A machine tool geometric error detection device and a rapid measurement method

Abstract

The present application belongs to the field of machine tool error precision measurement, and discloses a machine tool geometric error detection device and a rapid measurement method. In view of the problems of existing instruments and methods, such as multiple installations, low efficiency, and easy to be disturbed by environment, the machine tool geometric error detection supports multiple rod synchronous installation and rapid disassembly through the spindle end multi-interface spherical hinge tooling and the base end magnetic attraction structure, and realizes multiple error synchronous measurement at one time. In view of eccentricity and zero point error in assembly, the error parameter decoupling calibration method based on linearization measurement equation and least square is adopted to obtain the base station position and parameters. Further, through the multi-rod collaborative measurement and pseudo base station compensation mechanism, the machine tool positioning error, straightness error and perpendicularity error are solved synchronously in single closed trajectory operation. The present application realizes efficient and reliable evaluation of assembly error calibration compensation and machine tool space error, and is suitable for rapid measurement of numerical control machine tool geometric error.

Description

Technical Field

[0001] This invention belongs to the field of precision measurement technology and relates to a machine tool geometric error detection device and a rapid measurement method. Background Technology

[0002] Machine tool accuracy is a key factor affecting its machining capabilities. Improving machine tool accuracy can be achieved through two main methods: increasing mechanical precision, which is limited by the manufacturing precision of the machine tool hardware and is costly; and error compensation, a more efficient and cost-effective approach that is widely used for improving machine tool accuracy. Achieving error compensation requires detecting geometric errors. Traditional geometric error detection instruments suffer from low measurement efficiency and difficulty in guaranteeing accuracy. For example, laser interferometers have complex installation devices, time-consuming optical path adjustments, and their detection accuracy is greatly affected by the environment; the measurement accuracy of laser trackers depends on the calibration accuracy of the optical base station. Therefore, there is an urgent need to invent a machine tool geometric error detection device and calibration measurement method to achieve rapid and accurate acquisition of machine tool geometric errors.

[0003] Currently, domestic research has been conducted on machine tool spatial error detection devices. In 2016, Guo Junjie et al. from Xi'an Jiaotong University disclosed a measuring device and method for measuring the geometric error of the translational axis of a CNC machine tool in patent CN103447884B. This method uses a laser tracker to measure the axial feed motion of a single translational axis of the machine tool at three fixed points at four different positions. In 2021, Wu Shi et al. from Harbin University of Science and Technology disclosed an in-machine detection device for the geometric error of a five-axis machine tool rotary axis in patent CN113587870A. This device identifies various geometric errors of the rotary axis through contact measurements with a standard ball and a standard S-shaped specimen. Also in 2021, Sun Tao et al. from Hangzhou Dianzi University disclosed a three-dimensional error measuring device for a multi-axis machine tool spindle based on a ballbar in patent CN213090624U. This device can measure spatial errors perpendicular to the measurement plane that cannot be obtained by existing ballbars. In 2024, Jiang Zhong et al. from the Institute of Mechanical Manufacturing Technology, China Academy of Engineering Physics, disclosed a five-axis machine tool linkage error detection device and calculation method in patent CN112405112B. The device can detect the spatial displacement error of the machine tool tool and simultaneously measure the tool motion posture and tool tip position error in real time.

[0004] Through research and analysis of existing machine tool geometric error detection devices and calibration measurement methods, it was found that: (1) the repeated installation of optical equipment in multi-base station measurement methods is cumbersome and time-consuming, which limits the improvement of measurement efficiency; (2) the measurement accuracy of measurement devices based on traditional measuring instruments may still be affected by environmental factors in the processing workshop; (3) existing measurement devices lack effective error calibration methods. Summary of the Invention

[0005] The purpose of this invention is to address the problems of complex installation, reliance on fixed optical base stations, and insufficient measurement efficiency in existing machine tool geometric error measurement devices, and to propose a machine tool geometric error detection device and calibration measurement method. Through simplified structure, convenient installation, calibrable error measurement, and high-efficiency measurement, this invention enables rapid and accurate detection of geometric errors in the linear axes of machine tools.

