Geometric error detection device for linear axis of machine tool and detection method thereof

Abstract

The application relates to a geometric error detection device of a machine tool linear shaft and a detection method thereof, and the detection device comprises a mirror, an interferometer, an interferometer bidirectional displacement platform, a laser interferometer, a laser interferometer bidirectional displacement platform, a first grating ruler, a second grating ruler and a computer. The mirror is fixed on a Z-direction sliding guide rail of the machine tool, the interferometer is arranged on the interferometer bidirectional displacement platform, the first grating ruler is arranged on the interferometer bidirectional displacement platform and is used for detecting the displacement of the interferometer moving along the X and Y directions; the laser interferometer is arranged on the laser interferometer bidirectional displacement platform, the second grating ruler is arranged on the laser interferometer bidirectional displacement platform and is used for detecting the displacement of the laser interferometer moving along the X and Y directions; and the computer is used for identifying the geometric error value of the machine tool linear shaft according to the spatial position coordinates. The technical scheme has higher measurement precision and wider measurement bandwidth, the measurement time is short, and the requirement of rapid measurement is met.

Description

Technical Field

[0001] This application relates to the field of precision machine tool technology, and in particular to a geometric error detection device and method for a linear axis of a machine tool. Background Technology

[0002] With the increasing demands for precision parts machining in industries such as aerospace, military, shipbuilding, and automotive, the precision performance of machine tools has become increasingly important, leading to a surge in research on improving the precision of CNC machine tools. Dimensional accuracy is the most crucial factor determining the machining accuracy of CNC machine tools, and the geometric accuracy of CNC machine tools is the direct cause affecting dimensional accuracy. Error measurement, as a fundamental aspect of improving the geometric accuracy of machine tools, has made accurate measurement and identification of error terms a focus of attention for scholars both domestically and internationally.

[0003] Methods for identifying geometric errors in the motion platform of CNC machine tools have emerged, including the 9-line method, the 10-line method, the 14-line method, the laser tracking method, the comprehensive error verification of coordinate measuring machines based on laser interferometers, and the step-by-step diagonal method based on Kepler laser interferometers. However, these methods lack analysis of the impact of the positional error of the measuring instrument on the identification results. For example, the errors inherent in the laser interferometer itself during measurement also lead to poor identification accuracy or even unreliability. In some high-precision measurement applications, the identification accuracy is far from meeting the requirements. Summary of the Invention

[0004] To address one of the aforementioned shortcomings, this application provides a geometric error detection device and method for machine tool linear axes, thereby improving measurement efficiency and identification accuracy.

[0005] A geometric error detection device for a linear axis of a machine tool includes: a reflector, an interferometer, a bidirectional displacement platform for the interferometer, a laser interferometer, a bidirectional displacement platform for the laser interferometer, a first grating ruler, a second grating ruler, and a computer;

[0006] The reflector is fixed on the Z-axis sliding guide rail of the machine tool and moves along the Z-axis sliding guide rail of the machine tool;

[0007] The interferometer is mounted on a bidirectional displacement platform for moving the interferometer; the first grating ruler is mounted on the bidirectional displacement platform for detecting the displacement of the interferometer along the X and Y directions.

[0008] The laser interferometer is mounted on a two-way displacement platform for moving the laser interferometer; the second grating ruler is mounted on the two-way displacement platform for detecting the displacement of the laser interferometer along the X and Y directions.

[0009] The reflectors are arranged sequentially at multiple detection positions on the measurement trajectory of the machine tool motion platform; the relative positions of the interferometer on the bidirectional displacement platform and the laser interferometer on the bidirectional displacement platform are such that the reflectors and the interferometer are on the same measurement line.

[0010] The computer is used to acquire the positioning data measured by the laser interferometer at each detection position of the reflector and the displacement measured by the first grating ruler and the second grating ruler. Based on the positioning data and displacement, the computer acquires the spatial position coordinates corresponding to the reflector and identifies the geometric error value of the machine tool linear axis based on the spatial position coordinates.

[0011] In one embodiment, the interferometer bidirectional displacement platform includes: an interferometer tilting turntable, an interferometer pitching turntable, an interferometer X-axis moving axis, an interferometer Y-axis moving axis, and an interferometer moving base.

[0012] The interferometer is fixed on the interferometer tilting turntable, and the interferometer pitching turntable is used to adjust the pitch angle of the interferometer tilting turntable; the interferometer X-axis is used for movement in the X-axis direction, and the interferometer Y-axis is used for movement in the Y-axis direction.

[0013] The first grating ruler includes an X-axis grating ruler and a Y-axis grating ruler fixed on the X-axis and Y-axis of the interferometer, respectively. The X-axis grating ruler and the Y-axis grating ruler are used to detect the displacement of the interferometer along the X-axis and Y-axis, respectively.

