robotic arm calibration device

Abstract

One or more embodiments of this specification relate to a robotic arm calibration device, including multiple calibration arms and a positioning component. The multiple calibration arms are sequentially and movably connected. The relative positions between the multiple calibration arms and the relative positions between the multiple calibration arms and the robotic arm are fixed by the positioning component. The included angle between at least two adjacent connected calibration arms is set at a first angle.

Description

Technical Field

[0001] This specification relates to the field of calibration technology, and in particular to a robotic arm calibration device. Background Technology

[0002] With the development of robotics, control, and sensor technologies, intelligent robots are increasingly being used in numerous industries, such as machining, aerospace, military, and medical equipment. Intelligent robots typically require a certain level of absolute positioning accuracy and repeatability. To meet these requirements, joint calibration is necessary for each joint (e.g., a robotic arm) during the production and assembly process. The accuracy and ease of the calibration method not only affect the performance of the intelligent robot but also its production efficiency and cost.

[0003] For the reasons mentioned above, this specification provides a robotic arm calibration device. Each joint of the robotic arm calibration device can be precisely engaged with each joint of the robotic arm, eliminating the accuracy error generated when using the scribing calibration method. The calibration error only occurs when the robotic arm calibration device is assembled with the robotic arm, making the final calibration accuracy relatively controllable and able to meet the calibration requirements of more intelligent robots. Summary of the Invention

[0004] One embodiment of this specification provides a robotic arm calibration device, including multiple calibration arms and a positioning component. The multiple calibration arms are sequentially and movably connected. The relative positions between the multiple calibration arms and the relative positions between the multiple calibration arms and the robotic arm are fixed by the positioning component. The included angle between at least two adjacent connected calibration arms is set at a first angle. Attached Figure Description

[0005] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0006] Figure 1 A schematic diagram of the robotic arm calibration device shown in some embodiments of this specification;

[0007] Figure 2 yes Figure 1 A top view of the robotic arm calibration device in the image;

[0008] Figure 3 These are schematic diagrams of the robotic arm shown in some embodiments of this specification;

[0009] Figure 4 This is a partial structural schematic diagram of a robotic arm according to some embodiments shown in this specification;

[0010] Figure 5 This is a structural schematic diagram of the robotic arm and the robotic arm calibration device being fixed relative to each other according to some embodiments of this specification;

[0011] Figure 6 This is a schematic diagram illustrating the process of fixing the robotic arm and the robotic arm calibration device according to some embodiments of this specification;

[0012] Figure 7 This is a schematic diagram illustrating the calibration process of a robotic arm device according to some embodiments of this specification;

[0013] Figure 8 This is a schematic diagram of another process for calibrating the bend cylinder of a robotic arm according to some embodiments of this specification;

[0014] Figure 9 This is a schematic diagram of a laser beam irradiating a transparent plate according to some embodiments of this specification.

[0015] Reference numerals: Robotic arm calibration device 100; First calibration arm 111; Second calibration arm 112; Third calibration arm 113; Fourth calibration arm 114; Positioning assembly 120; First plunger 121; Cross bearing 122; Positioning hole 1231; Positioning post 1232; Connecting post 124; Second plunger 1251; Blocking element 1252; Laser post 1253; Laser 12531; Transparent plate 1254; Scale line 1255; First mounting hole 131; Second mounting hole 132; Third mounting hole 133; Robotic arm 200; Base coordinate disk 210; First transverse robotic arm 220; Second transverse robotic arm 230; Third transverse robotic arm 240; Longitudinal robotic arm 250; Bend cylinder 260. Detailed Implementation

[0016] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0017] In some solutions, the robotic arm of an intelligent robot can typically use precision instruments (such as laser trackers) to detect the pose of its end effector, and then use algorithms for calibration. While this calibration method offers high accuracy, the high cost of these precision instruments leads to excessively high calibration costs, and the time-consuming calibration process further reduces efficiency. In other solutions, the end effector of intelligent robots with lower precision requirements can be calibrated using scribing. However, the accuracy of this method is uncontrollable, it cannot compensate for errors generated during the robot's manufacturing and assembly process, and the alignment of the scribing lines introduces additional errors, making it difficult to meet the calibration requirements of typical intelligent robots.

[0018] This specification provides a robotic arm calibration device in some embodiments. The device includes multiple calibration arms and a positioning assembly. The multiple calibration arms are movably connected, and the positioning assembly can fix the relative positions between the multiple calibration arms and the relative positions between the multiple calibration arms and the robotic arm. Once the relative positions between the calibration arms and the robotic arm are fixed, and since the relative positions between the multiple calibration arms are also fixed and known, the robotic arm can be calibrated using the calibration arms.

[0019] In some cases, because robotic arm calibration devices calibrate robotic arms through calibration arms and positioning components, their overall structure is relatively simple, manufacturing costs are low, and they are suitable for large-scale production in workshops. Furthermore, calibrating a robotic arm using this device requires fewer steps and is more convenient. The positioning components fix the relative positions of multiple calibration arms to the robotic arm, so the final error only includes assembly errors when the robotic arm and calibration device are relatively fixed. This assembly error can be input into the robotic arm's control algorithm to compensate for the calibration parameters, making the calibration accuracy relatively controllable. In addition, because multiple calibration arms are relatively fixed through positioning components, the dimensions of the calibration arms and the relative positions of the multiple calibration arms can be changed when calibrating robotic arms of different sizes to adapt to the requirements of more calibration scenarios.

[0020] In some embodiments, combined with Figures 1-2 As shown, the robotic arm calibration device 100 may include multiple calibration arms and a positioning assembly 120. The multiple calibration arms are sequentially and movably connected, and the relative positions between the multiple calibration arms and between the multiple calibration arms and the robotic arm are fixed by the positioning assembly 120. The included angle between at least two adjacent connected calibration arms is set at a first angle.