[0006] The technical solution of this invention:

[0007] A machine tool geometric error detection device includes a multi-interface ball joint fixture 1 at the spindle end, a magnetic suction fixture 2 at the base end, a data processing unit 3, and a laser interferometry unit 4.

[0008] The multi-interface ball joint fixture 1 is installed on the spindle end of the machine tool and is equipped with multiple ball socket interfaces for simultaneously fixing multiple laser interferometry units 4 to achieve synchronous clamping and repeated positioning.

[0009] The base end magnetic suction fixture 2 includes a bottom magnetic suction fixing unit 21 and an upper precision ball socket 22. The upper precision ball socket 22 is detachably engaged with the standard ball 41 at the end of the laser interferometry unit 4 to form a ball joint pair, realizing clamping and disassembly; and the bottom magnetic suction fixing unit 21 is used to fix the machine tool geometric error detection device on the machine tool worktable.

[0010] The data processing unit 3 is used to receive the length readings from the laser interferometry unit 4, perform error calibration, fake base station compensation, and machine tool error calculation on the acquired length readings, and output error data and verification results.

[0011] The laser interferometry unit 4 includes a standard sphere 41, a telescopic rod 42, a laser measurement module 43, a support structure 44, and a standard sphere clamping plate 45. The laser measurement module 43 is installed inside the telescopic rod 42. The support structure 44 is installed at one end of the telescopic rod 42 and connected to a standard sphere 41. The standard sphere clamping plate 45 is installed at the other end of the telescopic rod 42 and connected to another standard sphere 41. The endpoint coordinates of the standard spheres 41 at both ends of the laser interferometry unit 4 are the endpoint coordinates of the measurement end point, respectively. coordinates of the base station endpoint Measure the coordinates of the end points and base station endpoint coordinates The true geometric distance is:

[0012]

[0013] The interferometer length reading output by laser measurement module 43 is Considering zero-point offset Installation Deviation Items Establish the measurement equation:

[0014]

[0015] Among them, installation deviation item The zero-point offset is determined by the installation position and angular deviation of the laser interferometry unit 4. The zero-point dead zone and initial bias of the laser interferometry unit 4 are used to correct the error; the correspondence between these two and the actual installation error of the laser interferometry unit 4 is as follows:

[0016]

[0017]

[0018] in, , The installation deviation of the laser interferometry unit 4. , , For the angular installation deviation of laser interferometry unit 4, This is the zero-point offset of the laser interferometry unit 4.

[0019] A method for rapid measurement of machine tool geometric errors, based on the aforementioned machine tool geometric error detection device, includes the following error parameter calibration steps:

[0020] Step 1: Installation and Data Acquisition;

[0021] One end of the laser interferometry unit 4 is rigidly fixed to the ball-and-socket interface at the end of the multi-interface ball joint fixture 1 at the spindle end via a standard ball 41, and the coordinates of the theoretically measured end point are collected. And read the interferometer length reading output by the laser measurement module 43. The standard sphere 41 at the other end of the laser interferometry unit 4 is fixed at the predetermined base station position as the base station endpoint coordinate by the upper precision ball socket 22 of the magnetic suction fixture 2 at the base end. ;

[0022] Step 2: Establish the measurement equation;

[0023] The measurement equation is established based on laser interferometry unit 4:

[0024]

[0025] Step 3: Linearization processing;

[0026] Introducing intermediate variables The measurement equation is linearized into a linearized equation:

[0027]

[0028] Step 4: Solve using least squares;

[0029] By changing the spatial pose of the measurement end point, at least five sets of coordinates of the theoretical measurement end point at different positions are collected. Interferometer length reading Substitute each set of data into the linearized equation to form an overdetermined system of equations, and use the least squares method to solve for the coordinates of the base station endpoints. Zero offset and installation deviation items .

