Method for calculating correction parameters of motion errors in a machine tool and machine tool

Abstract

This invention provides a method for calculating correction parameters for motion errors in a machine tool, and the machine tool itself. The method comprises the following steps: a first measurement step, measuring three measuring surfaces A to C of a right-angle standard using a contact probe; a second right-angle calculation step, calculating a first right angle based on the measurement results of measuring surfaces A and B, and calculating a second right angle based on the measurement results of measuring surfaces A and C; a difference calculation step, calculating the difference between the two right angles; a judgment step, comparing the difference with a difference threshold; a right-angle identification step, calculating the average value of the two right angles if the difference is below the difference threshold, and calculating the angular deviation of the translation axis if the difference exceeds the difference threshold, and calculating a corrected right angle based on the angular deviation and either the first or second right angle; and a correction parameter setting step, setting the correction parameters based on the average value or the corrected right angle.

Description

Technical Field

[0001] This disclosure relates to a method for calculating correction parameters for correcting motion errors in a machine tool, and to the machine tool itself. Background Technology

[0002] Figure 1 This is a schematic diagram of a machining center M, which is an example of a machine tool with three translation axes. The machining center M has a spindle head 2 that can hold and rotate the tool and a worktable 3 that holds the workpiece.

[0003] The spindle head 2 can perform 2-degree-of-freedom translational motion relative to the bed 1 via mutually perpendicular translation axes Z and X. The worktable 3 can perform 1-degree-of-freedom translational motion relative to the bed 1 via a translation axis Y perpendicular to the Z and X axes. Each translation axis is driven by a servo motor controlled by a CNC device, causing the tool mounted on the spindle head 2 to rotate and process the workpiece fixed on the worktable 3 into arbitrary shapes.

[0004] As motion errors in machine tools, there are errors such as positioning errors, straightness, angular deviations (pitch, yaw, roll), and right angles, as described in Non-Patent Document 1. These motion errors are transferred to the shape of the workpiece, becoming the main cause of shape and dimensional errors in the workpiece. Reducing these motion errors to achieve high precision during the manufacturing and assembly stages of machinery presents challenges in terms of cost and technology. Therefore, correction techniques that consider motion errors and drive each axis have been developed.

[0005] To correct and control motion errors, it is necessary to measure and calculate the motion errors. Furthermore, since motion errors vary, it is important that measurements be performed periodically and without the use of specialized measuring equipment.

[0006] Non-Patent Literature 1 describes a method for measuring and evaluating motion errors. For example, in measuring angular deviations, a method using a precision level or an optical angular deviation measuring instrument is described. Furthermore, in measuring right angles, a method using a ruler, a right-angle ruler, and a micrometer is described.

[0007] Non-patent document 2 describes a measuring device that can simultaneously measure positioning error, straightness, and angular deviation using a laser.

[0008] In addition, Patent Document 1 proposes the following method: using a step gauge with multiple blocks and known distances between the blocks, the orientation of the step gauge is changed to multiple directions, the distance between the blocks is measured in each direction, and the positioning error of the translation axis and the right angle between the translation axes are determined / calculated.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2007-101279

[0012] Non-patent literature

[0013] Non-patent document 1: "Japanese Industrial Standard JIS B 6336-2:2002", [searched on July 14, 2004], Internet<https: / / kikakurui.com / b6 / B6336-2-2002-01.html>

[0014] Non-Patent Document 2: “XM-60 / XM-600 Multi-Behavior Calibrator”, Renishaw, [Searched July 14, 2005], Internet<https: / / www.renishaw.jp / jp / xm-60-and-xm-600-multi-axis-calibrator--39258> Summary of the Invention

[0015] The problem that the invention aims to solve

[0016] When measuring the right angle using the methods described in Non-Patent Document 1 and Patent Document 1, if the angular deviation of the translation axis is large, the right angle will vary depending on the measured position, making it impossible to determine uniquely. Furthermore, even if the command value is corrected by calculating correction parameters based on the measured right angle, the shape and dimensional errors of the workpiece are not improved.

[0017] On the other hand, in order to eliminate the influence of the angle deviation of the translation axis, it is necessary to measure the angle deviation and correct it, but there is a problem that the measurement requires special measurement as described in Non-Patent Documents 1 and 2.

[0018] Therefore, the purpose of this disclosure is to provide a method for calculating the correction parameters of motion error in a machine tool and the machine tool itself, which can properly measure and correct the motion error of the machine tool without using a special measuring instrument.

