Welding tracking method and welding tracking device

Abstract

The present application provides a welding tracking method comprising: processing a weld spot area image acquired by an image acquisition device to obtain weld spot position information and posture information; performing interpolation processing based on the weld spot position information and posture information and the real-time position of an industrial robot to obtain a set of weld spot interpolation data; when the distance between the real-time position of the industrial robot and the first weld spot interpolation data in the set of weld spot interpolation data is less than a predetermined distance, obtaining an interpolation value based on the real-time position and the first weld spot interpolation data, and sending the interpolation value to the industrial robot for interpolation control. By acquiring the position and posture of the weld spot in real time and calculating the position interpolation data and posture interpolation based on the real-time position of the industrial robot, the accuracy of tracking control is improved; sending interpolation instructions in real time according to the communication cycle of the industrial robot achieves interpolation continuity, thereby realizing continuous welding tracking.

Description

Technical Field

[0001] The present application relates to the technical field of automatic welding, and in particular to a welding tracking method and a welding tracking device. Background Art

[0002] With the advancement of technology, manual welding can no longer meet the high-quality and high-output demands of industrial production. In recent years, industrial robotic welding technology has rapidly developed and become widely used, not only reducing the need for personnel during the welding process but also improving welding quality. However, during robotic welding, thermal deformation of the weldment and insufficient positioning accuracy of the industrial robot can cause the actual welding trajectory to deviate from the intended one. To ensure welding quality, it is necessary to track the welding torch position in real time and use position interpolation to correct the welding torch's motion trajectory, ensuring that the actual welding trajectory coincides with the intended one.

[0003] Existing weld seam tracking equipment utilizes the principle of triangulated laser measurement. However, this method only captures the spatial position of the weld point and cannot capture the posture data of the industrial robot when the welding torch head is at the weld point, making accurate tracking impossible. Furthermore, during the welding tracking process, the identified weld point location is located ahead of the welding torch head's welding path, making real-time continuous tracking impossible due to timing issues. Furthermore, due to the harsh environment, complex lighting, and high vibrations experienced during industrial robot welding, the interpolated position data obtained by the host computer deviates, affecting weld position accuracy. Summary of the Invention

[0004] In order to solve the problems of low tracking accuracy and inability to track continuously in the current weld tracking process, the present application provides a welding tracking method and welding tracking equipment for industrial robot welding.

[0005] According to a first aspect of the present application, a welding tracking method is provided, comprising:

[0006] Processing the weld area image acquired by the image acquisition device to obtain weld position information and posture information;

[0007] Performing interpolation processing based on the welding point position information and posture information and the real-time position of the industrial robot to obtain a set of welding point interpolation data;

[0008] When the distance between the real-time position of the industrial robot and the first weld point interpolation data in the set of weld point interpolation data is less than a predetermined distance, an interpolation value is obtained according to the real-time position and the first weld point interpolation data and the interpolation value is sent to the industrial robot for interpolation control.

[0009] According to some embodiments of the present application, the image acquisition device includes a line laser emitter and an area array industrial camera, and the weld area image includes an image of the fan-shaped line laser plane emitted by the line laser emitter after being imaged by the area array industrial camera.

[0010] According to some embodiments of the present application, the welding tracking method further includes: sorting the set of welding point interpolation data.

[0011] According to some embodiments of the present application, the welding tracking method further includes: performing fitting processing on the set of welding point interpolation data.

[0012] According to some embodiments of the present application, the welding tracking method further includes: setting the predetermined distance according to a communication cycle of the industrial robot.

[0013] According to some embodiments of the present application, the distance includes: a projection distance along the welding direction between the real-time position of the industrial robot and the first weld point interpolation data in the set of weld point interpolation data.

[0014] According to some embodiments of the present application, the weld interpolation data includes: weld point position coordinates and angle coordinates; the interpolation value includes position interpolation data and posture interpolation data; the position interpolation data is the difference between the real-time position of the industrial robot and the weld point position coordinates in the first weld point interpolation data; the posture interpolation data is the angle coordinates in the first weld point interpolation data.

[0015] According to some embodiments of the present application, the communication cycle of the industrial robot is 12 ms, and the predetermined distance is 3 mm.

[0016] According to another aspect of the present application, a welding tracking device is provided for executing the above-mentioned welding tracking method, comprising:

[0017] industrial robots;

[0018] A welding device, provided at the end of the industrial robot;

[0019] An image acquisition device, provided in the module of the industrial robot, for acquiring the position and posture information of the welding points at the end of the welding device;

[0020] A control device is connected to the industrial robot and the welding device, and is used to interpolate the real-time position of the industrial robot according to the welding point position and posture information.