[0030] Furthermore, collaborative measurement using multiple laser interferometry units is achieved, with the following steps:

[0031] Step 1: Install multiple poles;

[0032] At least four calibrated laser interferometry units 4 are simultaneously fixed at one end to different interfaces on the end face of the machine tool spindle via a multi-interface ball joint fixture 1 at the spindle end, locking the spindle to prevent rotation; the other end of each laser interferometry unit 4 is fixed to the machine tool worktable via a magnetic suction fixture 2 at the base end, forming multiple measurement links, with each measurement point having a constant offset from the end face of the machine tool spindle. ;

[0033] Step 2: Introduction of fake base stations;

[0034] To absorb the offset of the multi-interface ball joint fixture 1 at the spindle end, the location of the fake base station is defined as follows:

[0035]

[0036] Step 3: Solve the linearized equations for the base station;

[0037] Introducing intermediate variables Then consider the location of the fake base station. The measurement equation can be linearized into a linear equation:

[0038]

[0039] Step 4: Simultaneous solution;

[0040] The linear equations of step 3 are formed by the synchronous readings of multiple laser interferometry units 4, an overdetermined system of equations is constructed, and the location of the fake base station is solved using the least squares method. ;

[0041] Step 5: Solve the linearized equations at the end positions;

[0042] Introducing intermediate variables Then the measurement equation can be linearized into a linear equation:

[0043]

[0044] Step 6: Use the synchronous readings from multiple laser interferometry units 4 to form the linear equation from Step 5, and finally solve for the coordinates of the measurement end point. And no additional offset calibration is required during the process. ;

[0045] The fake base station location compensation can absorb the offset of the multi-interface ball joint tooling 1 at the spindle end. The influence on the measurement equation should be considered to avoid biasing the multi-interface ball joint tooling 1 at the spindle end. Perform individual measurements and calibrations to achieve the coordinates of the measurement endpoints. The calculation.

[0046] A rapid measurement method for machine tool geometric errors, comprising the following steps for measuring the straightness and perpendicularity errors of a machine tool:

[0047] Step 1: Trajectory execution;

[0048] The machine tool's running trajectory is set, and the machine tool is controlled to run according to a preset sequence XYZ, XZY, YXZ, YZX, ZXY or ZYX, and return to the starting point along the diagonal to form a closed trajectory; during operation, the machine tool spindle is kept locked, the magnetic suction fixture 2 at the base end is fixed and the optical path is aligned with the laser interferometry unit 4; X, Y, and Z represent the machine tool's running direction, which is the same as the machine tool's X, Y, and Z linear axis directions;

[0049] Step 2: Trajectory point measurement;

[0050] The coordinates of discrete trajectory points at the ends of n laser interferometry units 4, obtained by collaborative measurement using multiple laser interferometry units:

[0051] ,

[0052] and the coordinates of its corresponding theoretical trajectory points. Pairing, the coordinates of the theoretical trajectory points are obtained based on the machine tool running trajectory set in step 1;

[0053] Step 3: Calculate straightness error;

[0054] The straightness error is calculated based on the coordinates of the discrete trajectory points at the end of the laser interferometry unit 4 and the coordinates of the theoretical trajectory points:

[0055]

[0056] in, It refers to the straightness error of the machine tool in the X direction. It refers to the straightness error of the machine tool in the Y direction. It is the straightness error of the machine tool in the Z direction;

[0057] Step 4: Calculate the verticality deviation;

[0058] The direction vectors of each axis are obtained by fitting the discrete trajectory. Calculate the perpendicularity deviation between axes:

[0059]

[0060] Among them, i=x, y, z, j=x, y, z, Let X, Y, and Z be the direction vectors of the linear axes.

[0061] Step 5: Cross-validation;

[0062] The error distribution of the trajectory returning to the starting point along the diagonal in step 1 was used to compare and verify the linear axis measurement results.

[0063] The beneficial effects of this invention are:

[0064] (1) The magnetic tooling fixing method is adopted to avoid the cumbersome operation of traditional clamping installation, realize the rapid installation and high repeatability positioning of the device on the machine tool, and improve the efficiency of on-site operation.

[0065] (2) A calibration and decoupling procedure for the error of the laser interferometric measurement unit is proposed, which can simultaneously correct the installation offset and zero-point error, thereby improving the accuracy and reliability of the measurement results;

[0066] (3) By using multiple laser interferometric measurement units to coordinate the measurement steps, the machine tool position can be solved in real time. Compared with the traditional method that requires repeated measurement, the measurement efficiency is significantly improved, and the use of fake base station compensation avoids additional tooling offset calibration.

