Multi-axis shape and position error synchronous measuring device

Abstract

The utility model provides a multi-axis shape and position error synchronous measuring device. The multi-axis shape and position error synchronous measuring device comprises a laser module, a light splitting steering system, a two-dimensional position detector A arranged on a sliding block of a first linear guide rail, a two-dimensional position detector B arranged on a sliding block of a second linear guide rail, and a two-dimensional position detector C arranged on a sliding block of a third linear guide rail, initial laser output by the laser module is divided into a first Y-axis collimated light beam, a second Y-axis collimated light beam and a third X-axis collimated light beam through the light splitting steering system, and the first Y-axis collimated light beam, the second Y-axis collimated light beam and the third X-axis collimated light beam enter the two-dimensional position detector A, the two-dimensional position detector B and the two-dimensional position detector C respectively. According to the utility model, multiple form and position errors such as parallelism and verticality between the guide rails can be measured at the same time through one-time measurement, one-by-one measurement is not needed, and the measurement efficiency is greatly improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of measurement technology, especially to a multi -axis shape error synchronous measuring device. BACKGROUND

[0002] Under actual production and operation conditions, the multi-axis collaborative system of the linear guide rail is extremely susceptible to multiple factors to produce shape 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 accuracy. From the internal factors, mechanical wear after long-term operation of the guide rail, accumulation of small stresses generated during assembly, and synchronization deviation of each axis during multi-axis linkage, all of which can cause the generation of core shape errors such as parallelism and perpendicularity.

[0003] Shape errors restrict the improvement of guide rail accuracy, 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 accuracy, traditional shape measurement technology relies on the detection means of traditional measuring tools such as dial gauges and straight edges. The operation process requires frequent switching of measurement references, which is tedious and 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. Moreover, the traditional measurement method can only measure step by step when measuring the parallelism or perpendicularity between different guide rails, and cannot be completed in the same measurement process, resulting in a long measurement time and low measurement efficiency, which cannot meet the rapid and efficient measurement requirements in actual engineering. UTILITY MODEL CONTENTS

[0005] The utility model aims at solving the problems in the prior art, and provides a multi-axis shape error synchronous measuring device.

[0006] The utility model aims at solving the problems in the prior art, and provides a multi-axis shape error synchronous measuring device.

[0007] As preferred, the first Y-axis collimated light beam is parallel to the first linear guide rail, the second Y-axis collimated light beam is parallel to the second linear guide rail, and the third X-axis collimated light beam is parallel to the third linear guide rail.

[0008] As preferred, the light splitting and turning system comprises a beam splitter A corresponding to the first linear guide rail, a mirror A and a mirror B corresponding to the third linear guide rail, a mirror C corresponding to the second linear guide rail, and a beam splitter B between the beam splitter A and the mirror C, the beam splitter B corresponding to the mirror B.

[0009] As preferred, the first linear guide rail, the second linear guide rail and the third linear guide rail are all arranged on a marble platform.

[0010] As preferred, the laser module adopts an adjustable power semiconductor laser, and the wavelength of the output laser is 635nm-655nm, and the power range is 1mW-50mW.

[0011] As preferred, the beam splitter A and the beam splitter B both adopt a non-polarized cubic beam splitter.

[0012] As preferred, the light splitting ratio of the beam splitter A is 70:30, and the light splitting ratio of the beam splitter B is 50:50.

[0013] The beneficial effects of the utility model are:

[0014] 1、 the utility model discloses a light splitting and turning system divides the initial laser output by laser module into multiple collimated light beams, and respectively enters two-dimensional position detector arranged on different linear guide rail sliders; This design can measure the shape and position error of multiple axes at the same time, can effectively capture the complex coupling error when multiple axes are linked, avoids the error caused by frequent switching of measurement reference in traditional measurement technology, also reduces the inevitable human bias in manual reading process, thereby improves the measurement precision, can satisfy the ultra-high precision measurement demand required by high-end industrial mother machine and aerospace equipment.

[0015] 2、 the utility model discloses once measurement, can simultaneously measure the parallelism, perpendicularity and multiple shape and position errors between guide rails, need not measure one by one, and the measurement efficiency is greatly improved, satisfies the quick, efficient measurement demand in actual engineering. DRAWINGS

[0016] Figure 1 It is the structural schematic diagram of the measurement system of the utility model.

[0017] In the diagram: 1. Laser module, 2. Beam splitter A, 3. Beam splitter B, 4. Reflector C, 5. Two-dimensional position detector B, 6. Reflector A, 7. Reflector B, 8. Two-dimensional position detector C, 9. Two-dimensional position detector A, 10. First linear guide rail, 11. Third linear guide rail, 12. Second linear guide rail, 13. Marble platform. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model are within the protection scope of the present utility model.

