Robot tool coordinate system calibration method, device, equipment and storage medium

Abstract

The application discloses a kind of robot tool coordinate system calibration method, device, equipment and storage medium, belong to robot application technical field.The method comprises: determining the first distance relationship formula of the first distance of the origin position change of the tool coordinate system when end effector moves from first position to second position is mapped under the robot base coordinate system;Determine the second distance relationship formula of the second distance of the position change of the center point of pneumatic gripper when end effector moves from the first position to the second position is mapped under the camera coordinate system;According to the equal relationship of the first distance relationship formula and the second distance relationship formula, determine at least two sets of pose data of the tool center point of the end effector according to the set base point;According to the at least two sets of pose data, the origin of the tool coordinate system is calibrated.The above technical scheme realizes the quick calibration of robot tool coordinate system.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of robot application, and in particular to a robot tool coordinate system calibration method, device, equipment and storage medium. BACKGROUND

[0002] Industrial robots complete various work tasks by installing different operating tools at the end, and the accuracy of tool center point (TCP) geometry parameters directly affects the precision of robot operating trajectories. Without an accurate tool coordinate system, even a high-precision industrial robot cannot achieve a robot offline programming task with extremely high trajectory errors. At the same time, considering the high flexibility of the robot system in actual production processes, the actuating mechanism (such as various specifications of tools) is frequently replaced to improve compatibility, so the robot TCP calibration system must have multi-dimensional, multi-platform adaptability and rapid deployment in the production site while meeting the accuracy requirements.

[0003] The traditional four-point method is affected by the level of the operator, and there is a large difference in the robot TCP calibration result, and the consistency is poor. In addition, based on laser tracker calibration, the calibration process is complex, and the laser tracker is expensive, which cannot be integrated and applied to general industrial robot application scenarios. SUMMARY

[0004] The present application provides a robot tool coordinate system calibration method, device, equipment and storage medium to realize the rapid automatic calibration of the origin of the tool coordinate system of the industrial robot.

[0005] In a first aspect, an embodiment of the present application provides a robot tool coordinate system calibration method, which comprises:

[0006] According to the relationship among the robot base coordinate system, the end connecting rod coordinate system, and the tool coordinate system, a first distance relationship formula of a first distance of a position change of an origin of the tool coordinate system when an end effector moves from a first position to a second position is determined under the robot base coordinate system;

[0007] A camera is controlled to capture calibration images of a pneumatic gripper when the end effector moves from the first position to the second position, and a second distance relationship formula of a second distance of a position change of a center point of the pneumatic gripper when the end effector moves from the first position to the second position is determined under the camera coordinate system according to the calibration images and the camera extrinsic parameters; the pneumatic gripper is installed on the end effector;

[0008] At least two sets of pose data of a tool center point of the end effector are determined according to a set base point and an equal relationship of the first distance relationship formula and the second distance relationship formula.

[0009] According to the at least two groups of pose data, the origin of the tool coordinate system is calibrated.

[0010] In a second aspect, an embodiment of the present application further provides a robot tool coordinate system calibration device, which comprises:

[0011] A first relationship determining module is configured to determine, according to a relationship among a robot base coordinate system, an end connecting rod coordinate system and a tool coordinate system, a first distance relationship of a first distance of a position change of an origin of the tool coordinate system when an end effector moves from a first position to a second position, which is mapped in the robot base coordinate system.

[0012] A second relationship determining module is configured to control a camera to respectively capture calibration images of a pneumatic gripper when the end effector moves from the first position to the second position, and determine, according to the calibration images and camera extrinsic parameters, a second distance relationship of a second distance of a position change of a center point of the pneumatic gripper when the end effector moves from the first position to the second position, which is mapped in a camera coordinate system; the pneumatic gripper is installed on the end effector.

[0013] A pose data determining module is configured to determine at least two groups of pose data of a tool center point of the end effector according to a set base point and an equal relationship of the first distance relationship and the second distance relationship.

[0014] An origin calibration module is configured to calibrate the origin of the tool coordinate system according to the at least two groups of pose data.

[0015] In a third aspect, an embodiment of the present application further provides an electronic device, which comprises:

[0016] One or more processors;

[0017] A memory configured to store one or more programs;

[0018] When the one or more programs are executed by the one or more processors, the one or more processors are caused to implement the robot tool coordinate system calibration method provided by any embodiment of the present application.

[0019] In a fourth aspect, an embodiment of the present application further provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to implement the robot tool coordinate system calibration method provided by any embodiment of the present application.

[0020] The technical scheme of the embodiment of the present application determines a first distance relationship formula of a first distance of a position change of an origin of a tool coordinate system when an end effector moves from a first position to a second position, according to the relationship among a robot base coordinate system, a terminal connecting rod coordinate system, and the tool coordinate system, and then controls a camera to capture calibration images of a pneumatic gripper when the end effector moves from the first position to the second position, and determines a second distance relationship formula of a second distance of a position change of a center point of the pneumatic gripper when the end effector moves from the first position to the second position, according to the calibration images and camera external parameters; the pneumatic gripper is installed on the end effector, and then at least two sets of pose data of a tool center point of the end effector are determined according to a set base point and the equal relationship of the first distance relationship formula and the second distance relationship formula, and finally the origin of the tool coordinate system is calibrated according to the at least two sets of pose data. The above technical scheme realizes the origin calibration of the tool coordinate system by means of the calibration images captured by the visual camera and the distance constraint, realizes the rapid calibration of the origin of the tool coordinate system of the robot, and provides a new idea for the calibration of the tool coordinate system of the robot. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a flowchart of a robot tool coordinate system calibration method provided by an embodiment of the present application;

[0022] Figure 2 is a flowchart of a robot tool coordinate system calibration method provided by an embodiment of the present application;

[0023] Figure 3A is a flowchart of a robot tool coordinate system calibration method provided by an embodiment of the present application;

[0024] Figure 3B is a schematic diagram of a robot calibration process provided by an embodiment of the present application;

[0025] Figure 4 is a structural schematic diagram of a robot tool coordinate system calibration method provided by an embodiment of the present application;

[0026] Figure 5 is a structural schematic diagram of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0027] The present application will be further described below in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present application, and not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, not all the structures.

