Five-axis equipment platform, calibration method thereof and storage medium

Abstract

The invention discloses a five-axis equipment platform, a calibration method thereof and a storage medium. The method comprises the following steps: adjusting a carrying table of the five-axis equipment platform to enable a calibration plate on the carrying table to be in a horizontal state, and obtaining a first calibration data point of a linear motion axis; driving a first rotating shaft of the five-axis equipment platform to rotate for a set number of times, and acquiring a first space coordinate group when the center of the calibration plate coincides with the camera view center of the five-axis equipment platform after each rotation; calibrating the first rotating shaft according to the first calibration data point and the first space coordinate group; driving a second rotating shaft of the five-axis equipment platform to rotate for a set number of times, and acquiring a second space coordinate group when the distance of the set position of the calibration plate is a preset measurement distance after each rotation; and calibrating the second rotating shaft according to the first calibration data point and the second space coordinate group. The calibration method is simple and efficient, and the calibration precision can be ensured.

Description

Technical Field

[0001] The present invention relates to the field of image data processing, and in particular, to a five-axis equipment platform, a calibration method thereof, and a storage medium. Background Art

[0002] The five-axis equipment platform is an advanced industrial robot or automation equipment technology, and has become an important tool in modern manufacturing with its complex motion control ability and strong adaptability.

[0003] Please refer to Figure 1 in Figure 1 a and Figure 1 b. The dual turntable five-axis equipment corresponds to the traditional X-axis, Y-axis, and Z-axis. On the basis of these three axes, a corresponding "parallel" rotation relationship is established. The X-axis, Y-axis, and Z-axis respectively correspond to the A-axis, B-axis, and C-axis. The axis rotating around the X-axis is the A-axis, the axis rotating around the Y-axis is the B-axis, and the axis rotating around the Z-axis is the C-axis. The five-axis equipment realizes linear motion through the three coordinates of the X-axis, Y-axis, and Z-axis. The A-axis (or B-axis) and C-axis are respectively responsible for elevation angle adjustment and rotation, so that complex three-dimensional motion trajectories can be completed. This precise motion control enables the five-axis equipment to perform excellently in high-precision manufacturing. The five-axis equipment can move freely in a large space, adapt to a variety of complex working environments, and at the same time maintain a high positioning accuracy, and can be applied to fields such as drilling, cutting, assembly, welding, dispensing, and curved surface product inspection.

[0004] Compared with the three-axis platform, the dual turntable five-axis equipment platform adds two rotating axes, and the mechanical structure becomes more complex. Due to the installation errors existing in the assembly process of the mechanical structure and the wear caused by long-term operation of the machine, it is necessary to calibrate the five-axis equipment regularly, that is, to calibrate the spatial vectors of the two rotating axis centerlines in the platform mechanical coordinates respectively.

[0005] Generally, a ball bar, a camera and a laser rangefinder, or a standard ball and a micrometer can be used for the calibration of the five-axis equipment platform. No matter which method is used to calibrate the five-axis equipment platform, the calibration process is relatively troublesome, with low efficiency and high professional requirements. Summary of the Invention

[0006] The main technical problem to be solved by the present invention is: to provide a more convenient five-axis equipment platform and its corresponding calibration method.

[0007] According to a first aspect, in one embodiment, a calibration method for a five-axis equipment platform is provided, including: Adjust the carrier of the five-axis equipment platform to make the calibration plate on the carrier in a horizontal state, and obtain the first calibration data points of the linear motion axis; Drive the first rotating shaft of the five-axis equipment platform to rotate a set number of times, and obtain a first set of spatial coordinates when the center of the calibration plate coincides with the camera field of view center of the five-axis equipment platform after each rotation; Calibrate the first rotating shaft according to the first calibration data points and the first set of spatial coordinates; Drive the second rotating shaft of the five-axis equipment platform to rotate a set number of times, and obtain a second set of spatial coordinates when the distance at a set position of the calibration plate is a preset measurement distance after each rotation; Calibrate the second rotating shaft according to the first calibration data points and the second set of spatial coordinates.

[0008] In one embodiment, adjusting the stage of the five-axis equipment platform to make the calibration plate on the stage in a horizontal state includes: Drive the first rotating shaft and the linear motion shaft to make the calibration plate in the camera field of view, where the calibration plate includes a first feature point, a second feature point, a third feature point, and a fourth feature point; In the camera field of view, obtain a first center distance between the first feature point and the second feature point; In the camera field of view, obtain a second center distance between the third feature point and the fourth feature point; Drive the second rotating shaft and the linear motion shaft until the first center distance and the second center distance are equal.

[0009] In one embodiment, the first feature point and the second feature point are located at the top of the calibration plate; the third feature point and the fourth feature point are located at the bottom of the calibration plate; the actual distance between the first feature point and the second feature point is equal to the actual distance between the third feature point and the fourth feature point.