[0019] Those skilled in the art should understand that, in the disclosure of this utility model, 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 utility model 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 limitations on this utility model.

[0020] 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.

[0021] like Figure 1 As shown, a method for synchronous measurement of multi-axis form and position errors is described, which uses a multi-axis form and position error synchronous measurement device. The multi-axis form and position error synchronous measurement device includes a laser module 1, a beam-splitting and steering system, a two-dimensional position detector A9 mounted on the slider of the first linear guide rail 10, a two-dimensional position detector B5 mounted on the slider of the second linear guide rail 12, and a two-dimensional position detector C8 mounted on the slider of the third linear guide rail 11.

[0022] The measurement method is as follows:

[0023] Step one: the laser module 1 outputs initial laser, and the initial laser is divided into a first Y-axis collimated light beam, a second Y-axis collimated light beam and a third X-axis collimated light beam through a light splitting and turning system; the first Y-axis collimated light beam, the second Y-axis collimated light beam and the third X-axis collimated light beam are respectively injected into two-dimensional position detectors A9, B5 and C8. Among them, the first Y-axis collimated light beam is parallel to the first linear guide rail 10, the second Y-axis collimated light beam is parallel to the second linear guide rail 12, and the third X-axis collimated light beam is parallel to the third linear guide rail 11.

[0024] Step two: synchronously move the sliders on the first linear guide rail 10, the second linear guide rail 12 and the third linear guide rail 11, and record the laser point coordinate values of each slider at different positions by using the two-dimensional position detectors to form coordinate point cloud data.

[0025] 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.

[0026] Step four: the direction vectors of the first linear guide rail 10, the second linear guide rail 12 and the third linear guide rail 11 are calculated according to the moving track equations respectively; 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. Among them, the direction vector of the first linear guide rail 10 is perpendicular to the XoZ plane, the direction vector of the second linear guide rail 12 is perpendicular to the XoZ plane, and the direction vector of the third linear guide rail 11 is perpendicular to the YoZ plane.

[0027] The traditional method relies on axis-by-axis measurement and manual reference switching, and it is difficult to capture the complex coupling error when multiple axes are linked. The utility model can directly quantify the spatial correlation of the motion track of each axis by synchronously collecting data through three two-dimensional position detectors and combining trajectory equation fitting and direction vector calculation. For example, by calculating the parallelism deviation of the first guide rail and the second guide rail, the superimposed error caused by the non-parallelism of the guide rails when the two axes are linked can be accurately identified. This measurement advantage is particularly critical in the multi-axis linkage scene of high-end machine tool processing impellers, aerospace structural parts and the like.

[0028] The position resolution of the two-dimensional position detector of the utility model can reach 1 micrometer level. Compared with the manual reading error (±0.01mm level) of the traditional dial gauge, the utility model eliminates the friction error introduced by mechanical contact and the human observation deviation through non-contact measurement of laser collimated light beam and detector, and has the advantages of high measurement accuracy. At the same time, the least square method and other mathematical tools are used for trajectory equation fitting to extract the essential trend of guide rail movement, further improving the measurement reliability.

[0029] The device cost of the measurement system is greatly reduced, and the light path arrangement is relatively simple, and the operation is relatively simple.

[0030] The parallelism, perpendicularity and other shape and position errors between guide rails can be measured at a time, without needing to be measured one by one, the measurement efficiency is greatly improved, and the rapid and efficient measurement requirement in actual engineering is met.

[0031] The initial laser first passes through the beam splitter A2 to form a first Y-axis collimated light beam and a first X-axis collimated light beam, the first Y-axis collimated light beam is injected into the two-dimensional position detector A9; 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, the third Y-axis collimated light beam passes through the mirrors A6 and B7 to obtain a third X-axis collimated light beam and is injected into the two-dimensional position detector C8; the second X-axis collimated light beam passes through the mirror C4 to form a second Y-axis collimated light beam and is injected into the two-dimensional position detector B5. The first Y-axis collimated light beam is parallel to the first linear guide rail, the second Y-axis collimated light beam is parallel to the second linear guide rail, and the third X-axis collimated light beam is parallel to the third linear guide rail.