[0021] In some embodiments, when calibrating the robotic arm, a robotic arm calibration device 100 corresponding to the robotic arm model can be selected. The calibration arm of the robotic arm calibration device 100 can have an arm length matching the robotic arm, thereby calibrating the length of each joint of the robotic arm using the arm length. The included angle between two adjacent calibration arms can be fixed, thereby calibrating the angle between each joint of the robotic arm. The included angle between two calibration arms refers to the angle between the extension directions of the two calibration arms. The arm length of the calibration arm refers to the length of the calibration arm, which can correspond to the arm length of the robotic arm at its zero position. For example, when a calibration arm is connected to two calibration arms respectively, the arm length of the calibration arm is the distance between the calibration arm and the two connection points of the two adjacent calibration arms. As another example, when a calibration arm is connected to only one calibration arm, the arm length of the calibration arm can be the length of the calibration arm itself. A joint refers to a structure of a robotic arm that is connected by means of rotational connection, fixed connection, or movable connection, such as the first horizontal robotic arm and the vertical robotic arm mentioned below. In some embodiments, the calibration of a robotic arm joint includes calibrating parameters such as joint length and the joint angle between two adjacent joints. For example, if a joint of the robotic arm is telescopic, to calibrate the length of that joint to zero, the joint can be stretched to match the length of the calibration arm. As another example, if two joints of the robotic arm are rotatably connected, to calibrate the angle between these two joints to be at a preset angle (e.g., 45 degrees) to zero, the angle between the two calibration arms can be set to 45 degrees. One calibration arm is then engaged with one of the joints, making the robotic arm parallel to the joint. The other joint is then rotated until it is parallel to the other calibration arm. At this point, the angle between the two robotic arms is equal to 45 degrees, thus completing the zero-point calibration of the angle between the two joints.

[0022] Based on the calibration principle of the robotic arm calibration device 100, the included angle between two adjacent calibration arms needs to be determined before calibration, according to the calibration requirements for each joint of the robotic arm. Therefore, in this embodiment, the first angle refers to the included angle between two adjacent calibration arms determined based on the calibration requirements for each joint of the robotic arm. For example, if the calibration requirement for the included angle between two adjacent joints is 45 degrees, then the first angle between the two calibration arms used for calibration is 45 degrees. In some embodiments, the first angle can be changed according to the calibration requirements for each joint of the robotic arm. For example, if the calibration requirement for the included angle between two adjacent joints is 90 degrees, then the first angle between the two calibration arms used for calibration is 90 degrees.

[0023] Fixing the relative position between multiple calibration arms refers to fixing the included angle between two adjacent calibration arms. Fixing the included angle between adjacent calibration arms can be achieved by fixing the relative position of the two calibration arms using a positioning component.

[0024] In some embodiments, the length of the calibration arm may be fixed. In some embodiments, the length of the calibration arm may be adjustable. For example, in some embodiments of this specification, the length of the calibration arm may be adjusted by a first distance adjustment device and a second distance adjustment device, as detailed in the following description, which will not be repeated here.

[0025] In some embodiments, the active connection may include a rotatable connection, a sliding connection, a telescopic connection, etc. For example, the first calibration arm 111 hereinafter may be rotatably connected to the second calibration arm 112. As another example, the third calibration arm 113 hereinafter may be movable relative to the second calibration arm 112 along the extension direction of the second calibration arm 112.

[0026] In some embodiments, the relative positions between the plurality of calibration arms may include the relative positions between two adjacent calibration arms. For example, the first calibration arm 111 and the second calibration arm 112 are rotatably connected, and the positioning assembly 120 can fix the included angle between the first calibration arm 111 and the second calibration arm 112. In some embodiments, the relative positions between the plurality of calibration arms may include the relative positions between two non-adjacent calibration arms. For example, in Figure 1 In the embodiment shown, the third calibration arm 113 and the first calibration arm 111 and the second calibration arm 112 are all fixed by the positioning component 120, so the relative position between the third calibration arm 113 and the first calibration arm 111 is also fixed.

[0027] To facilitate the description of the structure and calibration principle of the robotic arm calibration device 100, this specification provides an exemplary robotic arm 200, in conjunction with... Figures 3-4 As shown, the robotic arm 200 includes a base coordinate disk 210, a lateral robotic arm (e.g., a first lateral robotic arm 220), a longitudinal robotic arm 250, and a bend cylinder 260. The first lateral robotic arm 220 is rotatably connected to the base coordinate disk 210, and the rotation axis of the first lateral robotic arm 220 and the base coordinate disk 210 is parallel to the thickness direction of the base coordinate disk 210. The thickness direction of the base coordinate disk 210 can be... Figure 3 Arrow X in the diagram indicates this. One end of the longitudinal robotic arm 250 is connected to the first transverse robotic arm 220 and can move relative to the first transverse robotic arm 220 along its extension direction. The extension direction of the longitudinal robotic arm 250 is parallel to the thickness direction of the base coordinate disk 210. The other end of the longitudinal robotic arm 250 has a curved cylinder 260, which can extend and retract along the extension direction of the longitudinal robotic arm 250 and rotate relative to the longitudinal robotic arm 260 along its extension direction. Therefore, the entire robotic arm 200 has four degrees of freedom, namely the degree of freedom of rotation of the first transverse robotic arm 220 relative to the base coordinate disk 210 (e.g., ...). Figure 3(As shown by the middle arrow M1), the degrees of freedom of the longitudinal robotic arm 250 to move along the extension direction of the first transverse robotic arm 220 (e.g.) Figure 3 (As shown by the middle arrow M2), the degrees of freedom of the curved cylinder 260 to extend and retract along the longitudinal extension direction of the robotic arm 250 (e.g.) Figure 3 (As shown by the middle arrow M3), and the degrees of freedom of the curved cylinder 260 to rotate along the extension direction of the longitudinal robotic arm 250 (as shown by the middle arrow M3). Figure 3 (As indicated by the middle arrow M4).

[0028] It should be noted that the structure of the robotic arm 200 in the embodiments of this specification is for illustrative purposes only and is not intended to limit the specific structure of the robotic arm 200. For example, in addition to the first horizontal robotic arm 220, other horizontal robotic arms (such as the second horizontal robotic arm 230 and the third horizontal robotic arm 240 described below) can also be connected to the base coordinate disk 210.

[0029] In some embodiments, combined with Figures 1-4 As shown, the plurality of calibration arms includes at least a first calibration arm 111 and a second calibration arm 112, which are rotatably connected. The positioning assembly 120 includes a first positioning member. When the first positioning member is simultaneously connected to both the first calibration arm 111 and the second calibration arm 112, the included angle between the first calibration arm 111 and the second calibration arm 112 is fixed. When the first positioning member is not simultaneously connected to both the first calibration arm 111 and the second calibration arm 112, the first calibration arm 111 and the second calibration arm 112 can rotate relative to each other.

