Workpiece coordinate system calibration device and method for industrial robot, and industrial robot

Abstract

The application provides a workpiece coordinate system calibration device of an industrial robot, comprising a camera module and a coordinate system marker module; the coordinate system marker module comprises two marker points on a first straight line and two marker points on a second straight line; the camera module is used for collecting an image of the coordinate system marker module, identifying the marker points in the image, determining the coordinates of the marker points in a camera coordinate system respectively, and determining the coordinates of the intersection of the first straight line and the second straight line in the camera coordinate system; according to the conversion relationship between the camera coordinate system and a base coordinate system, the camera module is used for determining the slope k x of the first straight line relative to the x-axis of the base coordinate system, the slope k y of the second straight line relative to the x-axis of the base coordinate system, and the coordinates of the intersection in the base coordinate system respectively, and determining the workpiece coordinate system through the intersection coordinates, the slope k x and the slope k y . The application can realize the automation operation of the workpiece coordinate system calibration, and the calibration position is more accurate and the calibration time is greatly shortened compared with manual calibration.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of robots, in particular, to a workpiece coordinate system calibration device, a calibration method and an industrial robot. BACKGROUND

[0002] With the rapid development of industrial robot technology, more and more product manufacturing workshops use industrial robots for automatic production, or for automatic stacking operations in the warehouse link. In the process of using the machining tool on the industrial robot mechanical arm to automatically process the workpiece, the workpiece coordinate system is generally used to make the position of the machining action applied to the workpiece by the robot more accurate. When stacking, the position of the bearing platform has accuracy requirements, and the stacking position also needs to be aligned through the workpiece coordinate system.

[0003] However, as the working time of the robot machining production line accumulates, the fixed workpiece on the workbench often produces a certain pose deviation due to external forces such as vibration, at which time there may be a certain error between the workpiece coordinate system and the initial workpiece coordinate system calibrated before processing, thereby affecting the accuracy of the processing position and the stability of the processing quality. Therefore, after the robot machining production line works for a long time, the workpiece coordinate system needs to be recalibrated to reflect the accurate position of the workpiece displacement in real time. The stacking operation scene has the same problem, and the bearing platform may also displace.

[0004] At present, three-point method is commonly used to calibrate the workpiece coordinate system, and the calibration is generally performed by manual operation. The calibration position accuracy is highly dependent on the operation experience and proficiency of the workers, and the accuracy stability is poor, which is time-consuming and laborious, and seriously affects the working efficiency and processing quality of the robot machining automatic production line. SUMMARY

[0005] One of the purposes of the present application is to provide a workpiece coordinate system calibration device for an industrial robot, which sets four mark points on the workpiece to form a two-dimensional coordinate system by a certain method, and obtains the image thereof by a camera; according to the conversion relationship between the camera coordinate system and the base coordinate system, the relative positions of the two coordinate axes and their intersection point of the two-dimensional coordinate system in the base coordinate system are obtained in the camera. Since the position of the base coordinate system of the industrial robot is fixed and unchanged, the position change of the two-dimensional coordinate system newly set on the workpiece in the camera coordinate system can be reflected by the change of the relative position, and the above relative position relationship can be used as the basis for workpiece coordinate system calibration.

[0006] Another objective of this invention is to provide a workpiece coordinate system calibration method for an industrial robot. This method determines a two-dimensional coordinate system and its position within a camera coordinate system by setting four marker points on the workpiece. Based on the transformation relationship between the camera coordinate system and the base coordinate system, the above positions are converted into relative positions within the base coordinate system, and the workpiece coordinate system is calibrated based on these relative positions.

[0007] A third objective of this invention is to provide an industrial robot based on the above-described calibration device and calibration method.

[0008] To achieve the above-mentioned objectives, in a first aspect, the present invention provides a workpiece coordinate system calibration device for an industrial robot, comprising a camera module and a coordinate system marker module; the camera module is detachably fixed to the robotic arm of the industrial robot and communicatively connected to the industrial robot; the coordinate system marker module is fixed to the workpiece being calibrated and is within the field of view of the camera module's imaging lens; the coordinate system marker module includes two marker points x1 and x2 located on a first straight line and two marker points y1 and y2 located on a second straight line; the camera module is used to acquire images of the coordinate system marker module, identify and locate the marker points x1, x2, y1, and y2 from the images, determine their coordinates in the camera coordinate system, and determine the coordinates of the intersection of the first and second straight lines in the camera coordinate system; according to the transformation relationship between the camera coordinate system and the base coordinate system, the camera module is used to determine the slope k of the first straight line relative to the x-axis of the base coordinate system. x The slope k of the second straight line relative to the x-axis of the base coordinate system. y And the coordinates (X0, Y0) of the intersection point in the base coordinate system, through the coordinates (X0, Y0) of the intersection point and the slope k x and slope k y Determine the workpiece coordinate system.

