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

Abstract

The invention relates to a machine tool error calibration method, a numerical control machine tool and a storage medium. The method comprises the following steps: detecting points on the first reference structure to obtain linear axis measurement point data; determining a linear axis error of the machine tool according to the linear axis measuring point data and theoretical data corresponding to the first reference structure; after the rotating shaft rotates, a reference point on the second reference structure is detected, and measuring point data of the rotating shaft are obtained; and determining the rotating shaft error of the machine tool according to the rotating shaft measuring point data and the theoretical data corresponding to the rotating shaft. By adopting the method, the calibration precision can be ensured while the calibration cost of the machine tool is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of machine tools, and in particular to an error calibration method for a machine tool, a numerically controlled machine tool, and a storage medium. Background Art

[0002] The geometric error measurement and compensation of a five-axis machine tool are effective means to ensure the machining accuracy during its long-term use. Traditional machine tool error calibration methods generally measure through devices such as laser interferometers and ball bar testers, which can obtain high-precision errors and ensure the accuracy of the machine tool after error compensation. However, the traditional method has the problem of high error calibration cost. Summary of the Invention

[0003] Based on this, in view of the above technical problems, it is necessary to provide an error calibration method for a machine tool, a numerically controlled machine tool, and a storage medium, which can reduce the cost of machine tool error calibration.

[0004] An error calibration method for a machine tool, applied to a machine tool on which a standard part is placed. The standard part includes a first reference structure for calibrating the error of a linear axis and a second reference structure for calibrating the error of a rotary axis. The method includes:

[0005] Detecting points on the first reference structure to obtain linear axis measurement point data;

[0006] Determining the linear axis error of the machine tool according to the linear axis measurement point data and the theoretical data corresponding to the first reference structure;

[0007] After the rotary axis rotates, detecting reference points on the second reference structure to obtain rotary axis measurement point data;

[0008] Determining the rotary axis error of the machine tool according to the rotary axis measurement point data and the theoretical data corresponding to the rotary axis.

[0009] A numerically controlled machine tool includes a memory and a processor. The memory stores a computer program. The processor, when executing the computer program, implements the steps of the error calibration method embodiments of each machine tool.

[0010] A computer-readable storage medium stores a computer program. When the computer program is executed by a processor, it implements the steps of the error calibration method embodiments of each machine tool.

[0011] The above-mentioned error calibration method for machine tools, CNC machine tools and storage media. For the first reference structure, the measured straight line in the straight axis direction is determined according to the measuring point data along the straight axis direction. The perpendicularity error of the machine tool is determined according to the included angle between the measured straight line and the corresponding theoretical axis. The straightness error is determined according to the measuring point data and the corresponding measured straight line. The positioning error is determined according to the measuring point data and the theoretical data in the corresponding straight axis direction. Then, through the first reference structure, the perpendicularity error, straightness error and positioning error can be obtained, that is, a large number of error values can be obtained. The operation is simple, and there is no need for high-precision equipment to participate in the machine tool calibration, which reduces the machine tool calibration cost and ensures the calibration accuracy at the same time. Brief Description of the Drawings

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

[0013] Figure 2 It is a schematic flowchart of the error calibration method for a machine tool in an embodiment;

[0014] Figure 3 It is a schematic diagram of the structures and parameters of a standard part in an embodiment;

[0015] Figure 4 It is a schematic flowchart of the error calibration method for a machine tool in an embodiment;

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

[0017] Figure 6 It is a schematic diagram of the perpendicularity error between the first measured straight line and the second measured straight line in an embodiment;

[0018] Figure 7 It is a measurement schematic diagram of the third measuring point data and the fourth measuring point data in an embodiment;

[0019] Figure 8 It is a schematic diagram of the perpendicularity error between the third measured straight line and the fourth measured straight line in an embodiment;

[0020] Figure 9 It is a measurement schematic diagram of the fifth measuring point data and the sixth measuring point data in an embodiment;

[0021] Figure 10 It is a schematic diagram of the perpendicularity error between the fifth measured straight line and the sixth measured straight line in an embodiment;

[0022] Figure 11 It is a measurement schematic diagram of the X-axis positioning error in an embodiment;

[0023] Figure 12Schematic diagram of the position deviation of the measurement point caused by the clamping error angle of the standard part around the third straight axis in an embodiment;

[0024] Figure 13 Schematic diagram of the position deviation of the measurement point caused by the clamping error angle of the standard part around the second straight axis in an embodiment;

[0025] Figure 14 Schematic diagram of the measurement of the Y-axis positioning error in an embodiment;

[0026] Figure 15 Schematic diagram of the measurement of the Z-axis positioning error in an embodiment;

[0027] Figure 16 Schematic diagram of the position deviation of the measurement point caused by the clamping error angle of the standard part around the second straight axis in another embodiment;

[0028] Figure 17 Schematic diagram of the calibration of the C-axis in an embodiment;

[0029] Figure 18 Schematic diagram of the C-axis axis fitting and error decomposition in an embodiment;

[0030] Figure 19 Schematic diagram of the calibration of the A-axis in an embodiment;

[0031] Figure 20 Schematic diagram of the process of the error calibration method of the machine tool in another embodiment;

[0032] Figure 21 Internal structure diagram of a computer device in an embodiment. Detailed implementation manners

[0033] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0034] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0035] It should be noted that all the directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly. The connection can be a direct connection or an indirect connection.

[0036] In addition, in this application, descriptions such as "first" and "second" are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0037] It can be understood that for "connection" in the following embodiments, if there is a transfer of electrical signals or data between the connected circuits, modules, units, etc., it should be understood as "electrical connection", "communication connection", etc. "Obtaining data" in the embodiments of this application can be obtaining data pre-stored in the machine tool, or can also include steps of determining / generating / processing data.

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

[0039] The error calibration method of the machine tool provided by this application can be applied to Figure 1 such an application environment. As Figure 1 shown, it is an application environment diagram of the error calibration method of the machine tool in an embodiment. Figure 1It 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 workbench and the standard part to ensure that the working space of the machine tool is clean and free of obstacles during measurement. Clamp the standard part on the workbench. The designed marking position feature (i.e., Figure 1 's white frame), when installed, matching the marking of the fixture can ensure the rough position of the standard part during installation, facilitating the automation of the calibration process. It should be noted that when the machine tool returns to zero, the accuracy of the workbench level and the X-axis should be kept good, and subsequent calibrations are carried out on this basis. Further, install a high-precision probe and calibrate the probe to obtain the length, circular runout of the probe, and the pre-travel of the measurement at a fixed detection speed. When actually detecting, the true measurement point = the recorded point + the probe calibration data. For the convenience of description, here is used to represent the probe calibration value. The detection accuracy of the calibrated probe should be better than ±0.003 mm.

[0040] As Figure 2 shown, it is a schematic structural diagram of the standard part 120 in an embodiment. Figure 2 A coordinate system is established with the upper left corner vertex as the origin. The standard part 120 includes a step structure 1, a rectangular tooth structure 2, a plane structure 3, a spherical surface 4, and may also include a round hole 5. The kicking surface and the stepping surface of the step structure 1 are both perpendicular to the top surface of the rectangular tooth structure 2. The step structure 1 is mainly used to calibrate the positioning error of the linear axis. The rectangular tooth structure 2 is also used to calibrate the positioning error of the linear axis. The plane structure is used to calibrate the straightness error, perpendicularity error, etc. It can be understood that the plane structure is not limited to Figure 2 in 3. The surfaces of each structure in the standard part 120 can all be planes, such as the step kicking surface, the step stepping surface, the rectangular tooth convex surface, the rectangular tooth concave surface, etc. The spherical surface 4 can be a precision sphere, which is used to calibrate the rotation axis error. The round hole 5 is used to establish the measurement coordinate system of the machine tool. Figure 2 The function of the large round hole structure in the middle is to reduce the weight of the standard block. The static geometric errors of the linear axis and the rotation axis of the horizontal five-axis double-turntable machine tool include 12 linear axis errors and 9 rotation axis errors. The geometric errors of the five-axis machine tool can be divided into linear axis errors and rotation axis errors according to the axis type. Among them, the linear axis errors include, but are not limited to, positioning errors, straightness errors, and perpendicularity errors; the rotation axis errors include, but are not limited to, angular errors and axis position errors.

[0041] The following gives the dimensions and related feature surface parameters of a designed standard part. As Figure 3 shown, it is a schematic diagram of the structures and parameters of the standard part in an embodiment. The main feature surfaces of the standard part 120 are the side surface A, the top surface B, the rectangular tooth convex surface C, the rectangular tooth concave surface D (D1... D i ), the step kicking surface E (E1, E2... E i ), the step stepping surface F (F1, F2... Fi ) The flatness should be better than 0.01, the perpendicularity between the side E of the step and the top surface F of the step should be better than 0.01, the tolerances of dimensions w, d, and h are ±0.003 mm, and the tolerance of the spherical radius is ±0.001 mm.