[0014] In one embodiment, the laser interferometer bidirectional displacement platform includes: a laser interferometer yaw turntable, a laser interferometer pitch turntable, a laser interferometer X-axis, a laser interferometer Y-axis, and a laser interferometer base frame;

[0015] The laser interferometer is fixed on the laser interferometer tilting turntable, and the laser interferometer pitching turntable is used to adjust the pitch angle of the laser interferometer tilting turntable; the laser interferometer X-axis is used to move in the X-axis direction, and the laser interferometer Y-axis is used to move in the Y-axis direction.

[0016] The second grating ruler includes a laser interferometer X-axis grating ruler and a laser interferometer Y-axis grating ruler, which are respectively fixed on the X-axis and Y-axis of the laser interferometer. The laser interferometer X-axis grating ruler and the laser interferometer Y-axis grating ruler are used to detect the displacement of the laser interferometer along the X-axis and Y-axis directions, respectively.

[0017] In one embodiment, the reflector is arranged at 5 detection positions on the XY plane of the machine tool motion platform, and the reflector is used to detect multiple measurement points in the Z-axis direction at the 5 detection positions;

[0018] The bidirectional displacement platform for the interferometer mirror moves the interferometer mirror to five detection positions on the XY plane via the X-axis and Y-axis of the interferometer mirror, respectively.

[0019] The X-axis grating ruler and the Y-axis grating ruler of the interferometer respectively detect the first X-axis displacement and the first Y-axis displacement of the interferometer along the X-axis and Y-axis directions;

[0020] The laser interferometer bidirectional displacement platform moves the laser interferometer to five detection positions on the XY plane via the X-axis and Y-axis of the laser interferometer.

[0021] The X-axis grating ruler and Y-axis grating ruler of the laser interferometer detect the second X-axis displacement and the second Y-axis displacement of the laser interferometer moving along the X-axis and Y-axis directions, respectively.

[0022] In one embodiment, the computer is used to acquire the preset spatial position coordinates of the reflector, acquire the Z-axis displacement based on the positioning data of the laser interferometer, acquire the first position coordinates of the interferometer based on the first X-axis displacement and the first Y-axis displacement, acquire the second position coordinates of the laser interferometer based on the second X-axis displacement and the second Y-axis displacement; calculate the error data of the machine tool linear axis based on the preset spatial position coordinates, the Z-axis displacement, the first position coordinates, and the second position coordinates, and identify six geometric errors of the machine tool linear motion axis based on the error data.

[0023] In one embodiment, the computer is further configured to:

[0024] The second spatial position range of the laser interferometer in the machine tool motion platform is obtained. The second error compensation amount of the second grating ruler is calculated according to the preset second spatial position range and the second grating ruler error model. The second X-axis displacement and the second Y-axis displacement are corrected according to the second error compensation amount. The second grating ruler error model is used to calculate the error value introduced by the second grating ruler when the laser interferometer is in different spatial position ranges.

[0025] The first spatial position range of the interferometer in the machine tool motion platform is obtained, and the first error compensation amount of the first grating ruler is calculated according to the preset first spatial position range and the first grating ruler error model. The first X-axis displacement and the first Y-axis displacement are corrected according to the first error compensation amount. The first grating ruler error model is used to calculate the error value introduced by the first grating ruler when the interferometer is in different spatial position ranges.

[0026] as well as

[0027] The first position coordinates of the interferometer are obtained based on the corrected first X-axis displacement and first Y-axis displacement, and the second position coordinates of the laser interferometer are obtained based on the corrected second X-axis displacement and second Y-axis displacement.

[0028] A method for detecting the geometric error of a machine tool linear axis, applied to the aforementioned geometric error detection device for the machine tool linear axis, characterized in that it includes:

[0029] The measurement trajectory of the machine tool motion axis is designed based on the geometric error model of the machine tool motion, and the reflector is moved to the initial detection position on the measurement trajectory;

[0030] The reflector is moved from the initial detection position to each measurement point via the Z-axis sliding guide rail;

[0031] The positioning data measured by the laser interferometer and the displacement measured by the first and second grating rulers are obtained sequentially at each measurement point.

[0032] Move the reflector to the next detection position on the measurement trajectory, and measure each measurement point again until all detection positions are measured.

[0033] The actual spatial coordinates of the reflector are obtained based on the positioning data and displacement measured at each measurement point of each detection location.

[0034] The error data of the corresponding detection position is calculated based on the preset spatial position coordinates of each measurement point and the measured spatial position coordinates. The six geometric error values ​​of the machine tool linear axis are identified based on the error data of each detection position.

