A numerical control machine tool positioning precision compensation method based on a position instruction frequency division algorithm

Abstract

The application discloses a numerical control machine tool positioning precision compensation method based on a position instruction frequency division algorithm. The method can comprise: establishing a starting origin and a detection end point of numerical control machine tool feed shaft positioning precision detection; measuring the length of the detection stroke and the positioning error of the feed shaft between the starting origin and the detection end point through a laser interferometer; according to the length of the detection stroke and the positioning error, iteratively optimizing a position instruction frequency division numerator and a position instruction frequency division denominator; and according to the iteratively optimized position instruction frequency division numerator and the position instruction frequency division denominator, compensating the positioning precision of the numerical control machine tool. The positioning precision of the numerical control machine tool feed shaft is measured through the laser interferometer, the numerical control machine tool positioning precision compensation method based on the position instruction frequency division algorithm is established, and the positioning precision of the numerical control machine tool can be improved.

Description

Technical Field

[0001] This invention relates to the field of CNC machine tools, and more specifically, to a method for compensating the positioning accuracy of CNC machine tools based on a position command frequency division algorithm. Background Technology

[0002] Before a CNC machine tool leaves the factory, manufacturers need to use laser detection to optimize parameters such as the numerator and denominator of the position command frequency division, thereby improving the positioning accuracy of the CNC machine tool.

[0003] Conventional methods require multiple complex calculations to change parameters such as the numerator and denominator of the position command frequency divider. After each calculation and parameter modification, the system needs to be powered on and off, and the laser needs to be re-detected. If the modified data is unreasonable, it needs to be recalculated and the detection steps repeated. Each calculation to change system parameters and re-collect data requires a long debugging time, resulting in low data modification efficiency.

[0004] Traditional calculation methods struggle to optimize laser detection data to its best state. While some machine tools can achieve acceptable laser detection data by optimizing parameters such as the numerator and denominator of the position command frequency division, existing calculation methods cannot meet debugging requirements, necessitating mechanical maintenance and rework.

[0005] Therefore, it is necessary to develop a CNC machine tool positioning accuracy compensation method based on a position command frequency division algorithm.

[0006] The information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] This invention proposes a CNC machine tool positioning accuracy compensation method based on a position command frequency division algorithm. It can measure the positioning accuracy of the feed axis of the CNC machine tool using a laser interferometer, and establish a CNC machine tool positioning accuracy compensation method based on a position command frequency division algorithm. It is practical and reliable, and can improve the positioning accuracy of CNC machine tools.

[0008] This disclosure provides a method for compensating the positioning accuracy of a CNC machine tool based on a position command frequency division algorithm, including:

[0009] Establish the starting origin and ending point for the positioning accuracy detection of CNC machine tool feed axes;

[0010] The length of the detection stroke and the positioning error of the feed axis are measured between the starting origin and the detection end point using a laser interferometer.

[0011] Based on the length of the detection journey and the positioning error, the numerator and denominator of the position command frequency division are iteratively optimized.

[0012] The positioning accuracy of the CNC machine tool is compensated based on the frequency division numerator and denominator of the position command after iterative optimization.

[0013] Preferably, the starting origin and the ending point for the positioning accuracy detection of the CNC machine tool feed axis are established according to the Cartesian coordinate system.

[0014] Preferably, the iterative optimization of the position command frequency divider numerator and denominator based on the length of the detection travel and the positioning error includes:

[0015] Determine the initial value b of the denominator of the frequency division of the position command;

[0016] Calculate the initial ratio of the numerator to the denominator based on the initial values ​​X1 and Y1 of the numerator and denominator set by the position command.

[0017] Based on the length of the detection stroke and the positioning error, calculate the ratio of the length of the pre-detected linear axis movement of the machine tool to the length of the actual linear axis movement of the machine tool;

[0018] The optimal ratio of the numerator to the denominator of the pre-compensated position command frequency division of the computer bed is used to calculate the corresponding numerator and denominator, which are the pre-compensated position command frequency division numerator and denominator.

