A Method for RTCP Precision Detection and Compensation of a Numerical Control Machine Tool

Abstract

The present invention discloses a method for detecting and compensating RTCP precision of numerically controlled machine tools, which belongs to the field of numerically controlled machine tool control, including: installing a ball head inspection rod on a machine tool spindle; setting up a dial indicator and adjusting the dial indicator posture so that the indicator needle faces the Z positive direction of the machine tool, manually operating the machine tool so that the indicator needle contacts the highest point of the ball head, and rotating the dial of the dial indicator so that the pointer points to the zero position; detecting the Z-direction error by executing a fixed NC detection program, and evaluating the precision status, if the requirements are met, then performing the next precision detection; if the requirements are not met, then detecting and compensating the precision errors of each sub-item until the Z-direction error meets the requirements; detecting the X-direction and Y-direction errors in turn according to the same method until the errors in the three directions of X, Y, and Z meet the requirements. The present invention can detect the actual deviation of RTCP precision in three directions of space, can truly reflect the precision status of the machine tool, and perform error compensation through the compensation function provided by the system.

Description

Technical Field

[0001] The present invention relates to the field of RTCP accuracy control of numerically controlled machine tools, and particularly to a method for detecting and compensating the RTCP accuracy of numerically controlled machine tools. Background Art

[0002] RTCP accuracy is mainly used to evaluate the comprehensive accuracy of five-axis linkage numerically controlled machine tools, and is one of the most important accuracies of five-axis linkage numerically controlled machine tools. The quality of its accuracy directly affects the machining quality of parts. In the existing technology, when performing RTCP accuracy detection and compensation, there are detection and compensation blind spots, and the true accuracy status of the machine tool cannot be fully demonstrated.

[0003] In the existing technology, for example, in the periodicals "Research on RTCP Calibration Algorithm of Numerically Controlled Machine Tools Based on HNC-8 Type Five-Axis Linkage" and "RTCP Accuracy Detection and Correction Method for Five-Coordinate Machining Centers", and the patent "A Method for Calibrating RTCP Accuracy of CA-Type Five-Axis Numerically Controlled Machine Tools Based on Probe". The aforementioned methods all compensate for the Z-direction error of RTCP accuracy by detecting the vector deviation between the spindle axis and the axis of each swing axis or rotary axis. However, such technologies do not consider that errors in the X and Y directions of RTCP accuracy will also directly affect the machining quality of parts. Therefore, they cannot fully meet the RTCP accuracy debugging requirements of five-axis linkage numerically controlled machine tools.

[0004] Another example is the patents "A Method for Calibrating and Compensating RTCP of a Five-Axis Numerically Controlled Machine Tool with a Double Swivel Head Structure" and "Machine Tool Accuracy Compensation Method, Device, Storage Medium and Electronic Equipment". The aforementioned technical methods can all detect the errors in the X, Y, and Z directions of RTCP accuracy. However, in a conventional system such as Siemens 840D, there are no compensation parameters directly corresponding to the errors in the three directions of RTCP accuracy. In other words, even if the errors in the three directions are obtained, they cannot be directly compensated. Therefore, the parameter compensation of the above technologies requires secondary development to be realized, which undoubtedly increases the technical difficulty of error compensation.

[0005] In view of this, the present invention proposes a method for detecting and compensating the RTCP accuracy of numerically controlled machine tools. Summary of the Invention

[0006] The object of the present invention is to solve the problem that in the existing technology, when performing RTCP accuracy detection and compensation, there are detection and compensation blind spots, and the true accuracy status of the machine tool cannot be fully demonstrated. A method for detecting and compensating the RTCP accuracy of numerically controlled machine tools is proposed. This method can detect the true situation of the deviation of RTCP accuracy in three spatial directions, and perform error compensation based on the built-in compensation function of the machine tool, effectively solving the RTCP accuracy debugging problem.

[0007] In order to achieve the above object of the invention, the technical solution of the present invention is as follows:

[0008] A method for detecting and compensating the RTCP accuracy of a numerically controlled machine tool, comprising the following steps:

[0009] Step S1: Install a ball nose probe on the machine tool spindle and input the length in the length of the ball nose probe in the tool list.

[0010] Step S2: Set up a dial indicator and adjust the attitude of the dial indicator so that the pointer faces the positive Z direction of the machine tool. Manually operate the machine tool to make the pointer contact the highest point of the ball head, and rotate the dial of the dial indicator to make the pointer point to zero. By executing a fixed NC detection program, detect the Z-direction error of the RTCP accuracy and evaluate the RTCP accuracy status. If the requirements are met, proceed to the next accuracy detection; if the requirements are not met, it is necessary to detect and compensate for the accuracy errors of each item until the Z-direction error of the RTCP accuracy meets the requirements.

[0011] Step S3: Set up a dial indicator and adjust the attitude of the dial indicator so that the pointer faces the positive X direction of the machine tool. Manually operate the machine tool to make the pointer contact the highest point of the ball head, and rotate the dial of the dial indicator to make the pointer point to zero. By executing a fixed NC detection program, detect the X-direction error of the RTCP accuracy and evaluate the RTCP accuracy status. If the requirements are met, proceed to the next accuracy detection; if the requirements are not met, it is necessary to detect and compensate for the accuracy errors of each item until the X-direction error of the RTCP accuracy meets the requirements.

[0012] Step S4: Set up a dial indicator and adjust the attitude of the dial indicator so that the pointer faces the positive Y direction of the machine tool. Manually operate the machine tool to make the pointer contact the highest point of the ball head, and rotate the dial of the dial indicator to make the pointer point to zero. By executing a fixed NC detection program, detect the Y-direction error of the RTCP accuracy and evaluate the RTCP accuracy status. If the requirements are met, the detection and compensation are completed; if the requirements are not met, it is necessary to re-detect and compensate for the X and Z direction errors of the RTCP accuracy until the errors in the X, Y, and Z directions of the RTCP accuracy all meet the requirements.

[0013] In step S2, by executing a fixed NC detection program, detecting the Z-direction error of the RTCP accuracy includes: with the TRAORI instruction enabled, the machine tool sequentially moves to 8 composite angles θ formed by the combination of the swing axis A axis and the rotary axis C axis, and records the dial indicator values Z 1 ~Z 8 , where the angle of the A axis is selected as 90° and -90°, and the angles of the C axis are selected as 0°, 90°, 180°, and 270°.

[0014] In step S2, by executing a fixed NC detection program, detecting the Z-direction error of the RTCP accuracy includes: according to Z 1 ~Z 8Based on the value of

[0015] Judgment 1.1: When Z 1 ~Z 8 are all positive, △Z = Z max , Z max = [Z 1 ~Z 8 max ;

[0016] Judgment 1.2: When Z 1 ~Z 8 are all negative, △Z = |Z min |, Z min = [Z 1 ~Z 8 min ;

[0017] Judgment 1.3: When Z 1 ~Z 8 have both positive and negative values, △Z = Z max - Z min , Z max = [Z 1 ~Z 8 max , Z min = [Z 1 ~Z 8 min .

[0018] In step S2, evaluating the RTCP accuracy status includes performing a second-level judgment based on the calculated RTCP accuracy status △Z:

[0019] Judgment 2.1: When the value of △Z is less than the accuracy permission value, the Z-axis error of the RTCP accuracy meets the requirements;

[0020] Judgment 2.2: When the value of △Z is greater than or equal to the accuracy permission value, the Z-axis error of the RTCP accuracy does not meet the requirements, and it is necessary to calculate and compensate for the individual item errors that make up the RTCP accuracy. The individual item errors include the deviation between the main shaft and the A-axis in the Y direction, the deviation from the end face of the main shaft to the rotation center of the A-axis, and the C-axis rotation plane error.

