Error calibration method of machine tool, numerical control machine tool and storage medium

Abstract

The application relates to a machine tool error calibration method, a numerical control machine tool and a storage medium. The method comprises the following steps: detecting a point on a first reference structure to obtain linear axis point data; determining linear axis errors of the machine tool according to the linear axis point data and theoretical data corresponding to the first reference structure; detecting a reference point on a second reference structure after a rotary shaft rotates to obtain rotary axis point data; and determining rotary axis errors of the machine tool according to the rotary axis point data and theoretical data corresponding to the rotary shaft. The method can reduce the calibration cost of the machine tool while ensuring the calibration accuracy.

Description

Technical Field

[0001] This application relates to the field of machine tool technology, and in particular to a machine tool error calibration method, a CNC machine tool, and a storage medium. Background Technology

[0002] Geometric error measurement and compensation for five-axis machine tools are effective means to ensure machining accuracy during long-term use. Traditional machine tool error calibration methods generally use equipment such as laser interferometers and ballbars for measurement, which can obtain high-precision errors, and error compensation can guarantee the accuracy of the machine tool. However, traditional methods suffer from high error calibration costs. Summary of the Invention

[0003] Therefore, it is necessary to provide a machine tool error calibration method, a CNC machine tool, and a storage medium to address the aforementioned technical problems, thereby reducing the cost of machine tool error calibration.

[0004] A machine tool error calibration method is applied to a machine tool, wherein a standard component is placed on the machine tool, the standard component including a first reference structure for calibrating linear axis errors and a second reference structure for calibrating rotary axis errors; the method includes:

[0005] Detect points on the first reference structure to obtain linear axonometric point data;

[0006] The linear axis error of the machine tool is determined based on the linear axis measurement point data and the theoretical data corresponding to the first reference structure.

[0007] After the rotation axis rotates, the reference point on the second reference structure is detected to obtain the rotation axis measurement point data;

[0008] The rotation axis error of the machine tool is determined based on the measurement data of the rotation axis and the theoretical data corresponding to the rotation axis.

[0009] A CNC machine tool includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of an embodiment of an error calibration method for each machine tool.

[0010] A computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of an embodiment of an error calibration method for various machine tools.

[0011] The aforementioned machine tool error calibration method, CNC machine tool, and storage medium, for the first reference structure, determine the measured straight line in the direction of the straight axis based on the measurement point data along the straight axis direction, determine the perpendicularity error of the machine tool based on the angle between the measured straight line and the corresponding theoretical axis, determine the straightness error based on the measurement point data and the corresponding measured straight line, and determine the positioning error based on the measurement point data and the theoretical data in the direction of the corresponding straight axis. Thus, the perpendicularity error, straightness error, and positioning error can be obtained through the first reference structure, that is, a large number of error values ​​can be obtained. The operation is simple and does not require high-precision equipment to participate in the machine tool calibration, reducing the machine tool calibration cost while ensuring calibration accuracy. Attached Figure Description

[0012] Figure 1 This is an application environment diagram of the machine tool error calibration method in one embodiment;

[0013] Figure 2 This is a flowchart illustrating the error calibration method for a machine tool in one embodiment;

[0014] Figure 3 This is a schematic diagram of the structure and parameters of a standard component in one embodiment;

[0015] Figure 4 This is a flowchart illustrating the error calibration method for a machine tool in one embodiment;

[0016] Figure 5 This is a schematic diagram of the measurement of the first and second measuring point data in one embodiment;

[0017] Figure 6 This is a schematic diagram illustrating the perpendicularity error between the first and second measured straight lines in one embodiment.

[0018] Figure 7 This is a schematic diagram illustrating the measurement of data from the third and fourth measuring points in one embodiment.

[0019] Figure 8 This is a schematic diagram illustrating the perpendicularity error between the third and fourth measured lines in one embodiment.

[0020] Figure 9 This is a schematic diagram of the measurement of the fifth and sixth measuring points in one embodiment;

[0021] Figure 10 This is a schematic diagram of the perpendicularity error between the fifth and sixth measured lines in one embodiment;

[0022] Figure 11 This is a schematic diagram of X-axis positioning error measurement in one embodiment;

[0023] Figure 12This is a schematic diagram illustrating the positional deviation of the measurement point caused by the clamping error angle of the standard part about the third linear axis in one embodiment.

[0024] Figure 13 This is a schematic diagram illustrating the positional deviation of the measurement point caused by the clamping error angle of the standard part around the second linear axis in one embodiment.

[0025] Figure 14 This is a schematic diagram of Y-axis positioning error measurement in one embodiment;

[0026] Figure 15 This is a schematic diagram of Z-axis positioning error measurement in one embodiment;

[0027] Figure 16 This is a schematic diagram illustrating the positional deviation of the measurement point caused by the clamping error angle of the standard part around the second linear axis in another embodiment.

[0028] Figure 17 This is a schematic diagram of C-axis calibration in one embodiment;

[0029] Figure 18 This is a schematic diagram of C-axis fitting and error decomposition in one embodiment;

[0030] Figure 19 This is a schematic diagram of A-axis calibration in one embodiment;

[0031] Figure 20 This is a flowchart illustrating the error calibration method for a machine tool in another embodiment;

[0032] Figure 21 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0033] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0035] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly. The connection can be a direct connection or an indirect connection.

[0036] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0037] It is understood that in the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., transmit electrical signals or data to each other. "Acquiring data" in the embodiments of this application may refer to acquiring data pre-stored in the machine tool, or it may include steps of determining / generating / processing data.

[0038] The terms "first," "second," etc., used in this application may be used to describe various data, but these data are not limited by these terms. These terms are only used to distinguish one data from another. For example, without departing from the scope of this application, a first linear axis may be referred to as a second linear axis, and similarly, a second linear axis may be referred to as a first linear axis. Both the first and second linear axes are linear axes, but they are not the same linear axis. It is understood that the first, second, and third linear axes are not the same; for example, the first linear axis may be the X-axis, the second linear axis may be the Y-axis, and the third linear axis may be the Z-axis; or the first linear axis may be the X-axis, the second linear axis may be the Z-axis, and the third linear axis may be the Y-axis; or the first linear axis may be the Y-axis, the second linear axis may be the X-axis, and the third linear axis may be the Z-axis, and so on, in any combination. In the embodiments of this application, the first linear axis is the X-axis, the second linear axis may be the Y-axis, and the third linear axis may be the Z-axis, as an example for illustration. Linear axes are axes used by machine tools during operation and have a certain degree of error before calibration. For example, the first linear axis, the second linear axis, and the third linear axis are all machine tool linear axes. Theoretical linear axes are linear axes that are theoretically perpendicular to each other, such as the theoretical X-axis, the theoretical Y-axis, and the theoretical Z-axis.

[0039] The machine tool error calibration method provided in this application can be applied to, for example... Figure 1 In the application environment. For example... Figure 1 The diagram shown illustrates the application environment of a machine tool error calibration method in one embodiment. Figure 1This includes a five-axis machine tool platform 110 and a standard part 120. The standard part 120 is located on the five-axis machine tool platform 110. Clean the worktable and the standard part to ensure the workspace is clean and unobstructed during measurement. Clamp the standard part onto the worktable, where the designed marking features (i.e., Figure 1 The white frame (marked with a fixture) ensures the approximate position of standard parts during installation, facilitating automation of the calibration process. It should be noted that the table level and X-axis accuracy should be maintained when the machine tool is zeroed; subsequent calibrations are based on this. Further, a high-precision probe is installed and calibrated to obtain the probe's length, circular runout, and pre-travel at a fixed probing speed. During actual probing, the actual measuring point = recorded point + probe calibration data; for ease of description, this is referred to as... The calibration value of the probe should be stated. The detection accuracy of the calibrated probe should be better than ±0.003mm.

[0040] like Figure 2 The diagram shown is a structural schematic of standard component 120 in one embodiment. Figure 2 A coordinate system is established with the top left corner as the origin. Standard part 120 includes a stepped structure 1, a rectangular toothed structure 2, a planar structure 3, and a spherical surface 4, and may also include a circular hole 5. The kick surface and tread surface of the stepped structure 1 are perpendicular to the top surface of the rectangular toothed structure 2. The stepped structure 1 is mainly used to calibrate the positioning error of the linear axis. The rectangular toothed structure 2 is also used to calibrate the positioning error of the linear axis. The planar structure is used to calibrate straightness error, perpendicularity error, etc. It can be understood that the planar structure is not limited to... Figure 2 In section 3, all surfaces of the structures in standard part 120 can be planes, such as stepped surfaces, stepped treads, rectangular tooth convex surfaces, rectangular tooth concave surfaces, etc. Sphere 4 can be a precision sphere used to calibrate the rotation axis error. Circular hole 5 is used to establish the machine tool's measurement coordinate system. Figure 2 The large circular hole in the middle serves to reduce the weight of the standard block. The static geometric errors of the linear and rotary axes of a horizontal five-axis dual-rotary table machine tool include 12 linear axis errors and 9 rotary axis errors. The geometric errors of a five-axis machine tool can be categorized into linear axis errors and rotary axis errors according to axis type. Linear axis errors include, but are not limited to, positioning errors, straightness errors, and perpendicularity errors; rotary axis errors include, but are not limited to, angular errors and axis position errors.

[0041] The dimensions and relevant feature surface parameters of a designed standard part are given below. For example... Figure 3 The diagram shown illustrates the structure and parameters of a standard component in one embodiment. The main feature surfaces of standard component 120 are: side surface A, top surface B, rectangular toothed convex surface C, and rectangular toothed concave surface D (D1…D2). i ), step riser E (E1, E2...E) i ), step tread F (F1, F2...F)i The flatness of the step should be better than 0.01, the perpendicularity of the step side E to the step top F should be better than 0.01, the tolerance of dimensions w, d, h is ±0.003mm, and the tolerance of the spherical radius is ±0.001mm.