[0019] Methods for solving problems

[0020] To achieve the above objectives, the first structure disclosed herein is a method for calculating correction parameters for motion errors in a machine tool. This method involves using a right-angle standard in the machine tool to calculate the correction parameters. The machine tool includes: a worktable for holding a workpiece, a spindle for holding a tool, and three or more translation axes. The spindle is capable of relative motion with at least three degrees of freedom relative to the worktable. The method can correct the motion error of the translation axes according to predetermined correction parameters. The right-angle standard has a predetermined measuring surface A, measuring surfaces B and C that are perpendicular to and parallel to each other, and the angles formed by measuring surfaces A and B and between measuring surfaces A and C are known. The method is characterized by performing the following steps:

[0021] The first measurement step involves setting the right-angle standard on the workbench and measuring the measurement surfaces A, B, and C of the right-angle standard using a position measurement sensor mounted on the spindle.

[0022] The first right angle calculation step involves calculating the first right angle between the measuring surface A and the measuring surface B based on the measurement results of the measuring surface A and the measuring surface B in the first measurement step.

[0023] The second right angle calculation step involves calculating the second right angle between the measuring surface A and the measuring surface C based on the measurement results of the measuring surface A and the measuring surface C in the first measurement step.

[0024] The difference calculation step involves calculating the difference between the first right angle and the second right angle.

[0025] The determination step involves comparing the difference with a pre-set difference threshold.

[0026] The right-angle identification step involves, if the difference is below the difference threshold, calculating the average of the first right-angle and the second right-angle; conversely, if the difference exceeds the difference threshold, calculating the angle deviation of the translation axis, and calculating a corrected right-angle based on the angle deviation and either the first or second right-angle; and

[0027] The correction parameter setting step involves setting the correction parameter based on the average value or the correction angle.

[0028] Another aspect of the first structure disclosed herein is characterized in that, in the above structure, if the difference exceeds the difference threshold in the determination step, in the right angle identification step, the right angle standard is set at multiple locations, and the first determination step, the first right angle calculation step, the second right angle calculation step, and the difference calculation step are executed again at each of the locations, and the angle deviation is calculated based on the multiple differences obtained.

[0029] To achieve the above objectives, the second structure disclosed herein is a method for calculating correction parameters for motion errors in a machine tool. This method involves using a right-angle standard in the machine tool to calculate the correction parameters. The machine tool includes: a worktable for holding a workpiece, a spindle for holding a tool, and three or more translation axes. The spindle is capable of relative motion with at least three degrees of freedom of translation relative to the worktable. The method can correct the motion error of the translation axes according to predetermined correction parameters. The right-angle standard has a predetermined measuring surface A and a measuring surface B perpendicular to the measuring surface A, and the angle between the measuring surface A and the measuring surface B is known. The method is characterized by...

[0030] Perform the following steps:

[0031] The first measurement step involves setting the right-angle standard on the workbench and measuring the measuring surfaces A and B of the right-angle standard using a position measuring sensor mounted on the spindle.

[0032] The second measurement step involves changing the orientation of the right-angle standard and measuring the measurement surface A and the measurement surface B using the position measurement sensor.

[0033] The first right angle calculation step involves calculating the first right angle between the measuring surface A and the measuring surface B based on the measurement results of the measuring surface A and the measuring surface B in the first measurement step.

[0034] The second right angle calculation step involves calculating the second right angle between the measuring surface A and the measuring surface B based on the measurement results of the measuring surface A and the measuring surface B in the second measurement step.

[0035] The difference calculation step involves calculating the difference between the first right angle and the second right angle.

[0036] The determination step involves comparing the difference with a pre-set difference threshold.

[0037] The right-angle identification step involves calculating the average of the first right-angle and the second right-angle when the difference is below the difference threshold; conversely, calculating the angular deviation of the translation axis when the difference exceeds the difference threshold, and calculating a corrected right-angle based on the angular deviation and either the first or second right-angle.

[0038] The correction parameter setting step involves setting the correction parameter based on the average value or the correction angle.

[0039] Another aspect of the second structure disclosed herein is characterized in that, in the above structure, if the difference exceeds the difference threshold in the determination step, in the right angle identification step, the right angle standard is set at multiple locations, and the first measurement step, the second measurement step, the first right angle calculation step, the second right angle calculation step, and the difference calculation step are executed again at each of the locations, and the angle deviation is calculated based on the multiple differences obtained.