[0067] (4) A rapid measurement scheme based on closed trajectory is proposed, which can efficiently obtain the linear axis error and can also be cross-validated through trajectory consistency, thereby enhancing the credibility of the results. Attached Figure Description

[0068] Figure 1 This is a schematic diagram of the collaborative measurement installation of a machine tool spatial error detection device.

[0069] Figure 2 This is a flowchart of the error calibration and measurement process.

[0070] Figure 3 This is an isometric drawing of a machine tool spatial error detection device.

[0071] Figure 4 This is a schematic diagram of a machine tool spatial error detection device.

[0072] Figure 5This is a diagram of the internal structure of a laser interferometry unit.

[0073] Figure 6 This is a schematic diagram illustrating the error analysis principle of a laser interferometry unit. Figure 7 The diagram shows the principle of the collaborative measurement trajectory of the machine tool spatial error detection device; where (a) is the trajectory diagram of XYZ, ZYX, and YZX, and (b) is the trajectory diagram of XZY, ZXY, and YXZ.

[0074] Figure 8 The results of the straightness error calculation of the machine tool in the X, Y, and Z directions are shown in the example.

[0075] In the figure: 1. Multi-interface ball joint fixture at the spindle end; 2. Magnetic suction fixture at the base end; 3. Data processing unit; 4. Laser interferometry unit; 21. Bottom magnetic fixing unit; 22. Upper precision ball socket; 41. Standard ball; 42. Telescopic rod; 43. Laser measurement module; 44. Support structure; 45. Standard ball clamp. Detailed Implementation

[0076] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0077] like Figure 1 As shown, the present invention provides a machine tool geometric error detection device, including a multi-interface ball joint fixture 1 at the spindle end, a magnetic suction fixture 2 at the base end, a data processing unit 3, and a laser interferometry unit 4.

[0078] In this embodiment, a machine tool geometric error detection device includes a multi-interface ball joint fixture 1 at the spindle end, a magnetic suction fixture 2 at the base end, a data processing unit 3, and a laser interferometry unit 4.

[0079] The multi-interface ball joint fixture 1 is installed on the spindle end of the machine tool and is equipped with multiple ball socket interfaces for simultaneously fixing multiple laser interferometry units 4 to achieve synchronous clamping and repeated positioning.

[0080] The base end magnetic suction fixture 2 includes a bottom magnetic suction fixing unit 21 and an upper precision ball socket 22. The upper precision ball socket 22 is detachably engaged with the standard ball 41 at the end of the laser interferometry unit 4 to form a ball joint pair, realizing clamping and disassembly; and the bottom magnetic suction fixing unit 21 is used to fix the machine tool geometric error detection device on the machine tool worktable.

[0081] The data processing unit 3 is used to receive the length readings from the laser interferometry unit 4, perform error calibration, fake base station compensation, and machine tool error calculation on the acquired length readings, and output error data and verification results.

[0082] The laser interferometry unit 4 includes a standard sphere 41, a telescopic rod 42, a laser measurement module 43, a support structure 44, and a standard sphere clamping plate 45. The laser measurement module 43 is installed inside the telescopic rod 42. The support structure 44 is installed at one end of the telescopic rod 42 and connected to a standard sphere 41. The standard sphere clamping plate 45 is installed at the other end of the telescopic rod 42 and connected to another standard sphere 41. The endpoint coordinates of the standard spheres 41 at both ends of the laser interferometry unit 4 are the endpoint coordinates of the measurement end point, respectively. coordinates of the base station endpoint Measure the coordinates of the end points and base station endpoint coordinates The true geometric distance is:

[0083]

[0084] The interferometer length reading output by laser measurement module 43 is Considering zero-point offset Installation Deviation Items Establish the measurement equation:

[0085]

[0086] Among them, installation deviation item The zero-point offset is determined by the installation position and angular deviation of the laser interferometry unit 4. The zero-point dead zone and initial bias of the laser interferometry unit 4 are used to correct the error; the correspondence between these two and the actual installation error of the laser interferometry unit 4 is as follows:

[0087]

[0088]

[0089] in, , The installation deviation of the laser interferometry unit 4. , , For the angular installation deviation of laser interferometry unit 4, This is the zero-point offset of the laser interferometry unit 4.