[0042] One source of error in data obtained from in-machine measurements using standard parts is the error of the standard parts themselves. The relevant features of the designed stepped groove standard part are measured using a high-precision coordinate measuring machine or other high-precision measuring equipment. A standard part can be considered a workpiece that is absolutely flat, absolutely parallel, and absolutely perpendicular. For example... Figure 3 As shown, a measurement coordinate system is established with one corner of the standard part as the origin. The measurement parameters of a certain standard part that meets the requirements are shown in Table 1 below.

[0043] Table 1. Characteristic parameters obtained from coordinate measuring machine measurement of a certain standard part.

[0044] Flatness of surface B 0.005 Dimension d accuracy ±0.003 Flatness of surface C 0.003 Dimensional accuracy h ±0.002 D side of the groove 0.002 Spherical accuracy ±0.001 Stepped surface E 0.004 Stepped surface F 0.004

[0045] Based on the above analysis, a standard part structure and error calibration scheme for measuring the geometric errors of an AC dual-rotary-table five-axis machine tool are proposed, belonging to the field of CNC machine tool machining accuracy. First, based on the geometric error terms of the five-axis machine tool to be calibrated, the geometric features of the standard part are determined, and a three-dimensional model of the standard part is designed. Then, based on the produced standard part, dimensional calibration is performed to obtain the actual dimensional data. Next, the standard part is installed on the five-axis machine tool to be measured, and a calibrated high-precision probe is used to detect the coordinate data according to the planned feature points. Finally, the geometric errors of the five-axis machine tool are identified according to the error calibration algorithm. This method improves the efficiency of machine tool geometric error calibration while ensuring accuracy.

[0046] In one embodiment, such as Figure 4 The diagram shown is a flowchart illustrating a machine tool error calibration method in one embodiment. Taking a machine tool as an example, the machine tool has standard parts placed on it. The standard parts include a first reference structure for calibrating linear axis errors and a second reference structure for calibrating rotary axis errors. The method includes the following steps:

[0047] Step 402: Detect points on the first reference structure to obtain linear axonometric point data.

[0048] Specifically, the first reference structure is associated with the linear axis and is composed of planes in different directions. The machine tool controls the probe to detect points on this first reference structure and obtain linear axis measurement point data.

[0049] Step 404: Determine the linear axis error of the machine tool based on the linear axis measurement point data and the theoretical data corresponding to the first reference structure.

[0050] The theoretical data corresponding to the first reference structure refers to the data obtained by measuring the standard part using high-precision measuring equipment, and this data is considered accurate. The theoretical data corresponding to the first reference structure includes, but is not limited to, the theoretical linear axis, step width, and perpendicularity.

[0051] Specifically, the machine tool determines the linear axis error based on the linear axis measurement point data and the corresponding theoretical data of the first reference structure. The linear axis error includes, but is not limited to, positioning error, straightness error, and perpendicularity error.

[0052] Step 406: After the rotation axis rotates, the reference point on the second reference structure is detected to obtain the rotation axis measurement point data.

[0053] The standard part is placed on the machine tool's operating table. When the machine tool's rotary axis rotates, the second reference structure of the standard part rotates accordingly. The second reference structure can be a spherical structure, a pyramidal structure, a conical structure, a circular hole structure, etc. The reference point indicates the location of the second reference structure. For example, the reference point for a spherical structure can be the center or the top of the sphere; the reference point for a pyramidal structure can be the vertex; the reference point for a conical structure can also be the vertex; and the reference point for a circular hole structure is the center, etc.

[0054] Specifically, after controlling the rotation of the rotating axis, the probe is controlled to detect reference points on the second reference structure, obtaining at least three rotating axis measuring points. It is understood that three points can define a circle, hence the need for at least three rotating axis measuring points.

[0055] Step 408: Determine the machine tool's rotary axis error based on the rotary axis measurement point data and the corresponding theoretical data of the rotary axis.

[0056] Theoretical data includes the theoretical position of the rotation axis center, and may also include the theoretical axis vector. Rotation axis errors include, but are not limited to, axis vector errors and axis position errors.

[0057] Specifically, the machine tool determines the rotation axis error based on the difference between the measurement data of the rotation axis and the corresponding theoretical data of the rotation axis.

[0058] In this embodiment, a standard component is placed on the machine tool. The standard component includes a first reference structure for calibrating the linear axis error and a second reference error for calibrating the rotary axis error. The linear axis error of the machine tool is determined by detecting points on the first structure and combining them with the theoretical data corresponding to the first reference structure. After the rotary axis rotates, reference points on the second reference structure are detected and combined with the theoretical data corresponding to the rotary axis to determine the rotary axis error of the machine tool. The linear axis error and rotary axis error of the machine tool can be measured using a single standard component. The obtained error types are numerous and the accuracy is high. The operation is simple and does not require high-precision equipment for machine tool calibration, reducing the cost of error calibration while ensuring calibration accuracy.

[0059] In one embodiment, determining the linear axis error of the machine tool based on linear axis measurement point data and theoretical data corresponding to the first reference structure includes:

[0060] For the first reference structure, the corresponding measured straight line is determined based on the measurement point data along the straight axis direction;

[0061] The perpendicularity error of the machine tool's linear axis is determined based on the angle between the measured straight line and the corresponding theoretical linear axis.

[0062] The straightness error of the machine tool is determined based on the measurement point data and the corresponding measured straight line.

[0063] The positioning error of the machine tool is determined based on the measurement point data and the theoretical data in the corresponding linear axis direction.

[0064] Specifically, the measurement point data along the linear axis direction is obtained by probing the first reference result along the linear axis direction. The measured straight line is generated based on the points probed by the machine tool, representing the actual linear axis of the machine tool, that is, the measurement axis on the measurement coordinate system; it can include the measured straight line of the X-axis, the measured straight line of the Y-axis, and the measured straight line of the Z-axis. It can be understood that the measured point data in the X-axis direction is fitted to generate the measured straight line of the X-axis, the measured point data in the Y-axis direction is fitted to generate the measured straight line of the Y-axis, and the measured point data in the Z-axis direction is fitted to generate the measured straight line of the Z-axis. Therefore, taking the linear axis direction as the X-axis direction as an example, the points on the first reference structure are probed along the X-axis direction to obtain the measurement point data along the X-axis direction, and the corresponding measured straight line of the X-axis is determined by fitting or interpolation.

[0065] The measured straight lines and their corresponding theoretical axes are used to determine the machine tool's perpendicularity. For example, the measured X-axis line corresponds to the theoretical X-axis, the measured Y-axis line corresponds to the theoretical Y-axis, and the measured Z-axis line corresponds to the theoretical Z-axis. The perpendicularity of the machine tool can be determined based on the angles between the measured straight lines and their corresponding theoretical axes. It can be understood that the clamping error angles can also be determined based on these angles. For example, the first angle between the measured Z-axis line and the theoretical Z-axis, and the second angle between the measured X-axis line and the theoretical X-axis, can be used to determine the perpendicularity between the measured X-axis and Z-axis lines, i.e., the perpendicularity between the X-axis and Z-axis of the machine tool's measurement coordinate system. It can be understood that, considering the standard part error and probe error to be very small and negligible, this second angle can be considered as the clamping error angle.

[0066] The straightness error of a machine tool's linear axes is used to represent the degree to which the machine tool's motion trajectory deviates from an ideal straight line. One commonly used method is the minimum containment area method, which uses two parallel straight lines to ensure that the actual trajectory is completely contained with minimal spacing. This embodiment uses this method for illustration. The machine tool can determine the straightness error based on the measured point data and the corresponding measured straight line. The straightness error can include X-axis straightness error, Y-axis straightness error, and Z-axis straightness error. For example, based on the X-axis measured point data and the measured straight line on the X-axis, the straightness error in the X-axis direction is determined. Furthermore, due to the offset of each axis in the other two axial directions in space, it can be further divided into X-axis Y-direction straightness error and X-axis Z-direction straightness error.

[0067] Positioning error represents the deviation between the commanded position and the actual position. It can be divided into deviations along the X, Y, and Z axes. The positioning error of the machine tool is determined based on X-axis measurement data and corresponding theoretical data along the X-axis direction. Furthermore, when measuring positioning error, axes other than the motion axes involved should remain stationary. However, since an indirect measurement scheme using standard parts is employed, the positioning error can be accurately identified through clamping error angles and perpendicularity data. Specifically, the positioning error of the machine tool can be determined based on measurement data, theoretical data along the corresponding linear axis direction, and the clamping error angle.

[0068] In this embodiment, the corresponding measured straight line is determined based on the measurement point data along the straight axis, and then the clamping error angle, perpendicularity error, and positioning error are determined. The measured data is small and the obtained error types are numerous and highly accurate. High-precision equipment is not required for machine tool calibration, which reduces the cost of error calibration while ensuring calibration accuracy.

[0069] In one embodiment, the first reference structure includes a planar structure, and the linear axis error includes a perpendicularity error;

[0070] Points on the first reference structure are probed to obtain linear axonometric point data, including:

[0071] The planes on the standard part are probed at intervals along the straight axis to obtain plane measurement point data;

[0072] Based on the linear axis measurement point data and the theoretical data corresponding to the first reference structure, the linear axis error of the machine tool is determined, including:

[0073] Determine the measured straight line based on the plane measurement point data;

[0074] The perpendicularity error of the machine tool is determined based on the angle between the measured straight line and the corresponding theoretical straight line axis.

[0075] The direction of the linear axis can be the first linear axis direction, the second linear axis direction, or the third linear axis direction, specifically the X-axis direction, the Y-axis direction, or the Z-axis direction.

[0076] Specifically, the machine tool controls the probe to probe the plane of the standard part at regular intervals along the linear axis, obtaining plane measurement point data. It is understood that the probe may not be aligned with the linear axis, but it is preferred to be aligned with the linear axis. The intervals can be the same or different, but the same intervals are preferred to ensure that the obtained measurement point data are evenly distributed axially, improving the representativeness of the data used in the straightness error calculation. For example, the machine tool controls the probe to probe the plane of the standard part at 1mm intervals along the X-axis, i.e., probe at X=1mm, probe at X=2mm, and so on, thereby obtaining plane measurement point data.