[0042] One of the error sources of the data obtained by in-machine measurement using standard parts is the error of the standard parts. Measure the relevant features of the designed stepped groove standard part through a high-precision coordinate measuring machine or other high-precision measuring equipment. The standard part can be considered as a workpiece with absolute flatness, absolute parallelism, and absolute perpendicularity. As Figure 3 shown, a measurement coordinate system is established with a corner of the standard part as the origin, and the measurement parameters of a certain standard part that meets the requirements are shown in Table 1 below.

[0043] Table 1 Characteristic parameters of a certain standard part measured by a coordinate measuring machine

[0044] Flatness of Surface A 0.007 Accuracy of Dimension w ±0.001 Flatness of Surface B 0.005 Accuracy of Dimension d ±0.003 Flatness of Surface C 0.003 Accuracy of Dimension h ±0.002 Side Surface D of Groove 0.002 Accuracy of Spherical Surface ±0.001 Step Surface E 0.004 Step Surface F 0.004

[0045] Based on the above analysis, a standard part structure and error calibration scheme for geometric error measurement of an AC double-turntable five-axis machine tool are proposed, belonging to the field of machining accuracy of numerically controlled machine tools. First, according to the geometric error items of the five-axis machine tool to be calibrated, the geometric features of the standard part are determined, and then the three-dimensional model of the standard part is designed. Then, according to the produced standard part, size calibration is first carried out to obtain the true size data. Next, the standard part is installed on the five-axis machine tool to be measured, and the calibrated high-precision probe is used to detect the coordinate data of the feature points according to the planned ones. Finally, according to the error calibration algorithm, the geometric errors of the five-axis machine tool are identified. In this way, the calibration efficiency of the machine tool geometric errors can be improved while ensuring the accuracy.

[0046] In one embodiment, as Figure 4 shown, it is a schematic flowchart of the error calibration method of the machine tool in one embodiment. Taking the application to the machine tool as an example, a standard part is placed on the machine tool, and the standard part includes a first reference structure for calibrating the linear axis error and a second reference structure for calibrating the rotary axis error; the method includes the following steps:

[0047] Step 402, detect the points on the first reference structure to obtain the linear axis measurement point data.

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

[0049] Step 404, determine the linear axis error of the machine tool according to the linear axis measurement point data and the theoretical data corresponding to the first reference structure.

[0050] Among them, the theoretical data corresponding to the first reference structure refers to the data obtained by measuring a standard part with a high-precision measuring device, and these data are considered accurate data. The theoretical data corresponding to the first reference structure includes but is not limited to a theoretical straight axis, step width, step width, perpendicularity, etc.

[0051] Specifically, the machine tool determines the straight axis error of the machine tool according to the straight axis measuring point data and the theoretical data of the corresponding first reference structure. Among them, the straight axis error includes but is not limited to positioning error, straightness error, and perpendicularity error.

[0052] Step 406: After the rotating axis rotates, detect the reference points on the second reference structure to obtain the rotating axis measuring point data.

[0053] Among them, the standard part is placed on the operating table of the machine tool. When the rotating axis of the machine tool rotates, the second reference structure of the standard part rotates accordingly. The second reference structure can be a spherical structure, a pyramid structure, a conical structure, a circular hole structure, etc. The reference point is the point representing the position of the second reference structure. For example, the reference point of the spherical position can be the center point or the top point, the reference point of the pyramid structure can be the vertex, the reference point of the conical structure can also be the vertex, and the reference point of the circular hole structure is the center point, etc.

[0054] Specifically, after controlling the rotating axis to rotate, control the probe to detect the reference points on the second reference structure to obtain at least three rotating axis measuring points. It can be understood that three points can determine a circle, so at least three rotating axis measuring points are taken.

[0055] Step 408: Determine the rotating axis error of the machine tool according to the rotating axis measuring point data and the theoretical data corresponding to the rotating axis.

[0056] Among them, the theoretical data includes the theoretical axis position of the rotating axis and may also include the theoretical axis vector. The rotating axis error includes but is not limited to axis vector error and axis position error.

[0057] Specifically, the machine tool determines the rotating axis error according to the difference between the rotating axis measuring point data and the theoretical data corresponding to the rotating 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 error of the linear axis and a second reference error for calibrating the error of the rotary axis. By detecting the points on the first structure and combining with the theoretical data corresponding to the first reference structure, the error of the linear axis of the machine tool is determined; after the rotary axis rotates, the reference points on the second reference structure are detected and combined with the theoretical data corresponding to the rotary axis to determine the error of the rotary axis of the machine tool. It is possible to measure the error of the linear axis and the error of the rotary axis of the machine tool through one standard component, with a large variety of obtained error types, high precision, simple operation, and no need to use high-precision equipment for calibrating the machine tool, reducing the cost of error calibration while ensuring the calibration accuracy.

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

[0060] For the first reference structure, the measured straight line corresponding thereto is determined according to the measured point data along the direction of the linear axis;

[0061] According to the included angle between the measured straight line and the corresponding theoretical linear axis, the perpendicularity error of the linear axis of the machine tool is determined;

[0062] According to the measured point data and the corresponding measured straight line, the straightness error of the machine tool is determined;

[0063] According to the measured point data and the theoretical data in the direction of the corresponding linear axis, the positioning error of the machine tool is determined.

[0064] Specifically, the measured point data along the direction of the linear axis is obtained by detecting the first reference result along the direction of the linear axis. The measured straight line is generated according to the points detected by the machine tool, representing the actual straight 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. Then, taking the direction of the linear axis as the X-axis direction as an example, the points on the first reference structure are detected along the X-axis direction to obtain the measured point data along the X-axis direction, and the measured straight line of the X axis corresponding to the measurement data is determined by fitting or interpolation.

[0065] The measured straight line and the corresponding theoretical straight line axis. For example, the measured straight line of the X-axis corresponds to the theoretical X-axis, the measured straight line of the Y-axis corresponds to the theoretical Y-axis, and the measured straight line of the Z-axis corresponds to the theoretical Z-axis. Then, according to the angle between the measured straight line and the corresponding theoretical axis, the perpendicularity of the machine tool can be determined. It can be understood that the clamping error angle can also be determined according to the measured straight line and the corresponding theoretical axis. For example, the first angle between the measured straight line of the Z-axis and the theoretical Z-axis, and the second angle between the measured straight line of the X-axis and the theoretical X-axis. According to the first angle and the second angle, the perpendicularity between the measured straight line of the X-axis and the measured straight line of the Z-axis can be determined, that is, the perpendicularity between the X-axis and the Z-axis of the machine tool measurement coordinate. It can be understood that, considering that the standard part error and the probe error are very small and can be ignored, this second angle can be regarded as the clamping error angle.

[0066] The straightness error of the machine tool linear axis is used to represent the degree to which the machine tool motion trajectory deviates from the ideal straight line. One of the commonly used methods is the minimum zone method. By two parallel straight lines, the actual trajectory is completely included and the distance between them is the smallest. This embodiment uses this method to illustrate. The machine tool can determine the straightness error according to the measured point data and the corresponding measured straight line. The straightness error can include the straightness error of the X-axis, the straightness error of the Y-axis, and the straightness error of the Z-axis. For example, according to the measured point data of the X-axis and the measured straight line of the X-axis, the straightness error in the X-axis direction is determined. Further, since each axis corresponds to the offset in the directions of the other two axes in space, it can be further divided into the straightness error of the X-axis in the Y direction and the straightness error of the X-axis in the Z direction.

[0067] The positioning error is used to represent the deviation between the commanded position and the actual position. Then it can be divided into the deviations between the commanded positions and the actual positions of the X-axis, Y-axis, and Z-axis. Then, according to the measured point data of the X-axis and the theoretical data in the corresponding X-axis direction, the positioning error of the machine tool is determined. Further, when measuring the positioning error, the axes other than the moving axes involved should remain stationary. However, due to the indirect measurement scheme using standard parts, the positioning error can be accurately identified through the clamping error angle and the perpendicularity data. Specifically, for example, according to the measured point data and the theoretical data in the corresponding linear axis direction, combined with the clamping error angle, the positioning error of the machine tool can be determined.

[0068] In this embodiment, according to the measured point data along the linear axis direction, the corresponding measured straight line is determined, and then the clamping error angle, perpendicularity error, and positioning error are determined. The amount of measured data is small, and the types of obtained errors are many and the accuracy is high. There is no need to use high-precision equipment for machine tool calibration, which reduces the cost of error calibration and ensures the calibration accuracy at the same time.

