Geometric error calibration method and device, multi-axis motion system and storage medium

Abstract

The application discloses a kind of geometric error calibration method, device, multi-axis motion system and storage medium, it is related to multi-axis motion system technical field, method includes: according to user operation instruction manual calibration, obtains the initial corresponding relationship between the mechanical coordinate system of multi-axis motion system and the calibration coordinate system of calibration plate;According to initial corresponding relationship, target acquisition point based on calibration plate and the target pose of visual camera, determine corresponding target calibration point on mechanical coordinate system;According to target calibration point generation automatic calibration instruction;According to automatic calibration instruction, control visual camera and target calibration point carry out point operation, obtain the final corresponding relationship between mechanical coordinate system and calibration coordinate system.The application solves the problem that the geometric error calibration of existing multi-axis motion system is lower in efficiency, realizes the effect that multi-axis motion system is geometrically error calibrated automatically, quickly and efficiently.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of multi-axis motion system, and in particular to a geometric error calibration method and device of a multi-axis motion system, a multi-axis motion system and a storage medium. BACKGROUND

[0002] With the continuous upgrading of modern mechanical manufacturing technology, the complexity, precision and process requirements of product processing are becoming higher and higher. Especially in terms of machining precision, more and more occasions require spatial positioning precision to be improved to the micron or even sub-micron level. In most mechanical equipment with multi-axis motion systems, the spatial positioning precision requirement of the multi-axis motion system is mainly reflected in the three-dimensional spatial positioning of the end of the working part.

[0003] In order to achieve micron-level positioning precision control of the multi-axis motion system, hundreds of sets of corresponding coordinate data are often needed to calibrate the geometric error of the multi-axis motion system. The current geometric error calibration method is to obtain the hundreds of sets of corresponding coordinate data through manual calibration. This method has a very cumbersome operation process and often takes tens of hours, which greatly affects the work efficiency. SUMMARY

[0004] The main purpose of the present application is to provide a geometric error calibration method, device, multi-axis motion system and storage medium, which aims to solve the technical problem of low efficiency in geometric error calibration of the multi-axis motion system in the prior art.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] In a first aspect, the present application provides a geometric error calibration method, which is used for a multi-axis motion system, the multi-axis motion system comprising a working part and a workbench, a vision camera being arranged on the working part, and a calibration board being arranged on the workbench, the method comprising:

[0007] manually calibrating according to a user operation instruction to obtain an initial correspondence relationship between a mechanical coordinate system of the multi-axis motion system and a calibration coordinate system of the calibration board;

[0008] determining a target calibration point corresponding on the mechanical coordinate system according to the initial correspondence relationship, a target collection point based on the calibration board and a target pose of the vision camera;

[0009] generating an automatic calibration instruction according to the target calibration point;

[0010] controlling the vision camera to perform a point matching operation on the target calibration point according to the automatic calibration instruction to obtain a final correspondence relationship between the mechanical coordinate system and the calibration coordinate system.

[0011] Optionally, in the geometric error calibration method, the manual calibration according to the user operation instruction to obtain the initial correspondence between the mechanical coordinate system of the multi-axis motion system and the calibration coordinate system of the calibration plate comprises:

[0012] obtaining a user operation instruction;

[0013] controlling the vision camera to perform point matching on the mark blocks on the calibration plate in different poses in a preset number according to the user operation instruction;

[0014] when the visual intersection of the vision camera coincides with the center point of the mark block, recording a first coordinate pair composed of the mechanical coordinate system coordinate of the multi-axis motion system and the coordinate of the mark block on the calibration coordinate system of the calibration plate;

[0015] obtaining the initial correspondence between the mechanical coordinate system of the multi-axis motion system and the calibration coordinate system of the calibration plate through a spatial geometric algorithm according to the first coordinate pair in the preset number.

[0016] Optionally, in the geometric error calibration method, the determination of the target calibration point on the mechanical coordinate system according to the initial correspondence, the target acquisition point based on the calibration plate, and the target pose of the vision camera comprises:

[0017] determining a target pose of the vision camera, two-dimensional acquisition points in a preset region on the calibration plate, and three-dimensional acquisition points relative to the calibration plate, wherein the target pose comprises a plurality of poses uniformly distributed at equal angles;

[0018] obtaining a target acquisition point based on the calibration plate according to the two-dimensional acquisition points and the three-dimensional acquisition points;

[0019] converting the target acquisition point into a coordinate on the mechanical coordinate system under the target pose according to the initial correspondence to obtain the target calibration point.

[0020] Optionally, in the geometric error calibration method, the determination of the two-dimensional acquisition points in the preset region on the calibration plate comprises:

[0021] determining N acquisition points in a first quadrant of the calibration coordinate system in a preset region of the calibration plate, N≥1, wherein the first quadrant is any quadrant of the calibration coordinate system;

[0022] determining N acquisition points in a second quadrant and N acquisition points in a fourth quadrant of the N acquisition points symmetrical about any coordinate axis of the calibration coordinate system, and N acquisition points in a third quadrant symmetrical about any coordinate axis of the calibration coordinate system of the N acquisition points in the second quadrant or the N acquisition points in the fourth quadrant.

[0023] According to the N acquisition points of the first quadrant, the N acquisition points of the second quadrant, the N acquisition points of the third quadrant, the N acquisition points of the fourth quadrant, and the coordinate origin of the calibration coordinate system, 4N+1 two-dimensional acquisition points are obtained.

[0024] Optionally, in the geometric error calibration method, the determination of the three-dimensional acquisition points relative to the calibration board comprises:

[0025] determining M initial acquisition points on the calibration board and an arbitrary pose of the vision camera, M≥1 and M<4N+1;

[0026] for each initial acquisition point, controlling the vision camera to perform a point operation in the arbitrary pose;

[0027] when the visual intersection point of the vision camera coincides with the initial acquisition point, moving the initial acquisition point by a preset distance along a three-dimensional direction perpendicular to the calibration board to obtain M three-dimensional acquisition points, wherein the preset distance is set based on the visibility of the initial acquisition point in the visual range of the vision camera.

[0028] Optionally, in the geometric error calibration method, the conversion of the target acquisition point into a coordinate on the mechanical coordinate system under the target pose according to the initial correspondence relationship to obtain the target calibration point comprises:

[0029] determining a coordinate on the mechanical coordinate system corresponding to the target acquisition point under the target pose according to the initial correspondence relationship;

[0030] according to the coordinate on the mechanical coordinate system corresponding to the target acquisition point, converting to obtain coordinate values on the mechanical coordinate system of each axis in the multi-axis motion system to obtain the target calibration point.