[0032] In the measurement, the first linear guide rail 10, the second linear guide rail 12 and the third linear guide rail 11 are all arranged on the marble platform 13. The marble platform 13 has very high precision and stability, and the flatness, straightness and other shape and position tolerances are very small. By installing the linear guide rail on the marble platform, the high precision of the marble platform can be used to make the installation surface flatness of the linear guide rail reach microns, and the linear straightness can reach one micron, thereby providing a high-precision installation reference for the linear guide rail, ensuring the movement precision of the slider on the linear guide rail, and further improving the measurement precision of the entire measurement system. Secondly, the marble has excellent thermal stability and mechanical stability, and has a low linear expansion coefficient, and can maintain stable performance under different environmental conditions and is not easy to deform due to temperature changes, mechanical vibrations and other factors. By arranging the linear guide rail on the marble platform, the measurement system can maintain a stable working state under various environments, reduce the influence of external factors on the movement of the linear guide rail and the measurement result, and ensure the reliability and repeatability of the measurement data.

[0033] In this embodiment, the laser module 1 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 A2 and the beam splitter B3 both adopt a non-polarized cubic beam splitter. The light splitting ratio of the beam splitter A is 70:30, and the light splitting ratio of the beam splitter B is 50:50.

[0034] In step one, a temporary light spot observation screen is placed in the light path of the first Y-axis collimated light beam, the second Y-axis collimated light beam and the third X-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 third X-axis collimated light beam are respectively shot into the center of the measurement surface of the corresponding two-dimensional position detector.

[0035] The shape of the light spot projected on the temporary light spot observation screen is required to be circular, the ellipticity is ≤1.1, and the light intensity distribution uniformity is ≥90%. If the light spot shape does not meet the requirements, the laser module and the light path need to be adjusted to make the light spot shape meet the set requirements. This operation avoids the influence of “unqualified light spot” on the subsequent measurement from the source; if the light spot shape is abnormal, the laser point coordinates recorded by the two-dimensional position detector will have a systematic deviation (such as inaccurate positioning of the light spot center), which will further lead to distortion of the trajectory fitting and shape error calculation. Therefore, the pre-calibration of the light spot shape is the basis for ensuring the accuracy of the measurement results.

[0036] In step two, the laser point coordinate value detected by the two-dimensional position detector is The laser point coordinate value corresponds to the plane coordinates of the two-dimensional detector measurement surface, is the X coordinate value of the i-th laser point, is the Y coordinate value of the i-th laser point, j and the corresponding straight line guide is

[0037] After obtaining the laser point coordinate data of each slider at different positions, the obtained data is preprocessed, and abnormal laser point coordinate data is removed.

[0038] The method for removing abnormal laser point coordinate data is as follows:

[0039] First, calculate the X coordinate mean value of the coordinate point cloud data and the Y coordinate mean value ,

[0040] The calculation formula of the X coordinate mean value is as follows:

[0041] ;

[0042] The calculation formula of the Y coordinate mean value The calculation formula of the two-dimensional deviation is as follows:

[0043] ;

[0044] Wherein, n is the number of laser points.

[0045] Then, according to the X coordinate mean value And the Y coordinate mean value The two-dimensional deviation of each laser point coordinate value is calculated ;

[0046] ;

[0047] Then, the two-dimensional deviation mean value is calculated ;

[0048] The calculation formula of the two-dimensional deviation mean value Is as follows:

[0049] ;

[0050] According to the two-dimensional deviation of each laser point coordinate value And the two-dimensional deviation mean value The root mean square error RMSE is calculated;

[0051] ;

[0052] If the two-dimensional deviation of the current laser point coordinate value Is within the interval , the laser point coordinate value is retained; otherwise, the laser point coordinate value is abnormal data and is rejected.

[0053] By rejecting unqualified raw data, the data retention rate of more than 95% is ensured while rejecting abnormal points, and the purification and data integrity are considered, which lays a foundation for subsequent accurate measurement analysis.

[0054] Further, the specific method of step three is as follows:

[0055] S1: The coordinate point cloud data is fitted by the ordinary least squares method to obtain an initial fitting straight line, and the parameters of the initial fitting straight line are taken as initial iteration values to calculate the residual error of each laser point to the initial straight line ;

[0056] Wherein, let the equation of the initial fitting straight line be:

[0057] (1);

[0058] After substituting the laser point coordinate value Into the above formula, the sum of squares of the residual error The formula is as follows:

[0059] (2);

[0060] When is the minimum, the partial derivative of formula (2) with respect to and is taken, and the partial derivative is set to 0, and finally the following is obtained:

[0061] ;

[0062] ;

[0063] wherein:

[0064] ; is the average value of the x coordinates of the points.

[0065] ; is the average value of the y coordinates of the points. ;

[0066] is the sum of squares of deviations from the mean of the x coordinates (i.e., the sum of squares of the differences between the x coordinates and the mean value).