[0077] Planar measurement point data refers to the data recorded in the machine tool system. In the absence of error points, the planar measurement point data should lie on the same straight line. The machine tool determines the measured straight line based on the planar measurement point data through interpolation or fitting. The machine tool determines the perpendicularity error between two measured straight lines based on the angle between the measured straight line and the theoretical straight line axis, and the angle between another measured straight line and its corresponding theoretical straight line axis, and the difference between these angles. For example, the planar measurement point data includes X-axis, Y-axis, and Z-axis measurement point data, and the corresponding measured straight lines are the X-axis measured straight line, Y-axis measured straight line, and Z-axis measured straight line. The machine tool can determine the perpendicularity error between the X-axis and Y-axis measured straight lines, the perpendicularity error between the X-axis and Z-axis measured straight lines, and the perpendicularity error between the Y-axis and Z-axis measured straight lines based on the clamping error angles between the X-axis measured straight line and the theoretical X-axis, the Y-axis measured straight line and the theoretical Y-axis, and the Z-axis measured straight line and the theoretical Z-axis measured straight line.

[0078] In this embodiment, since the planes on the standard part are all considered to be flat and vertical planes, the planes of the standard part are probed at intervals along the linear axis to obtain plane measurement point data. Based on the clamping error angle between the plane measurement point data and the corresponding theoretical linear axis, the perpendicularity error of the machine tool can be determined. The operation is simple and the accuracy is high.

[0079] In one embodiment, probing the planes on a standard part at regular intervals along a linear axis to obtain plane measurement point data includes:

[0080] While keeping the coordinates unchanged in the direction of the third linear axis, the plane on the standard part is probed at intervals along the direction of the first linear axis to obtain the first measuring point data, and the plane on the standard part is probed at intervals along the direction of the second linear axis to obtain the second measuring point data.

[0081] While keeping the coordinates unchanged in the direction of the second linear axis, the plane on the standard part is probed at intervals along the direction of the first linear axis to obtain the third measuring point data, and the plane on the standard part is probed at intervals along the direction of the third linear axis to obtain the fourth measuring point data.

[0082] With the coordinates in the first linear axis direction unchanged, the plane on the standard part is probed at intervals along the second linear axis direction to obtain the fifth measuring point data, and the plane on the standard part is probed at intervals along the third linear axis direction to obtain the sixth measuring point data;

[0083] Determine the measured straight line based on the plane measurement point data, including:

[0084] The first measured straight line is determined based on the data from the first measurement point;

[0085] The second measured straight line is determined based on the data from the second measuring point.

[0086] The third measured straight line is determined based on the data from the third measuring point.

[0087] The fourth measured straight line is determined based on the data from the fourth measuring point;

[0088] The fifth measured straight line is determined based on the data from the fifth measuring point;

[0089] The sixth measured straight line is determined based on the data from the sixth measurement point;

[0090] The perpendicularity error of the machine tool is determined based on the angle between the measured straight line and the theoretical straight line axis, including:

[0091] Based on the clamping error angle between the first measured straight line and the first theoretical straight line axis, and the angle between the second measured straight line and the second theoretical straight line axis, determine the perpendicularity error between the first measured straight line and the second measured straight line.

[0092] Based on the clamping error angle between the third measured straight line and the first theoretical straight line axis, and the angle between the fourth measured straight line and the third theoretical straight line axis, determine the perpendicularity error between the third measured straight line and the fourth measured straight line.

[0093] Based on the angle between the fifth measured line and the third theoretical line axis, and the clamping error angle between the sixth measured line and the second theoretical line axis, determine the perpendicularity error between the fifth measured line and the sixth measured line.

[0094] The angle between the first measured straight line and the first theoretical straight line axis is called the clamping error angle. Similarly, the angle between the third measured straight line and the first theoretical straight line axis is also called the clamping error angle. Furthermore, the angle between the fifth measured straight line and the third theoretical straight line axis is also called the clamping error angle. It is understood that the value of the clamping error angle can be 0. Taking the X-axis in the machine tool topology as the reference axis, and the direction of the first straight line axis as the X-axis, the perpendicularity error between the X-axis and Y-axis can be determined based on the clamping error angle between the first measured straight line representing the X-axis and the theoretical X-axis, and the angle between the second measured straight line representing the Y-axis and the theoretical X-axis. The others are similar and will not be elaborated upon here.

[0095] The directions of the first, second, and third linear axes are different, and they are linear axes within the machine tool system, thus having a certain degree of error before calibration. The theoretical linear axis is considered the correct linear axis. The directions of the first, second, and third linear axes can be the X-axis, Y-axis, and Z-axis directions, respectively. In this embodiment, the first linear axis direction is taken as the X-axis, the second linear axis direction as the Y-axis, and the third linear axis direction as the Z-axis for illustration.

[0096] Specifically, with the coordinates in the third linear axis direction (Z-axis direction) unchanged, the plane on the standard part is probed at intervals along the first linear axis direction (X-axis direction) to obtain the first measuring point data {Data:Eyx}, and the plane on the standard part is probed at intervals along the second linear axis direction (Y-axis direction) to obtain the second measuring point data {Data:Exy}.

[0097] The first measured straight line Lyx is determined based on the first measurement point data {Data:Eyx}. The second measured straight line Lxy is determined based on the second measurement point data {Data:Exy}. The clamping error angle rotz between the first measured straight line Lyx and the first theoretical axis (theoretical X-axis), and the angle between the second measured straight line Lxy and the second theoretical axis (theoretical Y-axis) are used as the basis for the determination. Determine the perpendicularity error Sxy between the first measured straight line Lyx and the second measured straight line Lxy. For example... Figure 5The diagram illustrates the measurement of the first and second measurement point data in one embodiment. On the XOZ plane of the standard component, a suitable Z-direction height is selected based on the probe length. The probe is then moved along the X-axis to probe points on the standard component, acquiring the first measurement point data {Data:Eyx}. The measured {Data:Eyx} is then fitted using the least squares method to the first measured straight line: Lyx.

[0098] Similarly, on the stepped structure, a plane parallel to the YOZ direction is selected. Based on the probe length, a suitable height in the Z direction is chosen. A series of measurement points parallel to the Y direction are selected, and the change in the X coordinate is measured to determine the straightness in the Y direction, obtaining the second measurement point data {Data:Exy}. The measured {Data:Exy} is fitted using the least squares method to obtain the second measured straight line: Lxy.

[0099] like Figure 6 The diagram shown illustrates the perpendicularity error between the first and second measured straight lines in one embodiment. The formula for calculating the perpendicularity error between the first and second measured straight lines (representing the X-axis and Y-axis) is as follows:

[0100]

[0101] in, This is the angle between the Lxy axis and the Y-axis, since the X-axis is the reference axis. rotz represents the clamping error angle of the third linear axis (Z-axis). It should be noted that the perpendicularity calculated here is the error ECOY of the Y-axis around the C-axis (i.e., the Z-axis), while the error EAOY of the Y-axis around the A-axis (i.e., the X-axis) is negligible because its error is small and cannot be accurately identified through on-machine measurement of standard parts.

[0102] In this embodiment, the coordinates on the second linear axis (Y-axis direction) remain unchanged. The planes on the standard part are probed at intervals along the first linear axis (X-axis direction) to obtain third measurement point data {Data:Ezx}, and the planes on the standard part are probed at intervals along the third linear axis (Z-axis direction) to obtain fourth measurement point data {Data:Exz}. The third measured straight line Lzx is determined based on the third measurement point data {Data:Ezx}. The fourth measured straight line Lxz is determined based on the fourth measurement point data {Data:Exz}. The clamping error angle roty between the third measured straight line Lzx and the first theoretical linear axis (theoretical X-axis), and the angle between the fourth measured straight line Lxz and the third theoretical linear axis (theoretical Z-axis) are used as the basis for determining the measurement point data. Determine the perpendicularity error Sxz between the third measured straight line Lzx and the fourth measured straight line Lxz.

[0103] like Figure 7The diagram illustrates the measurement of the third and fourth measurement points in one embodiment. On the XOY plane of the standard part, a suitable Y coordinate is selected, and a series of measurement points parallel to the X direction are chosen. The height change of the Z coordinate is measured to determine the straightness in the X direction, thus obtaining the third measurement point data {Data:Ezx}. The measured {Data:Ezx} is then fitted to the third measured straight line Lzx using the least squares method.

[0104] Similarly, on the side of the standard block slot, a plane parallel to YOZ is selected. Based on the probe length, a suitable Y coordinate is chosen, and a series of measurement points parallel to the Z direction are selected. The change in the X coordinate is measured to determine the straightness in the Z direction, obtaining the fourth measurement point data {Data:Exz}. The measured {Data:Exz} is fitted using the least squares method to obtain the fourth measured straight line Lxz.

[0105] like Figure 8 The diagram shown illustrates the perpendicularity error between the third and fourth measured straight lines in one embodiment. The angle between Lzx, fitted from the third measurement point data {Data:Ezx}, and the theoretical X-axis reflects the angle of rotation of the standard block around the Y-axis when it is mounted on the gripper, i.e., the clamping error angle roty, also known as the clamping error angle of the standard part around the second straight axis. Therefore, the formula for calculating the perpendicularity error between the third and fourth measured straight lines (representing the X-axis and Z-axis) is as follows:

[0106]

[0107] in, It is the angle between the Lxz axis and the Z-axis. It should be noted that the perpendicularity calculated here is the error EBOZ of the Z-axis around the B-axis (i.e., the Y-axis).

[0108] In this embodiment, the coordinates on the first linear axis (X-axis direction) remain unchanged. The planes on the standard part are probed at intervals along the second linear axis (Y-axis direction) to obtain the fifth measurement point data {Data:Ezy}, and the planes on the standard part are probed at intervals along the third linear axis (Z-axis direction) to obtain the sixth measurement point data {Data:Eyz}. The fifth measured straight line Lzy is determined based on the fifth measurement point data {Data:Ezy}. The sixth measured straight line Lyz is determined based on the sixth measurement point data {Data:Eyz}. The perpendicularity error Syz between the fifth and sixth measured straight lines Lzy is determined based on the angle between the fifth measured straight line Lzy and the third theoretical linear axis (theoretical Z-axis), and the clamping error angle rotx between the sixth measured straight line Lyz and the second theoretical linear axis (theoretical Y-axis).