[0021] In Judgment 2.2, calculating and compensating for the individual item errors that make up the RTCP accuracy includes:

[0022] Based on the dial indicator values Z 1 and Z 5 ​​​​, perform a third-level judgment on the three possible Z-value conditions that may occur, so as to calculate the deviation between the main shaft and the A-axis in the Y direction and the deviation from the end face of the main shaft to the rotation center of the A-axis:

[0023] Judgment 3.1: When Z 1 and Z 5 are both positive or both positive and negative, the deviation λ 1 between the main shaft and the A-axis in the Y direction = (Z max - Z min ) / 2, and the deviation λ 2 from the end face of the main shaft to the rotation center of the A-axis = Z max - (Z max - Z min ) / 2, Z max = [Z 1 , Z 5 max , Z min = [Z 1 , Z 5 min ;

[0024] Judgment 3.2: When Z 1 and Z 5 are both negative, calculate the deviation λ 1 between the main shaft and the A-axis in the Y direction = (Z min - Z max ) / 2, calculate the deviation λ 2 from the end face of the main shaft to the rotation center of the A-axis = Z min - (Z min - Z max ) / 2, Z max = [Z 1 , Z 5 max , Z min = [Z 1 , Z 5 min ;

[0025] Then, according to the calculated values of λ 1 and λ 2 , perform a fourth-level judgment:

[0026] Judgment 4.1: When the values of |λ 1 | and |λ 2 | are less than the precision-permitted value, this sub-item meets the requirements;

[0027] Judgment 4.2: When the values of |λ 1 | and |λ 2 | are greater than or equal to the precision-permitted value, the deviation λ 1 and the deviation λ 2 ​​​​Calculate with the respective original system parameter compensation values, and then compensate the calculated new values back into their respective original system parameters; after the compensation is completed, the dial indicator value Z needs to be detected again. 1 and Z 5 , and successively execute the above third-level and fourth-level judgments until the values of ∣λ 1 ∣ and ∣λ 2 ∣ are less than the precision-permitted values.

[0028] In Judgment 2.2, calculating and compensating for each sub-error component that makes up the RTCP precision includes:

[0029] Based on the dial indicator values Z 1 , Z 2 , Z 3 , Z 4 measured when the A-axis is at 90° or the dial indicator values Z 5 , Z 6 , Z 7 , Z 8 measured when the A-axis is at -90°, conduct a fifth-level judgment on three possible Z-value situations, and calculate the C-axis rotation plane error △C;

[0030] Judgment 5.1: When all Z-values are positive, △C = Z max , Z max = [Z 1 ~ Z 4 max or Z max = [Z 5 ~ Z 8 max ;

[0031] Judgment 5.2: When all Z-values are negative, △C = ∣Z min ∣, the Z min value is determined by the selected region in Judgment 5.1 above. If the selected region is [Z 1 ~ Z 4 , then Z min = [Z 1 ~ Z 4 min ; if the selected region is [Z 5 ~ Z 8 , then Z min = [Z 5 ~ Z 8 min ;

[0032] Judgment 5.3: When Z-values are both positive and negative, △C = Z max - Z min , Z max and Z min ​​​​The value is determined by the selected area in the above judgment 5.1. If the selected area is [Z 1 ~Z 4 , then Z max =[Z 1 ~Z 4 max , Z min =[Z 1 ~Z 4 min ; if the selected area is [Z 5 ~Z 8 , then Z max =[Z 5 ~Z 8 max , Z min =[Z 5 ~Z 8 min ;

[0033] Then, perform the sixth-level judgment according to the calculated C-axis rotation plane error △C:

[0034] Judgment 6.1: When the value of △C is less than the allowable precision value, the C-axis rotation plane meets the requirements;

[0035] Judgment 6.2: When the value of △C is greater than or equal to the allowable precision value, it is necessary to re-detect the precise error of the rotation plane, perform the manual alignment operation according to step S2, input the detection program and execute it. Set the machine tool feed rate to 100%, and the feed rate cannot be adjusted randomly during the detection. The detection program is as follows:

[0036] Execute G500 TRAORI; activate the machine tool coordinate system and the five-axis linkage function;

[0037] Execute G01 F500; set the moving speed;

[0038] Execute A90 C0, M0; move to the set angle θ 9 , rotate the dial of the dial indicator to make the pointer point to zero, and record the dial indicator reading Z 9 ;

[0039] Execute TRAFOOF, turn off the five-axis linkage function;

[0040] Execute A90 C90, M0; move to the set angle θ 10 , use the handwheel to move the X-axis and Y-axis, re-find the high points in the X and Y directions of the sphere, and record the dial indicator reading Z 10 ;

[0041] Execute A90 C180, M0; move to the set angle θ 11 ​​​​, use the handwheel to move the X-axis and Y-axis, re-find the high points of the sphere in the X and Y directions, and record the dial indicator reading Z 11 ;

[0042] Execute A90 C270, M0; move to the set angle θ 12 , use the handwheel to move the X-axis and Y-axis, re-find the high points of the sphere in the X and Y directions, and record the dial indicator reading Z 12 ;

[0043] Then reverse the superposition compensation for the dial indicator readings Z 9 、Z 10 、Z 11 、Z 12 obtained in the detection program, and use the machine tool sag compensation function to compensate the C-axis rotation plane with the Z-axis;

[0044] After the compensation is completed, execute step S2 again to ensure that the Z-axis error of the RTCP accuracy meets the requirements.

[0045] In step S3, the NC detection program for the X-axis error detection method of RTCP accuracy refers to that with the TRAORI instruction enabled, the machine tool moves to the 8 composite angles θ formed by the combination of the swing axis A-axis and the rotation axis C-axis, and records the dial indicator values X 1 ~X 8 ; At the same time, the angle of the A-axis is selected as 45° and -45°, and the angles of the C-axis are selected as 0°, 90°, 180°, 270°.

[0046] In step S3, detect the X-axis error of the RTCP accuracy by executing a fixed NC detection program, including:

[0047] According to the values of X 1 ~X 8 , make a first-level judgment on three possible X-value situations, and calculate the RTCP accuracy △X correspondingly:

[0048] Judgment 1.1: When X 1 ~X 8 are all positive, △X = X max , X max = [X 1 ~X 8 max ;

[0049] Judgment 1.2: When X 1 ~X 8 are all negative, △X = |X min |, X min = [X 1 ~X 8 min ​​;

[0050] Judgment 1.3: When X 1 ~X 8 has both positive and negative values, ΔX = X max -X min , X max =[X 1 ~X 8 max , X min =[X 1 ~X 8 min ;

[0051] Then, make a second-level judgment based on the calculated RTCP accuracy status ΔX:

[0052] Judgment 2.1: When the value of ΔX is less than the allowable accuracy value, the X-axis error of RTCP accuracy meets the requirements;

[0053] Judgment 2.2: When the value of ΔX is greater than or equal to the allowable accuracy value, the X-axis error of RTCP accuracy does not meet the requirements, and it is necessary to calculate the individual item errors that make up the RTCP accuracy and perform compensation. The individual item errors include the A-axis rotation plane error and the coaxiality error between the main shaft and the C-axis.

[0054] In Judgment 2.2, calculate the individual item errors that make up the RTCP accuracy and perform compensation, including:

[0055] Based on the values of X 1 and X 5 measured when the compound angle is A-axis 45° / C-axis 0° and A-axis -45° / C-axis 0° respectively, perform a third-level judgment. The judgment method is the same as the principle of the first-level judgment method to calculate the A-axis rotation plane error ΔA;

[0056] Then, make a fourth-level judgment based on the calculated A-axis rotation plane error ΔA:

[0057] Judgment 4.1: Judge whether the value of ΔA is less than the allowable accuracy value. When the value of ΔA is less than the allowable accuracy value, the A-axis rotation plane meets the requirements;

[0058] Judgment 4.2: When the value of ΔA is greater than or equal to the allowable accuracy value, it is necessary to re-detect the precise error of the rotation plane, perform a manual alignment operation according to step S3, then input the detection program and execute it. Set the machine tool feed rate to 100%. During the detection process, the feed rate cannot be adjusted randomly. The specific program is as follows:

[0059] Execute G500 TRAFOOF; Activate the machine tool coordinate system and turn off the five-axis linkage function;

[0060] Execute G01 F500; Set the moving speed;​​

[0061] Execute A - 90 C0, M0; Move to the set angle θ 9 , Use the handwheel to move the Y and Z axes, re - find the high points of the sphere in the Y - direction and Z - direction, and record the dial indicator reading X 9 ; Move Z to the safe point;

[0062] Execute A - 45 C0, M0; Move to the set angle θ 10 , Use the handwheel to move the Y and Z axes, re - find the high points of the sphere in the Y - direction and Z - direction, and record the dial indicator reading X 10 ; Move Z to the safe point;

[0063] Execute A45 C0, M0; Move to the set angle θ 11 , Use the handwheel to move the Y and Z axes, re - find the high points of the sphere in the Y - direction and Z - direction, and record the dial indicator reading X 11 ; Move Z to the safe point;

[0064] Execute A90 C0, M0; Move to the set angle θ 12 , Use the handwheel to move the X - axis and Y - axis, re - find the high points of the sphere in the Y - direction and Z - direction, and record the dial indicator reading X 12 ; Move Z to the safe point.

