Method for detecting and compensating motion error of three-axis numerical control machine tool based on detection test piece

Abstract

The present application relates to a kind of three-axis numerical control machine tool movement error detection and compensation method based on detection test piece, by the identification of nine movement errors of high-precision three-axis numerical control machine tool XYZ axis, the movement error obtained by identification is used to predict machining error to obtain compensation data, error compensation is carried out.The present application obtains the movement error difficult to directly measure on high-precision three-axis numerical control machine tool by the geometry error calculation easy to measure on detection test piece, and can predict the geometry error of any position in machining space by the obtained movement error, which is beneficial to improve work efficiency and improve machining precision.The calculation process is reasonably simplified, which can effectively improve the detection efficiency.The present application uses different parts to detect on a single material test piece, improves the use rate of test piece, and the test piece structure is simple, which is convenient for machine tool machining.The test piece can adapt to different machine tool operating systems and can be applied to error detection of high-precision three-axis numerical control machine tools of different sizes.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of three-axis numerical control machine tool movement error detection technology, in particular to a kind of three-axis numerical control machine tool test piece design and based on the high-precision three-axis numerical control machine tool movement error detection and compensation method of test piece. BACKGROUND

[0002] In recent years, mechanical manufacturing industry is developing rapidly towards precision machining. Improving machining precision is conducive to improving product performance and quality, improving its quality stability and performance reliability. And high-precision three-axis numerical control machine tool is one of the most common machining equipment in mechanical manufacturing industry. With its relatively low cost and multifunctionality of operation, it is widely used in manufacturing industry, and it can quickly process various geometric parts. Three-axis numerical control machining process uses rotary cutter moving along three axes to process fixed workpiece, and cutting tool moves along X, Y and Z axes to trim excess material on the workpiece.

[0003] During the working process of high-precision three-axis numerical control machine tool, the actual movement trajectory of its main moving parts such as worktable and spindle will deviate from the ideal movement trajectory, resulting in inaccurate machining precision. Error detection (also known as error identification) of main movement error of high-precision three-axis numerical control machine tool helps to perform error calibration or error compensation, thereby improving machining precision and obtaining higher precision machined parts. SUMMARY

[0004] In order to calibrate the precision of high-precision three-axis numerical control machine tool and improve the accuracy of machine tool machining, the present application proposes a test piece for detecting movement error of three-axis numerical control machine tool and a three-axis numerical control machine tool movement error detection and compensation method based on test piece.

[0005] The technical solution of the present application is: a three-axis numerical control machine tool movement error detection and compensation method based on test piece, which adopts a test piece for detecting movement error of three-axis numerical control machine tool. The geometric structure of the test piece includes a base, a stepped structure on the base, and a circular feature hole structure arranged on the base and the stepped structure. The hole structure on different planes with constant spacing and hierarchical layers on the test piece is formed as the key feature structure for machine tool movement error identification. The size parameters of the test piece are scaled to meet the detection needs of numerical control machine tools of different sizes, and the relationship between the size parameters of the test piece remains unchanged.

[0006] The method identifies nine movement errors of XYZ axes of high-precision three-axis numerical control machine tool. The identified movement errors are used to predict machining errors to obtain compensation data for error compensation. The specific steps include:

[0007] 1) Obtaining test specimens: Using a computer, a three-dimensional model of the test specimen is created within the same space with given dimensional parameters; the three-dimensional model of the test specimen is imported into a CNC machine tool, and machining operations are performed to obtain the test specimen;

[0008] 2) For the test piece processed in step 1), measure and number the actual coordinate positions of the center points of the bottom surfaces of each feature circular hole in the array in the same coordinate system of the model;

[0009] 3) Identify the motion error of a high-precision three-axis CNC machine tool. The relationship between the motion error of a high-precision three-axis CNC machine tool and the geometric errors in the X, Y, and Z directions of a point P on the test piece is as follows:

[0010] E xp =δ X(z) +δ X(y) +δ X(x)

[0011] E yp =δ Y(z) +δ Y(y) +δ Y(x)

[0012] E zp =δ Z(y) +δ Z(z) +δ Z(x)

[0013] To identify the above nine motion errors, first list the actual coordinates and ideal coordinates of the center of the hole feature at the bottom of the hole in the test piece, and then subtract the ideal coordinates from the actual coordinates to obtain the geometric error.