[0009] Furthermore, a first locking structure is fixed on the camera module, and a second locking structure is fixed on the robotic arm of the industrial robot. The camera module is fixed by the cooperation of the first locking structure and the second locking structure.

[0010] Furthermore, the first locking structure is a positioning block, and the second locking structure is a positioning hole. The camera module is fixed by inserting the positioning block into the positioning hole.

[0011] Furthermore, the first locking structure and / or the second locking structure are provided with a camera positioning sensor. The camera positioning sensor is used to send a workpiece coordinate system calibration trigger signal to the camera module and the industrial robot after the first locking structure and the second locking structure are locked in place, so that both of them simultaneously enter the workpiece coordinate system calibration working mode. In the workpiece coordinate system calibration working mode, the robotic arm of the industrial robot stops moving, and the camera module acquires the image of the coordinate system marker module.

[0012] Furthermore, the coordinate system marker module includes two marker strips for attaching to the target object, wherein marker points x1 and x2 are located on the first marker strip, and marker points y1 and y2 are located on the second marker strip.

[0013] Furthermore, the camera module is used to convert the coordinates of the marker points x1, x2, y1, and y2 in the camera coordinate system into coordinates in the base coordinate system (X1, x2, y1, y2). x1 Y x1 ), (X x2 Y x2 ), (X y1 Y y1 ), (X y2 Y y2 Based on the coordinates (X) x1 Y x1 ), (X x2 Y x2 ), (X y1 Y y1 ), (X y2 Y y2 The slope k is calculated using the multi-point averaging method. x and the slope k y .

[0014] Furthermore, at least a portion of the marker points are inherent feature points of the workpiece, including at least one of the hole center, axis center, centroid, and corner vertex.

[0015] Secondly, the present invention provides a workpiece coordinate system calibration method for an industrial robot, comprising: determining the coordinates of two marker points x1 and x2 on the workpiece located on a first straight line in the camera coordinate system; determining the coordinates of two marker points y1 and y2 on the workpiece located on a second straight line in the camera coordinate system; and determining the coordinates of the intersection point of the first straight line and the second straight line in the camera coordinate system; and determining the slope k of the first straight line relative to the x-axis of the base coordinate system according to the transformation relationship between the camera coordinate system and the base coordinate system. x The slope k of the second straight line relative to the x-axis of the base coordinate system. yThe coordinates (X0, Y0) of the intersection point in the base coordinate system; based on the coordinates (X0, Y0) of the intersection point and the slope k x and slope k y Determine the workpiece coordinate system.

[0016] Furthermore, a first marker strip and a second marker strip are respectively affixed to the target component, with marker points x1 and x2 located at different positions on the first marker strip, and marker points y1 and y2 located at different positions on the second marker strip.

[0017] Furthermore, the target component is a tray for stacking workpieces, and the affixing positions of the first and second marker strips are related to the stacking direction of the workpieces on the tray.

[0018] Furthermore, the marker point x1 coincides with the marker point y1 to form the intersection point.

[0019] Furthermore, an image x containing the first marker bar is acquired by the camera, and the marker points x1 and x2 are identified and located by processing the image x; an image y containing the second marker bar is acquired by the camera, and the marker points y1 and y2 are identified and located by processing the image y.

[0020] Furthermore, in response to the positioning signal indicating that the camera is in place, both the camera and the industrial robot are simultaneously triggered to enter the workpiece coordinate system calibration working mode; in the workpiece coordinate system calibration working mode, the robotic arm of the industrial robot is controlled to stop moving, and the camera is controlled to acquire the image x and the image y.

