High-precision geometric error detection method and system for five-axis numerical control machining

Abstract

The invention relates to the technical field of five-axis numerical control machining error detection, in particular to a high-precision geometric error detection method and system for five-axis numerical control machining, and the method comprises the steps: obtaining a height error value and a height error matrix of a measurement point on the surface of a workbench through a laser interferometer; determining the final possibility that the height error matrix deforms in a corresponding area on the surface of the workbench; determining the deformation quantity of the surface of the workbench measured each time; determining the most recently measured deformation quantity change rate of the surface of the workbench; determining the final deformation quantity of the position of the workpiece on the surface of the workbench at each moment; and compensating the five-axis numerical control machine tool according to the final deformation quantity. The dynamic influence that the surface deformation of the workbench is gradually increased along with time accumulation and the influence of the self weight of the workpiece on the surface of the workbench are reduced, and the overall machining performance of the five-axis numerical control machine tool is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of five-axis numerical control machining error detection, and particularly to a high-precision geometric error detection method and system for five-axis numerical control machining. Background Art

[0002] Five-axis numerical control machining technology has been widely applied in fields such as mold machining due to its high efficiency, flexibility, and precision. Five-axis CNC machine tools can simultaneously control the movement of five coordinate axes to achieve high-precision machining of complex curved surfaces and special-shaped parts. In order to meet the increasingly strict machining requirements and ensure the machining quality of parts, it is crucial to detect the high-precision deformation errors during the five-axis numerical control machining process.

[0003] In the field of five-axis CNC machining tool error detection, for the detection of the deformation error of the position of the workpiece on the workbench surface, the existing technology uses a laser interferometer to measure the deformation error of each measurement point on the workbench surface, and then calculates the deformation error of the workpiece position. However, this method has certain limitations in the implementation process: it fails to fully consider the dynamic characteristics of the deformation of the workbench surface gradually increasing with time accumulation and the influence of the workpiece's own weight on the workbench surface, resulting in a decrease in the accuracy of the deformation error detection, and further affecting the real-time performance and accuracy of subsequent compensation measures. Summary of the Invention

[0004] To solve the above problems, the present invention provides a high-precision geometric error detection method and system for five-axis numerical control machining.

[0005] The high-precision geometric error detection method and system for five-axis numerical control machining of the present invention adopt the following technical solutions: An embodiment of the present invention provides a high-precision geometric error detection method for five-axis numerical control machining, and the method includes the following steps: Measure the height error values of a number of preset measurement points along both sides of the support axis on the workbench surface of the five-axis CNC machining tool multiple times through a laser interferometer. The height error values of all measurement points for each measurement on the workbench surface form a height error matrix; For the height error matrix of the most recent measurement, obtain the symmetry axis corresponding to the support axis on the workbench surface in the height error matrix; obtain the distance between the position of the workpiece on the workbench surface at each moment and the support axis; by analyzing the difference changes between adjacent height error values on one side of the symmetry axis in each row of the height error matrix and the similarity of the height error values at symmetric positions on both sides of the symmetry axis in each row, determine the final possibility of deformation occurring in the corresponding area of the height error matrix on the workbench surface; By calculating the total difference in the change amounts of adjacent height error values between different rows in the height error matrix, the irregularity of the corresponding area of the height error matrix on the workbench surface is determined; by integrating the final possibility and the irregularity, the deformation amount of each measurement on the workbench surface is determined; according to the difference in the deformation amounts between the most recent measurement and the historical measurements on the workbench surface, the deformation rate of the most recent measurement on the workbench surface is determined. According to the deformation rate of the most recent measurement, the deformation amounts at each moment during the period from the most recent measurement to the next measurement on the workbench surface are predicted; according to the predicted deformation amounts and the distances of the positions of the workpiece at each moment from the support axis, the final deformation amounts at the positions of the workpiece on the workbench surface at each moment are determined; the five-axis CNC machine tool is compensated according to the final deformation amounts.

[0006] Further, the method for determining the final possibility of deformation in the corresponding area of the height error matrix on the workbench surface by analyzing the difference changes between adjacent height error values on one side of the symmetry axis in each row of the height error matrix and the similarity of the height error values at symmetric positions on both sides of the symmetry axis in each row includes the following specific steps: In the formula, is the number of height error values on the right side of the symmetry axis in the th row of the height error matrix; is the th height error value on the right side of the symmetry axis in the th row of the height error matrix; is the th height error value on the right side of the symmetry axis in the th row of the height error matrix; is the exponential function with the natural constant as the base; is the linear normalization function; is the initial possibility of deformation in the corresponding area of the workbench surface on the right side of the symmetry axis in the th row of the height error matrix; By analyzing the similarity of the height error values at symmetric positions on both sides of the symmetry axis in each row of the height error matrix, the credibility of deformation in the corresponding area of each row on the workbench surface is evaluated; By integrating the initial possibility and the credibility, the final possibility of deformation in the corresponding area of the height error matrix on the workbench surface is determined.