[0021] According to some embodiments of the present application, the image acquisition device includes:

[0022] a line laser sensor for emitting a fan-shaped laser plane toward an end of the welding device; and

[0023] An area array industrial camera is used to image the fan-shaped laser plane.

[0024] The welding tracking method and welding tracking device provided in this application can obtain the position and posture of the welding point in real time through a line laser sensor and an area array industrial camera, and calculate the position interpolation data and posture interpolation according to the real-time position of the industrial robot, thereby improving the accuracy of tracking control; the continuously obtained welding point positions are sorted and fitted to ensure the unidirectional stability and smoothness of the tracking trajectory; interpolation instructions are sent in real time according to the communication cycle of the industrial robot to achieve the continuity of interpolation, thereby ensuring that the welding tracking can operate continuously, smoothly and stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without exceeding the scope of protection required by this application.

[0026] Figure 1 A schematic diagram of a welding tracking device according to an exemplary embodiment of the present application is shown;

[0027] Figure 2 A partial schematic diagram of a welding tracking device according to an exemplary embodiment of the present application is shown;

[0028] Figure 3 A flow chart of a welding tracking method according to an exemplary embodiment of the present application is shown;

[0029] Figure 4 A schematic diagram of an image captured by an image capture device according to an exemplary embodiment of the present application is shown;

[0030] Figure 5 A schematic diagram showing a process of a welding tracking method executed by a welding tracking device according to an exemplary embodiment of the present application is shown. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0032] As used herein, the terms "comprise," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0033] References to "embodiments" herein mean that predetermined features, structures, or characteristics described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0034] In order to solve the problems of insufficient accuracy and inability to continuously track welding tracking during the welding process of industrial robots, the present application provides a welding tracking device and a welding tracking method.

[0035] The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0036] Figure 1 A schematic diagram of a welding tracking device according to an exemplary embodiment of the present application is shown; Figure 2 A partial schematic diagram of a welding tracking device according to an exemplary embodiment of the present application is shown.

[0037] like Figure 1 and Figure 2 As shown, according to an exemplary embodiment of the present application, a welding tracking device 1000 is provided for executing the welding tracking method provided in the present application. The welding tracking device 1000 includes: an industrial robot 100, a welding device 200, an image acquisition device 300 and a control device 400.

[0038] The welding device 200 is mounted on the end of the industrial robot 100, and the image acquisition device 300 is attached to the end of the industrial robot 100 via a connecting component 500. For example, the welding device 200 can be a welding gun, fixedly mounted on the end of the industrial robot via a suitable flange; the connecting component 500 can be a flange bracket, which can be secured to the welding gun flange on the end of the industrial robot 100 via a snap 510. The image acquisition device 300 is secured to the flange bracket. The industrial robot 100 and the image acquisition device 300 are connected to the control device 400 via a cable (e.g., an RJ45 cable).

[0039] According to some embodiments of the present application, the industrial robot 100 may be a serial robot with six degrees of freedom, such as a six-degree-of-freedom robotic arm. During the welding process, the industrial robot 100 carries a welding torch and performs welding along a predetermined trajectory. In the welding tracking device 1000 provided in the present application, an image acquisition device 300 is positioned in front of the welding direction (i.e., the welding direction) along the direction of movement of the welding torch and is used to capture images of the weld points in real time. The control device 400 may be a host computer that, on the one hand, communicates with the industrial robot 100, transmits control signals, and controls the movement of the industrial robot 100. On the other hand, it receives the weld point images captured by the image acquisition device 300 and, after processing, obtains position interpolation data and posture interpolation data of the industrial robot, thereby further controlling the motion trajectory of the industrial robot and correcting the welding trajectory.

[0040] According to some embodiments of the present application, the image acquisition device 300 may include a linear laser emitter 310 and an industrial area array camera 320. Figure 1 As shown, the linear laser emitter 310 and the industrial area array camera 320 can be secured to the flange bracket 500 via a fixing clip 510. The fixing clip 510 can be a triangular connector. The linear laser emitter 310 can be positioned at the end of the triangular connector facing the welding direction (i.e., the distal end) and has a locking function. By adjusting the mounting angle of the linear laser emitter 310, a linear laser can be emitted toward the welding gun head area. The industrial area array camera 320 is positioned at the end of the triangular connector facing the welding gun (i.e., the proximal end) to receive the linear laser emitted or scattered from the welding gun head area and obtain an image of the weld area. For example, the linear laser emitter emits a fan-shaped laser plane toward the weld location of the welded part. The weld location area and the fan-shaped laser plane are within the field of view of the industrial area array camera.