[0028] Embodiment One

[0029] Figure 1 is a flowchart of a robot tool coordinate system calibration method provided by an embodiment of the present application. The embodiment can be applied to the calibration of a robot tool coordinate system. The method can be executed by a robot tool coordinate system calibration device. The device can be implemented in software and / or hardware, and can be integrated into an electronic device that supports the calibration function of a robot tool coordinate system, such as a robot controller. Optionally, an end effector can be fixed on the end flange of the robot, and different work tools can be installed on the end effector.

[0030] As shown in Figure 1 , the device can specifically include:

[0031] S110, according to the relationship among the robot base coordinate system, the end connecting rod coordinate system, and the tool coordinate system, determining a first distance relationship of a first distance of a change in the position of the origin of the tool coordinate system when the end effector moves from a first position to a second position, mapped in the robot base coordinate system.

[0032] In this embodiment, the robot base coordinate system refers to a coordinate system constructed with the center of the robot as the origin; the end connecting rod coordinate system refers to a coordinate system constructed with the center of the end effector as the origin; and the tool coordinate system refers to a coordinate system constructed with the tool center point as the origin.

[0033] Optionally, the pose of the end effector can be controlled to change, i.e., to move from the first position to the second position. Then, according to the conversion relationship among the robot base coordinate system, the end connecting rod coordinate system, and the tool coordinate system, the origin of the tool coordinate system can be constructed. After that, the first coordinate of the origin of the tool coordinate system in the robot base coordinate system when the end effector is at the first position, and the second coordinate of the origin of the tool coordinate system in the robot base coordinate system when the end effector is at the second position can be determined. Then, according to the first coordinate and the second coordinate, the first distance relationship of the first distance of the change in the position of the origin of the tool coordinate system when the end effector moves from the first position to the second position, mapped in the robot base coordinate system can be determined.

[0034] Alternatively, the origin point feature representation of the tool coordinate system in the robot base coordinate system can be determined according to a relationship among a first homogeneous transformation matrix of the tool coordinate system relative to the robot base coordinate system, a second homogeneous transformation matrix of the tool coordinate system relative to the end connecting rod coordinate system, and a third homogeneous transformation matrix of the end connecting rod coordinate system relative to the robot base coordinate system, and then a first feature representation of the origin point feature representation when the end effector is located at the first position and a second feature representation of the origin point feature representation when the end effector is located at the second position are determined, and then a first distance relationship of a distance of a position change of the origin point of the tool coordinate system when the end effector moves from the first position to the second position mapped in the robot base coordinate system is determined according to the first feature representation and the second feature representation.

[0035] wherein the homogeneous transformation matrix is composed of a rotation matrix and a translation matrix, the pose state is contained in the rotation matrix, and the position coordinates are contained in the translation matrix.

[0036] Specifically, first, the origin point feature representation of the tool coordinate system in the robot base coordinate system is defined according to a relationship among a first homogeneous transformation matrix of the tool coordinate system relative to the robot base coordinate system, a second homogeneous transformation matrix of the tool coordinate system relative to the end connecting rod coordinate system, and a third homogeneous transformation matrix of the end connecting rod coordinate system relative to the robot base coordinate system, i.e., the first homogeneous transformation matrix is equal to a product of the third homogeneous transformation matrix and the second homogeneous transformation matrix, and the origin point feature representation of the tool coordinate system in the robot base coordinate system can be determined, for example, by the following formula:

[0037]

[0038]

[0039] Combining the formula (1) and the formula (2), the following formula (3) can be obtained:

[0040]

[0041] wherein, represents the first homogeneous transformation matrix of the tool coordinate system relative to the robot base coordinate system, represents the first rotation matrix of the tool coordinate system relative to the robot base coordinate system, represents the first translation matrix of the tool coordinate system relative to the robot base coordinate system; represents the third homogeneous transformation matrix of the end connecting rod coordinate system relative to the robot base coordinate system, represents the third rotation matrix of the end connecting rod coordinate system relative to the robot base coordinate system, represents the third translation matrix of the end connecting rod coordinate system relative to the robot base coordinate system; a second homogeneous transformation matrix representing the tool coordinate system with respect to the end link coordinate system, a second rotation matrix representing the tool coordinate system with respect to the end link coordinate system, a second translation matrix representing the tool coordinate system with respect to the end link coordinate system. In formula (3) is the origin feature representation of the origin of the tool coordinate system under the origin of the robot base coordinate system.

[0042] After determining the origin feature representation of the origin of the tool coordinate system under the origin of the robot base coordinate system, the end effector is controlled to move to the first position and the second position respectively, the first feature representation of the origin feature representation when the end effector is located at the first position and the second feature representation of the origin feature representation when the end effector is located at the second position can be obtained, as follows:

[0043]

[0044] wherein, the first feature representation of the origin feature representation when the end effector is located at the first position, the second feature representation of the origin feature representation when the end effector is located at the second position, a third rotation matrix representing the end link coordinate system with respect to the robot base coordinate system when the end effector is located at the first position, a second translation matrix representing the tool coordinate system with respect to the end link coordinate system when the end effector is located at the first position, a third translation matrix representing the end link coordinate system with respect to the robot base coordinate system; a third rotation matrix representing the end link coordinate system with respect to the robot base coordinate system when the end effector is located at the second position, a second translation matrix representing the tool coordinate system with respect to the end link coordinate system when the end effector is located at the second position, a third translation matrix representing the end link coordinate system with respect to the robot base coordinate system.

