RTCP accuracy measurement and compensation method for computer numerical control machine tool

Abstract

The present invention belongs to the field of computer numerical control (NC) machine tool control. Disclosed is an RTCP accuracy measurement and compensation method for a computer NC machine tool. The method comprises: mounting a ball-end test bar on a machine tool spindle; setting up a dial indicator and adjusting the orientation of the dial indicator, such that a plunger points toward a positive Z-direction of a machine tool, manually operating the machine tool to bring the plunger into contact with the highest point of a ball end, and rotating a bezel of the dial indicator to set a pointer to zero; executing a fixed NC measurement program to measure a Z-direction error, and evaluating an accuracy status; if requirements are met, performing the next accuracy measurement; if the requirements are not met, measuring and compensating for individual component accuracy errors until the Z-direction error meets the requirements; and using the same method to sequentially measure an X-direction error and a Y-direction error until the X-direction error, the Y-direction error and the Z-direction error all meet the requirements. In the present invention, actual deviations of RTCP accuracy in three spatial directions can be measured, such that the accuracy status of a machine tool can be accurately reflected; and error compensation is performed by means of a built-in compensation function of a system.

Description

A method for RTCP accuracy detection and compensation in CNC machine tools Technical Field

[0001] This invention relates to the field of RTCP precision control for CNC machine tools, and specifically to a method for RTCP precision detection and compensation for CNC machine tools. Background Technology

[0002] RTCP accuracy is mainly used to evaluate the overall accuracy of five-axis CNC machine tools. It is one of the most important accuracy parameters of five-axis CNC machine tools, and its accuracy directly affects the machining quality of parts. However, existing technologies have blind spots in RTCP accuracy detection and compensation, and cannot fully reflect the true accuracy of the machine tool.

[0003] Existing technologies, such as the journals "Research on RTCP Calibration Algorithm for HNC-8 Five-Axis CNC Machine Tools" and "RTCP Accuracy Detection and Correction Method for Five-Axis Machining Centers" and the patent "A Probe-Based RTCP Accuracy Calibration Method for CA-Type Five-Axis CNC Machine Tools," all compensate for the Z-direction error of RTCP accuracy by detecting the vector deviation between the spindle axis and the axes of each swing or rotary axis. However, these technologies do not consider that the X and Y-direction errors of RTCP accuracy also have a direct impact on the machining quality of parts, and therefore cannot fully meet the RTCP accuracy debugging requirements of five-axis linkage CNC machine tools.

[0004] For example, patents titled "A Method for RTCP Calibration and Compensation of a Five-Axis CNC Machine Tool with a Double Swing Head Structure" and "Machine Tool Accuracy Compensation Method, Device, Storage Medium, and Electronic Equipment" both demonstrate that the aforementioned technical methods can detect the X, Y, and Z direction errors of RTCP accuracy. However, conventional systems, such as the Siemens 840D, do not have direct compensation parameters for the three directions of RTCP accuracy errors. 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-mentioned technologies requires secondary development to achieve, which undoubtedly increases the technical difficulty of error compensation.

[0005] In view of this, the present invention proposes a method for RTCP accuracy detection and compensation of CNC machine tools. Summary of the Invention

[0006] The purpose of this invention is to address the problem that existing technologies for RTCP accuracy detection and compensation have blind spots, failing to fully reflect the true accuracy of the machine tool. This invention proposes a method for RTCP accuracy detection and compensation in CNC machine tools. This method can detect the true deviation of RTCP accuracy in three spatial directions and perform error compensation based on the machine tool's built-in compensation function, effectively solving the problem of RTCP accuracy debugging.

[0007] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows:

[0008] A method for RTCP accuracy detection and compensation of CNC machine tools includes the following steps:

[0009] Step S1: Install the ball end gauge on the machine tool spindle and enter the length in the ball end gauge length field of the tool list;

[0010] Step S2: Set up the dial indicator and adjust its attitude so that the pointer points towards 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. Rotate the dial indicator dial to make the pointer point to zero. By executing a fixed NC inspection program, detect the Z-axis error of the RTCP accuracy and evaluate the RTCP accuracy status. If it meets the requirements, proceed to the next accuracy test. If it does not meet the requirements, it is necessary to detect and compensate for the accuracy errors of each item until the Z-axis error of the RTCP accuracy meets the requirements.

[0011] Step S3: Set up the dial indicator and adjust its attitude so that the pointer points towards 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. Rotate the dial indicator dial to make the pointer point to zero. By executing a fixed NC inspection program, detect the X-axis error of the RTCP accuracy and evaluate the RTCP accuracy status. If it meets the requirements, proceed to the next accuracy test. If it does not meet the requirements, it is necessary to detect and compensate for the accuracy errors of each item until the X-axis error of the RTCP accuracy meets the requirements.

[0012] Step S4: Set up the dial indicator and adjust its attitude so that the pointer points towards 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. Rotate the dial indicator dial to make the pointer point to zero. By executing a fixed NC detection program, detect the Y-axis 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 for the X and Z-axis errors of the RTCP accuracy until the X, Y, and Z-axis errors of the RTCP accuracy all meet the requirements.

[0013] Preferably, in step S2, the Z-axis error of the RTCP accuracy is detected by executing a fixed NC detection program, including: with the TRAORI command enabled, the machine tool moves sequentially to eight composite angles θ formed by the combination of the swing axis A and the rotary axis C, and the dial gauge values ​​Z1 to Z8 are recorded at each composite 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°.

[0014] Preferably, in step S2, the Z-axis error of the RTCP accuracy is detected by executing a fixed NC detection program, including: making a first-level judgment on the three possible Z-value situations based on the values ​​of Z1 to Z8, and calculating the RTCP accuracy ΔZ.

[0015] Judgment 1.1: When Z1 to Z8 are all positive, ΔZ = Z max Z max =[Z1~Z8] max ;

[0016] Judgment 1.2: When Z1 to Z8 are all negative, △Z = |Z min |, Z min =[Z1~Z8] min ;

[0017] Judgment 1.3: When Z1 to Z8 can be either positive or negative, △Z = Z max -Z min Z max =[Z1~Z8] max Z min =[Z1~Z8] min .

[0018] Preferably, 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 precision allowable value, the Z-axis error of RTCP precision meets the requirements;

[0020] Judgment 2.2: When the value of △Z is greater than or equal to the accuracy allowable value, the Z-axis error of RTCP accuracy does not meet the requirements. It is necessary to calculate and compensate for each component error that makes up the RTCP accuracy. Each component error includes the deviation between the spindle and the A-axis in the Y direction, the deviation from the spindle end face to the rotation center of the A-axis, and the rotation plane error of the C-axis.

