A device and method for measuring the size of a weld and correcting parameters of a weld seam tracking

Abstract

The application discloses a kind of welding spot size measurement and welding seam tracking parameter synchronous correction device and method, the device includes welding spot size initiative measurement module, structured light welding seam tracking sensing module, synchronous correction module.The method is by miniature CCD camera to the welding spot in front of tracking welding seam is photographed and is transmitted to welding spot image processor, obtains the size of welding spot, control computer is compared with preset welding spot size, obtains the difference with preset welding spot size and is transmitted to synchronous corrector, synchronous corrector will according to the size of difference with preset welding spot size, the size of preset welding spot is corrected in real time, the welding spot size initiative measurement and the method of structured light welding seam tracking parameter synchronous correction of the present application, solve the problem that laser welding seam tracking deviates when welding when point solid welding spot size, reduce the influence of point solid welding spot to welding seam tracking precision, to improve the welding quality of welding seam automatic intelligent welding.

Description

Technical Field

[0001] This invention belongs to the field of automated welding, and mainly relates to a device and method for synchronously correcting weld spot size measurement and weld seam tracking parameters. Background Technology

[0002] In the welding field, the emergence of weld seam tracking technology has greatly improved welding efficiency and quality. Currently, robot-based weld seam tracking technology is the most widely used. A structured light emitter emits laser stripes that illuminate the weld seam surface. A vision sensor captures the laser stripe image, and image processing extracts weld seam feature points to determine the actual weld seam position, which is then fed back to the robot for real-time adjustment of the welding trajectory. However, in the actual welding process, the assembled workpiece undergoes a spot-fixing process to secure it, leaving weld points on the weld seam. These weld points can obscure the weld seam's feature points, making it difficult to accurately identify the actual weld seam position during tracking, leading to tracking deviations. Currently, when encountering weld points during weld seam tracking, the main solution is to set weld point shape parameters in the sensor parameters to address tracking errors. However, since the spot-fixing process is done manually by workers, the shape and size of each weld point are difficult to guarantee consistency. Therefore, when the shape parameters of some weld points are outside the preset parameters, the weld seam position still cannot be accurately identified during tracking. Therefore, the large deviation and poor tracking accuracy when encountering weld points during weld seam tracking is an urgent problem that needs to be solved.

[0003] The patent "Robot Weld Seam Tracking System and Control Method Based on Structured Light Sensor" (application number CN110681950 A) discloses a robot weld seam tracking method. This method projects structured light onto the weld seam surface and extracts weld seam feature points from the structured light stripes to achieve weld seam tracking. However, it does not address the method for tracking weld seam feature points on workpieces with weld points, thus failing to guarantee the accuracy of weld seam tracking and exhibiting certain limitations. The patent "A Multifunctional Binocular Vision Sensor for Welding Robots and Calibration Method" (application number 200710037890.3) discloses a multifunctional binocular vision sensor. This method distributes two vision sensors on the front and rear sides of the welding torch to achieve weld seam tracking and molten pool monitoring respectively. However, this method does not address the weld seam tracking of workpieces with weld points, failing to address the influence of weld points on the weld seam tracking process and exhibiting certain limitations. Summary of the Invention

[0004] To address the issues of tracking deviation and poor tracking accuracy that occur when using structured light weld seam tracking technology to track workpieces with weld points, this invention provides a device and method for synchronously correcting weld point size measurement and weld seam tracking parameters, which can effectively solve the above problems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A device for synchronously correcting weld spot size measurement and weld seam tracking parameters is provided, comprising an active weld spot size measurement module, a structured light weld seam tracking sensing module, and a synchronous correction module. The active weld spot size measurement module specifically includes a miniature CCD camera integrated on the circumference of the welding torch, used to measure the size of weld spots on the workpiece. The miniature CCD camera is connected to a weld spot image processor, which is connected to a control computer. The structured light weld seam tracking sensing module specifically includes a laser stripe generator and a bevel vision camera integrated and fixed on a fixture, connected to a bevel image processor, which is also connected to the control computer. A robot control cabinet controls the activation and sensing control of the structured light weld seam tracking sensing module via a synchronous corrector. The synchronous correction module specifically includes a synchronous corrector connected to the control computer and also connected to the robot control cabinet. The robot control cabinet controls the activation and synchronous measurement of the weld spot image processor and the bevel image processor via the synchronous corrector.

