A compensation method for high-precision two-dimensional motion system

Abstract

The present invention relates to motion control, and in particular to a compensation method for a high-precision two-dimensional motion system. The motion control system sets the motion system to move to a desired coordinate point in an ideal coordinate system, first determines the position of the desired coordinate point in a theoretical target array LCS, then obtains the corresponding transformation matrix MMS from an application compensation table, and uses the transformation matrix MMS to calculate the actual coordinate point of the desired coordinate point in a two-dimensional coordinate sequence MCS; the motion control system obtains corresponding deviation compensation values ​​from an X-axis motion deviation compensation table and a Y-axis motion deviation compensation table according to the positions of the actual coordinate point on the X-axis and Y-axis, calculates the final compensation value using a linear interpolation method, and superimposes the final compensation value on the actual coordinate point to generate the final coordinate point; the technical solution provided by the present invention can effectively overcome the defects of low compensation accuracy for the motion of a two-dimensional motion system and a relatively fixed compensation algorithm, resulting in the equipment accuracy indicators being unable to meet the requirements of high-precision production.

Description

Technical Field

[0001] The present invention relates to motion control, and in particular to a compensation method for a high-precision two-dimensional motion system. Background Art

[0002] Motion control technology is a multidisciplinary, complex technology encompassing mechanics and electronics, hardware and software, algorithms, and analysis. For various high-precision devices, the accuracy of the two-dimensional motion system often plays a decisive role in determining the device's precision. However, existing high-precision devices have low compensation accuracy for two-dimensional motion systems and relatively fixed compensation algorithms, typically using linear interpolation-based compensation methods. This results in low trajectory accuracy for the two-dimensional motion system, and consequently, the device's precision cannot meet the requirements of high-precision production. Summary of the Invention

[0003] (1) Technical problems solved

[0004] In response to the above-mentioned shortcomings of the existing technology, the present invention provides a compensation method for a high-precision two-dimensional motion system, which can effectively overcome the defects of the existing technology in that the compensation accuracy of the two-dimensional motion system is low and the compensation algorithm is relatively fixed, resulting in the equipment accuracy indicators being unable to meet the high-precision production requirements.

[0005] (2) Technical solution

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A high-precision compensation method for a two-dimensional motion system is proposed. The motion control system sets the motion system to move to a desired coordinate point in an ideal coordinate system. The position of the desired coordinate point in a theoretical target array (LCS) is first determined. The corresponding transformation matrix (MMS) is then obtained from an application compensation table. The actual coordinate point of the desired coordinate point in the two-dimensional coordinate sequence (MCS) is calculated using the transformation matrix (MMS).

[0008] The motion control system obtains the corresponding deviation compensation value from the X-axis motion deviation compensation table and the Y-axis motion deviation compensation table according to the position of the actual coordinate point on the X-axis and Y-axis, respectively, calculates the final compensation value using linear interpolation, and superimposes it on the actual coordinate point to generate the final coordinate point.

[0009] Preferably, the method for establishing the X-axis motion deviation compensation table and the Y-axis motion deviation compensation table includes:

[0010] S11. A CCD camera is fixedly placed above the motion system, and a standard plate having an array of targets periodically arranged at equal intervals is placed at the center of the motion platform of the motion system;

[0011] S12, locating the center point of the motion platform, and determining target arrays MS_X and MS_Y on the standard plate that are parallel to the X-axis and Y-axis respectively based on the center point of the motion platform. The intersection of the target arrays MS_X and MS_Y is the center intersection target P;

[0012] S13, using a CCD camera to capture the coordinates of the center point of each target in the target array MS_X, MS_Y in the ideal coordinate system, and respectively generate a coordinate sequence MC_X, MC_Y, and a coordinate PC corresponding to the center intersection target P;

[0013] S14 , establishing an X-axis motion deviation compensation table and a Y-axis motion deviation compensation table based on the coordinate sequence MC_X, MC_Y, and the coordinate PC corresponding to the center intersection target P.

[0014] Preferably, in S14, an X-axis motion deviation compensation table and a Y-axis motion deviation compensation table are established based on the coordinate sequences MC_X and MC_Y and the coordinate PC corresponding to the center intersection target P, including:

[0015] S141, obtaining a straight line LX of the coordinate sequence MC_X passing through the coordinate PC by linear fitting;

[0016] S142, taking the point with the minimum horizontal coordinate in the coordinate sequence MC_X as the starting point, and calculating the theoretical target center arrangement sequence LC_X based on the theoretical interval period of the standard plate in the positive direction of the straight line LX;

[0017] S143, calculating the difference between the horizontal coordinate value of each point in the coordinate sequence MC_X and the horizontal coordinate value of the corresponding point in the theoretical target center arrangement sequence LC_X, to obtain a length deviation value sequence D_X;