[0019] Calculate the iteration threshold based on the optimal ratio;

[0020] Perform a loop calculation for the following steps:

[0021] The initial value of the denominator of the step position command frequency divider is b = b + 1;

[0022] Calculate the corresponding position command frequency division molecule c based on the ratio of the stepped b to the optimal value;

[0023] Take integer values ​​for c to obtain the integer frequency divider numerator;

[0024] Calculate the ratio of the integer frequency division numerator to the stepped b, and then round the ratio to obtain the processed ratio.

[0025] Determine if the processed ratio is equal to the iteration threshold. If not, step b and continue iterating. If yes, output the final position command frequency divider numerator and denominator.

[0026] Preferably, the ratio of the pre-detected length of linear axis movement of the machine tool to the actual length of linear axis movement of the machine tool is:

[0027] Z2 = X3 / ((Y2-X2) / 1000+X3)

[0028] Where Z2 is the ratio of the length of the pre-detected linear axis movement of the machine tool to the length of the actual linear axis movement of the machine tool, X3 is the length of the detection stroke, Y2 is the positioning error, and X2 is the initial value detected by the laser interferometer when the laser interferometer detects the zero point of the starting position of the linear axis of the machine tool.

[0029] Preferably, the optimal ratio of the numerator to the denominator of the pre-compensated position command frequency division is:

[0030] K = Z2 * Z1

[0031] Where K is the optimal ratio of the numerator to the denominator of the position command frequency division after machine tool pre-compensation, Z2 is the ratio of the pre-detected length of the linear axis movement of the machine tool to the actual length of the linear axis movement of the machine tool, and Z1 is the initial ratio of the numerator to the denominator.

[0032] Preferably, the iteration threshold is:

[0033] F = Round(K, Y3)

[0034] Where F is the iteration threshold, Round() is the rounding function, and Y3 is the rounding function starting from the Y3th decimal place.

[0035] Preferably, the frequency division molecule of the position command corresponding to step b is:

[0036] c = K * b

[0037] Where c is the frequency divider molecule of the position command corresponding to b after the step.

[0038] Preferably, the ratio after processing is:

[0039] g = Round(e, Y3)

[0040] Where g is the processed ratio, and e is the ratio of the integer frequency division molecule to the stepped b.

[0041] Preferably, the integer frequency divider numerator is the final position command frequency divider numerator, and the stepped b is the final position command frequency divider denominator.

[0042] Its beneficial effects are as follows:

[0043] 1. This invention can effectively solve the problem of multiple complex calculations in conventional methods, reduce the number of power cycles for data modification and the time required for re-acquiring data, and effectively improve the efficiency of laser detection.

[0044] 2. This invention can optimize the parameters of the numerator and denominator of the position command frequency division to optimize the laser detection data to the optimal state, thereby improving the accuracy and quality of laser detection compensation positioning.

[0045] The methods and apparatus of the present invention have other features and advantages that will be apparent from or will be set forth in detail in the accompanying drawings and following detailed description, which together serve to explain the particular principles of the invention. Attached Figure Description

[0046] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same parts.

[0047] Figure 1 A flowchart illustrating the steps of a CNC machine tool positioning accuracy compensation method based on a position command frequency division algorithm according to an embodiment of the present invention is shown.

[0048] Figure 2 A schematic diagram showing the detection results of the positioning accuracy of a CNC machine tool according to an embodiment of the present invention is illustrated.

[0049] Figure 3 A schematic diagram of the flow of an iterative position command frequency divider numerator and position command frequency divider denominator algorithm according to an embodiment of the present invention is shown.

[0050] Figure 4 A schematic diagram showing the detection results of the optimized positioning accuracy of a CNC machine tool according to an embodiment of the present invention is illustrated. Detailed Implementation

[0051] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0052] To facilitate understanding of the solutions and effects of the embodiments of the present invention, a specific application example is given below. Those skilled in the art should understand that this example is merely for the purpose of understanding the present invention, and any specific details therein are not intended to limit the present invention in any way.

[0053] Example 1

[0054] Figure 1 A flowchart illustrating the steps of a CNC machine tool positioning accuracy compensation method based on a position command frequency division algorithm according to an embodiment of the present invention is shown.