[0007] Furthermore, a miniature CCD camera is integrated on the circumference of the welding torch, with an angle adjustment range of 20–70° relative to the welding torch axis.

[0008] Furthermore, miniature CCD cameras are small in size, with lens diameters ranging from 3 to 10 mm.

[0009] Furthermore, the weld size is measured simultaneously by a miniature CCD camera and a bevel gauge and a bevel vision camera, and the weld tracking settings are corrected in real time.

[0010] Furthermore, a method for synchronously correcting weld spot size measurement and weld seam tracking parameters is provided, specifically including the following steps:

[0011] 1) After the length and width of the weld point are preset on the control computer, welding begins. The miniature CCD camera captures the shape of the weld point in front of the laser stripe, and the bevel vision camera captures the laser stripe image at the weld bevel.

[0012] 2) The miniature CCD camera transmits the captured solder joint shape to the solder joint image processor. The solder joint image processor extracts the solder joint length and width and transmits them to the control computer. The control computer compares the length and width with the preset solder joint length and width, calculates the difference between the two, and transmits it to the synchronous corrector. The synchronous corrector corrects the length and width of the preset solder joint in real time.

[0013] 3) When the laser stripe illuminates the bevel of the corrected weld point, the bevel image processor will extract the weld feature points to obtain the position of the weld and transmit it to the robot control cabinet. The robot control cabinet will then correct the movement of the welding torch in real time.

[0014] Furthermore, the miniature CCD camera and the bevel vision camera take pictures simultaneously, and the area being captured is in front of the direction in which the welding torch moves. The area captured by the miniature CCD camera is located 10 to 30 mm in front of the laser stripes illuminating the weld surface.

[0015] Furthermore, the synchronous straightener's correction of the preset solder joint size specifically includes:

[0016] The length d of the solder joint l and d w When the difference between the width and the preset solder joint length and width is within 10%, the length and width of the solder joint preset by the computer software will not be corrected within the allowable error range.

[0017] The length d of the solder joint l and width d w When the difference between the length and width of the weld point and the preset weld point is greater than 10%, the length and width of the weld point preset by the computer software are corrected, and then the running trajectory of the corresponding robot welding gun is corrected for the corresponding position difference by the synchronous corrector.

[0018] Compared with existing technologies, the present invention has the following advantages: 1. Compared with traditional weld seam tracking methods, the present invention uses two cameras to obtain image information of the weld seam and the tack weld point respectively, and fuses the information. By correcting the weld point size, it can effectively solve the problem of poor tracking accuracy when encountering a weld point; 2. The system has the advantages of flexible structure, high degree of automation, and high tracking accuracy, and can be widely used in actual industrial production; 3. It can be applied to various types of weld seams and processes, and can be widely used in robotic automated welding. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a device for synchronously correcting weld spot size measurement and weld seam tracking parameters.

[0020] Figure 2 This is a schematic diagram of the solder joint dimensions.

[0021] Figure 3 This is a flowchart for the synchronous correction of weld spot size measurement and weld seam tracking parameters.

[0022] In the figure, 1 is the workpiece, 2 is the welding torch, 3 is the miniature CCD camera, 4 is the fixture, 5 is the weld point image processor, 6 is the synchronous corrector, 7 is the control computer, 8 is the robot control cabinet, 9 is the bevel image processor, 10 is the laser stripe generator, 11 is the bevel vision camera, and 12 is the weld point. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solution of the present invention, a device and method for synchronously correcting weld spot size measurement and weld seam tracking parameters provided by the present invention will be described in detail below with reference to the accompanying drawings. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] The equipment used is as follows: MOTOMAN MH6 Yaskawa arc welding robot, DX100 robot control cabinet, CMT-Advance 4000 welding machine, optoNCDT 1710BL bevel vision image sensor, and FT-G2F400 miniature CCD camera.