[0010] In one embodiment, the driving the first rotating shaft of the five-axis equipment platform to rotate a set number of times and obtaining a first set of spatial coordinates when the center of the calibration plate coincides with the camera field of view center of the five-axis equipment platform after each rotation includes: Drive the first rotating shaft of the five-axis equipment platform to rotate a set number of times and at a first set angle; After each rotation of the first rotating shaft, move the linear motion shaft of the five-axis equipment platform to make the center of the calibration plate coincide with the camera field of view center of the five-axis equipment platform; Each time the center of the calibration plate coincides with the camera field of view center of the five-axis equipment platform, the coordinates of the linear motion shaft form the first set of spatial coordinates.

[0011] In one embodiment, driving the second rotating shaft of the five-axis equipment platform to rotate a set number of times, and obtaining a second set of spatial coordinates when the distance at the set position of the calibration plate after each rotation is a preset measurement distance, includes: When the calibration plate is in a horizontal state, driving the second rotating shaft of the five-axis equipment platform to rotate a set number of times and a second set angle; After each rotation of the second rotating shaft, moving the linear motion axis of the five-axis equipment platform so that the distance at the set position of the calibration plate is a preset measurement distance. When the distance at the set position of the calibration plate is a preset measurement distance each time, the coordinates of the linear motion axis form the second set of spatial coordinates.

[0012] In one embodiment, the set position of the calibration plate is the middle area where the center of the calibration plate is located; the calibration plate further includes a fifth feature point and a sixth feature point distributed in the middle area, and the preset measurement distance is the distance between the fifth feature point and the sixth feature point at the center of the camera's field of view when the calibration plate is in a horizontal state.

[0013] In one embodiment, the range of the first set angle is 5° to 100°; or, the range of the second set angle is 5° to 30°.

[0014] In one embodiment, calibrating the first rotating shaft according to the first calibration data points and the first set of spatial coordinates includes: Performing a cross product on the first calibration data points and the first set of spatial coordinates to determine the spatial vector of the axis line of the first rotating shaft; Or, Calibrating the second rotating shaft according to the first calibration data points and the second set of spatial coordinates includes: Performing a cross product on the first calibration data points and the second set of spatial coordinates to determine the spatial vector of the axis line of the second rotating shaft.

[0015] According to a second aspect, in one embodiment, a five-axis equipment platform is provided, including: A linear motion module, including linear motion axes that move in the X-axis, Y-axis, and Z-axis directions perpendicular to each other; A rotational motion module, including a first rotating shaft and a second rotating shaft, the rotation axis of the first rotating shaft being perpendicular to the rotation axis of the second rotating shaft; A control module, using the calibration method of the five-axis equipment platform described in any of the above embodiments to calibrate the first rotating shaft and the second rotating shaft.

[0016] According to a third aspect, in one embodiment, a computer-readable storage medium is provided, on which a computer program is stored, and the computer program can be executed by a processor to implement the method described in any of the above embodiments.

[0017] For the five-axis device platform and its calibration method, computer program product, and storage medium according to the above embodiments, in this calibration method, the calibration plate on the carrier is adjusted to be in a horizontal state. After the calibration plate is in a horizontal state, the first calibration data points and the first spatial coordinate group of the first rotating shaft, as well as the second spatial coordinate group, are respectively obtained. The first rotating shaft is calibrated according to the first calibration data points and the first spatial coordinate group. At the same time, the second rotating shaft is calibrated according to the first calibration data points and the second spatial coordinate group. In this application, by collecting the spatial point coordinate data required for calibrating two rotating shafts of the five-axis device platform, the calibration of the spatial vectors of the two rotating shafts in the platform coordinate system is realized. In the calibration process of this application, it is not necessary to use a laser rangefinder or other high-precision devices, which reduces the calibration cost. It is also not necessary to switch between a camera and a laser rangefinder to collect the data required for calibration, and it is not necessary for the human eye to identify the laser spots. The identification of the calibration plate is obtained through high-precision sub-pixel-level image processing, thereby ensuring the accuracy of positioning and measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of the dual turntable structure in the background art; Figure 2 It is an imaging schematic diagram of the pinhole imaging model; Figure 3 It is a schematic structural diagram of the pinhole imaging model in the five-axis device platform; Figure 4 It is a method flow chart of the calibration method of the five-axis device platform in one embodiment; Figure 5 It is a method flow chart of step S100 in the calibration method of the five-axis device platform in one embodiment; Figure 6 It is a schematic diagram of the calibration plate; Figure 7 It is a schematic diagram of the first center distance and the second center distance in one embodiment; Figure 8 It is a method flow chart of step S200 in the calibration method of the five-axis device platform in one embodiment; Figure 9 It is a method flow chart of step S400 in the calibration method of the five-axis device platform in one embodiment; Figure 10 It is a schematic diagram of the third center distance in one embodiment; Figure 11 It is a schematic structural diagram of calibrating the second rotating shaft in the five-axis device platform; Figure 12 It is a structural schematic diagram of a five-axis equipment platform in another embodiment. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are for making the present application better understood. However, those skilled in the art can easily recognize that some features can be omitted in different situations, or can be replaced by other elements, materials, methods. In some cases, some operations related to the present application are not shown or described in the specification, this is to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0020] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0021] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0022] The present application provides a five-axis device platform and a calibration method thereof. In the five-axis device platform and its corresponding calibration method, only a single camera is used, and positioning and autofocus are achieved through image positioning and measurement to obtain the spatial coordinate group required for the calibration of the two rotation axes of the dual-turntable five-axis device platform. The spatial vectors of the rotation axis center lines of the two rotation axes in the platform mechanical coordinate system are obtained through the spatial coordinate group. The present application can complete the calibration using the camera that comes with the five-axis device platform and a conventional calibration plate, without the need for calibration balls, ballbars, laser rangefinders and other devices. At the same time, the present application does not require a laser rangefinder, and autofocus can be achieved through image measurement technology to complete the ranging function, avoiding switching back and forth. In addition, the present application achieves autofocus through image measurement technology based on sub-pixel accuracy, indirectly realizes the ranging function, and avoids measurement errors caused by confirmation through human eye observation.