[0030] In this embodiment, the robotic arm calibration device 100 can be used to calibrate the zero position of the rotational degree of freedom of the first lateral robotic arm 220 relative to the base coordinate disk 210. That is, when the first lateral robotic arm 220 rotates to a certain angle relative to the base coordinate disk 210, the position of the first lateral robotic arm 220 is taken as the zero position of the rotational degree of freedom of the first lateral robotic arm 220 relative to the base coordinate disk 210. The angle between the first lateral robotic arm 220 and the base coordinate disk 210 refers to the angle between the extension direction of the first lateral robotic arm 220 and the base coordinate axis of the base coordinate disk 210 (e.g., ...). Figure 3 The direction indicated by the straight line O in the figure) and the rotation axis of the first transverse robotic arm 220 (as shown in the figure) Figure 3 The angle between the lines connecting the rotation axes of M1 in the model. The base coordinate axis refers to the axis used as an assembly reference when assembling the robotic arm calibration device 100 and the robotic arm 200. In some embodiments, the base coordinate axis may be an axis determined artificially and parallel to the thickness direction of the base coordinate disk 210. In some embodiments, the base coordinate axis may be an axis parallel to the thickness direction of the base coordinate disk 210 and passing through the geometric center of the base coordinate disk 210. For example, when the base coordinate disk 210 is a disk structure, the base coordinate axis may coincide with the central axis of the disk structure.

[0031] Before calibrating the zero position of the rotational degree of freedom of the first transverse robotic arm 220 relative to the base coordinate disk 210, the included angle between the first calibration arm 111 and the second calibration arm 112 needs to be set to the angle corresponding to the zero position of the rotational degree of freedom. Then, the first calibration arm 111 and the second calibration arm 112 are respectively engaged with the first transverse robotic arm 220 and the base coordinate disk 210. When the extension direction of the first calibration arm 111 is aligned with the base coordinate axis of the base coordinate disk 210 (e.g., ...), ... Figure 3 The direction indicated by the straight line O in the figure) and the rotation axis of the first transverse robotic arm 220 (as shown in the figure) Figure 3 When the lines connecting the rotation axes of M1 and M1 are parallel, and the second calibration arm 112 is parallel to the first transverse robotic arm 220, the angle between the first transverse robotic arm 220 and the base coordinate disk 210 is the angle corresponding to the zero position of the rotational degree of freedom. In some cases, since the first calibration arm 111 and the second calibration arm 112 are rotatably connected, the angle between the first calibration arm 111 and the second calibration arm 112 can be flexibly adjusted to meet the needs of different calibration scenarios when the required angles corresponding to the zero position of the rotational degree of freedom of the transverse robotic arm are different. After the first positioning component is set, the restriction on the relative rotation of the first calibration arm 111 and the second calibration arm 112 can be released before calibration. For example, when the first positioning component is not connected to the first calibration arm 111 and the second calibration arm 112 at the same time, the first positioning component cannot restrict the relative rotation of the first calibration arm 111 and the second calibration arm 112. Thus, the included angle between the first calibration arm 111 and the second calibration arm 112 can be adjusted according to the angle corresponding to the zero position of the required rotational degree of freedom of the lateral robot arm. Then, the first positioning component is connected to the first calibration arm 111 and the second calibration arm 112 to fix the included angle between the first calibration arm 111 and the second calibration arm 112.

[0032] In some embodiments, such as Figure 2 and Figure 6 As shown, the first calibration arm 111 and the second calibration arm 112 can be connected by a cross bearing 122, and the first calibration arm 111 and the second calibration arm 112 can rotate relative to the central axis of the cross bearing 122. As an example only, the first calibration arm 111 is connected to the cross bearing 122, and the direction of the central axis of the cross bearing 122 is parallel to the thickness direction of the first calibration arm 111 (i.e., the first calibration arm 111 is in...). Figure 6 The dimensions in the X direction of the middle arrow are parallel. The cross bearing 122 and the second calibration arm 112 are connected by a connecting post 124. The connecting post 124 can rotate relative to the central axis of the cross bearing 122, thereby driving the second calibration arm 112 to rotate relative to the first calibration arm 111.

[0033] In some embodiments, when both the first calibration arm 111 and the second calibration arm 112 are connected to the first positioning member, the included angle between the first calibration arm 111 and the second calibration arm 112 is 90 degrees.

[0034] In some embodiments, the included angle between the first calibration arm 111 and the second calibration arm 112 is related to the calibration included angle between the first lateral robotic arm 220 and the base coordinate disk 210. When the calibration included angle between the first lateral robotic arm 220 and the base coordinate disk 210 is different, the included angle between the first calibration arm 111 and the second calibration arm 112 (i.e., the first angle) may also change. For example, in Figure 5 In the illustrated embodiment, if the angle between the first lateral robotic arm 220 and the base coordinate disk 210 is 90 degrees, it is calibrated to the zero position. Therefore, the angle between the first calibration arm 111 and the second calibration arm 112 (i.e., the angle between the extension directions of the first calibration arm 111 and the second calibration arm 112) needs to be set to 90 degrees. Alternatively, if the angle between the first lateral robotic arm 220 and the base coordinate disk 210 is 75 degrees, it is calibrated to the zero position. Therefore, the angle between the first calibration arm 111 and the second calibration arm 112 needs to be set to 75 degrees. In some embodiments, the angle between the first calibration arm 111 and the second calibration arm 112 can be 30 degrees, 45 degrees, 60 degrees, etc.

[0035] In some embodiments, before calibrating the robotic arm 200, the robotic arm calibration device 100 needs to be fixed to the base coordinate disk 210. In some embodiments, the positioning assembly 120 includes a fixing member disposed on the first calibration arm 111, and the first calibration arm 111 and the robotic arm 200 are fixed and positioned by the fixing member. This is merely an example. Figure 6 As shown, the fixing component may include a positioning post 1232 and a positioning hole 1231. One end of the first calibration arm 111 is provided with the positioning post 1232, and the base coordinate disk is provided with the positioning hole 1231. The central axis of the positioning hole 1231 coincides with the base coordinate axis O. The first calibration arm 111 is fixed to the base coordinate disk 210 through the cooperation of the positioning post 1232 and the positioning hole 1231. When the first calibration arm 111 is fixed to the base coordinate disk 210, since the connection point between one end of the first calibration arm 111 and the robot arm 200 is located on the base coordinate axis, the position where the first calibration arm 111 coincides with the base coordinate axis O can be the base point of the robot arm calibration device 100. Similarly, the other end of the first calibration arm 111 can also be fixed to the base coordinate disk 210 by the fixing component. In some embodiments, the connection point between the other end of the first calibration arm 111 and the robot arm 200 coincides with the rotation axis of the base calibration disk 210 and the first transverse robot arm 220.