[0014] The expressions for the geometric errors of a series of points on the test piece and the motion errors of the machine tool can be simplified as follows:

[0015] E xi =δ X(x)

[0016] E yi =δ Y(x)

[0017] E zi =δ Z(x)

[0018] i is the hole number, E xi E yi E zi For each point, the geometric error in the X, Y, and Z directions is identified. This step involves identifying the X-axis motion error. A series of E values ​​can be obtained for these points, which change with the x-coordinate. xi E yi E zi Fit E respectivelyxi Regarding x coordinate, E yi E yp Regarding x coordinate, E zi Regarding x coordinate, E X(x) , δ Y(x) , δ Z(x) ;

[0019] Similarly, identify positioning error and straightness error δ X(y) , δ Y(y) , δ Z(y) of Y axis; identify positioning error and straightness error δ X(z) , δ Y(z) , δ Z(z) of Z axis;

[0020] 4) Predict the geometric error of the workpiece in processing: after identifying the main nine motion errors of the high-precision CNC machine tool XYZ axis, according to the identified motion error, use the relationship between the geometric error of the workpiece and the motion error of the machine tool to predict the geometric error of the workpiece in processing; before prediction, first back-propagate the geometric error E xi ', E yi ' and E zi ' of the feature points on the test piece according to the identified motion error, and compare it with the geometric error E xi , E yi , E zi obtained by direct measurement and calculation, such as E xi ' and E xi of the 44 hole features on the test piece in order from i = 1 to i = 44, and connect them into broken lines respectively, observe the deviation between the two broken lines, take a constant K x , so that E xi + K x and E xi two broken lines are as close as possible, so as to obtain the residual K x ; similarly, obtain the residuals K y , K z , therefore, the formula for predicting the geometric error of a certain position k is:

[0021] E xk = δ X(z) + δ X(y) + δ X(x) + K x

[0022] E yk = δ Y(z) + δ Y(y) + δ Y(x) + K y

[0023] Ezk = delta Z(y) + delta Z(z) + delta Z(x) + K z

[0024] 5) After the above detection steps are completed, the geometric error of the high-precision three-axis numerical control machine tool at any position in the space of the machined sample is predicted, and when any machined part is machined in the space, the predicted geometric error is compensated.

[0025] Further, in step 1), first, a three-dimensional model of the detection sample is established using a three-dimensional modeling commercial software according to the given size parameters; the three-dimensional model is imported into the numerical control machine tool, the machining process is set, the path is automatically planned, the remaining settings required for machining are completed, and finally the machine tool machining program is generated; then the machining sample blank is clamped in the machine tool workbench, the preparation process of tool setting and calibration is completed, and the machining operation is performed to machine the machining sample blank into the detection sample; the machined detection sample is removed from the machine tool and transferred to the horizontal workbench of the three-coordinate measuring machine, and the actual positions of each required feature point are measured to prepare for the subsequent steps.

[0026] Further, in step 1), in order to meet the test requirements, more than three detection samples are machined and manufactured using the above steps.

[0027] Further, in step 5), the compensation method can be through various commonly used error compensation methods, including an error compensation table, listing the geometric error of the tool movement to each axis at each position to make a table and import it into the machine tool numerical control system, and the machine tool numerical control system compensates the geometric error by changing the tool feed distance according to the error compensation table.

[0028] The beneficial effects of the present application are that the present application proposes a new type of detection sample, through the geometric error on the detection sample which is easy to measure, the motion error which is difficult to directly measure on the high-precision three-axis numerical control machine tool can be obtained by calculation, and the geometric error at any position in the machining space can be predicted through the obtained motion error, which is beneficial to improve the work efficiency and improve the machining precision. The calculation process is reasonably simplified, which can effectively improve the detection efficiency. The present application uses different parts on a single material sample for detection, improves the utilization rate of the sample, the sample structure is simple, and the machine tool machining is convenient. The sample can adapt to different machine tool operating systems and can be applied to error detection of high-precision three-axis numerical control machine tools of different sizes. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 A schematic diagram of the detection sample of the method of the present application;

[0030] Figure 2 A front view of the detection sample of the method of the present application;

[0031] Figure 3This is a top view of the test specimen tested by the method of the present invention;

[0032] Figure 4 This is a diagram showing the feature numbers of the circular holes in the test specimen for the method of this invention;

[0033] Figure 5 This is a schematic diagram of the cross-section of the test specimen and the test points of the method of the present invention;

[0034] Figure 6 This is a schematic diagram of motion error in the method of the present invention;

[0035] Figure 7 This is a schematic diagram of the machine tool structure in the illustrative example of the method of the present invention;