[0023] Please refer toFigure 2 In Figure 2 a to Figure 2 c. In one embodiment, a single camera and the imaging characteristics of the FA lens are used in a five-axis device platform to calibrate the centerline of the platform's rotation axis. The FA lens is an industrial lens that can obtain high-precision sub-pixel images, and its imaging model can be approximately regarded as a pinhole imaging model. In this model, the closer the object is to the lens, the larger the object image on the imaging plane. Conversely, the farther the object is, the smaller the image is. In other words, Figure 2 a to Figure 2 c, Figure 2 c. Figure 2 a and Figure 2 In b, the distance between the object being measured and the lens is getting closer and closer, and the obtained l2>l1>l3. Through this phenomenon, the present application uses the imaging characteristics of the lens and the camera to infer the distance and position of the object.

[0024] Please refer to Figure 3 In one embodiment, a calibration plate is fixed on the carrier of the five-axis device platform, and any two feature points are selected on the calibration plate, and the center distance between the two feature points in the platform coordinate system is a constant L. The camera's viewing angle will change as the platform's Z axis moves up and down. According to the imaging characteristics of the lens, the change in the Z axis position will cause the pixel distance between the two feature points on the calibration plate to change in the image coordinate system. When the Z axis rises, the pixel distance between the two feature points in the image becomes smaller; when the Z axis drops, the pixel distance between the two feature points in the image becomes larger. Since the actual distance between the two feature points on the calibration plate is known, and the pixel distance of the camera imaging is inversely proportional to the distance of the actual object, the actual Z axis position of the object on the platform can be inferred by measuring the change in pixel distance. Using the camera's image data and the imaging law of the FA lens, a function similar to a laser rangefinder can be realized, thereby calculating the real position and distance of the object. This application analyzes the pixel distance changes at different Z axis positions, combined with the conversion relationship between the image coordinate system and the platform coordinate system, and can infer the spatial vector of the rotation axis center line of the two rotation axes on the five-axis device platform in the platform mechanical coordinate system.

[0025] In one embodiment, the calibration of the camera coordinate system, the platform coordinate system, and the axis lines of two rotating axes is included in the five-axis equipment platform. The relative positions and rotational relationships of these coordinate systems determine the accuracy and performance of the five-axis equipment platform. The camera coordinate system is a coordinate system based on the camera lens itself, usually with the camera's light spot as the origin, and the axis direction is consistent with the camera's optical axis. During image processing, the camera coordinate system is used to determine the position of objects in the image. The platform coordinate system is a coordinate system related to the mechanical structure of the platform, used to describe the spatial positions and postures of various parts of the platform. Usually, the origin of the platform coordinate system is located at a certain reference point (such as the center point) of the platform, and the axis directions are aligned with the X-axis, Y-axis, and Z-axis of the platform. The axis line of the rotating axis refers to the rotation center line of each rotating axis in the five-axis equipment platform. Calibrating the spatial position and direction of this axis line is crucial for ensuring the accuracy of the platform's movement. The precise position of the rotating axis is usually determined by factors such as the platform's motion state, structural design, and rotation angle.

[0026] In one embodiment, the calibration between the camera coordinate system and the platform coordinate axes can be achieved by using a calibration board with known dimensions and feature points. Fix a calibration board with known dimensions and geometric structure on the carrier of the five-axis equipment platform. This calibration board is fixed at a known position and posture on the five-axis equipment platform. The camera takes images of the calibration board at different positions, and the feature points in the images are corresponded to the actual geometric positions in the platform coordinate system. Through a series of calibration points in the known coordinate system, the transformation matrix from the camera coordinate system to the platform coordinate system is calculated using geometric transformation methods. This transformation matrix describes the translation and rotation relationship between the camera coordinate system and the platform coordinate system.

[0027] In one embodiment, the movement of the five-axis equipment platform also includes two rotating axes. Each rotating axis has its unique axis line of rotation and rotation direction in space. If the spatial positions and directions of the two rotating axes are not accurately calibrated, errors will occur in their relationship, resulting in errors when the platform performs complex movements. Accurately calibrating the spatial vectors of the rotating axes can ensure the movement accuracy of each rotating axis of the platform, preventing inaccurate positioning caused by rotational errors. Therefore, this application provides a calibration method for the rotating axes, which will be specifically described below.

