam passes through reflecting mirror A6 to obtain a Z-axis collimated beam and enters the two-dimensional position detector C7. The second X-axis collimated beam passes through reflecting mirror B4 to form a second Y-axis collimated beam and enters the two-dimensional position detector B5. The first Y-axis collimated beam is parallel to the first linear guide rail, the second Y-axis collimated beam is parallel to the second linear guide rail, and the Z-axis collimated beam is parallel to the third linear guide rail.

[0052] During measurement, the first linear guide rail 12, the second linear guide rail 9, and the third linear guide rail 10 are all mounted on the marble platform 15. The marble platform 15 possesses extremely high precision and stability, with minimal geometric tolerances such as flatness and straightness. Mounting the linear guide rails on the marble platform leverages its high precision to achieve micron-level flatness on the mounting surface and one-micron-level linearity, thus providing a high-precision mounting reference for the linear guide rails. This ensures the movement accuracy of the slider on the guide rails, thereby improving the overall measurement accuracy of the measurement system. Furthermore, marble exhibits excellent thermal and mechanical stability, with a low coefficient of linear expansion, maintaining stable performance under various environmental conditions and resisting deformation due to temperature changes, mechanical vibrations, and other factors. Mounting the linear guide rails on the marble platform allows the measurement system to maintain stable operation in various environments, reducing the impact of external factors on the guide rail movement and measurement results, and ensuring the reliability and repeatability of the measurement data.

[0053] In this embodiment, laser module 1 uses a tunable power semiconductor laser with an output laser wavelength of 635nm-655nm and a power range of 1mW-50mW; beam splitters A2 and B3 are both non-polarized cubic beam splitters. The beam splitting ratio of beam splitter A is 70:30, and the beam splitting ratio of beam splitter B is 50:50.

[0054] In step one, a temporary spot observation screen is placed in the optical paths of the first Y-axis collimated beam, the second Y-axis collimated beam, and the Z-axis collimated beam to ensure that the shape of the laser spot projected on the temporary spot observation screen meets the set requirements; and by adjusting the angles of each beam splitter and reflector, the first Y-axis collimated beam, the second Y-axis collimated beam, and the Z-axis collimated beam are respectively incident into the center of the measurement surface of the corresponding two-dimensional position detector.

[0055] The light spot projected onto the temporary observation screen must be circular with an ellipticity ≤1.1 and a light intensity distribution uniformity ≥90%. If the light spot shape does not meet the requirements, the laser module and optical path need to be adjusted to achieve the desired shape. This operation prevents the impact of "unqualified light spots" on subsequent measurements from the outset. If the light spot shape is abnormal, the coordinates of the laser point recorded by the two-dimensional position detector will show systematic deviations (such as inaccurate center positioning of the light spot), leading to distortions in trajectory fitting and shape and position error calculations. Therefore, pre-calibration of the light spot shape is fundamental to ensuring accurate measurement results.

[0056] In step two, the coordinates of the laser point detected by the two-dimensional position detector are... The coordinates of this laser point The planar coordinates corresponding to the measurement surface of the two-dimensional detector Let X be the X coordinate value of the i-th laser point. Let be the Y-coordinate value of the i-th laser point. j For the corresponding linear guide rail.

[0057] After obtaining the laser point coordinate data at different positions of each slider, the obtained data is preprocessed and abnormal laser point coordinate data is removed.

[0058] The method for removing abnormal laser point coordinate data is as follows:

[0059] First, calculate the mean X-coordinate of the coordinate point cloud data. and the mean of the Y coordinate ,

[0060] Mean of X-coordinate The calculation formula is as follows:

[0061] ;

[0062] Mean of Y-coordinate The calculation formula is as follows:

[0063] ;

[0064] Where n is the number of laser points.

[0065] Then based on the mean of the X-coordinate and the mean of the Y coordinate Calculate the two-dimensional deviation of the coordinate values ​​of each laser point. ;

[0066] ;

[0067] Next, calculate the mean of the two-dimensional deviation. ;

[0068] Two-dimensional deviation mean The calculation formula is as follows:

[0069] ;

[0070] Based on the two-dimensional deviation of the coordinate values ​​of each laser point and the mean of two-dimensional deviation Calculate the root mean square error (RMSE).

[0071] ;

[0072] If the current two-dimensional deviation of the laser point coordinates In the interval If the coordinates of the laser point are within the acceptable range, they will be retained; otherwise, the coordinates of the laser point will be considered abnormal and will be discarded.

[0073] By removing substandard raw data, anomalies are eliminated while maintaining a data retention rate of over 95%, balancing data purification and data integrity, thus laying the foundation for subsequent accurate measurement and analysis.