[0025] Combination Figure 1 This invention provides a device for synchronously correcting weld spot size measurement and weld seam tracking parameters, mainly composed of three modules: an active weld spot measurement module, a structured light weld seam tracking sensing module, and a synchronous correction module. Specifically, it includes: a Yaskawa robot control cabinet, a MIG welding torch, a miniature CCD camera, a bevel vision camera, a weld spot image processor, a bevel image processor, a laser stripe generator, a synchronous corrector, a control computer, weld seam tracking image software, a welding torch fixture, signal sensing lines, and a USB data connection cable.

[0026] The active weld spot size measurement module is mainly used to photograph the tack welds in the weld seam and obtain the weld spot size data. Specifically, it includes: integrating a miniature CCD camera next to the pipe supplying the shielding gas around the welding torch via a movable clamp; adjusting the angle of the movable clamp allows for adjustment of the angle between the miniature CCD camera and the welding torch axis, with an adjustment range between 20° and 70°; the selected miniature CCD camera is small in size, with a lens diameter between 3 and 10 mm. The miniature CCD camera's signal sensor line is integrated inside the welding torch, and its output is connected to the weld spot image processor. The miniature CCD camera is used to photograph the morphology of the tack welds in the workpiece and outputs the captured image of the tack weld morphology to the weld spot image processor via the signal sensor line.

[0027] The structured light weld seam tracking sensor module is mainly used to extract weld seam feature points and obtain real-time weld seam position data. Specifically, it integrates a laser stripe generator and a bevel vision camera into a single device, which is then fixed to the welding torch using a welding torch clamp. The bevel vision camera is connected to a bevel image processor via a signal sensing line, transmitting the captured laser stripe image of the bevel to the image processor. The bevel image processor is connected to a control computer via a USB data cable, transmitting the weld seam feature point position data obtained from the image processor to the control computer. The integrated structured light weld seam tracking sensor module is connected to a synchronization corrector via a signal sensing line. The synchronization corrector is connected to the robot control cabinet via the same signal sensing line. The robot control cabinet sends signals to the synchronization corrector, which then transmits the signals to the structured light weld seam tracking sensor module, thereby controlling its activation and sensing operation.

[0028] The synchronous correction module is mainly used for correcting the weld joint dimensions and controlling the activation and sensing of the sensors. Specifically, it includes: a control computer connected to the synchronous corrector via a USB data cable, and the synchronous corrector connected to the robot control cabinet via a signal sensing line. The robot control cabinet sends signals to the synchronous corrector, which controls the activation and synchronous measurement of the weld joint image processor and the bevel image processor.

[0029] Example 1

[0030] Using the device of the above invention, a method for simultaneously measuring the dimensions of I-groove butt weld joints of 3mm thick 5A06 aluminum alloy and simultaneously correcting weld tracking parameters is implemented, combined with... Figures 2-3 The specific steps are as follows:

[0031] 1) First, set the sensing parameters of the structured light weld tracking sensor module and the relevant parameters of the weld bevel on the weld tracking image processing software on the control computer. Specific settings include: 5 weld tracking points, 80% laser intensity, automatic volume integration sensing, 3mm plate thickness, I-bevel type, 0.5-1mm butt weld bevel gap, and the length and width of the weld point are preset to 6mm and 4mm, respectively.

[0032] 2) First, teach the robot the approximate welding trajectory based on the position of the weld seam on the workpiece, mainly by teaching the welding start reference point, welding midpoint and welding end reference point, and set the relevant welding process parameters.

[0033] 3) Start the robot and welding machine to perform welding. When the robot moves to the welding start reference point, the robot control cabinet sends control commands to the synchronous corrector and welding machine to start the welding machine and simultaneously control the start of the structured light weld seam tracking sensor module, miniature CCD camera, weld point image processor and bevel image processor through the synchronous corrector.