[0021] Furthermore, the coordinates of the marker points x1, x2, y1, y2 in the camera coordinate system are transformed into coordinates in the base coordinate system (X... x1 Y x1 ), (X x2 Y x2 ), (X y1 Y y1 ), (X y2 Y y2 Based on the coordinates (X) x1 Y x1 ), (X x2 Y x2 ), (X y1 Y y1 ), (X y2 Y y2 The slope k is calculated using the multi-point averaging method. x and the slope k y .

[0022] Furthermore, the transformation relationship between the camera coordinate system and the base coordinate system is determined through hand-eye calibration.

[0023] Thirdly, the present invention provides an industrial robot, including a workpiece coordinate system calibration device for an industrial robot as described in any of the technical solutions of the first aspect, or employing a workpiece coordinate system calibration method for an industrial robot as described in any of the technical solutions of the second aspect.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] Four markers are set on the workpiece to form a two-dimensional coordinate system, and the image is captured by a camera. Based on the transformation relationship between the camera coordinate system and the base coordinate system, the relative positions of the two coordinate axes and their intersection points of this two-dimensional coordinate system within the base coordinate system are obtained in the camera. Since the position of the industrial robot's base coordinate system is fixed, the change in the position of the newly set two-dimensional coordinate system on the workpiece within the camera coordinate system can be reflected through this change in relative position. Therefore, the above relative position relationship can serve as the basis for workpiece coordinate system calibration. Because the above process is automatically completed by the camera module's built-in algorithm, the workpiece coordinate system calibration can be automated. Compared to manual calibration, the calibration position is more accurate, the calibration time is greatly reduced, resulting in higher workpiece processing accuracy and efficiency, ultimately leading to better quality stability of the finished product, higher output per unit time, and significantly improved economic benefits.

[0026] Other advantages of the present invention will be further described in some embodiments. Attached Figure Description

[0027] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0028] Figure 1 This is a schematic diagram of the structure of one embodiment of the device of the present invention;

[0029] Figure 2 for Figure 1 The enlarged view of the part circled in A is a magnified schematic diagram of the marker bar;

[0030] Figure 3 for Figure 1 A magnified schematic diagram of the camera module;

[0031] Figure 4 for Figure 3 A view at a different angle (looking down);

[0032] Figure 5 for Figure 4 A magnified view of the part circled in B, i.e., an enlarged schematic diagram of the locking structure;

[0033] Figure 6 This is a flowchart of one embodiment of the method of the present invention.

[0034] In the attached diagram, the industrial robot is 1; the second locking structure is 11; the coordinate system marker module is 2; the camera module is 3; the first locking structure is 31; the camera screen is 32; and the lens is 33. Detailed Implementation

[0035] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0036] It should be noted that the directional terms such as left, right, inside, outside, up, and down mentioned in this article refer to the direction shown in the illustration or the direction conventionally understood by those skilled in the art. They do not represent the direction on the actual object and do not constitute any limitation. They are only used for the convenience of explanation.

[0037] like Figures 1-5 As shown, an embodiment of the workpiece coordinate system calibration device for an industrial robot of the present invention includes a camera module 3 and a coordinate system marker module 2. The camera module 3 is detachably fixed to the robotic arm of the industrial robot 1 and is communicatively connected to the industrial robot 1. The coordinate system marker module 2 is fixed to the workpiece being calibrated and is within the field of view of the imaging lens 33 of the camera module 3. The coordinate system marker module 2 includes two marker points x1 and x2 located on a first straight line and two marker points y1 and y2 located on a second straight line. The camera module 3 is used to acquire images of the coordinate system marker module 2, identify and locate the marker points x1, x2, y1, and y2 from the images, and determine their coordinates in the camera coordinate system, as well as determine the coordinates of the intersection of the first straight line and the second straight line in the camera coordinate system. According to the transformation relationship between the camera coordinate system and the base coordinate system, the camera module 3 is used to determine the slope k of the first straight line relative to the x-axis of the base coordinate system. x The slope k of the second straight line relative to the x-axis of the base coordinate system. y And the coordinates (X0, Y0) of the intersection point in the base coordinate system, through the coordinates (X0, Y0) of the intersection point and the slope k x and slope k y Determine the workpiece coordinate system.