[0021] Preferably, in judgment 2.2, the calculation and compensation of the individual errors constituting the RTCP accuracy include:

[0022] Based on the dial gauge values ​​Z1 and Z5 measured when the combined angles are 90° A-axis / 0° C-axis and -90° A-axis / 0° C-axis respectively, a third-level judgment is made on the three possible Z value conditions, thereby calculating the deviation of the spindle from the A-axis in the Y direction and the deviation of the spindle end face from the rotation center of the A-axis:

[0023] Judgment 3.1: When both Z1 and Z5 are positive or both are negative, the deviation λ1 between the principal axis and the A-axis in the Y direction is (Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, Z9, Z1, Z1, Z2, Z9, Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, Z9, Z1, Z9, Z1, Z2, Z9, Z1, max -Z min) / 2, the deviation λ2 from the spindle end face to the rotation center of axis A is Z max -(Z max -Z min ) / 2, Z max =[Z1, Z5] max Z min =[Z1, Z5] min ;

[0024] Judgment 3.2: When both Z1 and Z5 are negative, calculate the deviation λ1 between the principal axis and the A-axis in the Y direction = (Z min -Z max ) / 2, calculate the deviation λ2=Z from the spindle end face to the rotation center of axis A. min -(Z min -Z max ) / 2, Z max =[Z1, Z5] max Z min =[Z1, Z5] min ;

[0025] Then, based on the calculated values ​​of λ1 and λ2, perform the fourth level of judgment:

[0026] Judgment 4.1: When the values ​​of |λ1| and |λ2| are less than the precision allowable value, this item meets the requirement;

[0027] Judgment 4.2: When the values ​​of |λ1| and |λ2| are greater than or equal to the permissible accuracy value, the deviations λ1 and λ2 are calculated with their respective original system parameter compensation values, and the calculated new values ​​are then compensated back into their respective original system parameters. After the compensation is completed, the dial gauge values ​​Z1 and Z5 need to be checked again, and the above third and fourth level judgments are executed in sequence until the values ​​of |λ1| and |λ2| are less than the permissible accuracy value.

[0028] Preferably, in judgment 2.2, the calculation and compensation of the individual errors constituting the RTCP accuracy include:

[0029] Based on the dial gauge values ​​Z1, Z2, Z3, Z4 measured when the A-axis is 90° or Z5, Z6, Z7, Z8 measured when the A-axis is -90°, a fifth-level judgment is made on the three possible Z value situations, and the C-axis rotation plane error △C is calculated.

[0030] Judgment 5.1: When all Z values ​​are positive, △C = Z max Z max =[Z1~Z4] max or Z max =[Z5~Z8] max ;

[0031] Judgment 5.2: When all Z values ​​are negative, △C = |Z min |, Z min The value is determined by the region selected in the above judgment 5.1. If the selected region is [Z1~Z4], then Z min =[Z1~Z4] min If the selected region is [Z5~Z8], then Z min =[Z5~Z8] min ;

[0032] Judgment 5.3: When Z can be either positive or negative, △C = Z max -Z min Z max and Z min The value is determined by the region selected in the above judgment 5.1. If the selected region is [Z1~Z4], then Z max =[Z1~Z4] max Z min =[Z1~Z4] min If the selected region is [Z5~Z8], then Z max =[Z5~Z8] max Z min =[Z5~Z8] min ;

[0033] Then, based on the calculated C-axis rotational plane error △C, perform the sixth level of judgment:

[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 accuracy value, the accuracy error of the rotating plane needs to be re-checked. Perform manual dialing operation according to step S2, input the detection program and execute it. Set the machine tool feed rate to 100%. The feed rate cannot be adjusted arbitrarily during the detection process. The detection program is as follows:

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

[0037] Execute G01 F500; Set movement speed;

[0038] Execute A90 C0, M0; move to the set angle θ9, rotate the dial indicator dial to make the pointer point to zero, and record the dial indicator reading Z9;

[0039] Run TRAFOOF to disable the five-axis linkage function;

[0040] Execute A90 C90, M0; move to the set angle θ 10Use the handwheel to move the X and Y axes, find the highest points of the sphere in the X and Y directions again, and record the dial gauge readings Z. 10 ;

[0041] Execute A90 C180, M0; move to the set angle θ 11 Use the handwheel to move the X and Y axes, find the highest points of the sphere in the X and Y directions again, and record the dial gauge readings Z. 11 ;

[0042] Execute A90 C270, M0; move to the set angle θ 12 Use the handwheel to move the X and Y axes, find the highest points of the sphere in the X and Y directions again, and record the dial gauge readings Z. 12 ;

[0043] Then, take the dial gauge readings Z9 and Z2 obtained from the testing procedure. 10 Z 11 Z 12 The values ​​are compensated by reverse superposition, and the machine tool sag compensation function is used to compensate the C-axis rotation plane using the Z-axis.

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

[0045] Preferably, in step S3, the NC detection program of the RTCP accuracy X-axis error detection method refers to, when the TRAORI command is enabled, the machine tool moves to the eight composite angles θ formed by the combination of the swing axis A and the rotary axis C, and records the dial gauge values ​​X1 to X8 at each composite 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°.

[0046] Preferably, in step S3, the X-axis error of the RTCP accuracy is detected by executing a fixed NC detection program, including:

[0047] Based on the values ​​of X1 to X8, a first-level judgment is made on the three possible X value scenarios, and the corresponding RTCP precision ΔX is calculated:

[0048] Judgment 1.1: When X1 to X8 are all positive values, △X = X max X max =[X1~X8] max ;

[0049] Judgment 1.2: When X1 to X8 are all negative, △X = |X min |, X min =[X1~X8] min ;

[0050] Judgment 1.3: When X1 to X8 can be either positive or negative, △X = X max -X min X max =[X1~X8] max X min =[X1~X8] min ;

[0051] Then, based on the calculated RTCP accuracy △X, a second-level judgment is performed:

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

[0053] Judgment 2.2: When the value of △X is greater than or equal to the accuracy allowable value, the X-axis error of RTCP accuracy does not meet the requirements. It is necessary to calculate and compensate for each component error that makes up the RTCP accuracy. Each component error includes the A-axis rotation plane error and the coaxiality error between the principal axis and the C-axis.

[0054] Preferably, in judgment 2.2, the calculation and compensation of the individual errors constituting the RTCP accuracy include:

[0055] The third-level judgment is performed based on the values ​​of X1 and X5 measured when the composite angle is 45° / C0° and -45° / C0° respectively. The judgment method is consistent with the principle of the first-level judgment method, in order to calculate the A-axis rotation plane error △A.

[0056] Then, based on the calculated rotational plane error △A along axis A, perform the fourth level of judgment:

[0057] Judgment 4.1: Determine whether the value of △A is less than the allowable precision value. When the value of △A is less than the allowable precision value, the A-axis rotation plane meets the requirements.

[0058] Judgment 4.2: When the value of △A is greater than or equal to the allowable accuracy value, the accuracy error of the rotating plane needs to be re-checked. Perform manual dialing operation according to step S3, then input and execute the detection program. Set the machine tool feed rate to 100%. The feed rate cannot be adjusted arbitrarily during the detection process. The specific procedure is as follows:

[0059] Execute G500 TRAFOOF; activate the machine tool coordinate system and disable the five-axis linkage function;

[0060] Execute G01 F500; Set movement speed;

[0061] Execute A-90 C0, M0; move to the set angle θ9, use the handwheel to move the Y and Z axes, find the highest point of the sphere in the Y and Z directions again, and record the dial gauge reading X9; 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, find the highest points of the sphere in the Y and Z directions again, and record the dial gauge readings X. 10 Move Z to a safe point;

[0063] Execute A45 C0, M0; move to the set angle θ 11 Use the handwheel to move the Y and Z axes, find the highest points of the sphere in the Y and Z directions again, and record the dial gauge readings X. 11 Move Z to a safe point;

[0064] Execute A90 C0, M0; move to the set angle θ 12 Use the handwheel to move the X and Y axes, find the highest points of the sphere in the Y and Z directions, and record the dial gauge readings X. 12 Move Z to a safe point;

[0065] Then X9 and X2 of the dial gauge readings. 10 X 11 X 12 The values ​​are compensated by reverse superposition, and the machine tool sag compensation function is used to compensate the A-axis rotation plane using the X-axis.