[0045] Further, according to the first feature representation and the second feature representation, a first distance relationship of the distance of the position change of the origin of the tool coordinate system when the end effector moves from the first position to the second position mapped under the robot base coordinate system is determined, for example, which can be obtained by the following formula:

[0046]

[0047] wherein, is known, unknown, i.e. the pose (position and attitude) of the tool center point of the end effector.

[0048] S120, control the camera to respectively shoot the calibration image of the pneumatic gripper when the end effector moves from the first position to the second position, and determine the second distance relationship that the position change of the center point of the pneumatic gripper when the end effector moves from the first position to the second position is mapped in the second distance under the camera coordinate system according to the calibration image and the camera extrinsic parameter.

[0049] In the embodiment, the pneumatic gripper is installed on the end effector. The camera is fixed outside the robot, and the camera can shoot the calibration image containing the pneumatic gripper.

[0050] In the embodiment, the camera can be controlled to respectively shoot the calibration image of the pneumatic gripper when the end effector moves from the first position to the second position. The calibration image refers to the image shot by the camera after the pneumatic gripper is projected to the calibration board.

[0051] Optionally, the image coordinates of the center point of the pneumatic gripper can be obtained according to the shot calibration image of the pneumatic gripper; the calibration coordinates of the center point of the pneumatic gripper in the calibration coordinate system can be determined according to the image coordinates and the perspective transformation between the calibration board coordinate system and the image coordinate system; the camera coordinates of the center point of the pneumatic gripper in the camera coordinate system can be determined according to the calibration coordinates and the camera extrinsic parameter; and the second distance relationship that the position change of the pneumatic gripper when the end effector moves from the first position to the second position is mapped in the second distance under the camera coordinate system can be determined according to the camera coordinates.

[0052] Specifically, the image coordinates of the center point of the pneumatic gripper can be obtained according to the shot calibration image of the pneumatic gripper, that is, the image coordinates of the center point of the pneumatic gripper in the first position and the second position of the end effector are obtained, which are denoted as the first image coordinates and the second image coordinates, by fitting the center of the cylinder according to the selection of the area where the pneumatic gripper is located in the calibration image and the fitting of the center.

[0053] After the image coordinates of the center point of the pneumatic gripper are determined, the calibration coordinates of the center point of the pneumatic gripper in the calibration coordinate system can be determined according to the image coordinates and the perspective transformation between the calibration board coordinate system and the image coordinate system. The perspective transformation between the calibration board coordinate system and the image coordinate system is established by the calibration coordinates of at least three key points on the calibration board in the calibration board coordinate system and the image coordinates of at least three key points on the calibration board in the image coordinate system. For example, the calibration coordinates of the center point of the pneumatic gripper in the calibration coordinate system can be determined by the following formula:

[0054]

[0055] wherein (x w , y w) is the calibration coordinate of the center point of the pneumatic gripper in the calibration coordinate system, (u, v) represents the image coordinate of the center point of the pneumatic gripper in the image coordinate system, represents the perspective transformation.

[0056] After determining the calibration coordinate of the center point of the pneumatic gripper in the calibration coordinate system, the camera coordinate of the center point of the pneumatic gripper in the camera coordinate system is determined according to the calibration coordinate and the camera extrinsic parameter. The camera extrinsic parameter is obtained by an existing method, for example, the camera extrinsic parameter can be obtained by the calibration method based on a plane template proposed by Zhang Zhengyou. Exemplarily, the camera coordinate of the center point of the pneumatic gripper in the camera coordinate system can be determined by the following formula:

[0057]

[0058] wherein, (x c , y c , z c ) represents the camera coordinate of the center point of the pneumatic gripper in the camera coordinate system, (x w , y w , 0) represents the calibration coordinate of the center point of the pneumatic gripper in the calibration coordinate system, and [r1, r2, r3, t] represents the camera extrinsic parameter.

[0059] After determining the camera coordinate of the center point of the pneumatic gripper in the camera coordinate system, the second distance relationship formula in the camera coordinate system, in which the position change of the pneumatic gripper when the end effector moves from the first position to the second position is mapped, is determined according to the camera coordinate. Specifically, when the robot is controlled to change the pose so that the end effector changes from the first position to the second position, the position of the pneumatic gripper relative to the auxiliary camera also changes from to For example, the second distance relationship formula in the camera coordinate system, in which the position change of the pneumatic gripper when the end effector moves from the first position to the second position is mapped, can be determined by the following formula:

[0060]

[0061] wherein, represents the second distance relationship formula in the camera coordinate system, in which the position change of the pneumatic gripper when the end effector moves from the first position to the second position is mapped, represents the position of the center point of the pneumatic gripper relative to the camera when the end effector is at the first position, that is, the camera coordinate of the origin of the tool coordinate system relative to the camera coordinate system when the end effector is at the first position, represents the position of the center point of the pneumatic gripper relative to the camera when the end effector is at the second position, (x a , y a , z a ) represents the camera coordinate of the origin of the tool coordinate system relative to the camera coordinate system when the end effector is at the first position, and (x b , y b , zb represents the origin of the tool coordinate system of the end effector at the second position relative to the camera coordinates of the camera coordinate system.

