Laser galvanometer distortion correction method based on bicubic spline interpolation and laser galvanometer system

Abstract

The application relates to a laser galvanometer distortion correction method based on bicubic spline interpolation, which comprises the following steps: S1, acquiring a plurality of theoretical grid points and corresponding actual measurement points; S2, constructing a bicubic spline interpolation function; S3, solving the bicubic spline interpolation function to calculate the driving digital signal DA value corresponding to the target coordinate, and obtaining a global data table LUT; S4, inputting the global data table LUT into the bicubic spline interpolation function to obtain a correction output point, and judging whether the accuracy requirement is met by calculating the error value between the correction output point and the theoretical grid point; and S5, local area compensation correction, obtaining correction global data, and replacing the global data table LUT with the correction global data. The application can guarantee the smoothness and accuracy of the whole plane, can separately remeasure and fit the local area with large errors, the formed local data can be seamlessly spliced with the global data table LUT, and the grid size at the non-measurement point can be consistent with the theoretical value.

Description

Technical Field

[0001] This invention relates to the field of laser processing equipment technology, and in particular to a laser galvanometer distortion correction method based on bicubic spline interpolation and a laser galvanometer. Background Technology

[0002] A laser galvanometer is a commonly used high-speed two-dimensional scanning device, widely applied in laser marking, laser welding, and 3D imaging. The galvanometer controls the rotation angle of the reflector by inputting a digital value (DA value), thereby changing the position of the laser beam on the working plane. However, due to factors such as manufacturing precision of the galvanometer lenses, assembly errors, nonlinearity of the drive circuit, and optical distortion, there is a deviation between the theoretical input and the actual output.

[0003] To address the above problems, the traditional method is to use polynomial fitting. However, this method can only make approximate corrections within the overall range, and it is powerless to deal with the problem of inaccurate local dimensions between non-measured points. As a result, although the overall position is accurate, the grid size is still uneven.

[0004] Chinese patent CN110987944B describes a method for detecting surface defects in laser brazing welds based on envelope recognition. After obtaining the weld surface contour data, a weighted cubic spline curve is used to fit the actual contour curve in real time to obtain a standard contour. The standard contour is then shifted upwards and downwards by fluctuation distances to obtain weld seam acceptable intervals. The actual contour curve is compared with the acceptable intervals: if the actual contour curve is entirely within the acceptable intervals, the weld is defect-free; if the actual contour curve is higher than the upper contour line or lower than the lower contour line, and the area of ​​the excess portion is greater than or equal to a threshold, the weld contour is unacceptable; if the number of consecutive unacceptable weld contours reaches the critical size value for weld defects, the weld is determined to have defects. Based on this, defect classification and corresponding feature values ​​are calculated. However, this method uses a weighted cubic spline curve, which is only suitable for one-dimensional data processing. Furthermore, the weighted cubic spline curve relies on experience in setting weights, and improper weight settings can lead to results deviating from the true trend. Summary of the Invention

[0005] Based on this, it is necessary to address the problem that existing polynomial fitting methods can only make approximate corrections within the overall range, but are powerless to address the problem of inaccurate local dimensions between non-measured points, resulting in an overall position that is accurate but the grid size is still uneven. Furthermore, weighted cubic spline curves are not suitable for two-dimensional data, and relying on experience in weight setting can easily lead to results that deviate from the true trend. Therefore, a laser galvanometer distortion correction method and laser galvanometer system based on bicubic spline interpolation should be provided.

[0006] A laser galvanometer distortion correction method based on bicubic spline interpolation includes the following steps: S1. Within the effective marking area of ​​the galvanometer, obtain several theoretical grid points and corresponding actual measurement points; The actual measurement points are obtained by using measuring instruments (such as visual positioning, manual measurement, and scanner measurement).

