阅读说明：本技术 一种检测机器人点焊电极位置补偿功能的装置和方法 (Device and method for detecting position compensation function of robot spot welding electrode ) 是由 李永强 龙梅 赵卯 曹玉文 郭鑫 刘继伟 马贺明 王波 梁海涛 于 2021-06-15 设计创作，主要内容包括：本发明公开了一种检测机器人点焊电极位置补偿功能的装置和方法,属于焊接技术领域,一种检测机器人点焊电极位置补偿功能的装置,包括,包括：检测总成和控制系统,所述检测总成包括设置在点焊电极两侧的摄像头总成和背景总成,所述摄像头总成和背景总成分别与控制系统电连接。本发明提供了一种检测机器人点焊电极位置补偿功能的装置和方法,通过检测在小外力下即可以产生位移的点焊试片在点焊过程中垂直于试片表面方向上的位移曲线,评估点焊示教、机器人系统设置等方面是否正常,而且实现检测效率高、检测结果直观、容易实现和能够全自动检测；而且还能够根据点焊过程中试片位置曲线分析和评估点焊电极磨损补偿功能。(The invention discloses a device and a method for detecting the position compensation function of a robot spot welding electrode, which belong to the technical field of welding, and the device for detecting the position compensation function of the robot spot welding electrode comprises the following components: the detection assembly comprises a camera assembly and a background assembly which are arranged on two sides of the spot welding electrode, and the camera assembly and the background assembly are respectively and electrically connected with the control system. The invention provides a device and a method for detecting a position compensation function of a robot spot welding electrode, which can evaluate whether spot welding teaching, robot system setting and other aspects are normal or not by detecting a displacement curve of a spot welding test piece which can generate displacement under small external force in a direction vertical to the surface of the test piece in a spot welding process, and realize high detection efficiency, intuitive detection result, easy realization and full-automatic detection; and the abrasion compensation function of the spot welding electrode can be analyzed and evaluated according to the position curve of the test piece in the spot welding process.)

1. An apparatus for detecting a function of compensating a position of a spot welding electrode of a robot, comprising: detect assembly (2) and control system (1), detect assembly (2) including setting up camera assembly and background assembly (6) in spot welding electrode (7) both sides, camera assembly and background assembly (6) are connected with control system (1) electricity respectively.

2. The device for detecting the actual pressing position in the robot spot welding process according to claim 1, further comprising a test piece holding mechanism (4), wherein the test piece holding mechanism (4) is adjacent to the spot welding electrode (7), the spot welding test piece (3) is disposed on the test piece holding mechanism (4), and the spot welding test piece (3) is disposed between the moving electrode and the static electrode of the spot welding electrode (7).

3. The apparatus for detecting the actual pressing position in the robot spot welding process according to claim 1 or 2, wherein the camera assembly comprises: the camera comprises a camera (21) and a lens protection cover (22), wherein the lens protection cover (22) is arranged on the camera (21).

4. A device for detection of actual pressing position during robot spot welding according to any of claim 3, characterized in that a filter (2111) is provided between the camera head (21) and the lens protection cover (22).

5. Device for detection of the actual pressing position during a robot spot welding process according to claim 4, characterized in that the spot welding test piece (3) is provided with a marking (31).

6. A device for detection of actual pressing position in robot spot welding process according to claim 4, characterized by further comprising an illumination lamp (5) arranged between the camera assembly and the camera assembly.

7. The device for detecting the actual pressing position in the robot spot welding process according to claim 4, wherein the number of the illuminating lamps (5) is two, and the two illuminating lamps (5) are symmetrically arranged at the upper side and the lower side of the camera assembly.

8. A method for detecting a position compensation function of a robot spot welding electrode is characterized by comprising the following steps:

step S10, obtaining teaching welding point position data;

step S20, obtaining spot welding command data by teaching the position data of the spot welding point, executing the spot welding command data to obtain the image data of the spot welding total process and the image time of the spot welding total process;

step S30, acquiring the specific shooting area (8) of the test piece, and acquiring the specific shooting area position data of each frame of test piece and the shooting time data of each frame of image;

step S40, obtaining a time-varying curve of the test piece position from the specific image area position data of each frame of test piece and the image capturing time data of each frame of image.