[0035] In one embodiment, the geometric error equation is represented by formula ①:

[0036]

[0037] in, This indicates that at position i, Indicates the initial position ( x, y, z ), δX(Z), δY(Z), δZ(Z), εX (Z), εY(Z), εZ(Z) These are the six geometric errors of a single linear axis of a machine tool.

[0038] In one embodiment, the equation measured by the laser interferometer includes the following formula ②:

[0039]

[0040] in,[ [ represents the initial position coordinates, [] [This refers to the position of the reflector at the corresponding detection location.] k ( k= The preset spatial coordinates of positions 1, 2, 3, 4, and 5, [ [These represent the X-axis straightness error, Y-axis straightness error, and Z-axis positioning error, actually measured using a laser interferometer.] i Indicates the location number of the measurement point, [ This represents the error data between the machine tool's preset value and the actual measured value of the laser interferometer.

[0041] In one embodiment, six geometric error values ​​of the machine tool linear axis are identified based on error data from each detection location, including:

[0042]

[0043]

[0044]

[0045]

[0046] in, Indicates the error data item. Represents the identity matrix. An antisymmetric matrix representing the spatial position of the mirror relative to the machine tool;

[0047] These are the six geometric errors of the machine tool's linear axis.

[0048] The technical solution of this application has the following technical effects:

[0049] This application uses a grating ruler to quickly measure the displacement of a laser interferometer along the X and Y directions. Based on the characteristic that the reflectors are on the same measurement line, the spatial position coordinates of the reflectors on the machine tool motion platform are finally obtained. This technical solution overcomes the defect that the position matrix is ​​sensitive to position errors. By using a grating ruler as a measuring element, it avoids the position error of the analysis measuring instrument, thus achieving higher measurement accuracy and a wider measurement bandwidth. The measurement time is short, meeting the requirements of rapid measurement.

[0050] Additional aspects and advantages of this application will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0051] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0052] Figure 1 This is a schematic diagram of the structure of a geometric error detection device for a linear axis of a machine tool, according to one embodiment.

[0053] Figure 2 This is a schematic diagram of an example interferometer bidirectional displacement platform structure;

[0054] Figure 3 This is a schematic diagram of an example laser interferometer bidirectional displacement platform structure;

[0055] Figure 4 This is a flowchart of a geometric error detection method for a linear axis of a machine tool, according to one embodiment.

[0056] Figure 5 This is a schematic diagram of an example measurement trajectory;

[0057] Figure 6 This is a schematic diagram illustrating an example of error identification comparison. Detailed Implementation

[0058] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0059] Those skilled in the art will understand that, unless otherwise stated, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the word “comprising” as used in the specification of this application means the presence of the stated feature, integer, step, or operation, but does not exclude the presence or addition of one or more other features, integers, steps, or operations.

[0060] In the geometric error detection of linear axes of machine tools, indirect measurement generally involves positioning and straightness measurement at several locations in space, then establishing a comprehensive error identification model and solving the model to obtain a total of six geometric errors for a single axis.

[0061] The common error calculation matrix requires the spatial location matrix to be obtained in advance. A typical spatial location matrix is ​​shown below:

[0062]

[0063] In the formula, (X 1 ，Y 1 ，Z 1 )、(X 2 ，Y 2 ，Z 2 )、(X 3 ，Y 3 ，Z 3 ) These are the spatial coordinates of reflector 01 on a single axis of the machine tool. δX(X), δY(X), δZ(X), εX(x), εY(x), εZ(x) These are the six geometric errors of a single axis of a machine tool, namely, the positioning error along the X-axis in the X-axis direction, the displacement error along the X-axis in the Y-axis direction, the displacement error along the X-axis in the Z-axis direction, the rolling error along the X-axis in the X-axis direction, the torsional error along the X-axis in the Y-axis direction, and the rotational error along the X-axis in the Z-axis direction.

[0064] If there is a large placement error when recording the spatial coordinates of the measurement points in the matrix above, and if the condition number of the position matrix is ​​too large, it will affect the accuracy of the six geometric errors of the machine tool single axis and fail to meet the requirements of high-precision measurement applications.

[0065] Accordingly, this application provides a geometric error detection device for a machine tool linear axis, with reference to... Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of a geometric error detection device for a linear axis of a machine tool according to one embodiment, including: a reflector 01, an interferometer 02, a bidirectional displacement platform for the interferometer 03, a laser interferometer 05, a bidirectional displacement platform for the laser interferometer 06, a first grating ruler 07, a second grating ruler 08, and a computer 09.

[0066] like Figure 1 As shown, the reflector 01 is fixed on the Z-axis sliding guide rail 04 of the machine tool and moves along the Z-axis sliding guide rail 04 of the machine tool; the reflector 01 moves linearly through the Z-axis sliding guide rail 04.