[0028] Please refer to Figure 4 , in one embodiment, this application provides a calibration method for a five-axis equipment platform, including the following steps.

[0029] Step S100: Adjust the carrier of the five-axis equipment platform so that the calibration board on the carrier is in a horizontal state, and obtain the first calibration data points of the linear motion axis.

[0030] In one embodiment, in the calibration method of a five-axis equipment platform, it is necessary to first level the carrier of the five-axis equipment platform so that the calibration plate on the carrier is in a horizontal state, that is, to determine the calibration reference state. At this time, the coordinate points of the linear motion axis in the five-axis equipment platform are obtained, and these coordinate points are corresponding to the first calibration data points, and the first calibration data points are also the calibration reference points.

[0031] Step S200: Drive the first rotation axis of the five-axis equipment platform to rotate a set number of times, and obtain the first spatial coordinate group when the center of the calibration plate coincides with the center of the camera field of view of the five-axis equipment platform after each rotation.

[0032] In one embodiment, when the carrier is in a horizontal state, drive the first rotation axis to rotate a set number of times. After each rotation, it is necessary to adjust the linear coordinate axes in the five-axis equipment platform so that the center of the calibration plate coincides with the center of the camera field of view of the five-axis equipment platform. Each time the linear coordinate axes follow the rotation of the first rotation axis and the center of the calibration plate coincides with the center of the camera field of view of the five-axis equipment platform, the coordinate points of the linear motion axis are obtained, and these coordinate points form the first spatial coordinate group.

[0033] Step S300: Calibrate the first rotation axis according to the first calibration data points and the first spatial coordinate group.

[0034] In one embodiment, calibrate the first rotation axis according to the first calibration data points and the first spatial coordinate group to determine the spatial vector of the axis line of the first rotation axis and complete the calibration of the axis line of the first rotation axis.

[0035] Step S400: Drive the second rotation axis of the five-axis equipment platform to rotate a set number of times, and obtain the second spatial coordinate group when the distance at the set position of the calibration plate is the preset measurement distance after each rotation.

[0036] In one embodiment, also when the carrier is in a horizontal state, drive the second rotation axis to rotate a set number of times. After each rotation, it is necessary to adjust the linear coordinate axes in the five-axis equipment platform so that the distance at the set position of the calibration plate is the preset measurement distance. Each time the linear coordinate axes follow the rotation of the second rotation axis and the distance at the set position of the calibration plate is adjusted to the preset measurement distance, the coordinate points of the linear motion axis are obtained, and these coordinate points are the second spatial coordinate group.

[0037] Step S500: Calibrate the second rotation axis according to the first calibration data points and the second spatial coordinate group.

[0038] In one embodiment, calibrate the second rotation axis according to the first calibration data points and the second spatial coordinate group to determine the spatial vector of the axis line of the second rotation axis and complete the calibration of the axis line of the second rotation axis.

[0039] It should be noted that the number of rotations of the first rotation axis and the second rotation axis is not limited. The number of rotations can be two or more, and can be set comprehensively according to accuracy and efficiency. Among them, for the first spatial coordinate group or the second spatial coordinate group obtained after each rotation, it is only necessary to combine them with the first calibration data points to determine the spatial vector of the axis line of the first rotation axis or the second rotation axis. Moreover, the order of first rotating the first rotation axis to obtain the first spatial coordinate group or first rotating the second rotation axis to obtain the second spatial coordinate group is not limited and can be set according to actual needs.

[0040] This application realizes the calibration of the spatial vectors of two rotation axes in the platform coordinate system by collecting the spatial point coordinate data required for calibrating the two rotation axes of the five-axis equipment platform. This application does not need to rely on a laser rangefinder or other high-precision devices to achieve during the calibration process, reducing the calibration cost. It also does not require switching between a camera and a laser rangefinder to collect the data required for calibration, nor does it require the human eye to identify laser spots and calibration plates. It is obtained through high-precision sub-pixel-level image processing, thereby ensuring the accuracy of positioning and measurement.

[0041] Please refer to Figure 5 , in an embodiment, when performing step S100 to adjust the stage of the five-axis equipment platform to make the calibration plate on the stage in a horizontal state and obtain the first calibration data points of the linear motion axis, the following steps are further included.

[0042] Step S110: Drive the first rotation axis and the linear motion axis to make the calibration plate in the camera's field of view.

[0043] In an embodiment, the first rotation axis in this application is the C axis, the second rotation axis is the A axis (or B axis), and the linear motion axes are the X axis, Y axis, and Z axis. Rotate the C axis to make the stage approximately in a horizontal state, fix the calibration plate at the middle position of the stage. At this time, move the X axis, Y axis, and Z axis to ensure that the entire calibration plate can be seen in the camera's field of view and the feature points on the calibration plate are in clear focus.

