A laser welding robot with a weld seam recognition function and a working method thereof

Abstract

This invention relates to a laser welding robot with weld seam recognition function and its working method, including a weld seam recognition mechanism installed at the end of a six-axis robotic arm, on which a laser welding head is mounted; the weld seam recognition mechanism includes a top plate connected to the end of the six-axis robotic arm, and several support arms are arranged at equal angles on the outer side of the top plate, with the bottom ends of the support arms connected to the bottom plate, the bottom plate being connected to the top of the laser welding head, and the bottom side of the top plate being connected to a fixed plate via a connecting arm, with a rotating ring rotatably mounted on the outer side of the fixed plate; through multiple independently deployable area array cameras, a stable multi-view observation ring is formed around the laser welding head, and during the scanning phase, the area array cameras can synchronously or sequentially acquire weld seam images from different directions, effectively solving the recognition problems caused by blind spots, workpiece occlusion, or uneven lighting of a single camera, and is adept at handling three-dimensional spatial curved weld seams, fillet weld seams, and weld seams with obstacles.

Description

Technical Field

[0001] This invention relates to the field of industrial robots and automated welding technology, and in particular to a laser welding robot with weld seam recognition function and its working method. Background Technology

[0002] In the field of automated laser welding, accurate identification and tracking of weld seams are prerequisites for achieving high-quality welding. Traditional weld seam identification often uses fixed monocular or binocular vision sensors, which have fixed fields of view and angles. Their identification capabilities are limited when dealing with spatially curved weld seams, obscured weld seams, or workpieces with changing postures, making them prone to missed detections or misjudgments.

[0003] Existing vision systems are often rigidly connected to the welding torch (laser welding head) or have a fixed relative position, making it difficult to perform rapid and comprehensive pre-scanning of the weld before welding, and also unable to flexibly adjust the observation angle without affecting the welding space. Although some solutions attempt to use additional small robots or swinging mechanisms to carry cameras, the structure is complex, increases the risk of motion interference, and makes it difficult to achieve multi-camera collaborative observation. Summary of the Invention

[0004] The present invention addresses the problem of providing a laser welding robot with weld seam recognition function and its working method, thereby solving the technical problems of limited field of view, poor flexibility, and difficulty in rapidly and comprehensively pre-scanning complex spatial weld seams in existing weld seam recognition systems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A laser welding robot with weld seam recognition function includes a weld seam recognition mechanism installed at the end of a six-axis robotic arm, on which a laser welding head is mounted. The weld seam recognition mechanism includes a top plate connected to the end of the six-axis robotic arm. Several support arms are arranged at equal angles on the outer side of the top plate, and the bottom ends of the support arms are connected to the bottom plate. The bottom plate is connected to the top end of the laser welding head. The bottom side of the top plate is connected to a fixed plate via a connecting arm. A rotating ring is rotatably mounted on the outer side of the fixed plate. Several linear rails are arranged at equal angles on the fixed plate and the rotating ring. A first slider and a second slider are slidably mounted on the linear rails. A fixed seat is mounted on the outer side of the second slider. The fixed seat is rotatably connected to the top end of a first rotating arm. The bottom end of the first rotating arm is rotatably connected to the top ends of two second rotating arms. An area scan camera is rotatably mounted between the bottom ends of the two second rotating arms.

[0006] Preferably, a stop is provided at the outer end of the linear rail of the rotating ring, the first slider slides on the linear rail of the fixed plate, and the second slider slides on the linear rails of the fixed plate and the rotating ring.

[0007] Preferably, the fixed plate has several straight grooves parallel to the linear rail at equal angles, a turntable is rotatably mounted on the bottom side of the fixed plate, and the turntable has several arc-shaped grooves at equal angles. The first slider is equipped with a guide rod that passes through the straight grooves and arc-shaped grooves.

[0008] Preferably, a first motor is installed at the center of the top of the fixed disk, and the output end of the first motor is connected to the turntable.