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

[0070] Detect the points on the first reference structure to obtain the linear axis measured point data, including:

[0071] Detect the planes on the standard part at regular intervals along the straight axis direction to obtain plane measurement point data;

[0072] Determine the straight axis error of the machine tool according to the straight axis measurement point data and the theoretical data corresponding to the first reference structure, including:

[0073] Determine the measured straight line according to the plane measurement point data;

[0074] Determine the perpendicularity error of the machine tool according to the included angle between the measured straight line and the corresponding theoretical straight axis.

[0075] Among them, the straight axis direction can be the first straight axis direction, the second straight axis direction or the third straight 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 detect the planes on the standard part at regular intervals along the straight axis direction to obtain plane measurement point data. It can be understood that it can be not along the straight axis direction, preferably along the straight axis direction. The regular interval can be the same distance or different distances, preferably the same distance, so that the obtained measurement point data is evenly distributed axially, improving the data representativeness of the straightness error calculation. For example, the machine tool controls the probe to descend to the plane on the standard part every 1 mm along the X-axis direction, that is, detect when X = 1 mm, detect when X = 2 mm... to obtain plane measurement point data.

[0077] The plane measurement point data is the data recorded in the machine tool system. In the case of no error points, the plane measurement point data should be on the same straight line. The machine tool determines the measured straight line by interpolation or fitting based on the plane measurement point data. The machine tool determines the perpendicularity error between two measured straight lines according to the included angle between the measured straight line and the theoretical straight axis, and the difference between the included angles of another measured straight line and the corresponding theoretical straight axis. For example, the plane measurement point data includes X-axis measurement point data, Y-axis measurement point data and Z-axis measurement point data, and the corresponding measured straight lines are the X-axis measured straight line, the Y-axis measured straight line and the Z-axis measured straight line. The machine tool can determine the perpendicularity error between the X-axis measured straight line and the Y-axis measured straight line, the perpendicularity error between the X-axis measured straight line and the Z-axis measured straight line, and the perpendicularity error between the Y-axis measured straight line and the Z-axis measured straight line according to the clamping error angle between the X-axis measured straight line and the theoretical X-axis, the clamping error angle between the Y-axis measured straight line and the theoretical Y-axis, and the clamping error angle between the Z-axis measured straight line and the theoretical Z-axis.

[0078] In this embodiment, since the planes on the standard part are considered to be flat and perpendicular planes, then by detecting the planes of the standard part at regular intervals along the linear axis direction to obtain plane measurement point data, and 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, with simple operation and high precision.

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

[0080] Keeping the coordinates unchanged in the third linear axis direction, detecting the planes on the standard part at regular intervals along the first linear axis direction to obtain first measurement point data, and detecting the planes on the standard part at regular intervals along the second linear axis direction to obtain second measurement point data;

[0081] Keeping the coordinates unchanged in the second linear axis direction, detecting the planes on the standard part at regular intervals along the first linear axis direction to obtain third measurement point data, and detecting the planes on the standard part at regular intervals along the third linear axis direction to obtain fourth measurement point data;

[0082] Keeping the coordinates unchanged in the first linear axis direction, detecting the planes on the standard part at regular intervals along the second linear axis direction to obtain fifth measurement point data, and detecting the planes on the standard part at regular intervals along the third linear axis direction to obtain sixth measurement point data;

[0083] Determining the measured straight line according to the plane measurement point data, including:

[0084] Determining the first measured straight line according to the first measurement point data;

[0085] Determining the second measured straight line according to the second measurement point data;

[0086] Determining the third measured straight line according to the third measurement point data;

[0087] Determining the fourth measured straight line according to the fourth measurement point data;

[0088] Determining the fifth measured straight line according to the fifth measurement point data;

[0089] Determining the sixth measured straight line according to the sixth measurement point data;

[0090] Determining the perpendicularity error of the machine tool according to the angle between the measured straight line and the theoretical linear axis, including:

[0091] Determining the perpendicularity error between the first measured straight line and the second measured straight line according to the clamping error angle between the first measured straight line and the first theoretical linear axis, and the angle between the second measured straight line and the second theoretical linear axis;

[0092] Determine the perpendicularity error between the third measured straight line and the fourth measured straight line according to 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;

[0093] Determine the perpendicularity error between the fifth measured straight line and the sixth measured straight line according to the angle between the fifth measured straight line and the third theoretical straight line axis, and the clamping error angle between the sixth measured straight line and the second theoretical straight line axis.

[0094] Among them, 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 axis straight line is also called the clamping error angle. And, the angle between the fifth measured straight line and the third theoretical straight line axis is also called the clamping error angle. It can be understood that the value of the clamping error angle can be 0. Taking the X-axis in the machine tool topology structure as the reference axis, and taking the direction of the first straight line axis as the X-axis as an example, then the perpendicularity error between the X-axis and the Y-axis can be determined according to 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 rest is similar and will not be elaborated here.

[0095] The directions of the first straight line axis, the second straight line axis and the third straight line axis are different and are straight line axes in the machine tool system, and there are certain errors before calibration. The theoretical straight line axis is regarded as the correct straight line axis. The directions of the first straight line axis, the second straight line axis and the third straight line axis can be the X-axis direction, the Y-axis direction and the Z-axis direction. In this embodiment, the direction of the first straight line axis is taken as the X-axis direction, the direction of the second straight line axis is taken as the Y-axis direction, and the direction of the third straight line axis is taken as the Z-axis direction as an example for illustration.

[0096] Specifically, keep the coordinates unchanged in the direction of the third straight line axis (Z-axis direction), and detect the plane on the standard part at intervals along the direction of the first straight line axis (X-axis direction) to obtain the first measurement point data {Data:Eyx}, and detect the plane on the standard part at intervals along the direction of the second straight line axis (Y-axis direction) to obtain the second measurement point data {Data:Exy}.

[0097] Determine the first measured straight line Lyx according to the first measurement point data {Data:Eyx}. Determine the second measured straight line Lxy according to the second measurement point data {Data:Exy}. According to 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 straight line axis (theoretical Y-axis) Determine the perpendicularity error Sxy between the first measured straight line Lyx and the second measured straight line Lxy. As Figure 5As shown, it is a schematic diagram of measuring the first measuring point data and the second measuring point data in an embodiment. On the XOZ plane of the standard part, select an appropriate height in the Z direction according to the probe length, and then move along the X-axis direction to detect the points on the standard part to obtain the first measuring point data {Data: Eyx}. The measured {Data: Eyx} is fitted to the first measured straight line: Lyx by the least squares method.

[0098] Similarly, on the stepped structure, select a plane parallel to YOZ, select an appropriate height in the Z direction according to the probe length, select a series of measuring points parallel to the Y direction, measure the change in the X coordinate to determine the straightness in the Y direction, and obtain the second measuring point data {Data: Exy}. The measured {Data: Exy} is fitted to the second measured straight line: Lxy by the least squares method.

[0099] As Figure 6 shown, it is a schematic diagram of the perpendicularity error between the first measured straight line and the second measured straight line in an embodiment. The perpendicularity error calculation formula for the first measured straight line and the second measured straight line (representing the X-axis and the Y-axis) is

[0100]

[0101] Among them, is the angle between Lxy and the Y-axis, because the X-axis is the reference axis. rotz represents the clamping error angle of the third straight line axis (Z-axis). It should be noted that the perpendicularity calculated here is the error ECOY of the Y-axis rotating around the C-axis (i.e., the Z-axis), while the error EAOY of the Y-axis rotating around the A-axis (i.e., the X-axis) is ignored because it is relatively small and cannot be accurately identified by in-machine measurement of the standard part.

[0102] In this embodiment, the coordinates in the second straight line axis direction (Y-axis direction) remain unchanged. Detect the planes on the standard part at regular intervals along the first straight line axis direction (X-axis direction) to obtain the third measuring point data {Data: Ezx}, and detect the planes on the standard part at regular intervals along the third straight line axis direction (Z-axis direction) to obtain the fourth measuring point data {Data: Exz}. Determine the third measured straight line Lzx according to the third measuring point data {Data: Ezx}. Determine the fourth measured straight line Lxz according to the fourth measuring point data {Data: Exz}. According to the clamping error angle roty between the third measured straight line Lzx and the first theoretical straight line axis (theoretical X-axis), and the angle between the fourth measured straight line Lxz and the third theoretical straight line axis (theoretical Z-axis), determine the perpendicularity error Sxz between the third measured straight line Lzx and the fourth measured straight line Lxz.

