Automatic screw welding method and system based on drawing import and visual guidance robot

Abstract

This invention relates to the field of welding technology, and particularly to an automated stud welding method and system based on drawing import and vision-guided robot. The method involves importing workpiece entity information from design drawings to construct a physical digital model; based on the physical digital model, acquiring key information and generating welding points, calculating workpiece offset, and correcting the welding posture; planning the welding path based on the set of welding points; and performing the welding operation based on the welding path and welding posture. Compared with existing technologies, this invention's automated stud welding method and system based on drawing import and vision-guided robot can achieve automatic acquisition of the workpiece's welding position without manual measurement, reducing the number of teaching steps and lowering operational complexity; using machine vision positioning ensures the accuracy of stud position; and by adjusting the welding posture, the welding direction is made perpendicular to the plane where the welding point is located, ensuring that each stud maintains a vertical structure when welded to the workpiece panel, increasing individual stability.

Description

[Technical Field]

[0001] This invention relates to the field of welding technology, and in particular to an automated stud welding method and system based on drawing import and vision-guided robots. [Background Technology]

[0002] Stud welding is a method of welding where one end of a stud contacts the surface of a plate or pipe, an arc is ignited by applying current, and pressure is applied to the stud after the contact surface melts. Stud welding methods include manual welding, die-casting, and laser positioning. Manual welding involves manually measuring the welding points and welding according to those points. Die-casting involves drilling holes for the welding points on a panel of the corresponding specifications, placing the die-casting tool on the workpiece surface, and then aligning the welding torch with the holes. Laser positioning involves pre-teaching all the welding points, calculating the offset of each point using laser positioning, and finally guiding the robot to weld. All these methods have drawbacks. Manual welding relies heavily on human labor; die-casting requires more die-casting as the type of workpiece changes, and the die-casting tool needs to be matched with the workpiece, increasing the complexity of automation; laser positioning requires manual teaching of the workpiece welding points, and adapting too many teaching points when adding new workpieces is time-consuming and labor-intensive. Therefore, researching a fast and accurate automated stud welding method is of great significance. [Summary of the Invention]

[0003] To overcome the above problems, this invention proposes an automated stud welding method and system based on drawing import and vision-guided robots, which can effectively solve the above problems.

[0004] The present invention provides a technical solution to the above-mentioned technical problems: an automatic stud welding method and system based on drawing import and vision-guided robot, comprising the following steps:

[0005] Step S1: Import the workpiece entity information design drawings and construct a solid digital model based on the workpiece entity information design drawings;

[0006] Step S2: Based on the physical digital model, obtain key information and generate welding points, calculate workpiece offset and repair welding posture;

[0007] Step S3: Plan the welding path based on the set of welding points, and perform the welding operation based on the welding path and welding posture during welding.

[0008] Preferably, step S2 includes the following steps:

[0009] Step A2: Based on the physical digital model, obtain the set of welding points A = {(x1, y1), (x2, y2), ..., (x...} i y iThe key point set K = {(x1, y1), (x2, y2), ..., (x...} i y i )};

[0010] Step A3: Set the initial welding posture r so that the straight line of the welding torch head is perpendicular to the plane of the welding area;

[0011] Step A4: Based on the aforementioned key point set K, use a 3D vision device to obtain the set of entity spatial points E = {(x1, y1, z1), (x2, y2, z2), ..., (x...} of the corresponding entities in the geodetic coordinate system. i y i , z i )};

[0012] Step A5: Construct the drawing coordinate system and set any point (x) in the key point set K. i y i Let z = 0, such that the set of entity keypoints K` = {(x1, y1, 0), (x2, y2, 0), ..., (x...} i y i ,0)};

[0013] Step A6: Given the correspondence between the set of entity key points K` and the set of entity spatial points E, let... Let K' and E be the centroids of sets K and E respectively, and N be the size of the sets. Let N be the centroid of the sets K' and E respectively. make Using SVD decomposition, calculate the transformation matrix H = U∑V between the drawing coordinate system and the geodetic coordinate system. T The rotational relation R = VU T Translation relationship

[0014] Step A7: Based on step A5 above, construct a set of welding points A` = {(x1, y1, 0), (x2, y2, 0), ..., (x...} in the drawing coordinate system. i y i ,0)},Combined with the transformation matrix H obtained in step A6 above, the set of welding points Z=H*A` in the geodetic coordinate system is obtained.