[0036] In some embodiments, such as Figure 4As shown, in addition to the first lateral robotic arm 220, the base coordinate disk 210 can also connect to other lateral robotic arms, each of which can be connected to a different position on the base coordinate disk 210. By way of example only, the lateral robotic arms may include a first lateral robotic arm 220, a second lateral robotic arm 230, and a third lateral robotic arm 240. At least two of the first lateral robotic arms 220, the second lateral robotic arm 230, and the third lateral robotic arm 240 can be rotatably connected to the base coordinate disk 210 simultaneously, or one of the first lateral robotic arms 220, the second lateral robotic arm 230, and the third lateral robotic arm 240 can be rotatably connected to the base coordinate disk 210. For example, Figure 3 In this configuration, only the first lateral robotic arm 220 is connected to the base coordinate disk 210. In some embodiments, within a plane perpendicular to the thickness direction of the base coordinate disk 210, the extension axis of the first lateral robotic arm 220 (e.g., ...) Figure 4 The distance between the dashed line P (as shown in the diagram) and the rotation axis of the first horizontal robotic arm 220 and the base coordinate disk 210 is a certain distance, which can be called the offset distance e. The offset distance e can be set as needed, for example, as shown in the diagram. Figure 4 As shown, no offset distance needs to be set between the extension axis of the second horizontal robotic arm 230 and the rotation axis of the second horizontal robotic arm 230 and the base coordinate disk 210, i.e., the offset distance e is 0. For example, as... Figure 4 As shown, the extension axis of the third lateral robotic arm 240 may have an offset distance e between the third lateral robotic arm 240 and the rotation axis of the base coordinate disk 210. In some embodiments, the offset distance e between the plurality of lateral robotic arms and their respective rotation axes relative to the base coordinate disk 210 may be the same or different.

[0037] In some embodiments, the second calibration arm 112 includes multiple mounting positions, and the first calibration arm 111 is rotatably connected to one of these mounting positions. The first calibration arm 111 is mounted at different mounting positions to match the offset distance e of the robotic arm, thereby achieving accurate calibration.

[0038] As an example only, in Figure 2 In the illustrated embodiment, the second calibration arm 112 has three mounting holes: a first mounting hole 131, a second mounting hole 132, and a third mounting hole 133. The first calibration arm 111 can be connected to one of these mounting holes. When the first calibration arm 111 is connected to different mounting holes, it corresponds to different mounting positions. For example, when the first calibration arm 111 is connected to the first mounting hole 131, it corresponds to the first mounting position; when the first calibration arm 111 is connected to the second mounting hole 132, it corresponds to the second mounting position; and when the first calibration arm 111 is connected to the third mounting hole 133, it corresponds to the third mounting position.

[0039] In some embodiments, depending on the position of the lateral robotic arm connected to the base coordinate disk 210, the first calibration arm 111 can be connected to different mounting holes to calibrate different lateral robotic arms. For example, combined with Figures 2-4 As shown, the first mounting hole 131 and the third mounting hole 133 are symmetrically arranged with respect to the extension direction of the second calibration arm 112, and the first mounting hole 131 and the third mounting hole 133 are aligned with the extension axis of the second calibration arm 112 (e.g., ...). Figure 2 (As shown by the dashed line Q) are spaced at a certain distance, which is equal to the offset distance e. Therefore, when calibrating the first horizontal robotic arm 220 and the base coordinate disk 210, the other end of the first calibration arm 111 can be connected to the first mounting hole 131, and the first mounting hole 131 can be aligned with the rotation axis of the first horizontal robotic arm 220 and the base coordinate disk 210. At this time, in the plane perpendicular to the thickness direction of the base coordinate disk 210, the projection of the extension axis of the first horizontal robotic arm 220 coincides with the projection of the extension axis of the second calibration arm 112. When calibrating the second horizontal robotic arm 230 and the base coordinate disk 210, the other end of the first calibration arm 111 can be connected to the second mounting hole 132, and the second mounting hole 132 can be aligned with the rotation axis of the second horizontal robotic arm 230 and the base coordinate disk 210. At this time, in the plane perpendicular to the thickness direction of the base coordinate disk 210, the projection of the extension axis of the first horizontal robotic arm 220 coincides with the projection of the extension axis of the second calibration arm 112. The method for calibrating the third horizontal robotic arm 240 and the base coordinate disk 210 is similar to that for calibrating the first horizontal robotic arm 220 and the base coordinate disk, and will not be described in detail here.

[0040] It should be noted that, Figures 2-4 The examples shown regarding the number of mounting positions and their relative positions are for illustrative purposes only and are not intended to limit the number of mounting positions or their relative positions. Those skilled in the art, understanding the principle of the robotic arm calibration device 100, can adjust the number of mounting positions and their relative positions. For example, if the number of lateral robotic arms connected to the base coordinate disk 210 increases, the number of mounting positions (i.e., mounting holes on the second calibration arm 112) can be increased accordingly. As another example, the distance between the corresponding mounting hole and the extension direction of the second calibration arm 112 can be adjusted according to the offset distance e between the extension direction of the lateral robotic arm and the rotation axis relative to the base coordinate disk 210.

[0041] In some embodiments, the first positioning element includes a first plunger 121, and the first calibration arm 111 is connected to one of a plurality of mounting positions via at least one first plunger 121. For example, in Figure 6In the embodiment shown, the first plunger 121 may include three. The three first plungers 121 are not located on the same straight line. When the three first plungers 121 are connected to the first calibration arm 111 and the second calibration arm 112, the three first plungers 121 can pass through the second calibration arm 112 to restrict the relative rotation of the first calibration arm 111 and the second calibration arm 112, ensuring that the included angle between the first calibration arm 111 and the second calibration arm 112 will not change during the calibration process, thus ensuring calibration accuracy.