[0103] As Figure 7As shown, it is a schematic diagram of measuring the data of the third measurement point and the fourth measurement point in an embodiment. On the XOY plane of the standard part, a suitable Y coordinate is selected, a series of measurement points parallel to the X direction are selected, and the height change of the Z coordinate is measured to determine the straightness in the X direction, and the data of the third measurement point {Data: Ezx} is obtained. The measured {Data: Ezx} is fitted to the third measured straight line Lzx by the least squares method.

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

[0105] As Figure 8 shown, it is a schematic diagram of the perpendicularity error between the third measured straight line and the fourth measured straight line in an embodiment. The angle between Lzx fitted from the data of the third measurement point {Data: Ezx} and the theoretical X axis reflects the angle of the overall rotation around the Y axis when the standard block is installed on the jaw, that is, the clamping error angle roty, which is also called the clamping error angle of the standard part around the second straight line axis. Therefore, the calculation formula for the perpendicularity error between the third measured straight line and the fourth measured straight line (representing the X axis and the Z axis) is

[0106]

[0107] where is the angle between Lxz 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 in the direction of the first straight line axis (X axis direction) remain unchanged, the plane on the standard part is detected at regular intervals along the direction of the second straight line axis (Y axis direction) to obtain the data of the fifth measurement point {Data: Ezy}, and the plane on the standard part is detected at regular intervals along the direction of the third straight line axis (Z axis direction) to obtain the data of the sixth measurement point {Data: Eyz}. The fifth measured straight line Lzy is determined according to the data of the fifth measurement point {Data: Ezy}. The sixth measured straight line Lyz is determined according to the data of the sixth measurement point {Data: Eyz}. According to the angle between the fifth measured straight line Lzy and the third theoretical straight line axis (theoretical Z axis), and the clamping error angle rotx between the sixth measured straight line Lyz and the second theoretical straight line axis (theoretical Y axis), the perpendicularity error Syz between the fifth measured straight line Lzy and the sixth measured straight line Lzy is determined.

[0109] As Figure 9As shown, it is a schematic diagram of measuring the data of the fifth measuring point and the sixth measuring point in an embodiment. On the stepped surface parallel to XOY, a series of measuring points parallel to the Y-axis are selected at reasonable X coordinates, and the change in the Z coordinate is measured to determine the straightness in the Y direction, obtaining the data of the fifth measuring point {Data:Ezy}. The measured {Data:Ezy} is fitted by the least squares method to obtain the fifth measured straight line Lzy.

[0110] Similarly, on the plane where the Y coordinate is 0 on the side of the standard part, appropriate X coordinates are selected to determine a series of measuring points parallel to the Z-axis, and the change in the Y coordinate is measured to determine the straightness in the Z direction, obtaining the data of the sixth measuring point {Data:Eyz}. The measured {Data:Eyz} is fitted by the least squares method to obtain the sixth measured straight line: Lyz.

[0111] As Figure 10 shown, it is a schematic diagram of the perpendicularity error between the fifth measured straight line and the sixth measured straight line in an embodiment. The included angle rotx between the sixth measured straight line Lzy fitted from the data {data:Ezy} of the sixth measuring point and the second theoretical axis (theoretical Y-axis) reflects the angle of the overall rotation around the X-axis when the standard block is installed on the jaw, that is, the clamping error angle rotx, which is also called the clamping error angle of the standard part around the first straight axis.

[0112] The perpendicularity between the fifth measured straight line and the sixth measured straight line (representing the Y-axis and the Z-axis) is calculated as

[0113]

[0114] where is the included angle between Lzy 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] Thus, 3 items of straight axis errors are obtained, including 3 items of perpendicularity, Sxy, Sxz, Syz.

[0116] In this embodiment, the straightness deviation of the actual moving axis in space is described by two directions orthogonal to it. At the same time, the inevitable installation error is indirectly identified and separated through the fitted straight line of the measured data, so as to obtain the perpendicularity error between the three axes, and the perpendicularity error of the machine tool in each direction can be obtained, making the data more comprehensive and the calibration more accurate.

[0117] In an embodiment, according to the data of the first measuring point and the first measured straight line, the straightness error of the first straight axis of the machine tool in the direction of the second straight axis is determined;

[0118] According to the data of the second measuring point and the second measured straight line, the straightness error of the second straight axis of the machine tool in the direction of the first straight axis is determined;

[0119] Determine the straightness error of the first linear axis of the machine tool in the direction of the third linear axis according to the data of the third measuring point and the third measured straight line;

[0120] Determine the straightness error of the third linear axis of the machine tool in the direction of the first linear axis according to the data of the fourth measuring point and the fourth measured straight line;

[0121] Determine the straightness error of the second linear axis of the machine tool in the direction of the third linear axis according to the data of the fifth measuring point and the fifth measured straight line;

[0122] Determine the straightness error of the third linear axis of the machine tool in the direction of the second linear axis according to the data of the sixth measuring point and the sixth measured straight line.

[0123] Specifically, the straightness naming rule is E[error direction][measuring point data axis]. Determine the straightness error of the first linear axis of the machine tool in the direction of the second linear axis according to the data of the first measuring point and the first measured straight line:

[0124] The data of the first measuring point {Data:Eyx} is fitted by the least squares method to obtain the first measured straight line Lyx. The data of the first measuring point {Data:Eyx} is used to represent the change in the Y coordinate height to determine the straightness error in the X-axis direction. The calculation formula for the straightness error Eyx of the X-axis in the Y-axis direction is

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

[0126] It represents the Y coordinate value y of the i-th point of the measuring point data {Data:Eyx} i , and subtracts it from the Y coordinate value y of the i-th point of the fitted straight line Lyx i .

[0127] Determine the straightness error of the second linear axis of the machine tool in the direction of the first linear axis according to the data of the second measuring point and the second measured straight line:

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

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

[0130] It is expressed that the X - coordinate value of the i - th point of the measured - point data {Data:Exy} is subtracted from the X - coordinate value of the i - th point of the fitted straight line Lxy.

[0131] According to the third measured - point data and the third measured straight line, determine the straightness error of the first linear axis of the machine tool in the third linear - axis direction:

[0132] The third measured - point data {Data:Ezx} is fitted by the least - squares method to obtain the third measured straight line Lzx. The calculation formula for the straightness error Ezx of the X - axis in the Z - axis direction is

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

[0134] It is expressed that the Z - coordinate value of the i - th point of the measured - point data {Data:Ezx} is subtracted from the Z - coordinate value of the i - th point of the fitted straight line Lzx.

[0135] According to the fourth measured - point data and the fourth measured straight line, determine the straightness error of the third linear axis of the machine tool in the first linear - axis direction:

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

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

[0138] It is expressed that the X - coordinate value of the i - th point of the measured - point data {Data:Exz} is subtracted from the X - coordinate value of the i - th point of the fitted straight line Lxz.

[0139] According to the fifth measured - point data and the fifth measured straight line, determine the straightness error of the second linear axis of the machine tool in the third linear - axis direction:

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

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

[0142] It is expressed that the Z - coordinate value of the i - th point of the measured - point data {Data:Ezy} is subtracted from the Z - coordinate value of the i - th point of the fitted straight line Lzy.

[0143] According to the sixth measured - point data 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:

[0144] The sixth measured - point data {Data:Eyz} is fitted by the least - squares method to obtain the sixth measured straight line Lyz. The calculation formula for the straightness Eyz of the Z - axis in the Y - axis direction is

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

[0146] It is expressed that the Y - coordinate value of the i - th point of the measured - point data {Data:Eyz} is subtracted from the Y - coordinate value of the i - th point of the fitted straight line Lyz.

[0147] In this embodiment, since the machine tool detects points on the detected object during detection, only the offset in one direction can be detected at a time. And the offset on one coordinate axis may have two directions. Therefore, through six detections to obtain the measured - point data and combining with the obtained measured straight line, the full - term detection of the straightness error of the three linear axes of the machine tool in the orthogonal direction can be obtained, 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 respectively perform error positioning on two reference directions;

[0149] Detect points on the first reference structure to obtain linear - axis measured - point data, including:

[0150] Each time a certain distance is moved, detect the reference step surface of the stepped structure to obtain the stepped measured - point data representing the reference direction;

[0151] According to the linear - axis measured - point data and the theoretical data corresponding to the first reference structure, determine the linear - axis error of the machine tool, including:

[0152] According to the stepped measured - point data representing the reference direction and the theoretical data corresponding to the reference direction of the step surface, determine the positioning error of the reference direction.

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

[0154] Taking one reference direction of the step surface as the Z-axis direction and the Z direction corresponding to the step height h, and the other direction as the X-axis direction and the X direction corresponding to the step width d as an example for illustration. Then, when measuring the positioning error in the X-axis direction, every time a distance is moved along the Z-axis direction, this distance is preferably h, 2h, etc. Every other distance, the step kick surface is detected once to obtain the step measurement point data representing the step width. According to the step measurement point data representing the step tread surface width. Then, the machine tool can determine the positioning error in the X-axis direction based on the step measurement point data representing the step width and the step width d.