[0109] like Figure 9The diagram illustrates the measurement of the fifth and sixth measurement points in one embodiment. On a step surface parallel to XOY, a series of measurement points parallel to the Y-axis are selected at a suitable X-coordinate. The Z-coordinate variation is measured to determine the straightness in the Y-direction, obtaining the fifth measurement point data {Data:Ezy}. The measured {Data:Ezy} is then fitted using the least squares method to obtain the fifth measured straight line Lzy.

[0110] Similarly, on the plane with the Y-coordinate of 0 on the side of the standard part, a suitable X-coordinate is selected to determine a series of measurement points parallel to the Z-axis. The change in the Y-coordinate is measured to determine the straightness in the Z-direction, obtaining the data of the sixth measurement point {Data:Eyz}. The measured {Data:Eyz} is then fitted with the sixth measured straight line: Lyz using the least squares method.

[0111] like Figure 10 The diagram shown illustrates the perpendicularity error between the fifth and sixth measured straight lines in one embodiment. The angle rotx between the sixth measured straight line Lzy, fitted from the sixth measurement point data {data:Ezy}, and the second theoretical axis (theoretical Y-axis) reflects the angle of rotation of the standard block around the X-axis when it is mounted on the gripper, i.e., the clamping error angle rotx, also known as the clamping error angle of the standard part around the first straight axis.

[0112] The perpendicularity of the fifth and sixth measured lines (representing the Y-axis and Z-axis) is calculated as follows:

[0113]

[0114] in, This is the angle between the Lzy axis and the Z-axis. It should be noted that the perpendicularity calculated here is also the error E of the Z-axis around the A-axis. AOZ .

[0115] This yields three linear axis errors, including three perpendicularity terms: Sxy, Sxz, and Syz.

[0116] In this embodiment, the actual straightness deviation of the motion axis in space is described by two directions orthogonal to it. At the same time, the unavoidable installation error is indirectly identified and separated by fitting the straight line of the measured data to obtain the perpendicularity error between the three axes. This allows us to obtain the perpendicularity error of the machine tool in various directions, making the data more comprehensive and the calibration more accurate.

[0117] In one embodiment, the straightness error of the first linear axis of the machine tool in the direction of the second linear axis is determined based on the first measuring point data and the first measured straight line.

[0118] Based on the data from the second measuring point and the second measured straight line, determine the straightness error of the second linear axis of the machine tool in the direction of the first linear axis;

[0119] Based on the data from the third measuring point and the third measured straight line, determine the straightness error of the first linear axis of the machine tool in the direction of the third linear axis;

[0120] Based on the data from the fourth measuring point and the fourth measured straight line, determine the straightness error of the third linear axis of the machine tool in the direction of the first linear axis;

[0121] Based on the data from the fifth measuring point and the fifth measured straight line, determine the straightness error of the second linear axis of the machine tool in the direction of the third linear axis;

[0122] Based on the data from the sixth measuring point and the sixth measured straight line, determine the straightness error of the machine tool's third linear axis in the direction of the second linear axis.

[0123] Specifically, the naming convention for straightness is E[error direction][measurement point data axis]. Based on the first measurement point data and the first measured straight line, the straightness error of the machine tool's first linear axis in the direction of the second linear axis is determined:

[0124] The first measured straight line Lyx is obtained by fitting the first measurement point data {Data:Eyx} to a straight line using the least squares method. The first measurement point data {Data:Eyx} represents the change in Y-coordinate height to determine the straightness error in the X-axis direction. The formula for calculating the straightness error Eyx in the Y-axis direction is as follows:

[0125] Eyx| i ={Data:Eyx}|y i -Lyx|y i ,i=1,…

[0126] This indicates that the measurement data {Data:Eyx} takes the y-coordinate value of the i-th point. i The Y-coordinate value y of the i-th point of the fitted line Lyx i Subtract.

[0127] Based on the data from the second measuring point and the second measured straight line, determine the straightness error of the machine tool's second linear axis in the direction of the first linear axis:

[0128] The second measurement point data {Data:Exy} is fitted using the least squares method to obtain the straight line: Lxy. The formula for calculating the straightness error Exy of the Y-axis in the X-axis direction is as follows:

[0129] Exy| i ={Data:Exy}|x i -Lxy|x i ,i=1,…

[0130] This means that the X-coordinate value of the measured point data {Data:Exy} is taken as the i-th point and subtracted from the X-coordinate value of the i-th point of the fitted line Lxy.

[0131] Based on the data from the third measuring point and the third measured straight line, determine the straightness error of the machine tool's first linear axis in the direction of the third linear axis:

[0132] The third measurement point data {Data:Ezx} is fitted with the third measured straight line Lzx using the least squares method. The formula for calculating the straightness error Ezx of the X-axis in the Z-axis direction is as follows:

[0133] Ezx| i ={Data:Ezx}|z i -Lzx|z i ,i=1,…

[0134] This means that the Z-coordinate value of the measured point data {Data:Ezx} is taken as the value of the i-th point and subtracted from the Z-coordinate value of the i-th point of the fitted line Lzx.

[0135] Based on the data from the fourth measuring point and the fourth measured straight line, determine the straightness error of the machine tool's third linear axis in the direction of the first linear axis:

[0136] The fourth measured point data {Data:Exz} was fitted using the least squares method to obtain the fourth measured straight line Lxz. The formula for calculating the straightness Exz of the Z-axis in the X-axis direction is as follows:

[0137] Exz| i ={Data:Exz}|x i -Lxz|x i ,i=1,…

[0138] This means that the X-coordinate value of the measured point data {Data:Exz} is taken from the i-th point and subtracted from the X-coordinate value of the i-th point of the fitted line Lxz.

[0139] Based on the data from the fifth measuring point and the fifth measured straight line, determine the straightness error of the machine tool's second linear axis in the direction of the third linear axis:

[0140] The fifth measured point data {Data:Ezy} was fitted using the least squares method to obtain the fifth measured straight line Lzy. The formula for calculating the straightness Ezy of the Y-axis in the Z-axis direction is as follows:

[0141] Ezy| i ={Data:Ezy}|z i -Lzy|z i ,i=1,…

[0142] This means that the Z-coordinate value of the measured point data {Data:Ezy} is taken as the value of the i-th point and subtracted from the Z-coordinate value of the i-th point of the fitted line Lzy.

[0143] Based on the data from the sixth measuring point and the sixth measured straight line, determine the straightness error of the machine tool's third linear axis in the direction of the second linear axis:

[0144] The data from the sixth measurement point {Data:Eyz} was fitted to the sixth measured straight line Lyz using the least squares method. The formula for calculating the straightness Eyz of the Z-axis in the Y-axis direction is as follows:

[0145] Eyz| i ={Data:Eyz}|y i -Lyz|y i ,i=1,…

[0146] This means that the Y-coordinate value of the measured point data {Data:Eyz} is taken from the i-th point and subtracted from the Y-coordinate value of the i-th point of the fitted line Lyz.

[0147] In this embodiment, since the machine tool probes points on the actual object, only one direction of offset can be detected at a time. However, the offset on a coordinate axis may have two directions. Therefore, by obtaining the measurement point data through six probes and combining it with the obtained measured straight line, the straightness error of the three linear axes of the machine tool in the orthogonal direction can be fully detected, making the data more comprehensive and the calibration more accurate.

[0148] In one embodiment, the linear axis error includes a positioning error; the first reference structure includes a stepped structure; the stepped structure is used to locate the error in the two reference directions respectively;

[0149] Points on the first reference structure are probed to obtain linear axonometric point data, including:

[0150] The reference step surface of the probe step structure is moved a certain distance to obtain step measurement point data that characterizes the reference direction;

[0151] Based on the linear axis measurement point data and the theoretical data corresponding to the first reference structure, the linear axis error of the machine tool is determined, including:

[0152] The positioning error of the reference direction is determined based on the step measurement point data characterizing the reference direction and the theoretical data corresponding to the reference direction of the step surface.

[0153] Specifically, linear axis error includes positioning error. Positioning error is, for example, the offset error of the X-axis in the X-axis direction. It can be understood that a step structure contains two surfaces, the step riser and the step tread, which can be used to calibrate the positioning error in at least two reference directions. The step width d is the width of the step tread, and the step height h is the height of the step riser. Both the step width d and the step height h are standard values.

[0154] Let's take the Z-axis as a reference direction for the step surface, corresponding to the step height *h*, and the X-axis as the reference direction, corresponding to the step width *d*, as an example. When measuring the positioning error in the X-axis direction, the machine tool moves along the Z-axis at intervals (preferably *h*, *2h*, etc.), probing the step tread surface at these intervals to obtain step measurement point data characterizing the step width. Based on this step measurement point data, and the step width *d*, the machine tool can determine the positioning error in the X-axis direction.

[0155] Taking the X-axis as one reference direction for the step surface, corresponding to the step width *d*, and the Z-axis as another reference direction, corresponding to the step height *h*, as an example, when measuring the positioning error in the Z-axis direction, the step surface is probed at intervals along the X-axis (preferably d, 2d, etc.) to obtain step measurement point data representing the step height. The machine tool can then determine the positioning error in the Z-axis direction based on the step measurement point data representing the step height and the step height *h*.

[0156] In this embodiment, since the step structure has two surfaces that can be used for positioning, the reference step surface of the step structure can be probed every certain distance along one reference direction of the step surface to obtain step measurement point data representing the other reference direction. Then, based on the corresponding theoretical data, the positioning error can be determined. Thus, the positioning error of the machine tool can be easily measured using a standard part, reducing costs.