[0007] Further, the method for evaluating the credibility of deformation in the corresponding area of each row on the workbench surface by analyzing the similarity of the height error values at symmetric positions on both sides of the symmetry axis in each row of the height error matrix includes the following specific steps: In the formula, is the number of height error values on one side of the symmetry axis in the row of the height error matrix; is the row in the height error matrix, and the th height error value on the left side of the symmetry axis; represents taking the absolute value; is a preset hyperparameter; is the credibility of deformation occurring in the corresponding area of the workbench surface in the row of the height error matrix.

[0008] Furthermore, the specific steps for determining the final possibility of deformation occurring in the corresponding area of the workbench surface by integrating the initial possibility and credibility are as follows: In the formula, is the number of rows of the height error matrix; is the credibility of deformation occurring in the corresponding area of the workbench surface in the row of the height error matrix; is the final possibility of deformation occurring in the corresponding area of the workbench surface of the height error matrix.

[0009] Furthermore, the specific steps for determining the irregularity of the corresponding area of the workbench surface by calculating the sum of the differences in the change amounts of adjacent height error values between different rows in the height error matrix are as follows: In the formula, is the number of rows of the height error matrix; is the number of height error values contained in a single row of the height error matrix; is the absolute difference between the th and the th height error values in the row of the height error matrix; is the absolute difference between the th and the th height error values in the row of the height error matrix; represents taking the absolute value; is the irregularity of the corresponding area of the workbench surface of the height error matrix.

[0010] Furthermore, the specific steps for determining the deformation amount of each measurement on the workbench surface by integrating the final possibility and the irregularity are as follows: In the formula, is the final possibility of deformation occurring in the corresponding area on the workbench surface on the right side of the symmetry axis in the height error matrix; is the flatness of the corresponding area on the workbench surface in the height error matrix; is the amount of deformation of the workbench surface in the most recent measurement.

[0011] Further, determining the change rate of the amount of deformation of the workbench surface in the most recent measurement according to the difference between the amount of deformation of the most recent measurement and the historical measurements of the workbench surface includes the following specific steps: In the formula, is the preset number of historical measurements closest to the most recent measurement; is the fixed time interval between two adjacent measurements of the workbench surface; is the amount of deformation of the historical th measurement of the workbench surface closest to the most recent measurement; is the amount of deformation of the historical th measurement of the workbench surface closest to the most recent measurement; is to take the absolute value; is the change rate of the amount of deformation of the workbench surface in the most recent measurement.

[0012] Further, predicting the amount of deformation at each moment during the period from the most recent measurement to the next measurement of the workbench surface according to the change rate of the amount of deformation of the most recent measurement includes the following specific steps: In the formula, is the amount of deformation of the workbench surface in the most recent measurement; is the change rate of the amount of deformation of the workbench surface in the most recent measurement; is the th moment during the period from the most recent measurement to the next measurement of the workbench surface; is the fixed time interval between two adjacent measurements of the workbench surface; is the amount of deformation at the th moment during the period from the most recent measurement to the next measurement of the workbench surface.

[0013] Further, determining the final amount of deformation at the position of the workpiece on the workbench surface at each moment according to the predicted amount of deformation and the distance of the position of the workpiece at each moment from the support axis includes the following specific steps: In the formula, is the amount of deformation at the th moment during the period from the most recent measurement to the next measurement of the workbench surface; is the distance from the position of the workpiece on the workbench surface to the support shaft at the th moment; is the maximum distance from the measurement point on the workbench surface to the support shaft; is the final deformation amount of the position where the workpiece is located on the workbench surface at the th moment.

[0014] The present invention also provides a high-precision geometric error detection system for five-axis numerical control machining, including a memory and a processor. The processor executes the computer program stored in the memory to implement the steps of the foregoing method.

[0015] The beneficial effects of the technical solution of the present invention are as follows: According to the present invention, during the detection of the deformation error of the position where the workpiece is located on the workbench surface of a five-axis numerical control machine tool, the dynamic characteristics that the deformation of the workbench surface gradually worsens with time accumulation and the influence of the self-weight of the workpiece on the workbench surface can be fully considered. By analyzing the estimated deformation amount and the distance from the position of the workpiece on the workbench surface to the support shaft, the final deformation amount of the position where the workpiece is located on the workbench surface at each moment is determined, and then the five-axis numerical control machine tool is compensated according to the final deformation amount. When it is determined that the workbench surface is deformed, by analyzing the difference change between adjacent height error values on one side of the symmetry axis in each row of the height error matrix and the similarity of the height error values at symmetric positions on both sides of the symmetry axis in each row, the final possibility of the deformation of the corresponding area of the height error matrix on the workbench surface is determined, which improves the scientificity, accuracy and objectivity of the deformation analysis. When determining the estimated deformation amount, by analyzing the deformation rate of the workbench surface measured most recently, and then determining the estimated deformation amount at each time before the next measurement according to the deformation rate, the influence of the dynamic characteristics that the deformation of the workbench surface gradually worsens with time accumulation on the detection is reduced, which is beneficial to the improvement of the overall machining performance of the five-axis numerical control machine tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 is the flowchart of the steps of a high-precision geometric error detection method for five-axis numerical control machining provided by an embodiment of the present invention; Figure 2 is a schematic diagram of a five-axis numerical control machine tool provided by an embodiment of the present invention; Figure 3The basic schematic diagram of the measurement principle of the laser interferometer provided by an embodiment of the present invention; Figure 4 The schematic diagram of the scenario for measuring the height error value of the measurement points on the surface of the workbench of a five-axis CNC machine tool by a laser interferometer provided by an embodiment of the present invention; Figure 5 The schematic diagram of obtaining the height error matrix provided by an embodiment of the present invention. Specific embodiments