[0066] After compensation is completed, the dial gauge 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.

[0067] Preferably, in judgment 2.2, the calculation and compensation of the individual errors constituting the RTCP accuracy include:

[0068] Based on 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°, perform the fifth-level judgment to calculate the coaxiality error △C between the principal axis and the C-axis:

[0069] Judgment 5.1: When all values ​​of X are positive, △C = X max X max =[X1~X4] max or X max =[X5~X8] max ;

[0070] Judgment 5.2: When all values ​​of X are negative, △C = |X| min |, Z min The value is determined by the region selected in the above judgment 5.1. If the selected region is [X1~X4], then X min =[X1~X4] min If the selected region is [X5~X8], then X min =[X5~X8]min ;

[0071] Judgment 5.3: When X can have both positive and negative values, △C = X max -X min X max and X min The value is determined by the region selected in the above judgment 5.1. If the selected region is [X1~X4], then X max =[X1~X4] max X min =[X1~X4] min If the selected region is [X5~X8], then X max =[X5~X8] max X min =[X5~X8] min ;

[0072] Based on the calculated coaxiality error △C between the main spindle and the C-axis, perform the sixth-level judgment:

[0073] Judgment 6.1: When the value of △C is less than the allowable value, the coaxiality of the spindle 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, the coaxiality accuracy error between the spindle and the C-axis needs to be re-checked. Perform manual dialing operation according to step S3, then input and execute the detection program. Set the machine tool feed rate to 100%. The feed rate cannot be adjusted arbitrarily during the detection process. The specific procedure is as follows:

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

[0076] Execute G01 F500; Set speed;

[0077] Execute A0 C0, G4 F3; move to the set angle θ9, and record the dial gauge reading X. 11 ;

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

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

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

[0081] Calculate the coaxiality deviation of the spindle and C-axis in the X direction λ3=X 11 -X 13 Then, the coaxiality deviation compensation value between the spindle and the C-axis in the X direction is λ4 = λ3 / 2; calculate the coaxiality deviation between the spindle and the C-axis in the Y direction λ5 = X 12 -X 14 Then, the coaxiality of the spindle and the C-axis in the Y-direction deviation compensation value λ6 = λ5 / 2; calculate the compensation values ​​λ4 and λ6 with their respective original system parameter compensation values, and then compensate the new values ​​back into their respective original system parameters; 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 value;

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

[0083] Preferably, the NC detection program in step S4 is the same as the program in step S2, and a total of 8 composite angles θ1 to θ8 are detected, and the corresponding dial gauge readings are Y1 to Y8; the RTCP accuracy ΔY is calculated based on the values ​​of Y1 to Y8.

[0084] Judgment 1.1: When all Y values ​​are positive, ΔY = Y max Y max =[Y1~Y8] max ;

[0085] Judgment 1.2: When all Y values ​​are negative, ΔY = |Y| min |, Y max =[Y1~Y8] max ;

[0086] Judgment 1.3: When Y has both positive and negative values, ΔY = Y max -Y min Y max =[Y1~Y8] max Y max =[Y1~Y8] max ;

[0087] Then, based on the calculated RTCP accuracy △Y, a second-level judgment is performed:

[0088] Judgment 2.1: When the value of △Y is less than the precision allowable value, the Y-axis error of RTCP precision meets the requirements;

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

[0090] In summary, the present invention has the following advantages:

[0091] This invention sets up an RTCP accuracy detection program for a CA-type five-axis linkage CNC machine tool. The program detects the errors in the X, Y, and Z directions when the machine tool moves to the four quadrants of the machine tool space after the RTCP function is enabled. When the error exceeds a set threshold, the system systematically judges and detects the factors affecting the RTCP accuracy and compensates for the error through the system's built-in compensation function, thereby improving the reliability of RTCP accuracy detection and compensation. Attached Figure Description

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

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

[0094] Figure 3 is a schematic diagram of the Z-axis detection motion trajectory of the present invention;

[0095] Figure 4 is a schematic diagram of the X-axis detection motion trajectory of the present invention;

[0096] Figure 5 is a schematic diagram of the Y-axis detection motion trajectory of the present invention. Embodiments of the present invention

[0097] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the invention. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention.

[0098] Example 1

[0099] This embodiment provides a method for RTCP accuracy detection and compensation of CNC machine tools. This compensation method requires the following testing instruments: 1) dial indicator and indicator holder; 2) ball end gauge; 3) mandrel; the specific steps are as follows:

[0100] Step 1: Install the ball end gauge on the machine tool spindle. Enter the length L in the ball end gauge length field of the tool list. L=HR / 2, where H is the total length of the ball end gauge and R is the diameter of the ball at the top of the ball end gauge. The data of H and R can be obtained by measuring with a tool setter.

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

[0102] Step S1: Execute the program: G01 F500 A0 C0 M2, so that the A / C axis is at zero. Then, install the dial indicator and its stand on the worktable and adjust the dial indicator's orientation so that the pointer points towards the positive Z direction of the machine tool, as shown in Figure 1. Use the handwheel to move the machine tool so that the ball head at the top of the ball probe contacts the dial indicator pointer. Move the X-axis in both positive and negative directions to find the highest point of the ball head in the X direction. Move the Y-axis in both positive and negative directions to find the highest point of the ball head in the Y direction. Move the Z-axis in both positive and negative directions so that the ball re-contacts the pointer and the dial indicator presses down by 0.2 mm. Rotate the dial indicator dial to make the pointer point to zero.

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

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

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

[0106] (3) Execute A90 C0, G4 F3; move to the set angle θ1 and stop for 3 seconds, record the dial gauge reading Z1;

[0107] (4) Execute A90 C90, G4 F3; move to the set angle θ2 and stop for 3 seconds, record the dial gauge reading Z2;

[0108] (5) Execute A90 180, G4 F3; move to the set angle θ3 and stop for 3 seconds, record the dial gauge reading Z3;

[0109] (6) Execute A90 C270, G4 F3; move to the set angle θ4 and stop for 3 seconds, record the dial gauge reading Z4;

[0110] (7) Execute A-90 C0, G4 F3; move to the set angle θ5 and stop for 3 seconds, record the dial gauge reading Z5;

[0111] (8) Execute A-90 C90, G4 F3; move to the set angle θ6 and stop for 3 seconds, record the dial gauge reading Z6;

[0112] (9) Execute A-90 180, G4 F3; move to the set angle θ7 and stop for 3 seconds, record the dial gauge reading Z7;

[0113] (10) Execute A-90 C270, G4 F3; move to the set angle θ8 and stop for 3 seconds, record the dial gauge reading Z8;

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

[0115] The motion trajectory is shown in Figure 3. The correspondence between the motion combinations at various angles and the corresponding readings is as follows:

[0116] Z-axis error setting: Dial gauge reading: Angle θ1A90 C0Z1; Angle θ2A90 C90Z2; Angle θ3A90 C180Z3; Angle θ4A90 C270Z4; Angle θ5A-90 C0Z5; Angle θ6A-90 C90Z6; Angle θ7A-90 C180Z7; Angle θ8A-90 C270Z8

[0117] Step S3: Further, based on the values ​​of Z1 to Z8 detected in step S2 above, and performing a first-level judgment on the three possible Z value situations, calculate the RTCP accuracy status △Z:

[0118] Judgment 1.1: When all Z values ​​are positive, ΔZ = Z max Z max =[Z1~Z8] max ;

[0119] Judgment 1.2: When all Z values ​​are negative, ΔZ = |Z| min |, Z min =[Z1~Z8] min ;

[0120] Judgment 1.3: When Z can have both positive and negative values, ΔZ = Z max -Z min Z max =[Z1~Z8] max Z min =[Z1~Z8] min .