[0044] In an embodiment, select the first feature point, the second feature point, the third feature point, and the fourth feature point on the feature points of the calibration plate distributed in the first direction. Among them, the line connecting the first feature point and the second feature point is not collinear with the line connecting the third feature point and the fourth feature point, and the actual distance between the first feature point and the second feature point is equal to the actual distance between the third feature point and the fourth feature point. That is, the first feature point, the second feature point, the third feature point, and the fourth feature point can be selected on the calibration plate as needed, and adjacent feature points can be selected, or the feature points farthest apart can be selected.

[0045] It should be noted that the calibration plate used in this application is asFigure 6 As shown, it is a calibration board of 7×7, and the feature points are round dots. In addition, calibration boards of other specifications can also be used, and different calibration boards can be selected according to different requirements, or different feature points can be selected according to different calibration boards, which is not limited here. The following embodiments will be illustrated by taking a calibration board with 7×7 round dots as an example.

[0046] Step S120: In the camera's field of view, obtain the first center distance between the first feature point and the second feature point.

[0047] Step S130: In the camera's field of view, obtain the second center distance between the third feature point and the fourth feature point.

[0048] In one embodiment, after the calibration board is in the camera's field of view, keep the Z-axis unchanged and move the X-axis and Y-axis, and measure the calibration board through the camera. Through the image processing of the camera, measure the first center distance between the first feature point and the second feature point and the second center distance between the third feature point and the fourth feature point respectively.

[0049] It should be noted that in determining the first center distance and the second center distance, the first direction is Figure 3 the X-axis direction in the five-axis platform coordinate system. Any feature points on the feature points of the calibration board distributed in the first direction can also be selected as the first feature point and the second feature point. Similarly, the third feature point and the fourth feature point can also be any feature points, and the line connecting the first feature point and the second feature point is not collinear with the line connecting the third feature point and the fourth feature point. It only needs to ensure that the actual distance between the first feature point and the second feature point is equal to the actual distance between the third feature point and the fourth feature point, so that it can be ensured that the stage is in a horizontal state as long as the first center distance and the second center distance are equal in the camera's field of view. W Please refer to

[0050] In one embodiment, the first feature point and the second feature point are located at the top of the calibration board, and the third feature point and the fourth feature point are located at the bottom of the calibration board. In this application, the two feature points with the farthest distribution at the top of the calibration board are selected as the first feature point and the second feature point. Then, the first center distance is Figure 7 L1 in Figure 7 . The two feature points with the farthest distribution at the bottom of the calibration board are selected as the third feature point and the fourth feature point. Then, the second center distance is Figure 7 L2 in

[0051] Step S140: Drive the second rotating shaft and the linear motion shaft until the first center distance and the second center distance are equal.

[0052] In one embodiment, after measuring the first center distance L1 and the second center distance L2, compare the first center distance L1 and the second center distance L2. If the first center distance L1 and the second center distance L2 are not equal, adjust the rotation angle of the A axis. Each time the A axis rotates, finely adjust the X axis and the Y axis, and ensure that the center of the calibration plate coincides with the center of the camera's field of view after each adjustment. After the center of the calibration plate coincides with the center of the camera's field of view, measure the first center distance L1 and the second center distance L2 again until the first center distance L1 and the second center distance L2 are equal, which proves that the calibration plate on the stage is in a horizontal state.

[0053] It should be noted that even if the C axis is rotated to make the stage roughly horizontal, there may still be slight tilts or unevenness. This slight tilt will affect the center distance between two feature points in the camera's field of view, resulting in calibration errors. When the platform is not completely horizontal, the distances between the top and bottom feature points will be different. Measuring the first center distance L1 and the second center distance L2 can help determine whether there is a tilt on the stage. If only the distance of a group of feature points is measured during the leveling process, it may not comprehensively reflect the geometric shape of the platform. The distances between the top and bottom feature points provide a "top-bottom comparison" perspective, which can effectively detect any tilt or rotational error on the stage.

[0054] Step S150: Obtain the first calibration data point of the linear motion shaft.

[0055] In one embodiment, in the above steps, it has been determined that the calibration plate and the stage are in a horizontal state, and at this time, the center of the calibration plate has coincided with the center of the camera's field of view. Then, obtain the coordinates (x1, y1, z1) of the X axis, Y axis, and Z axis (i.e., the linear motion shaft) at this time as the first calibration data point P1. The first calibration data point P1 is also the calibration reference point.

[0056] Please refer to Figure 8 , in one embodiment, when performing step S200 to drive the first rotating shaft of the five-axis equipment platform to rotate a set number of times and obtain the first set of spatial coordinates when the center of the calibration plate coincides with the center of the camera's field of view of the five-axis equipment platform after each rotation, the following steps are also included.

[0057] Step S210: Drive the first rotating shaft of the five-axis equipment platform to rotate a set number of times and a first set angle.

[0058] In one embodiment, after determining the first calibration data point P1, drive the C axis to rotate a set number of times to determine the first set of spatial coordinates.