[0034] 4) The miniature CCD camera and the bevel vision camera simultaneously capture images in the area in front of the welding torch's forward direction. The miniature CCD camera's image area is located 10-30mm in front of the laser stripes illuminating the weld surface. When the weld joint size is small, the miniature CCD camera transmits the captured weld joint shape to the weld joint image processor. The weld joint image processor extracts the weld joint length and width as 6.2mm and 4.3mm, respectively, and transmits them to the control computer. The control computer compares these dimensions with preset weld joint lengths and widths, determining that the difference is less than 10%. Within the allowable error range, the synchronous corrector does not correct the preset weld joint dimensions. When the robot moves to the weld joint, the bevel image processor extracts the weld joint feature points to determine the weld joint's position, which is then transmitted to the robot control cabinet. The robot control cabinet performs real-time correction of the welding torch's movement. When the size of the solder joint is large, the miniature CCD camera transmits the image of the solder joint to the solder joint image processor. The solder joint image processor extracts the length and width of the solder joint as 8mm and 6mm respectively, and transmits them to the control computer. The control computer compares the length and width with the preset solder joint length and width and finds that the difference is 2mm, which is greater than 10%. The synchronous corrector will correct the length and width of the preset solder joint to 8mm and 6mm respectively in real time. When the robot moves to the solder joint, the synchronous corrector transmits the 2mm difference in length and width of the solder joint to the robot control cabinet. The robot control cabinet sends motion control commands to the welding gun, offsetting the original trajectory by 2mm in length and width respectively.

[0035] 5) When the robot moves to the welding end reference point, the robot control cabinet simultaneously sends control commands to the welding machine and the synchronous corrector to stop welding and simultaneously control the stop of the structured light weld seam tracking sensor module, miniature CCD camera, weld point image processor and bevel image processor through the synchronous corrector.

[0036] By measuring the weld spot size and simultaneously correcting the weld seam tracking parameters, when welding a 3mm thick 5A06 aluminum alloy I-groove butt weld, the welding torch can always remain in the center of the butt weld when passing through weld spots of different sizes in the butt weld.

[0037] Example 2

[0038] Using the apparatus of the above invention, a method for simultaneously measuring the weld spot size and correcting weld tracking parameters of lap welds in 6mm thick Q234 carbon steel and 10mm thick Q345 carbon steel is implemented, combined with... Figures 2-3 The specific steps are as follows:

[0039] 1) First, set the sensing parameters of the structured light weld tracking sensor module and the relevant parameters of the weld bevel on the weld tracking image processing software on the control computer. The number of weld tracking points is 5, the laser intensity is 90%, the sensing method is automatic volume integration sensing, the joint type is lap joint, the thickness of the upper lap plate is 6mm, the thickness of the lower plate is 10mm, the gap between the upper and lower plates is 0-3mm, the lap method is left lap, and the length and width of the weld point are preset to 7mm and 5mm respectively.

[0040] 2) First, teach the robot the approximate welding trajectory based on the position of the weld seam on the workpiece, mainly by teaching the welding start reference point, welding midpoint and welding end reference point, and set the relevant welding process parameters.

[0041] 3) Start the robot and welding machine to perform welding. When the robot moves to the welding start reference point, the robot control cabinet sends control commands to the synchronous corrector and welding machine to start the welding machine and simultaneously control the start of the structured light weld seam tracking sensor module, miniature CCD camera, weld point image processor and bevel image processor through the synchronous corrector.

[0042] 4) The miniature CCD camera and the bevel vision camera simultaneously capture images in the area in front of the welding torch's forward direction. The miniature CCD camera's image area is located 10-30mm in front of the laser stripes illuminating the weld surface. When the weld joint size is small, the miniature CCD camera transmits the captured weld joint shape to the weld joint image processor. The weld joint image processor extracts the weld joint length and width as 7.2mm and 5.3mm, respectively, and transmits them to the control computer. The control computer compares these with preset weld joint length and width, determining that the difference is less than 10%. Within the allowable error range, the synchronous corrector does not correct the preset weld joint size. When the robot moves to the weld joint, the bevel image processor extracts the weld joint feature points to obtain the weld joint position, which is then transmitted to the robot control cabinet. The robot control cabinet performs real-time correction of the welding torch movement. When the weld joint is large, the miniature CCD camera transmits the weld joint shape to the weld joint image processor. The weld joint image processor extracts the weld joint length and width as 10mm and 7mm respectively, and transmits them to the control computer. The control computer compares the weld joint length and width with the preset weld joint length and width, and finds that the difference is 3mm in length and 2mm in width, which is greater than 10%. The synchronous corrector will correct the length and width of the preset weld joint to 10mm and 7mm respectively in real time. When the robot moves to the weld joint, the synchronous corrector transmits the difference of 3mm in length and 2mm in width to the robot control cabinet. The robot control cabinet sends motion control commands to the welding gun, which offsets the original trajectory by 3mm in length and 2mm in width.