[0031] Optionally, in the geometric error calibration method, the control of the vision camera to perform a point operation on the target calibration point according to the automatic calibration instruction to obtain the final correspondence relationship between the mechanical coordinate system and the calibration coordinate system comprises:

[0032] controlling the vision camera to perform a point operation on the target calibration point in the target pose according to the automatic calibration instruction;

[0033] when the visual intersection point of the vision camera coincides with the target calibration point, recording a second coordinate pair composed of the mechanical coordinate system coordinate of the multi-axis motion system and the coordinate of the target calibration point on the calibration coordinate system;

[0034] According to the second coordinate pair, a final correspondence relationship between the mechanical coordinate system and the calibration coordinate system is obtained through a spatial geometry algorithm.

[0035] In a second aspect, the present application provides a geometric error calibration device, which is used in a multi-axis motion system including a work component and a worktable, the work component is provided with a vision camera, and the worktable is provided with a calibration board, and the device includes:

[0036] An initial calibration module is configured to perform manual calibration according to a user operation instruction to obtain an initial correspondence relationship between a mechanical coordinate system of the multi-axis motion system and a calibration coordinate system of the calibration board;

[0037] A target determination module is configured to determine a target calibration point corresponding on the mechanical coordinate system according to the initial correspondence relationship, based on a target collection point of the calibration board and a target pose of the vision camera;

[0038] An instruction generation module is configured to generate an automatic calibration instruction according to the target calibration point;

[0039] An automatic calibration module is configured to control the vision camera to perform a point matching operation on the target calibration point according to the automatic calibration instruction to obtain a final correspondence relationship between the mechanical coordinate system and the calibration coordinate system.

[0040] In a third aspect, the present application provides a multi-axis motion system, which includes:

[0041] A work component is provided with a vision camera;

[0042] A worktable is provided with a calibration board;

[0043] A control device includes a processor and a memory, and the memory is stored with a geometric error calibration program, and the geometric error calibration program is executed by the processor to realize the geometric error calibration method as described above.

[0044] In a fourth aspect, the present application provides a computer readable storage medium, which is stored with a computer program, and the computer program is executed by one or more processors to realize the geometric error calibration method as described above.

[0045] The above one or more technical solutions provided by the present application can have the following advantages or at least achieve the following technical effects:

[0046] The application provides a geometric error calibration method and device, a multi-axis motion system and a storage medium. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0048] Figure 1 The flowchart of the geometric error calibration method of the present application is shown in the figure.

[0049] Figure 2 The hardware structure diagram of the control device in the multi-axis motion system of the present application is shown in the figure.

[0050] Figure 3 The function module diagram of the geometric error calibration device of the present application is shown in the figure.

[0051] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0053] It should be noted that, in the present application, the terms "comprising", "including", or any other variant thereof are intended to cover a non-exclusive inclusion, such that processes, methods, articles, or systems that comprise a list of elements not only include those elements, but also include other elements not expressly listed or inherent to such processes, methods, articles, or systems. Without more limitations, the elements defined by the statement "comprise" do not exclude the presence of additional identical elements in the process, method, article, or system that includes the element. In the present application, if there is a description involving "first", "second", etc., the description of "first", "second", etc. is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the present application, the suffix such as "module", "component" or "unit" used to represent an element is only for the convenience of the description of the present application, and has no specific meaning. Therefore, "module", "component" or "unit" can be used interchangeably. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. In addition, the technical solutions of various embodiments can be combined with each other, but it is based on the fact that the technical solutions can be realized by those skilled in the art. When the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist, and is not within the scope of protection required by the present application.

[0054] With the continuous upgrading of modern mechanical manufacturing technology, the complexity, precision, process and other requirements of product processing are becoming higher and higher. Especially in terms of machining precision, more and more occasions require spatial positioning precision to be improved to microns or even sub-microns. However, due to the influence of many factors such as the current mechanical development level, equipment assembly precision and detection precision, most of the mechanical equipment on the market is increasingly unable to meet the precision requirements of spatial positioning.

[0055] Although, there are some devices in the prior art that can meet the spatial positioning accuracy requirements, such as high-precision machine tools with high prices; devices that use full closed-loop control technology to individually compensate for multi-axis errors; and devices that use laser interferometers or ball bar instruments to measure single-axis and multi-axis absolute errors, perpendicular errors, etc., and then use a host computer for command compensation. These devices can meet the spatial positioning accuracy requirements, but they have some other problems, such as high-precision machine tools, which have high prices, high maintenance costs, and require high-quality technical personnel, increasing production costs; full closed-loop control technology and laser interferometer devices can only meet the accuracy requirements of single-axis absolute position, but cannot meet the multi-axis coordination accuracy requirements such as perpendicularity and parallelism; ball bar devices cannot solve the clamping error problem and require high-end host computers for command compensation. Therefore, the existing devices that can meet the spatial positioning accuracy requirements are not suitable for most actual application scenarios due to the high economic cost and high technical requirements. Based on this, improvements are made to most existing devices that cannot meet the spatial positioning accuracy requirements, so that they can meet the spatial positioning accuracy requirements, saving costs and meeting the needs of actual applications.

[0056] Analysis of the prior art shows that most multi-axis motion systems in mechanical devices such as multi-axis machine tools and multi-joint robots require spatial positioning accuracy, which mainly reflects in the three-dimensional spatial positioning of the end of the workpiece, such as the tip of a metal processing tool, the clamping point of a multi-joint robot, and the dispensing head of a dispensing machine. To enable low-precision multi-axis motion systems to meet high-precision usage requirements, it is necessary to establish a correspondence between the mechanical coordinate system of the multi-axis motion system and the standard spatial coordinate system, and to solve the actual kinematics of the multi-axis motion system using a number of corresponding coordinate data with the standard spatial coordinate system as the reference. Then, when performing three-dimensional spatial positioning at the end of the workpiece, the original command coordinate values are treated as coordinate values in the standard spatial coordinate system, and the original command coordinate values are converted to result coordinate values in the corresponding multi-axis motion system mechanical coordinate system according to the actual kinematics of the multi-axis motion system. The host computer can then control the multi-axis motion system to move to the result coordinate values, thereby achieving high-precision positioning of the workpiece in three-dimensional space. In this process, the process of establishing a correspondence between the mechanical coordinate system of the multi-axis motion system and the standard spatial coordinate system and obtaining a number of corresponding coordinate data is "calibration".