[0009] Preferably, a second motor is installed on the top side of the fixed disk, a gear groove is opened on the turntable, the output end of the second motor is installed with rotating teeth in the gear groove, and an inner ring tooth is provided on the bottom side of the rotating ring, and the inner ring tooth meshes with the rotating tooth.

[0010] Preferably, an electromagnet is installed inside the first slider, a permanent magnet is installed inside the second slider, and a plurality of arc-shaped limiting rings are provided at equal angles on the outer side of the top of the fixed disk, and the arc-shaped limiting rings are staggered with the first slider.

[0011] Preferably, a first motor is installed on the fixed base, the output end of the first motor is connected to the first rotating arm, and the first rotating arm is provided with a camera storage slot for accommodating an area array camera.

[0012] Preferably, a second motor is installed on the outer side of the top of the second rotating arm, and the output end of the second motor is connected to the bottom end of the first rotating arm.

[0013] Preferably, a third motor is installed at the bottom end of the second rotating arm, and the output end of the third motor is connected to the area scan camera.

[0014] A working method for a laser welding robot with weld seam recognition function, the specific operation steps of which are as follows: Step 1: When identifying the weld seam, the first motor installed at the center of the top side of the fixed plate is started, driving the turntable connected to its output end to rotate. The rotation of the turntable is converted into the radial linear motion of all the first sliders along their respective linear rails through the guiding effect of the arc groove, pushing them outward. At this time, the electromagnet installed in the first slider is energized, generating magnetic force, attracting the permanent magnet installed in the second slider. The second slider and the first slider are magnetically locked together and move outward together with the first slider until the second slider is on the rotating ring. The first motor drives the first rotating arm to rotate downward to a vertical position, the second motor drives the second rotating arm to rotate downward, and the third motor drives the area array camera to rotate to the working posture aligned with the workpiece. Multiple area array cameras form a stable multi-view observation ring around the laser welding head. Step 2: When the electromagnet is de-energized and the magnetic force disappears, the magnetic lock between the second slider and the first slider is released. The second motor installed on the top side of the fixed plate starts and drives the rotating teeth at its output end to rotate. The rotation of the rotating ring is achieved through the meshing inner ring teeth. The rotation of the rotating ring drives the second sliders on all the rotating rings to rotate. The second sliders stop when they are close to the support arm. The entire vision arm assembly fixed on the second slider moves synchronously in a circumferential direction. During the process of circling, the area scan camera continuously captures the weld seam area below at a high frame rate, realizing continuous, multi-angle scanning of the weld seam in a spiral or circular manner. Step 3: After scanning and recognition are completed, the rotating ring resets, the electromagnet is re-energized, attracting the second slider. The motors of each joint drive the vision arm assembly to fold and store. Finally, the first motor reverses, driving all sliders to slide inward along the straight rail back to their initial positions. The entire weld recognition mechanism returns to its stored state, ready for welding or movement.

[0015] The beneficial effects of this invention are: By using multiple independently deployable area array cameras, a stable multi-view observation ring is formed around the laser welding head. During the scanning phase, the area array cameras can acquire weld images synchronously or sequentially from different directions, effectively solving the recognition problem caused by blind spots, workpiece occlusion, or uneven lighting of a single camera. It is good at handling three-dimensional curved welds, fillet welds, and welds with obstacles. The unique slider-rotor transmission mechanism enables all vision arm groups to simultaneously expand radially to broaden the observation range, and to perform circumferential rotation scanning around the weld head axis as a whole. This allows for continuous, multi-angle acquisition of panoramic image sequences of the weld seam, providing richer contextual information and higher-precision 3D reconstruction data compared to static shooting, greatly improving the robustness and positioning accuracy of the recognition algorithm. During work breaks or when the robot moves, all vision arm assemblies are folded up, and the area scan camera is stored in a specially designed camera storage slot. The entire recognition mechanism is retracted into a compact space above the laser welding head, becoming an integral part of the laser welding head. This minimizes the external size and avoids the risk of collisions with workpieces and fixtures in narrow spaces or dense workstations. Driven by the first motor, the turntable is rapidly and smoothly extended radially using the arc-shaped groove guide rod mechanism, simultaneously and smoothly extending all the first sliders and the second sliders locked by magnetic force. The vision arm assembly then unfolds. By employing the magnetic coupling and separation mechanism of electromagnets and permanent magnets, the intelligent switching between the radial drive mode of the first slider and the circumferential drive mode of the second slider is realized. When unfolding, they are attracted together to achieve overall extension; when scanning, they are separated, allowing the rotating ring to drive the vision arm assembly to rotate independently. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the weld seam identification mechanism of the present invention; Figure 3 This is a schematic diagram of the internal structure of the weld seam identification mechanism of the present invention; Figure 4 This is a schematic diagram of the turntable mounting structure of the present invention; Figure 5 This is a schematic diagram of the internal structure of the first and second sliders of the present invention.