[0043] 5) When the robot moves to the welding end reference point, the robot control cabinet simultaneously sends control commands to the welding machine and the synchronous corrector to stop welding and simultaneously control the stop of the structured light weld seam tracking sensor module, miniature CCD camera, weld point image processor and bevel image processor through the synchronous corrector.

[0044] By measuring the weld spot size and simultaneously correcting the weld seam tracking parameters, when welding lap welds of 6mm thick Q234 carbon steel and 10mm thick Q345 carbon steel, the welding torch can always remain in the center of the lap weld when passing through weld spots of different sizes in the lap weld.

Claims

1. A device for measuring the size of a weld spot and correcting parameters of a weld seam tracking, characterized in that: It comprises a welding spot size active measurement module, a structured light welding seam tracking sensor module and a synchronous correction module. The welding spot size active measurement module specifically comprises a micro-CCD camera (3) integrated at the circumference of the welding torch, which is used to measure the size of the welding spot (12) of the welding seam on the workpiece (1), the micro-CCD camera (3) is connected with a welding spot image processor (5), and the welding spot image processor (5) is connected with a control computer (7); The structured light welding seam tracking sensor module specifically comprises a laser stripe generator (10) and a groove visual camera (11) integrated and fixed on the fixture (4) and connected with a groove image processor (9), the groove image processor (9) is connected with the control computer (7) at the same time, and the robot control cabinet (8) controls the start and sensing control of the structured light welding seam tracking sensor module through the synchronous corrector (6); The synchronous correction module specifically comprises that the synchronous corrector (6) is connected with the control computer (7), and the synchronous corrector (6) is connected with the robot control cabinet (8) at the same time, and the robot control cabinet (8) controls the start and synchronous measurement of the welding spot image processor (5) and the groove image processor (9) through the synchronous corrector (6); The micro-CCD camera is integrated at the circumference of the welding torch, and the angle adjustment range between the micro-CCD camera and the axis of the welding torch is 20-70°. The micro-CCD camera has a small volume, and the lens diameter is 3-10 mm. The welding spot size measurement micro-CCD camera and the groove size measurement CCD visual camera are used for synchronous measurement, and the welding seam tracking setting parameters are corrected in real time.

2. A method of synchronous correction based on the device of claim 1, characterized in that: Specifically, the following steps are included: 1) The length of the weld is pre-set on the control computer d l and width d w The welding is started after that, the micro-CCD camera takes the picture of the weld shape in front of the laser stripe, and the groove visual camera takes the picture of the laser stripe image at the groove of the weld. 2) The micro-CCD camera transmits the photographed welding spot morphology to the welding spot image processor, the welding spot image processor extracts the length and width of the welding spot and transmits them to the control computer, the control computer compares the length and width with the preset welding spot length and width, obtains the difference value and transmits it to the synchronous corrector, and the synchronous corrector corrects the length and width of the preset welding spot in real time; 3) When the laser stripe is irradiated to the groove of the corrected welding spot, the groove image processor extracts the welding seam feature points to obtain the position of the welding seam and transmits it to the robot control cabinet, and the robot control cabinet performs real-time deviation correction on the welding torch movement.

3. The method of claim 2, wherein: The micro-CCD camera and the groove visual camera are used for synchronous shooting, and the shooting area is in front of the advancing direction of the welding torch, and the shooting area of the micro-CCD camera is located at 10-30 mm in front of the laser stripe irradiated to the welding seam surface.

4. The method of claim 2, wherein: The synchronous correction of the preset welding spot size specifically comprises: Length of the weld d l and width d w When the length and width of the weld differ from the preset length and width of the weld by within 10%, it is within the allowable error range, and the length and width of the weld preset by the computer software are not corrected. Length of the weld d l And width d w When the difference between the preset length and width of the weld is greater than 10%, the length and width of the preset weld of the computer software are corrected, and then the running track of the corresponding robot welding gun is corrected by the corresponding position difference through the synchronous corrector.

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