[0036] Figure 8 A schematic diagram of the hole features used for X-axis motion error identification in the method of the present invention;

[0037] Figure 9 A schematic diagram of the hole features used for Y-axis motion error identification in the method of the present invention;

[0038] Figure 10 This is a schematic diagram of the hole features used for Z-axis motion error identification in the method of the present invention. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0040] First, the test specimen described in this invention is described, such as... Figure 1 As shown, the geometric structure of the test specimen includes a cuboid base, a stepped structure on the base, and circular feature cavities arranged in a specific pattern on the base and the stepped structure. Its specific geometric parameters are as follows: Figure 2 , Figure 3 As shown, the structure of cavities arranged in an array with constant spacing and layered at different heights on different planes on the test piece is a key feature structure for identifying machine tool motion errors. There are two sets of circular feature cavities along the X-axis and Y-axis directions on the cuboid base, respectively, to identify various motion errors along the X and Y axes. The stepped structure has four steps of different heights, including a top surface and three stepped planes of different heights distributed on each side. The feature cavities of different heights distributed on the steps are used to identify various motion errors along the Z-axis.

[0041] The present invention provides a method for detecting various motion errors of a three-axis CNC machine tool based on a test specimen, which specifically includes the following steps:

[0042] 1. First, the three-axis CNC machine tool to be tested needs to be used to process, such as...Figure 1 The test specimen shown is described below, along with detailed instructions for its fabrication:

[0043] 1.1 Determine the basic dimensional parameters of the test specimen based on the machining range of the three-axis CNC machine tool to be tested. To ensure the integrity of the specimen data, the maximum XYZ travel value of the CNC machine tool can be used as the contour dimension of the test specimen. Alternatively, to complete the test quickly, small-sized test specimens can be machined to test the machining accuracy of commonly used machining areas. Multiple small-sized test specimens can also be used to perform error detection in different machining areas, obtaining the machining accuracy of different machining areas and then extrapolating the overall machining accuracy.

[0044] 1.2 Based on the given dimensional parameters, create a 3D model of the test specimen using SolidWorks or any similar commercial 3D modeling software. The dimensional parameters of the test specimen are as follows: Figure 2 , 3 As shown, the various dimensional parameters can be scaled proportionally to suit the inspection needs of CNC machine tools of different sizes, and the method described in this invention is applicable to test pieces of different sizes;

[0045] 1.3 Import the model into the CNC machine tool, set the machining process, automatically plan the path, complete the remaining settings required for machining, and finally generate the machine tool machining program.

[0046] 1.4 Clamp the blank in the machine tool worktable, complete the preparation process such as tool setting and calibration, execute the machining operation, and process the blank into a test piece;

[0047] 1.5 Remove the machined test piece from the machine tool and transfer it to the horizontal worktable of the coordinate measuring machine. Measure the actual positions of each required feature point to prepare for subsequent steps.

[0048] 1.6 To meet the testing requirements, more than three test pieces can be manufactured using the above steps.

[0049] 2. The following section, with reference to the accompanying drawings, details the steps for identifying various errors in a three-axis CNC machine tool:

[0050] 2.1 First, for ease of expression, all hole features are numbered, such as... Figure 4 As shown, from H01 to H44, determine the center position of the bottom circle of the hole feature on the test piece, then establish a workpiece coordinate system, list the theoretical and actual coordinate values ​​of each point in the workpiece coordinate system, and calculate the deviation between the theoretical and actual coordinate values, which is considered the error of that point. Use hole numbers for differentiation, such as: Figure 5 It is a cross-section passing through hole H04. After obtaining the position of the center of the aforementioned hole, the center is named after the hole number, that is... Figure 5 For point H04 on the x-axis, calculate the error of point H04 in the x-direction and denote it as E using the subscript.X04 .

[0051] 2.2 The motion errors of each axis of the three-axis CNC machine tool are calculated below based on the measured error values ​​of each point in the X, Y, and Z directions. For the same test piece, the motion errors shown in Table 1 are determined at the moment the test piece is completed, but the errors in Table 1 cannot be directly measured. What can be measured on the test piece is the geometric error of a certain point in the X, Y, and Z directions, and the geometric error in each direction is the sum of the motion errors in Table 1. This invention provides expressions for the geometric errors of points at different locations in the X, Y, and Z directions. By linking the measurable geometric error in a certain direction with the motion errors of each axis that are difficult to measure directly, the motion errors of each axis are then calculated.