[0065] Then reverse - superpose and compensate the values of the dial indicator readings X 9 , X 10 , X 11 , X 12 , and use the machine tool sag compensation function to compensate the A - axis rotation plane with the X - axis.

[0066] After the compensation is completed, detect the dial indicator values X1 and X5 again, and sequentially execute the above - mentioned third - level and fourth - level judgments until the value of △A is less than the accuracy - permitted value.

[0067] In Judgment 2.2, calculate and compensate each sub - error that composes the RTCP accuracy, including:

[0068] According to the values of X1, X2, X3, X4 measured when the A - axis is 45° or the values of X5, X6, X7, X8 measured when the A - axis is - 45°, execute the fifth - level judgment to calculate the coaxiality error △C between the spindle and the C - axis:

[0069] Judgment 5.1: When all X values are positive, △C = X max , X max =[X 1 ~X 4 max or X max =[X 5 ~X 8 ​max ;

[0070] Judgment 5.2: When all X values are negative, △C = |X min |, and the Z min value is determined by the selected region in the above Judgment 5.1. If the selected region is [X 1 ~X 4 , then X min = [X 1 ~X 4 min ; If the selected region is [X 5 ~X 8 , then X min = [X 5 ~X 8 min ;

[0071] Judgment 5.3: When X values are both positive and negative, △C = X max - X min , and the X max and X min values are determined by the selected region in the above Judgment 5.1. If the selected region is [X 1 ~X 4 , then X max = [X 1 ~X 4 max , X min = [X 1 ~X 4 min ; If the selected region is [X 5 ~X 8 , then X max = [X 5 ~X 8 max , X min = [X 5 ~X 8 min ;

[0072] Perform the sixth-level judgment based on the calculated coaxiality error △C between the main shaft and the C axis:

[0073] Judgment 6.1: When the value of △C is less than the allowable accuracy value, the coaxiality between the main shaft and the C axis meets the requirements;

[0074] Judgment 6.2: When the value of △C is greater than or equal to the allowable accuracy value, it is necessary to re-detect the precise coaxiality error between the main shaft and the C axis, perform the manual alignment operation according to the above step S3, then input the detection program and execute it. Set the machine feed rate multiplier to 100%. Do not adjust the multiplier randomly during the detection process. The specific program is as follows: ​​​​​​​

[0075] Execute G500 TRAORI; activate the machine coordinate system and the five-axis linkage function;

[0076] Execute G01 F500; set the speed;

[0077] Execute A0 C0, G4 F3; move to the set angle θ 9 , record the dial indicator reading X 11；

[0078] Execute A0 C90, G4 F3; move to the set angle θ 10 , record the dial indicator reading X 12；

[0079] Execute A0 C180, G4 F3; move to the set angle θ 11 , record the dial indicator reading X 13；

[0080] Execute A0 C270, G4 F3; move to the set angle θ 12 , record the dial indicator reading X 14。

[0081] Calculate the deviation λ of the coaxiality between the spindle and the C-axis in the X direction 3 =X 11 -X 13 , then the deviation compensation value λ of the coaxiality between the spindle and the C-axis in the X direction 4 =λ 3 / 2; calculate the deviation λ of the coaxiality between the spindle and the C-axis in the Y direction 5 =X 12 -X 14 , then the deviation compensation value λ of the coaxiality between the spindle and the C-axis in the Y direction 6 =λ 5 / 2; Compare the compensation value λ 4 with λ 6 respectively calculate with their respective original system parameter compensation values, and the calculated new values are compensated back to their respective original system parameters again; after the compensation is completed, the detection program in 4.2 needs to be executed again to detect and calculate λ 3 and λ 5 values until λ 3 and λ 5 values are less than the precision allowable values;

[0082] After the compensation is completed, execute the above step S3 again to ensure that the X-direction error of the RTCP accuracy meets the requirements.

[0083] In step S4, the NC detection program is the same as the program in step S2, and a total of 8 composite angles θ are detected 1 ~θ 8, the corresponding dial indicator reading is Y 1 ~Y 8 ; According to Y 1 ~Y 8 calculate the RTCP accuracy △Y;

[0084] Judgment 1.1: When the Y values are all positive, △Y = Y max , Y max = [Y 1 ~Y 8 max ;

[0085] Judgment 1.2: When the Y values are all negative, △Y = |Y min |, Y max = [Y 1 ~Y 8 max ;

[0086] Judgment 1.3: When the Y values are both positive and negative, △Y = Y max -Y min , Y max = [Y 1 ~Y 8 max , Y max = [Y 1 ~Y 8 max ;

[0087] Then perform the second-level judgment according to the calculated RTCP accuracy status △Y:

[0088] Judgment 2.1: When the value of △Y is less than the accuracy permission value, the Y-direction error of the RTCP accuracy meets the requirements;

[0089] Judgment 2.2: When the value of △Y is greater than or equal to the accuracy permission value, it means that the Z-direction error and Y-direction error of the RTCP accuracy are affected when compensating the X-direction error of the RTCP accuracy. Therefore, it is necessary to re-detect and compensate the Z and X-direction errors of the RTCP accuracy until the X, Y, and Z direction errors of the RTCP accuracy all meet the requirements.

[0090] To sum up, the present invention has the following advantages:

[0091] By setting the RTCP accuracy detection program for the CA type five-axis linkage CNC machine tool, the errors in the X, Y, and Z directions of the machine tool when moving to the 4 quadrants of the machine tool space after the RTCP function is turned on are detected. When the error exceeds the set threshold, systematic judgment and detection are carried out on the factors affecting the RTCP accuracy, and error compensation is carried out through the compensation function built in the system, improving the reliability of RTCP accuracy detection and compensation. ​​​​Brief Description of the Drawings

[0092] Figure 1 is the flowchart of the RTCP accuracy detection and compensation operation of the present invention;

[0093] Figure 2 is the schematic diagram of the detection in the three directions of X, Y, and Z of the present invention;

[0094] Figure 3 is the schematic diagram of the movement trajectory of the Z - direction detection of the present invention;

[0095] Figure 4 is the schematic diagram of the movement trajectory of the X - direction detection of the present invention;

[0096] Figure 5 is the schematic diagram of the movement trajectory of the Y - direction detection of the present invention. Detailed Embodiment

[0097] To more clearly illustrate the present invention, the present invention will be further described below in conjunction with preferred embodiments and the drawings. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention.

[0098] Embodiment 1

[0099] This embodiment provides a method for detecting and compensating the RTCP accuracy of a numerically controlled machine tool. The following measuring instruments are required for this compensation method: 1) dial indicator and stand; 2) ball - end inspection bar; 3) mandrel. The specific method steps are as follows:

[0100] Step 1: Install the ball - end inspection bar on the machine tool spindle, and input the length L in the length of the ball - end inspection bar in the tool list, where L = H - R / 2, H is the total length of the ball - end inspection bar, and R is the diameter of the sphere at the top of the ball - end inspection bar. The data of H and R can be measured by a tool setter.

[0101] Step 2: Detect and compensate the Z - direction error of the RTCP accuracy. The operation steps are as follows:

[0102] Step S1: Execute the program: G01 F500 A0 C0 M2 to make the A / C axis in the zero position. Then install the dial indicator and stand on the workbench, adjust the attitude of the dial indicator so that the pointer faces the positive Z - direction of the machine tool, as Figure 1 shown; Use the handwheel to move the machine tool so that the sphere at the top of the ball - end inspection bar contacts the pointer of the dial indicator. Move the X - axis in the positive and negative directions to find the highest point of the ball in the X - direction; Move the Y - axis in the positive and negative directions to find the highest point of the ball in the Y - direction; Move the Z - axis in the positive and negative directions to make the sphere contact the pointer again and make the dial indicator compress by 0.2 mm, and rotate the dial of the dial indicator to make the pointer point to zero.