[0155] Taking one reference direction of the step surface as the X-axis direction and the X direction corresponding to the step width d, and the other reference direction as the Z-axis direction and the Z direction corresponding to the step height h as an example for illustration. Then, when measuring the positioning error in the Z-axis direction, every time a distance is moved along the X-axis direction, this distance is preferably d, 2d, etc. Every other distance, the step tread surface is detected once to obtain the step measurement point data representing the step height. Then, the machine tool can 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 available for positioning, the reference step surface of the step structure can be detected by moving a certain distance along one reference direction of the step surface each time, and the step measurement point data representing the other reference direction can be obtained. Then, based on the corresponding theoretical data, the positioning error can be determined. Thus, the positioning error of the machine tool can be simply measured by a standard part, reducing the cost.

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

[0158] Determining the positioning error of the reference direction according to the step measurement point data representing the reference direction and the theoretical data corresponding to the reference direction of the step surface includes:

[0159] 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 according to the clamping error angle between the first measured straight line and the first theoretical linear axis; the first measured straight line is determined according to the first measurement point data; the first measurement point data is obtained by detecting the plane of the standard part at intervals along the first linear axis while keeping the coordinates in the third linear axis direction unchanged;

[0160] Determine the error correction value of the third linear axis according to the coordinates on the second linear axis and the clamping error angle of the standard part around 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 according to the clamping error angle between the third measured straight line and the first theoretical linear axis; the third measured straight line is determined according to the third measuring point data; the third measuring point data is obtained by detecting 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] Determine the error correction value of the second linear axis according to the step width, step height and the clamping error angle of the standard part around the second linear axis;

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

[0164] Determine the perpendicularity correction value according to the perpendicularity between the third measured straight line and the fourth measured straight line and the theoretical data corresponding to the direction of the first linear axis;

[0165] Determine the positioning error in the direction of the first linear axis according to 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 measuring point data representing the direction of the first linear axis and the theoretical data corresponding to the direction of the first linear axis.

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

[0167] Specifically, taking the direction of the third linear axis as the Z-axis direction, the direction of the first linear axis as the X-axis direction, and the direction of the second linear axis as the Y-axis direction as an example for illustration. As Figure 11 shown, it is a schematic diagram of X-axis positioning error measurement in an embodiment. The schematic diagram of the detection path is shown in the right figure. The machine tool obtains the clamping error angle rotz of the standard part around the third linear axis, the step width is d, the step height is h, then the A and C axes are zeroed, and a suitable Y coordinate y Exx (i.e., the coordinate on the second linear axis) is selected. The probe moves along the Z-axis direction at a height of h each time and detects along the X-axis direction until the step kick surface, then the step measuring point data {Data:X Exx} is obtained. The theoretical width of the step is d and the theoretical height is h, and the theoretical data {Data:X ideal} of the X-direction step as a measuring scale can be calculated.

[0168] According to 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 be skewed, resulting in an error in the theoretical data of the measuring scale. As Figure 12As shown, it is a schematic diagram of the position deviation of the measurement point caused by the clamping error angle of the standard part around the third straight axis. Then, in order to eliminate the influence of the installation error rotz, according to the coordinate y on the second straight axis Exx and the clamping error angle rotz of the standard part around the third straight axis, determine the error correction value ΔX of the third straight axis rotz :

[0169]

[0170] wherein, the angle of rotz is small, y Exx ≈y Exx / cos(rotz), the Y coordinates of the measurement point set {Data:X Exx} are the same, so the correction values of this item are the same.

[0171] In addition to the installation error rotz, the clamping error angle roty of the standard part around the second straight axis causes the step surface to tilt, making the actual distance between the measuring scales As Figure 13 shown, it is a schematic diagram of the position deviation of the measurement point caused by the clamping error angle of the standard part around the second straight axis in an embodiment. Then, in order to eliminate the influence of the installation error roty, according to the step width d, the step height h, and the clamping error angle roty of the standard part around the second straight axis, determine its correction value ΔX roty is

[0172]

[0173] In addition to the installation error, according to the perpendicularity measurement result, the perpendicularity Sxz between the third measured straight line and the fourth measured straight line is not 0, and the machine tool reference axis in this embodiment is the X axis. Therefore, the movement of the X axis is used to compensate for the perpendicularity error. Then, according to the perpendicularity Sxz between the third measured straight line and the fourth measured straight line and the theoretical data {Data:X ideal}| i , determine the perpendicularity correction value ΔComp Sxz | i at the measuring point i as

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

[0175] wherein, ΔComp Sxz | i represents the coordinate axis in the first axis direction.

[0176] In summary, according to the error correction value ΔX of the third straight axisrotz , the error correction value ΔX of the second linear axis roty *i, perpendicularity correction value ΔComp Sxz | i , and the difference between the step measurement point data in 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 , determine that the X-axis positioning error data is calculated as

[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, it is necessary to remove the influence of the clamping error angle when calculating the positioning error, including 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 according to the step measurement point data and the corresponding theoretical data, and the positioning error of the machine tool in the direction of the first linear axis can be accurately obtained, and the cost is low.

[0179] In one embodiment, the standard part includes a rectangular tooth structure; detecting points on the first reference structure to obtain linear axis measurement point data, including:

[0180] Detecting tooth feature points on the rectangular tooth structure to obtain tooth feature measurement point data;

[0181] According to the linear axis measurement point data and the theoretical data corresponding to the first reference structure, determine the linear axis error of the machine tool, including:

[0182] Determine the positioning error of the machine tool in the direction of the second linear axis according to the tooth feature measurement point data and the tooth feature theoretical data.

[0183] Among them, the tooth feature point refers to a point that can represent the tooth width or the groove width. The machine tool detects the tooth feature points on the rectangular tooth structure to obtain the tooth feature measurement point data {Data:Y Eyy}| i . According to the tooth feature measurement point data {Data:Y Eyy}| i and the theoretical data {Data:Y ideal}|i Determine the positioning error E in the second linear axis direction of the machine tool based on the difference yy | i , E yy (i = 1,..n) can form an interpolation table for positioning errors. The positioning errors outside the corresponding detection points can be obtained through 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] Wherein, K p =(y i -y p ) / (y p -y i-1 )

[0186] Specifically, as Figure 14 shown, it is a schematic diagram of Y-axis positioning error measurement in an embodiment. The wall thickness and width of the slot hole 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, select detection feature points on the sides of each slot in the Y direction, measure the Y coordinates of each measurement point, and obtain the tooth feature measurement point data {Data:Y Eyy}. During the measurement process, the X coordinates and Z coordinates of the detection points remain the same, and the installation error can be basically ignored. Therefore, the Y-axis positioning error can be calculated as

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

[0188] In this embodiment, by detecting the tooth feature points on the rectangular tooth structure, obtaining the tooth feature measurement point data, and based on the tooth feature measurement point data and the tooth feature theoretical data, the positioning error in the second direction of the machine tool can be accurately determined, and the cost is low.

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

[0190] Determine the positioning error in the reference direction according to the step measurement point data representing the reference direction and the theoretical data corresponding to the reference direction of the step surface, including:

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

[0192] Determine the error correction value of the second straight axis according to the step width, step height and the clamping error angle of the standard part around the second straight axis.

[0193] Determine the positioning error in the direction of the third straight axis according to the error of the second straight axis and the difference between the step measuring point data characterizing the direction of the third straight axis and the corresponding theoretical data in the direction of the third straight axis.

[0194] Among them, the clamping error angle of the standard part around the second straight axis is obtained after the machine tool is calibrated.

[0195] Specifically, as Figure 15 shown, it is a schematic diagram of Z-axis positioning error measurement in an embodiment. The theoretical width of the step is d and the theoretical height is h. Then, the A and C axes are zeroed, and a suitable Y coordinate y Exx is selected. The probe moves a distance along the X-axis direction with a width of d each time and detects until the step surface, then the measuring point data {Data:Z Ezz} of the third straight axis is obtained. Due to the clamping error angle roty of the standard part around the second straight axis, the step surface of the standard part is not parallel to the reference plane of the established coordinate system. As Figure 16 shown, it is a schematic diagram of the position deviation of the measuring point caused by the clamping error angle of the standard part around the second straight axis in another embodiment. The theoretical size of the measuring scale changes during the actual measurement of the positioning error. Specifically, according to the step width d, step height h and the clamping error angle roty of the standard part around the second straight axis, the error correction value ΔZ roty of the second straight axis is determined.