[0057] In order to realize the micron-level positioning accuracy control of the multi-axis motion system, hundreds of corresponding coordinate data are often needed to calibrate the geometric error of the multi-axis motion system. The current geometric error calibration method is to obtain the hundreds of corresponding coordinate data through manual calibration. The operation process of this method is very cumbersome, often takes tens of hours, greatly affects the work efficiency, and also affects the ease of use of the geometric error compensation scheme of the multi-axis motion system.

[0058] In view of the technical problem of low efficiency in the geometric error calibration of the multi-axis motion system in the prior art, the present application provides a geometric error calibration method, the general idea is as follows:

[0059] According to the user operation instruction, manual calibration is performed to obtain the initial correspondence relationship between the mechanical coordinate system of the multi-axis motion system and the calibration coordinate system of the calibration plate; according to the initial correspondence relationship, the target collection point based on the calibration plate and the target pose of the vision camera, the corresponding target calibration point on the mechanical coordinate system is determined; according to the target calibration point, an automatic calibration instruction is generated; according to the automatic calibration instruction, the vision camera is controlled to operate the point on the target calibration point, and the final correspondence relationship between the mechanical coordinate system and the calibration coordinate system is obtained.

[0060] Through the above technical solution, the purpose of manually roughly calibrating and then automatically accurately calibrating the geometric error existing in the multi-axis motion system is achieved. Compared with the prior art, the present application combines automatic calibration on the basis of manual calibration, not only simplifies the manual operation process in the whole calibration process, but also improves the accuracy of calibration, so that the conventional multi-axis motion system can also meet the more stringent spatial positioning accuracy requirements, increases the applicability of the system, and thus improves the ease of use of the subsequent geometric error compensation scheme of the system.

[0061] The geometric error calibration method, device, multi-axis motion system and storage medium provided by the present application will be described in detail below with reference to the accompanying drawings, specific embodiments and implementation modes.

[0062] Embodiment one

[0063] Referring to Figure 1 the flowchart, the first embodiment of the geometric error calibration method of the present application is proposed, and the geometric error calibration method is applied to a multi-axis motion system.

[0064] The multi-axis motion system refers to a comprehensive system with multiple mechanical transmission shafts, which controls the synchronous movement of the working parts on the multiple mechanical transmission shafts through a control device to perform respective operations, such as multi-axis machine tools, multi-joint robots, etc.

[0065] In this embodiment, the multi-axis motion system can include a work component, a workbench, and a control device. The work component is provided with a vision camera, the workbench is provided with a calibration board, and the control device is a control device that coordinates and controls the hardware and software structure of the entire system around complex motion, which can be a terminal device such as an embedded industrial computer, or a device such as a controller and a processor.

[0066] As shown in Figure 2 , it is a schematic diagram of the hardware structure of the control device. The control device can include a processor 1001 such as a CPU (Central Processing Unit), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. Those skilled in the art can understand that the hardware structure shown in Figure 2 does not constitute a limitation on the multi-axis motion system of the present application, and can include more or fewer components than shown, or combine certain components, or different component arrangements.

[0067] Specifically, the communication bus 1002 is used to realize the connection and communication between the components; the user interface 1003 is used to connect the client and communicate data with the client, and the user interface 1003 can include an output unit such as a display screen and an input unit such as a keyboard; the network interface 1004 is used to connect the background server and communicate data with the background server, and the network interface 1004 can include an input / output interface such as a standard wired interface and a wireless interface such as a Wi-Fi interface; the memory 1005 is used to store various types of data, which can include, for example, instructions of any application program or method in the control device, and application-related data, and the memory 1005 can be a high-speed RAM memory or a stable memory such as a disk memory; optionally, the memory 1005 can also be a storage device independent of the processor 1001, and referring to Figure 2 , the memory 1005 can include an operating system, a network communication module, a user interface module, and a geometric error calibration program; the processor 1001 is used to call the geometric error calibration program stored in the memory 1005 and perform the following operations:

[0068] According to the user operation instruction, manual calibration is performed to obtain an initial correspondence relationship between the mechanical coordinate system of the multi-axis motion system and the calibration coordinate system of the calibration board;

[0069] According to the initial correspondence relationship, the target acquisition point based on the calibration board, and the target pose of the vision camera, a corresponding target calibration point on the mechanical coordinate system is determined;

[0070] An automatic calibration instruction is generated according to the target calibration point;

[0071] According to the automatic calibration instruction, the visual camera is controlled to perform point matching operation on the target calibration points to obtain the final corresponding relationship between the mechanical coordinate system and the calibration coordinate system.

[0072] Based on the multi-axis motion system described above, the geometric error calibration method of the present embodiment will be described in detail below with reference to the flowchart shown in Figure 1 The method can include the following steps:

[0073] Step S100: According to the user operation instruction, manual calibration is performed to obtain the initial corresponding relationship between the mechanical coordinate system of the multi-axis motion system and the calibration coordinate system of the calibration plate.

[0074] Specifically, the purpose of this step S100 is to manually measure a small number of corresponding points to calculate the rough spatial relationship between the multi-axis motion system and the calibration plate. The small number of corresponding points can be a small number of points or coordinate point pairs corresponding to the multi-axis motion system coordinate values and the calibration plate coordinate values. The rough spatial relationship can be the approximate spatial relationship between the mechanical coordinate system of the multi-axis motion system and the calibration coordinate system of the calibration plate, i.e. the initial corresponding relationship.

[0075] In one embodiment, step S100 can include:

[0076] Step S110: Obtain a user operation instruction.

[0077] Specifically, the multi-axis motion system carries a vision system, and a visual camera is arranged on the working component of the vision system, which is uniformly controlled by a control device. The worktable of the multi-axis motion system carries a customized calibration plate with coordinate information, and the calibration coordinate system of the calibration plate can be regarded as a standard spatial coordinate system. The calibration plate has a plurality of Mark blocks, and the center point of each Mark block based on the coordinates of the calibration coordinate system is the coordinates of the Mark block. The size of the calibration plate is in appropriate proportion to the effective range of the worktable, for example, the size of the calibration plate is exactly one fifth of the effective range of the worktable, and the specific proportion can be set according to the actual situation, which is not limited here. The calibration plate is a two-dimensional plane, so the calibration coordinate system is a two-dimensional coordinate system. The multi-axis motion system has multiple axial movements, and its mechanical coordinate system is a three-dimensional coordinate system.

[0078] Step S120: According to the user operation instruction, the visual camera is controlled to perform point matching operation on the mark blocks on the calibration plate in different poses in a preset number.