[0157] In one embodiment, the reference direction is the direction of the first linear axis;

[0158] Based on the step measurement point data characterizing the reference direction and the theoretical data corresponding to the reference direction of the step surface, the positioning error of the reference direction is determined, including:

[0159] Obtain the clamping error angle of the standard part around the third linear axis; the clamping error angle of the standard part around the third linear axis is determined based on the clamping error angle between the first measured linear axis and the first theoretical linear axis; the first measured linear axis is determined based on the data of the first measuring point; the data of the first measuring point is obtained by probing the plane of the standard part at intervals along the first linear axis while keeping the coordinates in the direction of the third linear axis unchanged.

[0160] Based on the coordinates on the second linear axis and the clamping error angle of the standard part around the third linear axis, determine the error correction value of the third linear axis;

[0161] Obtain the clamping error angle of the standard part around the second linear axis; the clamping error angle of the standard part around the second linear axis is determined based on the clamping error angle between the third measured linear axis and the first theoretical linear axis; the third measured linear axis is determined based on the data of the third measuring point; the data of the third measuring point is obtained by probing the plane on the standard part at intervals along the first linear axis while keeping the coordinates in the direction of the second linear axis unchanged.

[0162] The error correction value of the second linear axis is determined based on the step width, step height, and clamping error angle of the standard part around the second linear axis;

[0163] Obtain the perpendicularity between the third and fourth measured lines;

[0164] Based on the perpendicularity between the third and fourth measured lines and the theoretical data corresponding to the axis direction of the first line, determine the perpendicularity correction value;

[0165] The positioning error of the first linear axis direction is determined based on the error correction values ​​of the third linear axis, the second linear axis, the perpendicularity correction value, and the difference between the step measurement point data representing the direction of the first linear axis and the theoretical data corresponding to the direction of the first linear axis.

[0166] The clamping error angle of the standard part around the third linear axis is determined by the machine tool based on data.

[0167] Specifically, let's take the third linear axis direction as the Z-axis direction, the first linear axis direction as the X-axis direction, and the second linear axis direction as the Y-axis direction as an example. Figure 11 The diagram shown is a schematic of X-axis positioning error measurement in one embodiment. A schematic diagram of the detection path is shown on the right. The machine tool obtains the clamping error angle rotz of the standard part around the third linear axis, with a step width of d and a step height of h. Then, axes A and C are zeroed, and a suitable Y-coordinate y is selected. Exx (i.e., coordinates on the second linear axis), the probe moves at a height of h along the Z-axis each time, probing along the X-axis until it reaches the step riser, thus obtaining the step measurement point data {Data:X Exx The theoretical width of the steps is d, and the theoretical height is h. The theoretical data for the steps in the X direction as a measuring tool can be calculated: {Data:X} ideal}

[0168] Based on the straightness and perpendicularity measurement results, the clamping error angle rotz of the standard part around the third linear axis causes the standard part to deviate, resulting in errors in the theoretical data of the measuring instrument. For example... Figure 12The diagram illustrates the positional deviation of the measurement point caused by the clamping error angle of the standard part around the third linear axis in one embodiment. To eliminate the influence of the installation error rotz, the coordinates y on the second linear axis are used... Exx Determine the error correction value ΔX of the third linear axis by considering the clamping error angle rotz of the standard part around the third linear axis. rotz :

[0169]

[0170] Among them, the rotz angle is smaller, and the y Exx ≈y Exx / cos(rotz), measurement point set {Data:X Exx Since the Y-coordinates of the items are the same, the correction values ​​for this item are also the same.

[0171] In addition to the installation error rotz, the clamping error angle roty of the standard part around the second linear axis causes the step surface to tilt, affecting the actual spacing of the measuring tape. like Figure 13 The diagram illustrates the positional deviation of the measurement point caused by the clamping error angle of the standard part around the second linear axis in one embodiment. To eliminate the influence of the installation error roty, a correction value ΔX is determined based on the step width d, step height h, and the clamping error angle roty of the standard part around the second linear axis. roty for

[0172]

[0173] Besides installation errors, according to the perpendicularity measurement results, the perpendicularity Sxz between the third and fourth measured straight lines is not 0. Since the machine tool reference axis in this embodiment is the X-axis, the perpendicularity error is compensated by movement along the X-axis. Therefore, based on the perpendicularity Sxz between the third and fourth measured straight lines and the theoretical data corresponding to the first axis direction {Data:X ideal}| i Determine the verticality correction value ΔComp corresponding to measuring point i. Sxz | i for

[0174] ΔComp Sxz | i ={Data:X ideal}| i *tan(Sxz), i=1,…

[0175] Wherein, ΔComp Sxz | i The coordinate axis that represents the direction of the first axis.

[0176] In summary, based on the error correction value ΔX of the third linear axis...rotz Error correction value ΔX for the second linear axis roty *i, Verticality correction value ΔComp Sxz | i And the difference between the step measurement point data representing the direction of the first linear axis and the theoretical data corresponding to the direction of the first linear axis {Data:X Exx}| i -{Data:X ideal}| i The X-axis positioning error data was determined and calculated as follows:

[0177] E xx | i ={Data:X Exx}| i -{Data:X ideal}| i +ΔComp Sxz | i +ΔX rotz +ΔX roty *i, i = 1, ...

[0178] In this embodiment, since there is a clamping error angle relative to the theoretical linear axis when the standard part is clamped, the influence of the clamping error angle needs to be removed when calculating the positioning error. This includes the error correction value of the second linear axis, the error correction value of the third linear axis, the perpendicularity correction value, etc. Then, the positioning error of the machine tool is determined based on the step measurement point data and the corresponding theoretical data. This can accurately obtain the positioning error of the machine tool in the first linear axis direction, and the cost is low.

[0179] In one embodiment, the standard component includes a rectangular tooth structure; probing points on the first reference structure to obtain linear isometric point data includes:

[0180] Detect tooth feature points on a rectangular tooth structure to obtain tooth feature measurement point data;

[0181] Based on the linear axis measurement point data and the theoretical data corresponding to the first reference structure, the linear axis error of the machine tool is determined, including:

[0182] The positioning error of the machine tool's second linear axis direction is determined based on the tooth feature measurement point data and the tooth feature theoretical data.

[0183] Among them, tooth feature points refer to points that can represent the tooth width or groove width. The machine tool detects tooth feature points on a rectangular tooth structure to obtain tooth feature measurement point data {Data:Y}. Eyy}| i Based on the tooth feature measurement point data {Data:Y Eyy}| i And theoretical data {Data:Y ideal}|i The difference is used to determine the positioning error E in the direction of the second linear axis of the machine tool. yy | i E yy (i=1,..n) can form a positioning error interpolation table. The positioning error outside the corresponding detection point can be obtained by linear interpolation. The calculation formula can be expressed as:

[0184] E yy | p =(K p *E yy | i +E yy | i-1 ) / (1+K p )

[0185] Among them, K p =(y i -y p ) / (y p -y i-1 ).

[0186] Specifically, such as Figure 14 The diagram shown illustrates the measurement of Y-axis positioning error in one embodiment. The slot wall thickness and width are w1, and the theoretical data of the tooth features of the standard part are {Data:Y}. ideal}. Zero the A and C axes, select appropriate X and Z coordinates, choose detection feature points on the side of each groove in the Y direction, measure the Y coordinate of each measuring point, and obtain the tooth feature measuring point data {Data:Y Eyy During the measurement process, the X and Z coordinates of the detection point remained consistent, and the installation error was negligible. Therefore, the Y-axis positioning error can be calculated as follows:

[0187] E yy | i ={Data:Y Eyy}| i -{Data:Y ideal}| i ,i=1,…

[0188] In this embodiment, tooth feature points on the rectangular tooth structure are detected to obtain tooth feature measurement point data. Based on the tooth feature measurement point data and tooth feature theoretical data, the positioning error of the machine tool in the second direction can be accurately determined, and the cost is low.

[0189] In one embodiment, the reference direction of the stepped surface is the direction of the third linear axis;

[0190] Based on the step measurement point data characterizing the reference direction and the theoretical data corresponding to the reference direction of the step surface, the positioning error of the reference direction is determined, including:

[0191] Obtain the clamping error angle of the standard part around the second linear axis; the clamping error angle of the standard part around the second linear axis is determined based on the clamping error angle between the third measured linear axis and the first theoretical linear axis; the third measured linear axis is determined based on the data of the third measuring point; the data of the third measuring point is obtained by probing the plane on the standard part at intervals along the first linear axis while keeping the coordinates in the direction of the second linear axis unchanged.

[0192] The error correction value of the second linear axis is determined based on the step width, step height, and clamping error angle of the standard part around the second linear axis;

[0193] The positioning error of the third linear axis direction is determined based on the error of the second linear axis and the difference between the step measurement point data characterizing the direction of the third linear axis and the theoretical data corresponding to the direction of the third linear axis.

[0194] The clamping error angle of the standard part around the second linear axis is obtained after the machine tool is calibrated.

[0195] Specifically, such as Figure 15 The diagram shown illustrates the measurement of Z-axis positioning error in one embodiment. The theoretical width of the step is d, and the theoretical height is h. Therefore, axes A and C are set to zero, and a suitable Y-coordinate is selected. Exx The probe moves a certain distance along the X-axis with a width of d each time, and probes until it reaches the step surface, thus obtaining the measurement point data {Data:Z} on the third linear axis. Ezz Due to the clamping error angle (roty) of the standard part about the second linear axis, the stepped surface of the standard part is not parallel to the established coordinate system datum plane. For example... Figure 16 The diagram illustrates the positional deviation of the measurement point caused by the clamping error angle of the standard part around the second linear axis in another embodiment. The theoretical dimensions of the measuring scale change during actual measurement due to the positioning error. Specifically, the error correction value ΔZ of the second linear axis is determined based on the step width d, step height h, and the clamping error angle roty of the standard part around the second linear axis. roty for

[0196]

[0197] In summary, based on the second linear axis error ΔZ roty *i, and the step measurement point data representing the direction of the third linear axis {Data:Z Ezz}| i The theoretical data corresponding to the direction of the third linear axis {Data:Z ideal}| i The difference between them, the Z-axis positioning error can be calculated as:

[0198] Ezz| i ={Data:Z Ezz}| i-{Data:Z ideal}| i +ΔZ roty *i, i = 1, ...