[0041] According to some embodiments of the present application, the forward direction of the welding gun during welding operations (i.e., the welding direction) can be defined as forward, i.e., the welding gun x-direction; the normal to the end flange of the industrial robot 100 is the depth direction, i.e., the welding gun z-direction; and the welding gun y-direction is determined by the right-hand rule. The industrial area scan camera 320 is positioned in front of the welding gun, while the linear laser emitter 310 is positioned in front of the industrial area scan camera 320. A flange bracket ensures that the optical axis of the industrial area scan camera is parallel to the welding gun z-direction, and the angle between the optical plane of the linear laser emitter and the welding gun z-axis can be set to approximately 30 degrees. The linear laser emitter 310 and the industrial area scan camera 320 can capture real-time images of the weld point and its surroundings, and calculate the weld point position and posture data after image processing. The industrial area scan camera 320 is connected to the control device 400 via an RJ45 interface cable, transmitting the captured images to the control device 400.

[0042] Before image acquisition, the image acquisition device needs to be calibrated, for example, by performing camera calibration, hand-eye calibration, and line-plane calibration. Camera calibration can eliminate camera lens distortion and prevent errors caused by camera lens distortion. Hand-eye calibration can determine the relative position between the area array industrial camera and the welding gun head, so that the position coordinates in the camera coordinate system identified by the camera can be converted to the welding gun coordinate system. Line-plane calibration can determine the relative position of the line-plane and the area array industrial camera, thereby calculating the position of the weld in the camera coordinate system based on the position of the weld in the area array industrial camera image.

[0043] According to some embodiments of the present application, the control device 400 (eg, a host computer) can process the image (eg, Figure 4 ) to perform image processing and calculate the weld point position data and posture data in the image. According to some embodiments of the present application, the control device 400 may also calculate the position interpolation value data and posture interpolation value data of the industrial robot 100 based on the real-time position of the industrial robot 100 and the calculated weld point position data and posture data. According to some embodiments of the present application, the control device 400 may also cache and sort the interpolation value data at different times to generate continuous and smooth interpolation value data, and in conjunction with the communication cycle of the industrial robot, timely transmit the interpolation data to the industrial robot for interpolation control, thereby achieving continuous and smooth welding tracking.

[0044] Figure 3 A flow chart of a welding tracking method according to an exemplary embodiment of the present application is shown.

[0045] According to another aspect of the present application, a welding tracking method is also provided, which is applied to Figure 1 and Figure 2 The welding tracking equipment shown. Figure 3 As shown, the welding tracking method provided by the present application includes the following steps.

[0046] In step S310, the welding spot area image acquired by the image acquisition device is processed to obtain welding spot position information and posture information.

[0047] According to some embodiments of the present application, an image acquisition device may include a linear laser emitter and an industrial area array camera. The industrial area array camera is positioned in front of the welding torch, along the direction of movement of the welding torch. The optical axis of the industrial area array camera is parallel to the normal (z-axis) of the welding torch flange, and the optical plane of the linear laser emitter forms a predetermined angle (e.g., 30 degrees) with the optical axis of the industrial area array camera.

[0048] According to some embodiments of the present application, a fan-shaped line laser plane can be emitted to the welding spot area by a linear laser emitter, and an image of the welding spot area can be obtained after imaging by an industrial camera. Figure 4 After image filtering, threshold segmentation, line matching, and line fitting, the weld area image obtained by the industrial camera can include two intersecting lines formed on the welded part. The intersection point J of the two intersecting lines is the weld. The information (position information and angle information) of the two intersecting lines and the intersection point in the image is the weld position information and posture information. Subsequent calculations and coordinate conversions can be performed to obtain the weld position coordinates and posture coordinates. According to some embodiments of the present application, a circle can be drawn with the intersection point J as the center and a certain pixel length as the radius to obtain the four intersection points (E, E', F, F') of the two lines and the circle, and form two straight line segments. The center of the circle and the four intersection points provide the weld position information and posture information.

[0049] According to some embodiments of the present application, the position information and posture information in the image coordinates can be transformed into the weld point position and posture data in the welding gun coordinate system through a series of coordinate transformations. For example, the transformation process can be: first transforming from the image coordinate system to the camera coordinate system, and then transforming from the camera coordinate system to the welding gun coordinate system.

[0050] In step S320, interpolation processing is performed based on the welding point position information and posture information and the real-time position of the industrial robot to obtain a set of welding point interpolation data.