[0103] Step S2: Input the RTCP detection program and execute it. Set the machine tool feed rate to 100%. Do not adjust the feed rate randomly during the detection process. The specific program is as follows:

[0104] (1) Execute G500 TRAORI; activate the machine tool coordinate system and the five-axis linkage function;

[0105] (2) Execute G01 F500; set the moving speed;

[0106] (3) Execute A90 C0, G4 F3; move to the set angle θ 1 and stop for 3 seconds, record the dial indicator reading Z 1；

[0107] (4) Execute A90 C90, G4 F3; move to the set angle θ 2 and stop for 3 seconds, record the dial indicator reading Z 2；

[0108] (5) Execute A90 180, G4 F3; move to the set angle θ 3 and stop for 3 seconds, record the dial indicator reading Z 3；

[0109] (6) Execute A90 C270, G4 F3; move to the set angle θ 4 and stop for 3 seconds, record the dial indicator reading Z 4；

[0110] (7) Execute A-90 C0, G4 F3; move to the set angle θ 5 and stop for 3 seconds, record the dial indicator reading Z 5；

[0111] (8) Execute A-90 C90, G4 F3; move to the set angle θ 6 and stop for 3 seconds, record the dial indicator reading Z 6；

[0112] (9) Execute A-90 180, G4 F3; move to the set angle θ 7 and stop for 3 seconds, record the dial indicator reading Z 7；

[0113] (10) Execute A-90 C270, G4 F3; move to the set angle θ 8 and stop for 3 seconds, record the dial indicator reading Z 8；

[0114] (11) Execute A0 C0, M30; return to the zero position of the A / C axis and end the program.

[0115] The movement trajectory is asFigure 3 As shown in the figure, the corresponding relationship between the movement combinations at various angles and the dial indicator readings is as follows in Table 1:

[0116] Table 1 Corresponding relationship between the movement combinations at various angles and the dial indicator readings

[0117]

[0118] Step S3: Further, according to the Z values detected in the above Step S2, perform a first-level judgment on the three possible Z value conditions, and calculate the RTCP accuracy condition △Z: 1 ~Z 8 values, and calculate the RTCP accuracy condition △Z by performing a first-level judgment on the three possible Z value conditions that may occur:

[0119] Judgment 1.1: When the Z values are all positive, △Z = Z max , Z max = [Z 1 ~Z 8 max ;

[0120] Judgment 1.2: When the Z values are all negative, △Z = |Z min |, Z min = [Z 1 ~Z 8 min ;

[0121] Judgment 1.3: When the Z values are both positive and negative, △Z = Z max - Z min , Z max = [Z 1 ~Z 8 max , Z min = [Z 1 ~Z 8 min ;

[0122] Further, perform a second-level judgment based on the calculated RTCP accuracy condition △Z:

[0123] Judgment 2.1: When the value of △Z is less than the accuracy permission value, it can be considered that the Z-direction error of the RTCP accuracy meets the requirements.

[0124] Judgment 2.2: When the value of △Z is greater than or equal to the accuracy permission value, it can be considered that the Z-direction error of the RTCP accuracy does not meet the requirements, and it is necessary to calculate the individual item errors that make up the RTCP accuracy and perform compensation. The individual item errors include the deviation between the main shaft and the A axis in the Y direction, the deviation from the end face of the main shaft to the rotation center of the A axis, and the C axis rotation plane error.

[0125] Further, according to Z 1 and Z 5 ​​​​The numerical values are used to perform a third-level judgment on three possible Z-value conditions, and the deviation between the main shaft and the A-axis in the Y direction and the deviation between the end face of the main shaft and the rotation center of the A-axis are calculated.

[0126] Judgment 3.1: When both Z 1 and Z 5 are positive or both positive and negative values exist, calculate the deviation λ 1 = (Z max - Z min ) / 2, calculate the deviation λ 2 = Z max - (Z max - Z min ) / 2, Z max = [Z 1 , Z 5 max , Z min = [Z 1 , Z 5 min ;

[0127] Judgment 3.2: When both Z 1 and Z 5 are negative, calculate the deviation λ 1 = (Z min - Z max ) / 2, calculate the deviation λ 2 = Z min - (Z min - Z max ) / 2, Z max = [Z 1 , Z 5 max , Z min = [Z 1 , Z 5 min ;

[0128] Furthermore, based on the calculated values of λ 1 and λ 2 , perform a fourth-level judgment:

[0129] Judgment 4.1: When the numerical values of |λ 1 | and |λ 2 | are less than the precision-permitted numerical values, it can be considered that this sub-item meets the requirements.

[0130] Judgment 4.2: When the numerical values of |λ 1 | and |λ 2 | are greater than or equal to the precision-permitted numerical values, the deviations λ 1 and the deviation λ​​​​2 Calculate with the respective original system parameter compensation values, and compensate the calculated new values back into their respective original system parameters; after the compensation is completed, the procedures (1), (2), (3), and (7) in step S2 above need to be executed again, and the third-level and fourth-level judgments are executed in sequence until the values of ∣λ 1 ∣ and ∣λ 2 ∣ are less than the precision-permitted values.

[0131] Further, based on the values of Z 1 、Z 2 、Z 3 、Z 4 or the values of Z 5 、Z 6 、Z 7 、Z 8 perform a fifth-level judgment on the possible three Z-value situations to evaluate the C-axis rotation plane error △C;

[0132] Judgment 5.1: When the Z values are all positive, △C = Z max , Z max = [Z 1 ~Z 4 max or Z max = [Z 5 ~Z 8 max ;

[0133] Judgment 5.2: When the Z values are all negative, △C = ∣Z min ∣, the value of Z min is determined by the selected area in Judgment 5.1 above. If the selected area is [Z 1 ~Z 4 , then Z min = [Z 1 ~Z 4 min ; if the selected area is [Z 5 ~Z 8 , then Z min = [Z 5 ~Z 8 min ;

[0134] Judgment 5.3: When the Z values are both positive and negative, △C = Z max - Z min , the values of Z max and Z min are determined by the selected area in Judgment 5.1 above. If the selected area is [Z 1 ~Z 4 , then Z max = [Z 1 ​​​​~Z 4 max ,Z min =[Z 1 ~Z 4 min ; If the selected area is [Z 5 ~Z 8 , then Z max =[Z 5 ~Z 8 max ,Z min =[Z 5 ~Z 8 min ;

[0135] Further, perform the sixth-level judgment according to the calculated C-axis rotation plane error △C:

[0136] Judgment 6.1: When the value of △C is less than the allowable accuracy value, it can be considered that the C-axis rotation plane meets the requirements;

[0137] Judgment 6.2: When the value of △C is greater than or equal to the allowable accuracy value, it is necessary to re-detect the accurate error of the rotation plane, operate according to the above step S1, input the detection program and execute it, set the machine tool feed rate to 100%, and the feed rate cannot be adjusted randomly during the detection process. The specific program is as follows:

[0138] (12) Execute G500 TRAORI; activate the machine tool coordinate system and the five-axis linkage function;

[0139] (13) Execute G01 F500; set the moving speed;

[0140] (14) Execute A90 C0, M0; move to the set angle θ 9 , rotate the dial of the dial indicator to make the pointer point to zero, and record the dial indicator reading Z 9；

[0141] (15) Execute TRAFOOF, turn off the five-axis linkage function;

[0142] (16) Execute A90 C90, M0; move to the set angle θ 10 , use the handwheel to move the X-axis and Y-axis, re-find the high points in the X and Y directions of the sphere, and record the dial indicator reading Z 10；

[0143] (17) Execute A90 C180, M0; move to the set angle θ 11 , use the handwheel to move the X-axis and Y-axis, re-find the high points in the X and Y directions of the sphere, and record the dial indicator reading Z 11；

[0144] ​​​​Execute A90 C270, M0; Move to the set angle θ 12 , Use the handwheel to move the X-axis and Y-axis, re-find the high points of the sphere in the X and Y directions, and record the dial indicator reading Z 12；

[0145] Furthermore, reverse the superposition compensation for the dial indicator readings Z 9 、Z 10 、Z 11 、Z 12 values, and use the machine tool sag compensation function to compensate the C-axis rotation plane with the Z-axis. The compensation program is as follows:

[0146] ﹩AN_CEC[5, 0]=-Z 9 ; Compensation value at A90 C0;

[0147] ﹩AN_CEC[5, 90]=-Z 10 ; Compensation value at A90 C90;

[0148] ﹩AN_CEC[5, 180]=-Z 11 ; Compensation value at A90 C180;

[0149] ﹩AN_CEC[5, 270]=-Z 12 ; Compensation value at A90 C270;

[0150] ﹩AN_CEC_INPUT[5]=(Z); The input axis is the Z-axis;

[0151] ﹩AN_CEC_OUTPUT[5]=(C); The output axis is the C-axis;

[0152] ﹩AN_CEC_STEP[5]=90; The compensation interval is 90 degrees;

[0153] ﹩AN_CEC_MIN[5]=0; The starting point is C0;

[0154] ﹩AN_CEC_MAX[5]=270; The ending point is C270.