[0038] In this embodiment, the lens 33 of the camera module 3 generally needs to be directly facing the coordinate system marker module 2 to ensure image capture quality. Each pair of the four marker points x1, x2, y1, and y2 defines a coordinate axis; that is, the first straight line connecting x1 and x2 forms the first coordinate axis or x-axis, and the second straight line connecting y1 and y2 forms the second coordinate axis or y-axis, thus forming a new two-dimensional coordinate system within the camera coordinate system environment. The angle between the two coordinate axes of this two-dimensional coordinate system can be a right angle or an oblique angle depending on the actual working conditions of the industrial robot 1. Since there is a definite coordinate transformation relationship between the camera coordinate system and the base coordinate system of the industrial robot 1, the first coordinate axis, the second coordinate axis, and their intersection point (i.e., the origin of the two-dimensional coordinate system) of this two-dimensional coordinate system under the camera coordinate system can all be converted into spatial positions under the base coordinate system. Specifically, for the first coordinate axis, this spatial position is its slope k relative to the x-axis of the base coordinate system. x The second coordinate axis is the slope k relative to the y-axis of the base coordinate system. y The intersection point, which is the origin of the coordinate system, has coordinates (X0, Y0) in the base coordinate system. Given the slope k... x Slope k y By finding the origin (X0, Y0), the workpiece coordinate system in a base coordinate system environment can be determined.

[0039] In this embodiment, the camera module 3 can be functionally divided into at least four organic components: an image acquisition unit, an image processing unit, a position transformation calculation unit, and a communication unit. The image acquisition unit captures images of the coordinate system marker module 2 and displays them in real-time on the camera screen 32, allowing for image quality monitoring; if the image is unclear, it can be retaken. The image processing unit processes the image, identifies four marker points, forms two coordinate axes, and obtains the intersection of the two coordinate axes or their extensions. The position transformation calculation unit calculates the slope k based on the transformation relationship between the camera coordinate system and the base coordinate system. x Slope k y The coordinate origin (X0, Y0) and the communication unit are used for data communication with the industrial robot 1, enabling data sharing and motion synchronization between the two. These functions are all implemented automatically, greatly improving the convenience and reliability of workpiece coordinate system calibration operations, resulting in higher calibration accuracy and shorter calibration time.

[0040] In this embodiment, the camera module 3 is detachably mounted on the robotic arm of the industrial robot 1. The mounting position is unique. The camera module 3 is installed when calibration is required and removed after calibration is completed, achieving plug-and-play functionality. The installation and use are convenient and efficient.

[0041] In this embodiment, as the name suggests, the target object is the object that the industrial robot needs to aim at constantly during operation to ensure the accuracy of the robot's work. The target object varies depending on the application scenario of the industrial robot. For example, in a workpiece processing scenario, the target object is the workpiece being processed. In a workpiece palletizing scenario, the target object is the support platform, such as a pallet, that supports multiple layers of workpieces for stacking.

[0042] like Figures 3-5 As shown, in one embodiment of the workpiece coordinate system calibration device for the industrial robot of the present invention, a first locking structure 31 is fixed on the camera module 3, and a second locking structure 11 is fixed on the robotic arm of the industrial robot 1. The camera module 3 is fixed by the cooperation of the first locking structure 31 and the second locking structure 11. In this embodiment, the camera module 3 and the robotic arm of the industrial robot 1 are quickly locked and fixed or disassembled by the mutual cooperation of the first locking structure 31 and the second locking structure 11, and the locking position of the two is unique, which can ensure the accurate installation position of the camera module 3 and achieve the convenience of installation / disassembly.

[0043] like Figures 3-5 As shown, in one embodiment of the workpiece coordinate system calibration device for the industrial robot of the present invention, the first locking structure 31 is a positioning block, and the second locking structure 11 is a positioning hole. The camera module 3 is fixed by inserting the positioning block into the positioning hole. In this embodiment, the positioning block can be button-shaped, and the positioning hole is a round hole. The two are locked by interference fit, which is simple to install.