[0018] S144, calculating the difference between the ordinate value of each point in the coordinate sequence MC_X and the ordinate value of the corresponding point in the theoretical target center arrangement sequence LC_X, to obtain an offset deviation value sequence Y_X;

[0019] S145. Repeat the process from S141 to S144 for the coordinate sequence MC_Y to obtain a length deviation value sequence D_Y and an offset deviation value sequence Y_Y respectively;

[0020] S146, superimposing the length deviation value sequence D_X and the offset deviation value sequence Y_Y, and loading the superimposed result into the motion control system as an X-axis motion deviation compensation table;

[0021] S147 , superimposing the offset deviation value sequence Y_X and the length deviation value sequence D_Y, and loading the superimposed result into the motion control system as a Y-axis motion deviation compensation table.

[0022] Preferably, the method for establishing the application compensation table includes:

[0023] S21. A CCD camera is fixedly placed above the motion system, and a standard plate having an array of targets periodically arranged at equal intervals is placed at the center of the motion platform of the motion system;

[0024] S22, using a CCD camera to capture the coordinates of the center point of each target in the target array on the standard plate in the ideal coordinate system, and generating a two-dimensional coordinate sequence MCS;

[0025] S23, selecting the point closest to the central intersection target P from the two-dimensional coordinate sequence MCS as the central reference point P0, and obtaining a straight line L of the two-dimensional coordinate sequence MCS passing through the central reference point P0 by linear fitting;

[0026] S24, using the central reference point P0 and the straight line L as references and combining the theoretical interval period of the standard plate, generating a theoretical target array LCS;

[0027] S25. Establish an application compensation table based on the two-dimensional coordinate sequence MCS and the theoretical target array LCS.

[0028] Preferably, in S25, establishing an application compensation table based on the two-dimensional coordinate sequence MCS and the theoretical target array LCS includes:

[0029] S251, matching the points in the two-dimensional coordinate sequence MCS and the theoretical target array LCS one by one;

[0030] S252, performing projection transformation fitting on a quadrilateral formed by each of the four points to generate multiple transformation matrices MMS;

[0031] S253 , associating the multiple transformation matrices MMS with the corresponding theoretical target arrays LCS, and loading them into the motion control system as an application compensation table.

[0032] (3) Beneficial effects

[0033] Compared with the prior art, the compensation method for a high-precision two-dimensional motion system provided by the present invention has the following beneficial effects:

[0034] 1) Through a specific two-dimensional motion system motion compensation method, the two-dimensional motion system can have a higher-precision motion trajectory, which can significantly improve the overall accuracy of the equipment in devices that require high-precision motion;

[0035] 2) The deviation compensation table is loaded into the embedded motion control system. The compensation algorithm is simple and has high real-time performance. It is used for real-time compensation of linear motion processes, effectively improving the motion trajectory accuracy of the two-dimensional motion system.

[0036] 3) The application software is responsible for applying the compensation table, and various complex compensation algorithms can be used to further improve the control accuracy of fixed-point motion. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0038] Figure 1 It is a schematic diagram of the process of the present invention;

[0039] Figure 2 It is a structural schematic diagram of the present invention;

[0040] Figure 3 Schematic diagram of target arrays MS_X, MS_Y, and center intersection target P in the present invention;

[0041] Figure 4 Schematic diagram of obtaining the straight line LX of the coordinate sequence MC_X passing through the coordinate PC by straight line fitting in the present invention;

[0042] Figure 5 Schematic diagram of generating the transformation matrix MMS based on the two-dimensional coordinate sequence MCS and the theoretical target array LCS in the present invention. DETAILED DESCRIPTION

[0043] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0044] A compensation method for high-precision two-dimensional motion systems, such as Figure 1 As shown, the motion control system sets the motion system to move to the desired coordinate point in the ideal coordinate system. First, the position of the desired coordinate point in the theoretical target array LCS is determined, and then the corresponding transformation matrix MMS is obtained from the application compensation table. The actual coordinate point of the desired coordinate point in the two-dimensional coordinate sequence MCS is calculated using the transformation matrix MMS.

[0045] The motion control system obtains the corresponding deviation compensation value from the X-axis motion deviation compensation table and the Y-axis motion deviation compensation table according to the position of the actual coordinate point on the X-axis and Y-axis, respectively, calculates the final compensation value using linear interpolation, and superimposes it on the actual coordinate point to generate the final coordinate point.

[0046] In the above technical solution, a specific two-dimensional motion system motion compensation method is used to enable the two-dimensional motion system to have a more precise motion trajectory, thereby significantly improving the overall accuracy of the device in devices that require high-precision motion.