[0052] 2.3 For a point P on the specimen, the relationship between the machine tool motion error and the geometric errors in the X, Y, and Z directions of point P can be listed (using... Figure 7 Taking the typical structure of a high-precision three-axis CNC machine tool as an example, the relationships between different structures of three-axis machine tools may differ in the signs of each term, but they are essentially the same and should not be construed as exceeding the scope of this invention.

[0053] E xp =y(ε γ(z) +ε γ(y) +ε γ(x) )+z(ε β(z) +ε β(y) +ε β(x) )+δ X(z) +δ X(y) +δ X(x)

[0054] E yp =x(ε γ(y) +ε γ(z) +ε γ(x) )+z(ε α(z) +ε α(y) +ε α(x) )+δ Y(z) +δ Y(y) +δ Y(x)

[0055] E zp =x(ε β(y) +ε β(z) +ε β(x) )+y(ε α(y) +ε α(z) +ε α(x) )+δ Z(y) +δ Z(z) +δ Z(x)

[0056] Because high-precision CNC machine tools require high precision during production and assembly, the perpendicularity between axes and the three angular errors (roll, pitch, and yaw angles) of each axis are very small. Compared with positioning and straightness errors, angular errors can be ignored. Furthermore, different angular errors may cancel each other out during actual machining. Therefore, to simplify the calculation process, positioning and straightness errors can be considered the main motion errors of high-precision three-axis CNC machine tools, and thus, positioning and straightness errors are calculated directly. The relationship between the machine tool motion error and the geometric errors in the X, Y, and Z directions of point P can be simplified as follows:

[0057] E xp =δ X(z) +δ X(y) +δ X(x)

[0058] E yp =δ Y(z) +δ Y(y) +δ Y(x)

[0059] E zp =δ Z(y) +δ Z(z) +δ Z(x)

[0060] Therefore, the 18 motion errors in Table 1 can be simplified to the 9 motion errors in Table 2 for identification, thereby improving detection efficiency.

[0061] Table 1 Motion Error of High-Precision Three-Axis CNC Machine Tool

[0062]

[0063] The motion errors explained here are illustrated using the X-axis as an example. When a high-precision three-axis CNC machine tool moves along the X-axis guide (the X-axis does not need to be defined in this method; CNC machine tools usually indicate their XYZ axis positions), the resulting six errors are as follows: Figure 6 As shown, these six errors correspond one-to-one with the X-axis errors in Table 1.

[0064] X-axis positioning error refers to the offset in the X-axis direction when the tool moves in the X-axis during machining. In calculation, X-axis positioning error is defined as a function related to the x-position, expressed as δ. X(x) ;

[0065] The straightness error of the X-axis in the Y direction refers to the offset of the tool in the Y direction when it moves in the X direction. In calculations, the straightness error of the X-axis in the Y direction is defined as a polynomial function related to the x-position, expressed as δ. Y(x) ;

[0066] The straightness error of the X-axis in the Z-direction refers to the offset of the tool in the Z-direction when it moves in the X-direction. In calculations, the straightness error of the X-axis in the Z-direction is defined as a polynomial function related to the x-position, expressed as δ. Z(x) ;

[0067] The roll angle error of the X-axis refers to the angle of rotation of the tool around the X-axis when it moves along the X-axis. In calculations, the yaw angle error of the X-axis is defined as a polynomial function related to the x-position, expressed as δ. α(x) ;

[0068] The pitch angle error of the X-axis refers to the angle between the tool and the horizontal plane XOY when the tool moves along the X-axis. In calculation, the pitch angle error of the X-axis is defined as a polynomial function related to the x-position, expressed as δ. β(x) ;

[0069] The X-axis yaw angle error refers to the angle between the tool and the vertical plane XOZ when the tool moves along the X-axis. In calculations, the X-axis yaw angle error is defined as a polynomial function related to the x-position, expressed as δ. γ(x) ;

[0070] The definitions of the other errors in Table 1 follow the same pattern.

[0071] Table 2. Motion errors of high-precision three-axis CNC machine tools identified in this invention.

[0072]

[0073] To identify the errors in Table 2, all or some of the hole features on the test piece need to be used. First, the actual and ideal coordinates of the center of the hole feature at the bottom of the hole need to be listed, and the geometric error is obtained by subtracting the ideal coordinates from the actual coordinates.