[0155] Furthermore, after the compensation is completed, the above steps S1 to S3 should be executed again to ensure that the Z-direction error of the RTCP accuracy meets the requirements.

[0156] Step 3. Detect and compensate the X-direction error of the RTCP accuracy:

[0157] Set up the dial indicator and adjust its attitude so that the pointer faces the positive X direction of the machine tool. Manually operate the machine tool to make the pointer contact the highest point of the ball head, and rotate the dial of the dial indicator to make the pointer point to zero. By executing a fixed NC detection program, detect the X-direction error of the RTCP accuracy and evaluate the RTCP accuracy status. If the requirements are met, proceed to the next accuracy detection; if not, it is necessary to detect and compensate for the accuracy errors of each item until the X-direction error of the RTCP accuracy meets the requirements.

[0158] Step 4: Detect the Y-direction error of the RTCP accuracy:

[0159] Set up the dial indicator and adjust its attitude so that the pointer faces the positive Y direction of the machine tool. Manually operate the machine tool to make the pointer contact the highest point of the ball head, and rotate the dial of the dial indicator to make the pointer point to zero. By executing a fixed NC detection program, detect the Y-direction error of the RTCP accuracy and evaluate the RTCP accuracy status. If the requirements are met, the detection and compensation are completed; if not, it is necessary to re-detect and compensate for the X- and Z-direction errors of the RTCP accuracy until the errors in the X, Y, and Z directions of the RTCP accuracy all meet the requirements.

[0160] Example 2

[0161] On the basis of Example 1, this example further explains the detection and compensation of the X-direction error of the RTCP accuracy in Step 3. The operation steps are as follows:

[0162] Step S1: Execute the program: G01 F500 A0 C0 M2 to make the A / C axes at zero position. Adjust the attitude of the dial indicator so that the pointer faces the positive X direction of the machine tool, as Figure 1 shown; use the handwheel to move the machine tool to make the top sphere of the ball probe contact the pointer of the dial indicator. Move the Y axis in the positive and negative directions to find the highest point of the ball head in the Y direction; move the Z axis in the positive and negative directions to find the highest point of the ball head in the Z direction; move the X axis in the positive and negative directions to make the sphere contact the pointer again and make the dial indicator press the table by 0.2 mm, and rotate the dial of the dial indicator to make the pointer point to zero.

[0163] Step S2: Input the RTCP detection program and execute it. Set the feed rate of the machine tool to 100%. Do not adjust the rate randomly during the detection process. The specific program is as follows:

[0164] (19) Execute G500 TRAORI; activate the machine tool coordinate system and the five-axis linkage function;

[0165] (20) Execute G01 F500; set the moving speed;

[0166] (21) Execute A45 C0, G4 F3; move to the set angle θ 1 and stop for 3 seconds, and record the dial indicator reading X 1；

[0167] (22) Execute A45 C90, G4 F3; Move to the set angle θ 2 And stop for 3 seconds, record the dial indicator reading X 2；

[0168] (23) Execute A45 180, G4 F3; Move to the set angle θ 3 And stop for 3 seconds, record the dial indicator reading X 3；

[0169] (24) Execute A45 C270, G4 F3; Move to the set angle θ 4 And stop for 3 seconds, record the dial indicator reading X 4；

[0170] (25) Execute A - 45 C0, G4 F3; Move to the set angle θ 5 And stop for 3 seconds, record the dial indicator reading X 5；

[0171] (26) Execute A - 45 C90, G4 F3; Move to the set angle θ 6 And stop for 3 seconds, record the dial indicator reading X 6；

[0172] (27) Execute A - 45 180, G4 F3; Move to the set angle θ 7 And stop for 3 seconds, record the dial indicator reading X 7；

[0173] (28) Execute A - 45 C270, G4 F3; Move to the set angle θ 8 And stop for 3 seconds, record the dial indicator reading X 8；

[0174] (29) Execute A0 C0, M30, Return to the A / C axis zero position and end the program.

[0175] The movement trajectory is as Figure 4 shown, and the corresponding relationship between each angular movement combination and the corresponding reading is as shown in Table 2 below:

[0176] Table 2 Corresponding relationship between each angular movement combination and the dial indicator reading

[0177]

[0178] Step S3: Further, based on the X 1 ~X 8 values checked in step S2 of this embodiment, and perform a first - level judgment on three possible X - value situations, calculate the RTCP accuracy situation △X:

[0179] Judgment 1.1: When all X values are positive, △X = X max , X max = [X 1 ~X 8 max ;

[0180] Judgment 1.2: When all X values are negative, △X = |X min |, X min = [X 1 ~X 8 min ;

[0181] Judgment 1.3: When X values are both positive and negative, △X = X max - X min , X max = [X 1 ~X 8 max , X min = [X 1 ~X 8 min ;

[0182] Furthermore, perform a second-level judgment based on the calculated RTCP accuracy status △X:

[0183] Judgment 2.1: When the value of △X is less than the accuracy tolerance value, it can be considered that the X-axis error of RTCP accuracy meets the requirements;

[0184] Judgment 2.2: When the value of △X is greater than or equal to the accuracy tolerance value, it can be considered that the X-axis error of RTCP accuracy does not meet the requirements, and it is necessary to calculate the individual errors that make up RTCP accuracy and perform compensation. The individual errors include the A-axis rotation plane error and the coaxiality error between the main shaft and the C-axis.

[0185] Furthermore, based on the X 1 and X 5 values, perform a third-level judgment on the three possible X-value conditions to evaluate the A-axis rotation plane error △A;

[0186] Judgment 3.1: When all X values are positive, △A = X max , X max = [X 1 , X 5 max；

[0187] Judgment 3.2: When all X values are negative, △A = |X min |, X min = [X 1 , X 5 ​​​​​​min；

[0188] Judgment 3.3: When the X value has both positive and negative values, △A = X max -X min , X max = [X 1 , X 5 max , X min = [X 1 , X 5 min。

[0189] Further, perform a fourth-level judgment based on the calculated A-axis rotation plane error △A:

[0190] Judgment 4.1: When the value of △A is less than the precision allowable value, it can be considered that the A-axis rotation plane meets the requirements.

[0191] Judgment 4.2: When the value of △A is greater than or equal to the precision allowable value, it is necessary to re-detect the precise error of the rotation plane, operate according to step S1 in the above-mentioned Embodiment 2, input the detection program and execute it, set the machine tool feed rate to 100%, and the feed rate cannot be adjusted randomly during the detection process. The specific program is as follows:

[0192] (30) Execute G500 TRAFOOF; activate the machine tool coordinate system and turn off the five-axis linkage function;

[0193] (31) Execute G01 F500; set the moving speed;

[0194] (32) Execute A-90 C0, M0; move to the set angle θ 9 , use the handwheel to move the Y and Z axes, re-find the high points of the sphere in the Y and Z directions, and record the dial indicator reading X 9 ; move Z to the safe point;

[0195] (33) Execute A-45 C0, M0; move to the set angle θ 10 , use the handwheel to move the Y and Z axes, re-find the high points of the sphere in the Y and Z directions, and record the dial indicator reading X 10 ; move Z to the safe point;

[0196] (34) Execute A45 C0, M0; move to the set angle θ 11 , use the handwheel to move the Y and Z axes, re-find the high points of the sphere in the Y and Z directions, and record the dial indicator reading X 11 ; move Z to the safe point;

[0197] (35) Execute A90 C0, M0; move to the set angle θ 12 ​​, use the handwheel to move the X-axis and Y-axis, relocate the high points of the sphere in the Y and Z directions, and record the dial indicator reading X 12 ; Move Z to the safe point.