[0007] S2. Construct a bicubic spline interpolation function based on the theoretical grid points and the actual measurement points; S3. Calculate the driving digital signal DA value corresponding to the target coordinates by reverse solving the bicubic spline interpolation function according to the iterative solution or numerical approximation method, and obtain the global data table LUT. S4. Input the global data table LUT into the bicubic spline interpolation function to obtain the corrected output points. Determine whether the accuracy requirements are met by calculating the error value between the corrected output points and the theoretical points. If yes, output the global data table LUT; otherwise, proceed to S5. The main criterion for determining whether the accuracy requirement is met is to set an error threshold. When the error value is less than the error threshold, the accuracy requirement is met; when the error value is not less than the error threshold, the accuracy requirement is not met. S5. Local area compensation and correction are performed to obtain global correction data. The global correction data replaces the global data table LUT and proceeds to S4.

[0008] As a preferred embodiment, the method for constructing a bicubic spline interpolation function based on the theoretical grid points and the actual measurement points described in S2 includes the following steps: S21. Divide the galvanometer calibration plane into a uniform rectangular grid, then divide the rectangular grid into rectangular elements, and in each rectangular element... Internally set bicubic spline interpolation basis functions in These are interpolation coefficients, a total of 16, with p ranging from 0 to 3 and q ranging from 0 to 3; S22. Calculate the interpolation coefficients in the bicubic spline interpolation basis function using the constraint equations of the bicubic spline interpolation and the actual measured point coordinates. Constraint equations: , in, Node values, i.e., the coordinates of the actual measured points corresponding to the theoretical grid points within the rectangular element. First-order partial derivative in the x-direction First-order partial derivative in the y-direction, Let A be the mixed second-order partial derivative, A be the polynomial interpolation basis function matrix, a be the interpolation coefficients, and b be the boundary values; S23. Construct the bicubic spline interpolation function in the X direction and the bicubic spline interpolation function in the Y direction based on the interpolation coefficients; X-axis bicubic spline interpolation function: in, : Input X-axis and Y-axis drive signals; : X-channel interpolation coefficients of the k-th unit, a total of 16, p,q=0,1,2,3; Theoretical grid point coordinates; Y-axis bicubic spline interpolation function: in, : Input X-axis and Y-axis drive signals; : Y-channel interpolation coefficients of the k-th unit, a total of 16, p,q=0,1,2,3; Theoretical grid point coordinates.

[0009] As a preferred embodiment, the method for calculating the first-order partial derivative in the x-direction is to construct a natural cubic spline along the X-direction using the coordinates of the actual measured points corresponding to the theoretical grid points within the rectangular unit as node values, and then calculate it using the Thomas algorithm.

[0010] The first-order partial derivative in the x-direction is the rate of change of the y-direction driving signal with respect to the y-coordinate of the actual measurement point when y is fixed.

[0011] Assume that y has a fixed value By establishing the equation through the "continuity of the second derivative", let (The second derivative at node xi), then the system of equations takes the form: Thomas' algorithm is an efficient solution method specifically designed for tridiagonal systems of equations. It calculates the second derivative Mi at all x nodes in a row through two steps: forward elimination and backward substitution.

[0012] According to the derivative relationship of a cubic polynomial, the first derivative at node xi can be calculated from the function values ​​and second derivatives of adjacent nodes: As a preferred embodiment, the method for calculating the first-order partial derivative in the y-direction is to construct a natural cubic spline along the y-direction using the coordinates of the actual measured points corresponding to the theoretical grid points within the rectangular unit as node values, and then calculate it using the Thomas algorithm.

[0013] The first-order partial derivative in the y-direction is the rate of change of the y-direction driving signal with respect to the y-coordinate of the actual measurement point when x is fixed.

[0014] Assume x has a fixed value By establishing the equation through the "continuity of the second derivative", let (node (the second derivative at point), then the system of equations takes the form: Thomas' algorithm is an efficient solution method specifically designed for tridiagonal systems of equations. It solves all equations in a given row through two steps: forward elimination and backward substitution. Second derivative at the node .