[0074] 2.4 Taking the three motion errors of the X-axis in Table 2 as an example, the process of identifying the three X-axis errors is described in detail. Figure 8 To identify the hole features within the square frame, one of the two sets of hole features within the square frame can be selected for calculation (holes H01, H21-H28, and H15 as one set, and holes H06-H14 and H20 as another set), or both sets of hole features can be used separately for identification and comparison. Taking the set of holes H06-H14 and H20 as an example, the identification process is detailed below. First, according to section 2.1, a workpiece coordinate system is defined on the sample. According to section 2.2, the geometric error of the bottom center of this series of hole features is obtained. Since the Y and Z coordinates of this series of points in the workpiece coordinate system are equal, the influence of the Y and Z axis motion errors can be temporarily ignored. The expression for the geometric error of this series of points and the machine tool motion error can be further simplified as follows:

[0075] E xi =δX(x)

[0076] E yi =δ Y(x)

[0077] E zi =δ Z(x)

[0078] i is the hole number, E xi E yi E zi This step identifies the geometric error in the X, Y, and Z directions for each point. The X-axis motion error is also identified; this series of points yields a series of E values ​​that change with the x-coordinate. xi E yi E zi Fit E respectively xi Regarding the x-coordinate, E yi E yp Regarding the x-coordinate, E zi A function of the x-coordinate, thus obtaining δ X(x) δ Y(x) and δ Z(x) .

[0079] 2.5 Similarly, using Figure 9 The internal hole features of the square frame can be used to identify the positioning error and straightness error δ along the Y-axis. X(y) δ Y(y) and δ Z(y) .

[0080] 2.6 For the identification of Z-axis positioning error and straightness error, use... Figure 10 Taking the hole features within the box, specifically a group of holes H4 and H33-H36, as an example, we obtain the E value as the z-coordinate changes. xi E yi E zi The subsequent steps are the same as in 2.4, which can be used to identify the positioning error and straightness error δ of the Z-axis. X(z) δ Y(z) and δ Z(z) .

[0081] 2.7 After identifying the nine main motion errors of the XYZ axes of a high-precision CNC machine tool, the geometric error of the workpiece during machining can be predicted using the relationship between the geometric error of the workpiece and the motion error of the machining machine, based on the identified motion errors. Before prediction, the geometric error E of the feature points on the test workpiece can be deduced from the identified motion errors. xi '、E yi 'and E zi ', compared with the geometric error E obtained by direct measurement and calculation xi E yi Ezi Compare them separately, such as listing the E values ​​of the 44 hole features on the specimen in order from i=1 to i=44. xi 'and E xi Connect the two lines to form a broken line, observe the deviation between the two broken lines, and take a constant K. x E xi '+K x and E xi The two broken lines are made as close as possible to obtain the residual K. x Similarly, the residual K is obtained. y K z Therefore, the formula for predicting the geometric error at a certain position k is:

[0082] E xk =δ X(z) +δ X(y) +δ X(x) +K x

[0083] E yk =δ Y(z) +δ Y(y) +δ Y(x) +K y

[0084] E zk =δ Z(y) +δ Z(z) +δ Z(x) +K z

[0085] 2.8 After completing the above testing steps, the geometric error of a high-precision CNC machine tool at any position within the space where the sample is being machined can be predicted. When machining any workpiece in this space, the predicted geometric error can be compensated. Compensation can be achieved through various common error compensation methods, such as an error compensation table. This table lists the geometric errors of the tool moving to each axis at each position and imports it into the machine tool's CNC system. The system then compensates for the geometric error by changing the tool feed distance based on the error compensation table.

[0086] 2.9 In summary, the nine main motion errors of the XYZ axes of a high-precision three-axis CNC machine tool (Table 2) can be identified through the method steps described in this invention. The identified motion errors can be used to predict machining errors to obtain compensation data and perform error compensation.