[0198] Further, reverse the superposition compensation for the dial indicator readings X 9 、X 10 、X 11 、X 12 , and utilize the machine tool sag compensation function to use the X-axis to compensate the A-axis rotation plane. The compensation program is as follows:

[0199] ﹩AN_CEC[4, -90]=-X 9 ; Compensation value when A - 90 C0;

[0200] ﹩AN_CEC[4, -45]=-X 10 ; Compensation value when A - 45 C0;

[0201] ﹩AN_CEC[4, 0]=0; Compensation value when A0 C0;

[0202] ﹩AN_CEC[4, 45]=-X 11 ; Compensation value when A45 C0;

[0203] ﹩AN_CEC[4, 90]=-X 12 ; Compensation value when A90 C0;

[0204] ﹩AN_CEC_INPUT[4]=(X); Input axis is the X-axis;

[0205] ﹩AN_CEC_OUTPUT[4]=(A); Output axis is the A-axis;

[0206] ﹩AN_CEC_STEP[4]=45; Compensation interval is 45 degrees;

[0207] ﹩AN_CEC_MIN[4]=-90; Starting point is C - 90;

[0208] ﹩AN_CEC_MAX[4]=90; End point is C90.

[0209] Further, after the compensation is completed, execute the programs (19)(20)(21)(25) in step S2 of this embodiment again, and sequentially execute the third-level and fourth-level judgments in this embodiment until the value of △A is less than the precision allowable value.

[0210] Further, according to X 1 、X 2 、X 3 、X 4 's value or X5 , X 6 , X 7 , X 8 values, and perform a fifth-level judgment on three possible X-value conditions to evaluate the coaxiality error ΔC between the main axis and the C-axis;

[0211] Judgment 5.1: When the X values are all positive, ΔC = X max , X max = [X 1 ~ X 4 max or X max = [X 5 ~ X 8 max ;

[0212] Judgment 5.2: When the X values are all negative, ΔC = |X min |, and the Z min value is determined by the area selected in Judgment 5.1 above. If the selected area is [X 1 ~ X 4 , then X min = [X 1 ~ X 4 min ; if the selected area is [X 5 ~ X 8 , then X min = [X 5 ~ X 8 min ;

[0213] Judgment 5.3: When the X values are both positive and negative, ΔC = X max - X min , and the X max and X min values are determined by the area selected in Judgment 5.1 above. If the selected area is [X 1 ~ X 4 , then X max = [X 1 ~ X 4 max , and X min = [X 1 ~ X 4 min ; if the selected area is [X 5 ~ X 8 , then X max = [X 5 ~ X 8 max , and X min = [X 5 ~ X 8 ​​​​​​​​min ;

[0214] Further, perform a sixth-level judgment according to the calculated coaxiality error ΔC between the main shaft and the C axis:

[0215] Judgment 6.1: When the value of ΔC is less than the allowable precision value, it can be considered that the coaxiality between the main shaft and the C axis meets the requirements.

[0216] Judgment 6.2: When the value of ΔC is greater than or equal to the allowable precision value, it is necessary to re-detect the precise error of the coaxiality between the main shaft and the C axis, operate according to step S1 in this embodiment, input the detection program and execute it, set the machine tool feed rate to 100%, and the feed rate cannot be adjusted randomly during the detection process. The specific program is as follows:

[0217] (36) Execute G500 TRAORI; activate the machine tool coordinate system and the five-axis linkage function;

[0218] (37) Execute G01 F500; set the speed;

[0219] (38) Execute A0 C0, G4 F3; move to the set angle θ 9 and stop for 3 seconds, record the dial indicator reading X 11；

[0220] (39) Execute A0 C90, G4 F3; move to the set angle θ 10 and stop for 3 seconds, record the dial indicator reading X 12；

[0221] (40) Execute A0 C180, G4 F3; move to the set angle θ 11 and stop for 3 seconds, record the dial indicator reading X 13；

[0222] (41) Execute A0 C270, G4 F3; move to the set angle θ 12 and stop for 3 seconds, record the dial indicator reading X 14。

[0223] Further, calculate the deviation λ of the coaxiality between the main shaft and the C axis in the X direction 3 = X 11 - X 13 , then the deviation compensation value λ of the coaxiality between the main shaft and the C axis in the X direction 4 = λ 3 / 2; calculate the deviation λ of the coaxiality between the main shaft and the C axis in the Y direction 5 = X 12 - X 14 , then the deviation compensation value λ of the coaxiality between the main shaft and the C axis in the Y direction 6 = λ 5 / 2; the compensation value λ4 and λ 6 are respectively calculated with their corresponding original system parameter compensation values, and the calculated new values are compensated back to their respective original system parameters again; after the compensation is completed, the procedures (30), (31), (32), (33), (34), and (35) in step S3 of this embodiment need to be executed again to detect and calculate the values of λ 3 and λ 5 until the values of λ 3 and λ 5 are less than the precision-permitted values.

[0224] Furthermore, after the compensation is completed, steps S1 to S3 in the above-mentioned embodiment 2 should be executed again to ensure that the X-direction error of the RTCP precision meets the requirements.

[0225] Embodiment 3

[0226] Based on embodiment 2, this embodiment further explains the Y-direction error for detecting the RTCP precision in step four, and the operation steps are as follows:

[0227] Step S1: Execute the program: G01 F500 A0 C0 M2 to make the A / C axes at the zero position, adjust the posture of the dial indicator so that the pointer faces the positive Y direction of the machine tool, as Figure 1 shown; use the handwheel to move the machine tool so that the top sphere of the ball probe contacts the pointer of the dial indicator, move the X axis in the positive and negative directions to find the highest point of the ball in the X direction; move the Z axis in the positive and negative directions to find the highest point of the ball in the Z direction; move the Y axis in the positive and negative directions to make the sphere contact the pointer again and make the dial indicator press the table by 0.2 mm, and rotate the dial of the dial indicator to make the pointer point to zero.

[0228] Step S2: Perform the detection according to step S2 of the above-mentioned embodiment 2 and record the eight set angles θ and the dial indicator readings Y. The movement trajectory is as Figure 5 shown, and the corresponding relationship between each angle movement combination and the corresponding reading is shown in Table 3 below:

[0229] Table 3 Corresponding relationship between each angle movement combination and the dial indicator reading

[0230]

[0231] Furthermore, according to the values of Y 1 ~Y 8 detected in step S2 of this embodiment, and perform a first-level judgment on three possible Y-value situations to calculate the RTCP precision situation △Y:

[0232] Judgment 1.1: When all Y values are positive, △Y = Y max , Y max = [Y 1 ~Y8 max；

[0233] Judgment 1.2: When all Y values are negative, △Y = |Y min |, Y max = [Y 1 ~Y 8 max；

[0234] Judgment 1.3: When Y values are both positive and negative, △Y = Y max -Y min , Y max = [Y 1 ~Y 8 max , Y max = [Y 1 ~Y 8 max。

[0235] Further, perform a second-level judgment based on the calculated RTCP accuracy status △Y:

[0236] Judgment 2.1: When the value of △Y is less than the allowable accuracy value, it can be considered that the Y-direction error of RTCP accuracy meets the requirements.