[0018] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following combines the drawings and preferred embodiments to detail the specific embodiments, structures, features and effects of a high-precision geometric error detection method and system for five-axis CNC machining proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0020] The following specifically describes the specific solution of a high-precision geometric error detection method and system for five-axis CNC machining provided by the present invention with reference to the drawings.

[0021] Please refer to Figure 1 , which shows the flowchart of the steps of a high-precision geometric error detection method for five-axis CNC machining provided by an embodiment of the present invention. The method includes the following steps: Step S001: Measure the height error values of a number of preset measurement points on both sides of the support axis on the surface of the workbench of the five-axis CNC machine tool multiple times by a laser interferometer. The height error values of all the measurement points measured each time on the workbench surface form a height error matrix.

[0022] It should be noted that the main purpose of this embodiment is to detect the final deformation amount of the workpiece at each moment on the surface of the workbench of the five-axis CNC machine tool. The final deformation amount reflects the geometric error of the five-axis CNC machine tool. Before starting the detection, first measure the height error values of a number of preset measurement points on both sides of the support axis on the surface of the workbench of the five-axis CNC machine tool multiple times by a laser interferometer for subsequent error detection and analysis.

[0023] It should be noted that this embodiment mainly analyzes the surface of the workbench of the X-axis of the five-axis CNC machine tool and a support axis under the workbench surface. Please refer to Figure 2 , Figure 2Schematic diagram of the five-axis CNC machine tool of this embodiment Figure 2 The five-axis CNC machine tool includes: X-axis: The spindle of the machine tool, moving along the horizontal direction, responsible for the radial cutting of the workpiece.

[0024] Y-axis: Perpendicular to the X-axis, usually moving on the horizontal plane, responsible for the transverse cutting of the workpiece.

[0025] Z-axis: Perpendicular to the X-axis and Y-axis, is the vertical axis of the machine tool, responsible for the depth cutting of the workpiece.

[0026] A-axis: A rotating axis, running the tool to rotate around the X-axis.

[0027] C-axis: The tool axis, allowing the tool or the workpiece to rotate around the Z-axis, facilitating the machining of various complex curved surfaces.

[0028] The platform similar to the long direction between the X-axis and the Y-axis is the workbench analyzed in this embodiment, and the two sliding force-bearing tracks parallel to the X-axis are the support axes analyzed in this embodiment. This embodiment mainly analyzes one of the force-bearing tracks, that is, one support axis. For the specific content of the sliding force-bearing track, please refer to Figure 4 the content in.

[0029] It should be further noted that in this embodiment, the height error values of several preset measurement points on both sides of the support axis of the workbench surface of the five-axis CNC machine tool are measured multiple times by a laser interferometer. The specific measurement principle is a well-known technology and will not be elaborated in this embodiment. Please refer to Figure 3 , Figure 3 is the basic schematic diagram of the measurement principle of the laser interferometer. Figure 3 It includes a laser head, an interferometer mirror and a reflector. The laser head is the light source of the laser interferometer, which emits a beam of monochromatic and highly coherent laser. This beam of laser is the basis for the operation of the interferometer; Interferometer mirror: The interferometer mirror is usually a beam splitter, which divides the laser beam into two beams, one beam is reflected and the other beam is transmitted, and these two beams of light propagate along different paths respectively; Reflector: The reflector is used to reflect the laser beam. In the interferometer, there are usually two reflectors, one is fixed and the other can move. The change in the position of the moving reflector will cause an optical path difference, thus generating an interference phenomenon. The laser interferometer has a high-precision acquisition effect and can measure and analyze a variety of geometric quantities and dynamic characteristics, that is, it can obtain the change data of the workbench surface height. Therefore, in this embodiment, the height error values of several preset measurement points on both sides of the support axis of the workbench surface of the five-axis CNC machine tool are measured multiple times by a laser interferometer.