[0067] ;

[0068] is the sum of products of deviations from the mean of the x coordinates and the y coordinates (i.e., the sum of products of the differences between the x coordinates and the mean value and the differences between the y coordinates and the mean value).

[0069] Residual error of the laser point to the initial straight line

[0070] is: .

[0071] .

[0072] S2: Calculate the median of the residual error . When calculating, the residual errors 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, the average value of the two residual values at the middle of the sequence is taken as the median .

[0073] S3: Calculate the absolute deviation of the residual error from the median , and calculate the median of the absolute deviation .​​​ Then the scale parameter is calculated ; scale parameter is the median of the absolute deviation The product of the fixed coefficient f and the absolute deviation; wherein the fixed coefficient f takes the value of 1.4826.

[0074] S4: According to the Huber weight function and in combination with the residual , scale parameter The weight of each laser point coordinate value is calculated ;

[0075] Wherein the Huber weight function is as follows:

[0076] ;

[0077] The value of the fixed coefficient f is 1.345. The greater the residual, the lower the weight of the coordinate point. By assigning a low weight to the point with a large residual, the influence of the abnormal point is reduced.

[0078] S5: Based on the weight The parameters of the fitted straight line are recalculated, and the residual is updated ; repeat steps S2 to S5 until the number of iterations reaches the set number of times, so as to fit the final slider moving trajectory equation.

[0079] Through the fitting calculation of the above method, the slider moving trajectory equation of the first straight line guide is: ; the slider moving trajectory equation of the second straight line guide is: ; the slider moving trajectory equation of the third straight line guide is: .

[0080] The linear fitting process is optimized, and the robust weighted least squares method with linear point cloud Huber weight function is matched with the initial value of the ordinary least squares method, so that the resistance to interference data is enhanced.

[0081] In step four, the form error is calculated: the direction vector of the first straight line guide , the direction vector is perpendicular to the XoZ plane; the direction vector of the second straight line guide , the direction vector is perpendicular to the XoZ plane; the direction vector of the third straight line guide , the direction vector is perpendicular to the YoZ plane. Based on the fitted straight line direction vector and , the parallelism of the first straight line guide and the second straight line guide can be calculated as:

[0082] ;

[0083] The perpendicularity of the first linear guide rail 10 and the third linear guide rail is:

[0084] .

[0085] The utility model still includes data processing module and storage module, after step four is completed, data processing module exports the report containing laser module parameter, two -dimensional position detector collection's original data, parallelism data, perpendicularity data, stores original data with processing result to storage module simultaneously, is used for subsequent quality analysis and traceability.

[0086] The utility model is not limited to the above best implementation, anyone can draw other various forms of product under the enlightenment of the utility model, but no matter make any change in its shape or structure, all have the same or similar technical scheme with the application, fall in the protection scope of the utility model.

Claims

1. A multi-axis form error synchronous measurement apparatus, characterized by, The laser module, a light splitting and turning system, a two-dimensional position detector A arranged on a slider of the first linear guide rail, a two-dimensional position detector B arranged on a slider of the second linear guide rail, and a two-dimensional position detector C arranged on a slider of the third linear guide rail; the light splitting and turning system splits the initial laser output by the laser module into a first Y-axis collimated light beam, a second Y-axis collimated light beam, and a third X-axis collimated light beam, and the first Y-axis collimated light beam, the second Y-axis collimated light beam, and the third X-axis collimated light beam are respectively incident into the two-dimensional position detector A, the two-dimensional position detector B, and the two-dimensional position detector C; the light splitting and turning system comprises a beam splitter A corresponding to the first linear guide rail, a mirror A and a mirror B corresponding to the third linear guide rail, a mirror C corresponding to the second linear guide rail, and a beam splitter B between the beam splitter A and the mirror C, and the beam splitter B corresponds to the mirror B.

2. The multi-axis form error synchronous measurement apparatus of claim 1, wherein, The first Y-axis collimated light beam is parallel to the first linear guide rail, the second Y-axis collimated light beam is parallel to the second linear guide rail, and the third X-axis collimated light beam is parallel to the third linear guide rail.

3. The multi-axis form error synchronous measurement apparatus 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 multi-axis form error synchronous measurement apparatus of claim 1, wherein, The laser module adopts an adjustable power semiconductor laser, and the wavelength of the output laser is 635nm-655nm, and the power range is 1mW-50mW.

5. The multi-axis form error synchronous measurement apparatus of claim 1, wherein, The beam splitter A and the beam splitter B both adopt a non-polarized cubic beam splitter.

6. The multi-axis form error synchronous measurement apparatus of claim 5, wherein, The light splitting ratio of the beam splitter A is 70:30, and the light splitting ratio of the beam splitter B is 50:50.

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