[0051] After converting the weld point position and posture information acquired from the image to the welding gun coordinate system, the weld point position and posture data in the welding gun coordinate system can be calculated based on the intersection of two lines and the four intersections of the two lines and the circle. These data are stored in a Cartesian coordinate system as a set of coordinate data (e.g., X, Y, Z, A, B, C), hereinafter referred to as coordinate points. The weld point position data includes the weld point position coordinates in the welding gun coordinate system, while the posture data includes the angular coordinates of the industrial robot at the weld point location.

[0052] After obtaining the weld point position data and posture data, the real-time position data of the industrial robot can be obtained from the control device. Interpolation processing is then performed based on the weld point position data and posture data, as well as the real-time position data of the industrial robot, to obtain a set of weld point interpolation data. According to some embodiments of the present application, the weld point interpolation data includes position interpolation data and posture interpolation data. According to some embodiments of the present application, the weld point position information and posture information can include position information and posture information of a set of weld points (a set of weld point coordinate points) obtained through multiple acquisitions and image processing.

[0053] According to some embodiments of the present application, during the interpolation calculation process, a group of weld point coordinate points can be sorted and fitted before the interpolation calculation is performed. For example, a group of weld point coordinate points can be sorted. For example, the weld point coordinate points can be sorted according to the order in which they are projected on a predetermined trajectory. When a new weld point coordinate point is obtained, the coordinate point queue is traversed and the new weld point coordinate point is inserted at the corresponding position. After the sorting process, the unidirectional stability of the interpolated weld point coordinates can be ensured, and the interpolation accuracy can be guaranteed. After sorting, the group of weld point coordinate points can also be fitted. For example, discrete coordinate points can be curve fitted, and the coordinates of abnormal points can be removed to smooth the weld point data, thereby ensuring the smoothness of the motion trajectory of the industrial robot after the interpolation calculation. After sorting and fitting, interpolation processing can be performed based on the industrial robot communication cycle and the obtained real-time position of the industrial robot, thereby generating continuous interpolation coordinate point data.

[0054] According to some embodiments of the present application, during the interpolation calculation process, interpolation processing can be first performed based on a set of welding point coordinate points, the communication cycle of the industrial robot, and the acquired real-time position of the industrial robot. After obtaining a set of interpolation coordinate point data (including welding point position and posture), sorting and fitting processing can be performed to ensure the unidirectional stability of the interpolation coordinate points and the smoothness of the motion trajectory.

[0055] In step S330, when the distance between the real-time position of the industrial robot and the first weld point interpolation data in a set of weld point interpolation data is less than a predetermined distance, an interpolation value is obtained based on the real-time position and the first weld point interpolation data and the interpolation value is sent to the industrial robot for interpolation control.

[0056] Since industrial robots have a communication cycle, in order to achieve continuous interpolation, it is necessary to overcome the timing problem. In the present application, the distance between the real-time position of the industrial robot and the position of the weld is used as the time condition for performing interpolation, so that interpolation control is performed at the appropriate time to achieve continuous interpolation. According to some embodiments of the present application, the coordinate point that ranks first among the sorted interpolation coordinate points is the weld closest to the current welding gun position. The projection distance between the real-time position of the industrial robot and the first weld interpolation data in the welding direction can be calculated, and when the projection distance is less than the preset distance, interpolation is performed. The preset distance can be set according to the communication cycle of the industrial robot. In an embodiment of the present application, the communication cycle of the industrial robot is 12ms, and the preset distance can be 3mm. After executing interpolation, a set of weld interpolation data is updated, for example, the first weld interpolation data is deleted, so as to perform the next interpolation control.

[0057] According to some embodiments of the present application, the interpolated value includes position interpolation data and attitude interpolation data. The position interpolation data is the interpolation value of the real-time position of the industrial robot and the position coordinates in the first interpolation point coordinates; the attitude interpolation data is the angular coordinates in the first interpolation point coordinates.

[0058] Figure 5 A schematic diagram showing a process of a welding tracking method executed by a welding tracking device according to an exemplary embodiment of the present application is shown.

[0059] During the welding tracking method performed by the welding tracking device provided herein, after the industrial robot, area array industrial camera, and line laser transmitter are powered on and connected to a host computer, the welding tracking method can be divided into three processes: image acquisition and processing, interpolation, and industrial robot communication. These three processes operate independently while maintaining necessary information exchange.

[0060] like Figure 5 As shown in Figure 2, the image acquisition and processing process includes the following main steps:

[0061] In S510, a fan-shaped line laser plane is emitted by a line laser transmitter, and an area array industrial camera continuously captures images of the welding spot area and transmits them to a host computer;

[0062] In S520, the host computer performs filtering, segmentation, matching, fitting and other processing on each weld area image, and records the weld position information and angle information in each image, such as the intersection of two intersecting straight lines and the four intersections of two intersecting straight lines and a circle.