[0030] It should be further noted that, please refer to Figure 4 , Figure 4This is a schematic diagram of the scenario where a laser interferometer is used to measure the height error values of the measurement points on the surface of the worktable of a five-axis CNC machine tool. Figure 4 The laser head, interferometer mirror, and reflector have been introduced in Figure 3 and will not be elaborated further. Among them, the laser head and the interferometer mirror are fixed, and the reflector is fixed on the surface of the worktable. In this embodiment, there are multiple reflectors. Figure 4 Only one reflector is shown in

[0031] . The multiple reflectors are in the same plane and parallel to the moving direction of the worktable. The position of each reflector is regarded as a measurement point. Subsequently, during the measurement, each measurement point has a height error value each time. The multiple reflectors are arranged at equal intervals. In this embodiment, the interval between adjacent reflectors is 15 mm, which can be adjusted according to the actual implementation situation, and this embodiment does not limit it. Specifically, the laser interferometer measures the height error values of several preset measurement points on both sides of the support axis on the surface of the worktable of the five-axis CNC machine tool multiple times. The height error values of all measurement points measured on the surface of the worktable each time form a height error matrix, which is specifically as follows:

[0032] It should be particularly noted that if the five-axis CNC machine tool is used for the first time, since the usage time of the machine tool is relatively short and the deformation degree is small, the data of the first 5 measurements are ignored in this embodiment, that is, the measurement data of the initial use of the machine tool is not analyzed.

[0033] It should be noted that please refer to Figure 5 . Figure 5Schematic diagram for obtaining the height error matrix in this embodiment Figure 5 It includes multiple measurement points, and each measurement point corresponds to a height error value. Furthermore, a height error matrix can be determined Figure 5 The dashed line in the middle is the support axis corresponding to the workbench. It should be particularly noted that in this embodiment, mainly an analysis of one support axis of the workbench is carried out, that is, only half of the workbench surface is analyzed. The analysis method for the other half of the workbench surface is the same, and the two parts are structurally symmetric

[0034] So far, by using a laser interferometer to measure the height error values of a number of preset measurement points on both sides of the support axis of the workbench surface of the five-axis CNC machine tool multiple times, the height error values of all measurement points measured each time on the workbench surface form a height error matrix

[0035] Step S002: For the height error matrix measured most recently, obtain the symmetry axis corresponding to the support axis of the workbench surface in the height error matrix; obtain the distance between the position of the workpiece on the workbench surface at each moment and the support axis; by analyzing the difference changes between adjacent height error values on one side of the symmetry axis in each row of the height error matrix and the similarity of the height error values at symmetric positions on both sides of the symmetry axis in each row, determine the final possibility of deformation in the corresponding area of the workbench surface for the height error matrix

[0036] It should be noted that for the convenience of subsequent analysis, first obtain the symmetry axis of the height error matrix based on the support axis of the workbench surface

[0037] Specifically, for the height error matrix measured most recently, obtain the symmetry axis corresponding to the support axis of the workbench surface in the height error matrix

[0038] It should be noted that all measurement points on the workbench surface can be regarded as a measurement point matrix, and the support axis of the workbench surface is located at the symmetry axis position of the measurement point matrix. For details, please refer to Figure 5 , Figure 5 The dashed line in the middle is the support axis corresponding to the workbench, that is, the symmetry axis position corresponding in the height error matrix

[0039] Furthermore, obtain the distance between the position of the workpiece on the workbench surface at each moment and the support axis

[0040] It should be noted that obtaining the distance between the position of the workpiece on the workbench surface at each moment and the support axis is an existing method, which will not be elaborated in this embodiment. Specifically, it can be determined by measuring the Euclidean distance from the centroid of the workpiece to the support axis

[0041] It should be noted that for the measurement points symmetric about both sides of the support shaft, the degree of deformation generally occurs similarly within the same time. Moreover, the deformation trend of the measurement points on the workbench surface far from the support shaft is larger, while the deformation trend of the measurement points close to the support shaft is smaller. The greater the deformation, the larger the height error value of the measurement point. Therefore, by analyzing the deformation changes of the measurement points on one side of the support shaft and the similarity of the deformation changes at the symmetric positions on both sides, the final possibility of deformation occurring in the corresponding area of the workbench surface for the height error matrix is determined, and the deformation changes are reflected by the height error value.

[0042] Specifically, by analyzing the difference changes between adjacent height error values on one side of the symmetry axis for each row in the height error matrix and the similarity of the height error values at the symmetric positions on both sides of the symmetry axis for each row, the final possibility of deformation occurring in the corresponding area of the workbench surface for the height error matrix is determined, and the steps included are as follows: First, by analyzing the difference changes between adjacent height error values on one side of the symmetry axis for each row in the height error matrix, the initial possibility of deformation occurring in the corresponding area of the workbench surface on one side of the symmetry axis for each row is evaluated.

[0043] Second, by analyzing the similarity of the height error values at the symmetric positions on both sides of the symmetry axis for each row in the height error matrix, the credibility of deformation occurring in the corresponding area of the workbench surface for each row is evaluated.