[0040] To achieve the above objectives, the third structure disclosed herein is a machine tool comprising: a worktable for holding a workpiece, a spindle for holding a tool, and three or more translation axes, wherein the spindle is capable of relative motion with respect to the worktable at three or more degrees of translational freedom, and is capable of correcting motion errors of the translation axes according to prescribed correction parameters, characterized in that it includes:

[0041] The first measuring unit, with a measuring surface A, a measuring surface B perpendicular to and parallel to the measuring surface A, and a measuring surface C set on the worktable, and with the angles formed by the measuring surfaces A and B and C known, measures the measuring surfaces A, B, and C of the right-angle standard respectively by a position measuring sensor installed on the spindle.

[0042] The first right angle calculation unit calculates the first right angle based on the measurement results of the first measuring unit on the measuring surface A and the measuring surface B.

[0043] The second right angle calculation unit calculates the second right angle based on the measurement results of the first measurement unit on the measurement surface A and the measurement surface C.

[0044] The difference calculation unit calculates the difference between the first rectangular angle and the second rectangular angle;

[0045] The determination unit compares the difference with a preset difference threshold; and

[0046] A right-angle recognition unit calculates the average of a first right-angle and a second right-angle when the difference is below the difference threshold; conversely, when the difference exceeds the difference threshold, it calculates the angular deviation of the translation axis and calculates a correction right-angle based on the angular deviation and either the first or second right-angle.

[0047] The correction parameter setting unit sets the correction parameter based on the average value or the correction angle.

[0048] To achieve the above objectives, the fourth structure disclosed herein is a machine tool comprising: a worktable for holding a workpiece, a spindle for holding a tool, and three or more translation axes, wherein the spindle is capable of relative motion with respect to the worktable at three or more degrees of translational freedom, and is capable of correcting motion errors of the translation axes according to prescribed correction parameters, characterized in that it includes:

[0049] The first measuring unit, with a right-angle standard having a specified measuring surface A and a measuring surface B perpendicular to the measuring surface A set on the workbench and the angle between the measuring surface A and the measuring surface B known, measures the measuring surface A and the measuring surface B of the right-angle standard respectively by a position measuring sensor installed on the spindle;

[0050] The second measuring unit changes the orientation of the right-angle standard and measures the measuring surface A and the measuring surface B through the position measuring sensor;

[0051] The first right angle calculation unit calculates the first right angle based on the measurement results of the first measuring unit on the measuring surface A and the measuring surface B.

[0052] The second right angle calculation unit calculates the second right angle based on the measurement results of the second measuring unit on the measuring surface A and the measuring surface B;

[0053] The difference calculation unit calculates the difference between the first rectangular angle and the second rectangular angle;

[0054] The determination unit compares the difference with a preset difference threshold.

[0055] A right-angle recognition unit calculates the average of a first right-angle and a second right-angle when the difference is below the difference threshold; conversely, when the difference exceeds the difference threshold, it calculates the angular deviation of the translation axis and calculates a correction right-angle based on the angular deviation and either the first or second right-angle.

[0056] The correction parameter setting unit sets the correction parameter based on the average value or the correction angle.

[0057] Invention Effects

[0058] According to this disclosure, by using a position measuring sensor to measure two or three measuring surfaces of a right-angle standard that serves as a precision reference, correction parameters for motion errors can be obtained without the use of special measuring instruments. Therefore, the motion errors of the machine tool can be appropriately corrected based on the obtained correction parameters. Furthermore, it is easy to determine whether the angular deviation of the translation axis adversely affects the measured right angle. Moreover, even when the angular deviation of the translation axis is large and the right angle cannot be uniquely determined, correction parameters can still be obtained by measuring the angular deviation of the translation axis. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of a machining center with translation axes of X, Y, and Z.

[0060] Figure 2 This is a functional block diagram of a CNC device.

[0061] Figure 3 This is a block diagram representing the control structure of a machining center.

[0062] Figure 4 This is a flowchart of the calculation method for the correction parameters.

[0063] Figure 5 This is a flowchart used to measure angular deviation.

[0064] Figure 6 This is an example of a right-angle standard.

[0065] Figure 7 This is an example of the parameters of a right-angle standard.

[0066] Figure 8 This is a schematic diagram of a contact probe and a right-angle standard set on the worktable.