[0062] S130, according to the set base point, and the equal relationship of the first distance relationship and the second distance relationship, determine at least two groups of pose data of the tool center point of the end effector.

[0063] In this embodiment, the equal relationship of the first distance relationship and the second distance relationship is:

[0064]

[0065] In this embodiment, the end effector is controlled to translate to three different positions respectively, and the position points of the center points of the three pneumatic grippers are obtained, which are the first base point, the second base point and the third base point respectively; the first base point, the second base point and the third base point are combined in pairs to obtain three groups of line segment data; the first distance relationship and the second distance relationship are updated respectively by using the three groups of line segment data; based on the equal relationship of the first distance relationship and the second distance relationship, at least two groups of pose data of the tool center point of the end effector are determined according to the updated three groups of first distance relationship and three groups of second distance relationship.

[0066] Specifically, within the camera shooting range, the end effector is controlled to translate to three different positions respectively, and the position points of the center points of the three pneumatic grippers are obtained, which are the first base point, the second base point and the third base point respectively, and are recorded as respectively relative to the camera coordinate system. Then, the first base point, the second base point and the third base point are combined in pairs to obtain three groups of line segment data, which are recorded as In the camera coordinate system, they are recorded as Then, the first distance relationship and the second distance relationship are updated respectively by using the three groups of line segment data, and based on the equal relationship of the first distance relationship and the second distance relationship, at least two groups of pose data of the tool center point of the end effector are determined according to the updated three groups of first distance relationship and three groups of second distance relationship. Specifically, a three-element quadratic equation group is constructed, as follows, and at least two groups of pose data of the tool center point of the end effector can be obtained by solving the equation group, that is Unknown, which represents the pose (position and attitude) of the tool center point of the end effector.

[0067]

[0068] Wherein, (x1, y1, z1) represents the camera coordinates of the first base point in the camera coordinate system; (x2, y2, z2) represents the camera coordinates of the second base point in the camera coordinate system; (x3, y3, z3) represents the camera coordinates of the third base point in the camera coordinate system.

[0069] S140, calibrate the origin of the tool coordinate system according to the at least two sets of pose data.

[0070] In the embodiment, one set of pose data can be randomly selected from the at least two sets of pose data, and the position data in the pose data can be used to calibrate the origin of the tool coordinate system.

[0071] The technical scheme of the embodiment of the application comprises the following steps: determining, according to the relationship among the robot base coordinate system, the end connecting rod coordinate system and the tool coordinate system, a first distance relationship formula of a first distance of a position change of an origin of the tool coordinate system when an end effector moves from a first position to a second position, mapping in the robot base coordinate system; controlling a camera to capture calibration images of a pneumatic gripper when the end effector moves from the first position to the second position; determining, according to the calibration images and camera extrinsic parameters, a second distance relationship formula of a second distance of a position change of a center point of the pneumatic gripper when the end effector moves from the first position to the second position, mapping in the camera coordinate system; installing the pneumatic gripper on the end effector; determining at least two sets of pose data of a tool center point of the end effector according to a set base point and the equal relationship between the first distance relationship formula and the second distance relationship formula; and calibrating the origin of the tool coordinate system according to the at least two sets of pose data. The above technical scheme calibrates the origin of the tool coordinate system by means of the calibration images captured by the camera and the distance constraint, realizes the rapid calibration of the origin of the tool coordinate system of the robot, and provides a new idea for the calibration of the tool coordinate system of the robot.

[0072] Figure 2 is a flowchart of a robot tool coordinate system calibration method provided in the second embodiment of the application, which is further optimized on the basis of the above-mentioned embodiment and provides an optional implementation manner.

[0073] As Figure 2 indicated, the method can specifically comprise the following steps.

[0074] S210, determining, according to the relationship among the robot base coordinate system, the end connecting rod coordinate system and the tool coordinate system, a first distance relationship formula of a first distance of a position change of an origin of the tool coordinate system when an end effector moves from a first position to a second position, mapping in the robot base coordinate system.

[0075] S220, control the camera to shoot the calibration image of the pneumatic gripper when the end effector moves from the first position to the second position, and determine the second distance relationship of the position change of the center point of the pneumatic gripper when the end effector moves from the first position to the second position according to the calibration image and the camera external parameter.

[0076] The pneumatic gripper is mounted on the end effector.

[0077] S230, determine at least two sets of pose data of the tool center point of the end effector according to the set base point and the equal relationship of the first distance relationship and the second distance relationship.

[0078] S240, calibrate the origin of the tool coordinate system according to the at least two sets of pose data.

[0079] In the embodiment, the end effector of the robot can be controlled to change the pose to obtain the fourth base point of the center point of the pneumatic gripper, which is denoted as In the camera coordinate system, it is denoted as The fourth base point is combined with the first base point, the second base point and the third base point respectively to obtain three sets of verification line segment data, that is, in the robot base coordinate system In the camera coordinate system The first distance relationship and the second distance relationship are updated respectively by using the three sets of verification line segment data; and a residual expression is constructed according to the updated three sets of first distance relationship and three sets of second distance relationship, as follows:

[0080]

[0081] Wherein, δ i represents the residual of the sum of the differences between the corresponding line segments in the robot base coordinate system and the camera coordinate system under the i th set of displacement data.

[0082] Further, according to the at least two sets of pose data and the residual expression, target pose data is selected from the at least two sets of pose data; and the origin of the tool coordinate system is calibrated by using the target pose data. Specifically, the at least two sets of pose data are substituted into the residual expression to obtain at least two residual values; the pose data corresponding to the smallest residual value in the at least two residual values is taken as the target pose data, and then the origin of the tool coordinate system is calibrated by using the target pose data.