[0121] Further, based on the calculated RTCP accuracy △Z, a second-level judgment is performed:

[0122] Judgment 2.1: When the value of |△Z| is less than the allowable value for accuracy, the Z-axis error of RTCP accuracy can be considered to meet the requirements.

[0123] Judgment 2.2: When the value of |△Z| is greater than or equal to the accuracy allowable value, it can be considered that the Z-axis error of RTCP accuracy does not meet the requirements. It is necessary to calculate and compensate for each component error that makes up the RTCP accuracy. Each component error includes the deviation between the spindle and the A-axis in the Y direction, the deviation from the spindle end face to the rotation center of the A-axis, and the rotation plane error of the C-axis.

[0124] Based on the values ​​of Z1 and Z5, and after a third-level judgment on the three possible Z value conditions, the deviation between the spindle and the A-axis in the Y direction and the deviation from the spindle end face to the rotation center of the A-axis are calculated.

[0125] Judgment 3.1: When both Z1 and Z5 are positive or both are negative, calculate the deviation λ1 between the principal axis and the A-axis in the Y direction = (Z1 + Z5 + Z6) / Z7. max -Z min ) / 2, calculate the deviation λ2=Z from the spindle end face to the rotation center of axis A. max -(Z max -Z min ) / 2, Z max =[Z1, Z5] max Z min =[Z1, Z5] min ;

[0126] Judgment 3.2: When both Z1 and Z5 are negative, calculate the deviation λ1 between the principal axis and the A-axis in the Y direction = (Z min -Z max ) / 2, calculate the deviation λ2=Z from the spindle end face to the rotation center of axis A. min -(Z min -Z max ) / 2, Z max =[Z1, Z5] max Z min =[Z1, Z5] min ;

[0127] Based on the calculated values ​​of λ1 and λ2, a fourth-level judgment is then performed:

[0128] Judgment 4.1: When the values ​​of |λ1| and |λ2| are less than the allowable precision values, the sub-item can be considered to meet the requirements.

[0129] Judgment 4.2: When the values ​​of |λ1| and |λ2| are greater than or equal to the permissible accuracy value, the deviations λ1 and λ2 need to be calculated with their respective original system parameter compensation values, and the calculated new values ​​are then compensated 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 and fourth level judgments are executed in sequence until the values ​​of |λ1| and |λ2| are less than the permissible accuracy value.

[0130] Further, based on the values ​​of Z1, Z2, Z3, Z4 or Z5, Z6, Z7, Z8, and a fifth-level judgment is made on the three possible Z value situations to evaluate the C-axis rotational plane error △C.

[0131] Judgment 5.1: When all Z values ​​are positive, △C = Z maxZ max =[Z1~Z4] max or Z max =[Z5~Z8] max

[0132] Judgment 5.2: When all Z values ​​are negative, △C = |Z min |, Z min The value is determined by the region selected in the above judgment 5.1. If the selected region is [Z1~Z4], then Z min =[Z1~Z4] min If the selected region is [Z5~Z8], then Z min =[Z5~Z8] min

[0133] Judgment 5.3: When Z can be either positive or negative, △C = Z max -Z min Z max and Z min The value is determined by the region selected in the above judgment 5.1. If the selected region is [Z1~Z4], then Z max =[Z1~Z4] max Z min =[Z1~Z4] min If the selected region is [Z5~Z8], then Z max =[Z5~Z8] max Z min =[Z5~Z8] min

[0134] Further, based on the calculated C-axis rotational plane error △C, a sixth-level judgment is performed:

[0135] Judgment 6.1: When the value of |△C| is less than the allowable value, the C-axis rotation plane can be considered to meet the requirements.

[0136] Judgment 6.2: When the value of |△C| is greater than or equal to the permissible accuracy value, the precision error of the rotating plane needs to be re-checked. Follow the steps in S1 above, input the detection program and execute it. Set the machine tool feed rate to 100%. The feed rate cannot be adjusted arbitrarily during the detection process. The specific procedure is as follows:

[0137] (12) Execute G500 TRAORI; activate the machine tool coordinate system and five-axis linkage function;

[0138] (13) Execute G01 F500; set the movement speed;

[0139] (14) Execute A90 C0, M0; move to the set angle θ9, rotate the dial indicator to make the pointer point to zero, and record the dial indicator reading Z9;

[0140] (15) Execute TRAFOOF to disable the five-axis linkage function;

[0141] (16) Execute A90 C90, M0; move to the set angle θ 10 Use the handwheel to move the X and Y axes, find the highest points of the sphere in the X and Y directions again, and record the dial gauge readings Z. 10 ;

[0142] (17) Execute A90 C180, M0; move to the set angle θ 11 Use the handwheel to move the X and Y axes, find the highest points of the sphere in the X and Y directions again, and record the dial gauge readings Z. 11 ;

[0143] (18) Execute A90 C270, M0; move to the set angle θ 12 Use the handwheel to move the X and Y axes, find the highest points of the sphere in the X and Y directions again, and record the dial gauge readings Z. 12 .

[0144] Further, the dial gauge readings Z9 and Z 10 Z 11 Z 12 The values ​​are compensated by reverse superposition, and the machine tool sag compensation function is used to compensate the C-axis rotation plane using the Z-axis. The compensation program is as follows:

[0145] ﹩AN_CEC[5,0]= -Z9; the compensation value when A90 C0;

[0146] ﹩AN_CEC[5, 90]=-Z 10 Compensation values ​​at A90 and C90;

[0147] ﹩AN_CEC[5, 180]=-Z 11 Compensation value at A90 C180;

[0148] ﹩AN_CEC[5, 270]=-Z 12 Compensation value at A90 C270;

[0149] ﹩AN_CEC_INPUT[5]=(Z;The input axis is the Z-axis;

[0150] ﹩AN_CEC_OUTPUT[5]=(C; The output axis is the C axis;

[0151] ﹩AN_CEC_STEP[5]=90; the compensation interval is 90 degrees;

[0152] ﹩AN_CEC_MIN[5]=0; The starting point is C0;

[0153] ﹩AN_CEC_MAX[5]=270; the endpoint is C270.

[0154] After further compensation is completed, steps S1 to S3 above should be executed again to ensure that the Z-axis error of RTCP accuracy meets the requirements.

[0155] Step 3: Detect and compensate for the X-axis error in RTCP accuracy:

[0156] Set up the dial indicator and adjust its attitude so that the pointer points towards the positive X direction of the machine tool. Manually operate the machine tool to bring the pointer into contact with the highest point of the ball head. Rotate the dial indicator dial to make the pointer point to zero. By executing a fixed NC inspection program, detect the X-axis error of the RTCP accuracy and evaluate the RTCP accuracy status. If it meets the requirements, proceed to the next accuracy test. If it does not meet the requirements, it is necessary to detect and compensate for the accuracy errors of each item until the X-axis error of the RTCP accuracy meets the requirements.

[0157] Step 4: Detect and compensate for the Y-axis error in RTCP accuracy:

[0158] Set up the dial indicator and adjust its attitude so that the pointer points towards the positive Y direction of the machine tool. Manually operate the machine tool to bring the pointer into contact with the highest point of the ball head. Rotate the dial indicator dial to make the pointer point to zero. Execute a fixed NC testing program to detect the Y-axis error of the RTCP accuracy and evaluate the RTCP accuracy status. If the requirements are met, the detection and compensation are complete. If the requirements are not met, the X and Z-axis errors of the RTCP accuracy need to be re-detected and compensated until the X, Y, and Z-axis errors of the RTCP accuracy all meet the requirements.

