Geometric error detection device and method for rotating shaft of machine tool of rttr type

Abstract

The application relates to a detection device and a detection method for the geometric error of a rotating shaft of an RTTTR type machine tool, the detection device comprising a base, an X-direction sliding table, a Y-direction sliding table, a Z-direction sliding table, a rotary table and three grating scales; the grating scales are respectively installed on the Z-direction sliding table, the X-direction sliding table and the Y-direction sliding table, the axes of the grating scales intersect with the axes of the Z-direction sliding table, the X-direction sliding table and the Y-direction sliding table in space and are perpendicular to each other; the axes of the grating scales are respectively parallel to the displacement directions of X-direction sliding rails, Y-direction sliding rails and Z-direction sliding rails of the machine tool; reading heads of the grating scales are respectively installed on the X-direction sliding table, the Y-direction sliding table and the Z-direction sliding table; the Z-direction sliding table, the X-direction sliding table and the Y-direction sliding table respectively measure the spatial position coordinates of displacement of a workpiece ball of a ball bar along the Z-axis, the X-axis and the Y-axis directions, and are used for calculating the geometric error of a B-axis rotating shaft of the machine tool; the technical scheme has higher measurement precision and meets the requirement of rapid measurement.

Description

Technical Field

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

[0002] With the increasing demand for precision components in industries such as aerospace, precision instruments, shipbuilding, and intelligent robotics, machine tools, as the carriers of precision component processing, have received considerable attention. Research on improving the geometric accuracy of CNC machine tools is crucial, as precision machining tools can achieve higher processing precision. However, their requirements for environmental and other factors are relatively stringent. Among these, geometric errors, thermal errors, and servo drive errors have a major impact on the processing accuracy of precision machine tools. Geometric errors account for approximately 20% of all errors, therefore, compensating for machine tool geometric errors is of great significance for improving machine tool processing performance. Limited by manufacturing capabilities, machine tool geometric errors are mainly generated during the processing and assembly of various components. Simultaneously, mechanical wear caused by the machine tool's motion processing also leads to geometric errors, which are unavoidable in all stages of machine tool manufacturing and processing. Given their repetitive nature, geometric errors can be eliminated through measurement and compensation methods. Compared to methods that reduce the introduction of geometric errors by improving machine tool manufacturing and assembly processes, geometric error measurement and compensation methods are cost-effective and easy to implement.

[0003] In existing technologies, one geometric error measurement scheme identifies ten position-related geometric errors on two rotating axes by selecting five measurement trajectories, and identifies eight position-independent geometric errors on the two rotating axes of the machine tool by simplifying the ballbar's placement. However, this technique cannot identify geometric errors related to rotation around itself, and requires frequent disassembly and reassembly of the ballbar during measurement, introducing positioning errors. Other technologies have studied the placement of the ballbar and the errors of the rotating axes, proposing a step-by-step measurement scheme to separately measure position-independent and position-related errors of the rotating axes; however, the entire measurement process requires cumbersome and numerous ballbar positioning error calibration steps. Although some technologies identify the geometric errors of the rotating axes by coupling the rotation of the two axes and measuring the offset of the entire motion space with the ballbar, this method requires a large amount of measurement data. The six-line method identifies geometric errors by setting measurement paths at different positions on the rotating axes, but this method requires setting three different positions on the rotating axes, and each measurement path must be in the sensitive direction of the ballbar measurement.

[0004] The aforementioned research primarily focuses on identifying the geometric errors of the rotary axes in machine tools with dual rotary tables and rotary table-swivel-head couplings. Significant positional errors exist when recording the spatial coordinates of the ballbar, which reduces the accuracy of the ten geometric errors identified in the machine tool's rotary axes. Due to limitations in machine tool dimensions and the structure of measuring instruments, it is difficult to employ a universal method to measure the geometric errors of rotary axes for machine tools with different structures. Since RTTTR type precision machine tools are widely used in the production and processing of precision products, it is necessary to improve the measurement of the geometric errors of the rotary axes in dual rotary table separation type (RTTTR type) machine tools. Specifically, existing identification methods mostly only identify partial geometric error data and require measurements at multiple positions on the rotary axis to establish an error identification model, resulting in lengthy measurement times. Furthermore, the repeated disassembly and reassembly of the ballbar can introduce installation errors in the measuring instrument, leading to high unreliability of the identification results. Therefore, an improved detection device for the geometric errors of the rotary axes of RTTTR type machine tools is proposed. Summary of the Invention

[0005] To address one of the aforementioned shortcomings, this application provides a detection device and method for detecting the geometric error of the rotary axis of an RTTTR type machine tool, thereby improving detection accuracy.