[0063] In S530 , the host computer calculates the welding point position data and posture data, such as a set of coordinate data: X, Y, Z, A, B, C, based on the intersection information in the image.

[0064] While the image acquisition and processing process is running, the host computer executes the communication process with the industrial robot. For example, in S610, the host computer communicates with the industrial robot to obtain the real-time position of the welding gun.

[0065] The interpolation process mainly includes the following steps:

[0066] At S710 , the host computer stores a column of weld point position data and posture data (i.e., a set of weld point coordinates) obtained by the image acquisition and processing process;

[0067] In S720, the host computer calculates interpolation data based on the real-time position of the welding gun and a set of stored welding point coordinates;

[0068] In S730, the host computer sorts the interpolated weld point coordinates to ensure the unidirectional stability of the interpolated data;

[0069] At S740, the host computer performs fitting processing on the interpolated weld point coordinates to remove the coordinates of abnormal points to ensure the smoothness of the interpolated data;

[0070] At S740 , the host computer calculates the distance between the first weld point coordinate in a set of weld point coordinate points and the real-time position coordinate of the industrial robot, such as the projected distance along the welding direction;

[0071] At S750, the host computer determines whether the calculated distance meets the preset conditions, for example, the projection distance is less than 3 mm; if the preset conditions are not met, the process returns to S740 to recalculate the projection distance based on the latest real-time position of the industrial robot;

[0072] In S760, when the projection distance meets the preset conditions, the host computer sends an interpolation instruction and corresponding interpolation data to the industrial robot, and deletes the coordinates of the first welding point; the interpolation data includes position interpolation data and posture interpolation data.

[0073] The welding tracking equipment and welding tracking method provided in this application can obtain the position and posture of the welding point in real time through a line laser sensor and an area array industrial camera, and calculate the position interpolation data and posture interpolation according to the real-time position of the industrial robot, thereby improving the accuracy of tracking control; the continuously obtained welding point positions are sorted and fitted to ensure the unidirectional stability and smoothness of the tracking trajectory; interpolation instructions are sent in real time according to the communication cycle of the industrial robot to achieve the continuity of interpolation, thereby ensuring that the welding tracking can operate continuously, smoothly and stably.

[0074] The embodiments of the present application are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only intended to help understand the method and core ideas of the present application. At the same time, changes or modifications made by those skilled in the art based on the ideas of the present application, the specific implementation methods, and the scope of application of the present application, all fall within the scope of protection of the present application. In summary, the contents of this specification should not be construed as limiting the present application.

Claims

1. A welding tracking method, characterized in that: include: Processing the weld area image acquired by the image acquisition device to obtain weld position information and posture information; Performing interpolation processing based on the welding point position information and posture information and the real-time position of the industrial robot to obtain a set of welding point interpolation data; When a projection distance along the welding direction between the real-time position of the industrial robot and the first weld point interpolation data in the set of weld point interpolation data is less than a predetermined distance, an interpolation value is obtained according to the real-time position and the first weld point interpolation data, and the interpolation value is sent to the industrial robot for interpolation control; Wherein, the predetermined distance is set according to the communication cycle of the industrial robot; Wherein, the image acquisition device includes a line laser emitter and an area array industrial camera, and the weld area image includes an image of a fan-shaped line laser plane emitted by the line laser emitter after being imaged by the area array industrial camera; Wherein, the welding point interpolation data includes welding point position coordinates and angle coordinates; The interpolation value includes position interpolation data and posture interpolation data; The position interpolation data is the difference between the real-time position of the industrial robot and the welding point position coordinates in the first welding point interpolation data; The posture interpolation data is the angle coordinate in the first welding point interpolation data.

2. The welding tracking method according to claim 1, characterized in that: Also includes: The set of solder joint interpolation data is sorted.

3. The welding tracking method according to claim 2, characterized in that: Also includes: A fitting process is performed on the set of solder joint interpolation data.

4. The welding tracking method according to claim 1, characterized in that: The communication cycle of the industrial robot is 12 ms, and the predetermined distance is 3 mm.

5. A welding tracking device for executing the welding tracking method according to any one of claims 1 to 4, characterized in that: include: industrial robots; A welding device, provided at the end of the industrial robot; An image acquisition device, provided in the module of the industrial robot, for acquiring the position information and posture information of the welding points at the end of the welding device; A control device connected to the industrial robot and the welding device, used to interpolate the real-time position of the industrial robot based on the welding point position information and posture information Wherein, the image acquisition device includes: a line laser sensor for emitting a fan-shaped laser plane toward an end of the welding device; and An area array industrial camera is used to image the fan-shaped laser plane.

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