[0044] like Figure 1 As shown, in one embodiment of the workpiece coordinate system calibration device for the industrial robot of the present invention, a camera positioning sensor is provided on the first locking structure 31 and / or the second locking structure 11. The camera positioning sensor is used to send a workpiece coordinate system calibration trigger signal to the camera module 3 and the industrial robot 1 after the first locking structure 31 and the second locking structure 11 are locked in place, so that both of them simultaneously enter the workpiece coordinate system calibration working mode. In the workpiece coordinate system calibration working mode, the robotic arm of the industrial robot 1 stops moving, and the camera module 3 acquires the image of the coordinate system marker module 2. In this embodiment, the camera positioning sensor can be any type of sensor that can sense position, such as a photoelectric sensor or a proximity switch. Once locked in place, the photoelectric sensor is blocked or the proximity switch is pressed, generating a trigger signal to start the workpiece coordinate system calibration working mode, which can realize plug-and-play, fool-proof calibration and is very convenient to use.

[0045] like Figure 1 and Figure 2As shown, in one embodiment of the workpiece coordinate system calibration device for an industrial robot of the present invention, the coordinate system marking module 2 includes two marking strips for attaching to the workpiece. The marking points x1 and x2 are located on the first marking strip, and the marking points y1 and y2 are located on the second marking strip. In this embodiment, two marking strips are attached to the surface of the workpiece, and the positions of the marking strips are fixed relative to the workpiece. If the position of the workpiece changes, the position of the marking strips changes synchronously. This allows the position change of the workpiece to be reflected by the position change of the marking strips. A two-dimensional coordinate system is then established based on the marking strips, which can cleverly simplify the handling of complex position change problems and make the calibration operation quick and efficient. In this embodiment, at least some of the marking points can be inherent feature points of the workpiece, including at least one of the following: hole center, axis center, centroid, and corner vertex. The positions of these feature points are fixed and can play the same role as the marking points on the marking strips. This can partially or completely eliminate the need for marking strips, eliminating the step of attaching marking strips and saving time and costs.

[0046] In one embodiment of the workpiece coordinate system calibration device for the industrial robot of the present invention, the camera module 3 is used to convert the coordinates of the marker points x1, x2, y1, y2 in the camera coordinate system into coordinates (X, Y, Y) in the base coordinate system, respectively. x1 Y x1 ), (X x2 Y x2 ), (X y1 Y y1 ), (X y2 Y y2 Based on the coordinates (X) x1 Y x1 ), (X x2 Y x2 ), (X y1 Y y1 ), (X y2 Y y2 The slope k is calculated using the multi-point averaging method. x and the slope k y In this embodiment, for example, the two slopes can be calculated using the two-point averaging method. That is, the slope is calculated for each of the two marker points on each coordinate axis, and then the average is calculated. The specific calculation formula is as follows:

[0047] k x =[(Y x1 -Y0 / X x1 -X0)+(Y x2 -Y0 / X x2 -X0)] / 2;

[0048] k y =[(Yx1 -Y0 / X x1 -X0)+(Y x2 -Y0 / X x2 -X0)] / 2.

[0049] Of course, you can also choose a third point or more points for calculation. Since camera recognition has a certain degree of error, using the multi-point averaging method can more accurately calculate the slope value.

[0050] like Figure 6 As shown, one embodiment of the workpiece coordinate system calibration method for an industrial robot of the present invention includes: determining the coordinates of two marker points x1 and x2 on the workpiece located on a first straight line in the camera coordinate system; determining the coordinates of two marker points y1 and y2 on the workpiece located on a second straight line in the camera coordinate system; and determining the coordinates of the intersection point of the first straight line and the second straight line in the camera coordinate system; and determining the slope k of the first straight line relative to the x-axis of the base coordinate system according to the transformation relationship between the camera coordinate system and the base coordinate system. x The slope k of the second straight line relative to the x-axis of the base coordinate system. y The coordinates (X0, Y0) of the intersection point in the base coordinate system; based on the coordinates (X0, Y0) of the intersection point and the slope k x and slope k y Determine the workpiece coordinate system.

[0051] In this embodiment, each of the four marker points x1, x2, y1, and y2 is paired to define a coordinate axis. Specifically, the first straight line connecting x1 and x2 forms the first coordinate axis (x-axis), and the second straight line connecting y1 and y2 forms the second coordinate axis (y-axis), creating a new two-dimensional coordinate system within the camera coordinate system environment. The angle between the two coordinate axes of this two-dimensional coordinate system can be a right angle or an oblique angle, depending on the actual working conditions of the industrial robot 1. Taking palletizing as an example, the workpiece is a pallet that carries the workpiece. Palletizing involves placing workpieces one by one on the pallet along the x-axis and y-axis, stacking the next layer after the previous one. If the workpieces arranged along the x-axis are required to be perpendicular to each other with those arranged along the y-axis, then the angle between the two coordinate axes must be a right angle. If perpendicularity is not required, then the angle between the two coordinate axes is an oblique angle, entirely determined by the actual working conditions.