[0159] Example 2

[0160] Based on Example 1, this example further illustrates the detection and compensation of the X-axis error in RTCP accuracy. The operation steps are as follows:

[0161] Step S1: Execute the program: G01 F500 A0 C0 M2, so that the A / C axis is at zero position. Adjust the dial indicator posture so that the indicator needle is facing the positive X direction of the machine tool, as shown in Figure 1. Use the handwheel to move the machine tool so that the ball at the top of the ball head probe contacts the dial indicator needle. Move the Y axis in both positive and negative directions to find the highest point of the ball head in the Y direction. Move the Z axis in both positive and negative directions to find the highest point of the ball head in the Z direction. Move the X axis in both positive and negative directions so that the ball re-contacts the needle and the dial indicator is pressed down by 0.2 mm. Rotate the dial indicator dial so that the pointer points to zero.

[0162] Step S2: Input and execute the RTCP detection program. Set the machine tool feed rate to 100%. Do not adjust the feed rate arbitrarily during the detection process. The specific program is as follows:

[0163] (19) Execute G500 TRAORI; activate the machine tool coordinate system and five-axis linkage function;

[0164] (20) Execute G01 F500; set the movement speed;

[0165] (21) Execute A45 C0, G4 F3; move to the set angle θ1 and stop for 3 seconds, record the dial gauge reading X1;

[0166] (22) Execute A45 C90, G4 F3; move to the set angle θ2 and stop for 3 seconds, record the dial gauge reading X2;

[0167] (23) Execute A45 180, G4 F3; move to the set angle θ3 and stop for 3 seconds, record the dial gauge reading X3;

[0168] (24) Execute A45 C270, G4 F3; move to the set angle θ4 and stop for 3 seconds, record the dial gauge reading X4;

[0169] (25) Execute A-45 C0, G4 F3; move to the set angle θ5 and stop for 3 seconds, record the dial gauge reading X5;

[0170] (26) Execute A-45 C90, G4 F3; move to the set angle θ6 and stop for 3 seconds, record the dial gauge reading X6;

[0171] (27) Execute A-45 180, G4 F3; move to the set angle θ7 and stop for 3 seconds, record the dial gauge reading X7;

[0172] (28) Execute A-45 C270, G4 F3; move to the set angle θ8 and stop for 3 seconds, record the dial gauge reading X8;

[0173] (29) Execute A0 C0, M30, return to the zero position of the A / C axis and end the program.

[0174] The motion trajectory is shown in Figure 4. The correspondence between the motion combinations at various angles and the corresponding readings is as follows:

[0175] X-axis error setting angle dial gauge readings: First angle θ1 A45 C0X1; Second angle θ2 A45 C90X2; Third angle θ3 A45 C180X3; Fourth angle θ4 A45 C270X4; Fifth angle θ5 A-45 C0X5; Sixth angle θ6 A-45 C90X6; Seventh angle θ7 A-45 C180X7; Eighth angle θ8 A-45 C270X8

[0176] Step S3: Further, based on the values ​​of X1 to X8 detected in step S2 of this embodiment, and performing a first-level judgment on the three possible X value situations, the RTCP accuracy status △X is calculated:

[0177] Judgment 1.1: When all values ​​of X are positive, ΔX = X max X max =[X1~X8] max ;

[0178] Judgment 1.2: When all values ​​of X are negative, △X = |X| min |, X min =[X1~X8] min ;

[0179] Judgment 1.3: When X can have both positive and negative values, △X = X max -X min X max =[X1~X8] max X min =[X1~X8] min .

[0180] Further, based on the calculated RTCP accuracy △X, a second-level judgment is performed:

[0181] Judgment 2.1: When the value of |△X| is less than the precision allowable value, the X-axis error of RTCP precision can be considered to meet the requirements.

[0182] Judgment 2.2: When the value of |△X| is greater than or equal to the accuracy allowable value, it can be considered that the X-axis error of RTCP accuracy does not meet the requirements. It is necessary to calculate and compensate for each component error that makes up the RTCP accuracy. Each component error includes the A-axis rotation plane error and the coaxiality error between the principal axis and the C-axis.

[0183] Further, based on the values ​​of X1 and X5, and a third-level judgment is made on the three possible X value situations to evaluate the A-axis rotational plane error △A;

[0184] Judgment 3.1: When all values ​​of X are positive, △A = X max X max =[X1, X5] max ;

[0185] Judgment 3.2: When all values ​​of X are negative, △A = |X| min |, X min =[X1, X5] min ;

[0186] Judgment 3.3: When X can have both positive and negative values, △A = X max -X min Xmax =[X1, X5] max X min =[X1, X5] min .

[0187] Further, based on the calculated rotational plane error △A along the A-axis, a fourth-level judgment is performed:

[0188] Judgment 4.1: When the value of |△A| is less than the allowable value, the rotation plane of axis A can be considered to meet the requirements.

[0189] Judgment 4.2: When the value of |△A| is greater than or equal to the allowable accuracy value, the accuracy error of the rotating plane needs to be re-checked. Follow step S1 in Example 2 above, input the detection program and execute it. Set the machine tool feed rate to 100%. The feed rate cannot be adjusted arbitrarily during the detection process. The specific procedure is as follows:

[0190] (30) Execute G500 TRAFOOF; activate the machine tool coordinate system and disable the five-axis linkage function;

[0191] (31) Execute G01 F500; set the movement speed;

[0192] (32) Execute A-90 C0, M0; move to the set angle θ9, use the handwheel to move the Y and Z axes, find the high point of the ball in the Y and Z directions again, and record the dial gauge reading X9; move Z to the safe point;

[0193] (33) Execute A-45 C0, M0; move to the set angle θ 10 Use the handwheel to move the Y and Z axes, find the highest points of the sphere in the Y and Z directions again, and record the dial gauge readings X. 10 Move Z to a safe point;

[0194] (34) Execute A45 C0, M0; move to the set angle θ 11 Use the handwheel to move the Y and Z axes, find the highest points of the sphere in the Y and Z directions again, and record the dial gauge readings X. 11 Move Z to a safe point;

[0195] (35) Execute A90 C0, M0; move to the set angle θ 12 Use the handwheel to move the X and Y axes, find the highest points of the sphere in the Y and Z directions, and record the dial gauge readings X. 12 Move Z to a safe point.

[0196] Further, X9 and X... 10 X 11 X 12The values ​​are compensated by reverse superposition, and the machine tool sag compensation function is used to compensate the A-axis rotation plane using the X-axis. The compensation program is as follows:

[0197] ﹩AN_CEC[4, -90]=-X9; the compensation value when A-90 C0;

[0198] ﹩AN_CEC[4, -45]=-X 10 Compensation value at A-45 C0;

[0199] ﹩AN_CEC[4, 0]=0; the compensation value when A0 C0;

[0200] ﹩AN_CEC[4, 45]=-X 11 Compensation value at A45 C0;

[0201] ﹩AN_CEC[4, 90]=-X 12 Compensation value at A90 C0;

[0202] ﹩AN_CEC_INPUT[4]=(X;The input axis is the X-axis;

[0203] ﹩AN_CEC_OUTPUT[4]=(A; The output axis is the A axis;

[0204] ﹩AN_CEC_STEP[4]=45; the compensation interval is 45 degrees;

[0205] ﹩AN_CEC_MIN[4]=-90; The starting point is C-90;

[0206] ﹩AN_CEC_MAX[4]=90; The endpoint is C90.