[0015] According to the derivative relation of a cubic polynomial, the nodes The first derivative at a given point can be calculated from the function values ​​and second derivatives of adjacent nodes: As a preferred embodiment, the method for calculating the hybrid second-order partial derivative is to derive it by cross-deriving the second-order derivative of the natural cubic spline based on the first-order derivative values ​​of each node in the x-direction and the first-order derivative values ​​of each node in the y-direction.

[0016] For example, for fixed Extract the first-order partial derivatives in the X direction for all Y nodes in this column to form "Y-driven - first-order partial derivative" data pairs: {( , ),( , ),...,( , )}, where the first-order partial derivative in the x-direction is known; Construct a natural cubic spline along the Y direction based on the known data above, and fit the above data into a natural cubic spline about Y. ,satisfy: Natural boundary: The second derivative of the first and last nodes is 0; The first-order partial derivative of spline S(y) with respect to the Y direction is the same as the partial derivative of the first-order partial derivative of the X direction with respect to Y, which is the mixed second-order partial derivative. The specific derivation process is the same as that of the first-order partial derivative of the Y direction above, and will not be repeated here. It should be noted that the mixed second-order partial derivative can also be obtained by extracting the x-direction sequence of the first-order partial derivative of the y direction, constructing a natural cubic spline along the x direction, and calculating the partial derivative of the first-order partial derivative of the y direction with respect to x.

[0017] As a preferred embodiment, the method described in S3 for calculating the driving digital signal DA value corresponding to the target coordinates by inversely solving the bicubic spline interpolation function using iterative solutions or numerical approximation includes the following steps: S31, Set the target coordinates In the X-direction and Y-direction bicubic spline interpolation functions, and make... The driving digital signal corresponding to the target coordinates is calculated through iterative solution or numerical approximation. ; S32. Calculate the driving digital signal obtained in S31 according to the coordinate transformation DA formula. Corresponding DA value ; The coordinate transformation DA formula is as follows: ; ; Where Q is the correction area.

[0018] Even after full-area calibration, certain local areas may still exhibit dimensional inaccuracies or deviations due to measurement errors, local optical distortions, or mechanical instabilities. Using only a single global calibration may result in insufficient accuracy for that area. Therefore, secondary measurements and local interpolation fitting are necessary for this local area to achieve higher accuracy than the global calibration.

[0019] As a preferred option, S5, the local area compensation and correction method, includes the following steps: S51. Based on the error value results, select a local area to remeasure at a higher resolution; by calculating the error value, it is possible to quickly identify which areas have large data differences, thereby quickly pinpointing the local area that needs to be remeasured.

[0020] S52. Construct a local bicubic spline interpolation function based on local area measurement data; This step is consistent with the steps S1-S3 described above, and will not be repeated here.

[0021] S53. Use the local interpolation results to form local data, and replace the data in the corresponding area of ​​the global data table LUT with the local data; Assuming local region ,but in, Local data, and for .

[0022] Directly replacing the corresponding area of ​​data in the global data table LUT with local data can cause abrupt changes or discontinuities at the boundaries, thus affecting the smoothness and transition accuracy of the galvanometer motion. Therefore, a weighted fusion process is needed to perform on the buffer between the local data and the global data table LUT to maintain the smoothness and transition accuracy of the galvanometer motion.

[0023] S54. By weighted fusion processing of the buffer between local data and global data table LUT, corrected global data is obtained.

[0024] As a preferred embodiment, the buffer between the local data and the global data table LUT described in S54 is processed by a weighted fusion method, including the following steps: S541. Set the buffer width and divide the global data table LUT into the core area, buffer area and peripheral area; S542, Set the weights for each region ; , in, S543. Divide the buffer into a left buffer, a lower buffer, a right buffer, and an upper buffer. Calculate the weight of each buffer. Then, multiply the weight of the left buffer by the weight of the lower buffer, and the weight of the right buffer by the weight of the upper buffer, respectively, to obtain the combined weight. Left buffer weights: ; Lower buffer weights: ; Right buffer weights: ; Upper buffer weights: ; Among them, the boundary of the core area W is the buffer width; S544, Based on comprehensive weighting Calculate the correction data within the buffer. ; Fusion formula: in, .