[0067] Interferometer 02 is mounted on interferometer bidirectional displacement platform 03, which is used to move interferometer 02; first grating ruler 07 is mounted on interferometer bidirectional displacement platform 03 and is used to detect the displacement of interferometer 02 along the X and Y directions.

[0068] The laser interferometer 05 is mounted on the laser interferometer bidirectional displacement platform 06, which is used to move the laser interferometer 05. The second grating ruler 08 is mounted on the laser interferometer bidirectional displacement platform 06 and is used to detect the displacement of the laser interferometer 05 along the X and Y directions.

[0069] The reflector 01 is arranged sequentially at multiple detection positions on the measurement trajectory of the machine tool motion platform; the interferometer bidirectional displacement platform 03 moves the interferometer 02 and the laser interferometer bidirectional displacement platform 06 moves the laser interferometer 05 in the relative positions of the machine tool motion platform, so that the reflector 01 and the interferometer 02 are on the same measurement line;

[0070] Computer 09 is used to acquire the positioning data measured by laser interferometer 05 at each detection position of reflector 01 and the displacement measured by first grating ruler 07 and second grating ruler 08 to obtain the spatial position coordinates of reflector 01, and to identify the geometric error value of machine tool linear axis based on the spatial position coordinates.

[0071] As described in the above embodiment, the grating ruler is used to quickly measure the displacement of the laser interferometer 05 along the X and Y directions. Based on the characteristic that the reflector 01 is on the same measurement line, the spatial position coordinates of the reflector 01 on the machine tool motion platform are finally obtained. This overcomes the defect that the position matrix is ​​sensitive to position errors. By using the grating ruler as a measuring element, the position error of the analysis measuring instrument is avoided, thus achieving higher measurement accuracy and a wider measurement bandwidth. The measurement time is short, meeting the requirements of rapid measurement.

[0072] In one embodiment, for the interferometer bidirectional displacement platform 03, such as Figure 2 As shown, Figure 2 This is a schematic diagram of an example interferometer bidirectional displacement platform structure, which may include: an interferometer tilting turntable 31, an interferometer pitching turntable 32, an interferometer X-axis moving axis 33, an interferometer Y-axis moving axis 34, and an interferometer moving base 35.

[0073] Interferometer 02 is fixed on interferometer tilting turntable 31. Interferometer tilting turntable 31 is used to rotate interferometer 02, and interferometer pitch turntable 32 is used to adjust pitch angle. Interferometer X-axis 33 is used to move in the X-axis direction, and interferometer Y-axis 34 is used to move in the Y-axis direction.

[0074] The first grating ruler 07 includes an X-axis grating ruler 71 and a Y-axis grating ruler 72 of the interferometer mirror, which are respectively fixed on the X-axis moving axis 33 and the Y-axis moving axis 34 of the interferometer mirror. The X-axis grating ruler 71 and the Y-axis grating ruler 72 of the interferometer mirror are used to detect the displacement of the interferometer mirror 02 along the X-axis and Y-axis directions, respectively.

[0075] In one embodiment, for the bidirectional displacement platform 06 of the laser interferometer, such as Figure 3 As shown, Figure 3 This is a schematic diagram of the structure of a two-way displacement platform 06 for a laser interferometer, which may include: a yaw turntable 61 for the laser interferometer, a pitch turntable 62 for the laser interferometer, an X-axis moving axis 63 for the laser interferometer, a Y-axis moving axis 64 for the laser interferometer, and a moving base frame 65 for the laser interferometer.

[0076] The laser interferometer 05 is fixed on the laser interferometer tilting turntable 61. The laser interferometer tilting turntable 61 is used to rotate the laser interferometer 05, and the laser interferometer pitch turntable 62 is used to adjust the pitch angle. The laser interferometer X-axis 63 is used to move in the X-axis direction, and the laser interferometer Y-axis 64 is used to move in the Y-axis direction.

[0077] The second grating ruler 08 includes a laser interferometer X-axis grating ruler 81 and a laser interferometer Y-axis grating ruler 82, which are respectively fixed on the X-axis moving axis 63 and the Y-axis moving axis 64 of the laser interferometer. The laser interferometer X-axis grating ruler 81 and the laser interferometer Y-axis grating ruler 82 are used to detect the displacement of the laser interferometer 05 along the X-axis and Y-axis directions, respectively.

[0078] As described in the above embodiment, a laser interferometer bidirectional displacement platform 06 and an interferometer bidirectional displacement platform 03 with specific structures are designed. A grating ruler is used to quickly measure the displacement of the laser interferometer 05 and the interferometer 02 along the X and Y axes. Based on the characteristic that the reflector 01 is on the same measurement line, the laser interferometer 05 is used to position the Z axis. The spatial coordinates of the reflector 01 on the machine tool motion platform are finally obtained by combining the displacement measured by the grating ruler with the positioning data of the laser interferometer 05. The use of a grating ruler as a measuring element in the X and Y axes has high measurement accuracy and a wide measurement bandwidth, which meets the requirements of rapid measurement.