[0055] like Figure 1As shown, the CNC machine tool positioning accuracy compensation method based on position command frequency division algorithm includes: Step 101, establishing the starting origin and detection endpoint for CNC machine tool feed axis positioning accuracy detection; Step 102, measuring the length of the detection stroke and positioning error of the feed axis between the starting origin and detection endpoint using a laser interferometer; Step 103, iteratively optimizing the position command frequency division numerator and denominator based on the detection stroke length and positioning error; Step 104, compensating for the CNC machine tool positioning accuracy based on the iteratively optimized position command frequency division numerator and denominator.

[0056] In one example, the starting origin and ending point for the positioning accuracy detection of the CNC machine tool feed axis are established according to the Cartesian coordinate system.

[0057] In one example, based on the length of the detection travel and the positioning error, the position command frequency division numerator and denominator are iteratively optimized as follows:

[0058] Determine the initial value b of the denominator of the frequency division of the position command;

[0059] Calculate the initial ratio of the numerator to the denominator based on the initial values ​​X1 and Y1 of the numerator and denominator set by the position command.

[0060] Based on the length of the detection stroke and the positioning error, calculate the ratio of the length of the pre-detected linear axis movement to the actual length of the linear axis movement.

[0061] The optimal ratio of the numerator to the denominator of the pre-compensated position command frequency division of the computer bed is used to calculate the corresponding numerator and denominator based on the optimal ratio. These are the pre-compensated position command frequency division numerator and denominator.

[0062] Calculate the iteration threshold based on the optimal ratio;

[0063] Perform a loop calculation for the following steps:

[0064] The initial value of the denominator of the step position command frequency divider is b = b + 1;

[0065] Calculate the corresponding position command frequency divider c based on the ratio of b after stepping and the optimal value;

[0066] Take integer values ​​for c to obtain the integer frequency divider numerator;

[0067] Calculate the ratio of the integer frequency division numerator to the stepped b, and then round the ratio to obtain the processed ratio.

[0068] Determine if the processed ratio is equal to the iteration threshold. If not, step b and continue iterating. If yes, output the final position command frequency divider numerator and denominator.

[0069] In one example, the ratio of the pre-detected length of linear axis movement to the actual length of linear axis movement is:

[0070] Z2 = X3 / ((Y2-X2) / 1000+X3)

[0071] Where Z2 is the ratio of the length of the pre-detected linear axis movement of the machine tool to the length of the actual linear axis movement of the machine tool, X3 is the length of the detection stroke, Y2 is the positioning error, and X2 is the initial value detected by the laser interferometer when the laser interferometer detects the zero point of the starting position of the linear axis of the machine tool.

[0072] In one example, the optimal ratio of the numerator to the denominator of the pre-compensated position command frequency division is:

[0073] K = Z2 * Z1

[0074] Where K is the optimal ratio of the numerator to the denominator of the position command frequency division after machine tool pre-compensation, Z2 is the ratio of the pre-detected length of the linear axis movement of the machine tool to the actual length of the linear axis movement of the machine tool, and Z1 is the initial ratio of the numerator to the denominator.

[0075] In one example, the iteration threshold is:

[0076] F = Round(K, Y3)

[0077] Where F is the iteration threshold, Round() is the rounding function, and Y3 is the rounding function starting from the Y3th decimal place.

[0078] In one example, the frequency divider for the position command corresponding to step b is:

[0079] c = K * b

[0080] Where c is the frequency divider molecule of the position command corresponding to b after the step.

[0081] In one example, the processed ratio is:

[0082] g = Round(e, Y3)

[0083] Where g is the processed ratio, and e is the ratio of the integer frequency division molecule to the stepped b.

[0084] In one example, the integer frequency divider numerator is the final position command frequency divider numerator, and the stepped b is the final position command frequency divider denominator.

[0085] Specifically, the starting origin and ending point for the positioning accuracy detection of the CNC machine tool feed axis are established according to the Cartesian coordinate system.

[0086] Figure 2A schematic diagram showing the detection results of the positioning accuracy of a CNC machine tool according to an embodiment of the present invention is illustrated.

[0087] The length of the feed axis's detection stroke and positioning error are measured between the starting origin and the detection endpoint using a laser interferometer. The positioning error is as follows: Figure 2 As shown.

[0088] Figure 3 A schematic diagram of the flow of an iterative position command frequency divider numerator and position command frequency divider denominator algorithm according to an embodiment of the present invention is shown.