[0079] Specifically, the user operation instruction can be an operation instruction generated by the control device after the user directly performs a control operation on the control panel of the multi-axis motion system. The user manually controls the multi-axis motion system to move the vision camera to perform point matching on the mark block on the calibration board at different spatial poses. The preset number of different poses is a different shooting pose set by the user, and the preset number can be set according to actual conditions. Different shooting poses can also be selected according to actual conditions, such as the 19 combinations shown in Table 1, that is, the point matching conditions formed by different mark blocks and different shooting poses.

[0080] Table 1

[0081] Serial number X Y A C Serial number X Y A C 1 20 20 0 0 11 20 20 10 60 2 20 20 0 60 12 20 20 25 120 3 20 20 0 120 13 20 20 20 180 4 20 20 0 180 14 20 20 -10 240 5 20 20 0 240 15 20 20 -20 300 6 20 20 0 300 16 20 20 -25 0 7 20 20 5 0 17 50 50 0 0 8 20 20 -5 0 18 50 -50 0 0 9 20 20 15 0 19 -50 50 0 0 10 20 20 -15 0

[0082] In the above table 1, X and Y represent the coordinate values of the mark block on the calibration board in the calibration coordinate system, and A and C represent the shooting poses of the vision camera, A represents the inclination angle, and C represents the rotation angle. In actual application, there can be more or less different point matching conditions than in Table 1.

[0083] In this embodiment, the point matching operation can be performed for each group of point matching conditions formed by the coordinate values of the mark block and the angle values of the shooting pose. That is, the vision camera is manually controlled to perform point matching on the mark block on the calibration board at the above-mentioned poses, so that the vision intersection point and the center point of the mark block coincide.

[0084] Step S130: When the vision intersection point of the vision camera coincides with the center point of the mark block, record the first coordinate pair formed by the mechanical coordinate system coordinates of the multi-axis motion system and the coordinates of the mark block on the calibration coordinate system of the calibration board.

[0085] Specifically, when the vision camera is controlled to perform point matching on the mark block on the calibration board at different poses according to the above table 1, and the vision intersection point and the center point of the mark block coincide, the mechanical coordinate system coordinates of the multi-axis motion system and the coordinates of the mark block on the calibration coordinate system at this time can be recorded. According to the recorded coordinate data, a corresponding point, that is, a first coordinate pair, is formed. According to the above table 1, 19 first coordinate pairs can be obtained.

[0086] Step S140: According to the preset number of first coordinate pairs, the initial correspondence relationship between the mechanical coordinate system of the multi-axis motion system and the calibration coordinate system of the calibration board is obtained by a spatial geometric algorithm.

[0087] Specifically, the step S130 obtains a preset number of first coordinate pairs, here 19 groups of first coordinate pairs, and solves the relative relationship between the mechanical coordinate system and the calibration coordinate system, i.e., the initial correspondence relationship, so that the coordinates of any mark block on the calibration plate in any shooting posture in the mechanical coordinate system of the multi-axis motion system can be obtained, and the coordinate values of the mark block in the mechanical coordinate system of each axis of the multi-axis motion system can also be obtained.

[0088] The step S200: determining a target calibration point corresponding on the mechanical coordinate system based on the initial correspondence relationship, the target collection points of the calibration plate and the target pose of the vision camera.

[0089] In order to obtain the accurate relative relationship between the mechanical coordinate system and the calibration coordinate system, more groups of corresponding points composed of the mechanical coordinate system coordinates of the multi-axis motion system and the calibration coordinate system coordinates of the calibration plate with more comprehensive shooting postures need to be obtained, therefore, the number of target calibration points can be much larger than the preset number, so as to obtain a large amount of coordinate data of the corresponding points.

[0090] In an embodiment, the step S200 can include:

[0091] The step S210: determining the target pose of the vision camera, the two-dimensional collection points in the preset area on the calibration plate and the three-dimensional collection points relative to the calibration plate, wherein the target pose includes a plurality of poses uniformly distributed at equal angles.

[0092] Specifically, the target pose of the vision camera can be a user-defined number of different shooting postures. These shooting postures can be uniformly distributed in the three-dimensional space near the plane of the calibration plate. Taking a five-axis machine tool with A and C double-turntable cradle structure as an example, assuming that the pose of the vision camera can be adjusted by rotating the angles of the A and C axes, the angle range of the A axis rotation can be determined according to the maximum flip angle of the calibration block on the calibration plate that can be recognized by the vision camera; generally, when the workbench is horizontal, the angle of the A axis is zero, so the limit of the positive and negative directions of the A axis is the maximum flip angle of the calibration block on the calibration plate that can be recognized by the vision camera; the angles of the A axis can be selected at equal intervals within the above angle range, such as the shooting posture angles of serial numbers 1-6 in Table 1; similarly, the angles of the C axis can also be selected at equal intervals within the range of the maximum flip angle of the calibration block on the calibration plate that can be recognized by the vision camera without interference, so that more shooting postures can be obtained by arbitrarily and freely combining the selected angles of the A and C axes, so that the vision camera can be automatically positioned in these different shooting postures in the subsequent process, i.e., the target pose of the vision camera is obtained. Designing multiple different poses can make the calibration method more universal and more accurate.

[0093] The two-dimensional acquisition points in the preset region on the calibration board and the three-dimensional acquisition points relative to the calibration board are determined to determine the target acquisition points based on the calibration board. The two-dimensional acquisition points are for the subsequent automatic calibration, and the visual intersection point of the visual camera can be located on the plane of the calibration board. The three-dimensional acquisition points are for the subsequent automatic calibration, and the visual intersection point of the visual camera can be located in the three-dimensional space away from the plane of the calibration board. It should be noted that the steps of determining the target pose of the visual camera and the steps of determining the two-dimensional acquisition points in the preset region on the calibration board and the three-dimensional acquisition points relative to the calibration board can be performed independently or in sequence, and the specific method is determined according to the actual situation.

[0094] In the embodiment, the step S210 of determining the two-dimensional acquisition points in the preset region on the calibration board can include:

[0095] Step S211: determining N acquisition points of a first quadrant in the calibration coordinate system in the preset region of the calibration board, N≥1, wherein the first quadrant is any quadrant of the calibration coordinate system;

[0096] Step S212: determining N acquisition points of a second quadrant and N acquisition points of a fourth quadrant of the N acquisition points about any coordinate axis of the calibration coordinate system, and N acquisition points of a third quadrant of the N acquisition points of the second quadrant or the N acquisition points of the fourth quadrant about any coordinate axis of the calibration coordinate system;

[0097] Step S213: obtaining 4N+1 two-dimensional acquisition points according to the N acquisition points of the first quadrant, the N acquisition points of the second quadrant, the N acquisition points of the third quadrant, the N acquisition points of the fourth quadrant, and the coordinate origin of the calibration coordinate system.