[0067] Figure 9 This is a schematic diagram illustrating an example of a standard setting when measuring by changing the position of the right-angle standard.

[0068] Symbol Explanation

[0069] 1. Bed, 2. Spindle head, 3. Worktable, 11. Machining program, 12. Command value generation unit, 13. Servo command value conversion unit, 14a~14c. Servo driver, 15a~15c. Servo motor, 16. Calibration value calculation unit, 21. CNC device, 22. Recording unit, 23. Display unit, 24. Input unit, 25. Receiver, 101. Contact probe, G. Right angle standard, M. Machining center.

[0070] Specific implementation method

[0071] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0072] Here, we will illustrate the case of correction by measuring the perpendicularity between the X and Y axes and the angular deviation (yaw) of the Y axis. As an applicable machine tool, we will use... Figure 1 Let's take machining center M as an example for explanation. Figure 2 This is a functional block diagram of the CNC device 21.

[0073] In the CNC device 21, when the machining program 11 is input, the instruction value generation unit 12 generates the instruction value for each translation axis.

[0074] Based on the generated command value, the correction value of each axis is calculated by the correction value calculation unit 16. The sum of the command value and the correction value is sent to the servo command value conversion unit 13 to calculate the servo command value. The calculated servo command value of each axis is sent to the servo drivers 14a to 14c of each axis. The servo drivers 14a to 14c of each axis drive the servo motors 15a to 15c of each axis respectively, controlling the relative position of the spindle head 2 with respect to the worktable 3.

[0075] like Figure 3 As shown, the CNC device 21 has a recording unit 22, which can store calibration parameters, standard conditions, calibration parameter calculation programs, motion error correction programs, etc. Additionally, it includes a display unit 23 for transmitting information to the operator, an input unit 24 for inputting the object to be measured, and a receiver 25 for receiving the detection signal of the contact probe 101 (described later).

[0076] The correction parameters that form the basis of the correction value are recorded in the recording unit 22. The perpendicular angle between the X and Y axes, and if it is the Y-axis angle deviation (yaw), the Y-axis position and the angle deviation at that position are held as point group data. The angle deviation between each point is calculated by interpolation such as linear interpolation. If the perpendicular angle between the X and Y axes is γxy, and the Y-axis angle deviation (yaw) is EAY(i), then the correction value can be calculated by the following formula 1.

[0077] [Formula 1]

[0078] ΔCx=γxy(Y-Yk)

[0079] ΔCy=EAY(i)(X-Xk)

[0080] Here, ΔCx and ΔCy are the X-axis and Y-axis correction values, respectively; X and Y are the X-axis and Y-axis command values, respectively; and Xk and Yk are the X-axis and Y-axis correction reference positions, respectively.

[0081] Next, based on Figure 4 The flowchart illustrates the calculation method of the correction parameters executed by the CNC device 21. The CNC device 21 functions as the first measuring unit, the second measuring unit, the first right angle calculation unit, the second right angle calculation unit, the differential calculation unit, the judgment unit, the right angle identification unit, and the correction parameter setting unit of this disclosure.

[0082] First, the operator inputs the measurement error via input unit 24. This input is used to enable the CNC device 21 to identify what kind of error was being measured.

[0083] Figure 6 This is an example of a right-angle standard G used in error measurement. Figure 7 The calibration data of the measurement points (P100~P114) of the right-angle standard G shown are correlated with the input measurement error.

[0084] First, in step (hereinafter referred to as "S")1, as follows Figure 8 As shown, the operator sets the right-angle standard G on the worktable 3 with the measuring surface A parallel to the Y-axis, and installs a contact probe 101 on the spindle head 2, positioning it directly above the origin of the right-angle standard. The contact probe 101 has a stylus at its end; when the stylus contacts the object being measured, a signal is sent at that instant. When the CNC device 21 receives this signal through the connected receiver 25, it sets the position of each axis at that moment as the contact position, thereby determining the position.

[0085] Next, in S2, the measurement point (P) of the right-angle standard G is measured. 100 ~P 114 Measurement of ) (first measurement step). Measurement point (P) on measurement surface B. 100 ~P 104 At point A, the stylus is brought into contact with the object in the Y direction to measure the Y-direction position at each measurement point. At measurement point (P) on measurement surface A... 105 ~P 109 At point (P), the stylus is brought into contact with the object in the X direction, and the X-direction position at each measurement point is measured. At measurement point (P) on measurement surface C... 110 ~P 114 At point Y, the stylus is brought into contact with the point Y to measure the position of each measurement point in the Y direction.