[0059] It should be noted that each rotation of the C-axis can be set within the range of 5° to 100°. Specifically, the rotation angle of the C-axis can be 10°, 20°, 30°, 60°, etc. The rotation angle of each rotation can be the same or different, and no limitation is made here.

[0060] Step S220: After each rotation of the first rotation axis, move the linear motion axis of the five-axis equipment platform so that the center of the calibration plate coincides with the camera field of view center of the five-axis equipment platform.

[0061] Step S230: Each time the center of the calibration plate coincides with the camera field of view center of the five-axis equipment platform, the coordinates of the linear motion axis form the first set of spatial coordinates.

[0062] In one embodiment, to ensure the smallest amount of calculation in this application, the C-axis is driven to rotate twice. Then, the first set of spatial coordinates includes the second calibration data point and the third calibration data point. After determining that the C-axis is driven to rotate twice, first drive the C-axis to perform the first rotation. After the C-axis rotates, move the X-axis and Y-axis to make the center of the calibration plate coincide with the camera field of view center again. At this time, record the coordinates of the current X-axis, Y-axis, and Z-axis of the five-axis equipment platform (x2, y2, z2) as the second calibration data point P2. Then, continue to drive the C-axis to perform the second rotation. After the C-axis rotates, move the X-axis and Y-axis again to make the center of the calibration plate coincide with the camera field of view center again. At this time, record the coordinates of the current X-axis, Y-axis, and Z-axis of the five-axis equipment platform (x3, y3, z3) as the third calibration data point P3.

[0063] In one embodiment, when calibrating the first rotation axis according to the first calibration data point and the first set of spatial coordinates in step S300, perform a cross product operation on the first calibration data point, the second calibration data point, and the third calibration data point to obtain the spatial vector of the C-axis rotation axis line in the platform coordinate system, thereby completing the calibration of the rotation axis line of the first rotation axis, that is, the calibration of the C-axis rotation axis line in this embodiment.

[0064] It should be noted that the rotation axis is a straight line. After the rotation of the C axis, the stage and the calibration plate will rotate along the C axis, and the position of the calibration plate in the camera's field of view will change. By recording different calibration data points at different C-axis angles, the projections of the calibration plate at different positions in space can be described. Since any two points can determine a straight line, three non-collinear points can define a unique plane, thereby determining the direction of the rotation axis. The spatial coordinate values of three calibration data points can calculate a set of vectors to help determine the spatial position of the C axis. If only two calibration data points are used, although a straight line can be defined, the certainty of this straight line is relatively low and it is easily affected by errors. By adding a third calibration data point, the error can be eliminated and the accuracy of the calculation result can be improved.

[0065] Please refer to Figure 9 , in one embodiment, when performing step S400 to drive the second rotation axis of the five-axis equipment platform to rotate a set number of times and obtain the second spatial coordinate group when the distance at the set position of the calibration plate after each rotation is the preset measurement distance, the following steps are further included.

[0066] Step S410: When the calibration plate is in a horizontal state, drive the second rotation axis of the five-axis equipment platform to rotate a set number of times and a second set angle.

[0067] In one embodiment, when calibrating the A axis, the five-axis equipment platform needs to be restored to the horizontal state of step S100 to ensure the accuracy of the A-axis calibration. After determining that the five-axis equipment platform has been restored to the horizontal state, drive the second rotation axis of the five-axis equipment platform to rotate a set number of times and a set angle.

[0068] It should be noted that each rotation of the A axis can be set within the range of 5° to 30°. Specifically, the rotation angle of the A axis can be 10°, 15°, or 20°, etc. The rotation angle of each rotation can be the same or different, and no limitation is made here. In addition, the first set angle and the second set angle can be the same or different, and no limitation is made here.

[0069] Step S420: After each rotation of the second rotation axis, move the linear motion axis of the five-axis equipment platform so that the distance at the set position of the calibration plate is the preset measurement distance.

[0070] In one embodiment, when the five-axis equipment platform is in a horizontal state, obtain the measurement distance of the set position of the calibration plate in the camera's field of view. The set position of the calibration plate is the middle area where the center of the calibration plate is located. Select any two feature points as the fifth feature point and the sixth feature point among the feature points in this middle area, then the distance between the fifth feature point and the sixth feature point is the measurement distance. In the horizontal state, the value measured for this measurement distance in the camera's field of view is the preset distance.

[0071] Please refer to Figure 10 , in one embodiment, the measured distance selected in the present application is the third central distance between the two feature points with the farthest distance along the first direction in the middle area of the calibration board, that is Figure 10 L0 in, wherein, the two feature points with the farthest distance along the first direction in the middle area are symmetrically distributed about the center of the calibration board.

[0072] It should be noted that during the calibration of the A-axis, using the third central distance L0 as the measured distance can ensure the focus consistency during the calibration process. By accurately measuring and controlling the measured distance, the accuracy and consistency of the camera focus can be ensured, and the measurement error introduced due to unclear focus can be avoided. Standardizing the third central distance L0 helps to unify each measurement to a fixed reference standard. This standardization ensures that when measuring each time, the positions and spacings of the feature points on the calibration board are compared under the same reference framework, reducing errors.