[0089] like Figure 3 As shown, the input is the original position command frequency divider numerator X1, the original position command frequency divider denominator Y1, the positioning error of the starting origin X2, the positioning error of the detection endpoint Y2, the detection travel length X3, and the number of decimal places retained after the intermediate value Y3 is calculated during the iteration process. Based on the detection travel length and the positioning error, the position command frequency divider numerator and the position command frequency divider denominator are iteratively optimized.

[0090] The initial value of the denominator of the frequency division of the position command is determined to be b = 1;

[0091] Based on the initial values ​​X1 and Y1 of the numerator and denominator of the position command frequency division, the initial ratio Z1 = X1 / Y1 is calculated. The difference between b and Y1 is as follows: b is an assumed value for calculation, assuming the denominator value of the position command frequency division, assuming an initial value of 1, b = b + 1, so b is an iteratively increasing value, b = 1, 2, 3, etc., and the b value is selected according to the conditions; Y1 is the initial value of the parameter set in the machine tool operating system. This parameter is the denominator value that is retained in the system after the system is turned on. After precise calculation, the initial value of Y1 in this system is changed to achieve better parameter compensation. In other words, b is artificially assumed to be an initial value of 1 and increased for calculation, while Y1 is the initial value that already exists in the system after startup, and this number is a system default random number.

[0092] Based on the length of the detection stroke and the positioning error, calculate the ratio of the pre-detected length of the machine tool linear axis movement to the actual length of the machine tool linear axis movement: Z2 = X3 / ((Y2-X2) / 1000+X3), where X3 is the length detected by the laser interferometer on the machine tool linear axis, Y2 is the machine tool positioning accuracy error value detected by the laser interferometer when the machine tool linear axis moves to the end position, and X2 is the initial value detected by the laser interferometer when the machine tool linear axis starts at zero (generally 0); the result of (Y2-X2) / 1000 is the machine tool positioning accuracy value detected by the laser interferometer, converted from millimeters to micrometers by converting the unit to micrometers using 1000; the result of Z2 is the ratio of the pre-detected length of the machine tool linear axis movement to the actual length of the machine tool linear axis movement.

[0093] The optimal ratio of the numerator to the denominator of the pre-compensated position command frequency division is K = Z2 * Z1. The corresponding numerator and denominator are calculated based on the optimal ratio, which are the pre-compensated position command frequency division numerator and denominator. The optimized numerator-denominator ratio is calculated based on the machine tool positioning accuracy error. The new ratio can eliminate some of the positioning accuracy error caused by the machine tool's mechanical error, thereby performing parameter compensation and making the linear axis movement distance of the machine tool more precise and accurate.

[0094] The iteration threshold F = Round(K, Y3) is calculated based on the optimal ratio. The precision of the K value is determined by the custom Y3 value. The larger the custom Y3 value, the higher the precision of the F value.

[0095] Perform a loop calculation for the following steps:

[0096] The initial value of the denominator of the step position command frequency divider is b = b + 1;

[0097] Calculate the corresponding position command frequency divider c = K * b based on the ratio of b after stepping and the optimal value;

[0098] Round c to an integer to obtain the integer frequency divider numerator d = Round(c, 0);

[0099] Calculate the ratio e = d / b between the integer frequency division numerator and the stepped b, and then round the ratio to obtain the processed ratio g = Round(e,Y3).

[0100] Determine if the processed ratio is equal to the iteration threshold. If not, step b and continue iterating. If yes, output the integer numerator as the final position command numerator, and the step b as the final position command denominator.

[0101] The algorithm is as follows:

[0102] b=1

[0103] Z1 = X1 / Y1

[0104] Z2 = X3 / ((Y2-X2) / 1000+X3)

[0105] K = Z2 * Z1

[0106] F = Round(K, Y3)

[0107] Do

[0108] b = b + 1

[0109] c = K * b

[0110] d = Round(c, 0)

[0111] e = d / b

[0112] g = Round(e, Y3)

[0113] Loop until g = F

[0114] Figure 4 A schematic diagram showing the detection results of the optimized positioning accuracy of a CNC machine tool according to an embodiment of the present invention is illustrated.

[0115] The positioning accuracy of the CNC machine tool is compensated based on the frequency division numerator and denominator of the position command after iterative optimization. The detection results are as follows: Figure 4 As shown.