[0086] Next, in S3, the right angle is calculated (the first and second right angle calculation steps). Regarding the measurement point (P) 100 ~P 104 ) and measurement point (P) 110 ~P 114 According to the measured Y-direction position (My) 100 ~My 104 ), (My 110 ~My 114 The X-axis command values ​​of each point are used to calculate the inclination a2 and a3 using methods such as least squares. Next, for the measurement point (P... 105 ~P 109 According to the measured X-direction position (Mx) 105 ~Mx 109 The tilt a1 is calculated using the Y-axis command values ​​of each point and the least squares method. Then, the right angles γxy1 and γxy2 are calculated using the following formula 2.

[0087] [Formula 2]

[0088] γxy1=a2-a1

[0089] γxy2=a3-a1

[0090] Next, in S4, the right angle difference Δγxy is calculated using the following equation 3 (difference calculation steps).

[0091] [Formula 3]

[0092] Δγxy=γxy2-γxy1

[0093] Next, in S5, the calculated right angle difference is compared with the difference threshold pre-recorded in the recording unit 22 (determination step). If it is determined in S5 that the right angle difference is below the difference threshold, in S6, the average value γxy' of the right angles γxy1 and γxy2 is calculated (right angle identification step).

[0094] On the other hand, if it is determined in S5 that the right angle difference is greater than the difference threshold, in S7, the necessity of measuring the angle deviation is displayed in the display unit 23.

[0095] Next, in S8, the angle deviation (yaw) is measured. Details regarding the angle deviation measurement will be described later.

[0096] Next, in S9, based on the angle deviation (yaw) EAY(i) calculated in S8 and the straight angle γxy1 calculated in S3, the straight angle γxy (corrected straight angle) considering the angle deviation is calculated according to the following formula 4 (S7~S9: straight angle identification step).

[0097] [Formula 4]

[0098] Δγxy=γxy1-EAY(Py 100 )

[0099] Here, EAY(Py 100 The θ is the angular deviation at the Y-axis position when the measurement point P100 of the right-angle standard G was measured in S2.

[0100] Next, in S10, either the average value of the right angle γxy' obtained in S6 or the right angle γxy” obtained in S9 is set as the correction parameter (correction parameter setting step).

[0101] The obtained correction parameters are recorded in recording unit 22. Figure 2 The correction value calculation unit 16 is used for the calculation of correction values ​​(e.g., the previous formula 1).

[0102] Next, based on Figure 5 The flowchart shown illustrates the measurement of the angular deviation of S8.

[0103] First, in S8-2, the position of the right-angle standard G is displayed on the display unit 23. The displayed position, for example, is... Figure 9 As shown, firstly, it is urged by setting the right-angle standard at position 1.

[0104] Next, in S8-3, the operator sets the right-angle standard G on the workbench 3 according to the displayed setting position, positioning it so that the contact probe 101 is directly above the origin of the right-angle standard.

[0105] Next, in S8-4, the three measuring surfaces A to C of the right-angle standard G are measured using the method described in S2.

[0106] Next, in S8-5, the two right angles γxy3 and γxy4 are calculated using the method described in S3, and the right angle difference Δγxy(Y1) is calculated using the method described in S4. S8-2 to S8-5 are repeated by changing the setting positions 2 to 5 of the right angle standard G.

[0107] Next, in S8-7, based on the obtained Δγxy(Y1)~Δγxy(Y5), the angle deviation (yaw) is calculated using the following formula 5.

[0108] [Formula 5]

[0109] EAY(i)=ΣΔγxy(i)

[0110] Thus, in the above-described method for calculating the correction parameters of motion error and in the machining center M, a contact probe 101 (position measurement sensor) installed on the spindle head 2 (spindle) is used to measure the three measuring surfaces A to C of the right-angle standard G, which serves as the accuracy reference. Based on the measurement results, two right angles are calculated and the difference between them is calculated. The right angle is identified based on the comparison between the difference and the difference threshold, and the correction parameters are set based on the identified right angle.