[0006] An RTTTR type machine tool rotary axis geometric error detection device includes: a base, an X-axis sliding stage, a Y-axis sliding stage, a Z-axis sliding stage, a turntable, and three grating rulers;

[0007] The grating ruler is respectively installed on the Z-axis sliding table, X-axis sliding table, and Y-axis sliding table. The axes of the grating ruler and the Z-axis sliding table, X-axis sliding table, and Y-axis sliding table intersect each other in space and are perpendicular to each other. The axes of the grating ruler are parallel to the displacement directions of the X-axis sliding guide, Y-axis sliding guide, and Z-axis sliding guide of the machine tool, respectively.

[0008] The reading heads of the grating ruler are respectively installed on the X-axis sliding stage, the Y-axis sliding stage, and the Z-axis sliding platform;

[0009] The rotary table is fixed on the Z-axis sliding guide rail of the machine tool, the tool holder is fixed on the machine tool spindle, and the tool ball and workpiece ball of the ball bar are respectively installed on the tool holder and the base;

[0010] The Z-axis sliding stage, X-axis sliding stage, and Y-axis sliding stage respectively measure the spatial position coordinates of the workpiece ball displacement along the Z-axis, X-axis, and Y-axis directions of the ball bar, which are used to input the geometric error of the B-axis of the computer machine tool spindle into the computer.

[0011] In one embodiment, the computer is used to design a set of measurement trajectories for the ballbar based on the kinematic model of the relative motion of the machine tool spindle and the geometric error measurement mechanism of the ballbar. The computer sequentially controls the ballbar to move according to each measurement trajectory in the set of measurement trajectories. The computer calculates the geometric error of the B-axis of the machine tool spindle by inputting the spatial position coordinates of the workpiece ball's displacement along the Z-axis, X-axis, and Y-axis directions through the feedback signal of the grating ruler. The set of measurement trajectories includes multiple trajectories with preset measurement point positions.

[0012] In one embodiment, the preset measurement trajectory includes measurement trajectory 1, measurement trajectory 2, ..., measurement trajectory 10; wherein, in measurement trajectory 1, the spatial vector between the two balls of the ballbar passes through the origin of the coordinate axis; in measurement trajectory 2, the ballbar is located at the origin of the turntable, such that the spatial vector between the tool ball and the workpiece ball is perpendicular to the machine tool table and parallel to the Y-axis of the machine tool; measurement trajectories 3-10 are non-fixed position trajectories placed at two different positions in the machine tool space, and each measurement trajectory position includes the symmetrically distributed spatial vector positions of the tool ball and the workpiece ball at different positions.

[0013] In one embodiment, the geometric errors include four position-independent geometric errors of the machine tool spindle B-axis and six position-dependent geometric errors of the machine tool spindle B-axis.

[0014] In one embodiment, the computer is used to perform error correction on the spatial position coordinates of the workpiece ball of the ball bar instrument along the Z-axis, X-axis, and Y-axis directions of the selected target measurement trajectory according to the error adjustment values ​​of each measurement trajectory output by the error calculation model, and to calculate the geometric error of the B-axis of the computer tool spindle according to the corrected spatial position coordinates.

[0015] The error calculation model is used to characterize the range of different spatial positions in the machine tool space and the corresponding introduced error.

[0016] In one embodiment, the computer obtains corresponding error sub-data based on the geometric errors calculated from the geometric errors of each set of the ballbar instrument according to multiple sets of measurement trajectories, and performs comprehensive calculations based on the error sub-data to obtain the geometric error of the machine tool spindle B axis.