[0025] A laser galvanometer system, comprising: The calibration data acquisition module is used to obtain theoretical grid points and actual measurement points; The interpolation calculation module is used to construct a bicubic spline interpolation function based on the theoretical grid points and the actual measurement points, and to construct a local bicubic spline interpolation function based on the measurement data of the local area. The LUT generation module is used to generate a global data table LUT by back-solving the bicubic spline interpolation function according to iterative solution or numerical approximation, to generate local data by back-solving the local bicubic spline interpolation function according to iterative solution or numerical approximation, and to replace the global data table LUT with the corrected global data. The judgment module is used to input the global data table LUT into the bicubic spline interpolation function to obtain the corrected output points, and to determine whether the accuracy requirements are met by calculating the error value between the corrected output points and the theoretical grid points, and to select local areas based on the error results. The compensation and correction module is used to replace the data in the corresponding area of ​​the global data table LUT with local data and generate corrected global data by weighted fusion processing of the buffer between the local data and the global data table LUT; and The marking control module is used to correct the galvanometer control signal according to the global data table LUT during the marking process, thereby outputting the corrected marking path.

[0026] The beneficial effects of this invention are as follows: by using bicubic spline interpolation, a small number of measurement points are expanded into a high-density global data table (LUT), ensuring the smoothness and accuracy of the entire area; when there are still dimensional errors in local areas (such as corner areas or certain key locations), the area can be remeasured and fitted separately to generate local data, which is then seamlessly spliced ​​with the global data table (LUT), maintaining the smoothness and transition accuracy of the galvanometer movement; local correction only applies to local areas, while other areas retain the original global correction results, avoiding overall destruction; it supports multiple iterative optimizations to gradually improve marking accuracy, enabling the grid size at non-measurement points to tend to be consistent with the theoretical value. Attached Figure Description

[0027] Figure 1 This is a flowchart of the laser galvanometer distortion correction method based on bicubic spline interpolation of the present invention; Figure 2 This is a flowchart of the method for constructing a bicubic spline interpolation function based on the theoretical grid points and actual measurement points according to the present invention; Figure 3 This is a flowchart of the method for calculating the driving digital signal DA value corresponding to the target coordinates based on the reverse solution of the bicubic spline interpolation function using a numerical iteration method according to the present invention. Figure 4 This is a flowchart of the local area compensation and correction method of the present invention; Figure 5 This is a flowchart illustrating the method of weighted fusion processing between the buffer of local data and global data table LUT in this invention. Detailed Implementation

[0028] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0029] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0030] Please see Figure 1 A laser galvanometer distortion correction method based on bicubic spline interpolation includes the following steps: S1. Within the effective marking area of ​​the galvanometer, obtain several theoretical grid points and corresponding actual measurement points; The actual measurement points are obtained by using measuring instruments (such as visual positioning, manual measurement, and scanner measurement).

[0031] S2. Construct a bicubic spline interpolation function based on the theoretical grid points and the actual measurement points; S3. Calculate the driving digital signal DA value corresponding to the target coordinates by reverse solving the bicubic spline interpolation function according to the iterative solution or numerical approximation method, and obtain the global data table LUT. S4. Input the global data table LUT into the bicubic spline interpolation function to obtain the corrected output points. Determine whether the accuracy requirements are met by calculating the error value between the corrected output points and the theoretical points. If yes, output the global data table LUT; otherwise, proceed to S5. The main criterion for determining whether the accuracy requirement is met is to set an error threshold. When the error value is less than the error threshold, the accuracy requirement is met; when the error value is not less than the error threshold, the accuracy requirement is not met. S5. Local area compensation and correction are performed to obtain global correction data. The global correction data replaces the global data table LUT and proceeds to S4.