[0111] Based on this structure, correction parameters for motion errors can be obtained without using special measuring instruments. Therefore, the motion error of the machining center M can be appropriately corrected based on the obtained correction parameters. Furthermore, by comparing the difference between the two right angles with the difference threshold, it is easy to determine whether the angular deviation of the translation axis adversely affects the measured right angle. Moreover, even when the angular deviation of the translation axis is large and the right angle cannot be uniquely determined, correction parameters can still be obtained by measuring the angular deviation of the translation axis.

[0112] Furthermore, in the above-described method, the present disclosure is illustrated using a right-angle standard G having three measuring surfaces: measuring surface A, measuring surface B, and measuring surface C. However, the present disclosure can also be applied using a right-angle standard G having two measuring surfaces: measuring surface A and measuring surface B.

[0113] In this case, the measurement is performed in the machining center M, for example, by following these steps.

[0114] First, a right-angle standard G is set on the worktable 3, and the first measurement step is performed by measuring the measuring surface A and measuring surface B of the right-angle standard G through the contact probe 101 installed on the spindle head 2.

[0115] Next, the orientation of the right-angle standard G is changed (e.g., rotated 180 degrees around the X-axis) to perform the second measurement step of measuring the measurement surface A and the measurement surface B by means of the contact probe 101.

[0116] Next, based on the measurement results of measurement surface A and measurement surface B in the first measurement step, the first right angle calculation step is performed, which calculates the first right angle between measurement surface A and measurement surface B in the same manner as before.

[0117] Next, based on the measurement results of measurement surface A and measurement surface B in the second measurement step, the second right angle calculation step is performed, which calculates the second right angle between measurement surface A and measurement surface B in the same manner as before.

[0118] The subsequent processing is the same as before.

[0119] In this case, it is also possible to obtain the correction parameters for motion error without using special measuring instruments.

[0120] Furthermore, the machine tools disclosed herein are not limited to machining centers.

Claims

1. A method for calculating correction parameters for motion errors in a machine tool, comprising calculating correction parameters using a right-angle standard in the machine tool, wherein, This machine tool includes: a worktable for holding the workpiece, a spindle for holding the tool, and three or more translation axes. The spindle is capable of relative motion with more than three degrees of freedom relative to the worktable. It can correct motion errors of the translation axes according to specified correction parameters. The right-angle standard has a specified measuring surface A, a measuring surface B perpendicular to and parallel to the measuring surface A, and a measuring surface C. The angles formed by the measuring surface A and the measuring surface B, and the angles formed by the measuring surface A and the measuring surface C are known. The machine tool is characterized by performing the following steps: The first measurement step involves setting the right-angle standard on the workbench and measuring the measurement surfaces A, B, and C of the right-angle standard using a position measurement sensor mounted on the spindle. The first right angle calculation step involves calculating the first right angle between the measuring surface A and the measuring surface B based on the measurement results of the measuring surface A and the measuring surface B in the first measurement step. The second right angle calculation step involves calculating the second right angle between the measuring surface A and the measuring surface C based on the measurement results of the measuring surface A and the measuring surface C in the first measurement step. The difference calculation step involves calculating the difference between the first right angle and the second right angle. The determination step involves comparing the difference with a pre-set difference threshold. The right-angle identification step involves, if the difference is below the difference threshold, calculating the average of the first right-angle and the second right-angle; conversely, if the difference exceeds the difference threshold, calculating the angle deviation of the translation axis, and calculating a corrected right-angle based on the angle deviation and either the first or second right-angle; and The correction parameter setting step involves setting the correction parameter based on the average value or the correction angle.

2. The method for calculating the correction parameters of motion error in a machine tool according to claim 1, characterized in that, If the difference exceeds the difference threshold in the determination step, in the right angle identification step, the right angle standard is set at multiple locations, and the first measurement step, the first right angle calculation step, the second right angle calculation step, and the difference calculation step are executed again at each of the locations. The angle deviation is calculated based on the multiple differences obtained.