[0079] In one embodiment, a 5-point measurement method can be used during measurement, selecting 5 positions in the machine tool space for comprehensive error measurement, and finally identifying the six geometric errors of the machine tool's linear motion axis.

[0080] Specifically, reflector 01 is positioned at five detection positions on the XY plane of the machine tool motion platform, and multiple measurement points are measured along the Z-axis at these five detection positions. During measurements between detection positions, the interferometer bidirectional displacement platform 03 moves interferometer 02 along the X and Y axes to the five detection positions on the XY plane via interferometer X-axis movement axis 33 and interferometer Y-axis movement axis 34, respectively. Interferometer X-axis grating ruler 71 and interferometer Y-axis grating ruler 72 detect the first X-axis displacement and the first Y-axis displacement of interferometer 02 along the X and Y axes, respectively. The laser interferometer bidirectional displacement platform 06 moves laser interferometer 05 to the five detection positions on the XY plane via laser interferometer X-axis movement axis 63 and laser interferometer Y-axis movement axis; laser interferometer X-axis grating ruler 81 and laser interferometer Y-axis grating ruler 82 detect the second X-axis displacement and the second Y-axis displacement of laser interferometer 05 along the X and Y axes.

[0081] Since five detection positions are preset, the reflector 01 can be moved to the corresponding detection position by controlling the movement of the machine tool in the XY plane. By combining the displacement of the interferometer 02 in the X and Y axes and the displacement of the laser interferometer 05 in the X and Y axes, the actual displacement data of the reflector 01 in the X and Y axes can be accurately measured. This avoids the measurement error caused by using the positioning data of the laser interferometer 05 alone, and thus avoids the influence of the position error of the analysis and measurement instrument on the identification results.

[0082] In one embodiment, for the use of the geometric error detection device for the linear axis of a machine tool, the computer 09 can be configured to acquire the preset spatial position coordinates of the reflector 01, acquire the Z-axis displacement based on the positioning data of the laser interferometer 05, acquire the first position coordinates of the interferometer 02 based on the first X-axis displacement and the first Y-axis displacement, acquire the second position coordinates of the laser interferometer 05 based on the second X-axis displacement and the second Y-axis displacement, calculate the error data of the linear axis of the machine tool based on the preset spatial position coordinates, the Z-axis displacement, the first position coordinates, and the second position coordinates, and identify the six geometric errors of the linear motion axis of the machine tool based on the error data.

[0083] To further improve the accuracy of identifying geometric errors in the linear motion axes of machine tools, the grating ruler used was modified to compensate for the error introduced by the grating ruler, thereby making the displacement measured in the X-axis direction more accurate.

[0084] Accordingly, in one embodiment, the geometric error detection device for the linear axis of the machine tool of this application, wherein the computer 09 is further configured to execute the following processing flow:

[0085] (1) Obtain the second spatial position range of the laser interferometer 05 in the machine tool motion platform, calculate the second error compensation amount of the second grating ruler 08 according to the preset second spatial position range and the error model of the second grating ruler 08, and correct the second X-axis displacement and the second Y-axis displacement according to the second error compensation amount; wherein, the error model of the second grating ruler 08 is used to calculate the error value introduced by the second grating ruler 08 when the laser interferometer 05 is in different spatial position ranges; the error model of the second grating ruler 08 can be obtained by fitting the error data of the bidirectional displacement platform 06 of the laser interferometer.

[0086] (2) Obtain the first spatial position range of the interferometer 02 in the machine tool motion platform, calculate the first error compensation amount of the first grating ruler 07 according to the preset first spatial position range and the error model of the first grating ruler 07, and correct the first X-axis displacement and the first Y-axis displacement according to the first error compensation amount; wherein, the error model of the first grating ruler 07 is used to calculate the error value introduced by the first grating ruler 07 when the interferometer 02 is in different spatial position ranges; the error model of the first grating ruler 07 can be obtained by fitting the statistical error data of the bidirectional displacement platform 03 of the interferometer.

[0087] (3) Obtain the first position coordinates of the interferometer 02 based on the corrected first X-axis displacement and first Y-axis displacement, and obtain the second position coordinates of the laser interferometer 05 based on the corrected second X-axis displacement and second Y-axis displacement.