[0196]

[0197] In summary, according to the error ΔZ roty *i of the second straight axis, and the difference between the step measuring point data {Data:Z Ezz}| i characterizing the direction of the third straight axis and the corresponding theoretical data {Data:Z ideal}| i in the direction of the third straight axis, 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, due to the clamping error angle existing in the machine tool, the influence of the clamping error angle needs to be removed when calculating the positioning error, including the error correction value of the second linear axis. Then, the positioning error of the machine tool is determined according to the step measurement point data and the corresponding theoretical data, and the positioning error of the machine tool in the direction of the first linear axis can be accurately obtained, and the cost is low.

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

[0202] After the rotating axis rotates, detect the reference point on the second reference structure to obtain the measuring point data of the rotating axis, including:

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

[0204] According to the measuring point data of the rotating axis and the corresponding theoretical data of the rotating axis, determine the rotating axis error of the machine tool, including:

[0205] Determine the center position of the measured circular surface according to at least three ball positions to obtain the measured axis center position;

[0206] Determine the axis center position error of the rotating axis of the machine tool according to the measured axis center position and the theoretical axis position.

[0207] Among them, the machine tool is a five-axis numerical control machine tool. The second reference structure includes a spherical structure. The spherical structure can be a sphere, a hemisphere, other spherical surfaces, etc. The rotating axes of the machine tool include the A axis and the C axis, and the errors of the A axis and the C axis can both be calibrated according to the method in this embodiment. The reference point of the spherical structure can be the center of the ball or the highest point of the spherical surface, etc., preferably the center of the ball. Similarly, the ball position can be the center position of the ball or the highest point position of the spherical surface.

[0208] Specifically, the machine tool can detect the reference point once in the initial state, and obtain the reference point once every subsequent rotation to obtain at least three ball positions. Determine the center position of the measured circular surface PL according to at least three ball positions, and this center position is the measured axis center position. The machine tool can determine the axis center position error of the rotating axis of the machine tool according to the difference between the measured axis center position and the theoretical axis center position.

[0209] Further, taking the rotating axis as the C axis as an example, the machine tool determines the normal vector of the surface of the measured circular surface PL1 Furthermore, the angle AOC between the surface normal vector and the theoretical X-axis, as well as the surface normal vector and the angle BOC between the theoretical Y-axis can be determined.

[0210] As Figure 17 shown, it is a schematic diagram of C-axis calibration in an 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 workbench, clamp the standard part on the workbench, ensure that the spherical surface of the standard part is smooth, and zero the X, Y, Z, A, and C axes.

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

[0213] ③ Use the probe to measure the spherical surface at a constant detection speed, and successively measure 5 points at the top of the ball and the equator of the spherical surface. Combine the probe error and use the least squares method to fit its center as the data of measurement point 1.

[0214] ④ Repeat step ③ and successively measure points 2 to 4 corresponding to the C-axis at 90°, 180°, and 270°.

[0215] ⑤ Fit the plane PL1 according to points 1 to 4, and then fit the circle O1 on the plane PL1 as shown in Figure 17 .

[0216] ⑥ Calculate the position of the C-axis line, where the Z coordinate has no reference significance.

[0217]

[0218] ⑦ As Figure 18 shown, it is a schematic diagram of C-axis line fitting and error decomposition in an embodiment. The C-axis line vector is equal to the surface normal vector of the PL1 plane 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 the A-axis as an example, the machine tool determines the surface normal vector of the actually measured circular surface PL2 Furthermore, the surface normal vector can be determined and the angle between the theoretical Y-axis, and the surface normal vector and the angle between the theoretical Z-axis.

[0220] The measurement principle of the A-axis line is similar to that of the C-axis. However, since the spherical surface of the standard ball cannot measure different longitude and latitude feature points on the spherical surface well after rotating with the A-axis, the measurement stroke of the A-axis error is set to -15° to 15°. Optionally, by optimizing the installation method of the standard spherical surface and adding a spherical support seat, the measurement azimuth of the A-axis can be increased, not limited to -15° to 15°. The specific measurement steps are as follows:

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

[0222] ②Use a probe to measure the spherical surface at a constant detection speed. Sequentially measure five points on the top of the sphere and the equator of the spherical surface. Combine the probe error and use the least squares method to fit its center as the data of measurement point 1.

[0223] ③Repeat step ② to sequentially measure points 2 - 5 corresponding to A axes of -7.5°, 0°, 7.5°, and 15°.

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

[0225] ⑤Calculate the position of the A - axis according to the following formula:

[0226]

[0227] ⑥The A - axis vector is equal to the normal vector of plane PL2 Furthermore, the normal vector of the plane can be determined the included angle between the normal vector of the plane and the theoretical Y - axis, and the normal vector of the plane the included angle between the normal vector of the plane and the theoretical Z - axis.

[0228] In this embodiment, multiple ball positions are obtained by rotating the rotating axis, so as to determine the measured axis center position. According to the measured axis center position and the theoretical axis position, the axis center position error of the rotating axis of the machine tool is determined. Determining the axis center position error of the rotating axis of the machine tool can realize the calibration of the linear axis and the rotating axis through a standard part, reducing the cost.

[0229] In an embodiment, the standard part further includes a circular hole structure. The method further includes:

[0230] Detect at least three points on the inner wall of the circular hole structure, and determine the position of the center of the circular hole according to the at least three points;

[0231] Establish the measurement coordinate system of the machine tool according to the position of the center of the circular hole and the reference axis of the machine tool.

[0232] Among them, the measurement coordinate system of the machine tool is the coordinate system inside the machine tool system. The machine tool moves according to the coordinate system established by itself, such as moving along the X - axis direction. Before calibration, there is a certain error in the measurement coordinate system. The reference axis of the machine tool can be set according to requirements and can be one of the X - axis, Y - axis, and Z - axis, preferably the X - axis.

[0233] Specifically, the machine tool detects at least three points on the inner wall of the circular hole structure. Based on at least three points, a circle can be determined, and then the position of the center point of the circular hole can be determined. The position of the circular hole point can be three-dimensional coordinates. Then, based on the reference axis of the machine tool, the measurement coordinate system of the machine tool 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 where the circular hole is located and combining it with the position of the center point of the circular hole, the three-dimensional coordinate position of the center point of the circular hole 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 according to the size of the circular hole and the size of the standard part.

[0235] For example, according to Figure 1 the standard part and the marking position of the clamping chuck, their rough positions are basically the same after installation. The machine tool first detects four points in the X and Y directions of the circular hole to obtain the center point of the circular hole, then exits the circular hole and detects the origin of the z-axis; then, the upper right corner of the standard part is used as the coordinate origin according to the design size of the circular hole; after the detected point [x0, y0, z0] is corrected according to the probe calibration data, such as combined with the standard axis of the machine tool such as the X axis to complete the establishment of the measurement coordinate system. The probe calibration data is the value added to the data of the points measured subsequently.

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

[0237] In one embodiment, as Figure 20 shown, it is a schematic flow chart of the error calibration method of the machine tool in another embodiment. Figure 20 It includes the following steps:

[0238] S100: Probe installation and calibration.

[0239] Specifically, install a high-precision probe and calibrate the probe to obtain the length, circular runout, and pre-travel of the probe at a fixed detection speed. When actually detecting, the true measurement point = recorded point + probe calibration data. For the convenience of description, the probe calibration value is expressed as φ_probe here. The detection accuracy of the calibrated probe should be better than ±0.003 mm.

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

[0241] Specifically, when the machine tool returns to zero, the accuracy of the workbench level and the X-axis should be maintained well, and subsequent calibrations are carried out on this basis. Clean the workbench and standard parts to ensure that the working space of the machine tool is clean and free of obstacles during measurement. Clamp the standard part on the workbench. The designed marking position features can ensure the rough position of the standard part during installation by matching the markings of the fixture, which facilitates the automation of the calibration process. Establish the measurement coordinate system by detecting the round hole structure on the standard part and the Z-axis origin, and combining with the reference axis of the machine tool.

[0242] S300: Measurement of the perpendicularity of the X-Y axis, X-Z axis, and Y-Z axis.

[0243] Specifically, the perpendicularity Sxy of the X-Y axis, the perpendicularity Sxz of the X-Z axis, and the perpendicularity Syz of the Y-Z axis have been obtained above.

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

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

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

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

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

[0249] Specifically, it includes at least the axis position errors XOC and YOC of the C-axis, the angle AOC between the C-axis vector and the theoretical axis vector in the X direction, the angle BOC between the C-axis vector and the theoretical axis vector in the Y direction; and the axis position errors XOA and YOA of the A-axis, 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 a five-axis machine tool can be classified into linear axis errors and rotary axis errors according to the axis type. Among them, the linear axis errors include positioning errors, straightness errors, perpendicularity errors, and angular errors. The rotary axis errors include positioning errors, straightness errors, angular errors, and assembly errors. Specifically, it includes the positioning errors, straightness, and perpendicularity of the linear axes, and the axis position and angular errors of the A and C axes.