[0032] Please see Figure 2 The method for constructing a bicubic spline interpolation function based on the theoretical grid points and actual measurement points, as described in S2, includes the following steps: S21. Divide the galvanometer calibration plane into a uniform rectangular grid, then divide the rectangular grid into rectangular elements, and in each rectangular element... Internally set bicubic spline interpolation basis functions in These are interpolation coefficients, a total of 16, with p ranging from 0 to 3 and q ranging from 0 to 3; S22. Calculate the interpolation coefficients in the bicubic spline interpolation basis function using the constraint equations of the bicubic spline interpolation and the actual measured point coordinates. Constraint equations: b= in, Node values, i.e., the coordinates of the actual measured points corresponding to the theoretical grid points within the rectangular element. First-order partial derivative in the x-direction First-order partial derivative in the y-direction, A is the polynomial interpolation basis function matrix, a is the interpolation coefficient, and b is the boundary value; S23. Construct the bicubic spline interpolation function in the X direction and the bicubic spline interpolation function in the Y direction based on the interpolation coefficients; X-axis bicubic spline interpolation function: in, : Input X-axis and Y-axis drive signals; : X-channel interpolation coefficients of the k-th unit, a total of 16, p,q=0,1,2,3; Theoretical grid point coordinates; Y-axis bicubic spline interpolation function: in, : Input X-axis and Y-axis drive signals; : Y-channel interpolation coefficients of the k-th unit, a total of 16, p,q=0,1,2,3; Theoretical grid point coordinates.

[0033] As a preferred embodiment, the method for calculating the first-order partial derivative in the x-direction is to construct a natural cubic spline along the X-direction using the coordinates of the actual measured points corresponding to the theoretical grid points within the rectangular unit as node values, and then calculate it using the Thomas algorithm.

[0034] The first-order partial derivative in the x-direction is the rate of change of the y-direction driving signal with respect to the y-coordinate of the actual measurement point when y is fixed.

[0035] Assume that y has a fixed value By establishing the equation through the "continuity of the second derivative", let (The second derivative at node xi), then the system of equations takes the form: Thomas' algorithm is an efficient solution method specifically designed for tridiagonal systems of equations. It calculates the second derivative Mi at all x nodes in a row through two steps: forward elimination and backward substitution.

[0036] According to the derivative relationship of a cubic polynomial, the first derivative at node xi can be calculated from the function values ​​and second derivatives of adjacent nodes: As a preferred embodiment, the method for calculating the first-order partial derivative in the y-direction is to construct a natural cubic spline along the y-direction using the coordinates of the actual measured points corresponding to the theoretical grid points within the rectangular unit as node values, and then calculate it using the Thomas algorithm.

[0037] The first-order partial derivative in the y-direction is the rate of change of the y-direction driving signal with respect to the y-coordinate of the actual measurement point when x is fixed.

[0038] Assume x has a fixed value By establishing the equation through the "continuity of the second derivative", let (node (the second derivative at point), then the system of equations takes the form: Thomas' algorithm is an efficient solution method specifically designed for tridiagonal systems of equations. It solves all equations in a given row through two steps: forward elimination and backward substitution. Second derivative at the node .

[0039] According to the derivative relation of a cubic polynomial, the nodes The first derivative at a given point can be calculated from the function values ​​and second derivatives of adjacent nodes: As a preferred embodiment, the method for calculating the hybrid second-order partial derivative is to derive it by cross-deriving the second derivative of the natural cubic spline based on the first-order derivative values ​​of each node in the x-direction and the first-order derivative values ​​of each node in the y-direction.