[0090] In this embodiment, as Figure 2 As shown, the machine tool geometric error detection device described above includes the following error parameter calibration steps:

[0091] Step 1: Installation and Data Acquisition;

[0092] One end of the laser interferometry unit 4 is rigidly fixed to the ball-and-socket interface at the end of the multi-interface ball joint fixture 1 at the spindle end via a standard ball 41, and the coordinates of the theoretically measured end point are collected. And read the interferometer length reading output by the laser measurement module 43. The standard sphere 41 at the other end of the laser interferometry unit 4 is fixed at the predetermined base station position as the base station endpoint coordinate by the upper precision ball socket 22 of the magnetic suction fixture 2 at the base end. ;

[0093] Step 2: Establish the measurement equation;

[0094] The measurement equation is established based on laser interferometry unit 4:

[0095]

[0096] Step 3: Linearization processing;

[0097] Introducing intermediate variables The measurement equation is linearized into a linearized equation:

[0098]

[0099] Step 4: Solve using least squares;

[0100] By changing the spatial pose of the measurement end point, at least five sets of coordinates of the theoretical measurement end point at different positions are collected. Interferometer length reading Substitute each set of data into the linearized equation to form an overdetermined system of equations, and use the least squares method to solve for the coordinates of the base station endpoints. Zero offset and installation deviation items Based on the calculation results, the zero-point offset is... and installation deviation items Used for subsequent measurement corrections to achieve decoupled compensation for installation deviations and zero-point errors.

[0101] In this embodiment, the multi-laser interferometry unit collaborative measurement provided by the present invention proceeds as follows:

[0102] Step 1: Install multiple poles;

[0103] like Figure 1 , Figure 3 and Figure 4As shown, at least four calibrated laser interferometry units 4 are simultaneously fixed at one end to different interfaces on the end face of the machine tool spindle via a multi-interface ball joint fixture 1 at the spindle end, locking the spindle to prevent rotation; the other end of each laser interferometry unit 4 is fixed to the machine tool worktable via a magnetic suction fixture 2 at the base end, forming multiple measurement links, with each measurement point having a constant offset from the end face of the machine tool spindle. ;

[0104] Step 2: Introduction of fake base stations;

[0105] To absorb the offset of the multi-interface ball joint fixture 1 at the spindle end, the location of the fake base station is defined as follows:

[0106]

[0107] Step 3: Solve the linearized equations for the base station;

[0108] Introducing intermediate variables Then consider the location of the fake base station. The measurement equation can be linearized into a linear equation:

[0109]

[0110] Step 4: Simultaneous solution;

[0111] The linear equations of step 3 are formed by the synchronous readings of multiple laser interferometry units 4, an overdetermined system of equations is constructed, and the location of the fake base station is solved using the least squares method. ;

[0112] Step 5: Solve the linearized equations at the end positions;

[0113] Introducing intermediate variables Then the measurement equation can be linearized into a linear equation:

[0114]

[0115] Step 6: Use the synchronous readings from multiple laser interferometry units 4 to form the linear equation from Step 5, and finally solve for the coordinates of the measurement end point. And no additional offset calibration is required during the process. ;

[0116] The fake base station location compensation can absorb the offset of the multi-interface ball joint tooling 1 at the spindle end. The influence on the measurement equation should be considered to avoid biasing the multi-interface ball joint tooling 1 at the spindle end. Perform individual measurements and calibrations to achieve the coordinates of the measurement endpoints. The calculation.

[0117] In this embodiment,

[0118] A rapid measurement method for machine tool geometric errors, comprising the following steps for measuring the straightness and perpendicularity errors of a machine tool:

[0119] Step 1: Trajectory execution;

[0120] The machine tool's running trajectory is set, and the machine tool is controlled to run according to a preset sequence XYZ, XZY, YXZ, YZX, ZXY or ZYX, and return to the starting point along the diagonal to form a closed trajectory; during operation, the machine tool spindle is kept locked, the magnetic suction fixture 2 at the base end is fixed and the optical path of the laser interferometry unit 4 is aligned; X, Y, and Z represent the machine tool's running direction, which is the same as the X, Y, and Z linear axis direction of the machine tool;