[0251] For the positioning error of the linear axis, a workpiece with a stepped shape can be designed for calibration. 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] For the straightness error of the linear axis, a plane parallel to the common reference plane can be designed for calibration. The probe detects the characteristic points of a straight line on this plane to obtain the levelness of the linear axis.

[0253] For the perpendicularity error between axes, it can be solved by combining the levelness errors of the two axes.

[0254] For the errors of the rotary axis, a standard spherical surface is designed for calibration. The spherical surface features rotate with the rotary axis. The probe detects the centers of the spherical surface at different positions, and then fits the actual rotary plane. By comparing it with the theoretical plane and the axis vector, the axis error of the rotary axis can be obtained.

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

[0256] In this embodiment, through a standard part, the linear axis errors and rotary axis errors of the machine tool can be calibrated, which can improve the calibration efficiency of the geometric errors of the machine tool while ensuring accuracy.

[0257] In one embodiment, a method for calibrating the errors of a machine tool is applied to the machine tool. A standard part is placed on the machine tool. The standard part includes a first reference structure for calibrating the linear axis errors and a second reference structure for calibrating the rotary axis errors. The first reference structure includes a planar structure, and the linear axis errors include perpendicularity errors; the linear axis errors include 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), detecting at least three points on the inner wall of the round hole structure, and determining the position of the center point of the round hole according to the at least three points.

[0259] Step (a2), establishing a measurement coordinate system of the machine tool according to the position of the center point of the round hole and the reference axis of the machine tool; the measurement coordinate system is used for the controlled movement of the machine tool.

[0260] In step (a3), with the coordinates in the third linear axis direction remaining unchanged, detect the planes on the standard part at regular intervals along the first linear axis direction to obtain the first measurement point data, and detect the planes on the standard part at regular intervals along the second linear axis direction to obtain the second measurement point data.

[0261] In step (a4), with the coordinates in the second linear axis direction remaining unchanged, detect the planes on the standard part at regular intervals along the first linear axis direction to obtain the third measurement point data, and detect the planes on the standard part at regular intervals along the third linear axis direction to obtain the fourth measurement point data.

[0262] In step (a5), with the coordinates in the first linear axis direction remaining unchanged, detect the planes on the standard part at regular intervals along the second linear axis direction to obtain the fifth measurement point data, and detect the planes on the standard part at regular intervals along the third linear axis direction to obtain the sixth measurement point data.

[0263] In step (a6), determine the first actually measured straight line based on the first measurement point data.

[0264] In step (a7), determine the second actually measured straight line based on the second measurement point data.

[0265] In step (a8), determine the third actually measured straight line based on the third measurement point data.

[0266] In step (a9), determine the fourth actually measured straight line based on the fourth measurement point data.

[0267] In step (a10), determine the fifth actually measured straight line based on the fifth measurement point data.

[0268] In step (a11), determine the sixth actually measured straight line based on the sixth measurement point data.

[0269] In step (a12), determine the perpendicularity error between the first actually measured straight line and the second actually measured straight line based on the clamping error angle between the first actually measured straight line and the first theoretical straight line axis, and the angle between the second actually measured straight line and the second theoretical straight line axis.

[0270] In step (a13), determine the perpendicularity error between the third actually measured straight line and the fourth actually measured straight line based on the clamping error angle between the third actually measured straight line and the first theoretical straight line axis, and the angle between the fourth actually measured straight line and the third theoretical straight line axis.

[0271] In step (a14), determine the perpendicularity error between the fifth actually measured straight line and the sixth actually measured straight line based on the angle between the fifth actually measured straight line and the third theoretical straight line axis, and the clamping error angle between the sixth actually measured straight line and the second theoretical straight line axis.

[0272] Step (a15): Determine the straightness error of the first linear axis of the machine tool in the direction of the second linear axis according to the first measuring point data and the first actually measured straight line.

[0273] Step (a16): Determine the straightness error of the second linear axis of the machine tool in the direction of the first linear axis according to the second measuring point data and the second actually measured straight line.

[0274] Step (a17): Determine the straightness error of the first linear axis of the machine tool in the direction of the third linear axis according to the third measuring point data and the third actually measured straight line.

[0275] Step (a18): Determine the straightness error of the third linear axis of the machine tool in the direction of the first linear axis according to the fourth measuring point data and the fourth actually measured straight line.

[0276] Step (a19): Determine the straightness error of the second linear axis of the machine tool in the direction of the third linear axis according to the fifth measuring point data and the fifth actually measured straight line.

[0277] Step (a20): Determine the straightness error of the third linear axis of the machine tool in the direction of the second linear axis according to the sixth measuring point data and the sixth actually measured straight line.

[0278] Step (a21): Detect the reference step surface of the step structure every time a certain distance is moved, and obtain the step measuring point data representing the direction of the first linear axis.

[0279] Step (a22): 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 according to the clamping error angle between the first actually measured straight line and the first theoretical linear axis.

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

[0281] Step (a24): 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 according to the clamping error angle between the third actually measured straight line and the first theoretical linear axis.

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

[0283] Step (a26): Obtain the perpendicularity between the third actually measured straight line and the fourth actually measured straight line.

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

[0285] Step (a28), determine the positioning error in the direction of the first linear axis 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 stepped measuring point data representing the direction of the first linear axis and the theoretical data corresponding to the direction of the first linear axis.

[0286] Step (a29), detect the tooth feature points on the rectangular tooth structure to obtain the tooth feature measuring point data.

[0287] Step (a30), determine the positioning error in the direction of the second linear axis of the machine tool based on the tooth feature measuring point data and the tooth feature theoretical data.

[0288] Step (a31), detect the reference stepped surface of the stepped structure every time a certain distance is moved to obtain the stepped measuring point data representing the direction of the third linear axis.

[0289] Step (a32), 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.

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

[0291] Step (a34), determine the positioning error in the direction of the third linear axis based on the error of the second linear axis and the difference between the stepped measuring point data representing the direction of the third linear axis and the theoretical data corresponding to the direction of the third linear axis.

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

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

[0294] Step (a37), determine the axis center position error of the rotation axis of the machine tool based on the measured axis center position and the theoretical axis position.

[0295] In this embodiment, a standard part is placed on a machine tool. The standard part includes a first reference structure for calibrating the error of a linear axis and a second reference structure for calibrating the error of a rotary axis. By detecting the points on the first structure and combining with the theoretical data corresponding to the first reference structure, the error of the linear axis of the machine tool is determined; after the rotary axis rotates, the reference points on the second reference structure are detected and combined with the theoretical data corresponding to the rotary axis to determine the error of the rotary axis of the machine tool. It is possible to measure the error of the linear axis and the error of the rotary axis of the machine tool with one standard part. The obtained error types are numerous and the accuracy is high. There is no need to use high-precision equipment for calibrating the machine tool, reducing the cost of error calibration.

[0296] It should be understood that although the steps in the above Figure 4 and Figure 20 flowcharts are shown in sequence according to the arrows, and the steps in steps (a1) to (a37) are shown in sequence according to the labels, these steps are not necessarily executed in the order indicated by the arrows or numbers. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, Figure 4 and Figure 20 at least a part of the steps in

[0297] In one embodiment, a numerical control machine tool is provided, and its internal structure diagram can be as Figure 21 shown. The computer device includes a processor, a memory, a communication interface, a display screen, and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a carrier network, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it realizes a method for calibrating the error of a machine tool. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device can be a touch layer covered on the display screen, or a button, a trackball, or a touchpad set on the shell of the computer device, or an external keyboard, a touchpad, or a mouse, etc.

[0298] Those skilled in the art can understand,Figure 21 The structure shown is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different component layout.

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

[0300] In one embodiment, a numerically controlled machine tool is provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the steps of the above method embodiments are implemented.

[0301] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above method embodiments are implemented.

[0302] In one embodiment, a computer program product or a computer program is provided. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the steps in the above method embodiments.

[0303] Those of ordinary skill in the art can understand that all or part of the processes of implementing the methods in the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it may include the processes in the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium used in the various embodiments provided in this application may include at least one of non-volatile and volatile memories. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical memory, etc. Volatile memory may 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 are only the preferred embodiments of the present application, and thus do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall similarly be included within the patent protection scope of the present application.