[0017] A method for detecting geometric errors of the rotary axis of an RTTTR type machine tool, applied to the detection equipment for geometric errors of the rotary axis of the RTTTR type machine tool, comprising:

[0018] (1) Move the X-axis sliding table, Y-axis sliding table and Z-axis sliding table to obtain the spatial position coordinates of the workpiece ball of the ball bar on the machine tool motion platform;

[0019] (2) Control the B-axis of the machine tool to rotate and obtain the relative position deviation value between the workpiece ball and the tool ball of the ball bar during the rotation process;

[0020] (3) Measure the error data of the machine tool spindle B axis according to the preset measurement trajectory, and obtain the geometric error of the machine tool spindle B axis according to the error data.

[0021] In one embodiment, step (3) includes:

[0022] Based on the kinematic model of the relative motion of the machine tool spindle and the geometric error measurement mechanism of the ballbar, the error data of the B-axis of the machine tool spindle is measured using a preset measurement trajectory;

[0023] The geometric error of the B-axis of the machine tool is calculated based on the error data of the machine tool spindle at the corresponding position using the ballbar and an optimized search algorithm.

[0024] In one embodiment, the method for calculating the four position-independent geometric errors of the machine tool spindle B-axis includes:

[0025]

[0026]

[0027]

[0028] Where R is the length of the ballbar 02, and ΔR is the reading of the ballbar 02;

[0029]

[0030]

[0031]

[0032]

[0033] In the formula, [E XB E ZB S xB S zB ] represents four position-independent geometric errors of the machine tool spindle B-axis.

[0034] In one embodiment, the method for calculating the six position-related geometric errors of the machine tool spindle B-axis includes:

[0035]

[0036] Where, Φ T It is the set objective function value, Φ act This is the actual measured value from the ballbar (02), Φcal It is based on the estimated value of the ballbar (02), β i P is the angle of rotation of the machine tool spindle B-axis (09). j D k These represent the position and orientation of the workpiece ball on the base, respectively. [E X (β) E Y (β) E Z (β) E A (β) E B (β) E C [β] represents the six position-related geometric errors of the machine tool spindle B-axis.

[0037] A computer device comprising:

[0038] One or more processors;

[0039] Memory;

[0040] One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the one or more processors, the one or more applications being configured to perform the steps of the above-described method for detecting the geometric error of the rotary axis of an RTTTR type machine tool.

[0041] A computer-readable storage medium storing at least one instruction, at least one program, code set, or instruction set, wherein the at least one instruction, the at least one program, the code set, or the instruction set is loaded by a processor and the processor executes the steps of the above-described method for detecting geometric errors of the rotary axis of an RTTTR type machine tool.

[0042] The technical solutions of the above embodiments have the following technical effects:

[0043] Using a grating ruler as the measuring device, it offers high measurement accuracy, can precisely measure geometric errors, and boasts higher measurement precision and a wide measurement bandwidth. It can quickly measure the displacement of the workpiece ball along the X, Y, and Z axes of the ballbar, and rapidly calculate the geometric error data of the turntable, thus facilitating rapid measurement and meeting the needs of high-speed measurement.

[0044] Additional aspects and advantages of this application will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0045] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0046] Figure 1This is a schematic diagram of the structure of a detection device for the geometric error of the rotary axis of an RTTTR type machine tool, according to one embodiment.

[0047] Figure 2 This is a partial enlarged view of an example RTTTR type machine tool rotary axis geometric error detection device;

[0048] Figure 3 This is a schematic diagram of the measurement principle of an example ballbar;

[0049] Figure 4 This is a schematic diagram illustrating an example of calculating geometric errors using corrected spatial position coordinates;

[0050] Figure 5 This is a flowchart of a method for detecting geometric errors of the rotary axis of an RTTTR type machine tool, according to one embodiment.

[0051] Figure 6 This is a comparison chart of the identification results as an example. Detailed Implementation

[0052] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0053] Those skilled in the art will understand that, unless otherwise stated, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the word “comprising” as used in this application’s specification means the presence of the stated feature, integer, step, or operation, but does not preclude the presence or addition of one or more other features, integers, steps, or operations.