[0121] Step 2: Trajectory point measurement;

[0122] The coordinates of discrete trajectory points at the ends of n laser interferometry units 4, obtained by collaborative measurement using multiple laser interferometry units:

[0123] ,

[0124] and the coordinates of its corresponding theoretical trajectory points. Pairing, the coordinates of the theoretical trajectory points are obtained based on the machine tool running trajectory set in step 1;

[0125] Step 3: Calculate straightness error;

[0126] The straightness error is calculated based on the coordinates of the discrete trajectory points at the end of the laser interferometry unit 4 and the coordinates of the theoretical trajectory points:

[0127]

[0128] in, It refers to the straightness error of the machine tool in the X direction. It refers to the straightness error of the machine tool in the Y direction. It is the straightness error of the machine tool in the Z direction;

[0129] Step 4: Calculate the verticality deviation;

[0130] The direction vectors of each axis are obtained by fitting the discrete trajectory. Calculate the perpendicularity deviation between axes:

[0131]

[0132] Among them, i=x, y, z, j=x, y, z, Let X, Y, and Z be the direction vectors of the linear axes.

[0133] Step 5: Cross-validation;

[0134] The error distribution of the trajectory returning to the starting point along the diagonal in step 1 was used to compare and verify the linear axis measurement results.

Claims

1. A machine tool geometric error detection device, characterized in that, The machine tool geometric error detection device includes a multi-interface ball joint fixture (1) at the spindle end, a magnetic suction fixture (2) at the base end, a data processing unit (3) and a laser interferometry unit (4). The multi-port ball joint fixture (1) is installed on the spindle end of the machine tool and is equipped with multiple ball sockets for simultaneously fixing multiple laser interferometric measurement units (4) to achieve synchronous clamping and repeated positioning. The base end magnetic suction fixture (2) includes a bottom magnetic suction fixing unit (21) and an upper precision ball socket (22). The upper precision ball socket (22) is detachably engaged with the standard ball (41) at the end of the laser interferometry unit (4) to form a ball joint pair, thereby realizing clamping and disassembly. The bottom magnetic suction fixing unit (21) is used to fix the machine tool geometric error detection device on the machine tool workbench. The data processing unit (3) is used to receive the length reading of the laser interferometric measurement unit (4), perform error calibration, fake base station compensation and machine tool error calculation on the collected length reading, and output error data and verification results; The laser interferometry unit (4) includes a standard sphere (41), a telescopic rod (42), a laser measurement module (43), a support structure (44), and a standard sphere clamping plate (45). The laser measurement module (43) is installed inside the telescopic rod (42). The support structure (44) is installed at one end of the telescopic rod (42) and connected to a standard sphere (41). The standard sphere clamping plate (45) is installed at the other end of the telescopic rod (42) and connected to another standard sphere (41). The endpoint coordinates of the standard spheres (41) at both ends of the laser interferometry unit (4) are the endpoint coordinates of the measurement end point, respectively. coordinates of the base station endpoint Measure the coordinates of the end points and base station endpoint coordinates The true geometric distance is: The interferometer length reading output by the laser measurement module (43) is: Considering zero-point offset Installation Deviation Items Establish the measurement equation: Among them, installation deviation item The zero-point offset is determined by the installation position and angular deviation of the laser interferometry unit (4). The zero-point dead zone and initial bias of the laser interferometric measurement unit (4) are used to correct the actual installation error of the laser interferometric measurement unit (4). in, , For the positional installation deviation of the laser interferometry unit (4), , , For the angular installation deviation of the laser interferometry unit (4), The zero-point offset of the laser interferometric measurement unit (4) is given.