[0098] Specifically, hundreds of two-dimensional acquisition points on the plane of the calibration board can be designed to convert the corresponding target calibration points for each target acquisition point in the subsequent process, so as to obtain a large number of target calibration points. In order to make the calibration method more universal, the two-dimensional acquisition points should cover as many positions on the calibration board as possible. Due to the influence of assembly, the flatness of the edge region of the calibration board is generally slightly lower, so the mark blocks on the edge of the calibration board can be ignored. That is, the preset region can be the central region or other regions excluding the edge region of the calibration board set by the user, and can be a rectangle, a square, or a circle, etc. Then, based on the calibration coordinate system of the calibration board, any one quadrant is selected as the first quadrant. Assuming that the first quadrant is the first quadrant of the calibration coordinate system in the true sense, the corresponding other quadrants are defined according to the four-quadrant relationship of the coordinate system. It should be noted that since the position of the calibration board is not fixed, but the calibration coordinate system is generally fixed, the first quadrant can also be other quadrants of the calibration coordinate system, which will not be described here.

[0099] Correspondingly, in the preset region of the calibration board, N acquisition points are determined in the first quadrant thereof. In order to make the calibration method more accurate, the N acquisition points can be determined as much as possible, but generally will not exceed the number of calibration blocks that can be selected in the quadrant. The acquisition point refers to the center point of the calibration block. Alternatively, the number of acquisition points can be appropriately reduced in consideration of efficiency, and therefore the number of acquisition points can be set according to actual conditions. Assuming that in the first quadrant of the preset region, the inside region, the middle region and the outside region, and the edge region can be divided in the outward direction from the origin, the N acquisition points determined here can be mainly concentrated in the middle region and the outside region in the quadrant region, and the calibration blocks on the edge region are not used. In this way, the N acquisition points distributed in the first quadrant can be obtained.

[0100] Then, based on the N acquisition points in the first quadrant, the N acquisition points in the corresponding second quadrant can be obtained by symmetry with respect to the Y axis of the calibration coordinate system, and the N acquisition points in the corresponding fourth quadrant can be obtained by symmetry with respect to the X axis of the calibration coordinate system. Then, the N acquisition points in the corresponding third quadrant can be obtained by symmetry with respect to the Y axis with respect to the N acquisition points in the second quadrant, or the same N acquisition points in the third quadrant can be obtained by symmetry with respect to the Y axis with respect to the N acquisition points in the fourth quadrant. In this way, there are N acquisition points in each quadrant, and 4N acquisition points can be obtained in the preset region of the calibration board. The zero point, i.e. the coordinate origin, can also be added, so that 4N+1 two-dimensional acquisition points can be obtained.

[0101] The 4N+1 two-dimensional acquisition points are distributed symmetrically, not only locally symmetrically, but also globally symmetrically, and the smoothing effect is better. The influence of the error of the acquisition data on the calibration method can be reduced, and the accuracy of the calibration method can be improved.

[0102] In the specific implementation, determining the three-dimensional acquisition point relative to the calibration board in step S210 can include:

[0103] Step S214: determining M initial acquisition points on the calibration board and an arbitrary pose of the vision camera, M≥1 and M<4N+1;

[0104] Step S215: for each initial acquisition point, controlling the vision camera to perform a point operation in the arbitrary pose;

[0105] Step S216: when the visual intersection point of the vision camera coincides with the initial acquisition point, moving the initial acquisition point by a preset distance in a three-dimensional direction perpendicular to the calibration board to obtain M three-dimensional acquisition points, wherein the preset distance is set based on the visibility of the initial acquisition point in the visual range of the vision camera.

[0106] Specifically, to make the error compensation result more accurate, a small number of three-dimensional collection points compared with two-dimensional collection points can be added to obtain the position data of the visual intersection point away from the plane of the calibration board. The specific determination process of the three-dimensional collection point is as follows: first, an initial collection point is determined on the plane of the calibration board, that is, the visual intersection point coincides with the point under any pose of the visual camera, and then the Z axis in the three-dimensional space, that is, the axis perpendicular to the plane of the calibration board, is controlled to move a proper distance, and the proper distance is selected as a standard so that the visual camera can recognize the point. At this time, a three-dimensional collection point away from the plane of the calibration board is obtained, and the above operation is repeated to obtain M three-dimensional collection points. M < 4N + 1 means that the number of three-dimensional collection points is less than the number of two-dimensional collection points. In combination with the aforementioned two-dimensional collection points, the number of two-dimensional collection points should be as large as possible, and the number of three-dimensional collection points can be small because the three-dimensional collection points are only used to make the calibration more accurate. If too many three-dimensional collection points are set, the calibration efficiency will be reduced. Therefore, the automatic calibration is mainly performed by using two-dimensional collection points. According to the above process, the initial collection point is selected in the range of the calibration board, and a small number of three-dimensional collection points, for example, 3-5, are determined in the range in which the visual camera can recognize the initial collection point under any shooting pose. Meanwhile, according to the above steps S21-213, a plurality of two-dimensional collection points, for example, 5-10, can be selected. It can be understood that the specific number can be set according to actual needs.

[0107] Step S220: obtaining target collection points based on the calibration board according to the two-dimensional collection points and the three-dimensional collection points.

[0108] The 4N + 1 two-dimensional collection points and the M three-dimensional collection points obtained above constitute the target collection points.

[0109] Step S230: converting the target collection points into coordinates on the mechanical coordinate system under the target pose according to the initial correspondence relationship to obtain the target calibration points.

[0110] In the specific implementation, step S230 can include:

[0111] Step S231: determining the coordinates of the target collection points on the mechanical coordinate system under the target pose according to the initial correspondence relationship.

[0112] Step S232: converting the coordinates of the target collection points on the mechanical coordinate system to obtain the coordinate values on the mechanical coordinate systems of each axis in the multi-axis motion system to obtain the target calibration points.

[0113] According to the initial correspondence relationship obtained in step S100, coordinates of the target acquisition points corresponding to different target poses in the mechanical coordinate system of the multi-axis motion system are determined. The coordinates are comprehensive values and have not been specifically determined in the mechanical coordinate systems of the axes of the multi-axis motion system. Therefore, conversion can be performed to obtain coordinate values corresponding to the mechanical coordinate systems of the axes of the multi-axis motion system. The coordinate value information is the information of the target calibration points, and the target calibration points are obtained.