[0052] In this embodiment, since there is a definite coordinate transformation relationship between the camera coordinate system and the base coordinate system of the industrial robot 1, the first coordinate axis, the second coordinate axis, and the intersection of the two-dimensional coordinate system under the camera coordinate system, i.e., the origin of the two-dimensional coordinate system, can all be converted into spatial positions under the base coordinate system. Specifically, for the first coordinate axis, this spatial position is its slope k relative to the x-axis of the base coordinate system. xThe second coordinate axis is the slope k relative to the y-axis of the base coordinate system. y The intersection point, which is the origin of the coordinate system, has coordinates (X0, Y0) in the base coordinate system. Given the slope k... x Slope k y By establishing the coordinate origin (X0, Y0), the workpiece coordinate system within a base coordinate system environment can be determined. Since these functions are all performed automatically, the convenience and reliability of workpiece coordinate system calibration operations are greatly improved, resulting in higher calibration accuracy and shorter calibration time.

[0053] In one embodiment of the workpiece coordinate system calibration method for an industrial robot of the present invention, a first marker strip and a second marker strip are respectively affixed to the workpiece being calibrated. The marker points x1 and x2 are located at different positions on the first marker strip, and the marker points y1 and y2 are located at different positions on the second marker strip. In this embodiment, two marker strips are affixed to the surface of the workpiece, and the positions of the marker strips are fixed relative to the workpiece. If the position of the workpiece changes, the position of the marker strips changes synchronously. This allows the position change of the workpiece to be reflected by the position change of the marker strips. A two-dimensional coordinate system is then established based on the marker strips, which cleverly simplifies the handling of complex position change problems, making the calibration operation quick and efficient. In this embodiment, at least some of the marker points can be inherent feature points of the workpiece, including at least one of the following: hole center, axis center, centroid, and corner vertex. The positions of these feature points are fixed, and they can play the same role as the marker points on the marker strips. This can partially or completely eliminate the need for marker strips, eliminating the step of affixing marker strips and saving time and costs.

[0054] In one embodiment of the workpiece coordinate system calibration method for an industrial robot of the present invention, the workpiece to be calibrated is a pallet for stacking workpieces, and the pasting positions of the first and second marker strips are related to the stacking direction of the workpieces on the pallet. In this embodiment, the application scenario is palletizing, that is, stacking several workpieces on the pallet in multiple layers, each layer having M rows and N columns, and pasting two marker strips on the pallet. If it is required that the row direction and column direction of each layer of workpieces are perpendicular to each other, then the first and second marker strips must also be perpendicular to each other when pasted; if it is required that the angle between the row direction and column direction of each layer of workpieces is an acute angle α, then the angle between the pasted first and second marker strips is also α. In this way, the pasting position of the marker strips can be flexibly adjusted according to the actual use situation, which is highly adaptable and has a wide range of application scenarios.

[0055] In one embodiment of the workpiece coordinate system calibration method for industrial robots of the present invention, the marker point x1 and the marker point y1 coincide to form the intersection point. In this embodiment, the two marker bars intersect directly, and the intersection point is shared by two coordinate axes. That is, only three marker points are actually needed to create a two-dimensional coordinate system, making subsequent processing simpler and more efficient.

[0056] In one embodiment of the workpiece coordinate system calibration method for an industrial robot of the present invention, an image x of the first marker strip is acquired by a camera, and the marker points x1 and x2 are identified and located by processing the image x; an image y of the second marker strip is acquired by a camera, and the marker points y1 and y2 are identified and located by processing the image y. In this embodiment, the camera includes an image acquisition unit and an image processing unit, wherein the image acquisition unit captures an image of the coordinate system marker module 2, and the image processing unit processes the image to find four marker points and form two coordinate axes, obtaining the intersection of the two coordinate axes or their extensions. In this way, the position of the newly established two-dimensional coordinate system in the camera coordinate system can be quickly and accurately obtained through image processing algorithms, providing accurate data for subsequent processing.