[0237] Judgment 2.2: When the value of △Y is greater than or equal to the allowable accuracy value, it can be considered that the Z-direction error and Y-direction error of RTCP accuracy are affected when compensating for the X-direction error of RTCP accuracy. Therefore, it is necessary to re-detect and compensate for the Z and X-direction errors of RTCP accuracy until the X, Y, and Z-direction errors of RTCP accuracy all meet the requirements.​​​​

Claims

1. A method for detecting and compensating RTCP accuracy of a CNC machine tool, characterized in that: The steps include: Step S1: Install the ball head check rod on the machine tool spindle, and input the length of the ball head check rod into the CNC machine tool; Step S2: Set up the dial indicator and adjust the dial indicator posture so that the indicator needle faces the Z positive direction of the machine tool, manually operate the machine tool so that the indicator needle contacts the highest point of the ball head, and rotate the dial of the dial indicator so that the pointer points to the zero position; by executing a fixed NC detection program, detect the Z-direction error of the RTCP accuracy and evaluate the RTCP accuracy status. If the requirements are met, proceed to the next accuracy detection; if the requirements are not met, it is necessary to detect and compensate for the accuracy errors of each sub-item until the Z-direction error of the RTCP accuracy meets the requirements; Step S3: Set up the dial indicator and adjust the dial indicator posture so that the indicator needle faces the positive direction of the machine tool X, manually operate the machine tool so that the indicator needle contacts the highest point of the ball head, and rotate the dial of the dial indicator so that the pointer points to the zero position; by executing a fixed NC detection program, detect the X-direction error of the RTCP accuracy and evaluate the RTCP accuracy status. If the requirements are met, proceed to the next accuracy detection; if the requirements are not met, it is necessary to detect and compensate for the accuracy errors of each sub-item until the X-direction error of the RTCP accuracy meets the requirements; Step S4: Set up the dial indicator and adjust the dial indicator posture so that the indicator needle faces the positive direction of the machine tool Y, manually operate the machine tool so that the indicator needle contacts the highest point of the ball head, and rotate the dial of the dial indicator so that the pointer points to the zero position; by executing a fixed NC detection program, detect the Y-direction error of the RTCP accuracy and evaluate the RTCP accuracy status. If the requirements are met, the detection and compensation are completed; if the requirements are not met, re-detect and compensate the X and Z-direction errors of the RTCP accuracy until the errors in the three directions of X, Y, and Z of the RTCP accuracy meet the requirements; In step S2, the Z-direction error of the RTCP accuracy is detected by executing a fixed NC detection program, including: when the TRAORI instruction is turned on, the machine tool moves to 8 compound angles θ formed by the combination of the swing axis A axis and the rotation axis C axis in sequence, and records the dial indicator values ​​Z1 to Z8 at each compound angle, wherein the angle of the A axis is selected as 90° and -90°, and the angle of the C axis is selected as 0°, 90°, 180°, and 270°; In step S2, the Z-direction error of the RTCP accuracy is detected by executing a fixed NC detection program, including: performing a first-level judgment on three possible Z value conditions according to the values ​​of Z1 to Z8, and calculating the RTCP accuracy △Z: Judgment 1.1: When Z1~Z8 are all positive, △Z=Z max , Z max =[Z1~Z8] max ; Judgment 1.2: When Z1~Z8 are all negative, △Z=|Z min |, Z min =[Z1~Z8] min ; Judgment 1.3: When Z1~Z8 are both positive and negative, △Z=Z max -Z min , Z max =[Z1~Z8] max , Z min =[Z1~Z8] min ; In step S2, evaluating the RTCP accuracy status includes performing a second level judgment based on the calculated RTCP accuracy status ΔZ: Judgment 2.1: When the value of △Z is less than the allowable value of accuracy, the Z-direction error of RTCP accuracy meets the requirement; Judgment 2.2: When the value of △Z is greater than or equal to the allowable value of accuracy, the Z-direction error of RTCP accuracy does not meet the requirements. It is necessary to calculate and compensate for the sub-item errors that make up the RTCP accuracy. The sub-item errors include the deviation between the spindle and the A-axis in the Y direction, the deviation from the spindle end face to the A-axis rotation center, and the C-axis rotation plane error. In judgment 2.2, the calculation and compensation of the various errors that make up the RTCP accuracy include: According to the dial indicator values ​​Z1 and Z5 measured when the composite angles are A-axis 90° / C-axis 0° and A-axis -90° / C-axis 0°, the third-level judgment is performed on the three possible Z value conditions, thereby calculating the deviation between the spindle and the A-axis in the Y direction and the deviation from the spindle end face to the A-axis rotation center: Judgment 3.1: When Z1 and Z5 are both positive or both positive and negative, the deviation between the spindle and the A axis in the Y direction λ1=(Z max -Z min ) / 2, the deviation from the spindle end face to the A-axis rotation center λ2=Z max -(Z max -Z min ) / 2, Z max =[Z1,Z5] max , Z min =[Z1,Z5] min ; Judgment 3.2: When Z1 and Z5 are both negative, calculate the deviation between the spindle and the A axis in the Y direction λ1=(Z min -Z max ) / 2, calculate the deviation λ2=Z min -(Z min -Z max ) / 2, Z max =[Z1,Z5] max , Z min =[Z1,Z5] min ; Then, according to the calculated values ​​of λ1 and λ2, the fourth level judgment is performed: Judgment 4.1: When the values ​​of |λ1| and |λ2| are less than the allowed accuracy values, the sub-item meets the requirement; Judgment 4.2: When the values ​​of |λ1| and |λ2| are greater than or equal to the permissible accuracy values, the deviations λ1 and λ2 are respectively calculated with their corresponding original system parameter compensation values, and the calculated new values ​​are compensated to their respective original system parameters again; after the compensation is completed, the dial indicator values ​​Z1 and Z5 need to be checked again, and the above third and fourth level judgments are performed in turn until the values ​​of |λ1| and |λ2| are less than the permissible accuracy values.

2. A method for detecting and compensating RTCP accuracy of a numerically controlled machine tool as claimed in claim 1, characterized in that: In judgment 2.2, the calculation and compensation of the various errors that make up the RTCP accuracy include: According to the dial indicator values ​​Z1, Z2, Z3, Z4 measured when the A axis is 90° or the dial indicator values ​​Z5, Z6, Z7, Z8 measured when the A axis is -90°, the fifth level judgment is made on the three possible Z value conditions, and the C axis rotation plane error △C is calculated; Judgment 5.1: When the Z value is positive, △C=Z max , Z max =[Z1~Z4] max or Z max =[Z5~Z8] max ; Judgment 5.2: When the Z values ​​are all negative, △C=|Z min |, Z min The value is determined by the area selected in the above judgment 5.

1. If the selected area is [Z1~Z4], then Z min =[Z1~Z4] min ; If the selected area is [Z5~Z8], then Z min =[Z5~Z8] min ; Judgment 5.3: When the Z value is both positive and negative, △C=Z max -Z min , Z max and Z min The value is determined by the area selected in the above judgment 5.

1. If the selected area is [Z1~Z4], then Z max =[Z1~Z4] max , Z min =[Z1~Z4] min ; If the selected area is [Z5~Z8], then Z max =[Z5~Z8] max , Z min =[Z5~Z8] min ; Then, the sixth level judgment is performed based on the calculated C-axis rotation plane error △C: Judgment 6.1: When the value of △C is less than the allowable value of accuracy, the C-axis rotation plane meets the requirements; Judgment 6.2: When the value of △C is greater than or equal to the accuracy allowable value, it is necessary to re-test the precise error of the rotating plane. Perform manual table alignment according to step S2, enter the test program and execute it. The machine tool feed rate is set to 100%. The rate cannot be adjusted arbitrarily during the test. The test procedure is as follows: Execute G500 TRAORI; activate the machine tool coordinate system and five-axis linkage function; Execute G01 F500; set the moving speed; Execute A90 C0, M0; move to the set angle θ9, rotate the dial of the dial indicator so that the pointer points to zero, and record the dial indicator reading Z9; Execute TRAFOOF to turn off the five-axis linkage function; Execute A90 C90, M0; move to the set angle θ 10 , use the hand wheel to move the X-axis and Y-axis, find the high point of the sphere in the X and Y directions again, and record the dial indicator reading Z 10 ; Execute A90 C180, M0; move to the set angle θ 11 , use the hand wheel to move the X-axis and Y-axis, find the high point of the sphere in the X and Y directions again, and record the dial indicator reading Z 11 ; Execute A90 C270, M0; move to the set angle θ 12 , use the hand wheel to move the X-axis and Y-axis, find the high point of the sphere in the X and Y directions again, and record the dial indicator reading Z 12 ; Then use the dial indicator readings Z9 and Z 10 , Z 11 , Z 12 The value is reversely superimposed and compensated, and the sag compensation function of the machine tool is used to use the Z axis to compensate the C axis rotation plane; After the compensation is completed, step S2 is executed again to ensure that the Z-direction error of the RTCP accuracy meets the requirements.

3. A method for detecting and compensating RTCP accuracy of a numerically controlled machine tool as claimed in claim 1, characterized in that: In step S3, the NC detection program of the X-axis error detection method of RTCP accuracy means that when the TRAORI instruction is turned on, the machine tool moves to 8 compound angles θ formed by the combination of the swing axis A axis and the rotation axis C axis, and records the dial indicator values ​​X1~X8 at each compound angle; at the same time, the angle of the A axis is selected as 45° and -45°, and the angle of the C axis is selected as 0°, 90°, 180°, and 270°.