2. A method for rapid measurement of machine tool geometric errors, characterized in that, This rapid measurement method for machine tool geometric errors is based on the machine tool geometric error detection device described in claim 1, and includes the following error parameter calibration steps: Step 1: Installation and Data Acquisition; One end of the laser interferometry unit (4) is rigidly fixed to the ball-and-socket interface at the end of the multi-interface ball joint fixture (1) at the spindle end via a standard ball (41), and the coordinates of the theoretically measured end point are collected. And read the interferometer length reading output by the laser measurement module (43). The standard ball (41) at the other end of the laser interferometry unit (4) is fixed at the predetermined base station position as the base station endpoint coordinate by the upper precision ball socket (22) of the magnetic suction fixture (2) at the base end. ; Step 2: Establish the measurement equation; The measurement equation is established based on the laser interferometric measurement unit (4): Step 3: Linearization processing; Introducing intermediate variables The measurement equation is linearized into a linearized equation: Step 4: Solve using least squares; By changing the spatial pose of the measurement end point, at least five sets of coordinates of the theoretical measurement end point at different positions are collected. Interferometer length reading Substitute each set of data into the linearized equation to form an overdetermined system of equations, and use the least squares method to solve for the coordinates of the base station endpoints. Zero offset and installation deviation items .

3. The method for rapid measurement of machine tool geometric errors according to claim 2, characterized in that, The steps for collaborative measurement using multiple laser interferometry units are as follows: Step 1: Install multiple poles; At least four calibrated laser interferometry units (4) are simultaneously fixed at one end to different interfaces on the end face of the machine tool spindle via a multi-interface ball joint fixture (1) at the spindle end, locking the spindle to prevent rotation; the other end of each laser interferometry unit (4) is fixed to the machine tool worktable via a magnetic suction fixture (2) at the base end, forming multiple measurement links, with each measurement point having a constant offset from the end face of the machine tool spindle. ; Step 2: Introduction of fake base stations; To absorb the offset of the multi-interface ball joint fixture (1) at the spindle end, the position of the fake base station is defined as follows: Step 3: Solve the linearized equations for the base station; Introducing intermediate variables Then consider the location of the fake base station. The measurement equation can be linearized into a linear equation: Step 4: Simultaneous solution; The linear equations of step 3 are formed by the synchronous readings of multiple laser interferometry units (4), an overdetermined system of equations is constructed, and the location of the fake base station is solved by the least squares method. ; Step 5: Solve the linearized equations at the end positions; Introducing intermediate variables Then the measurement equation can be linearized into a linear equation: Step 6: The linear equation from Step 5 is formed by the synchronous readings of multiple laser interferometry units (4), and the coordinates of the measurement end point are finally obtained by solving the equation. And no additional offset calibration is required during the process. ; The pseudo base station location compensation can absorb the offset of the multi-interface ball joint tooling (1) at the spindle end. The influence on the measurement equation should be considered to avoid biasing the multi-interface ball joint tooling (1) at the spindle end. Perform individual measurements and calibrations to achieve the coordinates of the measurement endpoints. The calculation.

4. The method for rapid measurement of machine tool geometric errors according to claim 3, characterized in that, The steps are as follows: Step 1: Trajectory execution; Set the machine tool running trajectory and control the machine tool to run according to the preset sequence XYZ, XZY, YXZ, YZX, ZXY or ZYX, and return to the starting point along the diagonal to form a closed trajectory; during operation, keep the machine tool spindle locked, the base end magnetic suction fixture (2) fixed and the laser interferometry unit (4) optical path aligned; X, Y, Z represent the machine tool running direction, which is the same as the X, Y, Z linear axis direction of the machine tool; Step 2: Trajectory point measurement; The coordinates of the discrete trajectory points at the ends of n laser interferometry units (4) obtained by collaborative measurement using multiple laser interferometry units: ， and the coordinates of its corresponding theoretical trajectory points. Pairing, the coordinates of the theoretical trajectory points are obtained based on the machine tool running trajectory set in step 1; Step 3: Calculate straightness error; The straightness error is calculated based on the coordinates of the discrete trajectory points at the end of the laser interferometry unit (4) and the coordinates of the theoretical trajectory points: in, It refers to the straightness error of the machine tool in the X direction. It refers to the straightness error of the machine tool in the Y direction. It is the straightness error of the machine tool in the Z direction; Step 4: Calculate the verticality deviation; The direction vectors of each axis are obtained by fitting the discrete trajectory. Calculate the perpendicularity deviation between axes: Among them, i=x, y, z, j=x, y, z, The X, Y, and Z direction vectors are the linear axes. Step 5: Cross-validation; The error distribution of the trajectory returning to the starting point along the diagonal in step 1 was used to compare and verify the linear axis measurement results.

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