[0088] As described in the above embodiment, by pre-designing the error model of the first grating ruler 07 and the error model of the second grating ruler 08 based on the spatial position relationship, the error values ​​introduced by the first grating ruler 07 and the second grating ruler 08 are calculated respectively. In this way, the errors of the first grating ruler 07 and the second grating ruler 08 are eliminated during the measurement process, so that the displacement in the X and Y axis directions can be measured more accurately, and the identification accuracy of the geometric error of the linear motion axis of the machine tool is improved.

[0089] refer to Figure 4 As shown, Figure 4 This is a flowchart of a geometric error detection method for a machine tool linear axis according to one embodiment. The method is applied to the geometric error detection device for a machine tool linear axis of this application and includes:

[0090] s1, Design the measurement trajectory of the machine tool motion axis according to the geometric error model of the machine tool motion, and move the reflector 01 to the initial detection position on the measurement trajectory;

[0091] s2, at the initial detection position, move the reflector 01 to each measurement point via the Z-axis sliding guide rail 04;

[0092] s3, sequentially acquire the positioning data measured by the laser interferometer 05 corresponding to each measurement point, as well as the displacement measured by the first grating ruler 07 and the second grating ruler 08;

[0093] s4, determine if all measurement points have been measured? If yes, execute s5; otherwise, continue executing s3.

[0094] s5, move reflector 01 to the next detection position on the measurement trajectory, and jump to execute s3;

[0095] s6, Determine if all detection positions have been completed. If yes, proceed to s7; otherwise, continue with s5.

[0096] s7, based on the positioning data and displacement detected at each measurement point of each detection position, obtain the actual spatial position coordinates corresponding to the reflector 01;

[0097] s8 calculates the error data of the corresponding detection position based on the preset spatial position coordinates and the actual spatial position coordinates of each measurement point, and identifies the six geometric error values ​​of the machine tool linear axis based on the error data of each detection position.

[0098] In one embodiment, the reflector 01 moves along the Z direction, and its geometric error equation is expressed by formula ①:

[0099]

[0100] in, This indicates that at position i, Indicates the initial position ( x, y, z ), δX(Z), δY(Z), δZ(Z), εX (Z), εY(Z), εZ(Z) These are the six geometric errors of a single linear axis of a machine tool.

[0101] In one embodiment, five detection positions are selected in the machine tool space for comprehensive error measurement, with reference to... Figure 5 As shown, Figure 5 This is a schematic diagram of an example measurement trajectory, including the positioning error measurement at each detection position, the X-axis straightness measurement, and the Y-axis straightness measurement corresponding to that detection position; the equation for the measurement by the laser interferometer 05 at a certain position includes the following formula ②:

[0102]

[0103] in,[ [ represents the initial position coordinates, [] [This refers to the position of mirror 01 at the corresponding detection location.] k ( k= The preset spatial coordinates of positions 1, 2, 3, 4, and 5, [ [These are the X-axis straightness error, Y-axis straightness error, and Z-axis positioning error actually measured using a laser interferometer 05.] i Indicates the location number of the measurement point, [ This represents the error data between the machine tool's preset value and the actual measured value of the laser interferometer 05.

[0104] For example, take position 1 as an example:

[0105]

[0106] In the above formula, [ The spatial coordinates of the reflector 01 at detection position 1 are preset, and the same calculation operation is performed for detection positions 2, 3, 4, and 5 to obtain the corresponding comprehensive error values.

[0107] In one embodiment, for the six geometric error values ​​of the machine tool linear axis identified based on the error data of each detection position, combined with the comprehensive error value of each detection position calculated in the above example, the comprehensive error value obtained from the five detection positions can be expressed as follows:

[0108]

[0109] Based on formulas ①, ②, and ③, the six geometric errors of the machine tool linear axis can be obtained:

[0110]

[0111]

[0112] in, Indicates the error data item. Represents the identity matrix. The antisymmetric matrix represents the spatial position of mirror 01 relative to the machine tool.

[0113]

[0114] in, These are the six geometric errors of the machine tool's linear axis.

[0115] Using the least squares method, we can obtain formula ⑤:

[0116]

[0117]

[0118]

[0119] Combining the above formula ⑤, it can be seen that by measuring the positioning errors of the machine tool at five positions, as well as the straightness errors in the X and Y directions, the six geometric errors of a single axis of the machine tool can be solved. Furthermore, due to the increased measurement of error data, even if an error is introduced at a single detection position, its impact on the identification of the overall error is relatively small. For example... Figure 6 As shown, Figure 6 This is an example error identification comparison diagram, comparing the difference between the geometric error detected using the technical solution provided in this application and the traditional technical solution and the actual deviation value. Line segment A represents the technical solution of this application, and line segment B represents the traditional technical solution. As can be seen from the comparison, the technical solution of this application has high measurement accuracy and can quickly measure the displacement of the laser interferometer 02 group along the X and Y directions. Combined with the provided algorithm, it can accurately calculate the six geometric errors of the machine tool linear axis.