[0054] A three-dimensional coordinate system is established based on the machine tool space, corresponding to the X-axis, Y-axis, and Z-axis directions, with the machine tool worktable plane being the XY plane. In the rotary axis geometric error detection scheme for a dual-rotary-table (RTTTR type) machine tool, the detection scheme includes the following formula ①:

[0055]

[0056] In the formula, [D x D y D z ]、[P x P y P z [E] represents the measurement direction and position of the ballbar 02 on the turntable 07, respectively. X (β) E Y (β) EZ (β) E A (β) E B (β) E C [β] represents the six position-related geometric errors of the machine tool spindle B-axis, [E XB E ZB S xB S zB The four position-independent geometric errors of the machine tool spindle B-axis are represented, totaling ten geometric errors. By using a ballbar 02 to measure the comprehensive error and obtain the spatial coordinates of the measurement points, the ten geometric error parameters of the machine tool spindle motion can be solved.

[0057] In the above matrix, if there is a large positional error when recording the spatial position coordinates of the ballbar 02, the accuracy of the ten geometric errors of the machine tool spindle B axis 09 will be reduced. Only some geometric error data can be identified, and it is necessary to measure at multiple positions of the rotating axis to establish an error identification model. The measurement is time-consuming, and the multiple disassembly and installation of the ballbar 02 can also easily introduce measurement instrument installation errors, resulting in insufficient accuracy of the detection results.

[0058] Based on this, this application proposes a detection device and method for the geometric error of the rotary axis of an RTTTR type machine tool, with reference to... Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of an RTTTR type machine tool rotary axis geometric error detection device according to an embodiment, including: a base 03, an X-axis sliding stage 05, a Y-axis sliding stage 06, a Z-axis sliding stage 04, a turntable 07, and three grating rulers 08; wherein, the three grating rulers 08 are respectively mounted on the Z-axis sliding stage 04, the X-axis sliding stage 05, and the Y-axis sliding stage 06, and the axes of the grating rulers 08 and the Z-axis sliding stage 04, the X-axis sliding stage 05, and the Y-axis sliding stage 06 intersect each other in space and are perpendicular to each other; the axes of the grating rulers 08 are parallel to the displacement directions of the X-axis sliding guide rail 11, the Y-axis sliding guide rail 12, and the Z-axis sliding guide rail 10 of the machine tool.

[0059] refer to Figure 2 As shown, Figure 2 This is a partial enlarged view of an example RTTTR type machine tool rotary axis geometric error detection device; the reading head of the grating ruler 08 is respectively mounted on the X-axis sliding table 05, Y-axis sliding table 06 and Z-axis sliding table 04; the rotary table 07 is fixed on the Z-axis sliding table 04 of the machine tool, the tool holder fixture 01 is fixed on the machine tool spindle 13, and the tool ball 2b and workpiece ball 2a of the ball bar 02 are respectively mounted on the tool holder fixture 01 and the base 03.

[0060] During the inspection, the Z-axis sliding stage 04, X-axis sliding stage 05, and Y-axis sliding stage 06 respectively measure the spatial position coordinates of the workpiece ball 2a of the ball bar instrument 02 along the Z-axis, X-axis, and Y-axis directions. These spatial position coordinates are then input into the computer 14 to measure the geometric error of the computer machine tool spindle B-axis 09.

[0061] For example, such as Figure 3 As shown, Figure 3 This is a schematic diagram of the measurement principle of a ballbar. First, the X-axis sliding stage 05, Y-axis sliding stage 06, and Z-axis sliding stage 04 are moved. The spatial position coordinates of the workpiece ball 2a of the ballbar 02, i.e., the spatial coordinates of the measurement point, are obtained through the feedback signal of the grating ruler 08. Then, the B-axis 09 of the machine tool is controlled to rotate. By obtaining the relative position deviation value between the workpiece ball 2a and the tool ball 2b of the ballbar 02, the geometric error of the B-axis 09 of the machine tool is measured according to each measurement trajectory in the preset measurement trajectory set, and the geometric error of the B-axis 09 of the machine tool is identified.

[0062] In one embodiment, when calculating geometric error, the computer 14 designs a set of measurement trajectories for the ballbar 02 based on the kinematic model of the relative motion of the machine tool spindle and the geometric error measurement mechanism of the ballbar 02. The set of measurement trajectories includes multiple trajectories with preset measurement point positions. Then, the ballbar 02 is controlled to move sequentially according to each measurement trajectory in the set of measurement trajectories. The spatial position coordinates of the workpiece ball 2a of the ballbar 02 along the Z-axis, X-axis and Y-axis directions can be obtained through the feedback signal of the grating ruler (08). The geometric error of the machine tool spindle B-axis 09 is calculated using these spatial position coordinates.