[0047] 1) The method for establishing the X-axis motion deviation compensation table and the Y-axis motion deviation compensation table includes:

[0048] S11. A CCD camera is fixedly placed above the motion system, and a standard plate having an array of targets periodically arranged at equal intervals is placed at the center of the motion platform of the motion system;

[0049] S12, locate the center point of the motion platform, and determine the target arrays MS_X and MS_Y on the standard plate that are parallel to the X axis and Y axis respectively according to the center point of the motion platform. The intersection of the target arrays MS_X and MS_Y is the center intersection target P (such as Figure 3 shown);

[0050] S13, using a CCD camera to capture the coordinates of the center point of each target in the target array MS_X, MS_Y in the ideal coordinate system, and respectively generate a coordinate sequence MC_X, MC_Y, and a coordinate PC corresponding to the center intersection target P;

[0051] S14 , establishing an X-axis motion deviation compensation table and a Y-axis motion deviation compensation table based on the coordinate sequence MC_X, MC_Y, and the coordinate PC corresponding to the center intersection target P.

[0052] The X-axis motion deviation compensation table and the Y-axis motion deviation compensation table are established based on the coordinate sequence MC_X, MC_Y, and the coordinate PC corresponding to the center intersection target P, specifically including:

[0053] S141, by linear fitting (the corresponding linear fitting algorithm can be selected according to the accuracy requirement, such as the least square method), a straight line LX (such as Figure 4 shown);

[0054] S142, taking the point with the minimum horizontal coordinate in the coordinate sequence MC_X as the starting point, and calculating the theoretical target center arrangement sequence LC_X based on the theoretical interval period of the standard plate in the positive direction of the straight line LX;

[0055] S143, calculating the difference between the horizontal coordinate value of each point in the coordinate sequence MC_X and the horizontal coordinate value of the corresponding point in the theoretical target center arrangement sequence LC_X, to obtain a length deviation value sequence D_X;

[0056] S144, calculating the difference between the ordinate value of each point in the coordinate sequence MC_X and the ordinate value of the corresponding point in the theoretical target center arrangement sequence LC_X, to obtain an offset deviation value sequence Y_X;

[0057] S145. Repeat the process from S141 to S144 for the coordinate sequence MC_Y to obtain a length deviation value sequence D_Y and an offset deviation value sequence Y_Y respectively;

[0058] S146, superimposing the length deviation value sequence D_X and the offset deviation value sequence Y_Y, and loading the superimposed result into the motion control system as an X-axis motion deviation compensation table;

[0059] S147 , superimposing the offset deviation value sequence Y_X and the length deviation value sequence D_Y, and loading the superimposed result into the motion control system as a Y-axis motion deviation compensation table.

[0060] Table 1 Example table of offset deviation value sequence Y_X

[0061] X 0 10 20 30 40 dy 0.003 0.005 0.001 -0.002 -0.006

[0062] Table 2 Example table of length deviation value sequence D_Y

[0063] Y 0 10 20 30 40 dy -0.002 -0.001 0.003 0.004 0.002

[0064] Table 3 Y-axis motion deviation compensation table

[0065]

[0066] In the above technical solution, the deviation compensation table is loaded into the embedded motion control system. The compensation algorithm is simple and has high real-time performance. It is used for real-time compensation of linear motion processes, effectively improving the motion trajectory accuracy of the two-dimensional motion system.

[0067] 2) A method for establishing an application compensation table, including:

[0068] S21. A CCD camera is fixedly placed above the motion system, and a standard plate having an array of targets periodically arranged at equal intervals is placed at the center of the motion platform of the motion system;

[0069] S22, using a CCD camera to capture the coordinates of the center point of each target in the target array on the standard plate in the ideal coordinate system, and generating a two-dimensional coordinate sequence MCS;

[0070] S23, selecting the point closest to the central intersection target P from the two-dimensional coordinate sequence MCS as the central reference point P0, and obtaining a straight line L of the two-dimensional coordinate sequence MCS passing through the central reference point P0 by linear fitting;

[0071] S24, using the central reference point P0 and the straight line L as references and combining the theoretical interval period of the standard plate, generating a theoretical target array LCS;

[0072] S25. Establish an application compensation table based on the two-dimensional coordinate sequence MCS and the theoretical target array LCS.

[0073] Among them, an application compensation table is established based on the two-dimensional coordinate sequence MCS and the theoretical target array LCS, specifically including:

[0074] S251, matching the points in the two-dimensional coordinate sequence MCS and the theoretical target array LCS one by one;

[0075] S252, perform projection transformation fitting on the quadrilateral formed by each four points to generate multiple transformation matrices MMS (such as Figure 5 shown);

[0076] S253 , associating the multiple transformation matrices MMS with the corresponding theoretical target arrays LCS, and loading them into the motion control system as an application compensation table.

[0077] In the above technical solution, the application software is responsible for applying the compensation table, and various complex compensation algorithms can be used to further improve the control accuracy of fixed-point motion.