9. The method for detecting a function of compensating a position of a spot welding electrode of a robot according to claim 8, wherein the photographing region (8) specific to the test piece comprises: the part mark (31) of the test piece (3) and a pixel band in the direction vertical to the test piece (3) are taken as a shooting area.

10. The method for detecting the function of compensating the position of the spot welding electrode of the robot according to claim 9, wherein the step S10 further comprises acquiring initial image data of the spot welding electrode (7) and the test piece (3).

Technical Field

The invention discloses a device and a method for detecting a position compensation function of a spot welding electrode of a robot, and belongs to the technical field of welding.

Background

Resistance spot welding is one type of resistance welding, is a method of applying electrode pressure to a workpiece through a spot welding electrode and electrifying the workpiece, and performs welding by using resistance heat, and is widely applied to the fields of aerospace, automobiles, home appliance manufacturing and the like. From the aspect of operation, the resistance spot welding operation mainly comprises two types of robot welding and manual welding, wherein the application and the proportion of spot welding carried out by a welding tongs or a workpiece held by a robot are gradually increased.

In the resistance spot welding process, the spot welding electrode can be continuously worn due to reasons such as grinding and deformation, the spot welding tongs can elastically deform under the action of electrode pressure, and further the position of the end face (the part of the spot welding electrode in contact with a workpiece) of the spot welding electrode on the static arm of the spot welding tongs is changed, so that if no correction and compensation measures of the welding position in the direction perpendicular to the surface of the welding spot are adopted, the actual welding position is likely to have a large difference with the specified welding position during teaching of a spot welding robot, and further the problems that the spot welding tongs and parts are mutually broken during spot welding, the robot shakes, equipment wear is aggravated, welding quality is reduced and the like are solved.

The existing technology for ensuring the spot welding position of the robot mainly focuses on a method and a device for ensuring the accuracy of a teaching position and the accuracy of the welding position in the direction vertical to the surface of a welding spot after compensation. However, welding position deviation caused by low teaching quality, improper setting of a robot system, failure in the function of position compensation and the like is common in actual production, and due to the lack of a related detection method, attention is paid to and adjustment is not required when the position deviation is large, which is obviously undesirable. Therefore, a method for judging, detecting or checking whether the spot welding position in the direction substantially perpendicular to the surface of the spot welding point coincides with the taught position is required for judging whether the function and state of the robot spot welding apparatus are normal.

Disclosure of Invention

The invention aims to solve the problem of welding position deviation caused by the reasons that the existing teaching quality is low, a robot system is not arranged properly, the position compensation function does not exert efficacy and the like, and provides a device and a method for detecting the position compensation function of a spot welding electrode of a robot.

The invention aims to solve the problems and is realized by the following technical scheme:

an apparatus for detecting a position compensation function of a robot spot welding electrode, comprising: the detection assembly comprises a camera assembly and a background assembly which are arranged on two sides of the spot welding electrode, and the camera assembly and the background assembly are respectively and electrically connected with the control system.

Preferably, still include test block fixture, test block fixture is adjacent with spot welding electrode, be provided with the spot welding test block on the test block fixture, the spot welding test block sets up between the moving electrode and the static electrode of spot welding electrode.

Preferably, the camera assembly includes: the camera comprises a camera and a lens protective cover, wherein the lens protective cover is arranged on the camera.

Preferably, an optical filter is disposed between the camera and the lens protection cover.

Preferably, the spot welding test piece is provided with a mark.

Preferably, the camera further comprises an illuminating lamp arranged between the camera assembly and the camera assembly.

Preferably, the number of the illuminating lamps is two, and the two illuminating lamps are symmetrically arranged on the upper side and the lower side of the camera assembly.

A method for detecting a position compensation function of a robot spot welding electrode comprises the following steps:

step S10, obtaining teaching welding point position data;

step S20, obtaining spot welding command data by teaching the position data of the spot welding point, executing the spot welding command data to obtain the image data of the spot welding total process and the image time of the spot welding total process;

step S30, acquiring the specific shooting area of the test piece, and acquiring the specific shooting area position data of each frame of test piece and the shooting time data of each frame of image;

step S40, obtaining a time-varying curve of the test piece position from the specific image area position data of each frame of test piece and the image capturing time data of each frame of image.

Preferably, the specimen-specific imaging region includes: the part mark of the test piece and a pixel band vertical to the direction of the test piece are taken as a shooting area.