[0083] The technical scheme of the embodiment of the present application determines a first distance relationship formula of a position change of an origin of a tool coordinate system when an end effector moves from a first position to a second position, which is mapped to a first distance under a robot base coordinate system, according to the relationship among the robot base coordinate system, the end connecting rod coordinate system and the tool coordinate system, and then controls the camera to capture calibration images of the pneumatic gripper when the end effector moves from the first position to the second position, and determines a second distance relationship formula of a position change of a center point of the pneumatic gripper when the end effector moves from the first position to the second position, which is mapped to a second distance under the camera coordinate system, according to the calibration images and the camera external parameters. The pneumatic gripper is installed on the end effector, and then at least two sets of pose data of a tool center point of the end effector are determined according to the set base point and the equal relationship of the first distance relationship formula and the second distance relationship formula, and finally the origin of the tool coordinate system is calibrated according to the at least two sets of pose data. The above technical scheme realizes the origin calibration of the tool coordinate system by means of the calibration images captured by the visual camera and the distance constraint, realizes the rapid calibration of the origin of the tool coordinate system of the robot, and provides a new idea for the calibration of the tool coordinate system of the robot.

[0084] Embodiment three

[0085] Figure 3A is a flowchart of a robot tool coordinate system calibration method provided by the embodiment three of the present application, and a preferred implementation is provided on the basis of the above embodiment. Optionally, as shown in Figure 3B a schematic diagram of a robot tool coordinate system calibration process is given, and in the calibration process, a six-axis industrial robot 1-1, an end effector 1-2 of the six-axis industrial robot, a black cylinder 1-3, a machine vision calibration board 1-4, a transparent plate 1-5 and a machine vision system 1-6 are involved. The end effector 1-2 is fixed with the end flange plate of the six-axis industrial robot 1-2. The machine vision system 1-6 is installed in the reachable workspace of the six-axis industrial robot 1-1. The black cylinder 1-3 is installed at the front end of the end effector 1-2. The transparent plate 1-5 is installed in front of the black cylinder 1-3, and the machine vision calibration board 1-4 is installed on the transparent plate 1-5. The machine vision calibration board 1-4 is a circular dot calibration board with a circular pitch of 4mm and a circular radius of 1mm, and has 7 rows and 7 columns of calibration points. A tool coordinate system is established in the robot controller and named as {T}, which is used to store the calibrated tool coordinate system data. A camera coordinate system of the machine vision is established and named as {C}. In the calibration process, the industrial camera vision system 1-6 remains stationary, and the six-axis industrial robot 1-1 is manually operated to change the pose of the robot as much as possible while ensuring that the end effector 1-2 of the six-axis industrial robot is in the camera field of view and the camera can capture high-quality calibration board pictures. The above action process is repeated to obtain four sets of measurement data, i.e. image coordinates corresponding to the first base point, the second base point, the third base point and the fourth base point.

[0086] As Figure 3A shown, the method can specifically include:

[0087] S310, perspective transformation between the calibration board coordinate system and the image coordinate system is established based on formula (6), and the calibration coordinates of the center point of the pneumatic gripper in the calibration coordinate system are determined according to the image coordinates of the center point of the pneumatic gripper.

[0088] S320, based on formula (7), the camera coordinates of the center point of the pneumatic gripper in the camera coordinate system are determined according to the camera external parameters and the calibration coordinates of the center point of the pneumatic gripper in the calibration coordinate system.

[0089] S330, all pose data, i.e. 8 sets of solutions, are solved based on formula (10).

[0090] S340, based on formula (11), the real solution with the minimum residual value is found, i.e. the target pose data is found, and the origin of the tool coordinate system is calibrated.

[0091] The positions of the center points of the pneumatic gripper in the camera coordinate system in the four images obtained according to the above steps are shown in Table 1, and all the solutions, i.e. 8 sets of pose data, are shown in Table 2.

[0092] Table 1 Position of the robot end effector in the camera coordinate system

[0093]

[0094] Table 2 All solutions obtained

[0095]

[0096] According to formula (11), the residual of the first four real solutions is solved, and the result shows that the residual of the second result is the smallest, i.e. the calibration result of the industrial robot TCP is [40.584, 0.482, 250.545]. Finally, the calibration result is written into the robot controller.

[0097] Example four

[0098] Figure 4 is a structural schematic diagram of a robot tool coordinate system calibration method provided by the fourth embodiment of the present application. The present embodiment can be applicable to the situation of robot tool coordinate system calibration. The device can be realized by software and / or hardware, and can be integrated in an electronic device carrying the calibration function of the robot tool coordinate system, such as a robot controller.

[0099] As Figure 4 shown, the device can specifically include:

[0100] The first relationship determining module 410 is configured to determine a first distance relationship of a first distance of a position change of an origin of the tool coordinate system in the robot base coordinate system when the end effector moves from the first position to the second position according to a relationship among the robot base coordinate system, the end connecting rod coordinate system and the tool coordinate system.

[0101] The second relationship determining module 420 is configured to control the camera to capture calibration images of the pneumatic gripper when the end effector moves from the first position to the second position respectively, and determine a second distance relationship of a second distance of a position change of a center point of the pneumatic gripper in the camera coordinate system according to the calibration images and the camera extrinsic parameters.

[0102] The pose data determining module 430 is configured to determine at least two groups of pose data of a tool center point of the end effector according to a set base point and an equal relationship of the first distance relationship and the second distance relationship.