[0044] Finally, by synthesizing the initial possibility and the credibility, the final possibility of deformation occurring in the corresponding area of the workbench surface for the height error matrix is determined.

[0045] Specifically, by analyzing the difference changes between adjacent height error values on one side of the symmetry axis for each row in the height error matrix, the initial possibility of deformation occurring in the corresponding area of the workbench surface on one side of the symmetry axis for each row is evaluated as follows: In the formula, is the number of height error values on the right side of the symmetry axis for the th row in the height error matrix; is the th height error value on the right side of the symmetry axis for the th row in the height error matrix; is the th height error value on the right side of the symmetry axis for the th row in the height error matrix; is the exponential function with the natural constant as the base; is the linear normalization function for normalization processing; is the initial possibility of deformation occurring in the corresponding area of the workbench surface on the right side of the symmetry axis for the th row in the height error matrix.

[0046] It should be noted that The change trend of deformation between adjacent measurement points far from the support axis is represented by the difference between height error values. Since the deformation trend of the measurement points far from the support axis on the workbench surface is relatively large, if is larger, it indicates that the deformation trend of the measurement points far from the support axis is relatively large. This change trend of deformation is amplified by an exponential function, and the increasing trend of deformation occurring in the corresponding area on the workbench surface on the right side of the symmetry axis in the th row of the height error matrix is accumulated to obtain the initial possibility of deformation occurring in the corresponding area on the workbench surface on the right side of the symmetry axis in the th row. The larger it is, the greater the initial possibility of deformation.

[0047] Furthermore, by analyzing the similarity of the height error values at symmetric positions on both sides of the symmetry axis in each row of the height error matrix, the credibility of deformation occurring in the corresponding area of each row on the workbench surface is evaluated as follows: In the formula, is the number of height error values on one side of the symmetry axis in the th row of the height error matrix. It should be noted that the number of height error values on both sides of the symmetry axis in the height error matrix is equal; is the th height error value on the right side of the symmetry axis in the th row of the height error matrix; is the th height error value on the left side of the symmetry axis in the th row of the height error matrix; represents taking the absolute value; is a preset hyperparameter, the purpose of which is to prevent the denominator from being 0. In this embodiment, is used for description; is the credibility of deformation occurring in the corresponding area on the workbench surface in the th row of the height error matrix.

[0048] It should be noted that represents the similarity of the height error values of symmetric measurement points on both sides of the support axis on the workbench surface. For symmetric measurement points on both sides of the support axis, generally, the degree of deformation occurring in the same time is relatively similar. Therefore, is smaller, and the higher the credibility of deformation occurring in the corresponding area on the workbench surface in the th row of the height error matrix.

[0049] It should be noted that the above separately evaluates and analyzes the initial possibility of deformation occurring in the corresponding area on the workbench surface on one side of the symmetry axis for each row in the height error matrix, and the credibility of deformation occurring in the corresponding area on the workbench surface for each row. By combining these two indicators, the final possibility of deformation occurring in the corresponding area on the workbench surface for the height error matrix can be determined more accurately.

[0050] Furthermore, by combining the initial possibility and the credibility, the final possibility of deformation occurring in the corresponding area on the workbench surface for the height error matrix is determined as follows: In the formula, is the number of rows of the height error matrix; is the initial possibility of deformation occurring in the corresponding area on the workbench surface on the right side of the symmetry axis for the th row in the height error matrix; is the credibility of deformation occurring in the corresponding area on the workbench surface for the th row in the height error matrix; is the final possibility of deformation occurring in the corresponding area on the workbench surface for the height error matrix.

[0051] It should be noted that when the initial possibility of deformation occurring in the corresponding area on the workbench surface on the right side of the symmetry axis for the th row in the height error matrix is greater, and at the same time the credibility of deformation occurring in the corresponding area on the workbench surface for the th row in the height error matrix is higher, it indicates that the possibility of deformation occurring in the corresponding area on the workbench surface for the height error matrix is greater, that is, the final possibility is greater.

[0052] It should be particularly noted that in this embodiment, the initial possibility of deformation occurring in the corresponding area on the workbench surface on the right side of the symmetry axis for the th row in the height error matrix is used to replace the initial possibility of deformation occurring in the corresponding area on the workbench surface on both sides. When deformation occurs, the deformation conditions on both sides of the symmetry axis are similar.

[0053] Thus far, the final possibility of deformation occurring in the corresponding area on the workbench surface for the height error matrix is determined.

[0054] Step S003: By calculating the total difference in the change amount of adjacent height error values between different rows in the height error matrix, determine the irregularity of the corresponding area on the workbench surface for the height error matrix; by combining the final possibility and the irregularity, determine the deformation amount of each measurement on the workbench surface; according to the difference in the deformation amount between the most recent measurement and the historical measurement on the workbench surface, determine the deformation amount change rate of the most recent measurement on the workbench surface.