[0042] In some embodiments, the plurality of calibration arms further includes a third calibration arm 113 and a fourth calibration arm 114, wherein the second calibration arm 112 and the third calibration arm 113 are movably connected, and the third calibration arm 113 and the fourth calibration arm 114 are movably connected. The positioning assembly 120 further includes a second positioning member, wherein the relative positions of the second calibration arm 112, the third calibration arm 113, and the fourth calibration arm 114 with the robotic arm 200 are fixed by the second positioning member.

[0043] In this embodiment, since the first horizontal robotic arm 220 has a degree of freedom to rotate relative to the base coordinate disk 210, the calibration of the first horizontal robotic arm 220 can include rotation angle calibration. The vertical robotic arm 250 has a degree of freedom to move relative to the extension direction of the first horizontal robotic arm 220, therefore the calibration of the vertical robotic arm 250 can include distance calibration of the vertical robotic arm 250, where the distance refers to the distance between the vertical robotic arm 250 and the rotation axis of the first horizontal robotic arm 220 and the base coordinate disk 210.

[0044] In some embodiments, the included angle between the second calibration arm 112 and the third calibration arm 113 and the included angle between the longitudinal robotic arm 250 and the first transverse robotic arm 220 (i.e., the included angle between the extension direction of the longitudinal robotic arm 250 and the extension direction of the first transverse robotic arm 220) are the same or similar to achieve the engagement of the robotic arm 200 with the robotic arm calibration device 100. Similarity means that the difference between the included angle between the second calibration arm 112 and the third calibration arm 113 and the included angle between the longitudinal robotic arm 250 and the first transverse robotic arm 220 does not exceed 1 degree, 2 degrees, 5 degrees, etc. For example, in Figure 5In the illustrated embodiment, the included angle between the longitudinal robotic arm 250 and the first transverse robotic arm 220 is 90 degrees (the included angle between the longitudinal robotic arm 250 and the first transverse robotic arm 220 is fixed), so that when the first transverse robotic arm 220 is parallel to the second calibration arm 112, the longitudinal robotic arm 250 can be parallel to the third calibration arm 113. At this time, the distance of the longitudinal robotic arm 250 can be calibrated based on the distance from the third calibration arm 113 to the rotation axis of the first calibration arm 111 and the second calibration arm 112 (which coincides with the rotation axis of the first transverse robotic arm 220 and the base coordinate disk 210), and the distance between the third calibration arm 113 and the longitudinal robotic arm 250. Therefore, the included angle between the second calibration arm 112 and the third calibration arm 113 is 90 degrees.

[0045] In some embodiments, the angle between the third calibration arm 113 and the fourth calibration arm 114 is related to the angle between the extension direction of the curved cylinder 260 and the longitudinal robotic arm 250. In some embodiments, the extension direction of the fourth calibration arm 114 is perpendicular to the extension direction of the curved cylinder 260, and when the fourth calibration arm 114 abuts against the curved cylinder 260, the third calibration arm 113 is parallel to the longitudinal robotic arm 250. For example, in Figure 5 In the embodiment shown, the extension direction of the curved cylinder 260 is parallel to the extension direction of the longitudinal robotic arm 250. Therefore, the angle between the third calibration arm 113 and the fourth calibration arm 114 is 90 degrees, so that when the fourth calibration arm 114 comes into contact with the curved cylinder 260, the third calibration arm 113 is parallel to the longitudinal robotic arm 250.

[0046] In some embodiments, the second positioning member includes a second plunger 1251, the extension direction of which is parallel to the extension direction of the second calibration arm 112. When the second plunger 1251 connects the third calibration arm 113 to the robotic arm 200, and one end of the fourth calibration arm 114 away from the third calibration arm 113 abuts against the robotic arm 200, the relative positions of the second calibration arm 112 and the third calibration arm 113 with the robotic arm 200 are fixed.

[0047] In this embodiment, when calibrating the rotational degrees of freedom of the first horizontal robotic arm 220, since the included angle (e.g., 90 degrees) between the first calibration arm 111 and the second calibration arm 112 has been determined, and the first calibration arm 111 is relatively fixed to the base coordinate disk 210, as long as the extension direction of the first horizontal robotic arm 220 is parallel to the extension direction of the second calibration arm 112, it indicates that the included angle between the first horizontal robotic arm 220 and the base coordinate disk 210 is the same as the included angle between the first calibration arm 111 and the second calibration arm 112, thus achieving the calibration of the rotational angle of the first horizontal robotic arm 220. Based on the above, it can be seen that calibrating the rotational degrees of freedom of the first horizontal robotic arm 220 involves rotating the first horizontal robotic arm 220 so that its extension direction is parallel to the extension direction of the second calibration arm 112. When the first horizontal robotic arm 220 rotates, it also drives the longitudinal robotic arm 250 to rotate. Since the extension direction of the second plunger 1251 is parallel to the extension direction of the second calibration arm 112, when the second plunger 1251 connects the second calibration arm 112 and the longitudinal robotic arm 250, it indicates that the extension direction of the first transverse robotic arm 220 is parallel to the extension direction of the second calibration arm 112. At this time, the rotational degree of freedom of the first transverse robotic arm 220 relative to the base coordinate disk 210 is zero. Furthermore, when the second plunger 1251 connects the second calibration arm 112 and the longitudinal robotic arm 250, the second plunger 1251 can restrict the first transverse robotic arm 220 from continuing to rotate; therefore, the first transverse robotic arm 220 and the second calibration arm 112 can be considered relatively fixed.

[0048] When calibrating the distance of the longitudinal robotic arm 250, since the distance between the rotation axes of the third calibration arm 113 and the first calibration arm 111 and the second calibration arm 112 has been determined, when the extension direction of the third calibration arm 113 is parallel to the extension direction of the longitudinal robotic arm 250, the distance of the longitudinal robotic arm 250 can be determined based on the distance between the rotation axes of the third calibration arm 113 and the first calibration arm 111 and the second calibration arm 112, as well as the distance between the third calibration arm 113 and the longitudinal robotic arm 250, thus achieving the distance calibration of the longitudinal robotic arm 250. Since the extension direction of the curved cylinder 260 is parallel to the extension direction of the longitudinal robotic arm 250, and the angle between the fourth calibration arm 114 and the third calibration arm 113 is 90 degrees, when the end of the fourth calibration arm 114 away from the third calibration arm 113 abuts against the curved cylinder 260, it indicates that the extension direction of the longitudinal robotic arm 250 is parallel to the extension direction of the third calibration arm 113. At this time, the distance calibration of the longitudinal robotic arm 250 can be achieved, and the longitudinal robotic arm 250 and the third calibration arm 113 can be considered to be relatively fixed.