[0017] Legend: 1. Six-axis robotic arm; 2. Weld seam recognition mechanism; 3. Laser welding head; 4. Top plate; 5. Support arm; 6. Base plate; 7. Connecting arm; 8. Fixed plate; 9. Rotary ring; 10. Linear groove; 11. Linear rail; 12. First slider; 13. Second slider; 14. Fixed base; 15. First rotating arm; 16. Second rotating arm; 17. Area array camera; 18. First motor; 19. Turntable; 20. Arc-shaped groove; 21. Guide rod; 22. Gear groove; 23. Second motor; 24. Rotary gear; 25. Inner ring gear; 26. Electromagnet; 27. Permanent magnet; 28. First motor; 29. ​​Second motor; 30. Third motor; 31. Camera storage slot; 32. Arc-shaped limit stop ring. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Specific implementation examples are given below.

[0020] See Figures 1-5A laser welding robot with weld seam recognition function includes a weld seam recognition mechanism 2 installed at the end of a six-axis robotic arm 1, and a laser welding head 3 mounted on the weld seam recognition mechanism 2. The weld seam recognition mechanism 2 includes a top plate 4 connected to the end of the six-axis robotic arm 1. Several support arms 5 are arranged at equal angles on the outer side of the top plate 4, and the bottom ends of the support arms 5 are connected to a base plate 6. The base plate 6 is connected to the top end of the laser welding head 3. The truss structure formed by the support arms 5 firmly connects the top plate 4 and the base plate 6, providing stable support for the laser welding head 3, and forming a hollow area to accommodate the subsequent recognition mechanism, resulting in high space utilization. The bottom side of the top plate 4 is connected to a fixed plate 8 through a connecting arm 7. A rotating ring 9 is rotatably mounted on the outer side of the fixed plate 8. Several linear rails 11 are arranged at equal angles on the fixed plate 8 and the rotating ring 9. A first slider 12 and a second slider 1 are slidably mounted on the linear rails 11. 3. A stop is provided at the outer end of the linear rail 11 of the rotating ring 9. The first slider 12 slides on the linear rail 11 of the fixed plate 8, and the second slider 13 slides on the linear rail 11 of the fixed plate 8 and the rotating ring 9. The fixed plate 8 has several linear grooves 10 parallel to the linear rail 11 at equal angles. A turntable 19 is rotatably installed on the bottom side of the fixed plate 8, and several arc grooves 20 are opened at equal angles on the turntable 19. A guide rod 21 that passes through the linear grooves 10 and arc grooves 20 is installed on the first slider 12. A first motor 18 is installed at the top center of the fixed plate 8. The output end of the first motor 18 is connected to the turntable 19. The first motor 18 drives the turntable 19 to rotate. Through the forced constraint of the guide rod 21 by the arc grooves 20, the rotational motion is converted into radial linear motion of all the first sliders 12 in strict synchronization, so as to realize the rapid and neat unfolding of the recognition unit from the center to the periphery.