[0057] In one embodiment of the workpiece coordinate system calibration method for an industrial robot according to the present invention, in response to a positioning signal indicating that the camera is in position, both the camera and the industrial robot simultaneously enter the workpiece coordinate system calibration working mode. In this working mode, the robotic arm of the industrial robot is controlled to stop its movement, and the camera is controlled to acquire the image x and image y. In this embodiment, the camera positioning sensor can be any type of sensor capable of sensing position, such as a photoelectric sensor or a proximity switch. Once locked in position, the photoelectric sensor is blocked or the proximity switch is pressed, generating a trigger signal to activate the workpiece coordinate system calibration working mode. This allows for plug-and-play, user-friendly calibration, making it extremely convenient to use.

[0058] In one embodiment of the workpiece coordinate system calibration method for the industrial robot of the present invention, the coordinates of the marker points x1, x2, y1, y2 in the camera coordinate system are converted into coordinates in the base coordinate system (X... x1 Y x1 ), (X x2 Y x2 ), (X y1 Y y1 ), (X y2 Y y2 Based on the coordinates (X) x1 Y x1 ), (X x2 Y x2 ), (X y1 Y y1 ), (X y2 Y y2 The slope k is calculated using the multi-point averaging method. x and the slope k y In this embodiment, for example, the two slopes can be calculated using the two-point averaging method. That is, the slope is calculated for each of the two marker points on each coordinate axis, and then the average is calculated. The specific calculation formula is as follows:

[0059] k x =[(Y x1 -Y0 / X x1 -X0)+(Y x2 -Y0 / X x2 -X0)] / 2;

[0060] k y =[(Y x1 -Y0 / X x1 -X0)+(Y x2 -Y0 / X x2 -X0)] / 2.

[0061] Of course, you can also choose a third point or more points for calculation. Since camera recognition has a certain degree of error, using the multi-point averaging method can more accurately calculate the slope value.

[0062] Based on the slope k obtained in this embodiment x and slope k y The angle αx between the first coordinate axis and the X-axis of the base coordinate system and the angle αy between the second coordinate axis and the X-axis of the base coordinate system can be calculated using the formula k = tanα.

[0063] In one embodiment of the workpiece coordinate system calibration method for an industrial robot of the present invention, the transformation relationship between the camera coordinate system and the base coordinate system is determined through hand-eye calibration. In this embodiment,

[0064] One embodiment of the industrial robot of the present invention includes a workpiece coordinate system calibration device for an industrial robot as described in any of the above-described embodiments of the workpiece coordinate system calibration device for an industrial robot, or a workpiece coordinate system calibration method for an industrial robot as described in any of the above-described embodiments of the workpiece coordinate system calibration method for an industrial robot. In this embodiment, the application scenario of the industrial robot can be the direct processing of workpieces, in which case the marker points are set on the workpiece. The application scenario of the industrial robot can also be palletizing, in which case the marker points are set on the workpiece support platform, such as a pallet. Any embodiment of the industrial robot of the present invention necessarily possesses the advantages of any of the above-described embodiments of the workpiece coordinate system calibration device for an industrial robot and / or embodiments of the workpiece coordinate system calibration method for an industrial robot, which will not be elaborated further here.

[0065] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention. The above preferred features can be used in any combination without conflict.

Claims

1. A workpiece coordinate system calibration device for an industrial robot, characterized in that, It includes a camera module and a coordinate system marker module; the camera module is detachably fixed to the robotic arm of an industrial robot and communicates with the industrial robot; the coordinate system marker module is fixed to the target object and is located in the field of view of the camera module's imaging lens; The coordinate system marker module includes two marker points x1 and x2 located on the first straight line and two marker points y1 and y2 located on the second straight line; The camera module is used to acquire images from the coordinate system marker module, identify and locate marker points x1, x2, y1, and y2 from the images, and determine their coordinates in the camera coordinate system, as well as the coordinates of the intersection of the first and second lines in the camera coordinate system. Based on the transformation relationship between the camera coordinate system and the base coordinate system, the camera module is used to determine the slope k of the first line relative to the x-axis of the base coordinate system. x The slope k of the second straight line relative to the x-axis of the base coordinate system. y And the coordinates (X0, Y0) of the intersection point in the base coordinate system, through the coordinates (X0, Y0) of the intersection point and the slope k x and slope k y Determine the workpiece coordinate system.