[0063] The measurement trajectory refers to the spatial linkage measurement trajectory. When designing the measurement trajectory, it can be set according to the actual application requirements. Generally, eight measurement trajectories can be used to achieve the measurement purpose. In actual applications, the appropriate trajectory can be selected according to the requirements.

[0064] In one embodiment, to achieve more accurate measurement results, this application designs a set of 10 measurement trajectories, including measurement trajectory 1, measurement trajectory 2, ..., measurement trajectory 10; wherein, in measurement trajectory 1, the spatial vector between the two balls of the ballbar passes through the origin of the coordinate axis. In measurement trajectory 2, the ballbar 02 is located at the origin of the turntable 07, such that the spatial vector between the tool ball 2b and the workpiece ball 2a is perpendicular to the machine tool table and parallel to the Y-axis of the machine tool. Measurement trajectories 3-10 adopt non-fixed position trajectories, which can include measurement points placed at two different positions in the machine tool space. Each measurement trajectory position includes the symmetrically distributed spatial vector positions of the tool ball 2b and the workpiece ball 2a at different positions, thereby forming 8 sets of symmetrically distributed measurement point positions with higher spatial coverage.

[0065] As described in the above embodiment, by designing a set of 10 measurement trajectories, the measurement points cover the spatial vector passing through the origin of the coordinate axis, the origin of the turntable, and multiple sets of symmetrically distributed spatial vector positions, thereby improving the accuracy of the measurement position data.

[0066] In one embodiment, the computer 14 is used to calculate four position-independent geometric errors of the machine tool spindle B-axis and six position-dependent geometric errors of the machine tool spindle B-axis.

[0067] As described in the above embodiments, the technical solution overcomes the shortcomings of RTTTR type machine tools and measurement processes in detecting geometric errors of single-axis motion of machine tools, which cannot adapt to a large number of adjustments to the position of the ball bar 02 workpiece ball 2a, thus introducing positional errors of the ball bar 02. By using a grating ruler 08 to quickly measure the displacement of the ball bar 02 along the X-axis, Y-axis, and Z-axis, the technical effect of quickly measuring and recording the spatial position of the ball bar 02 is achieved. This allows for accurate acquisition of the spatial position of each measurement point. By using the grating ruler 08 as the measuring element, the geometric error data of the turntable 07 can be quickly calculated on the computer 14 using a specific algorithm. This results in higher measurement accuracy and a wide measurement bandwidth, with a short measurement time, meeting the requirements for rapid measurement.

[0068] To make the technical effects of this application clearer, more embodiments are described below.

[0069] In one embodiment, as the relative relationship between the ballbar 02 and the grating ruler 08 changes in different spatial positions, the feedback signal from the grating ruler 08 will introduce errors. These errors are related to the position of the measurement point on the measurement trajectory. Accordingly, when the computer 14 detects the geometric error of the computer bed spindle B-axis 09, it may further include the following:

[0070] Step A1: Adjust the error values ​​of each measurement trajectory output by the error calculation model; whereby the error calculation model is used to characterize the range of different spatial positions in the machine tool space and the corresponding introduced error.

[0071] For example, by establishing quantified error values ​​introduced at different spatial locations throughout the entire machine tool space as error adjustment values ​​introduced at each measurement point, the error adjustment value is calculated and output based on the error calculation model when measuring the spatial coordinate position of each measurement point in each measurement trajectory.

[0072] For the error calculation model, it can be obtained by statistically analyzing the actual measurement data in the measurement and then performing overfit quantization to obtain the error calculation model that can calculate the error adjustment value.

[0073] Step A2: Correct the spatial position coordinates of the workpiece ball (2a) of the ball bar instrument 02 of the selected target measurement trajectory along the Z-axis, X-axis and Y-axis directions according to the error adjustment value; for each spatial position coordinate, use its corresponding error adjustment value for correction.