[0015] Preferably, step A4 includes the following steps:

[0016] Step A41: Use a high-precision 3D vision sensor to collect data from the workpiece;

[0017] Step A42 involves analyzing and extracting the collected data, which is compatible with multiple feature types.

[0018] Preferably, in step S2, calculating the workpiece offset and correcting the welding posture includes the following steps:

[0019] Step S21: When the position of the workpiece changes, the corresponding spatial point set E` is obtained in the above specific step A4. The two workpiece offsets can be expressed as E` = h*E. The relationship between the changes in the position of the workpiece before and after is obtained by using the above step A6.

[0020] Step S22: When there is a local offset, the robot can be controlled to collect data on the local part of the workpiece, and h2 can be solved using the above step A6. h2 represents the relationship between the changes in the local position of the entity before and after.

[0021] Step S23: Using the change relationship h = h1 divided by h2, combined with the above step A3, a new welding posture r` = h*r is generated.

[0022] An automated stud welding system based on drawing import and vision-guided robot, including the device and control unit;

[0023] The device includes: a high-precision three-dimensional vision sensor, a robot, a stud welding torch, a stud welding machine, a positioner, and a host computer;

[0024] The control unit includes: a preprocessing module for adjusting parameters during the initial installation of the system; a communication module for data interaction with the robot system; a visual positioning module for acquiring spatial information of key points of the workpiece using a three-dimensional vision sensor; a model generation module for generating a digital model of the workpiece; and a process control module for controlling the overall welding process.

[0025] Preferably, the preprocessing module includes robot tool uncalibration and hand-eye parameter calibration.

[0026] Preferably, the communication module uses TCP or IP for communication.

[0027] Preferably, the process control module can customize the welding operation entry point and can operate on any welding point.

[0028] Compared with existing technologies, the automatic stud welding method and system based on drawing import and vision-guided robot of the present invention achieves automatic acquisition of the welding position of the workpiece without manual measurement by importing the design drawings of the workpiece entity, reducing the number of teaching times and reducing the complexity of operation; the use of machine vision positioning ensures the accuracy of stud position; by adjusting the welding posture, the welding direction is made perpendicular to the plane where the welding point is located, which can ensure that each stud maintains a vertical structure when welded to the workpiece panel, increasing individual stability. [Attached Image Description]

[0029] Figure 1This is a flowchart illustrating the steps of the automatic stud welding method based on drawing import and vision-guided robot of the present invention.

Detailed Implementation Methods

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0031] It should be noted that in the embodiments of the present invention, all directional indications (such as up, down, left, right, front, back, etc.) are limited to relative positions on the specified view, rather than absolute positions.

[0032] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] Please see Figure 1 The automatic stud welding method based on drawing import and vision-guided robot of the present invention includes the following steps:

[0034] Step S1: Import the workpiece entity information design drawings, and construct a solid digital model based on the workpiece entity information design drawings. The solid digital model refers to the solid digital model of the workpiece.

[0035] Step S2: Based on the physical digital model, obtain key information and generate welding points, calculate workpiece offset and repair welding posture.

[0036] Step S3: Plan the welding path based on the set of welding points, and perform the welding operation based on the welding path and welding posture during welding.

[0037] The automatic stud welding method based on drawing import and vision-guided robot of the present invention specifically includes the following steps:

[0038] Step A1: Import the drawings designed based on the workpiece entity information, and construct a solid digital model based on the workpiece entity information design drawings.

[0039] Step A2: Based on the physical digital model, obtain the set of welding points A = {(x1, y1), (x2, y2), ..., (x...} i y i The key point set K = {(x1, y1), (x2, y2), ..., (x...}i y i )}.

[0040] Step A3: Set the initial welding posture r so that the straight line of the welding torch head is perpendicular to the plane of the welding area.

[0041] Step A4: Based on the aforementioned key point set K, use a 3D vision device to obtain the set of entity spatial points E = {(x1, y1, z1), (x2, y2, z2), ..., (x...} of the corresponding entities in the geodetic coordinate system. i y i , z i )}.

[0042] Step A5: Construct the drawing coordinate system and set any point (x) in the key point set K. i y i Let z = 0, such that the set of entity keypoints K` = {(x1, y1, 0), (x2, y2, 0), ..., (x...} i y i ,0)}.