[0055] It should be noted that, generally, the distance from the measurement point along the support shaft to the support shaft is the same, and the change amount of the height error value between adjacent measurement points is also similar. If there is a large difference in the change amount of the height error value between adjacent measurement points along the support shaft, it indicates that the deformation of the workbench surface is irregular.

[0056] Specifically, by calculating the total difference in the change amount of adjacent height error values between different rows in the height error matrix, the irregularity degree of the corresponding area of the height error matrix on the workbench surface is determined, as follows: In the formula, is the number of rows of the height error matrix; is the number of height error values contained in a single row in the height error matrix; is the th height error value and the th height error value in the th row of the height error matrix, and the absolute difference between them; is the th height error value and the th height error value in the th row of the height error matrix, and the absolute difference between them;

[0057] It should be noted that represents the similarity of the change amount of the height error values between two adjacent columns of measurement points on the workbench surface parallel to the support shaft. If there is a large difference in the change amount of the height error values between adjacent measurement points along the support shaft, it indicates that the workbench surface is more irregular and the irregularity degree is greater.

[0058] It should be noted that the irregular deformation of the workbench surface is formed by a combination of various reasons. The deformation amount of the workbench surface in the current measurement can be obtained by combining the irregularity degree with the final possibility.

[0059] Furthermore, by combining the final possibility and the irregularity degree, the deformation amount of the workbench surface for each measurement is determined, as follows: In the formula, is the final possibility of deformation in the corresponding area of the workbench surface on the right side of the symmetry axis in the height error matrix; is the flatness of the corresponding area of the height error matrix on the workbench surface; is the deformation amount of the workbench surface in the most recent measurement.

[0060] It should be noted that the analysis process of the deformation amount of other measurements on the workbench surface is the same as that of the most recent measurement. The above analyzes the deformation amount of the most recent measurement on the workbench surface. Similarly, the deformation amounts of other measurements can also be obtained, and then the deformation amount of each measurement on the workbench surface can be determined. Details will not be repeated here.

[0061] Furthermore, according to the difference in the deformation amount between the most recent measurement and the historical measurements on the workbench surface, the deformation rate of the most recent measurement on the workbench surface is determined as follows: In the formula, is the preset number of historical measurements closest to the most recent measurement. In this embodiment, is used for illustration, where the number of historical measurements includes the most recent measurement; is the fixed time interval between two adjacent measurements on the workbench surface, with the unit of hour. In this embodiment, ; is the deformation amount of the th historical measurement closest to the most recent measurement on the workbench surface; is the deformation amount of the th historical measurement closest to the most recent measurement on the workbench surface; is to take the absolute value; is the deformation rate of the most recent measurement on the workbench surface.

[0062] It should be noted that by calculating the average change in the deformation amount of the historical 5 measurements, the deformation rate of the most recent measurement on the workbench surface is obtained, which can reflect the change in the deformation amount during the next measurement period. In this embodiment, it is assumed that after the most recent measurement, the deformation rate remains constant during the next measurement period.

[0063] Thus, the deformation rate of the most recent measurement on the workbench surface is determined.

[0064] Step S004: According to the deformation rate of the most recent measurement, estimate the deformation amounts of each moment from the most recent measurement to the next measurement on the workbench surface; according to the estimated deformation amounts and the distances of the workpiece at each moment from the support axis at the position where the workpiece is located on the workbench surface, determine the final deformation amounts at each moment at the position where the workpiece is located on the workbench surface; compensate the five-axis CNC machine tool according to the final deformation amounts.

[0065] It should be noted that the above determines the rate of change of the deformation amount of the most recent measurement of the workbench surface. Next, based on the rate of change of the deformation amount, the final deformation amount at any moment during the next measurement in the future is predicted. The final deformation amount reflects the geometric error of the five-axis CNC machine tool. Furthermore, according to the final deformation amount at each moment of the position of the workpiece on the workbench surface, the five-axis CNC machine tool is compensated.

[0066] Specifically, according to the rate of change of the deformation amount of the most recent measurement, the deformation amounts at each moment from the most recent measurement of the workbench surface to the next measurement are estimated as follows: In the formula, is the deformation amount of the most recent measurement of the workbench surface; is the rate of change of the deformation amount of the most recent measurement of the workbench surface; is the th moment from the most recent measurement of the workbench surface to the next measurement; is the fixed interval duration between two adjacent measurements of the workbench surface; is the deformation amount at the th moment from the most recent measurement of the workbench surface to the next measurement.

[0067] It should be noted that represents the increment of the deformation amount over time. When is larger, the increment of the deformation amount is larger, .

[0068] Furthermore, according to the estimated deformation amount and the distance from the position of the workpiece at each moment to the support axis, the final deformation amount at the position of the workpiece on the workbench surface at each moment is determined as follows: In the formula, is the deformation amount at the th moment from the most recent measurement of the workbench surface to the next measurement; is the distance from the position of the workpiece on the workbench surface to the support axis at the th moment; is the farthest distance from the measurement point on the workbench surface to the support axis; is the final deformation amount at the position of the workpiece on the workbench surface at the th moment.