[0074] Step A3: Calculate the geometric error of the B-axis 09 of the computer tool spindle based on the corrected spatial position coordinates; specifically, for each measurement trajectory, more accurate spatial position data can be obtained through the corrected spatial position data of each measurement point.

[0075] like Figure 4 As shown, Figure 4 This is an example of calculating geometric error using corrected spatial position coordinates, assuming the measurement trajectory L obtained by the grating ruler 08 is... i Measurement point p j The spatial coordinates of P ij (x, y, z), for the measurement trajectory L i Measurement point p j The measurement point p output by the error calculation model j The error adjustment value is △p ij (△x, △y, △z), then △p ij Using decorrection P ij Then it is used for the geometric error of the B-axis 09 of the computer tool spindle, where i represents the measurement trajectory number and j represents the measurement point number.

[0076] As described in the above embodiment, the error adjustment value is used to adjust the spatial position coordinates measured by the grating ruler 08 at each measurement point in the measurement trajectory, and then used for the geometric error of the computer tool spindle B axis 09. This can improve the accuracy of the geometric error calculation results and greatly enhance the geometric error identification accuracy.

[0077] In one embodiment, in order to further improve the identification accuracy of geometric errors, when the computer 14 calculates the geometric error of the machine tool spindle B axis 09, it can further obtain corresponding error sub-data based on the geometric error calculated from the multiple measurement trajectory sets of the ballbar instrument 02, and perform comprehensive calculation based on the error sub-data to obtain the geometric error of the machine tool spindle B axis 09.

[0078] Specifically, suppose k sets of measurement trajectories are designed, each set containing multiple measurement trajectories, and the corresponding error sub-data E1, E2, ... E1 are calculated for each set of measurement trajectories. k The geometric error obtained from the comprehensive calculation can be expressed by the following formula:

[0079]

[0080] In the formula, E represents the geometric error, and k represents the set number of the measurement trajectory.

[0081] As described in the above embodiments, the geometric error of the machine tool spindle B-axis 09 is calculated by using multiple sets of measurement trajectories. This can improve the accuracy of the calculation results, reduce the influence of discrete values, and thus improve the identification accuracy of the geometric error.

[0082] This application also provides a method for detecting the geometric error of the rotary axis of an RTTTR type machine tool, applied to the aforementioned detection equipment for the geometric error of the rotary axis of an RTTTR type machine tool, with reference to... Figure 5 As shown, Figure 5 This is a flowchart of a method for detecting the geometric error of the rotary axis of an RTTTR type machine tool, including the following steps:

[0083] (1) Move the X-axis sliding table 05, the Y-axis sliding table 06, and the Z-axis sliding table 04 to obtain the spatial position coordinates of the workpiece ball 2a on the machine tool motion platform of the ball bar instrument 02.

[0084] Specifically, during the test, the X-axis sliding stage 05, Y-axis sliding stage 06, and Z-axis sliding stage 04 are moved first. The spatial position coordinates of the workpiece ball 2a of the ball bar instrument 02, i.e., the spatial coordinates of the measurement point, are obtained through the feedback signal of the grating ruler 08.

[0085] (2) Control the B axis 09 of the machine tool to rotate, and obtain the relative position deviation value between the workpiece ball 2a and the tool ball 2b of the ball bar instrument 02 during the rotation process.

[0086] (3) Measure the error data of machine tool spindle B axis 09 according to the preset measurement trajectory, and obtain the geometric error of machine tool spindle B axis 09 according to the error data.

[0087] In one embodiment, step (3) may specifically include the following:

[0088] Based on the kinematic model of the relative motion of the machine tool spindle and the geometric error measurement mechanism of the ballbar 02, the error data of the machine tool spindle B-axis 09 is measured using a preset measurement trajectory; the geometric error of the machine tool spindle B-axis 09 is calculated by combining the error data of the machine tool spindle at the corresponding position of the ballbar 02 with an optimized search algorithm.

[0089] In one embodiment, the calculation method for the four position-independent geometric errors of the machine tool spindle B is shown in formula ②:

[0090] For example, it can be adopted Figure 4 The following formula can be obtained from measurement trajectories 1 and 3 using the least squares method:

[0091]

[0092]

[0093]

[0094] Where R is the length of the ballbar 02, and ΔR is the reading of the ballbar 02;

[0095]

[0096]

[0097]

[0098]

[0099] In the formula, [E XB E ZB S xB S zB ] represents four position-independent geometric errors of the machine tool spindle B-axis.