[0103] The origin calibrating module 440 is configured to calibrate the origin of the tool coordinate system according to the at least two groups of pose data.

[0104] The technical scheme of the embodiment of the application determines the first distance relationship of the first distance of the position change of the origin of the tool coordinate system in the robot base coordinate system when the end effector moves from the first position to the second position according to the relationship among the robot base coordinate system, the end connecting rod coordinate system and the tool coordinate system, then controls the camera to capture the calibration images of the pneumatic gripper when the end effector moves from the first position to the second position respectively, and determines the second distance relationship of the second distance of the position change of the center point of the pneumatic gripper in the camera coordinate system according to the calibration images and the camera extrinsic parameters, the pneumatic gripper is installed on the end effector, then determines the at least two groups of pose data of the tool center point of the end effector according to the set base point and the equal relationship of the first distance relationship and the second distance relationship, and finally calibrates the origin of the tool coordinate system according to the at least two groups of pose data. The above technical scheme calibrates the origin of the tool coordinate system by means of the calibration images captured by the visual camera and the distance constraint, realizes the rapid calibration of the origin of the tool coordinate system of the robot, and provides a new idea for the calibration of the tool coordinate system of the robot.

[0105] Further, the first relationship determining module 410 is specifically configured to:

[0106] The first point feature representation of the origin point feature representation when the end effector is located at the first position and the second point feature representation of the origin point feature representation when the end effector is located at the second position are determined.

[0107] The first point feature representation of the origin point feature representation when the end effector is located at the first position and the second point feature representation of the origin point feature representation when the end effector is located at the second position are determined.

[0108] According to the first point feature representation and the second point feature representation, a first distance relationship of a distance that a position change of the origin point of the tool coordinate system when the end effector moves from the first position to the second position is mapped in the robot base coordinate system is determined.

[0109] Further, the second relationship determination module 420 is specifically configured to:

[0110] According to the captured calibration image of the pneumatic gripper, an image coordinate of a center point of the pneumatic gripper is obtained;

[0111] According to the image coordinate and a perspective transformation between the calibration board coordinate system and the image coordinate system, a calibration coordinate of the center point of the pneumatic gripper in the calibration coordinate system is determined; wherein the calibration board coordinate system is a world coordinate system that is preset;

[0112] According to the calibration coordinate and the camera extrinsic parameter, a camera coordinate of the center point of the pneumatic gripper in the camera coordinate system is determined;

[0113] According to the camera coordinate, a second distance relationship that a position change of the pneumatic gripper when the end effector moves from the first position to the second position is mapped in the camera coordinate system is determined.

[0114] Further, the pose data determination module 430 is specifically configured to:

[0115] The end effector is controlled to move to three different positions respectively to obtain three position points of the center points of the three pneumatic grippers, which are a first base point, a second base point and a third base point respectively;

[0116] The first base point, the second base point and the third base point are combined in pairs to obtain three sets of line segment data;

[0117] The first distance relationship and the second distance relationship are updated respectively by using the three sets of line segment data;

[0118] Based on the equal relationship of the first distance relationship and the second distance relationship, at least two sets of pose data of the tool center point of the end effector are determined according to the updated three sets of first distance relationships and three sets of second distance relationships.

[0119] Further, the origin calibration module 440 comprises:

[0120] A fourth base point determination unit is configured to control the end effector of the robot to change the pose to obtain a fourth base point of the center point of the pneumatic gripper;

[0121] A verification data determination unit is configured to combine the fourth base point with the first base point, the second base point and the third base point respectively in pairs to obtain three groups of verification line segment data;

[0122] A relationship updating unit is configured to update the first distance relationship and the second distance relationship respectively by using the three groups of verification line segment data;

[0123] A residual expression determination unit is configured to construct a residual expression according to the three groups of updated first distance relationships and the three groups of second distance relationships;

[0124] A target pose data determination unit is configured to select target pose data from the at least two groups of pose data according to the at least two groups of pose data and the residual expression;

[0125] An origin calibration unit is configured to calibrate the origin of the tool coordinate system by using the target pose data.

[0126] Further, the target pose data determination unit is specifically configured to:

[0127] Substitute the at least two groups of pose data into the residual expression to obtain at least two residual values;

[0128] Take the pose data corresponding to the smallest residual value in the at least two residual values as the target pose data.

[0129] The calibration device of the robot tool coordinate system can execute the calibration method of the robot tool coordinate system provided by any embodiment of the present application, and has the corresponding function modules and beneficial effects of the execution method.

[0130] Embodiment five

[0131] Figure 5 is a structural schematic diagram of an electronic device provided by Embodiment five of the present application, Figure 5 shows a block diagram of an exemplary device suitable for implementing embodiments of the present application. Figure 5 The device shown is merely an example and should not impose any limitation on the functions and use range of the embodiments of the present application.

[0132] As Figure 5As shown, the electronic device 12 is in the form of a general- purpose computer. The components of the electronic device 12 can include, but are not limited to, one or more processors or processing units 16, a system memory 28, and a bus 18 that couples various system components including the system memory 28 to the processing unit 16.

[0133] The bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, a graphics bus (e.g., an Accelerated Graphics Port, or AGP bus) and a processor or local bus using any of a variety of bus architectures. By way of example, these architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.

[0134] The electronic device 12 typically includes a variety of computer system readable media. Such media can be any available media that is located either internally or externally to the electronic device 12, including both volatile and nonvolatile media, removable and non-removable media.