[0040] For example, for fixed Extract the first-order partial derivatives in the X direction for all Y nodes in this column to form "Y-driven - first-order partial derivative" data pairs: {( , ),( , ),...,( , )}, where the first-order partial derivative in the x-direction is known; Construct a natural cubic spline along the Y direction based on the known data above, and fit the above data into a natural cubic spline about Y. ,satisfy: Natural boundary: The second derivative of the first and last nodes is 0; The first-order partial derivative of spline S(y) with respect to the Y direction is the same as the partial derivative of the first-order partial derivative of the X direction with respect to Y, which is the mixed second-order partial derivative. The specific derivation process is the same as that of the first-order partial derivative of the Y direction above, and will not be repeated here. It should be noted that the mixed second-order partial derivative can also be obtained by extracting the x-direction sequence of the first-order partial derivative of the y direction, constructing a natural cubic spline along the x direction, and calculating the partial derivative of the first-order partial derivative of the y direction with respect to x.

[0041] Please see Figure 3 The method described in S3 for calculating the driving digital signal DA value corresponding to the target coordinates by inversely solving the bicubic spline interpolation function using iterative solutions or numerical approximation includes the following steps: S31, Set the target coordinates In the X-direction and Y-direction bicubic spline interpolation functions, and make... The driving digital signal corresponding to the target coordinates is calculated through iterative solution or numerical approximation. ; S32. Calculate the driving digital signal obtained in S31 according to the coordinate transformation DA formula. Corresponding DA value ; The coordinate transformation DA formula is as follows: ; ; Where Q is the correction area.

[0042] Even after full-area calibration, certain local areas may still exhibit dimensional inaccuracies or deviations due to measurement errors, local optical distortions, or mechanical instabilities. Using only a single global calibration may result in insufficient accuracy for that area. Therefore, secondary measurements and local interpolation fitting are necessary for this local area to achieve higher accuracy than the global calibration.

[0043] Please see Figure 4 S5. The method for local area compensation and correction includes the following steps: S51. Based on the error value results, select a local area to remeasure at a higher resolution; by calculating the error value, it is possible to quickly identify which areas have large data differences, thereby quickly pinpointing the local area that needs to be remeasured.

[0044] S52. Construct a local bicubic spline interpolation function based on local area measurement data; This step is consistent with the steps S1-S3 described above, and will not be repeated here.

[0045] S53. Use the local interpolation results to form local data, and replace the data in the corresponding area of ​​the global data table LUT with the local data; Assuming local region ,but in, Local data, and for .

[0046] Directly replacing the corresponding area of ​​data in the global data table LUT with local data can cause abrupt changes or discontinuities at the boundaries, thus affecting the smoothness and transition accuracy of the galvanometer motion. Therefore, a weighted fusion process is needed to perform on the buffer between the local data and the global data table LUT to maintain the smoothness and transition accuracy of the galvanometer motion.

[0047] S54. By weighted fusion processing of the buffer between local data and global data table LUT, corrected global data is obtained.

[0048] Please see Figure 5 The method for weighted fusion processing of the buffer between local data and global data table LUT as described in S54 includes the following steps: S541. Set the buffer width and divide the global data table LUT into the core area, buffer area and peripheral area; S542, Set the weights for each region ; , in, S543. Divide the buffer into a left buffer, a lower buffer, a right buffer, and an upper buffer. Calculate the weight of each buffer. Then, multiply the weight of the left buffer by the weight of the lower buffer, and the weight of the right buffer by the weight of the upper buffer, respectively, to obtain the combined weight. Left buffer weights: ; Lower buffer weights: ; Right buffer weights: ; Upper buffer weights: ; Among them, the boundary of the core area W is the buffer width; S544, Based on comprehensive weighting Calculate the correction data within the buffer. ; Fusion formula: in, This is the original data for the global data table LUT.