[0043] Step A6: Given the correspondence between the set of entity key points K` and the set of entity spatial points E, let... Let K' and E be the centroids of sets K and E respectively, and N be the size of the sets. Let N be the centroid of the sets K' and E respectively. make Using SVD decomposition, calculate the transformation matrix H = U∑V between the drawing coordinate system and the geodetic coordinate system. T The rotational relation R = VU T Translation relationship

[0044] Step A7: Based on step A5 above, construct a set of welding points A` = {(x1, y1, 0), (x2, y2, 0), ..., (x...} in the drawing coordinate system. i y i ,0)},Combined with the transformation matrix H obtained in step A6 above, the set of welding points z=H*A` in the geodetic coordinate system is obtained.

[0045] Step A8: Sort the points in the welding point set z according to the optimal path. During welding, combine the welding point position p (p∈Z) with the welding posture r in step A3 above to perform stud welding and execute the welding operation according to the optimal path.

[0046] Step A4 includes the following steps:

[0047] Step A41: Use a high-precision 3D vision sensor to collect data on the workpiece to improve positioning accuracy.

[0048] Step A42 involves analyzing and extracting the collected data, which is compatible with multiple feature types.

[0049] In step S2, calculating the workpiece offset and correcting the welding posture includes the following steps:

[0050] In step S21, when the position of the workpiece changes, the corresponding spatial point set E' is obtained in the specific step A4 above. The two workpiece offsets can be expressed as E' = h * E. The relationship h1 between the changes in the position of the entity before and after the change is obtained using step A6 above.

[0051] Step S22: When there is a local offset, the robot can be controlled to collect data on the local part of the workpiece and use the above step A6 to solve for h2, where h2 represents the relationship between the changes in the local position of the entity before and after.

[0052] Step S23: Using the change relationship h = h1 / h2 (h1 divided by h2), combined with the above step A3, a new welding posture r` = h*r is generated.

[0053] Step S1 includes step A1.

[0054] Step S2 includes steps A2 to A7.

[0055] Step S3 includes step A8.

[0056] The present invention relates to an automated stud welding system based on drawing import and vision-guided robot, comprising a device and a control unit. The device includes: a high-precision three-dimensional vision sensor, a robot, a stud welding torch, a stud welding machine, a positioner, and a host computer.

[0057] The control unit includes: a preprocessing module for adjusting parameters during initial system installation; a communication module for data interaction with the robot system; a vision positioning module for acquiring spatial information of key points of the workpiece using a three-dimensional vision sensor; a model generation module for generating a digital model of the workpiece; and a process control module for controlling the overall welding process.

[0058] The preprocessing module includes robot tool end calibration and hand-eye parameter calibration.

[0059] The communication module is characterized by using TCP or IP for communication.

[0060] The process control module is characterized by its ability to customize the welding operation entry point and operate on any welding point.

[0061] The specific execution workflow of the automated stud welding system based on drawing import and vision-guided robot of the present invention is as follows:

[0062] 1. Hardware equipment is ready and workpiece loading is complete.

[0063] 2. Select the workpiece type in the control unit and send a start task execution event.

[0064] 3. The robot receives control commands and moves to the designated position, where a high-precision 3D vision sensor collects data. This process is repeated three or more times at different positions.

[0065] 4. The vision positioning module acquires data from a high-precision 3D vision sensor, analyzes and extracts the data, solves for the transformation matrix, calculates the workpiece offset, and corrects the welding posture.

[0066] 5. Furthermore, the transformation matrix is ​​used to generate the stud welding machine positions, and the optimal path in the position set is extracted to generate the welding sequence.

[0067] 6. The control unit sends a stud welding command, and the stud welding machine responds to the command by blowing the stud.

[0068] 7. After the sensor in the stud welding torch senses that the stud is in place, the robot adjusts its welding posture so that the straight line of the welding torch head is perpendicular to the plane of the welding area, and moves to the stud welding point.

[0069] 8. After the robot arrives at the welding point, it triggers a welding signal, and the stud welding machine responds to the command to perform welding.

[0070] 9. After welding is completed, the robot is raised along the straight line of the welding torch head to reduce wear between the welding torch and the stud during the lifting process and extend the service life of the welding torch.

[0071] 10. Complete all welding points in the welding sequence and then end the operation.

[0072] When an unexpected termination occurs during welding, upon restarting, the process control module in the control unit detects the current status, handles the anomaly, and resumes execution. Its main features are:

[0073] When the main structure and position of the robot, workpiece, etc. have not changed, the control unit has cached the welding points of the current workpiece and selects to continue the subsequent process through the process control module.