[0120] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A geometric error detection device for a linear axis of a machine tool, characterized in that, include: Reflector (01), interferometer (02), interferometer bidirectional displacement platform (03), laser interferometer (05), laser interferometer bidirectional displacement platform (06), first grating ruler (07), second grating ruler (08), and computer (09); The reflector (01) is fixed on the Z-axis sliding guide rail (04) of the machine tool and moves along the Z-axis sliding guide rail (04) of the machine tool; The interferometer (02) is mounted on the bidirectional displacement platform (03), which is used to move the interferometer (02); the first grating ruler (07) is mounted on the bidirectional displacement platform (03) and is used to detect the displacement of the interferometer (02) along the X and Y directions. The laser interferometer (05) is mounted on the laser interferometer bidirectional displacement platform (06), which is used to move the laser interferometer (05); the second grating ruler (08) is mounted on the laser interferometer bidirectional displacement platform (06) and is used to detect the displacement of the laser interferometer (05) along the X and Y directions; The reflector (01) is arranged in sequence at multiple detection positions on the measurement trajectory of the machine tool motion platform; the bidirectional displacement platform (03) of the interferometer moves the interferometer (02) and the bidirectional displacement platform (06) of the laser interferometer moves the laser interferometer (05) in the relative position of the machine tool motion platform, so that the reflector (01) and the interferometer (02) are on the same measurement line; The computer (09) is used to acquire the positioning data measured by the laser interferometer (05) corresponding to each detection position of the reflector (01) and the displacement measured by the first grating ruler (07) and the second grating ruler (08), to acquire the spatial position coordinates corresponding to the reflector (01) based on the positioning data and the displacement, and to identify the geometric error value of the machine tool linear axis based on the spatial position coordinates. The bidirectional displacement platform (03) of the interferometer includes: an interferometer tilting turntable (31), an interferometer pitching turntable (32), an interferometer X-axis moving axis (33), an interferometer Y-axis moving axis (34), and an interferometer moving base (35). The interferometer (02) is fixed on the interferometer tilting turntable (31), and the interferometer pitching turntable (32) is used to adjust the pitch angle of the interferometer tilting turntable (31); the interferometer X-axis moving axis (33) is used to move in the X-axis direction, and the interferometer Y-axis moving axis (34) is used to move in the Y-axis direction. The first grating ruler (07) includes an interferometer X-axis grating ruler (71) and an interferometer Y-axis grating ruler (72) fixed on the interferometer X-axis moving axis (33) and the interferometer Y-axis moving axis (34), respectively. The interferometer X-axis grating ruler (71) and the interferometer Y-axis grating ruler (72) are used to detect the displacement of the interferometer (02) along the X-axis and Y-axis directions, respectively. The laser interferometer bidirectional displacement platform (06) includes: a laser interferometer yaw turntable (61), a laser interferometer pitch turntable (62), a laser interferometer X-axis moving axis (63), a laser interferometer Y-axis moving axis (64), and a laser interferometer moving base (65). The laser interferometer (05) is fixed on the laser interferometer tilting turntable (61), the laser interferometer pitching turntable (62) is used to adjust the pitch angle of the laser interferometer tilting turntable (61); the laser interferometer X-axis (63) is used to move in the X-axis direction, and the laser interferometer Y-axis (64) is used to move in the Y-axis direction. The second grating ruler (08) includes a laser interferometer X-axis grating ruler (81) and a laser interferometer Y-axis grating ruler (82) respectively fixed on the X-axis moving axis (63) and the Y-axis moving axis (64) of the laser interferometer. The laser interferometer X-axis grating ruler (81) and the laser interferometer Y-axis grating ruler (82) are used to detect the displacement of the laser interferometer (05) along the X-axis and Y-axis directions, respectively.

2. The geometric error detection device for machine tool linear axes according to claim 1, characterized in that, The reflector (01) is arranged at 5 detection positions on the XY plane of the machine tool motion platform, and the reflector (01) is used to detect multiple measurement points in the Z-axis direction of the 5 detection positions; The bidirectional displacement platform (03) of the interferometer moves the interferometer (02) to five detection positions on the XY plane in the X-axis and Y-axis directions respectively via the interferometer X-axis (33) and the interferometer Y-axis (34); The X-axis grating ruler (71) and the Y-axis grating ruler (72) of the interferometer mirror respectively detect the first X-axis displacement and the first Y-axis displacement of the interferometer mirror (02) along the X-axis and Y-axis directions; The laser interferometer bidirectional displacement platform (06) moves the laser interferometer (05) to five detection positions on the XY plane via the X-axis (63) and Y-axis of the laser interferometer (05). The X-axis grating ruler (81) and Y-axis grating ruler (82) of the laser interferometer detect the second X-axis displacement and the second Y-axis displacement of the laser interferometer (05) moving along the X-axis and Y-axis directions.