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A compensation method for a high-precision two-dimensional motion system, characterized by: The motion control system sets the motion system to move to the desired coordinate point in the ideal coordinate system. First, the position of the desired coordinate point in the theoretical target array LCS is determined. Then, the corresponding transformation matrix MMS is obtained from the application compensation table. The actual coordinate point of the desired coordinate point in the two-dimensional coordinate sequence MCS is calculated using the transformation matrix MMS. The motion control system obtains the corresponding deviation compensation value from the X-axis motion deviation compensation table and the Y-axis motion deviation compensation table according to the actual coordinate point's position on the X-axis and Y-axis, respectively, calculates the final compensation value using linear interpolation, and superimposes it on the actual coordinate point to generate the final coordinate point; The method for establishing the application compensation table includes: S21. A CCD camera is fixedly placed above the motion system, and a standard plate having an array of targets periodically arranged at equal intervals is placed at the center of the motion platform of the motion system; S22, using a CCD camera to capture the coordinates of the center point of each target in the target array on the standard plate in the ideal coordinate system, and generating a two-dimensional coordinate sequence MCS; S23. Select the point closest to the center intersection target P from the two-dimensional coordinate sequence MCS as the center reference point P0. Determine target arrays MS_X and MS_Y on the standard plate that are parallel to the X-axis and Y-axis, respectively, based on the center point of the motion platform. The intersection of the target arrays MS_X and MS_Y is the center intersection target P. Obtain a straight line L through the center reference point P0 of the two-dimensional coordinate sequence MCS by linear fitting. S24, using the central reference point P0 and the straight line L as references and combining the theoretical interval period of the standard plate, generating a theoretical target array LCS; S25, establishing an application compensation table based on the two-dimensional coordinate sequence MCS and the theoretical target array LCS; In S25, an application compensation table is established based on the two-dimensional coordinate sequence MCS and the theoretical target array LCS, including: S251, matching the points in the two-dimensional coordinate sequence MCS and the theoretical target array LCS one by one; S252, performing projection transformation fitting on a quadrilateral formed by each of the four points to generate multiple transformation matrices MMS; S253 , associating the multiple transformation matrices MMS with the corresponding theoretical target arrays LCS, and loading them into the motion control system as an application compensation table.

2. The compensation method for a high-precision two-dimensional motion system according to claim 1, characterized in that: The method for establishing the X-axis motion deviation compensation table and the Y-axis motion deviation compensation table includes: S11. A CCD camera is fixedly placed above the motion system, and a standard plate having an array of targets periodically arranged at equal intervals is placed at the center of the motion platform of the motion system; S12, locating the center point of the motion platform, and determining target arrays MS_X and MS_Y on the standard plate that are parallel to the X-axis and Y-axis respectively based on the center point of the motion platform. The intersection of the target arrays MS_X and MS_Y is the center intersection target P; S13, using a CCD camera to capture the coordinates of the center point of each target in the target array MS_X, MS_Y in the ideal coordinate system, and respectively generate a coordinate sequence MC_X, MC_Y, and a coordinate PC corresponding to the center intersection target P; S14 , establishing an X-axis motion deviation compensation table and a Y-axis motion deviation compensation table based on the coordinate sequence MC_X, MC_Y, and the coordinate PC corresponding to the center intersection target P.

3. The compensation method for a high-precision two-dimensional motion system according to claim 2, characterized in that: In S14, an X-axis motion deviation compensation table and a Y-axis motion deviation compensation table are established based on the coordinate sequence MC_X, MC_Y and the coordinate PC corresponding to the center intersection target P, including: S141, obtaining a straight line LX of the coordinate sequence MC_X passing through the coordinate PC by linear fitting; S142, taking the point with the minimum horizontal coordinate in the coordinate sequence MC_X as the starting point, and calculating the theoretical target center arrangement sequence LC_X based on the theoretical interval period of the standard plate in the positive direction of the straight line LX; S143, calculating the difference between the horizontal coordinate value of each point in the coordinate sequence MC_X and the horizontal coordinate value of the corresponding point in the theoretical target center arrangement sequence LC_X, to obtain a length deviation value sequence D_X; S144, calculating the difference between the ordinate value of each point in the coordinate sequence MC_X and the ordinate value of the corresponding point in the theoretical target center arrangement sequence LC_X, to obtain an offset deviation value sequence Y_X; S145. Repeat the process from S141 to S144 for the coordinate sequence MC_Y to obtain a length deviation value sequence D_Y and an offset deviation value sequence Y_Y respectively; S146, superimposing the length deviation value sequence D_X and the offset deviation value sequence Y_Y, and loading the superimposed result into the motion control system as an X-axis motion deviation compensation table; S147 , superimposing the offset deviation value sequence Y_X and the length deviation value sequence D_Y, and loading the superimposed result into the motion control system as a Y-axis motion deviation compensation table.

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