[0073] Step S430: When the distance at each set position of the calibration board is the preset measured distance, the coordinates of the linear motion axis are the second set of spatial coordinates.

[0074] Please refer to Figure 11 , in one embodiment, the calibration reference point determined when the stage of the five-axis equipment platform is in a horizontal state is also the fourth calibration point P4 required during the calibration of the second rotation axis. The determination method of the fourth calibration point P4 is the same as that of the first calibration point P1, and it can be saved and recorded, or recalibrated. After determining the fourth calibration data point P4, drive the A-axis to rotate a set number of times, thereby determining the second set of spatial coordinates. In order to ensure the smallest amount of calculation in the present application, the A-axis is driven to rotate twice. Then, the second set of spatial coordinates includes the fifth calibration data point and the sixth calibration data point. Specifically: drive the A-axis to rotate for the first time. After the A-axis rotates, move the X-axis and Y-axis to make the center of the calibration board coincide with the center of the camera's field of view again, and then slowly move the Z-axis until the distance between the two feature points with the farthest distance along the first direction in the middle area of the calibration board is the third central distance L0. At this time, record the coordinates of the current X-axis, Y-axis, and Z-axis of the five-axis equipment platform (x5, y5, z5) as the fifth calibration data point P5. Then, continue to drive the A-axis to rotate for the second time. After the A-axis rotates, move the X-axis and Y-axis again to make the center of the calibration board coincide with the center of the camera's field of view again, and then slowly move the Z-axis until the distance between the two feature points with the farthest distance along the first direction in the middle area of the calibration board is the third central distance L0. At this time, record the coordinates of the current X-axis, Y-axis, and Z-axis of the five-axis equipment platform (x6, y6, z6) as the sixth calibration data point P6.

[0075] In one embodiment, when calibrating the second rotation axis according to the first calibration data points and the second set of spatial coordinates in step S500, a cross product operation is performed on the fourth calibration data point, the fifth calibration data point, and the sixth calibration data point to obtain the spatial vector of the rotation axis of the A axis in the platform coordinate system, thereby completing the calibration of the rotation axis of the second rotation axis, that is, the calibration of the rotation axis of the A axis. Similarly, this method is also applicable to the calibration of the rotation axis of the B axis.

[0076] It should be noted that since any two points can determine a straight line, three non-collinear points can define a unique plane, thereby determining the direction of the rotation axis. The spatial coordinate values of the three calibration data points can calculate a vector set to help determine the spatial position of the A axis. If only two calibration data points are used, although a straight line can be defined, the certainty of this straight line is relatively low and is easily affected by errors. By adding a third calibration data point, errors can be eliminated and the accuracy of the calculation result can be improved.

[0077] In one embodiment, the order of steps S200 and S400 in this application can be exchanged. Since steps S200 and S400 have been clearly described in the above embodiments, the second rotation axis in step S400 can be calibrated first, and then the first rotation axis in step S200 can be calibrated. The calibration method is the same as above and will not be elaborated here.

[0078] This application realizes the calibration of the spatial vectors of two rotation axes in the platform coordinate system by collecting the spatial point coordinate data required for calibrating the two rotation axes of the five-axis equipment platform. This application does not need to rely on a laser rangefinder or other high-precision devices to achieve calibration during the calibration process, reducing the calibration cost. It also does not require switching between a camera and a laser rangefinder to collect the data required for calibration, nor does it require the human eye to identify laser spots and calibration plates. The identification is obtained through high-precision sub-pixel-level image processing, thereby ensuring the accuracy of positioning and measurement.

[0079] Please refer to Figure 12 , in another embodiment, a five-axis equipment platform 10 is provided, including a linear motion module 11, a rotational motion module 12, and a control module 13. The linear motion module 11 includes linear motion axes that move in the X-axis, Y-axis, and Z-axis directions perpendicular to each other. The rotational motion module 12 includes a first rotation axis and a second rotation axis, and the rotation axis of the first rotation axis is perpendicular to the rotation axis of the second rotation axis. The control module 13 uses the calibration method of the five-axis equipment platform in any of the above embodiments to calibrate the first rotation axis and the second rotation axis. Since the calibration method of the five-axis equipment platform has been clearly described in the above embodiments, it will not be elaborated here.

[0080] Those skilled in the art can understand that all or part of the functions of the various methods in the above embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above embodiments are implemented by computer programs, the programs can be stored in a computer-readable storage medium, which can include: read-only memory, random access memory, magnetic disks, optical disks, hard disks, etc. The above functions can be realized by executing the programs on a computer. For example, storing the programs in the memory of a device, when the programs stored in the memory are executed by a processor, the above all or part of the functions can be realized. In addition, when all or part of the functions in the above embodiments are implemented by computer programs, the programs can also be stored in storage media such as servers, other computers, magnetic disks, optical disks, flash drives or external hard drives, and saved to the memory of a local device by downloading or copying, or the system of the local device can be updated. When the programs stored in the memory are executed by a processor, all or part of the functions in the above embodiments can be realized.