[0049] A laser galvanometer system, comprising: The calibration data acquisition module is used to obtain theoretical grid points and actual measurement points; The interpolation calculation module is used to construct a bicubic spline interpolation function based on the theoretical grid points and the actual measurement points, and to construct a local bicubic spline interpolation function based on the measurement data of the local area. The LUT generation module is used to generate a global data table LUT by back-solving the bicubic spline interpolation function according to iterative solution or numerical approximation method, to generate local data by back-solving the local bicubic spline interpolation function according to iterative solution or numerical approximation method, and to replace the global data table LUT with the corrected global data. The judgment module is used to input the global data table LUT into the bicubic spline interpolation function to obtain the corrected output points and to determine whether the accuracy requirements are met by calculating the error value between the corrected output points and the theoretical grid points. It is also used to select local areas based on the error results. The compensation and correction module is used to replace the data in the corresponding area of ​​the global data table LUT with local data and generate corrected global data by weighted fusion processing of the buffer between the local data and the global data table LUT. The marking control module is used to correct the galvanometer control signal according to the global data table LUT during the marking process, thereby outputting the corrected marking path.

[0050] The beneficial effects of this invention are as follows: by using bicubic spline interpolation, a small number of measurement points are expanded into a high-density global data table (LUT), ensuring the smoothness and accuracy of the entire area; when there are still dimensional errors in local areas (such as corner areas or certain key locations), the area can be remeasured and fitted separately to generate local data, which is then seamlessly spliced ​​with the global data table (LUT), maintaining the smoothness and transition accuracy of the galvanometer movement; local correction only applies to local areas, while other areas retain the original global correction results, avoiding overall destruction; it supports multiple iterative optimizations to gradually improve marking accuracy, enabling the grid size at non-measurement points to tend to be consistent with the theoretical value.

[0051] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A laser galvanometer distortion correction method based on bicubic spline interpolation, characterized in that, Includes the following steps: S1. Within the effective marking area of ​​the galvanometer, obtain several theoretical grid points and corresponding actual measurement points; S2. Construct a bicubic spline interpolation function based on the theoretical grid points and the actual measurement points; S3. Calculate the driving digital signal DA value corresponding to the target coordinates by reverse solving the bicubic spline interpolation function according to the iterative solution or numerical approximation method, and obtain the global data table LUT. S4. Input the global data table LUT into the bicubic spline interpolation function to obtain the corrected output points. Determine whether the accuracy requirements are met by calculating the error value between the corrected output points and the theoretical points. If yes, output the global data table LUT; otherwise, proceed to S5. S5. Local area compensation and correction, to obtain the global correction data, so that the global correction data replaces the global data table LUT, and then enters S4; The local region compensation and correction method described in S5 includes the following steps: S51. Based on the error value results, select a local area and re-measure at a higher resolution; S52. Construct a local bicubic spline interpolation function based on local area measurement data; S53. Use the local interpolation results to form local data, and replace the data in the corresponding area of ​​the global data table LUT with the local data; S54. By weighted fusion processing of the buffer between local data and global data table LUT, the corrected global data is obtained; The method for weighted fusion processing of the buffer between local data and global data table LUT as described in S54 includes the following steps: S541. Set the buffer width and divide the global data table LUT into the core area, buffer area and peripheral area; S542, Set the weights for each region ; ， in, S543. Divide the buffer into a left buffer, a lower buffer, a right buffer, and an upper buffer. Calculate the weight of each buffer. Then, multiply the weight of the left buffer by the weight of the lower buffer, and the weight of the right buffer by the weight of the upper buffer, respectively, to obtain the combined weight. Left buffer weights: ; Lower buffer weights: ; Right buffer weights: ; Upper buffer weights: ; Among them, the boundary of the core area W is the buffer width; S544, Based on comprehensive weighting Calculate the correction data within the buffer. ; Fusion formula: in, for .