[0116] Those skilled in the art should understand that the above description of the embodiments of the present invention is only intended to illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any of the examples given.

[0117] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for compensating the positioning accuracy of a CNC machine tool based on a position command frequency division algorithm, characterized in that, include: Establish the starting origin and ending point for the positioning accuracy detection of CNC machine tool feed axes; The length of the detection stroke and the positioning error of the feed axis are measured between the starting origin and the detection end point using a laser interferometer. Based on the length of the detection journey and the positioning error, the numerator and denominator of the position command frequency division are iteratively optimized. The positioning accuracy of the CNC machine tool is compensated based on the frequency division numerator and denominator of the position command after iterative optimization. Specifically, based on the length of the detection journey and the positioning error, the iterative optimization of the position command frequency division numerator and denominator includes: Determine the initial value b of the denominator of the frequency division of the position command; Calculate the initial ratio of the numerator to the denominator based on the initial values ​​X1 and Y1 of the numerator and denominator set by the position command. Based on the length of the detection stroke and the positioning error, calculate the ratio of the length of the pre-detected linear axis movement of the machine tool to the length of the actual linear axis movement of the machine tool; The optimal ratio of the numerator to the denominator of the pre-compensated position command frequency division of the computer bed is used to calculate the corresponding numerator and denominator, which are the pre-compensated position command frequency division numerator and denominator. Calculate the iteration threshold based on the optimal ratio; Perform a loop calculation for the following steps: The initial value of the denominator for the step position command frequency divider is b = b + 1; Calculate the corresponding position command frequency division molecule c based on the ratio of the stepped b to the optimal value; Take an integer value for c to obtain the integer frequency divider numerator; Calculate the ratio of the integer frequency division numerator to the stepped b, and then round the ratio to obtain the processed ratio. Determine if the processed ratio is equal to the iteration threshold. If not, step b and continue iterating. If yes, output the final position command frequency divider numerator and denominator.

2. The CNC machine tool positioning accuracy compensation method based on position command frequency division algorithm according to claim 1, wherein, Establish the starting origin and ending point for CNC machine tool feed axis positioning accuracy detection using the Cartesian coordinate system.

3. The CNC machine tool positioning accuracy compensation method based on position command frequency division algorithm according to claim 1, wherein, The ratio of the pre-detected linear axis movement length to the actual linear axis movement length is: Z2 = X3 / ((Y2 - X2) / 1000 + X3) Where Z2 is the ratio of the length of the pre-detected linear axis movement of the machine tool to the length of the actual linear axis movement of the machine tool, X3 is the length of the detection stroke, Y2 is the positioning error, and X2 is the initial value detected by the laser interferometer when the laser interferometer detects the zero point of the starting position of the linear axis of the machine tool.

4. The CNC machine tool positioning accuracy compensation method based on position command frequency division algorithm according to claim 1, wherein, The optimal ratio of the numerator to the denominator of the pre-compensated position command frequency division is: K = Z2 Z1 Where K is the optimal ratio of the numerator to the denominator of the position command frequency division after machine tool pre-compensation, Z2 is the ratio of the pre-detected length of the linear axis movement of the machine tool to the actual length of the linear axis movement of the machine tool, and Z1 is the initial ratio of the numerator to the denominator.

5. The CNC machine tool positioning accuracy compensation method based on position command frequency division algorithm according to claim 1, wherein, The iteration threshold is: F = Round(K, Y3) Where F is the iteration threshold, Round() is the rounding function, and Y3 is the rounding function starting from the Y3th decimal place.

6. The CNC machine tool positioning accuracy compensation method based on position command frequency division algorithm according to claim 1, wherein, The frequency divider for the position command corresponding to step b is: c = K b Where c is the frequency divider molecule of the position command corresponding to b after the step.

7. The CNC machine tool positioning accuracy compensation method based on position command frequency division algorithm according to claim 1, wherein, The ratio after processing is: g = Round(e, Y3) Where g is the processed ratio, and e is the ratio of the integer frequency division molecule to the stepped b.

8. The CNC machine tool positioning accuracy compensation method based on position command frequency division algorithm according to claim 1, wherein, The integer frequency divider numerator is the final position command frequency divider numerator, and the stepped b is the final position command frequency divider denominator.

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