[0100] In one embodiment, the calculation method for the six position-related geometric errors of the machine tool spindle B-axis is shown in formula ③:

[0101] For example, it can be adopted Figure 4 Measurement trajectories 2 and 4-10 are used to set the objective function:

[0102]

[0103] Where, Φ T It is the set objective function value, Φ act This is the actual measured value of the ballbar instrument 02, Φ cal This is based on the estimated value from cue stick 02, which can be calculated using formula ①, β i P represents the rotation angle of the machine tool spindle B-axis 09. j D k Given the position and orientation of workpiece ball 2a on base 03 of ballbar 02, and using a particle swarm optimization algorithm, six position-related geometric error values ​​[E] of the machine tool spindle B-axis can be calculated. X (β)E Y (β)E Z (β)E A (β)E B (β)E C (β)].

[0104] As described in the above embodiments, the scheme can identify the positional error data by placing a small amount of data and reduce the space placement and calibration process of the ball bar 02, resulting in more accurate identification results and greatly reducing the impact of actual positional errors on the solution results.

[0105] Based on the solutions of the above embodiments, the technical solution of this application uses a grating ruler 08 as a measuring device, which has high measurement accuracy and can quickly measure the displacement of the workpiece ball 2a along the X, Y, and Z axes of the ball bar 02; through an optimized search algorithm, the geometric error data of the turntable 07 can be quickly calculated on the computer 14. To further clarify the beneficial effects of the technical solution of this application, refer to... Figure 6 As shown, Figure 6 The figure shows a comparison of identification results. As can be seen from the comparison of the results of shaft compensation between the technical solution of this application and the traditional geometric error identification method, the technical solution of this application has a smaller deviation between the identified geometric error and the actual measurement value, and the compensation effect is better.

[0106] This application also provides a computer device, which includes:

[0107] One or more processors;

[0108] Memory;

[0109] One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the one or more processors, the one or more applications being configured to perform the steps of the above-described method for detecting the geometric error of the rotary axis of an RTTTR type machine tool.

[0110] For example, the computer device may be a mobile phone, computer, digital broadcasting terminal, messaging device, game console, tablet device, medical device, fitness device, personal digital assistant, etc.

[0111] This application also provides a computer-readable storage medium storing at least one instruction, at least one program, code set, or instruction set, wherein the at least one instruction, the at least one program, the code set, or the instruction set is loaded by the processor and the processor executes the steps of the above-described method for detecting the geometric error of the rotary axis of an RTTTR type machine tool.

[0112] For example, the computer-readable storage medium can be a non-transitory computer-readable storage medium that includes instructions, such as a memory that includes instructions. For example, a non-transitory computer-readable storage medium can be a ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device, etc.