[0069] It should be noted that the farther the position of the workpiece is from the support axis, the weaker the supporting effect of the support axis, and the larger the final deformation amount at the position of the workpiece, that is, is larger, and the final deformation amount at the position of the workpiece on the workbench surface at the The greater the final deformation amount at each moment, the final deformation amount reflects the geometric error of the five-axis CNC machine tool.

[0070] It should be noted that the above determines the final deformation amount of the position of the workpiece on the workbench surface at each moment. Next, according to the final deformation amount, the five-axis CNC machine tool is compensated.

[0071] Specifically, the five-axis CNC machine tool is compensated according to the final deformation amount.

[0072] It should be noted that compensating the five-axis CNC machine tool according to the final deformation amount of the position of the workpiece on the workbench surface at each moment is an existing method. Specifically, reference can be made to the content of the "Error Compensation Experiment" section on pages 136 to 137 of the article "Analysis and Compensation of Geometric Errors of Rotary Axes of Five-Axis Machine Tools" published by the authors Guo Shijie and Zhang Dongsheng in the journal "Engineering Science and Technology" in March 2020.

[0073] Through the above steps, a high-precision geometric error detection method for five-axis CNC machining is completed.

[0074] Another embodiment of the present invention provides a high-precision geometric error detection system for five-axis CNC machining. The system includes a memory and a processor. When the processor executes the computer program stored in the memory, the following operations are performed: Measure the height error values of several preset measurement points on both sides of the support axis of the workbench surface of the five-axis CNC machine tool multiple times through a laser interferometer. The height error values of all measurement points on the workbench surface each time measurement form a height error matrix; for the most recent measured height error matrix, obtain the symmetry axis corresponding to the support axis on the workbench surface in the height error matrix; obtain the distance between the position of the workpiece on the workbench surface at each moment and the support axis; by analyzing the difference changes between adjacent height error values on one side of the symmetry axis in each row of the height error matrix and the similarity of the height error values at symmetric positions on both sides of the symmetry axis in each row, determine the final possibility of deformation in the corresponding area of the workbench surface of the height error matrix; by calculating the total difference of the change amounts of adjacent height error values between different rows in the height error matrix, determine the irregularity of the corresponding area of the workbench surface of the height error matrix; comprehensively consider the final possibility and the irregularity to determine the deformation amount of each measurement on the workbench surface; according to the difference in the deformation amounts between the most recent measurement and the historical measurements of the workbench surface, determine the deformation rate of the most recent measurement on the workbench surface; according to the deformation rate of the most recent measurement, estimate the deformation amounts at each moment during the period from the most recent measurement on the workbench surface to the next measurement; according to the estimated deformation amounts and the distance between the position of the workpiece at each moment and the support axis, determine the final deformation amount of the position of the workpiece on the workbench surface at each moment; compensate the five-axis CNC machine tool according to the final deformation amount.

[0075] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high-precision geometric error detection method for five-axis numerical control machining, characterized in that The method includes the following steps: Measure the height error values of several preset measurement points on both sides of the support axis of the five-axis CNC machine tool workbench surface through a laser interferometer multiple times. The height error values of all measurement points for each measurement of the workbench surface form a height error matrix; For the height error matrix of the most recent measurement, obtain the symmetry axis corresponding to the support axis of the workbench surface in the height error matrix; obtain the distance between the position of the workpiece on the workbench surface at each moment and the support axis; by analyzing the difference changes between adjacent height error values on one side of the symmetry axis in each row of the height error matrix and the similarity of the height error values at symmetric positions on both sides of the symmetry axis in each row, determine the final possibility of deformation in the corresponding area of the workbench surface for the height error matrix; Determine the irregularity of the corresponding area of the workbench surface for the height error matrix by calculating the total difference in the change amounts of adjacent height error values between different rows in the height error matrix; combine the final possibility and the irregularity to determine the deformation amount of each measurement of the workbench surface; based on the difference in the deformation amounts between the most recent measurement and the historical measurements of the workbench surface, determine the deformation rate of the most recent measurement of the workbench surface; Estimate the deformation amounts at each moment during the period from the most recent measurement to the next measurement of the workbench surface according to the deformation rate of the most recent measurement; based on the estimated deformation amounts and the distances between the positions of the workpiece at each moment and the support axis, determine the final deformation amounts at the positions of the workpiece on the workbench surface at each moment; compensate the five-axis CNC machine tool according to the final deformation amounts.