[0021] A second motor 23 is mounted on the top side of the fixed disk 8. A gear groove 22 is provided on the turntable 19. The output end of the second motor 23 is located in the gear groove 22 and a rotating tooth 24 is installed. An inner ring tooth 25 is provided on the bottom side of the rotating ring 9, and the inner ring tooth 25 meshes with the rotating tooth 24. An electromagnet 26 is installed in the first slider 12, and a permanent magnet 27 is installed in the second slider 13. Several arc-shaped limiting rings 32 are arranged at equal angles on the outer side of the top of the fixed disk 8, and the arc-shaped limiting rings 32 are staggered with the first slider 12. The two motors 23 mesh with the gears 24 and 25 of the inner ring gear to drive the rotating ring 9 and all the second sliders 13 to achieve smooth and synchronous circumferential rotation, providing power for spiral scanning. The electromagnet 26 in the first slider 12 and the permanent magnet 27 in the second slider 13 form a controllable magnetic coupling mechanism; they are attracted when energized to achieve radial expansion linkage; they are separated when de-energized, allowing the rotating ring 9 to rotate independently for scanning, realizing intelligent and contactless switching of working modes and avoiding complex mechanical clutches.

[0022] A fixed base 14 is mounted on the outer side of the second slider 13. The fixed base 14 is rotatably connected to the top end of the first rotating arm 15. The bottom end of the first rotating arm 15 is rotatably connected to the top ends of two second rotating arms 16. An area scan camera 17 is rotatably mounted between the bottom ends of the two second rotating arms 16. A first motor 28 is mounted on the fixed base 14. The output end of the first motor 28 is connected to the first rotating arm 15. A camera storage slot 31 for accommodating the area scan camera 17 is provided on the first rotating arm 15. A second motor 29 is mounted on the outer side of the top end of the second rotating arm 16. The output end of the second motor 29 is connected to the bottom end of the first rotating arm 15. A third motor 30 is installed at the bottom of the arm 16. The output of the third motor 30 is connected to the area array camera 17. The first rotating arm 15, the second rotating arm 16 and the area array camera 17 are driven by the first motor 28, the second motor 29 and the third motor 30 respectively, realizing the pitch, swing and rotation adjustment of the camera after it is deployed, ensuring that the best observation angle can be obtained for different weld positions and angles. The camera storage slot 31 set on the first rotating arm 15 allows the area array camera 17 to be completely stored in the non-working state, which greatly reduces the storage volume of the mechanism and avoids collision with the workpiece or environment.

[0023] Working principle: When identifying the weld seam, the first motor 18, installed at the center of the top side of the fixed disk 8, starts, driving the turntable 19 connected to its output end to rotate. The rotational motion of the turntable 19, guided by the arc groove 20 on the guide rod 21, is converted into the synchronous radial linear motion of all the first sliders 12 along their respective linear rails 11, pushing them outward. At this time, the electromagnet 26 installed in the first slider 12 is energized, generating magnetic force, attracting the permanent magnet 27 installed in the second slider 13. The second slider 13 is magnetically locked to the first slider 12, moving outward together with the first slider 12 until the second slider 13 is located on the rotating ring 9. The first motor 28 drives the first rotating arm 15 to rotate downward to a vertical position, the second motor 29 drives the second rotating arm 16 to rotate downward, and the third motor 30 drives the area array camera 17 to rotate to the working posture aligned with the workpiece. Multiple area array cameras 17 form a stable multi-angle observation ring around the laser welding head 3; the electromagnet 26 is de-energized, and the magnetic force is released. When the force disappears, the magnetic lock between the second slider 13 and the first slider 12 is released. The second motor 23, installed on the top side of the fixed plate 8, starts and drives the rotating teeth 24 at its output end to rotate. The rotating ring 9 is rotated through the meshing inner ring teeth 25. The rotation of the rotating ring 9 drives the second sliders 13 on all rotating rings 9 to rotate. The second sliders 13 stop rotating when they are close to the support arm 5. The entire vision arm assembly fixed on the second sliders 13 then performs synchronous circumferential movement. During the circumduction process, the area array camera 17 continuously captures images of the weld area below at a high frame rate, realizing continuous, multi-angle scanning of the weld in a spiral or circular manner. After the scanning and recognition are completed, the rotating ring 9 is reset, the electromagnet 26 is re-energized, and the second slider 13 is attracted. The joint motors drive the vision arm assembly to fold and store. Finally, the first motor 18 reverses and drives all sliders to slide inward along the straight rail 11 back to the initial position. The entire weld recognition mechanism 2 returns to the stored state, ready for welding or movement.