Preferably, the step S10 further includes acquiring initial spot welding electrode and test piece image data.

The invention has the beneficial effects that:

the invention provides a device and a method for detecting a position compensation function of a robot spot welding electrode, which can evaluate whether spot welding teaching, robot system setting and other aspects are normal or not by detecting a displacement curve of a spot welding test piece which can generate displacement under small external force in a direction vertical to the surface of the test piece in a spot welding process, and realize high detection efficiency, intuitive detection result, easy realization and full-automatic detection; and can also analyze and evaluate the spot welding electrode abrasion compensation function and spot welding clamp elastic deformation compensation function and whether the combination of the spot welding electrode abrasion compensation function and the spot welding clamp elastic deformation compensation function is normal or not according to the test piece position curve in the spot welding process and the programming and teaching personnel capability of the spot welding robot.

Drawings

Fig. 1 is a schematic structural diagram of a device for detecting a position compensation function of a robot spot welding electrode according to the present invention.

Fig. 2 is a schematic structural diagram of the device for detecting the position compensation function of the robot spot welding electrode according to the invention in the direction a.

Fig. 3 is a flowchart of a method for detecting a function of compensating a position of a spot welding electrode of a robot according to the present invention.

Fig. 4 is an initial image of a method of detecting a position compensation function of a robot spot welding electrode according to the present invention.

Fig. 5 is an intermediate process image of a method of detecting a position compensation function of a robot spot welding electrode according to the present invention.

Fig. 6 is an intermediate process image of a method of detecting a position compensation function of a robot spot welding electrode according to the present invention.

Fig. 7 is a schematic diagram of a time-dependent change curve of the test piece position obtained by the method for detecting the position compensation function of the robot spot welding electrode according to the present invention.

Detailed Description

The invention is further illustrated below with reference to the accompanying figures 1-7:

the technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1-2, a first embodiment of the present patent provides, on the basis of the prior art, an apparatus for detecting a position compensation function of a robot spot welding electrode, including: detect assembly 2 and control system 1, detect assembly 2 including installing camera assembly and the background assembly 6 at spot welding electrode 7 both sides, camera assembly and background assembly 6 are connected with control system 1 electricity respectively.

The control system 1 communicates with the spot welding robot system so that both parties can work cooperatively. The camera assembly 2 is used for shooting an image of the spot welding test piece 3 in the spot welding process; the camera assembly 2 is electrically connected with the control system 1, and the control system 1 sends a control signal to control the camera assembly 2 to work. The camera assembly 2 sends the collected images in the spot welding area to the control system 1, and the spot welding test piece 3 is a long strip-shaped single-layer or multi-layer spot welding test piece. The spot welding test piece clamping mechanism 4 is used for clamping one end of the spot welding test piece 3 and keeping the other end of the spot welding test piece 3 suspended, so that when the robot spot welding test piece 3 is suspended, the spot welding test piece 3 is installed between a moving electrode and a static electrode of the spot welding electrode 7, and the suspended part of the spot welding test piece 3 can move along with the spot welding electrode.

The side of the spot welding test piece 3 facing the camera assembly 2 is adhered with an identification 31 which is obviously different from the colors of the shooting background of the camera assembly 2 and the spot welding electrode, and when the spot welding electrode is metal yellow and the background is yellow, the identification adopts white, black, green and other colors.

The two illuminating lamps 5 are arranged between the camera assembly and the camera assembly, the two illuminating lamps 5 are symmetrically arranged on the upper side and the lower side of the camera assembly, and project illuminating light with specific wavelength, such as infrared light with specific wavelength or wavelength combination, to the spot welding test piece;

the illumination lamp 5 receives control signals for controlling the on/off, brightness, and the like of the system 1, and when the illumination lamp 5 is used, the mark 31 is more easily recognized in the image captured by the camera assembly 2.

The mark 31 is made of a retroreflective material, and when the mark 31 is made of the retroreflective material, the brightness of the mark 31 in the image captured by the camera assembly 2 is significantly higher than that of other objects, so that the mark 31 can be recognized more easily.