3. The geometric error detection device for machine tool linear axes according to claim 2, characterized in that, The computer (09) is used to obtain the preset spatial position coordinates of the reflector (01), obtain the Z-axis displacement based on the positioning data of the laser interferometer (05), obtain the first position coordinates of the interferometer (02) based on the first X-axis displacement and the first Y-axis displacement, and obtain the second position coordinates of the laser interferometer (05) based on the second X-axis displacement and the second Y-axis displacement; calculate the error data of the machine tool linear axis based on the preset spatial position coordinates, the Z-axis displacement, the first position coordinates and the second position coordinates, and identify the six geometric errors of the machine tool linear motion axis based on the error data; the six geometric errors include the machine tool positioning error along the X-axis in the X-axis direction, the displacement error along the X-axis in the Y-axis direction, the displacement error along the X-axis in the Z-axis direction, the rolling error along the X-axis in the X-axis direction, the torsional error along the X-axis in the Y-axis direction, and the rotation error along the X-axis in the Z-axis direction.

4. The geometric error detection device for a machine tool linear axis according to claim 3, characterized in that, The computer (09) is also used for: The second spatial position range of the laser interferometer (05) in the machine tool motion platform is obtained. The second error compensation amount of the second grating ruler (08) is calculated according to the preset second spatial position range and the error model of the second grating ruler (08). The second X-axis displacement and the second Y-axis displacement are corrected according to the second error compensation amount. The error model of the second grating ruler (08) is used to calculate the error value introduced by the second grating ruler (08) when the laser interferometer (05) is in different spatial position ranges. Obtain the first spatial position range of the interferometer (02) in the machine tool motion platform, calculate the first error compensation amount of the first grating ruler (07) according to the preset first spatial position range and the error model of the first grating ruler (07), and correct the first X-axis displacement and the first Y-axis displacement according to the first error compensation amount; wherein, the error model of the first grating ruler (07) is used to calculate the error value introduced by the first grating ruler (07) when the interferometer (02) is in different spatial position ranges; as well as The first position coordinates of the interferometer (02) are obtained based on the corrected first X-axis displacement and first Y-axis displacement, and the second position coordinates of the laser interferometer (05) are obtained based on the corrected second X-axis displacement and second Y-axis displacement.

5. A method for detecting the geometric error of a machine tool linear axis, applied to the geometric error detection device for a machine tool linear axis as described in any one of claims 4, characterized in that, include: The measurement trajectory of the machine tool motion axis is designed based on the geometric error model of the machine tool motion, and the reflector (01) is moved to the initial detection position on the measurement trajectory; Move the reflector (01) to each measurement point via the Z-axis sliding guide rail (04) from the initial detection position; The positioning data measured by the laser interferometer (05) and the displacement measured by the first grating ruler (07) and the second grating ruler (08) are obtained sequentially for each measurement point; Move the reflector (01) to the next detection position on the measurement trajectory, and measure each measurement point again until all detection positions are measured; The measured spatial coordinates of the reflector (01) are obtained based on the positioning data and displacement measured at each measurement point of each detection location. The error data of the corresponding detection position is calculated based on the preset spatial position coordinates of each measurement point and the measured spatial position coordinates. The six geometric error values ​​of the machine tool linear axis are identified based on the error data of each detection position. The geometric error equation is expressed by formula ①: ; in, This indicates that at position i, Indicates the initial position ( x, y, z ), δX(Z), δY(Z), δZ(Z), εX(Z), ε Y(Z), εZ(Z) These are the six geometric errors of a single linear axis of a machine tool.

6. The method for detecting geometric errors of a machine tool linear axis according to claim 5, characterized in that, The equations measured by the laser interferometer (05) include the following formula ②: ; in,[ ] represents the initial position coordinates of the reflector (01), [ [The mirror (01) is at the corresponding detection position] k ( k= The preset spatial coordinates of positions 1, 2, 3, 4, and 5, [ [The values ​​represent the X-axis straightness error, Y-axis straightness error, and Z-axis positioning error, which were actually measured using a laser interferometer (05).] i Indicates the location number of the measurement point, [ [This refers to the error data between the preset value of the machine tool and the actual measured value of the laser interferometer (05).] 7. The method for detecting geometric errors of a machine tool linear axis according to claim 6, characterized in that, Based on the error data from each detection location, six geometric error values ​​for the machine tool linear axis were identified, including: ; ; ; ; in, Indicates the error data item. Represents the identity matrix. The antisymmetric matrix representing the spatial position of the reflector (01) relative to the machine tool; These are the six geometric errors of the machine tool's linear axis.

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