[0207] After further compensation is completed, the procedures (19), (20), (21), and (25) in step S2 of this embodiment are executed again, and the third and fourth level judgments in this embodiment are executed in sequence until the value of △A is less than the precision allowable value.

[0208] Further, based on the values ​​of X1, X2, X3, X4 or X5, X6, X7, X8, and considering the three possible X value scenarios, a fifth-level judgment is made to evaluate the coaxiality error △C between the main axis and the C-axis.

[0209] Judgment 5.1: When all values ​​of X are positive, △C = X max X max =[X1~X4] max or X max =[X5~X8] max ;

[0210] Judgment 5.2: When all values ​​of X are negative, △C = |X| min |, Z min The value is determined by the region selected in the above judgment 5.1. If the selected region is [X1~X4], then X min =[X1~X4] min If the selected region is [X5~X8], then X min =[X5~X8] min ;

[0211] Judgment 5.3: When X can have both positive and negative values, △C = X max -X min X max and X min The value is determined by the region selected in the above judgment 5.1. If the selected region is [X1~X4], then X max =[X1~X4] max X min =[X1~X4] min If the selected region is [X5~X8], then X max =[X5~X8] max X min =[X5~X8] min .

[0212] Further, based on the calculated coaxiality error △C between the main spindle and the C-axis, a sixth-level judgment is performed:

[0213] Judgment 6.1: When the value of |△C| is less than the allowable value for accuracy, the coaxiality of the spindle and the C-axis can be considered to meet the requirements.

[0214] Judgment 6.2: When the value of |△C| is greater than or equal to the allowable accuracy value, it is necessary to re-check the coaxiality accuracy error between the spindle and the C-axis. Follow step S1 in this embodiment, input the detection program and execute it, set the machine tool feed rate to 100%, and do not arbitrarily adjust the feed rate during the detection process. The specific procedure is as follows:

[0215] (36) Execute G500 TRAORI; activate the machine tool coordinate system and five-axis linkage function;

[0216] (37) Execute G01 F500; set the speed;

[0217] (38) Execute A0 C0, G4 F3; move to the set angle θ9 and stop for 3 seconds, record the dial gauge reading X. 11 ;

[0218] (39) Execute A0 C90, G4 F3; move to the set angle θ 10 Stop for 3 seconds and record the dial gauge reading X. 12 ;

[0219] (40) Execute A0 C180, G4 F3; move to the set angle θ 11 Stop for 3 seconds and record the dial gauge reading X. 13 ;

[0220] (41) Execute A0 C270, G4 F3; move to the set angle θ 12 Stop for 3 seconds and record the dial gauge reading X. 14 .

[0221] Furthermore, the coaxiality deviation between the spindle and the C-axis in the X direction is calculated as λ3 = X. 11 -X 13 Then, the coaxiality deviation compensation value between the spindle and the C-axis in the X direction is λ4 = λ3 / 2; calculate the coaxiality deviation between the spindle and the C-axis in the Y direction λ5 = X 12 -X 14 Then, the coaxiality of the spindle and the C-axis in the Y-direction deviation compensation value λ6 = λ5 / 2; calculate the compensation values ​​λ4 and λ6 with their respective original system parameter compensation values, and then compensate the new values ​​back into their respective original system parameters; after the compensation is completed, the procedures (30) (31) (32) (33) (34) (35) in step S3 of this embodiment need 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 value.

[0222] After further compensation is completed, steps S1 to S3 in Example 2 above should be executed again to ensure that the X-axis error of RTCP accuracy meets the requirements.

[0223] Example 3

[0224] Based on Example 2, this example further explains the Y-axis error of RTCP accuracy detection. The operation steps are as follows:

[0225] Step S1: Execute the program: G01 F500 A0 C0 M2, bring the A / C axis to zero, adjust the dial indicator posture so that the indicator needle points towards the positive Y direction of the machine tool, as shown in Figure 1; use the handwheel to move the machine tool so that the ball at the top of the ball head probe contacts the dial indicator needle, move the X-axis in both positive and negative directions to find the highest point of the ball head in the X direction; move the Z-axis in both positive and negative directions to find the highest point of the ball head in the Z direction; move the Y-axis in both positive and negative directions so that the ball re-contacts the needle and the dial indicator presses down 0.2mm, rotate the dial indicator dial to make the pointer point to zero.

[0226] Step S2: Perform the detection according to step S2 of Embodiment 2 above, and record the eight set angles θ and the dial gauge readings Y. The motion trajectory is shown in Figure 5. The correspondence between each angle motion combination and the corresponding reading is as follows:

[0227] Y-axis error setting angle dial gauge readings: First angle θ1 A90 C0Y1; Second angle θ2 A90 C90Y2; Third angle θ3 A90 C180Y3; Fourth angle θ4 A90 C270Y4; Fifth angle θ5 A-90 C0Y5; Sixth angle θ6 A-90 C90Y6; Seventh angle θ7 A-90 C180Y7; Eighth angle θ8 A-90 C270Y8

[0228] Further, based on the values ​​of Y1 to Y8 detected in step S2 of embodiment 3, and performing a first-level judgment on the three possible Y value situations, the RTCP accuracy status ΔY is calculated:

[0229] Judgment 1.1: When all Y values ​​are positive, ΔY = Y max Y max =[Y1~Y8] max ;

[0230] Judgment 1.2: When all Y values ​​are negative, ΔY = |Y| min |, Y max =[Y1~Y8] max ;

[0231] Judgment 1.3: When Y has both positive and negative values, ΔY = Y max -Y min Y max =[Y1~Y8] max Y max =[Y1~Y8] max .

[0232] Further, based on the calculated RTCP accuracy △Y, a second-level judgment is performed:

[0233] Judgment 2.1: When the value of |△Y| is less than the allowable value for precision, the Y-axis error of RTCP precision can be considered to meet the requirements.

[0234] Judgment 2.2: When the value of |△Y| is greater than or equal to the accuracy allowable value, it can be considered that the X-axis error compensation of RTCP accuracy has affected the Z-axis and Y-axis errors of RTCP accuracy. Therefore, it is necessary to re-detect and compensate for the Z and X-axis errors of RTCP accuracy until the X, Y and Z-axis errors of RTCP accuracy all meet the requirements.

Claims

1. A method for RTCP accuracy detection and compensation in CNC machine tools, characterized in that, Includes the following steps: Step S1: Install the ball end gauge on the machine tool spindle and enter the length in the ball end gauge length field of the tool list; Step S2: Set up the dial indicator and adjust its attitude so that the pointer points towards 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. Rotate the dial indicator dial to make the pointer point to zero. By executing a fixed NC inspection program, detect the Z-axis error of the RTCP accuracy and evaluate the RTCP accuracy status. If it meets the requirements, proceed to the next accuracy test. If it does not meet the requirements, it is necessary to detect and compensate for the accuracy errors of each item until the Z-axis error of the RTCP accuracy meets the requirements. Step S3: Set up the dial indicator and adjust its attitude so that the pointer points towards 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. Rotate the dial indicator dial to make the pointer point to zero. By executing a fixed NC inspection program, detect the X-axis error of the RTCP accuracy and evaluate the RTCP accuracy status. If it meets the requirements, proceed to the next accuracy test. If it does not meet the requirements, it is necessary to detect and compensate for the accuracy errors of each item until the X-axis error of the RTCP accuracy meets the requirements. Step S4: Set up the dial indicator and adjust its attitude so that the pointer points towards 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. Rotate the dial indicator dial to make the pointer point to zero. By executing a fixed NC detection program, detect the Y-axis 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 for the X and Z-axis errors of the RTCP accuracy until the X, Y, and Z-axis errors of the RTCP accuracy all meet the requirements.