[0049] In some embodiments, the second plunger 1251 can switch between an unlocked position and a locked position. When the second plunger 1251 moves to the locked position, the relative position of the third calibration arm 113 and the robotic arm 200 is fixed. When the second plunger 1251 moves to the unlocked position, the fixed relationship between the second calibration arm 112 and the robotic arm 200 is released. As an example only, one end of the second plunger 1251 passes through a through-hole on the third calibration arm 113, and the other end of the second plunger 1251 is connected to the third calibration arm 113 via an elastic element. The elastic element allows the second plunger 1251 to move in the extending direction of the second calibration arm 112. When the elastic element is in its natural state, one end of the second plunger 1251 protrudes from the through-hole of the third calibration arm 113, at which point the second plunger 1251 is in the locked position. When the elastic element is pulled, it causes the second plunger 1251 to move, i.e., to move towards the unlocked position. The positioning assembly 120 also includes a blocking member 1252, which is connected to the longitudinal robotic arm 250. A transverse track parallel to the extension direction of the first transverse robotic arm 220 is provided on the first transverse robotic arm 220, and both the blocking member 1252 and the longitudinal robotic arm 250 are located on the transverse track. When calibrating the rotational degrees of freedom of the first transverse robotic arm 220, the second plunger 1251 can be adjusted to the locked position, and then the longitudinal robotic arm 250 can be rotated. Since the first calibration arm 111 is fixed to the base coordinate disk 210, and the angle between the first calibration arm 111 and the second calibration arm 112 is 90 degrees, when the blocking member 1252 abuts against the second plunger 1251, it indicates that the angle between the first transverse robotic arm 220 and the base coordinate disk 210 is 90 degrees. Furthermore, since the second plunger 1251 abuts against the longitudinal robotic arm 250, the second plunger 1251 can restrict the first transverse robotic arm 220 from continuing to rotate relative to the base coordinate disk 210, thereby fixing the second calibration arm 112 relative to the first transverse robotic arm 220.

[0050] In some embodiments, the cross-sectional area of ​​the curved cylinder 260 along the extension direction of the longitudinal robotic arm 250 is smaller than the cross-sectional area of ​​the longitudinal robotic arm 250 along its own extension direction. When the second plunger 1251 connects the third calibration arm 113 to the longitudinal robotic arm 250, the end of the fourth calibration arm 114 away from the third calibration arm 113 may not abut against the curved cylinder 260. However, the elastic element allows the second plunger 1251 to have a certain amount of movement space in its own extension direction, enabling the longitudinal robotic arm 250 to continue moving towards the base coordinate disk 210 after contacting the second plunger 1251. This allows the end of the fourth calibration arm 114 away from the third calibration arm 113 to abut against the curved cylinder 260. When the end of the fourth calibration arm 114 away from the third calibration arm 113 abuts against the curved cylinder 260, the extension direction of the third calibration arm 113 can be considered parallel to the extension direction of the longitudinal robotic arm 250 to achieve distance calibration of the longitudinal robotic arm 250.

[0051] In some embodiments, the third calibration arm 113 can move relative to the second calibration arm 112 along the extension direction of the second calibration arm 112 to adjust the distance between the third calibration arm 113 and the rotation axis of the second calibration arm 112 and the first calibration arm 111 according to the distance calibration requirements of the longitudinal robotic arm 250, thereby adapting to more calibration scenarios. In some embodiments, the robotic arm calibration device 100 further includes a first distance adjustment device (not shown in the figure), which is configured to adjust the movement distance of the second calibration arm 112 in the extension direction of the third calibration arm 113. For example, the first distance adjustment device may include a first slider and a first slide rail adapted to the first slider. The first slider may be disposed on the third calibration arm 113, and the first slide rail may be disposed on the second calibration arm 112, with the extension direction of the first slide rail parallel to the extension direction of the second calibration arm 112. The movement distance of the third calibration arm 113 in the extension direction of the second calibration arm 112 is adjusted by moving the first slider relative to the first slide rail.

[0052] In some embodiments, the second calibration arm 112 may be movable relative to the third calibration arm 113 along the extension direction of the third calibration arm 113. As an example only, when the thickness of the base coordinate disk 210 (i.e., the base coordinate disk 210 in...) Figure 3 As the dimension in the X direction (as indicated by the middle arrow) increases, the distance between the first transverse robotic arm 220 and the second calibration arm 112 increases. Therefore, to make the second calibration arm 112 perpendicular to the third calibration arm 113, it is necessary to control the second calibration arm 112 to move towards the fourth calibration arm 114 along the extension direction of the third calibration arm 113. In some embodiments, the first distance adjustment device can also be configured to adjust the movement distance of the third calibration arm 113 in the extension direction of the second calibration arm 112. Similarly, the first distance adjustment device may include a second slider and a second slide rail adapted to the second slider, and the movement distance of the second calibration arm 112 in the extension direction of the third calibration arm 113 is adjusted by moving the second slider relative to the second slide rail, which will not be described in detail here.

[0053] In some embodiments, after the second calibration arm 112 and the third calibration arm 113 are connected, their relative positions are fixed, meaning they cannot move relative to each other. Exemplarily, the connection methods for the second calibration arm 112 and the third calibration arm 113 may include snap-fit ​​connection, magnetic connection, pin connection, adhesive bonding, screw and nut connection, etc. For example, the third calibration arm 113 has a socket, and the end of the second calibration arm 112 away from the first calibration arm 111 has a pin adapted to the socket. The connection between the second calibration arm 112 and the third calibration arm 113 can be achieved through the cooperation of the pin and the socket.

[0054] In some embodiments, combined with Figures 5-9As shown, the second positioning element also includes a laser column 1253 and at least two transparent plates 1254. The laser column 1253 is disposed on the robotic arm 200 and can emit a laser 12531. The at least two transparent plates 1254 are disposed at the end of the third calibration arm 113 away from the second calibration arm 112, and are spaced apart along the extension direction of the fourth calibration arm 114. The at least two transparent plates 1254 are provided with scale lines 1255. When the laser 12531 emitted by the laser column 1253 illuminates the same scale on the at least two transparent plates 1254 along the extension direction of the fourth calibration arm 114, the relative position of the fourth calibration arm 114 and the robotic arm 200 is fixed.