[0199] Among them, the error caused by the clamping error angle rotz of the standard part around the third linear axis is very small and can be ignored.

[0200] In this embodiment, since the machine tool has a clamping error angle, the influence of the clamping error angle needs to be removed when calculating the positioning error. The error correction value of the second linear axis is included. Then, the positioning error of the machine tool is determined based on the step measurement point data and the corresponding theoretical data. This can accurately obtain the positioning error of the machine tool in the first linear axis direction, and the cost is low.

[0201] In one embodiment, the second reference structure includes a spherical structure;

[0202] After the rotation axis rotates, the reference point on the second reference structure is probed to obtain the rotation axis measurement point data, including:

[0203] Control the rotation axis to rotate at least twice, and after rotation, detect the reference point of the spherical structure to obtain at least three sphere positions;

[0204] Based on the rotary axis measuring point data and the corresponding theoretical data of the rotary axis, the rotary axis error of the machine tool is determined, including:

[0205] The center position of the measured circular surface is determined by at least three sphere positions, and the measured axis position is obtained.

[0206] The axis position error of the machine tool's rotating axis is determined based on the measured axis position and the theoretical axis position.

[0207] The machine tool is a five-axis CNC machine tool. The second reference structure includes a spherical structure. This spherical structure can be a sphere, a hemisphere, or other spherical surfaces. The machine tool's rotation axes include the A-axis and the C-axis, and the errors of the A-axis and C-axis can be calibrated according to the method described in this embodiment. The reference point of the spherical structure can be the center of the sphere or the highest point of the sphere, preferably the center of the sphere. Similarly, the position of the sphere can be the center of the sphere or the highest point of the sphere.

[0208] Specifically, the machine tool can detect a reference point once in the initial state, and then acquire the reference point once for each subsequent rotation, obtaining at least three ball positions. Based on these at least three ball positions, the center position of the measured circular surface PL is determined, and this center position is the measured axis center position. The machine tool can then determine the axis center position error of its rotation axis based on the difference between the measured axis center position and the theoretical axis center position.

[0209] Furthermore, taking the rotation axis as the C-axis as an example, the machine tool determines the surface normal vector of the measured circular surface PL1. This allows us to determine the angle AOC between the surface normal vector and the theoretical X-axis, as well as the surface normal vector. The angle BOC between the theoretical Y-axis and the Y-axis.

[0210] like Figure 17 The diagram shown illustrates the C-axis calibration in one embodiment. The spherical surface of the standard part can be used to measure the rotation axis of the C-axis. The measurement steps are as follows:

[0211] ① Clean the worktable, clamp the standard part on the worktable, ensure that the spherical surface on the standard part is smooth, and set the X, Y, Z, A, and C axes to zero.

[0212] ② Calibrate the probe and obtain the probe error value.

[0213] ③ Use a probe to measure the sphere. Keep the detection speed constant and measure five points on the top of the sphere and the equator of the sphere in sequence. Combine the probe error and use the least squares method to fit the center of the circle as the data of measurement point 1.

[0214] ④ Repeat step ③ and measure points 2 to 4 corresponding to C-axis angles of 90°, 180°, and 270° in sequence.

[0215] ⑤ Fit plane PL1 based on points 1-4, and then fit as shown in the figure. Figure 17 Circle O1 on the midplane PL1.

[0216] ⑥ The position of the C-axis is calculated, where the Z-coordinate is not of any reference value.

[0217]

[0218] ⑦ For example Figure 18 The diagram shown illustrates the C-axis fitting and error decomposition in one embodiment. The C-axis vector is equal to the PL1 surface normal vector. AOC is the angle between the measured axis vector and the theoretical axis vector in the X direction, and BOC is the angle between the measured axis vector and the theoretical axis vector in the Y direction.

[0219] Optionally, taking the rotation axis as axis A as an example, the machine tool determines the surface normal vector of the measured circular surface PL2. This allows us to determine the surface normal vector. The angle between the plane and the theoretical Y-axis, and the surface normal vector. The angle between the theoretical Z-axis and the Z-axis.

[0220] The A-axis measurement principle is similar to that of the C-axis. However, because the spherical surface of the standard sphere rotates with the A-axis, it becomes difficult to accurately measure different latitude and longitude feature points on the sphere. Therefore, the measurement range for the A-axis error is set to -15° to 15°. Optionally, by optimizing the installation method of the standard sphere and adding a spherical support, the measurement azimuth of the A-axis can be increased, not limited to -15° to 15°. The specific measurement steps are as follows:

[0221] ① Set the X, Y, Z, A, and C axes to zero and move them to A = -15°.

[0222] ② Use a probe to measure the sphere. Keep the detection speed constant and measure five points on the top of the sphere and the equator of the sphere in sequence. Combine the probe error and use the least squares method to fit the center of the circle as the data of measurement point 1.

[0223] ③ Repeat step ② and measure points 2 to 5 corresponding to A-axis values ​​of -7.5°, 0°, 7.5° and 15° in sequence.

[0224] ④ Fit plane PL2 based on points 1-4, and then fit circle O2 on plane PL2. For example... Figure 19 The figure shown is a schematic diagram of A-axis calibration in one embodiment.

[0225] ⑤ Calculate the position of axis A using the following formula:

[0226]

[0227] ⑥ The vector of axis A is equal to the normal vector of surface PL2. This allows us to determine the surface normal vector. The angle between the plane and the theoretical Y-axis, and the surface normal vector. The angle between the theoretical Z-axis and the Z-axis.

[0228] In this embodiment, the positions of multiple balls are obtained by rotating the rotating shaft, thereby determining the actual axis center position. The axis center position error of the machine tool's rotating shaft is determined based on the actual axis center position and the theoretical axis position. By determining the axis center position error of the machine tool's rotating shaft, linear axis calibration and rotating axis calibration can be achieved through a single standard part, reducing costs.

[0229] In one embodiment, the standard part further includes a circular hole structure; the method further includes:

[0230] Probe at least three points on the inner wall of the circular hole structure, and determine the position of the center point of the circular hole based on at least three points;

[0231] Establish the machine tool's measurement coordinate system based on the position of the center point of the circular hole and the machine tool's reference axis.

[0232] The machine tool's measurement coordinate system is the coordinate system within the machine tool system. The machine tool moves according to its own established coordinate system, such as moving along the X-axis. Before calibration, the measurement coordinate system has a certain degree of error. The machine tool's reference axis is set according to requirements and can be one of the X-axis, Y-axis, and Z-axis, with the X-axis being the preferred option.

[0233] Specifically, the machine tool detects at least three points on the inner wall of the circular hole structure. Based on these three points, a circle can be determined, and the position of the center point of the circular hole can be determined. This position of the circular hole point can be a three-dimensional coordinate. Then, based on the machine tool's reference axis, the machine tool's measurement coordinates can be established.

[0234] Optionally, the position of the center point of the circular hole represents the coordinate axes in two directions. Then, by detecting the position of the plane containing the circular hole and combining it with the position of the center point of the circular hole, the three-dimensional coordinate position of the center point in space can be used as the origin, or a corner such as the upper right corner can be selected as the origin of the machine tool based on the size of the circular hole and the size of the standard part.

[0235] For example, according to Figure 1 The standard parts and the markings on the clamping plate are roughly aligned after installation. The machine tool first probes four points in the X and Y directions of the circular hole to obtain the center point of the hole, then exits the hole and probes the origin of the z-axis; next, the upper right corner of the standard part is used as the coordinate origin according to the design dimensions of the circular hole; the probe points [x0, y0, z0] are corrected according to the probe calibration data, as follows... The measurement coordinate system is established by combining the machine tool's standard axis, such as the X-axis. The probe calibration data is the data of all points measured subsequently, with this value added to them.

[0236] In this embodiment, at least three points on the inner wall of the circular hole structure are detected, the position of the center point of the circular hole and the position of the plane on which the circular hole is located are determined based on the at least three points, and the position of the axis of the linear axis is determined based on the position of the center point of the circular hole and the position of the plane on which the circular hole is located. Combined with the machine tool reference axis, a measurement coordinate system that can be used in the machine tool internal system can be established.

[0237] In one embodiment, such as Figure 20 The diagram shown is a flowchart illustrating the error calibration method for a machine tool in another embodiment. Figure 20 The process includes the following steps:

[0238] S100: Probe installation and calibration.

[0239] Specifically, a high-precision probe is installed and calibrated to obtain the probe's length, circular runout, and pre-travel at a fixed detection speed. During actual detection, the actual measurement point = recorded point + probe calibration data. For ease of description, the probe calibration value is represented by φ_probe. The detection accuracy of the calibrated probe should be better than ±0.003mm.

[0240] S200: Standard parts installation and measurement coordinate system measurement.

[0241] Specifically, when the machine tool is zeroed, the level of the worktable and the accuracy of the X-axis should remain good, and subsequent calibrations will be performed based on this. Clean the worktable and standard parts to ensure that the workspace is clean and unobstructed during measurement. Clamp the standard parts on the worktable. The designed marking features, when matched with the markings on the fixture, ensure the approximate position of the standard parts during installation, facilitating the automation of the calibration process. By probing the circular hole structure on the standard parts and the Z-axis origin, and combining this with the machine tool's reference axis, the measurement coordinate system is established.

[0242] S300: Measurement of perpendicularity of XY axis, XZ axis, and YZ axis.

[0243] Specifically, the XY axis perpendicularity Sxy, XZ axis perpendicularity Sxz, and YZ axis perpendicularity Syz have been obtained above.

[0244] S400: X-axis Y-direction straightness measurement and compensation, X-axis Z-direction straightness measurement and compensation; Y-axis X-direction straightness measurement and compensation, Y-axis Z-direction straightness measurement and compensation; Z-axis X-direction straightness measurement and compensation, Z-axis Y-direction straightness measurement and compensation.

[0245] Specifically, the straightness of the X-axis in the Y direction (Eyx), the straightness of the X-axis in the Z direction (Ezx), the straightness of the Y-axis in the X direction (Exy), the straightness of the Y-axis in the Z direction (Ezy), the straightness of the Z-axis in the X direction (Exz), and the straightness of the Z-axis in the Y direction (Eyz) have been obtained above.