[0087] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for detecting and compensating motion errors in a three-axis CNC machine tool based on test specimens, characterized in that: A test piece for detecting motion errors in three-axis CNC machine tools is used. The geometric structure of the test piece includes a base, a stepped structure on the base, and circular cavity structures arranged on the base and the stepped structure. These cavity structures, arranged in an array with constant spacing and layered heights on different planes, serve as key feature structures for identifying machine tool motion errors. The various dimensional parameters of the test piece are scaled proportionally to suit the testing needs of CNC machine tools of different sizes, ensuring that the relationships between the various dimensions of the test piece remain unchanged. This method identifies nine motion errors along the XYZ axes of a high-precision three-axis CNC machine tool. The identified motion errors are used to predict machining errors to obtain compensation data for error compensation. The specific steps include: 1) Obtaining test specimens: Using a computer, a three-dimensional model of the test specimen is created within the same space with given dimensional parameters; the three-dimensional model of the test specimen is imported into a CNC machine tool, and machining operations are performed to obtain the test specimen; 2) For the test piece processed in step 1), measure and number the actual coordinate positions of the center points of the bottom surfaces of each feature circular hole in the array in the same coordinate system of the model; 3) Identify the motion error of a high-precision three-axis CNC machine tool. The relationship between the motion error of a high-precision three-axis CNC machine tool and the geometric errors in the X, Y, and Z directions of a point P on the test piece is as follows: E xp =d X(z) +d X(y) +d X(x) E yp =d Y(z) +d Y(y) +d Y(x) E zp =d Z(y) +d Z(z) +d Z(x) To identify the above nine motion errors, first list the actual coordinates and ideal coordinates of the center of the hole feature at the bottom of the hole in the test piece, and then subtract the ideal coordinates from the actual coordinates to obtain the geometric error. The expressions for the geometric errors of a series of points on the test piece and the motion errors of the machine tool can be simplified as follows: E xi =d X(x) E yi =d Y(x) E zi =d Z(x) i is the hole number, E xi E yi E zi For each point, the geometric error in the X, Y, and Z directions is identified. This step involves identifying the X-axis motion error. A series of E values ​​can be obtained for these points, which change with the x-coordinate. xi E yi E zi Fit E respectively xi Regarding the x-coordinate, E yi E yp Regarding the x-coordinate, E zi A function of the x-coordinate, thus obtaining δ X(x) δ Y(x) and δ Z(x) ; Similarly, identify the positioning error and straightness error δ of the Y-axis. X(y) δ Y(y) and δ Z(y) Identify the positioning error and straightness error δ of the Z-axis. X(z) δ Y(z) and δ Z(z) ; 4) Predicting the geometric errors of the workpiece during machining: After identifying the nine main motion errors of the XYZ axes of a high-precision CNC machine tool, the geometric errors of the workpiece during machining are predicted using the relationship between the geometric errors of the workpiece and the motion errors of the machining machine, based on the identified motion errors. Before prediction, the geometric errors E of the feature points on the test workpiece are deduced from the identified motion errors. xi '、E yi 'and E zi ', compared with the geometric error E obtained by direct measurement and calculation xi E yi E zi Compare them separately, such as listing the E values ​​of the 44 hole features on the specimen in order from i=1 to i=44. xi 'and E xi Connect the two lines to form a broken line, observe the deviation between the two broken lines, and take a constant K. x E xi '+K x and E xi The two broken lines are made as close as possible to obtain the residual K. x Similarly, the residual K is obtained. y K z Therefore, the formula for predicting the geometric error at a certain position k is: E xk =d X(z) +d X(y) +d X(x) +K x E yk =d Y(z) +d Y(y) +d Y(x) +K y E zk =d Z(y) +d Z(z) +d Z(x) +K z 5) After completing the above testing steps, predict the geometric error of the high-precision three-axis CNC machine tool at any position in the space where the sample is being processed. When processing any workpiece in this space, the predicted geometric error can be compensated.

2. The method for motion error detection and compensation of a three-axis CNC machine tool based on a test specimen as described in claim 1, characterized in that: In step 1), firstly, a 3D model of the test piece is created using commercial 3D modeling software based on the given dimensional parameters; the 3D model is imported into a CNC machine tool, the machining process is set, the path is automatically planned, and the remaining settings required for machining are completed, finally generating a machine tool machining program; then, the sample blank is clamped in the machine tool worktable, the tool setting and calibration preparation process is completed, the machining operation is performed, and the sample blank is machined into a test piece; the machined test piece is removed from the machine tool and transferred to the horizontal worktable of a coordinate measuring machine, and the actual positions of each required feature point are measured to prepare for subsequent steps.

3. The method for detecting and compensating motion errors of a three-axis CNC machine tool based on a test specimen as described in claim 2, characterized in that: In step 1), in order to meet the testing requirements, more than three test pieces are processed and manufactured using the above steps.

4. The method for detecting and compensating motion errors of a three-axis CNC machine tool based on a test specimen as described in claim 1, characterized in that: In step 5), the compensation method can be various commonly used error compensation methods, including an error compensation table. The table lists the geometric errors of the tool moving to each axis at each position and imports it into the machine tool CNC system. The machine tool CNC system compensates for the geometric errors by changing the tool feed distance according to the error compensation table.

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