[0135] The system memory 28 can include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. The electronic device 12 can further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, a storage system 34 can be provided for reading from and writing to non-removable, non-volatile magnetic media (e.g., a "hard drive"). Figure 5 Not shown, a removable / non-removable interface can also be provided and can include at least one drive ultra / interfacing bus 18 and a drive or memory including a non-removable, non-volatile media drive such as a media DVD ROM, DVD-RW, DVD+RW, CD ROM, etc. In these instances, the system memory 28 can also include at least one program product having a set (e.g., at least one) of program modules that are configured to carry out the functions of embodiments of the application. Figure 5 As stated above, a number of program modules and data files can be stored in the system memory 28. While executing on the processing unit 16, the program modules 42 (i.e., program / utility) 40 can perform processes including, for example, one or more applications, one or more program modules, and program data, e.g., such as an operating system 41, measurement programs, and other various program modules, programs, and program segments. The operating system 41, for example, can be any operating system as is known to those of skill in the art to include any of the Windows® operating systems (e.g., Windows® 95, Windows® 98, Windows® 2000, Windows® XP, Windows® Vista, Windows® 7, Windows® 8, Windows® 10, and the like) by Microsoft Corporation of Redmond, Washington, the different releases of the Unix® and Linux® operating systems by various vendors, the

[0136] A user can enter commands and information into the electronic device 12 through one or more wire / wireless input devices 44, such as a keyboard, touchscreen, and the like. These and other input devices 44 can be connected to the processing unit 16 through the user input interface 46 that is coupled to the bus 18, bus 18, and bus interface bus 38. A monitor or other display device 48 can also be connected to the bus 18 via an interface, such as a video interface 50. In addition to the monitor 48, the electronic device 12 can include other peripheral output devices (not shown) such as speakers and printers.

[0137] The electronic device 12 can also communicate with one or more external devices 14 such as a keyboard, a pointing device, a display 24, etc.; and moreover with one or more devices that enable a user to interact with the electronic device 12 and / or any devices (e.g., a networking card, a modem, etc.) that enable the electronic device 12 to communicate with one or more other computing devices. Such communication can occur via the input / output (I / O) interface 22. Still yet, the electronic device 12 can communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or the public network, such as the Internet) through a network adapter 20. As depicted, the network adapter 20 communicates with the other components of the electronic device 12 through the bus 18. It should be appreciated that although not shown, other hardware and / or software modules could be used in connection with the electronic device 12. Such modules include, but are not limited to, microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data archival storage systems, etc.

[0138] The processing unit 16 performs various function applications and data processing by running programs stored in the system memory 28, such as implementing the method for calibrating a robot tool coordinate system according to embodiments of the present application.

[0139] Embodiment six

[0140] Embodiment six of the present application also provides a computer readable storage medium, which stores a computer program (or computer executable instructions) for executing the method for calibrating a robot tool coordinate system according to embodiments of the present application when executed by a processor, and the method comprises:

[0141] According to the relationship among the robot base coordinate system, the end connecting rod coordinate system, and the tool coordinate system, a first distance relationship formula of a first distance of a position change of an origin of the tool coordinate system when the end effector moves from a first position to a second position is determined under a mapping in the robot base coordinate system;

[0142] A camera is controlled to respectively capture calibration images of the pneumatic gripper when the end effector moves from the first position to the second position, and a second distance relationship formula of a second distance of a position change of a center point of the pneumatic gripper when the end effector moves from the first position to the second position is determined under a mapping in the camera coordinate system according to the calibration images and the camera extrinsic parameters; the pneumatic gripper is installed on the end effector;

[0143] According to the set base point, and the equal relationship of the first distance relationship formula and the second distance relationship formula, at least two sets of pose data of a tool center point of the end effector are determined;

[0144] According to the at least two sets of pose data, the origin of the tool coordinate system is calibrated.

[0145] The computer storage medium of the embodiments of the present application can adopt any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium may, for example, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or apparatus, or any combination thereof. More specific examples (non-exhaustive list) of the computer-readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this document, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus, or device.

[0146] The computer-readable signal medium can include a data signal propagated in baseband or propagated as a carrier wave, in which computer-readable program code is embodied. Such propagated data signals can take a wide variety of forms, including but not limited to electro-magnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media can also be any computer-readable medium that is not a storage medium, that is, that is not a tangible medium, and that can communicate, propagate or transport programming for use by or in connection with an instruction execution system, apparatus, or device.

[0147] The program code embodied on the computer-readable media can be transmitted using any appropriate medium, including but not limited to wireless, wired, optical fiber cable, RF, etc., or any suitable combination of the above.

[0148] Computer program code for carrying out operations of the embodiments of the present application can be written in any combination of one or more programming languages, including an object-oriented programming language such as Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the "C" programming language, or the like. The program code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, application specific circuitry, or field programmable gate array (FPGA) circuitry can execute the program code. In some embodiments, multiple processors or multiple cores can execute the program code.

[0149] Note that the above merely describes preferred embodiments of the present application and the applied technical principles. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, modifications and substitutions can be made by those skilled in the art without departing from the scope of the present application. Therefore, although the embodiments of the present application are described in detail through the above embodiments, the embodiments of the present application are not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the claims.

Claims

1. A method of calibrating a robot tool coordinate system, characterized by, The method comprises the following steps: determining a first distance relationship of a first distance of a position change of an origin of a tool coordinate system when an end effector moves from a first position to a second position, according to a relationship among a robot base coordinate system, an end connecting rod coordinate system, and the tool coordinate system; controlling a camera to capture calibration images of a pneumatic gripper when the end effector moves from the first position to the second position, and determining a second distance relationship of a second distance of a position change of a center point of the pneumatic gripper when the end effector moves from the first position to the second position, according to the calibration images and camera extrinsic parameters, wherein the pneumatic gripper is installed on the end effector; determining at least two sets of pose data of a tool center point of the end effector, according to a set base point and an equal relationship of the first distance relationship and the second distance relationship; calibrating the origin of the tool coordinate system according to the at least two sets of pose data.