[0246] S500: Measurement of positioning errors of X, Y, and Z axes and calculation of linear axis error compensation data.

[0247] Specifically, the X-axis positioning error, Y-axis positioning error, and Z-axis positioning error have been obtained above. The machine tool can then perform compensation calculations based on the obtained linear axis error data.

[0248] Step 600: Measurement of the position and vector direction of the A-axis and C-axis.

[0249] Specifically, it includes at least the C-axis position errors XOC and YOC, the angle AOC between the C-axis vector and the theoretical axis vector in the X direction, and the angle BOC between the C-axis vector and the theoretical axis vector in the Y direction; and the A-axis position errors XOA and YOA, the angle AOA between the A-axis vector and the theoretical axis vector in the Y direction, and the angle BOA between the C-axis vector and the theoretical axis vector in the Z direction.

[0250] In this embodiment, the geometric errors of the five-axis machine tool can be divided into linear axis errors and rotary axis errors according to the axis type. Linear axis errors include positioning errors, straightness errors, perpendicularity errors, and angular errors. Rotary axis errors include positioning errors, straightness errors, angular errors, and assembly errors. Specifically, this includes the positioning error, straightness, and perpendicularity of the linear axes, and the position and angular errors of the A and C axes.

[0251] The positioning error of a linear axis can be calibrated by designing a workpiece with a stepped shape. The probe obtains the interval of each step through collision detection and compares it with the actual interval to obtain the positioning error of the linear axis.

[0252] The straightness error of a linear axis can be calibrated by designing a plane parallel to a common reference plane. The probe detects a feature point of a straight line on this plane to obtain the levelness of the linear axis.

[0253] The perpendicularity error between axes can be solved by combining the horizontality errors of the two axes.

[0254] To address the error of the rotation axis, a standard spherical surface is designed for calibration. The spherical surface features rotate with the rotation axis, and the probe detects the center of the sphere at different positions. This allows for the fitting of the actual rotation plane, and by comparing it with the theoretical plane and the axis vector, the axis error of the rotation axis can be obtained.

[0255] In addition, to facilitate measurement, marking positions are designed for clamping and positioning when installing standard parts, and circular holes are designed to facilitate the establishment of a measurement coordinate system.

[0256] In this embodiment, a standard component can be used to calibrate the linear axis error and rotary axis error of the machine tool, which can improve the efficiency of machine tool geometric error calibration while ensuring accuracy.

[0257] In one embodiment, a machine tool error calibration method is applied to a machine tool, on which a standard part is placed. The standard part includes a first reference structure for calibrating linear axis errors and a second reference structure for calibrating rotary axis errors. The first reference structure includes a planar structure; the linear axis errors include perpendicularity errors and positioning errors; the first reference structure includes a stepped structure; the stepped structure is used for error positioning in two reference directions; the standard part includes a rectangular tooth structure. The method includes:

[0258] Step (a1): Detect at least three points on the inner wall of the circular hole structure, and determine the position of the center point of the circular hole based on the at least three points.

[0259] Step (a2): Establish the machine tool's measurement coordinate system based on the center point of the circular hole and the machine tool's reference axis; the measurement coordinate system is used for the control movement of the machine tool.

[0260] In step (a3), with the coordinates in the third linear axis direction unchanged, the plane on the standard part is probed at intervals along the first linear axis direction to obtain the first measuring point data, and the plane on the standard part is probed at intervals along the second linear axis direction to obtain the second measuring point data.

[0261] In step (a4), with the coordinates in the second linear axis direction unchanged, the plane on the standard part is probed at intervals along the first linear axis direction to obtain the third measuring point data, and the plane on the standard part is probed at intervals along the third linear axis direction to obtain the fourth measuring point data.

[0262] In step (a5), with the coordinates in the first linear axis direction unchanged, the plane on the standard part is probed at intervals along the second linear axis direction to obtain the fifth measuring point data, and the plane on the standard part is probed at intervals along the third linear axis direction to obtain the sixth measuring point data.

[0263] Step (a6): Determine the first measured straight line based on the data from the first measuring point.

[0264] Step (a7): Determine the second measured straight line based on the data from the second measuring point.

[0265] Step (a8): Determine the third measured straight line based on the data from the third measuring point.

[0266] Step (a9): Determine the fourth measured straight line based on the data from the fourth measuring point.

[0267] Step (a10): Determine the fifth measured straight line based on the data from the fifth measuring point.

[0268] Step (a11): Determine the sixth measured straight line based on the data from the sixth measuring point.

[0269] Step (a12): Determine the perpendicularity error between the first measured straight line and the second measured straight line based on the clamping error angle between the first measured straight line and the first theoretical straight line axis, and the angle between the second measured straight line and the second theoretical straight line axis.

[0270] Step (a13): Determine the perpendicularity error between the third measured line and the fourth measured line based on the clamping error angle between the third measured line and the first theoretical line axis, and the angle between the fourth measured line and the third theoretical line axis.

[0271] Step (a14): Determine the perpendicularity error between the fifth measured line and the sixth measured line based on the angle between the fifth measured line and the third theoretical line axis, and the clamping error angle between the sixth measured line and the second theoretical line axis.

[0272] Step (a15): Based on the data from the first measuring point and the first measured straight line, determine the straightness error of the first linear axis of the machine tool in the direction of the second linear axis.

[0273] Step (a16): Based on the data from the second measuring point and the second measured straight line, determine the straightness error of the second linear axis of the machine tool in the direction of the first linear axis.

[0274] Step (a17): Based on the data from the third measuring point and the third measured straight line, determine the straightness error of the first linear axis of the machine tool in the direction of the third linear axis.

[0275] Step (a18): Based on the data from the fourth measuring point and the fourth measured straight line, determine the straightness error of the third linear axis of the machine tool in the direction of the first linear axis.

[0276] Step (a19): Based on the data from the fifth measuring point and the fifth measured straight line, determine the straightness error of the second linear axis of the machine tool in the direction of the third linear axis.

[0277] Step (a20): Based on the data from the sixth measuring point and the sixth measured straight line, determine the straightness error of the third linear axis of the machine tool in the direction of the second linear axis.

[0278] In step (a21), the reference step surface of the probe step structure is moved a certain distance at each step to obtain step measurement point data that characterizes the direction of the first straight axis.

[0279] Step (a22) involves obtaining the clamping error angle of the standard part around the third linear axis. The clamping error angle of the standard part around the third linear axis is determined based on the clamping error angle between the first measured linear axis and the first theoretical linear axis.

[0280] Step (a23): Determine the error correction value of the third linear axis based on the coordinates on the second linear axis and the clamping error angle of the standard part around the third linear axis.

[0281] Step (a24) involves obtaining the clamping error angle of the standard part around the second linear axis. The clamping error angle of the standard part around the second linear axis is determined based on the clamping error angle between the third measured linear axis and the first theoretical linear axis.

[0282] Step (a25): Determine the error correction value of the second linear axis based on the step width, step height, and clamping error angle of the standard part around the second linear axis.

[0283] Step (a26) is to obtain the perpendicularity between the third and fourth measured lines.

[0284] Step (a27): Determine the perpendicularity correction value based on the perpendicularity between the third and fourth measured lines and the theoretical data corresponding to the axis direction of the first line.

[0285] Step (a28): Based on the error correction value of the third linear axis, the error correction value of the second linear axis, the perpendicularity correction value, and the difference between the step measurement point data representing the direction of the first linear axis and the theoretical data corresponding to the direction of the first linear axis, determine the positioning error of the first linear axis direction.

[0286] Step (a29) involves probing the tooth feature points on the rectangular tooth structure to obtain tooth feature measurement point data.

[0287] Step (a30) determines the positioning error of the second linear axis of the machine tool based on the tooth feature measurement point data and the tooth feature theoretical data.

[0288] In step (a31), the reference step surface of the probe step structure is moved a certain distance at each step to obtain step measurement point data that characterizes the direction of the third straight axis.

[0289] Step (a32) involves obtaining the clamping error angle of the standard part around the second linear axis. The clamping error angle of the standard part around the second linear axis is determined based on the clamping error angle between the third measured linear axis and the first theoretical linear axis.

[0290] Step (a33) determines the error correction value of the second linear axis based on the step width, step height, and clamping error angle of the standard part around the second linear axis.

[0291] Step (a34): Based on the error of the second linear axis and the difference between the step measurement point data characterizing the direction of the third linear axis and the theoretical data corresponding to the direction of the third linear axis, determine the positioning error of the direction of the third linear axis.

[0292] Step (a35): Control the rotation axis to rotate at least twice, and after rotation, detect the reference point of the spherical structure to obtain at least three spherical positions.

[0293] Step (a36): Determine the center position of the measured circular surface based on at least three sphere positions to obtain the measured axis position.

[0294] Step (a37): Determine the axis position error of the machine tool's rotating axis based on the measured axis position and the theoretical axis position.

[0295] In this embodiment, a standard component is placed on the machine tool. The standard component includes a first reference structure for calibrating the linear axis error and a second reference error for calibrating the rotary axis error. The linear axis error of the machine tool is determined by detecting points on the first structure and combining them with the theoretical data corresponding to the first reference structure. After the rotary axis rotates, reference points on the second reference structure are detected and combined with the theoretical data corresponding to the rotary axis to determine the rotary axis error of the machine tool. The linear axis error and rotary axis error of the machine tool can be measured using a single standard component. The obtained error types are numerous and the accuracy is high. High-precision equipment is not required for machine tool calibration, thus reducing the cost of error calibration.

[0296] It should be understood that, although the above Figure 4 and Figure 20 In the flowchart, the steps are shown sequentially according to the arrows, and the steps in steps (a1) to (a37) are shown sequentially according to the labels. However, these steps are not necessarily executed in the order indicated by the arrows or numbers. Unless explicitly stated herein, there is no strict order requirement for the execution of these steps; they can be executed in other orders. Furthermore, Figure 4 and Figure 20 At least some of the steps in the process may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but may be executed at different times. The execution order of these steps or stages is not necessarily sequential, but may be executed in turn or alternately with other steps or at least some of the steps or stages in other steps.