2. The high-precision geometric error detection method for five-axis numerical control machining according to claim 1, wherein The step of determining the final possibility of deformation in the corresponding area of the workbench surface for the height error matrix by analyzing the difference changes between adjacent height error values on one side of the symmetry axis in each row of the height error matrix and the similarity of the height error values at symmetric positions on both sides of the symmetry axis in each row includes the following specific steps: In the formula, is the number of height error values on the right side of the symmetry axis in the th row of the height error matrix; is the th height error value on the right side of the symmetry axis in the th row of the height error matrix; is the th height error value on the right side of the symmetry axis in the th row of the height error matrix; is the exponential function with the natural constant as the base; is the linear normalization function; is the initial possibility of deformation occurring in the corresponding area on the workbench surface on the right side of the symmetry axis in the th row of the height error matrix; Evaluate the credibility of deformation in the corresponding area of the workbench surface for each row by analyzing the similarity of the height error values at symmetric positions on both sides of the symmetry axis in each row of the height error matrix; Combine the initial possibility and the credibility to determine the final possibility of deformation in the corresponding area of the workbench surface for the height error matrix.

3. The high-precision geometric error detection method for five-axis numerical control machining according to claim 2, wherein The step of evaluating the credibility of deformation in the corresponding area of the workbench surface for each row by analyzing the similarity of the height error values at symmetric positions on both sides of the symmetry axis in each row of the height error matrix includes the following specific steps: Wherein, is the number of height error values on one side of the symmetry axis in the th row of the height error matrix; is the th height error value on the left side of the symmetry axis in the th row of the height error matrix; represents taking the absolute value; is a preset hyperparameter; is the credibility of deformation occurring in the corresponding area on the workbench surface in the th row of the height error matrix.

4. A high-precision geometric error detection method for five-axis numerical control machining according to claim 2, characterized in that, The step of combining the initial possibility and the credibility to determine the final possibility of deformation in the corresponding area of the workbench surface for the height error matrix includes the following specific steps: In the formula, is the number of rows of the height error matrix; is the credibility of the deformation occurring in the corresponding area on the workbench surface for the -th row in the height error matrix; is the final possibility of the deformation occurring in the corresponding area on the workbench surface for the height error matrix.

5. A high-precision geometric error detection method for five-axis numerical control machining according to claim 1, characterized in that, The step of determining the irregularity of the corresponding area of the workbench surface for the height error matrix by calculating the total difference in the change amounts of adjacent height error values between different rows in the height error matrix includes the following specific steps: In the formula, is the number of rows of the height error matrix; is the number of height error values contained in a single row in the height error matrix; is the th row in the height error matrix, the th height error value and the th height error value of the absolute difference; is the th row in the height error matrix, the th height error value and the th height error value of the absolute difference; is to take the absolute value; is the irregularity of the corresponding area of the height error matrix on the workbench surface.

6. The high-precision geometric error detection method for five-axis numerical control machining according to claim 1, wherein The step of combining the final possibility and the irregularity to determine the deformation amount of each measurement of the workbench surface includes the following specific steps: In the formula, is the final possibility of deformation occurring in the corresponding area on the workbench surface on the right side of the symmetry axis in the height error matrix; is the flatness of the corresponding area of the height error matrix on the workbench surface; is the amount of deformation measured most recently on the workbench surface.

7. A high-precision geometric error detection method for five-axis numerical control machining according to claim 1, characterized in that, The step of determining the deformation rate of the most recent measurement of the workbench surface based on the difference in the deformation amounts between the most recent measurement and the historical measurements of the workbench surface includes the following specific steps: Wherein, is the preset number of historical measurements closest to the most recent measurement; is the fixed time interval between two adjacent measurements on the workbench surface; is the deformation amount of the th historical measurement closest to the most recent measurement on the workbench surface; is the deformation amount of the th historical measurement closest to the most recent measurement on the workbench surface; represents taking the absolute value; is the change rate of the deformation amount of the most recent measurement on the workbench surface.

8. A high-precision geometric error detection method for five-axis numerical control machining according to claim 1, characterized in that, Predicting the deformation amount at each moment during the period from the most recent measurement to the next measurement based on the change rate of the deformation amount measured most recently, including the following specific steps: Wherein, is the deformation of the workbench surface measured most recently; is the change rate of the deformation of the workbench surface measured most recently; is the th moment during the period from the most recent measurement to the next measurement of the workbench surface; is the fixed interval duration between two adjacent measurements of the workbench surface; is the deformation of the workbench surface at the th moment during the period from the most recent measurement to the next measurement of the workbench surface.

9. The high-precision geometric error detection method for five-axis numerical control machining according to claim 1, characterized in that Determining the final deformation amount at the position of the workpiece on the workbench surface at each moment based on the predicted deformation amount and the distance from the position of the workpiece at each moment to the support shaft, including the following specific steps: Wherein, is the deformation amount of the workbench surface during the period from the most recent measurement to the next measurement at the th moment; is the distance from the position of the workpiece on the workbench surface to the support shaft at the th moment; is the maximum distance from the measurement point on the workbench surface to the support shaft; is the final deformation amount of the position where the workpiece is located on the workbench surface at the th moment.

10. A high-precision geometric error detection system for five-axis numerical control machining, the system comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the computer program is executed by a processor, it implements the steps of a high-precision geometric error detection method for five-axis numerical control machining according to any one of claims 1-9.

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