[0055] As can be seen from other embodiments of this specification, the curved cylinder 260 of the robotic arm 200 can extend and retract along the longitudinal extension direction of the robotic arm 250, and rotate along the longitudinal extension direction of the robotic arm 250. Therefore, the curved cylinder 260 has two degrees of freedom of motion. Thus, the calibration of the robotic arm 200 also includes calibrating the two degrees of freedom of motion of the curved cylinder 260, namely, the calibration of the degree of freedom of extension and retraction of the curved cylinder 260 along the longitudinal extension direction of the robotic arm 250, and the calibration of the degree of freedom of rotation of the curved cylinder 260 along the longitudinal extension direction of the robotic arm 250.

[0056] In this embodiment, the laser column 1253 can be disposed on the side wall of the curved cylinder 260, and the laser column 1253 can emit a laser 12531 perpendicular to the extension and retraction direction of the curved cylinder 260. The scale line 1255 on the transparent plate 1254 is arranged in a direction perpendicular to the third calibration arm 113 and the fourth calibration arm 114. Since the extension and retraction direction of the curved cylinder 260 is parallel to the extension direction of the longitudinal robotic arm 250, when the laser column 1253 contacts the end of the fourth calibration arm 114 away from the third calibration arm 113, the curved cylinder 260 can be considered to be at zero position in the extension direction of the longitudinal robotic arm 250, that is, the calibration of the extension and retraction degree of freedom of the curved cylinder 260 in the extension direction of the longitudinal robotic arm 250 is completed. When the laser column 1253 contacts the end of the fourth calibration arm 114 away from the third calibration arm 113, the contact of the fourth calibration arm 114 can restrict the continued extension and retraction of the curved cylinder 260. Furthermore, since at least two transparent plates 1254 are spaced apart along the extension direction of the fourth calibration arm 114, and the extension direction of the fourth calibration arm 114 is in the same plane as the beam direction of the laser 12531, when the curved cylinder 260 rotates to a certain angle, the laser 12531 can simultaneously irradiate the same scale on at least two transparent plates 1254. This indicates that the beam direction of the laser 12531 is parallel to the extension direction of the fourth calibration arm 114, and the degree of freedom of the curved cylinder 260 to rotate along the extension direction of the longitudinal robotic arm 250 can be considered to be zero, thus completing the calibration of the degree of freedom of the curved cylinder 260 to rotate along the extension direction of the longitudinal robotic arm 250.

[0057] In some embodiments, the third calibration arm 113 may be moved relative to the fourth calibration arm 114 along the extension direction of the fourth calibration arm 114 to adjust the position of the third calibration arm 113 in the extension direction of the fourth calibration arm 114 based on the cross-sectional area of ​​the curved cylinder 260 along the extension direction of the longitudinal robotic arm 250 and the cross-sectional area of ​​the longitudinal robotic arm 250 along its own extension direction, so that when the fourth calibration arm 114 abuts against the curved cylinder 260, the longitudinal robotic arm 250 is parallel to the third calibration arm 113. For example, when the ratio of the cross-sectional area of ​​the curved cylinder 260 along the extension direction of the longitudinal robotic arm 250 to the cross-sectional area of ​​the longitudinal robotic arm 250 along its own extension direction is small, the third calibration arm 113 may be controlled to move away from the curved cylinder 260 along the extension direction of the fourth calibration arm 114. In some embodiments, the robotic arm calibration device 100 further includes a second distance adjustment device (not shown), which is configured to adjust the movement distance of the third calibration arm 113 in the extension direction of the fourth calibration arm 114.

[0058] In some embodiments, the fourth calibration arm 114 can move relative to the third calibration arm 113 along the extension direction of the third calibration arm 113, so that the fourth calibration arm 114 can abut against the curved cylinder 260 when calibrating the robotic arm 200 of the longitudinal robotic arm 250 of different lengths. In some embodiments, the second distance adjustment device can also be configured to adjust the movement distance of the fourth calibration arm 114 in the extension direction of the third calibration arm 113. In some embodiments, the specific structure of the second distance adjustment device can be the same as or similar to the specific structure of the first distance adjustment device.

[0059] In some embodiments, after the third calibration arm 113 and the fourth calibration arm 114 are connected, the relative positions of the fourth calibration arm 114 and the third calibration arm 113 are fixed, that is, the fourth calibration arm 114 and the third calibration arm 113 cannot move relative to each other.

[0060] In some embodiments, the second calibration arm 112, the third calibration arm 113, and the fourth calibration arm 114 can be considered to be located in the same plane. Since the first calibration arm 111 and the base coordinate disk 210 may have assembly errors (or calibration errors) during installation and fixing, the first transverse robotic arm 220 may deviate from the plane where the second calibration arm 112, the third calibration arm 113, and the fourth calibration arm 114 are located. This assembly error can be determined by the laser 12531 emitted by the laser column 1253. As an example only, the centerline of the third calibration arm 113 can be considered to be in the same plane as the second calibration arm 112, the third calibration arm 113 and the fourth calibration arm 114, and the beam direction of the laser 12531 can be considered to be in the same plane as the first transverse robotic arm 220, and this plane is parallel to the plane where the second calibration arm 112, the third calibration arm 113 and the fourth calibration arm 114 are located. Therefore, when the laser 12531 irradiates the same scale on at least two transparent plates 1254, the distance between the scale irradiated by the laser 12531 and the centerline of the third calibration arm 113 is the assembly error k (i.e., the distance between the plane where the second calibration arm 112, the third calibration arm 113 and the fourth calibration arm 114 are located and the plane where the first transverse robotic arm 220 and the beam direction of the laser 12531 are located). The centerline of the third calibration arm 113 can be a scale set on the outer wall of the third calibration arm 113. This centerline is set along the extending direction of the third calibration arm 113 and can be respectively set on the two side walls of the transparent plate 1254 on the third calibration arm 113, with the side walls of the third calibration arm 113 being symmetrical with respect to the centerline. The bottom end of the centerline of the third calibration arm 113 is connected to the scale line 1255. In some embodiments, the assembly error k can be used to compensate for the calibration accuracy of the robotic arm 200, so that the calibration accuracy of the robotic arm calibration device 100 is relatively controllable. For example, the value of the assembly error k can be input into the control algorithm related to the robotic arm 200.