3. A method for calculating correction parameters for motion errors in a machine tool, wherein the method uses a right-angle standard in the machine tool to calculate the correction parameters, wherein... The machine tool includes: a worktable for holding the workpiece, a spindle for holding the tool, and three or more translation axes. The spindle is capable of relative motion with more than three degrees of freedom relative to the worktable. It can correct motion errors of the translation axes according to specified correction parameters. The right-angle standard has a specified measuring surface A and a measuring surface B perpendicular to the measuring surface A, and the angle between the measuring surface A and the measuring surface B is known. The machine tool is characterized by performing the following steps: The first measurement step involves setting the right-angle standard on the workbench and measuring the measuring surfaces A and B of the right-angle standard using a position measuring sensor mounted on the spindle. The second measurement step involves changing the orientation of the right-angle standard and measuring the measurement surface A and the measurement surface B using the position measurement sensor. The first right angle calculation step involves calculating the first right angle between the measuring surface A and the measuring surface B based on the measurement results of the measuring surface A and the measuring surface B in the first measurement step. The second right angle calculation step involves calculating the second right angle between the measuring surface A and the measuring surface B based on the measurement results of the measuring surface A and the measuring surface B in the second measurement step. The difference calculation step involves calculating the difference between the first right angle and the second right angle. The determination step involves comparing the difference with a pre-set difference threshold. The right-angle identification step involves, if the difference is below the difference threshold, calculating the average of the first right-angle and the second right-angle; conversely, if the difference exceeds the difference threshold, calculating the angle deviation of the translation axis, and calculating a corrected right-angle based on the angle deviation and either the first or second right-angle; and The correction parameter setting step involves setting the correction parameter based on the average value or the correction angle.

4. The method for calculating the correction parameters of motion error in a machine tool according to claim 3, characterized in that, If the difference exceeds the difference threshold in the determination step, in the right angle identification step, the right angle standard is set at multiple locations, and the first measurement step, the second measurement step, the first right angle calculation step, the second right angle calculation step, and the difference calculation step are executed again at each of the locations. The angle deviation is calculated based on the multiple differences obtained.

5. A machine tool comprising: a worktable for holding a workpiece, a spindle for holding a cutting tool, and three or more translation axes, wherein the spindle is capable of relative motion with respect to the worktable at three or more degrees of translational freedom, and is capable of correcting motion errors of the translation axes according to prescribed correction parameters, characterized in that... include: The first measuring unit, with a right-angle standard having a defined measuring surface A, a measuring surface B perpendicular to and parallel to the measuring surface A, and a measuring surface C set on the worktable, and with the angles formed by the measuring surfaces A and B and C known, measures the measuring surfaces A, B, and C of the right-angle standard respectively by a position measuring sensor mounted on the spindle. The first right angle calculation unit calculates the first right angle based on the measurement results of the first measuring unit on the measuring surface A and the measuring surface B. The second right angle calculation unit calculates the second right angle based on the measurement results of the first measurement unit on the measurement surface A and the measurement surface C. The difference calculation unit calculates the difference between the first rectangular angle and the second rectangular angle; The determination unit compares the difference with a preset difference threshold. as well as A right-angle recognition unit calculates the average of a first right-angle and a second right-angle when the difference is below the difference threshold; conversely, when the difference exceeds the difference threshold, it calculates the angular deviation of the translation axis and calculates a correction right-angle based on the angular deviation and either the first or second right-angle. The correction parameter setting unit sets the correction parameter based on the average value or the correction angle.

6. A machine tool comprising: a worktable for holding a workpiece, a spindle for holding a cutting tool, and three or more translation axes, wherein the spindle is capable of relative motion with respect to the worktable at least three degrees of freedom, and is capable of correcting motion errors of the translation axes according to prescribed correction parameters, characterized in that... include: The first measuring unit, with a right-angle standard having a specified measuring surface A and a measuring surface B perpendicular to the measuring surface A set on the workbench and the angle between the measuring surface A and the measuring surface B known, measures the measuring surface A and the measuring surface B of the right-angle standard respectively by a position measuring sensor installed on the spindle; The second measuring unit changes the orientation of the right-angle standard and measures the measuring surface A and the measuring surface B through the position measuring sensor; The first right angle calculation unit calculates the first right angle based on the measurement results of the first measuring unit on the measuring surface A and the measuring surface B. The second right angle calculation unit calculates the second right angle based on the measurement results of the second measuring unit on the measuring surface A and the measuring surface B; The difference calculation unit calculates the difference between the first rectangular angle and the second rectangular angle; The determination unit compares the difference with a preset difference threshold. A right-angle recognition unit calculates the average of a first right-angle and a second right-angle when the difference is below the difference threshold; conversely, when the difference exceeds the difference threshold, it calculates the angular deviation of the translation axis and calculates a correction right-angle based on the angular deviation and either the first or second right-angle. The correction parameter setting unit sets the correction parameter based on the average value or the correction angle.

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