The camera assembly 2 is composed of a camera 21 and a lens protection cover 22, the control system 1 controls the lens protection cover 22 to open and close, and a lens 211 of the camera 21 in the camera assembly 2 is a telecentric lens. The front of the lens 211 may include a filter 2111 corresponding to the wavelength of the illumination lamp 5, the filter 2111 suppresses light having a wavelength not equal to the wavelength emitted by the illumination lamp 5 from entering the camera 21, and when the filter 2111 is used, the brightness of the mark 31 in the image captured by the camera assembly 2 will be significantly higher than other objects, and thus it is easier to recognize. The background assembly 6 is matched with the camera assembly 2, and the background assembly 6 provides a background for the camera assembly 2.

A method for detecting a function of compensating a spot welding electrode position of a robot is described as follows, as shown in fig. 3:

step S10, obtaining the position data of the teaching welding point and the image data of the initial spot welding electrode and the test piece, the concrete process is as follows:

and grinding the spot welding electrode according to the requirements of the spot welding robot, and finishing other teaching preparation works. If some brand robots may require the use of entirely new electrode teachings, it may be necessary to check the electrode status and replace with a new spot welding electrode before teaching. The camera assembly 2 takes an image as initial spot welding electrode and test piece image data and transmits the image data to the control system 1. And teaching a welding point on the spot welding test piece, and ensuring that the welding point is positioned near the center of the shot image to obtain the position data of the welding point to be taught.

Step S20, spot welding command data is obtained by teaching the position data of the spot welding point, the spot welding command data is executed to obtain the image data of the total spot welding process and the image time of the total spot welding process, and the specific process is as follows:

according to the test purpose, a mode 1 and a mode 2 are selected from the following modes, or the mode 1 and the mode 2 are used simultaneously, wherein the mode 1 is to change parameters such as electrode pressure and the like; mode 2 is to replace or wait for the spot welding electrode to wear out by a certain length. At the moment, the spot welding electrode needs to be ground, and an electrode length detection program such as plate beating is operated according to a robot spot welding electrode length compensation strategy.

The control robot continuously captures an image from the start of the spot welding command to the completion of the pressurization of the spot welding electrode as the image data of the total process of spot welding from the teaching spot welding point position data recorded in step S10, and transmits the image data of the total process of spot welding and the time of the total process of spot welding to the control system 1.

Step S30, obtaining the specific shooting area of the test piece, and obtaining the specific shooting area position data of each frame of the test piece and the shooting time data of each frame of the image, the specific process is as follows:

as shown in fig. 4, in order to increase the frame rate at the time of shooting by the camera 2 and reduce the difficulty of image processing, a specific shooting region 8 is set in S400. Setting the specific imaging area 8 includes selecting a pixel strip including the part mark 31 in the direction perpendicular to the spot welding test piece 3 as the imaging area. The width of the specific imaging region 8 may be set to 1 pixel at the minimum, and the height of the specific imaging region 8 is set to be not less than the fluctuation range of the spot welding test piece position. In this embodiment, the specific shooting area 8 is set in the middle of the image shot by the camera assembly 2, and at this time, perpendicular to the spot welding test piece 3, the initial spot welding electrode and the test piece image data beyond the specific shooting area 8 are deleted, only the spot welding electrode and the spot welding test piece 3 are left, the specific shooting area position data and the specific shooting time data of each frame of test piece are obtained through the total image time of the spot welding process and the total image data of the spot welding process, and the image shot after the specific shooting area 8 is activated is shown in fig. 5.

The control system 1 processes the received image and analyzes the position of the marker 31 frame by frame as the position of the spot welding test piece. Since the color and/or brightness of the mark 31 has a distinct region from the image of only the spot welding electrode and the spot welding test piece 3, the image of only the spot welding electrode and the spot welding test piece 3 can be binarized based on the color and/or brightness of the mark 31, and the processed image will only include the mark 31, and at this time, the photographed image is as shown in fig. 6. The center of gravity or the center of the marker 31 in the processed image is calculated frame by frame, the center of gravity or the center of the white region in fig. 6 is calculated, and the calculated center of gravity or the center is set as the position of the marker 31.

In step S40, a time-varying curve of the test piece position is obtained from the specific imaging area position data of each frame of test piece and the imaging time data of each frame of image, as shown in fig. 7.

While embodiments of the invention have been disclosed above, it is not intended to be limited to the uses set forth in the specification and examples. It can be applied to all kinds of fields suitable for the present invention. Additional modifications will readily occur to those skilled in the art. It is therefore intended that the invention not be limited to the exact details and illustrations described and illustrated herein, but fall within the scope of the appended claims and equivalents thereof.