[0114] It should be noted that the different target poses and the plurality of target acquisition points can be combined arbitrarily. Therefore, a plurality of target calibration points can be obtained. The target calibration points are only a few millimeters away from the accurate point in terms of geometric error. In this case, an automatic point matching process can be performed by the vision camera to eliminate the geometric error to a greater extent. That is, the plurality of target calibration points obtained can be freely combined with the plurality of target poses obtained above to obtain a large number of different combinations, so that automatic calibration is performed multiple times to obtain more groups of coordinate pairs, and the relative relationship between the mechanical coordinate system and the calibration coordinate system is accurately calculated.

[0115] Step S300: generating an automatic calibration instruction according to the target calibration point.

[0116] Specifically, during automatic calibration, the host computer can issue an instruction. That is, after the host computer receives the target calibration point and the coordinate data based on the mechanical coordinate systems of the axes of the multi-axis motion system from the control device, the host computer generates an automatic calibration instruction based on the automatic calibration software of the host computer, and issues the automatic calibration instruction to the control device. Then, the second target calibration point is obtained, and the automatic calibration instruction corresponding to the second target calibration point is generated and issued. This process is repeated until all target calibration points are calibrated. Alternatively, after the control device itself obtains a target calibration point and its coordinate data by performing the above steps, the control device directly generates an automatic calibration instruction based on the current target calibration point, and performs an automatic calibration operation. Then, the second target calibration point and its coordinate data are obtained, and the automatic calibration instruction corresponding to the second target calibration point is generated. This process is repeated until all target calibration points are obtained and the last target calibration point is calibrated. The specific implementation can be selected according to the actual situation. When the user selects the host computer to issue the automatic calibration instruction, step S300 can be replaced with sending the target calibration point to the host computer and receiving the automatic calibration instruction sent by the host computer.

[0117] Step S400: According to the automatic calibration instruction, the vision camera controls the target calibration point to perform a point matching operation to obtain the final correspondence relationship between the mechanical coordinate system and the calibration coordinate system.

[0118] Specifically, for multiple target calibration points, the automatic calibration operation is sequentially performed until all target calibration points are automatically calibrated, and the entire geometric error calibration method is completed.

[0119] In an embodiment, the step S400 can include:

[0120] Step S410: According to the automatic calibration instruction, the target calibration point is controlled by the visual camera in the target pose to perform the point matching operation.

[0121] Specifically, in the automatic calibration instruction, the coordinate data given by the target calibration point is the coordinate of each axis mechanical coordinate system of the multi-axis motion system, the control device controls the multi-axis motion system to move to the position according to the coordinate data, and then controls the visual camera to perform the point matching operation on the target acquisition point corresponding to the target calibration point on the calibration plate, i.e. the aforementioned target acquisition point, in different target poses, so that the visual center of the visual camera coincides with the target acquisition point. At this time, the visual center also coincides with the target calibration point.

[0122] Step S420: When the visual intersection of the visual camera coincides with the target calibration point, a second coordinate pair composed of the mechanical coordinate system coordinate of the multi-axis motion system and the coordinate of the target calibration point on the calibration coordinate system is recorded.

[0123] Specifically, when the visual center of the visual camera coincides with the target calibration point, the mechanical coordinate system coordinate data of the multi-axis motion system and the coordinate of the target calibration point on the calibration coordinate system, i.e. the coordinate data of the target acquisition point, are recorded. The coordinate data forms a corresponding point, i.e. a second coordinate pair.

[0124] Step S430: According to the second coordinate pair, the final corresponding relationship between the mechanical coordinate system and the calibration coordinate system is obtained through a spatial geometric algorithm.

[0125] Specifically, the above steps are repeated, and after automatic calibration is performed on all target calibration points, multiple second coordinate pairs are obtained, and the final corresponding relationship between the mechanical coordinate system and the calibration coordinate system is obtained through a spatial geometric algorithm. The relative relationship between the mechanical coordinate system of the multi-axis motion system and the standard space coordinate system is obtained, and the geometric error calibration of the multi-axis motion system is completed.

[0126] After that, according to the above final corresponding relationship, the actual kinematic relationship of the multi-axis motion system can be solved based on the standard space coordinate system as a reference. In actual space positioning, the original instruction coordinate value is converted into the actual coordinate value on the mechanical coordinate system of each axis of the multi-axis motion system according to the actual kinematic relationship, to realize high-precision space positioning capability.

[0127] The geometric error calibration method of the universal multi-axis motion system provided by the embodiment can automatically, quickly and accurately calibrate a plurality of sets of coordinate pair data of a mechanical coordinate system of the multi-axis motion system and a calibration coordinate system of a calibration plate serving as a standard space coordinate system, so that the actual kinematic relationship of the multi-axis motion system can be solved based on the standard space coordinate system, and the usability of a subsequent geometric error compensation scheme of the multi-axis motion system can be improved. The method solves the problems of complicated operation process, easy errors and long time consumption in the existing manual calibration process, avoids human errors, saves 20 times of time, and completes the calibration of the multi-axis motion system within 1 hour, thereby improving the calibration efficiency.

[0128] Embodiment Two

[0129] Based on the same inventive concept, referring to Figure 3 , the first embodiment of the geometric error calibration device is provided, which can be a virtual device and is applied to the multi-axis motion system.

[0130] The geometric error calibration device provided by the embodiment will be described in detail below with reference to the functional module schematic diagram shown in Figure 3 . The device can include:

[0131] An initial calibration module is configured to perform manual calibration according to a user operation instruction to obtain an initial corresponding relationship between a mechanical coordinate system of the multi-axis motion system and a calibration coordinate system of the calibration plate.

[0132] A target determination module is configured to determine a target calibration point corresponding on the mechanical coordinate system based on a target collection point of the calibration plate and a target pose of the vision camera according to the initial corresponding relationship.

[0133] An instruction generation module is configured to generate an automatic calibration instruction according to the target calibration point.

[0134] An automatic calibration module is configured to control the vision camera to perform a point matching operation on the target calibration point according to the automatic calibration instruction to obtain a final corresponding relationship between the mechanical coordinate system and the calibration coordinate system.

[0135] Further, the initial calibration module can include:

[0136] A first acquisition unit is configured to acquire a user operation instruction.