Claims

1. An error calibration method for a machine tool, characterized in that, Applied to a machine tool on which a standard part is placed, the standard part includes a first reference structure for calibrating the error of a linear axis and a second reference structure for calibrating the error of a rotary axis; the method includes: Detect points on the first reference structure to obtain linear axis measurement point data; Determine the linear axis error of the machine tool according to the linear axis measurement point data and the theoretical data corresponding to the first reference structure; After the rotary axis rotates, detect reference points on the second reference structure to obtain rotary axis measurement point data; Determine the rotary axis error of the machine tool according to the rotary axis measurement point data and the theoretical data corresponding to the rotary axis.

2. The method according to claim 1, wherein The step of determining the linear axis error of the machine tool according to the linear axis measurement point data and the theoretical data corresponding to the first reference structure includes: For the first reference structure, determine the measured straight line corresponding thereto according to the measurement point data along the linear axis direction; Determine the perpendicularity error of the linear axis of the machine tool according to the included angle between the measured straight line and the corresponding theoretical linear axis; Determine the straightness error of the machine tool according to the measurement point data and the corresponding measured straight line; Determine the positioning error of the machine tool according to the measurement point data and the theoretical data in the corresponding linear axis direction.

3. The method according to claim 1, wherein The first reference structure includes a planar structure, and the linear axis error includes a perpendicularity error; The step of detecting points on the first reference structure to obtain linear axis measurement point data includes: Detect the planes on the standard part at intervals along the linear axis direction to obtain plane measurement point data; The step of determining the linear axis error of the machine tool according to the linear axis measurement point data and the theoretical data corresponding to the first reference structure includes: Determine the measured straight line according to the plane measurement point data; Determine the perpendicularity error of the machine tool according to the included angle between the measured straight line and the corresponding theoretical linear axis.

4. The method according to claim 3, wherein The step of detecting the planes on the standard part at intervals along the linear axis direction to obtain plane measurement point data includes: With the coordinates in the third linear axis direction unchanged, detect the planes on the standard part at intervals along the first linear axis direction to obtain first measurement point data, and detect the planes on the standard part at intervals along the second linear axis direction to obtain second measurement point data; With the coordinates in the second linear axis direction unchanged, detect the planes on the standard part at intervals along the first linear axis direction to obtain third measurement point data, and detect the planes on the standard part at intervals along the third linear axis direction to obtain fourth measurement point data; With the coordinates in the first linear axis direction unchanged, detect the planes on the standard part at intervals along the second linear axis direction to obtain fifth measurement point data, and detect the planes on the standard part at intervals along the third linear axis direction to obtain sixth measurement point data; The step of determining the measured straight line according to the plane measurement point data includes: Determine the first measured straight line according to the first measurement point data; Determine the second measured straight line according to the second measurement point data; Determine the third measured straight line according to the third measurement point data; Determine the fourth measured straight line according to the fourth measurement point data; Determine the fifth measured straight line based on the fifth measuring point data; Determine the sixth measured straight line based on the sixth measuring point data; Determining the perpendicularity error of the machine tool according to the angle between the measured straight line and the theoretical straight line axis includes: Determine the perpendicularity error between the first measured straight line and the second measured straight line according to 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 third measured straight line and the fourth measured straight line according to 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 fifth measured straight line and the sixth measured straight line according to the angle between the fifth measured straight line and the third theoretical straight line axis, and the clamping error angle between the sixth measured straight line and the second theoretical straight line axis.

5. The method according to claim 4, characterized in that, The method further includes: Determine the straightness error of the first straight line axis of the machine tool in the direction of the second straight line axis according to the first measuring point data and the first measured straight line; Determine the straightness error of the second straight line axis of the machine tool in the direction of the first straight line axis according to the second measuring point data and the second measured straight line; Determine the straightness error of the first straight line axis of the machine tool in the direction of the third straight line axis according to the third measuring point data and the third measured straight line; Determine the straightness error of the third straight line axis of the machine tool in the direction of the first straight line axis according to the fourth measuring point data and the fourth measured straight line; Determine the straightness error of the second straight line axis of the machine tool in the direction of the third straight line axis according to the fifth measuring point data and the fifth measured straight line; Determine the straightness error of the third straight line axis of the machine tool in the direction of the second straight line axis according to the sixth measuring point data and the sixth measured straight line.

6. The method according to claim 1, characterized in that The straight line axis error includes a positioning error; the first reference structure includes a stepped structure; the stepped structure is used to respectively perform error positioning on two reference directions; Detecting points on the first reference structure to obtain straight line axis measuring point data includes: Detect the reference step surface of the stepped structure every time a certain distance is moved to obtain step measuring point data characterizing the reference direction; Determining the straight line axis error of the machine tool according to the straight line axis measuring point data and the theoretical data corresponding to the first reference structure includes: Determine the positioning error of the reference direction according to the step measuring point data characterizing the reference direction and the theoretical data corresponding to the reference direction of the reference step surface.

7. The method according to claim 6, characterized in that, The reference direction is the direction of the first straight line axis; Determining the positioning error of the reference direction according to the step measuring point data characterizing the reference direction and the theoretical data corresponding to the reference direction of the reference step surface includes: Obtain the clamping error angle of the standard part around the third straight axis; the clamping error angle of the standard part around the third straight axis is determined according to the clamping error angle between the first measured straight line and the first theoretical straight axis; the first measured straight line is determined according to the first measurement point data; the first measurement point data is obtained by detecting the plane of the standard part at intervals along the first straight axis while keeping the coordinate in the direction of the third straight axis unchanged; Determine the error correction value of the third straight axis according to the coordinate on the second straight axis and the clamping error angle of the standard part around the third straight axis; Obtain the clamping error angle of the standard part around the second straight axis; the clamping error angle of the standard part around the second straight axis is determined according to the clamping error angle between the third measured straight line and the first theoretical straight axis; the third measured straight line is determined according to the third measurement point data; the third measurement point data is obtained by detecting the plane on the standard part at intervals along the first straight axis while keeping the coordinate in the direction of the second straight axis unchanged; Determine the error correction value of the second straight axis according to the step width, step height and the clamping error angle of the standard part around the second straight axis; Obtain the perpendicularity between the third measured straight line and the fourth measured straight line; Determine the perpendicularity correction value according to the perpendicularity between the third measured straight line and the fourth measured straight line and the theoretical data corresponding to the direction of the first straight axis; Determine the positioning error in the direction of the first straight axis according to 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 characterizing the direction of the first straight axis and the theoretical data corresponding to the direction of the first straight axis; 8. The method according to claim 1, wherein The standard part includes a rectangular tooth structure; The detecting points on the first reference structure to obtain the straight axis measurement point data includes: Detecting the tooth feature points on the rectangular tooth structure to obtain the tooth feature measurement point data; The determining the straight axis error of the machine tool according to the straight axis measurement point data and the theoretical data corresponding to the first reference structure includes: Determining the positioning error in the direction of the second straight axis of the machine tool according to the tooth feature measurement point data and the tooth feature theoretical data; 9. The method according to claim 6, wherein The reference direction of the reference step surface is the direction of the third straight axis; The determining the positioning error in the reference direction according to the step measurement point data characterizing the reference direction and the theoretical data corresponding to the reference direction of the reference step surface includes: Obtain the clamping error angle of the standard part around the second straight axis; the clamping error angle of the standard part around the second straight axis is determined according to the clamping error angle between the third measured straight line and the first theoretical straight axis; the third measured straight line is determined according to the third measurement point data; the third measurement point data is obtained by detecting the plane on the standard part at intervals along the first straight axis while keeping the coordinate in the direction of the second straight axis unchanged; Determine the error correction value of the second straight axis according to the step width, step height and the clamping error angle of the standard part around the second straight axis; Determine the positioning error in the direction of the third linear axis 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.

10. The method according to claim 1, wherein The second reference structure includes a spherical structure; After the rotation axis rotates, detecting a reference point on the second reference structure to obtain rotation axis measurement point data, including: Controlling the rotation axis to rotate at least twice, and detecting the reference point of the spherical structure after rotation to obtain at least three ball positions; Determining the rotation axis error of the machine tool according to the rotation axis measurement point data and the theoretical data corresponding to the rotation axis, including: Determining the center position of the measured circular surface according to the at least three ball positions to obtain the measured axis center position; Determining the axis center position error of the rotation axis of the machine tool according to the measured axis center position and the theoretical axis position.

11. The method according to any one of claims 1 to 10, characterized in that, The standard part includes a circular hole structure; the method further includes: Detecting at least three points on the inner wall of the circular hole structure, and determining the position of the center point of the circular hole according to the at least three points; Establishing a measurement coordinate system of the machine tool according to the position of the center point of the circular hole and the reference axis of the machine tool.

12. A numerical control 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, the steps of the method according to any one of claims 1 to 11 are implemented.

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

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