2. The method for RTCP accuracy detection and compensation of CNC machine tools as described in claim 1, characterized in that, In step S2, the Z-axis error of RTCP accuracy is detected by executing a fixed NC detection program, including: with the TRAORI command enabled, the machine tool moves sequentially to the eight composite angles θ formed by the combination of the swing axis A and the rotary axis C, and the dial gauge values ​​Z1 to Z8 are recorded at each composite angle. The angles of the A axis are selected as 90° and -90°, and the angles of the C axis are selected as 0°, 90°, 180°, and 270°.

3. The method for RTCP accuracy detection and compensation of CNC machine tools as described in claim 2, characterized in that, In step S2, a fixed NC detection program is executed to detect the Z-axis error of the RTCP accuracy, including: based on the values ​​of Z1 to Z8, performing a first-level judgment on the three possible Z-value situations, and calculating the RTCP accuracy ΔZ. Judgment 1.1: When Z1 to Z8 are all positive, ΔZ = Z max Z max =[Z1~Z8] max ; Judgment 1.2: When Z1 to Z8 are all negative, △Z = |Z min |, Z min =[Z1~Z8] min ; Judgment 1.3: When Z1 to Z8 can be either positive or negative, △Z = Z max -Z min Z max =[Z1~Z8] max Z min =[Z1~Z8] min .

4. The method for RTCP accuracy detection and compensation of CNC machine tools as described in claim 3, characterized in that, In step S2, evaluating the RTCP accuracy status includes performing a second-level judgment based on the calculated RTCP accuracy status △Z: Judgment 2.1: When the value of △Z is less than the precision allowable value, the Z-axis error of RTCP precision meets the requirements; Judgment 2.2: When the value of △Z is greater than or equal to the accuracy allowable value, the Z-axis error of RTCP accuracy does not meet the requirements. It is necessary to calculate and compensate for each component error that makes up the RTCP accuracy. Each component error includes the deviation between the spindle and the A-axis in the Y direction, the deviation from the spindle end face to the rotation center of the A-axis, and the rotation plane error of the C-axis.

5. The method for RTCP accuracy detection and compensation of CNC machine tools as described in claim 4, characterized in that, In judgment 2.2, the calculation and compensation of the individual errors that make up the RTCP accuracy include: Based on the dial gauge values ​​Z1 and Z5 measured when the combined angles are 90° A-axis / 0° C-axis and -90° A-axis / 0° C-axis respectively, a third-level judgment is made on the three possible Z value conditions, thereby calculating the deviation of the spindle from the A-axis in the Y direction and the deviation of the spindle end face from the rotation center of the A-axis: Judgment 3.1: When both Z1 and Z5 are positive or both are negative, the deviation λ1 between the principal axis and the A-axis in the Y direction is (Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, Z9, Z1, Z1, Z2, Z9, Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, Z9, Z1, Z9, Z1, Z2, Z9, Z1, max -Z min ) / 2, the deviation λ2 from the spindle end face to the rotation center of axis A is Z max -(Z max -Z min ) / 2, Z max =[Z1, Z5] max Z min =[Z1, Z5] min ; Judgment 3.2: When both Z1 and Z5 are negative, calculate the deviation λ1 between the principal axis and the A-axis in the Y direction = (Z min -Z max ) / 2, calculate the deviation λ2=Z from the spindle end face to the rotation center of axis A. min -(Z min -Z max ) / 2, Z max =[Z1, Z5] max Z min =[Z1, Z5] min ; Then, based on the calculated values ​​of λ1 and λ2, perform the fourth level of judgment: Judgment 4.1: When the values ​​of |λ1| and |λ2| are less than the precision allowable value, this item meets the requirement; Judgment 4.2: When the values ​​of |λ1| and |λ2| are greater than or equal to the permissible accuracy value, the deviations λ1 and λ2 are calculated with their respective original system parameter compensation values, and the calculated new values ​​are then compensated back into their respective original system parameters. After the compensation is completed, the dial gauge values ​​Z1 and Z5 need to be checked again, and the above third and fourth level judgments are executed in sequence until the values ​​of |λ1| and |λ2| are less than the permissible accuracy value.

6. The method for RTCP accuracy detection and compensation of CNC machine tools as described in claim 4, characterized in that, In judgment 2.2, the calculation and compensation of the individual errors that make up the RTCP accuracy include: Based on the dial gauge values ​​Z1, Z2, Z3, Z4 measured when the A-axis is 90° or Z5, Z6, Z7, Z8 measured when the A-axis is -90°, a fifth-level judgment is made on the three possible Z value situations, and the C-axis rotation plane error △C is calculated. Judgment 5.1: When all Z values ​​are positive, △C = Z max Z max =[Z1~Z4] max or Z max =[Z5~Z8] max ; Judgment 5.2: When all Z values ​​are negative, △C = |Z min |, Z min The value is determined by the region selected in the above judgment 5.

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

1. If the selected region is [Z1~Z4], then Z max =[Z1~Z4] max Z min =[Z1~Z4] min If the selected region is [Z5~Z8], then Z max =[Z5~Z8] max Z min =[Z5~Z8] min ; Then, based on the calculated C-axis rotational plane error △C, perform the sixth level of judgment: Judgment 6.1: When the value of △C is less than the allowable precision value, the C-axis rotation plane meets the requirements; Judgment 6.2: When the value of △C is greater than or equal to the allowable accuracy value, the accuracy error of the rotating plane needs to be re-checked. Perform manual dialing operation according to step S2, input the detection program and execute it. Set the machine tool feed rate to 100%. The feed rate cannot be adjusted arbitrarily during the detection process. The detection program is as follows: Execute G500 TRAORI; activate the machine tool coordinate system and five-axis linkage function; Execute G01 F500; Set movement speed; Execute A90 C0, M0; move to the set angle θ9, rotate the dial indicator dial to make the pointer point to zero, and record the dial indicator reading Z9; Run TRAFOOF to disable the five-axis linkage function; Execute A90 C90, M0; move to the set angle θ 10 Use the handwheel to move the X and Y axes, find the highest points of the sphere in the X and Y directions again, and record the dial gauge readings Z. 10 ; Execute A90 C180, M0; move to the set angle θ 11 Use the handwheel to move the X and Y axes, find the highest points of the sphere in the X and Y directions again, and record the dial gauge readings Z. 11 ; Execute A90 C270, M0; move to the set angle θ 12 Use the handwheel to move the X and Y axes, find the highest points of the sphere in the X and Y directions again, and record the dial gauge readings Z. 12 ; Then, take the dial gauge readings Z9 and Z2 obtained from the testing procedure. 10 Z 11 Z 12 The values ​​are compensated by reverse superposition, and the machine tool sag compensation function is used to compensate the C-axis rotation plane using the Z-axis. After compensation is completed, step S2 is executed again to ensure that the Z-axis error of RTCP accuracy meets the requirements.