[0113] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A detection device for the geometric error of the rotary axis of an RTTTR type machine tool, characterized in that, include: Base (03), X-axis sliding stage (05), Y-axis sliding stage (06), Z-axis sliding stage (04), turntable (07) and three grating rulers (08); The grating ruler (08) is installed on the Z-axis sliding stage (04), X-axis sliding stage (05), and Y-axis sliding stage (06) respectively. The axes of the grating ruler (08) and the Z-axis sliding stage (04), X-axis sliding stage (05), and Y-axis sliding stage (06) intersect each other in space and are perpendicular to each other. The axis of the grating ruler (08) is parallel to the displacement direction of the X-axis sliding guide (11), Y-axis sliding guide (12), and Z-axis sliding guide (10) of the machine tool respectively. The reading heads of the grating ruler (08) are respectively installed on the X-axis sliding stage (05), the Y-axis sliding stage (06) and the Z-axis sliding stage (04); The turntable (07) is fixed on the Z-axis sliding guide rail (10) of the machine tool, the tool holder fixture (01) is fixed on the machine tool spindle (13), and the tool ball (2b) and workpiece ball (2a) of the ball bar (02) are respectively installed on the tool holder fixture (01) and the base (03); The Z-axis sliding stage (04), X-axis sliding stage (05), and Y-axis sliding stage (06) respectively measure the spatial position coordinates of the workpiece ball (2a) of the ball bar instrument (02) along the Z-axis, X-axis, and Y-axis directions, and are used to input the geometric error of the computer bed spindle B-axis (09) in the computer (14); The computer (14) is used to design a set of measurement trajectories for the ballbar (02) based on the kinematic model of the relative motion of the machine tool axis and the geometric error measurement mechanism of the ballbar (02). The computer controls the ballbar (02) to move according to each measurement trajectory in the set of measurement trajectories. The computer inputs the spatial position coordinates of the displacement of the workpiece ball (2a) of the ballbar (02) along the Z-axis, X-axis and Y-axis directions through the feedback signal of the grating ruler (08) to calculate the geometric error of the machine tool axis B-axis (09). The set of measurement trajectories includes multiple trajectories with preset measurement point positions. The set of measurement trajectories includes 10 measurement trajectories; in the first measurement trajectory, the ballbar is the space vector between the two balls passing through the origin of the coordinate axis; in the second measurement trajectory, the ballbar (02) is located at the origin of the turntable (07), so that the space vector between the tool ball (2b) and the workpiece ball (2a) is perpendicular to the machine tool table and parallel to the Y-axis of the machine tool; the remaining 8 measurement trajectories are non-fixed position trajectories placed at two different positions in the machine tool space, and each measurement trajectory position includes the symmetrically distributed space vector positions of the tool ball (2b) and the workpiece ball (2a) at different positions; The geometric errors include four position-independent geometric errors of the machine tool spindle B-axis and six position-dependent geometric errors of the machine tool spindle B-axis. The computer (14) is used to perform error correction on the spatial position coordinates of the workpiece ball (2a) of the ball bar (02) of the selected target measurement trajectory along the Z-axis, X-axis and Y-axis directions according to the error adjustment value of each measurement trajectory output by the error calculation model, and to calculate the geometric error of the computer tool spindle B axis (09) according to the corrected spatial position coordinates. The error calculation model is used to characterize the range of different spatial positions in the machine tool space and the corresponding introduced error.

2. A method for detecting geometric errors of the rotary axis of an RTTTR type machine tool, characterized in that, The detection device for the geometric error of the rotary axis of the RTTTR type machine tool as described in claim 1 includes: (1) Move the X-axis sliding table (05), Y-axis sliding table (06), and Z-axis sliding table (04) to obtain the spatial coordinates of the workpiece ball (2a) on the machine tool motion platform of the ball bar (02); (2) Control the B axis (09) of the machine tool to rotate, and obtain the relative position deviation value of the workpiece ball (2a) and the tool ball (2b) of the ball bar instrument (02) during the rotation process; (3) Measure the error data of the machine tool spindle B axis (09) according to the preset measurement trajectory, and obtain the geometric error of the machine tool spindle B axis (09) according to the error data.

3. The method for detecting geometric errors of the rotary axis of an RTTTR type machine tool according to claim 2, characterized in that, Step (3) includes: Based on the kinematic model of the relative motion of the machine tool shaft and the geometric error measurement mechanism of the ballbar (02), the error data of the machine tool shaft B axis (09) is measured using a preset measurement trajectory; The geometric error of the machine tool spindle B axis (09) is calculated based on the error data of the machine tool spindle at the corresponding position of the ballbar (02) and the optimization search algorithm.

4. The method for detecting geometric errors of the rotary axis of an RTTTR type machine tool according to claim 3, characterized in that, The calculation method for the four position-independent geometric errors of the machine tool spindle B-axis includes: ； ； ； Where R is the length of the lever (02), It is the reading from the ballbar (02); ； ； ； ； In the formula, These are four position-independent geometric errors of the machine tool spindle.

5. The method for detecting geometric errors of the rotary axis of an RTTTR type machine tool according to claim 4, characterized in that, The calculation method for the six position-related geometric errors of the machine tool spindle B-axis includes: ； in, It is the set objective function value. This is the actual measurement value from the ballbar (02). It is based on the estimated value of the cue stick (02). The angle of rotation of the machine tool spindle B-axis (09) The positions and orientations of the workpiece ball (2a) on the base (03) are respectively those of the ballbar (02). These are six position-related geometric errors of the machine tool spindle.

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