[0074] Furthermore, the specific method for step three is as follows:

[0075] S1: Fit the coordinate point cloud data using ordinary least squares to obtain an initial fitted line, and use the parameters of this initial fitted line as the initial iteration values ​​to calculate the residual from each laser point to the initial line. ;

[0076] Let the equation of the initial fitted line be:

[0077] (1);

[0078] laser point coordinates Substituting into the above formula, the sum of squares of the residuals Calculated using the following formula:

[0079] (2);

[0080] when When it is at its minimum, for equation (2) with respect to and Taking the partial derivative and setting it to 0, we finally obtain:

[0081] ;

[0082] ;

[0083] in:

[0084] ; for The average value of the x-coordinate of a point.

[0085] ; for The average value of the y-coordinate of a point.

[0086] ; It is the sum of squares of the deviations of x from the mean (i.e., the sum of the squares of the differences between the x-coordinate and its mean).

[0087] ; It is the sum of the products of the differences between the x-coordinate and the mean of the y-coordinate (i.e., the sum of the products of the differences between the x-coordinate and the y-coordinate and their respective means).

[0088] laser point to the initial line residual for:

[0089] .

[0090] S2: Calculate the residuals the median of During calculation, the residuals are sorted in ascending order to form a sequence. If n is odd, the residual value at the middle position of the sequence is taken as the median. If n is even, then the median is the average of the two middle residuals of the sequence. .

[0091] S3: Calculate the absolute deviation of the residuals from the median. And calculate the absolute deviation. the median of Then calculate the scale parameters. Scale parameters The median of the absolute deviation The product of the product with a fixed coefficient f, where the fixed coefficient f takes the value 1.4826.

[0092] S4: Based on the Huber weighting function and combined with the residual Scale parameters Calculate the weight of each laser point coordinate value ;

[0093] Huber weight function as follows:

[0094] ;

[0095] The value is 1.345. The larger the residual, the lower the weight of the coordinate point. By assigning low weights to points with large residuals through coordinates, the impact of outliers can be reduced.

[0096] S5: Weight-based Recalculate the parameters of the fitted line and update the residuals. Repeat steps S2 to S5 until the set number of iterations is reached, thereby fitting the final equation of the slider's movement trajectory.

[0097] Through the fitting calculation using the above method, the final equation for the slider movement trajectory of the first linear guide rail is: The equation for the trajectory of the slider on the second linear guide is: The equation for the trajectory of the slider on the third linear guide is: .

[0098] This invention optimizes the straight line fitting process by using the result of ordinary least squares as the initial value and combining it with a robust weighted iterative least squares method with the Huber weight function of the linear point cloud to enhance the resistance to interference data.

[0099] In step four, the form and position error is calculated by determining the direction vector of the first linear guide. The direction vector Perpendicular to the XoZ plane; direction vector of the second linear guide. The direction vector Perpendicular to the XoZ plane; direction vector of the third linear guide. The direction vector The direction vector of the third linear guide is perpendicular to the XoY plane. (Based on the fitted linear direction vector) and The parallelism between the first and second linear guides can be calculated as follows:

[0100] ;

[0101] The perpendicularity between the first linear guide 12 and the third linear guide is:

[0102] .

[0103] The present invention also includes a data processing module and a storage module; after step four is completed, the data processing module outputs a report containing laser module parameters, raw data collected by the two-dimensional position detector, parallelism data, and perpendicularity data, and stores the raw data and processing results in the storage module for subsequent quality analysis and traceability.

[0104] This invention is not limited to the preferred embodiments described above. Anyone can derive other products in various forms under the guidance of this invention. However, regardless of any changes in shape or structure, any technical solution that is the same as or similar to this application falls within the protection scope of this invention.

Claims

1. A method of simultaneous measurement of multi-axis form error, characterized in that, The measurement system comprises a laser module, a light splitting and turning system, a two-dimensional position detector A arranged on a slider of a first linear guide rail, a two-dimensional position detector B arranged on a slider of a second linear guide rail, and a two-dimensional position detector C arranged on a slider of a third linear guide rail. The specific measurement method is as follows: Step one: the laser module outputs initial laser, which is split into a first Y-axis collimated light beam, a second Y-axis collimated light beam and a Z-axis collimated light beam by the light splitting and turning system; the first Y-axis collimated light beam, the second Y-axis collimated light beam and the Z-axis collimated light beam are respectively injected into the two-dimensional position detector A, the two-dimensional position detector B and the two-dimensional position detector C; Step two: the sliders on the first linear guide rail, the second linear guide rail and the third linear guide rail are synchronously moved, and the two-dimensional position detector is used to record the laser point coordinate values of each slider at different positions to form coordinate point cloud data; Step three: based on the data obtained in step two, the moving track equations of the sliders on the first linear guide rail, the second linear guide rail and the third linear guide rail are fitted; Step four: the direction vectors of the first linear guide rail, the second linear guide rail and the third linear guide rail are respectively calculated according to the moving track equations; the direction vector of the first linear guide rail is perpendicular to the XoZ plane, the direction vector of the second linear guide rail is perpendicular to the XoZ plane, and the direction vector of the third linear guide rail is perpendicular to the XoY plane; and the parallelism between the first linear guide rail and the second linear guide rail and the perpendicularity between the first linear guide rail and the third linear guide rail are calculated.