4. A method for detecting and compensating RTCP accuracy of a numerically controlled machine tool as claimed in claim 3, characterized in that: In step S3, the X-direction error of the RTCP accuracy is detected by executing a fixed NC detection program, including: According to the values ​​of X1 to X8, the first-level judgment is made on the three possible X value conditions, and the RTCP accuracy △X is calculated accordingly: Judgment 1.1: When X1~X8 are all positive, △X=X max , X max =[X1~X8] max ; Judgment 1.2: When X1~X8 are all negative, △X=|X min |, X min =[X1~X8] min ; Judgment 1.3: When X1~X8 are both positive and negative, △X=X max -X min , X max =[X1~X8] max , X min =[X1~X8] min ; Then, the second level judgment is performed according to the calculated RTCP accuracy status △X: Judgment 2.1: When the value of △X is less than the allowed value of accuracy, the X-direction error of RTCP accuracy meets the requirement; Judgment 2.2: When the value of △X is greater than or equal to the allowable value of accuracy, the X-axis error of the RTCP accuracy does not meet the requirements. It is necessary to calculate the errors that make up the RTCP accuracy and compensate for them. The errors include the A-axis rotation plane error and the coaxiality error between the spindle and the C-axis.

5. A method for detecting and compensating RTCP accuracy of a numerically controlled machine tool as claimed in claim 4, characterized in that: In judgment 2.2, the errors of each component of RTCP accuracy are calculated and compensated, including: The third level judgment is performed according to the values ​​of X1 and X5 measured when the composite angles are A-axis 45° / C-axis 0° and A-axis -45° / C-axis 0°, respectively. The judgment method is consistent with the principle of the first level judgment method to calculate the A-axis rotation plane error △A; Then, the fourth level judgment is performed based on the calculated A-axis rotation plane error △A: Judgement 4.1: judge whether the value of △A is less than the allowable value of accuracy. When the value of △A is less than the allowable value of accuracy, the A-axis rotation plane meets the requirements; Judgment 4.2: When the value of △A is greater than or equal to the accuracy allowable value, it is necessary to re-check the precise error of the rotating plane. Perform manual table alignment according to step S3, then enter the detection program and execute it. The machine tool feed rate is set to 100%. The rate cannot be adjusted arbitrarily during the detection process. The specific procedures are as follows: Execute G500 TRAFOOF; activate the machine tool coordinate system and turn off the five-axis linkage function; Execute G01 F500; set the moving speed; Execute A-90 C0, M0; move to the set angle θ9, use the handwheel to move the Y and Z axes, find the high points of the sphere in the Y and Z directions again, and record the dial indicator reading X9; move Z to a safe point; Execute A-45 C0, M0; move to the set angle θ 10 , use the hand wheel to move the Y and Z axes, find the high points of the sphere in the Y and Z directions again, and record the dial indicator reading X 10 ;Move Z to a safe point; Execute A45 C0, M0; move to the set angle θ 11 , use the hand wheel to move the Y and Z axes, find the high points of the sphere in the Y and Z directions again, and record the dial indicator reading X 11 ;Move Z to a safe point; Execute A90 C0, M0; move to the set angle θ 12 , use the hand wheel to move the X-axis and Y-axis, find the high point of the sphere in the Y and Z directions again, and record the dial indicator reading X 12 ;Move Z to a safe point; Then change the dial indicator readings to X9, X 10 , X 11 , X 12 The value of is reversed and superimposed for compensation, and the sag compensation function of the machine tool is used to use the X-axis to compensate the A-axis rotation plane; After the compensation is completed, the dial indicator values ​​X1 and X5 are checked again, and the third and fourth level judgments are performed in sequence until the value of △A is less than the accuracy allowable value.

6. A method for detecting and compensating RTCP accuracy of a numerically controlled machine tool as claimed in claim 4, characterized in that: In judgment 2.2, the errors of each component of RTCP accuracy are calculated and compensated, including: According to the values ​​of X1, X2, X3, and X4 measured when the A axis is 45° or the values ​​of X5, X6, X7, and X8 measured when the A axis is -45°, the fifth level judgment is performed to calculate the coaxiality error △C between the spindle and the C axis: Judgment 5.1: When all X values ​​are positive, △C=X max , X max =[X1~X4] max or X max =[X5~X8] max ; Judgment 5.2: When all X values ​​are negative, △C = |X min |, Z min The value is determined by the area selected in the above judgment 5.

1. If the selected area is [X1~X4], then X min =[X1~X4] min ; If the selected area is [X5~X8], then X min =[X5~X8] min ; Judgement 5.3: When the value of X is both positive and negative, △C=X max -X min , X max and X min The value is determined by the area selected in the above judgment 5.

1. If the selected area is [X1~X4], then X max =[X1~X4] max , X min =[X1~X4] min ; If the selected area is [X5~X8], then X max =[X5~X8] max , X min =[X5~X8] min ; Perform the sixth level judgment based on the calculated coaxiality error △C between the spindle and the C axis: Judgment 6.1: When the value of △C is less than the allowable value of accuracy, the coaxiality between the spindle and the C axis meets the requirements; Judgment 6.2: When the value of △C is greater than or equal to the allowable value of accuracy, it is necessary to re-check the precise error of the coaxiality between the spindle and the C axis. Perform manual table alignment according to step S3, then enter the detection program and execute it. The machine tool feed rate is set to 100%. The rate cannot be adjusted arbitrarily during the detection process. The specific procedures are as follows: Execute G500 TRAORI; activate the machine tool coordinate system and five-axis linkage function; Execute G01 F500; set speed; Execute A0 C0, G4 F3; move to the set angle θ9, record the dial indicator reading X 11 ; Execute A0 C90, G4 F3; move to the set angle θ 10 , record the dial indicator reading X 12 ; Execute A0 C180, G4 F3; move to the set angle θ 11 , record the dial indicator reading X 13 ; Execute A0 C270, G4 F3; move to the set angle θ 12 , record the dial indicator reading X 14 ; Calculate the coaxiality deviation between the spindle and the C axis in the X direction λ3=X 11 -X 13 , then the coaxiality compensation value of the spindle and the C axis in the X direction is λ4=λ3 / 2; calculate the coaxiality deviation of the spindle and the C axis in the Y direction is λ5=X 12 -X 14 , then the Y-direction deviation compensation value of the coaxiality between the spindle and the C axis is λ6=λ5 / 2; the compensation values ​​λ4 and λ6 are calculated with their corresponding original system parameter compensation values ​​respectively, and the calculated new values ​​are compensated to their respective original system parameters again; after the compensation is completed, the detection procedure in judgment 4.2 needs to be executed again to detect and calculate the values ​​of λ3 and λ5 until the values ​​of λ3 and λ5 are less than the accuracy allowable values; After the compensation is completed, the above step S3 is performed again to ensure that the X-direction error of the RTCP accuracy meets the requirements.

7. A method for detecting and compensating RTCP accuracy of a numerically controlled machine tool as claimed in claim 1, characterized in that: The NC detection procedure in step S4 is consistent with the procedure in step S2, and a total of 8 composite angles θ1 to θ8 are detected, and the corresponding dial indicator readings are Y1 to Y8; the RTCP accuracy △Y is calculated based on the values ​​of Y1 to Y8; Judgment 1.1: When all Y values ​​are positive, △Y=Y max , Y max =[Y1~Y8] max ; Judgment 1.2: When all Y values ​​are negative, △Y=|Y min |, Y max =[Y1~Y8] max ; Judgment 1.3: When the value of Y is both positive and negative, △Y=Y max -Y min , Y max =[Y1~Y8] max , Y max =[Y1~Y8] max ; Then, the second level judgment is performed according to the calculated RTCP accuracy status △Y: Judgment 2.1: When the value of △Y is less than the allowed value of accuracy, the Y-direction error of RTCP accuracy meets the requirement; Judgment 2.2: When the value of △Y is greater than or equal to the allowed value of accuracy, it means that the Z-direction error and Y-direction error of RTCP accuracy are affected when performing the X-direction error compensation of RTCP accuracy. Therefore, it is necessary to re-detect and compensate the Z and X-direction errors of RTCP accuracy until the errors in the three directions of X, Y, and Z of RTCP accuracy meet the requirements.

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