[0074] When the main structure or position of the robot, workpiece, etc., changes, the process control module in the control unit can select rapid workpiece positioning. The control unit controls the equipment to quickly position the workpiece, generate new welding points, and select to continue executing the subsequent process.

[0075] Compared with existing technologies, the automatic stud welding method and system based on drawing import and vision-guided robot of the present invention achieves automatic acquisition of the welding position of the workpiece without manual measurement by importing the design drawings of the workpiece entity, reducing the number of teaching times and reducing the complexity of operation; the use of machine vision positioning ensures the accuracy of stud position; by adjusting the welding posture, the welding direction is made perpendicular to the plane where the welding point is located, which can ensure that each stud maintains a vertical structure when welded to the workpiece panel, increasing individual stability.

[0076] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any modifications, equivalent substitutions and improvements made within the concept of the present invention should be included within the patent protection scope of the present invention.

Claims

1. An automated stud welding method based on drawing import and vision-guided robot, characterized in that, Includes the following steps: Step S1: Import the workpiece entity information design drawings and construct a solid digital model based on the workpiece entity information design drawings; Step S2: Based on the physical digital model, obtain key information and generate welding points, calculate workpiece offset and repair welding posture; Step S2 includes the following steps: Step A2: Based on the physical digital model, obtain the set of welding points. Key point set ; Step A3: Set the initial welding posture r so that the straight line of the welding torch head is perpendicular to the plane of the welding area; Step A4, based on the above set of key points Using 3D vision equipment to obtain the set of entity spatial points corresponding to the entity in the geodetic coordinate system. ; Step A5: Construct the drawing coordinate system and set the key point set. any point in , let it This makes the set of entity key points ; Step A6, known set of entity key points With the set of physical space points Correspondence, let , Representing sets and set Let N be the centroid of the set, and let N represent the size of the set. , ,make The transformation matrix between the drawing coordinate system and the geodetic coordinate system is calculated using SVD decomposition. , where rotational relationship Translation relationship ; Step A7: Based on step A5 above, construct a set of welding points in the drawing coordinate system. Combined with the transformation matrix obtained in step A6 above The set of welding points Z=H*A` in the geodetic coordinate system is obtained. In step S2, calculating the workpiece offset and correcting the welding posture includes the following steps: Step S21: When the position of the workpiece changes, the corresponding spatial point set E` is obtained in the above specific step A4. The two workpiece offsets can be expressed as E`=h*E. The relationship between the changes in the position of the entity before and after is obtained by using the above step A6. Step S22: When there is a local offset, the robot can be controlled to collect data on the local part of the workpiece, and h2 can be solved using the above step A6. h2 represents the relationship between the changes in the local position of the entity before and after. Step S23: Using the change relationship h=h1 divided by h2, combined with the above step A3, a new welding posture r`=h*r is generated; Step S3: Plan the welding path based on the set of welding points, and perform the welding operation based on the welding path and welding posture during welding.

2. The automated stud welding method based on drawing import and vision-guided robot as described in claim 1, characterized in that, Step A4 includes the following steps: Step A41: Use a high-precision 3D vision sensor to collect data from the workpiece; Step A42 involves analyzing and extracting the collected data, which is compatible with multiple feature types.

3. An automated stud welding system based on drawing import and vision-guided robot, characterized in that, Includes devices and control units; The device includes: a high-precision three-dimensional vision sensor, a robot, a stud welding torch, a stud welding machine, a positioner, and a host computer; The control unit includes: a preprocessing module for adjusting parameters during the initial installation of the system; a communication module for data interaction with the robot system; a visual positioning module for acquiring spatial information of key points of the workpiece using a three-dimensional vision sensor; a model generation module for generating a digital model of the workpiece; and a process control module for controlling the overall welding process.

4. The automated stud welding system based on drawing import and vision-guided robot as described in claim 3, characterized in that, The preprocessing module includes robot tool end calibration and hand-eye parameter calibration.

5. The automated stud welding system based on drawing import and vision-guided robot as described in claim 3, characterized in that, The communication module uses TCP or IP for communication.

6. The automated stud welding system based on drawing import and vision-guided robot as described in claim 3, characterized in that, The process control module can customize the welding operation entry point and can operate on any welding point.

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