2. The workpiece coordinate system calibration device for an industrial robot according to claim 1, characterized in that, The camera module is fixed with a first locking structure, and the robotic arm of the industrial robot is fixed with a second locking structure. The camera module is fixed by the cooperation of the first locking structure and the second locking structure.

3. The workpiece coordinate system calibration device for an industrial robot according to claim 2, characterized in that, The first locking structure and / or the second locking structure are equipped with a camera positioning sensor. The camera positioning sensor is used to send a workpiece coordinate system calibration trigger signal to the camera module and the industrial robot after the first locking structure and the second locking structure are locked in place, so that both of them simultaneously enter the workpiece coordinate system calibration working mode. In the workpiece coordinate system calibration working mode, the robotic arm of the industrial robot stops moving, and the camera module acquires the image of the coordinate system marker module.

4. The workpiece coordinate system calibration device for an industrial robot according to claim 1, characterized in that, The coordinate system marker module includes two marker strips for attaching to the target object. Marker points x1 and x2 are located on the first marker strip, and marker points y1 and y2 are located on the second marker strip.

5. A method for calibrating the workpiece coordinate system of an industrial robot, characterized in that, include: Determine the coordinates of two marker points x1 and x2 on the workpiece located on the first straight line in the camera coordinate system, determine the coordinates of two marker points y1 and y2 on the workpiece located on the second straight line in the camera coordinate system, and determine the coordinates of the intersection of the first straight line and the second straight line in the camera coordinate system. Based on the transformation relationship between the camera coordinate system and the base coordinate system, the slope k of the first straight line relative to the x-axis of the base coordinate system is determined. x The slope k of the second straight line relative to the x-axis of the base coordinate system. y , and the coordinates (X0, Y0) of the intersection point in the base coordinate system. Based on the intersection point coordinates (X0, Y0) and the slope k x and slope k y Determine the workpiece coordinate system.

6. The workpiece coordinate system calibration method for an industrial robot according to claim 5, characterized in that, The target is affixed with a first marker strip and a second marker strip, respectively. The marker points x1 and x2 are located at different positions on the first marker strip, and the marker points y1 and y2 are located at different positions on the second marker strip.

7. The workpiece coordinate system calibration method for an industrial robot according to claim 6, characterized in that, The target component is a tray for stacking workpieces, and the affixing positions of the first and second marker strips are related to the stacking direction of the workpieces on the tray.

8. The workpiece coordinate system calibration method for an industrial robot according to claim 6, characterized in that, The intersection point is formed by the coincidence of the marker point x1 and the marker point y1.

9. The workpiece coordinate system calibration method for an industrial robot according to claim 6, characterized in that, The camera acquires an image x containing the first marker bar, and the marker points x1 and x2 are identified and located by processing the image x; the camera acquires an image y containing the second marker bar, and the marker points y1 and y2 are identified and located by processing the image y.

10. The workpiece coordinate system calibration method for an industrial robot according to claim 9, characterized in that, In response to a positioning signal indicating that the camera is in place, both the camera and the industrial robot are triggered to enter the workpiece coordinate system calibration mode. In the workpiece coordinate system calibration mode, the robotic arm of the industrial robot is controlled to stop moving, and the camera is controlled to acquire the image x and the image y.

11. The workpiece coordinate system calibration method for an industrial robot according to claim 5, characterized in that, The coordinates of the marker points x1, x2, y1, and y2 in the camera coordinate system are transformed into coordinates in the base coordinate system (X). x1 Y x1 ), (X) x2 Y x2 ), (X) y1 Y y1 ), (X) y2 Y y2 Based on the coordinates (X) x1 Y x1 ), (X) x2 Y x2 ), (X) y1 Y y1 ), (X) y2 Y y2 The slope k was calculated using the multi-point averaging method. x and the slope k y .

12. The workpiece coordinate system calibration method for an industrial robot according to claim 5, characterized in that, The transformation relationship between the camera coordinate system and the base coordinate system is determined by hand-eye calibration.

13. An industrial robot, characterized in that, Includes the workpiece coordinate system calibration device for an industrial robot as described in any one of claims 1-4, or employs the workpiece coordinate system calibration method for an industrial robot as described in any one of claims 5-12.

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