[0061] In some embodiments, the robotic arm calibration device 100 provided in the embodiments of this specification is based on... Figures 2-3The calibration steps for the shown robotic arm 200 may include: fixing the first calibration arm 111 to the base coordinate disk 210 of the robotic arm 200; rotating the longitudinal robotic arm 250 so that the second plunger 1251 abuts against the blocking member 1252 to calibrate the rotational degree of freedom of the first transverse robotic arm 220; continuing to move the longitudinal robotic arm 250 so that the side wall of the curved cylinder 260 abuts against the end of the fourth calibration arm 114 away from the third calibration arm 113, thereby making the longitudinal robotic arm 250 parallel to the third calibration arm 113 to calibrate the distance of the longitudinal robotic arm 250; controlling the curved cylinder 260 to extend and retract so that the curved cylinder 260 The laser column 1253 on the side wall abuts against the fourth calibration arm 114 to calibrate the extension and retraction degrees of freedom of the curved cylinder 260; the curved cylinder 260 is controlled to rotate so that the laser 12531 simultaneously illuminates the same scale on at least two transparent plates 1254 to calibrate the rotational degrees of freedom of the curved cylinder 260; based on the distance between the scale illuminated by the laser 12531 and the center line of the scale line 1255, the assembly error k generated by the assembly of the robotic arm calibration device 100 and the robotic arm 200 is determined; the assembly error k is input into the control algorithm related to the robotic arm 200 to compensate for the calibration parameters of the robotic arm 200 and improve the calibration accuracy.

[0062] The beneficial effects of the robotic arm calibration device provided in this manual include, but are not limited to: (1) Since the robotic arm calibration device calibrates the robotic arm through calibration arms and positioning components, the overall structure of the robotic arm calibration device is relatively simple, the manufacturing cost is low, and it is suitable for large-scale production in the workshop; (2) When using this robotic arm calibration device to calibrate the robotic arm, fewer steps are required, and it is simpler and more convenient. That is, the relative positions between multiple calibration arms and the robotic arm are fixed by using positioning components. Therefore, the final error only includes the assembly error when the robotic arm and the robotic arm calibration device are relatively fixed. This assembly error is input into After being incorporated into the control algorithm of the robotic arm, the calibration parameters of the robotic arm can be compensated, the calibration accuracy is relatively controllable, and the calibration accuracy is high; (3) By configuring the third calibration arm to be able to move relative to the second calibration arm along the extension direction of the second calibration arm, the distance between the third calibration arm and the rotation axis of the second calibration arm and the first calibration arm can be adjusted according to the different distance calibration requirements of the longitudinal robotic arm, so as to adapt to more calibration scenarios; (4) By configuring the fourth calibration arm to be able to move relative to the third calibration arm along the extension direction of the third calibration arm, the fourth calibration arm can be able to contact the bending cylinder in scenarios applied to longitudinal machines of different lengths.

[0063] The above description is merely a preferred embodiment of this specification and is not intended to limit this specification. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this specification should be included within the scope of protection of this specification.

Claims

1. A robot arm calibration device, characterized by, It includes multiple calibration arms and a positioning component. The multiple calibration arms are movably connected in sequence. The relative positions of the multiple calibration arms and the relative positions of the multiple calibration arms and the robotic arm are fixed by the positioning component. The included angle between at least two adjacent connected calibration arms is set at a first angle. The plurality of calibration arms includes at least a first calibration arm and a second calibration arm, wherein the first calibration arm and the second calibration arm are rotatably connected; The positioning component includes a first positioning element; when the first positioning element is simultaneously connected to the first calibration arm and the second calibration arm, the included angle between the first calibration arm and the second calibration arm is fixed; when the first positioning element is not simultaneously connected to the first calibration arm and the second calibration arm, the first calibration arm and the second calibration arm can rotate relative to each other. The second calibration arm includes multiple mounting positions, and the first calibration arm is rotatably connected to one of the multiple mounting positions.

2. The apparatus of claim 1, wherein, The first positioning element includes a first plunger; the first calibration arm is connected to one of the plurality of mounting positions via at least one of the first plungers.

3. The apparatus of claim 1, wherein, The plurality of calibration arms further includes a third calibration arm and a fourth calibration arm, wherein the second calibration arm and the third calibration arm are movably connected, and the third calibration arm and the fourth calibration arm are movably connected; the positioning assembly further includes a second positioning element, wherein the relative positions of the second calibration arm, the third calibration arm and the fourth calibration arm with respect to the robotic arm are all fixed by the second positioning element.

4. The apparatus of claim 3, wherein, The angle between the second calibration arm and the third calibration arm is 90 degrees, and / or the angle between the third calibration arm and the fourth calibration arm is 90 degrees.

5. The robotic arm calibration device according to claim 3, characterized in that, It also includes a first distance adjustment device, which is configured to adjust the movement distance of the second calibration arm in the extension direction of the third calibration arm, and / or the first distance adjustment device is configured to adjust the movement distance of the third calibration arm in the extension direction of the second calibration arm.

6. The robotic arm calibration device according to claim 3, characterized in that, It also includes a second distance adjustment device, which is configured to adjust the movement distance of the third calibration arm in the extension direction of the fourth calibration arm, and / or the second distance adjustment device is configured to adjust the movement distance of the fourth calibration arm in the extension direction of the third calibration arm.

7. The robotic arm calibration device according to claim 3, characterized in that, The second positioning element includes a second plunger, the extension direction of which is parallel to the extension direction of the second calibration arm. When the second plunger connects the third calibration arm and the robotic arm, and the end of the fourth calibration arm away from the third calibration arm abuts against the robotic arm, the relative positions of the second calibration arm and the third calibration arm with respect to the robotic arm are fixed.

8. The robotic arm calibration device according to claim 3, characterized in that, The second positioning element also includes: A laser beam, which is mounted on the robotic arm, is capable of emitting laser light. At least two transparent plates are disposed at the end of the third calibration arm away from the second calibration arm, the at least two transparent plates are spaced apart along the extension direction of the fourth calibration arm, and the at least two transparent plates are provided with scale lines; When the laser emitted by the laser beam illuminates the same scale on the at least two transparent plates along the extension direction of the fourth calibration arm, the relative position of the fourth calibration arm and the robotic arm is fixed.

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