[0137] A first point matching unit is configured to control the vision camera to perform a point matching operation on the mark block on the calibration plate in a preset number of different poses according to the user operation instruction.

[0138] a first recording unit, configured to record a first coordinate pair composed of a coordinate of a mechanical coordinate system of the multi-axis motion system and a coordinate of the marker block on a calibration coordinate system of the calibration plate when a visual intersection of the visual camera coincides with a center point of the marker block;

[0139] a first calculating unit, configured to obtain an initial correspondence relationship between the mechanical coordinate system of the multi-axis motion system and the calibration coordinate system of the calibration plate by a spatial geometric algorithm according to the first coordinate pairs of the preset quantity.

[0140] Further, the target determining module can comprise:

[0141] a data determining unit, configured to determine a target pose of the visual camera, two-dimensional acquisition points in a preset region on the calibration plate and three-dimensional acquisition points relative to the calibration plate, wherein the target pose comprises a plurality of poses uniformly distributed at equal angles;

[0142] an acquisition point determining unit, configured to obtain target acquisition points based on the calibration plate according to the two-dimensional acquisition points and the three-dimensional acquisition points;

[0143] a target determining unit, configured to convert the target acquisition points into coordinates on the mechanical coordinate system at the target pose according to the initial correspondence relationship, to obtain the target calibration points.

[0144] Still further, the data determining unit is further configured to determine N acquisition points of a first quadrant in the preset region of the calibration plate, N≥1, wherein the first quadrant is any quadrant of the calibration coordinate system; determine N acquisition points of a second quadrant and N acquisition points of a fourth quadrant symmetrical about any coordinate axis of the calibration coordinate system with respect to the N acquisition points of the first quadrant, and N acquisition points of a third quadrant symmetrical about any coordinate axis of the calibration coordinate system with respect to the N acquisition points of the second quadrant or the N acquisition points of the fourth quadrant; and obtain 4N+1 two-dimensional acquisition points according to the N acquisition points of the first quadrant, the N acquisition points of the second quadrant, the N acquisition points of the third quadrant, the N acquisition points of the fourth quadrant and a coordinate origin of the calibration coordinate system.

[0145] Still further, the data determining unit is further configured to determine M initial acquisition points on the calibration plate and any pose of the visual camera, M≥1 and M<4N+1; control the visual camera to perform a point operation at the any pose for each initial acquisition point; when a visual intersection of the visual camera coincides with the initial acquisition point, move the initial acquisition point by a preset distance along a three-dimensional direction perpendicular to the calibration plate to obtain M three-dimensional acquisition points, wherein the preset distance is set based on that the initial acquisition point is visible within a visual range of the visual camera.

[0146] Further, the target determining unit is further configured to determine, according to the initial correspondence relationship, coordinates of the target collection point corresponding to the mechanical coordinate system in the target pose; and convert the coordinates of the target collection point corresponding to the mechanical coordinate system in the target pose to obtain coordinate values corresponding to the mechanical coordinate system of each axis in the multi-axis motion system, to obtain the target calibration point.

[0147] Further, the automatic calibration module can comprise:

[0148] A second point matching unit configured to control the vision camera to perform a point matching operation on the target calibration point in the target pose according to the automatic calibration instruction;

[0149] A second recording unit configured to record a second coordinate pair composed of the mechanical coordinate system coordinate of the multi-axis motion system and the coordinate of the target calibration point in the calibration coordinate system when the visual intersection of the vision camera coincides with the target calibration point;

[0150] A second calculating unit configured to obtain a final correspondence relationship between the mechanical coordinate system and the calibration coordinate system by a spatial geometric algorithm according to the second coordinate pair.

[0151] It should be noted that the functions and technical effects achieved by each module of the geometric error calibration device provided in the embodiment can be referred to the description of the geometric error calibration method embodiments of the present application, and will not be repeated here for the sake of brevity of the description.

[0152] Embodiment Three

[0153] Based on the same inventive concept, referring to the hardware structure diagram of Figure 2 , the embodiment provides a multi-axis motion system, which can comprise:

[0154] a work component, a workbench and a control device. The work component is provided with a vision camera; the workbench is provided with a calibration board; and the control device is a control device that comprehensively controls the hardware and software structure of the whole system around complex motion, which can be a terminal device such as an embedded industrial computer, or a device such as a controller and a processor.

[0155] As shown in Figure 2 , it is a hardware structure diagram of the control device. The control device can comprise a processor and a memory, and the memory stores a geometric error calibration program. When the geometric error calibration program is executed by the processor, all or part of the steps of each embodiment of the geometric error calibration method of the present application are realized.

[0156] It can be understood that the multi-axis motion system can further include a communication bus, a user interface and a network interface. Among them, the communication bus is used to realize the connection communication between the components; the user interface is used to connect the client and communicate data with the client, and the user interface can include an output unit such as a display screen and an input unit such as a keyboard; the network interface is used to connect the background server and communicate data with the background server, and the network interface can include an input / output interface, such as a standard wired interface, a wireless interface.

[0157] The memory is used to store various types of data, which can include, for example, instructions of any application program or method in the control device, and application-related data. The memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk. Optionally, the memory can also be a storage device independent of the processor.

[0158] The processor is used to call the geometric error calibration program stored in the memory and execute the geometric error calibration method as described above. The processor can be an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a controller, a microcontroller, a microprocessor or other electronic elements, and is used to execute all or part of the steps of each embodiment of the geometric error calibration method as described above.

[0159] Embodiment four

[0160] Based on the same inventive concept, the embodiment provides a computer readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card memory (for example, an SD or DX memory, etc.), a random access memory (RAM), a static random access memory (SRAM), a read only memory (ROM), a programmable read only memory (PROM), an erasable programmable read only memory (EPROM), an electrically erasable programmable read only memory (EEPROM), a magnetic memory, a magnetic disk, an optical disk, a server, and the like, which stores a computer program. The computer program can be executed by one or more processors. When the computer program is executed by the processor, all or part of the steps of the embodiments of the inventive geometric error calibration method can be implemented.

[0161] It should be noted that the above-mentioned embodiment numbers of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments. The above embodiments are only optional embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent flow transformation made by using the content of the present application specification and drawings, or directly or indirectly applied to other related technical fields under the inventive concept of the present application, is included in the patent protection scope of the present application.