[0297] In one embodiment, a CNC machine tool is provided, the internal structure of which can be shown as follows: Figure 21 As shown, the computer device includes a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. When executed by the processor, the computer program implements a machine tool error calibration method. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0298] Those skilled in the art will understand that Figure 21 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0299] In one embodiment, a machine tool error calibration device is provided, which is used to implement the steps of the above-described method embodiments.

[0300] In one embodiment, a CNC machine tool is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the above-described method embodiments.

[0301] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method embodiments.

[0302] In one embodiment, a computer program product or computer program is provided, the computer program product or computer program including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, causing the computer device to perform the steps in the above method embodiments.

[0303] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes described in the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0304] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural changes made based on the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for calibrating the error of a machine tool, characterized in that, The method is applied to a machine tool, wherein a standard component is placed on the machine tool, the standard component including a first reference structure for calibrating linear axis errors and a second reference structure for calibrating rotary axis errors; the method includes: Detect points on the first reference structure to obtain linear axonometric point data; The linear axis error of the machine tool is determined based on the linear axis measurement point data and the theoretical data corresponding to the first reference structure. After the rotation axis rotates, the reference point on the second reference structure is detected to obtain the rotation axis measurement point data; the second reference structure includes a spherical structure; Based on the measured data of the rotating axis and the theoretical data corresponding to the rotating axis, the rotating axis error of the machine tool is determined; The step of determining the linear axis error of the machine tool based on the linear axis measurement point data and the theoretical data corresponding to the first reference structure includes: For the first reference structure, the corresponding measured straight line is determined based on the measurement point data along the straight axis direction; The perpendicularity error of the machine tool's straight axis is determined based on the angle between the measured straight line and the corresponding theoretical straight axis. The straightness error of the machine tool is determined based on the measured point data and the corresponding measured straight line. Based on the measured data and the theoretical data for the corresponding linear axis direction, the positioning error of the machine tool is determined; The step of detecting a reference point on the second reference structure after the rotation axis has rotated, and obtaining rotation axis measurement point data, includes: The rotation axis is controlled to rotate at least twice, and after rotation, the reference point of the spherical structure is detected to obtain at least three sphere positions; The step of determining the rotation axis error of the machine tool based on the rotation axis measuring point data and the corresponding theoretical data of the rotation axis includes: The center position of the measured circular surface is determined based on the positions of the at least three spheres, and the measured axis position is obtained. The axis position error of the rotating axis of the machine tool is determined based on the measured axis position and the theoretical axis position.

2. The method according to claim 1, characterized in that, The first reference structure includes a planar structure; The step of probing points on the first reference structure to obtain linear isometric point data includes: The plane on the standard part is probed at intervals along the straight axis to obtain plane measurement point data; The step of determining the linear axis error of the machine tool based on the linear axis measurement point data and the theoretical data corresponding to the first reference structure includes: The measured straight line is determined based on the plane measurement point data; The perpendicularity error of the machine tool is determined based on the angle between the measured straight line and the corresponding theoretical straight line axis.

3. The method according to claim 2, characterized in that, The step of probing the planes on the standard part at regular intervals along the linear axis to obtain plane measurement point data includes: While keeping the coordinates unchanged in the direction of the third linear axis, the plane on the standard part is probed at intervals along the direction of the first linear axis to obtain the first measuring point data, and the plane on the standard part is probed at intervals along the direction of the second linear axis to obtain the second measuring point data. While keeping the coordinates in the second linear axis direction unchanged, the plane on the standard part is probed at intervals along the first linear axis direction to obtain the third measuring point data, and the plane on the standard part is probed at intervals along the third linear axis direction to obtain the fourth measuring point data. While keeping the coordinates unchanged in the first linear axis direction, the plane on the standard part is probed at intervals along the second linear axis direction to obtain the fifth measuring point data, and the plane on the standard part is probed at intervals along the third linear axis direction to obtain the sixth measuring point data; The step of determining the measured straight line based on the plane measurement point data includes: Determine the first measured straight line based on the data from the first measuring point; Determine the second measured straight line based on the data from the second measuring point; The third measured straight line is determined based on the data from the third measuring point. The fourth measured straight line is determined based on the data from the fourth measuring point. The fifth measured straight line is determined based on the data from the fifth measuring point. The sixth measured straight line is determined based on the data from the sixth measuring point. The determination of the perpendicularity error of the machine tool based on the angle between the measured straight line and the corresponding theoretical straight axis includes: Based on the clamping error angle between the first measured straight line and the first theoretical straight line axis, and the angle between the second measured straight line and the second theoretical straight line axis, determine the perpendicularity error between the first measured straight line and the second measured straight line. Based on the clamping error angle between the third measured straight line and the first theoretical straight line axis, and the angle between the fourth measured straight line and the third theoretical straight line axis, the perpendicularity error between the third measured straight line and the fourth measured straight line is determined. The perpendicularity error between the fifth measured line and the sixth measured line is determined based on the angle between the fifth measured line and the third theoretical line axis, and the clamping error angle between the sixth measured line and the second theoretical line axis.

4. The method according to claim 3, characterized in that, The method further includes: Based on the first measuring point data and the first measured straight line, determine the straightness error of the first straight axis of the machine tool in the direction of the second straight axis; Based on the second measuring point data and the second measured straight line, determine the straightness error of the second straight axis of the machine tool in the direction of the first straight axis; Based on the data from the third measuring point and the third measured straight line, determine the straightness error of the first linear axis of the machine tool in the direction of the third linear axis; Based on the data from the fourth measuring point and the fourth measured straight line, determine the straightness error of the third linear axis of the machine tool in the direction of the first linear axis; Based on the data from the fifth measuring point and the fifth measured straight line, determine the straightness error of the second linear axis of the machine tool in the direction of the third linear axis; Based on the data from the sixth measuring point and the sixth measured straight line, the straightness error of the third straight axis of the machine tool in the direction of the second straight axis is determined.

5. The method according to claim 1, characterized in that, The linear axis error includes a positioning error; the first reference structure includes a stepped structure; the stepped structure is used to locate the error in the two reference directions respectively; The step of probing points on the first reference structure to obtain linear isometric point data includes: Each time the probe moves a certain distance, it detects the reference step surface of the step structure and obtains step measurement point data that characterizes the reference direction; The step of determining the linear axis error of the machine tool based on the linear axis measurement point data and the theoretical data corresponding to the first reference structure includes: The positioning error of the reference direction is determined based on the step measurement point data representing the reference direction and the theoretical data corresponding to the reference direction of the reference step surface.

6. The method according to claim 5, characterized in that, The reference direction is the direction of the first linear axis; The step of determining the positioning error of the reference direction based on the step measurement point data representing the reference direction and the theoretical data corresponding to the reference direction of the reference step surface includes: The clamping error angle of the standard part around the third linear axis is obtained; the clamping error angle of the standard part around the third linear axis is determined based on the clamping error angle between the first measured straight line and the first theoretical straight line; the first measured straight line is determined based on the first measuring point data; the first measuring point data is obtained by probing the plane of the standard part at intervals along the first straight line direction while keeping the coordinates in the direction of the third linear axis unchanged. The error correction value of the third linear axis is determined based on the coordinates on the second linear axis and the clamping error angle of the standard part around the third linear axis. The clamping error angle of the standard part around the second linear axis is obtained; the clamping error angle of the standard part around the second linear axis is determined based on the clamping error angle between the third measured linear axis and the first theoretical linear axis; the third measured linear axis is determined based on the third measuring point data; the third measuring point data is obtained by probing the plane on the standard part at intervals along the first linear axis while keeping the coordinates in the direction of the second linear axis unchanged. The error correction value of the second linear axis is determined based on the step width, step height, and the clamping error angle of the standard part around the second linear axis; Obtain the perpendicularity between the third and fourth measured lines; Based on the perpendicularity between the third and fourth measured straight lines and the theoretical data corresponding to the axis direction of the first straight line, the perpendicularity correction value is determined. The positioning error of the first straight axis direction is determined based on the error correction value of the third straight axis, the error correction value of the second straight axis, the perpendicularity correction value, and the difference between the step measurement point data representing the direction of the first straight axis and the theoretical data corresponding to the direction of the first straight axis.

7. The method according to claim 1, characterized in that, The standard component includes a rectangular tooth structure; The step of probing points on the first reference structure to obtain linear isometric point data includes: Detect tooth feature points on the rectangular tooth structure to obtain tooth feature measurement point data; The step of determining the linear axis error of the machine tool based on the linear axis measurement point data and the theoretical data corresponding to the first reference structure includes: The positioning error of the second linear axis of the machine tool is determined based on the tooth feature measurement point data and the tooth feature theoretical data.

8. The method according to claim 5, characterized in that, The reference direction of the reference step surface is the direction of the third linear axis; The step of determining the positioning error of the reference direction based on the step measurement point data representing the reference direction and the theoretical data corresponding to the reference direction of the reference step surface includes: The clamping error angle of the standard part around the second linear axis is obtained; the clamping error angle of the standard part around the second linear axis is determined based on the clamping error angle between the third measured linear axis and the first theoretical linear axis; the third measured linear axis is determined based on the third measuring point data; the third measuring point data is obtained by probing the plane on the standard part at intervals along the first linear axis while keeping the coordinates in the direction of the second linear axis unchanged. The error correction value of the second linear axis is determined based on the step width, step height, and the clamping error angle of the standard part around the second linear axis; The positioning error of the third linear axis direction is determined based on the error correction value of the second linear axis and the difference between the step measurement point data characterizing the direction of the third linear axis and the theoretical data corresponding to the direction of the third linear axis.

9. The method according to any one of claims 1 to 8, characterized in that, The standard component includes a circular hole structure; the method further includes: At least three points on the inner wall of the circular hole structure are detected, and the position of the center point of the circular hole is determined based on the at least three points. The measurement coordinate system of the machine tool is established based on the position of the center point of the circular hole and the reference axis of the machine tool.

10. A CNC machine tool, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 9.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 9.

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