2. The method of claim 1, wherein, The method of determining the first distance relationship of the first distance of the position change of the origin of the tool coordinate system when the end effector moves from the first position to the second position, according to the relationship among the robot base coordinate system, the end connecting rod coordinate system, and the tool coordinate system, comprises the following steps: determining an origin feature representation of the origin of the tool coordinate system in the robot base coordinate system, according to a relationship among a first homogeneous transformation matrix of the tool coordinate system relative to the robot base coordinate system, a second homogeneous transformation matrix of the tool coordinate system relative to the end connecting rod coordinate system, and a third homogeneous transformation matrix of the end connecting rod coordinate system relative to the robot base coordinate system; determining a first feature representation of the origin feature representation when the end effector is at the first position, and a second feature representation of the origin feature representation when the end effector is at the second position; determining the first distance relationship of the distance of the position change of the origin of the tool coordinate system when the end effector moves from the first position to the second position in the robot base coordinate system, according to the first feature representation and the second feature representation.

3. The method of claim 1, wherein, The method of determining the second distance relationship of the second distance of the position change of the center point of the pneumatic gripper when the end effector moves from the first position to the second position in the camera coordinate system, according to the calibration images and the camera extrinsic parameters, comprises the following steps: obtaining image coordinates of the center point of the pneumatic gripper according to the captured calibration images of the pneumatic gripper; determining calibration coordinates of the center point of the pneumatic gripper in a calibration coordinate system according to the image coordinates and a perspective transformation between a calibration board coordinate system and an image coordinate system, wherein the calibration board coordinate system is a pre-set world coordinate system; determining camera coordinates of the center point of the pneumatic gripper in the camera coordinate system according to the calibration coordinates and the camera extrinsic parameters; determining the second distance relationship of the position change of the pneumatic gripper in the camera coordinate system according to the camera coordinates.

4. The method of claim 1, wherein, The method comprises the following steps: Respectively controlling the end effector to translate to three different positions to obtain three position points of the center point of the pneumatic gripper, which are a first base point, a second base point and a third base point respectively; Combining the first base point, the second base point and the third base point in pairs to obtain three sets of line segment data; Respectively updating the first distance relationship and the second distance relationship by using the three sets of line segment data; Based on the equal relationship between the first distance relationship and the second distance relationship, determining at least two sets of pose data of the tool center point of the end effector according to the updated three sets of first distance relationships and three sets of second distance relationships.

5. The method of claim 4, wherein, The method comprises the following steps: Controlling the end effector of the robot to change the pose to obtain a fourth base point of the center point of the pneumatic gripper; Combining the fourth base point with the first base point, the second base point and the third base point in pairs to obtain three sets of verification line segment data; Respectively updating the first distance relationship and the second distance relationship by using the three sets of verification line segment data; Constructing a residual expression according to the updated three sets of first distance relationships and three sets of second distance relationships; Selecting target pose data from the at least two sets of pose data according to the at least two sets of pose data and the residual expression; Using the target pose data to calibrate the origin of the tool coordinate system.

6. The method of claim 5, wherein, The method comprises the following steps: Substituting the at least two sets of pose data into the residual expression to obtain at least two residual values; Taking the pose data corresponding to the smallest residual value in the at least two residual values as the target pose data.

7. A robot tool coordinate system calibration apparatus, characterized by, The method comprises the following steps: A first relationship determining module is configured to determine a first distance relationship of a first distance of a position change of an origin of a tool coordinate system mapped in a robot base coordinate system according to relationships among the robot base coordinate system, an end connecting rod coordinate system and the tool coordinate system when an end effector moves from a first position to a second position; A second relationship determining module is configured to control a camera to respectively capture calibration images of a pneumatic gripper when the end effector moves from the first position to the second position, and determine a second distance relationship of a second distance of a position change of a center point of the pneumatic gripper mapped in a camera coordinate system according to the calibration images and camera extrinsic parameters; the pneumatic gripper is installed on the end effector; A pose data determining module is configured to determine at least two sets of pose data of a tool center point of the end effector according to a set base point and an equal relationship between the first distance relationship and the second distance relationship; An origin calibrating module is configured to calibrate the origin of the tool coordinate system according to the at least two sets of pose data.

8. The apparatus of claim 7, wherein, The first relationship determining module is specifically used for: determining, according to a first homogeneous transformation matrix of a tool coordinate system relative to a robot base coordinate system, a second homogeneous transformation matrix of the tool coordinate system relative to an end connecting rod coordinate system, and a third homogeneous transformation matrix of the end connecting rod coordinate system relative to the robot base coordinate system, a relationship among the three, a point feature representation of an origin of the tool coordinate system under an origin of the robot base coordinate system; determining a first feature representation of the point feature representation when the end effector is located at a first position, and a second feature representation of the point feature representation when the end effector is located at a second position; determining, according to the first feature representation and the second feature representation, a first distance relationship of a distance that a position change of the origin of the tool coordinate system is mapped when the end effector moves from the first position to the second position under the distance under the robot base coordinate system.

9. An electronic device, comprising: comprise: one or more processors; a memory for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the robot tool coordinate system calibration method of any one of claims 1-6.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the robot tool coordinate system calibration method of any one of claims 1-6.

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