7. The method for RTCP accuracy detection and compensation of CNC machine tools as described in claim 1, characterized in that, In step S3, the NC detection program of the RTCP accuracy X-axis error detection method refers to, with the TRAORI command enabled, the machine tool moves to the eight composite angles θ formed by the combination of the swing axis A and the rotary axis C, and records the dial gauge values ​​X1 to X8 at each composite angle; at the same time, the angles of the A axis are selected as 45° and -45°, and the angles of the C axis are selected as 0°, 90°, 180°, and 270°.

8. The method for RTCP accuracy detection and compensation of CNC machine tools as described in claim 7, characterized in that, In step S3, the X-axis error of RTCP accuracy is detected by executing a fixed NC detection program, including: Based on the values ​​of X1 to X8, a first-level judgment is made on the three possible X value scenarios, and the corresponding RTCP precision ΔX is calculated: Judgment 1.1: When X1 to X8 are all positive values, △X = X max X max =[X1~X8] max ; Judgment 1.2: When X1 to X8 are all negative, △X = |X min |, X min =[X1~X8] min ; Judgment 1.3: When X1 to X8 can be either positive or negative, △X = X max -X min X max =[X1~X8] max X min =[X1~X8] min ; Then, based on the calculated RTCP accuracy △X, a second-level judgment is performed: Judgment 2.1: When the value of △X is less than the precision allowable value, the X-axis error of RTCP precision meets the requirements; Judgment 2.2: When the value of △X is greater than or equal to the accuracy allowable value, the X-axis error of RTCP accuracy does not meet the requirements. It is necessary to calculate and compensate for each component error that makes up the RTCP accuracy. Each component error includes the A-axis rotation plane error and the coaxiality error between the principal axis and the C-axis.

9. The method for RTCP accuracy detection and compensation of CNC machine tools as described in claim 8, characterized in that, In judgment 2.2, the errors of each component constituting the RTCP accuracy are calculated and compensated, including: The third-level judgment is performed based on the values ​​of X1 and X5 measured when the composite angle is 45° / C0° and -45° / C0° respectively. The judgment method is consistent with the principle of the first-level judgment method, in order to calculate the A-axis rotation plane error △A. Then, based on the calculated rotational plane error △A along axis A, perform the fourth level of judgment: Judgment 4.1: Determine whether the value of △A is less than the allowable precision value. When the value of △A is less than the allowable precision value, the A-axis rotation plane meets the requirements. Judgment 4.2: When the value of △A is greater than or equal to the allowable accuracy value, the accuracy error of the rotating plane needs to be re-checked. Perform manual dialing operation according to step S3, then input and execute the detection program. Set the machine tool feed rate to 100%. The feed rate cannot be adjusted arbitrarily during the detection process. The specific procedure is as follows: Execute G500 TRAFOOF; activate the machine coordinate system and disable the five-axis linkage function; Execute G01 F500; Set movement speed; Execute A-90 C0, M0; move to the set angle θ9, use the handwheel to move the Y and Z axes, find the highest point of the sphere in the Y and Z directions again, and record the dial gauge reading X9; move Z to the safe point; Execute A-45 C0, M0; move to the set angle θ 10 Use the handwheel to move the Y and Z axes, find the highest points of the sphere in the Y and Z directions again, and record the dial gauge readings X. 10 Move Z to a safe point; Execute A45 C0, M0; move to the set angle θ 11 Use the handwheel to move the Y and Z axes, find the highest points of the sphere in the Y and Z directions again, and record the dial gauge readings X. 11 Move Z to a safe point; Execute A90 C0, M0; move to the set angle θ 12 Use the handwheel to move the X and Y axes, find the highest points of the sphere in the Y and Z directions, and record the dial indicator readings X. 12 Move Z to a safe point; Then X9 and X2 of the dial gauge readings. 10 X 11 X 12 The values ​​are compensated by reverse superposition, and the machine tool sag compensation function is used to compensate the A-axis rotation plane using the X-axis. After compensation is completed, the dial gauge 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.

10. The method for RTCP accuracy detection and compensation of CNC machine tools as described in claim 8, characterized in that, In judgment 2.2, the errors of each component constituting the RTCP accuracy are calculated and compensated, including: Based on 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°, perform the fifth-level judgment to calculate the coaxiality error △C between the principal axis and the C-axis: Judgment 5.1: When all values ​​of X are positive, △C = X max X max =[X1~X4] max or X max =[X5~X8] max ; Judgment 5.2: When all values ​​of X are negative, △C = |X| min |, Z min The value is determined by the region selected in the above judgment 5.

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

1. If the selected region is [X1~X4], then X max =[X1~X4] max X min =[X1~X4] min If the selected region is [X5~X8], then X max =[X5~X8] max X min =[X5~X8] min ; Based on the calculated coaxiality error △C between the main spindle and the C-axis, perform the sixth-level judgment: Judgment 6.1: When the value of △C is less than the allowable value, the coaxiality of 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 accuracy value, the coaxiality accuracy error between the spindle and the C-axis needs to be re-checked. Perform manual dialing operation according to step S3, then input and execute the detection program. Set the machine tool feed rate to 100%. The feed rate cannot be adjusted arbitrarily during the detection process. The specific procedure is as follows: Execute G500 TRAORI; activate the machine tool coordinate system and five-axis linkage function; Execute G01 F500; Set the speed; Execute A0 C0, G4 F3; move to the set angle θ9, and record the dial gauge reading X. 11 ; Execute A0 C90, G4 F3; move to the set angle θ 10 Record the dial gauge reading X 12 ; Execute A0 C180, G4 F3; move to the set angle θ 11 Record the dial gauge reading X 13 ; Execute A0 C270, G4 F3; move to the set angle θ 12 Record the dial gauge reading X 14 ; Calculate the coaxiality deviation of the spindle and C-axis in the X direction λ3=X 11 -X 13 Then, the coaxiality deviation compensation value between the spindle and the C-axis in the X direction is λ4 = λ3 / 2; calculate the coaxiality deviation between the spindle and the C-axis in the Y direction λ5 = X 12 -X 14 Then, the coaxiality of the spindle and the C-axis in the Y-direction deviation compensation value λ6 = λ5 / 2; calculate the compensation values ​​λ4 and λ6 with their respective original system parameter compensation values, and then compensate the new values ​​back into their respective original system parameters; 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 value; After compensation is completed, repeat step S3 above to ensure that the X-axis error of RTCP accuracy meets the requirements.

11. The method for RTCP accuracy detection and compensation of CNC machine tools as described in claim 1, characterized in that, The NC detection procedure in step S4 is the same as that in step S2, and a total of 8 composite angles θ1 to θ8 are detected, with corresponding dial gauge readings of Y1 to Y8; the RTCP accuracy ΔY is calculated based on the values ​​of Y1 to Y8. Judgment 1.1: When all Y values ​​are positive, ΔY = Y max Y max =[Y1~Y8] max ; Judgment 1.2: When all Y values ​​are negative, ΔY = |Y| min |, Y max =[Y1~Y8] max ; Judgment 1.3: When Y has both positive and negative values, ΔY = Y max -Y min Y max =[Y1~Y8] max Y max =[Y1~Y8] max ; Then, based on the calculated RTCP accuracy △Y, a second-level judgment is performed: Judgment 2.1: When the value of △Y is less than the precision allowable value, the Y-axis error of RTCP precision meets the requirements; Judgment 2.2: When the value of △Y is greater than or equal to the accuracy allowable value, it means that the X-axis error compensation of RTCP accuracy has affected the Z-axis and Y-axis errors of RTCP accuracy. Therefore, it is necessary to re-detect and compensate for the Z and X-axis errors of RTCP accuracy until the X, Y and Z-axis errors of RTCP accuracy all meet the requirements.

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