[0081] The above uses specific examples to elaborate on the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the technical field to which the present invention pertains, several simple deductions, deformations or substitutions can be made according to the idea of the present invention.

Claims

1. A calibration method for a five-axis equipment platform, characterized in that: include: Adjusting the stage of the five-axis equipment platform so that the calibration plate on the stage is in a horizontal state, and obtaining a first calibration data point of the linear motion axis; Driving the first rotation axis of the five-axis device platform to rotate a set number of times, and obtaining a first spatial coordinate group when the center of the calibration plate coincides with the center of the camera field of view of the five-axis device platform after each rotation; calibrating the first rotation axis according to the first calibration data points and the first spatial coordinate group; Driving the second rotation axis of the five-axis device platform to rotate a set number of times, and obtaining a second spatial coordinate group when the distance of the set position of the calibration plate after each rotation is a preset measurement distance; The second rotation axis is calibrated according to the first calibration data points and the second spatial coordinate group.

2. The calibration method of the five-axis equipment platform according to claim 1, characterized in that: The step of adjusting the stage of the five-axis equipment platform so that the calibration plate on the stage is in a horizontal state comprises: Driving the first rotation axis and the linear motion axis to place the calibration plate in the camera field of view, wherein the calibration plate includes a first feature point, a second feature point, a third feature point, and a fourth feature point; In the camera field of view, obtaining a first center distance between the first feature point and the second feature point; In the camera field of view, obtaining a second center distance between the third feature point and the fourth feature point; The second rotation axis and the linear motion axis are driven until the first center distance and the second center distance are equal.

3. The calibration method of the five-axis equipment platform as claimed in claim 2, characterized in that: The first feature point and the second feature point are located at the top of the calibration plate; the third feature point and the fourth feature point are located at the bottom of the calibration plate; and the actual distance between the first feature point and the second feature point is equal to the actual distance between the third feature point and the fourth feature point.

4. The calibration method of the five-axis equipment platform according to claim 1, characterized in that: The method of driving the first rotation axis of the five-axis device platform to rotate a set number of times and obtaining a first spatial coordinate group when the center of the calibration plate coincides with the center of the camera field of view of the five-axis device platform after each rotation includes: Driving the first rotating axis of the five-axis equipment platform to rotate a set number of times and a first set angle; After each rotation of the first rotation axis, the linear motion axis of the five-axis device platform is moved so that the center of the calibration plate coincides with the center of the camera field of view of the five-axis device platform; Each time the center of the calibration plate coincides with the center of the camera field of view of the five-axis device platform, the coordinates of the linear motion axis constitute the first space coordinate group.

5. The calibration method of the five-axis equipment platform according to claim 1, characterized in that: The method of driving the second rotating axis of the five-axis device platform to rotate a set number of times and obtaining a second spatial coordinate group when the distance of the set position of the calibration plate after each rotation is a preset measurement distance includes: When the calibration plate is in a horizontal state, driving the second rotation axis of the five-axis equipment platform to rotate a set number of times and a second set angle; After each rotation of the second rotation axis, the linear motion axis of the five-axis equipment platform is moved so that the distance of the calibration plate setting position is the preset measurement distance. Each time the distance of the calibration plate setting position is the preset measurement distance, the coordinates of the linear motion axis constitute the second spatial coordinate group.

6. The calibration method of the five-axis equipment platform as claimed in claim 5, characterized in that: The set position of the calibration plate is the middle area where the center of the calibration plate is located; the calibration plate also includes a fifth feature point and a sixth feature point distributed in the middle area, and the preset measurement distance is the distance between the fifth feature point and the sixth feature point at the center of the camera field of view when the calibration plate is in a horizontal state.

7. The calibration method of the five-axis equipment platform according to claim 4 or 5, characterized in that: The first setting angle ranges from 5° to 100°; or, the second setting angle ranges from 5° to 30°.

8. The calibration method of a five-axis equipment platform according to any one of claims 1 to 6, characterized in that: The calibrating the first rotation axis according to the first calibration data point and the first spatial coordinate group includes: Performing a cross product on the first calibration data point and the first spatial coordinate group to determine the axis centerline spatial vector of the first rotation axis; or, The calibrating the second rotation axis according to the first calibration data point and the second space coordinate group includes: A cross product is performed on the first calibration data point and the second spatial coordinate group to determine the axis centerline spatial vector of the second rotation axis.

9. A five-axis equipment platform, characterized in that: include: The linear motion module includes linear motion axes moving in mutually perpendicular X-axis, Y-axis and Z-axis directions; A rotary motion module, comprising a first rotary shaft and a second rotary shaft, wherein a rotary axis of the first rotary shaft is perpendicular to a rotary axis of the second rotary shaft; The control module adopts the calibration method of the five-axis device platform as described in any one of claims 1 to 8 to calibrate the first rotation axis and the second rotation axis.

10. A computer-readable storage medium, wherein a computer program is stored on the medium, and the computer program can be executed by a processor to implement the calibration method of a five-axis device platform as claimed in any one of claims 1 to 8.

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