2. The method of claim 1, wherein, The light splitting and turning system comprises a beam splitter A corresponding to the first linear guide rail, a beam splitter B corresponding to the third linear guide rail, a mirror A corresponding to the third linear guide rail, and a mirror B corresponding to the second linear guide rail; the initial laser first passes through the beam splitter A to form the first Y-axis collimated light beam and the first X-axis collimated light beam, and the first Y-axis collimated light beam is injected into the two-dimensional position detector A; the first X-axis collimated light beam passes through the beam splitter to form the second X-axis collimated light beam and the third Y-axis collimated light beam, and the third Y-axis collimated light beam passes through the mirror A to obtain the Z-axis collimated light beam and is injected into the two-dimensional position detector C; The second X-axis collimated light beam passes through the mirror B to form the second Y-axis collimated light beam and is injected into the two-dimensional position detector B.

3. The method of claim 1, wherein, The first linear guide rail, the second linear guide rail and the third linear guide rail are all arranged on a marble platform.

4. The method of claim 1, wherein, In step one, a temporary light spot observation screen is placed in the light paths of the first Y-axis collimated light beam, the second Y-axis collimated light beam and the Z-axis collimated light beam to ensure that the shape of the laser spot projected on the temporary light spot observation screen meets the set requirements; And by adjusting the angles of each beam splitter and mirror, the first Y-axis collimated light beam, the second Y-axis collimated light beam and the Z-axis collimated light beam are respectively injected into the measurement center of the corresponding two-dimensional position detector.

5. The method of claim 2, wherein, The laser module adopts an adjustable power semiconductor laser, the wavelength of the output laser is 635nm-655nm, and the power range is 1mW-50mW; the beam splitter A and the beam splitter B both adopt a non-polarized cubic beam splitter.

6. The method of claim 1, wherein, In step two, after obtaining the laser point coordinate data of different positions of each slider, the obtained data is preprocessed, and abnormal laser point coordinate data is removed.

7. The method of claim 6, wherein, The method for removing abnormal laser point coordinate data is as follows: First, calculate the mean X-coordinate of the coordinate point cloud data. and the mean of the Y coordinate Then based on the average of the X coordinates and the mean of the Y coordinate Calculate the two-dimensional deviation of the coordinate values ​​of each laser point. ; ； Next, the two-dimensional bias mean is calculated ; a two-dimensional deviation of the individual laser point coordinate values and a two-dimensional deviation mean value a root mean square difference RMSE is calculated; ； If the current two-dimensional deviation of the laser point coordinates In the interval If the coordinates of the laser point are within the acceptable range, they will be retained; otherwise, the coordinates of the laser point will be considered abnormal and will be discarded.

8. The method of claim 1, wherein, The specific method of step three is as follows: S1: fitting the coordinate point cloud data by ordinary least square method and obtaining an initial fitting straight line, and taking the parameters of the initial fitting straight line as initial iteration values to calculate the residual of each laser point to the initial straight line ; S2: compute residual median of ; S3: Calculate the median of the absolute deviations of the residuals from the median and calculate the median of the absolute deviations and then calculate the scale parameter ;​ scale parameter median of absolute deviations product with a fixed coefficient f; S4: Calculate the weight of each laser point coordinate value according to Huber weight function and combining the residual , scale parameter weight of each laser point coordinate value ; S5: Based on the weight Recalculating the parameters of the fitting straight line and updating the residual error ; repeating steps S2 to S5 until the number of iterations reaches the set number, thereby fitting the final slider movement trajectory equation.

9. The method of claim 1, wherein, The application also comprises a data processing module and a storage module; after step four is completed, the data processing module outputs a report containing the laser module parameters, the original data collected by the two-dimensional position detector, the parallelism data and the perpendicularity data, and stores the original data and the processing results to the storage module for subsequent quality analysis and traceability.

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