2. The laser galvanometer distortion correction method based on bicubic spline interpolation according to claim 1, characterized in that, The method for constructing a bicubic spline interpolation function based on the theoretical grid points and actual measurement points, as described in S2, includes the following steps: S21. Divide the galvanometer calibration plane into a uniform rectangular grid, then divide the rectangular grid into rectangular elements, and in each rectangular element... Internally set bicubic spline interpolation basis functions in These are interpolation coefficients, a total of 16, with p ranging from 0 to 3 and q ranging from 0 to 3; S22. Calculate the interpolation coefficients in the bicubic spline interpolation basis function using the constraint equations of the bicubic spline interpolation and the actual measured point coordinates. Constraint equations: ，b= in, Node values, i.e., the coordinates of the actual measured points corresponding to the theoretical grid points within the rectangular element. First-order partial derivative in the x-direction First-order partial derivative in the y-direction, Let A be the mixed second-order partial derivative, A be the polynomial interpolation basis function matrix, a be the interpolation coefficients, and b be the boundary values; S23. Construct the bicubic spline interpolation function in the X direction and the bicubic spline interpolation function in the Y direction based on the interpolation coefficients; X-axis bicubic spline interpolation function: in, : Input X-axis and Y-axis drive signals; : X-channel interpolation coefficients of the k-th unit, a total of 16, p,q=0,1,2,3; Theoretical grid point coordinates; Y-axis bicubic spline interpolation function: in, : Input X-axis and Y-axis drive signals; : Y-channel interpolation coefficients of the k-th unit, a total of 16, p,q=0,1,2,3; Theoretical grid point coordinates.

3. The laser galvanometer distortion correction method based on bicubic spline interpolation according to claim 2, characterized in that... The method for calculating the first-order partial derivative in the x-direction is to construct a natural cubic spline along the X-direction using the coordinates of the actual measured points corresponding to the theoretical grid points within the rectangular unit as node values, and then calculate it using the Thomas algorithm.

4. The laser galvanometer distortion correction method based on bicubic spline interpolation according to claim 3, characterized in that, The method for calculating the first-order partial derivative in the y-direction is to construct a natural cubic spline along the y-direction using the coordinates of the actual measured points corresponding to the theoretical grid points within the rectangular unit as node values, and then calculate it using the Thomas algorithm.

5. The laser galvanometer distortion correction method based on bicubic spline interpolation according to claim 4, characterized in that, The method for calculating the hybrid second-order partial derivative is to derive it by cross-deriving the second-order derivative of the natural cubic spline based on the first-order derivative values ​​of each node in the X direction and the first-order derivative values ​​of each node in the Y direction.

6. The laser galvanometer distortion correction method based on bicubic spline interpolation according to claim 5, characterized in that, The method described in S3 for calculating the driving digital signal DA value corresponding to the target coordinates by inversely solving the bicubic spline interpolation function using iterative solutions or numerical approximation includes the following steps: S31, Set the target coordinates In the X-direction and Y-direction bicubic spline interpolation functions, and make... The driving digital signal corresponding to the target coordinates is calculated through iterative solution or numerical approximation. ; S32. Calculate the driving digital signal obtained in S31 according to the coordinate transformation DA formula. Corresponding DA value ; The coordinate transformation DA formula is as follows: ； ； Where Q is the correction area.

7. A laser galvanometer system, employing the laser galvanometer distortion correction method based on bicubic spline interpolation as described in any one of claims 1-6, characterized in that, The laser galvanometer system includes: The calibration data acquisition module is used to obtain theoretical grid points and actual measurement points; The interpolation calculation module is used to construct a bicubic spline interpolation function based on the theoretical grid points and the actual measurement points, and to construct a local bicubic spline interpolation function based on the measurement data of the local area. The LUT generation module is used to generate a global data table LUT by back-solving the bicubic spline interpolation function according to iterative solution or numerical approximation method, to generate local data by back-solving the local bicubic spline interpolation function according to iterative solution or numerical approximation method, and to replace the global data table LUT with the corrected global data. The judgment module is used to input the global data table LUT into the bicubic spline interpolation function to obtain the corrected output points and to determine whether the accuracy requirements are met by calculating the error value between the corrected output points and the theoretical grid points. It is also used to select local areas based on the error results. The compensation and correction module is used to replace the data in the corresponding area of ​​the global data table LUT with local data and generate corrected global data by weighted fusion processing of the buffer between the local data and the global data table LUT; and The marking control module is used to correct the galvanometer control signal according to the global data table LUT during the marking process, thereby outputting the corrected marking path.

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