Claims

1. A geometric error calibration method, characterized in that, The method is used for a multi-axis motion system including a work component and a workbench, the work component is provided with a visual camera, and the workbench is provided with a calibration board, and the method comprises: manual calibration according to a user operation instruction to obtain an initial corresponding relationship between a mechanical coordinate system of the multi-axis motion system and a calibration coordinate system of the calibration board; determination of a corresponding target calibration point on the mechanical coordinate system according to the initial corresponding relationship, a target collection point based on the calibration board and a target pose of the visual camera; generation of an automatic calibration instruction according to the target calibration point; control of the visual camera to perform a point matching operation on the target calibration point according to the automatic calibration instruction to obtain a final corresponding relationship between the mechanical coordinate system and the calibration coordinate system; the determination of the corresponding target calibration point on the mechanical coordinate system according to the initial corresponding relationship, the target collection point based on the calibration board and the target pose of the visual camera comprises: determination of the target pose of the visual camera, two-dimensional collection points in a preset region on the calibration board and three-dimensional collection points relative to the calibration board, wherein the target pose comprises a plurality of poses uniformly distributed at equal angles; obtaining of the target collection point based on the calibration board according to the two-dimensional collection points and the three-dimensional collection points; conversion of the target collection point into a coordinate on the mechanical coordinate system under the target pose according to the initial corresponding relationship to obtain the target calibration point.

2. The geometric error calibration method of claim 1, wherein, the manual calibration according to the user operation instruction to obtain the initial corresponding relationship between the mechanical coordinate system of the multi-axis motion system and the calibration coordinate system of the calibration board comprises: acquisition of a user operation instruction; control of the visual camera to perform a point matching operation on a mark block on the calibration board in a preset number of different poses according to the user operation instruction; recording of a first coordinate pair composed of a mechanical coordinate system coordinate of the multi-axis motion system and a coordinate of the mark block on the calibration coordinate system of the calibration board when a visual intersection point of the visual camera coincides with a center point of the mark block; obtaining of the initial corresponding relationship between the mechanical coordinate system of the multi-axis motion system and the calibration coordinate system of the calibration board through a spatial geometric algorithm according to the preset number of the first coordinate pairs.

3. The geometric error calibration method of claim 1, wherein, the determination of the two-dimensional collection points in the preset region on the calibration board comprises: determination of N collection points in a first quadrant of the calibration coordinate system in a preset region of the calibration board, N≥1, wherein the first quadrant is any quadrant of the calibration coordinate system; determination of N collection points in a second quadrant and N collection points in a fourth quadrant of the N collection points symmetrical about any coordinate axis of the calibration coordinate system, and N collection points in a third quadrant symmetrical about any coordinate axis of the calibration coordinate system of the N collection points in the second quadrant or the N collection points in the fourth quadrant; obtaining of 4N+1 two-dimensional collection points according to the N collection points in the first quadrant, the N collection points in the second quadrant, the N collection points in the third quadrant, the N collection points in the fourth quadrant and a coordinate origin of the calibration coordinate system.

4. The geometric error calibration method of claim 3, wherein, The determining of the three-dimensional acquisition points relative to the calibration board comprises: determining M initial acquisition points on the calibration board and an arbitrary pose of the vision camera, M≥1 and M<4N+1; for each initial acquisition point, controlling the vision camera to perform a point operation in the arbitrary pose; when the visual intersection point of the vision camera coincides with the initial acquisition point, moving the initial acquisition point by a preset distance in a three-dimensional direction perpendicular to the calibration board to obtain M three-dimensional acquisition points, wherein the preset distance is set based on the visibility of the initial acquisition point in the visual range of the vision camera.

5. The geometric error calibration method of claim 1, wherein, The converting of the target acquisition point into a coordinate on the mechanical coordinate system under the target pose according to the initial correspondence relationship to obtain the target calibration point comprises: determining, according to the initial correspondence relationship, a coordinate corresponding to the target acquisition point on the mechanical coordinate system under the target pose; converting the coordinate corresponding to the target acquisition point on the mechanical coordinate system to obtain coordinate values corresponding to the mechanical coordinate system of each axis in the multi-axis motion system to obtain the target calibration point.

6. The geometric error calibration method of claim 1, wherein, The controlling of the vision camera to perform a point operation on the target calibration point according to the automatic calibration instruction to obtain the final correspondence relationship between the mechanical coordinate system and the calibration coordinate system comprises: controlling the vision camera to perform a point operation on the target calibration point in the target pose according to the automatic calibration instruction; when the visual intersection point of the vision camera coincides with the target calibration point, recording a second coordinate pair composed of the mechanical coordinate system coordinate of the multi-axis motion system and the coordinate of the target calibration point on the calibration coordinate system; obtaining the final correspondence relationship between the mechanical coordinate system and the calibration coordinate system through a spatial geometric algorithm according to the second coordinate pair.

7. A geometric error calibration device, characterized by, The device is used in a multi-axis motion system, the multi-axis motion system comprising a work component and a workbench, the work component being provided with a vision camera, and the workbench being provided with a calibration board, and the device comprising: an initial calibration module configured to perform manual calibration according to a user operation instruction to obtain an initial correspondence relationship between a mechanical coordinate system of the multi-axis motion system and a calibration coordinate system of the calibration board; a target determination module configured to determine a target calibration point corresponding on the mechanical coordinate system according to the initial correspondence relationship, based on a target acquisition point of the calibration board and a target pose of the vision camera; an instruction generation module configured to generate an automatic calibration instruction according to the target calibration point; an automatic calibration module configured to control the vision camera to perform a point operation on the target calibration point according to the automatic calibration instruction to obtain a final correspondence relationship between the mechanical coordinate system and the calibration coordinate system; the target determination module comprising: a data determination unit configured to determine the target pose of the vision camera, two-dimensional acquisition points in a preset region on the calibration board, and three-dimensional acquisition points relative to the calibration board, wherein the target pose comprises a plurality of poses uniformly distributed at equal angles. The acquisition point determination unit is configured to obtain target acquisition points based on the calibration plate according to the two-dimensional acquisition points and the three-dimensional acquisition points. The target determination unit is configured to convert the target acquisition points into coordinates in the mechanical coordinate system under the target pose according to the initial correspondence relationship, to obtain the target calibration points.

8. A multi-axis motion system characterized by, The system comprises: a work component, wherein a vision camera is arranged on the work component; a workbench, wherein a calibration plate is arranged on the workbench; a control device, wherein the control device comprises a processor and a memory, and the memory stores a geometric error calibration program, and the geometric error calibration program is executed by the processor to implement the geometric error calibration method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, and the computer program is executed by one or more processors to implement the geometric error calibration method according to any one of claims 1 to 6.

Images