[0024] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A laser welding robot having a weld seam recognition function, characterized by, The system includes a weld seam recognition mechanism (2) installed at the end of a six-axis robotic arm (1), on which a laser welding head (3) is mounted; the weld seam recognition mechanism (2) includes a top plate (4) connected to the end of the six-axis robotic arm (1), and a number of support arms (5) are arranged at equal angles on the outer side of the top plate (4), with the bottom ends of the support arms (5) connected to the bottom plate (6), the bottom plate (6) connected to the top of the laser welding head (3), and the bottom side of the top plate (4) connected to the fixed plate (8) via a connecting arm (7), the outer side of the fixed plate (8) A rotating ring (9) is rotatably mounted. Several linear rails (11) are set at equal angles on the fixed disk (8) and the rotating ring (9). A first slider (12) and a second slider (13) are slidably mounted on the linear rails (11). A fixed seat (14) is mounted on the outside of the second slider (13). The fixed seat (14) is rotatably connected to the top of the first rotating arm (15). The bottom of the first rotating arm (15) is rotatably connected to the top of two second rotating arms (16). A field array camera (17) is rotatably mounted between the bottoms of the two second rotating arms (16).

2. The laser welding robot having a weld seam recognition function according to claim 1, characterized in that, The outer end of the linear rail (11) of the rotating ring (9) is provided with a stop block. The first slider (12) slides on the linear rail (11) of the fixed disk (8), and the second slider (13) slides on the linear rail (11) of the fixed disk (8) and the rotating ring (9).

3. The laser welding robot having a weld seam recognition function according to claim 2, characterized in that, The fixed disk (8) has several straight grooves (10) at equal angles that are parallel to the straight rail (11). A turntable (19) is rotatably installed on the bottom side of the fixed disk (8), and several arc grooves (20) are opened at equal angles on the turntable (19). A guide rod (21) that passes through the straight grooves (10) and the arc grooves (20) is installed on the first slider (12).

4. The laser welding robot having a weld seam recognition function according to claim 3, characterized in that, A first motor (18) is installed at the top center of the fixed disk (8), and the output end of the first motor (18) is connected to the turntable (19).

5. The laser welding robot having a weld seam recognition function according to claim 4, characterized in that, The top side of the fixed disk (8) is equipped with a second motor (23), and the turntable (19) is provided with a gear groove (22). The output end of the second motor (23) is located in the gear groove (22) and a rotating tooth (24) is installed. The bottom side of the rotating ring (9) is provided with an inner ring tooth (25), and the inner ring tooth (25) meshes with the rotating tooth (24).

6. The laser welding robot having a weld seam recognition function according to claim 5, characterized in that, An electromagnet (26) is installed inside the first slider (12), and a permanent magnet (27) is installed inside the second slider (13). Several arc-shaped limiting rings (32) are arranged at equal angles on the outer side of the top of the fixed disk (8), and the arc-shaped limiting rings (32) are staggered with the first slider (12).

7. The laser welding robot having a weld seam recognition function according to claim 6, characterized in that, The fixed base (14) is equipped with a first motor (28), the output end of the first motor (28) is connected to the first rotating arm (15), and the first rotating arm (15) is provided with a camera storage slot (31) for accommodating the area array camera (17).

8. The laser welding robot having a weld seam recognition function according to claim 7, characterized in that, A second motor (29) is installed on the outer side of the top of the second rotating arm (16), and the output end of the second motor (29) is connected to the bottom end of the first rotating arm (15).

9. The laser welding robot having a weld seam recognition function according to claim 8, characterized by, The second rotating arm (16) is equipped with a third motor (30) at its bottom end, and the output end of the third motor (30) is connected to the area array camera (17).

10. The working method of a laser welding robot with weld seam recognition function according to claim 9, characterized in that, The specific operational steps of this working method are as follows: Step 1: When identifying the weld seam, the first motor (18) installed at the center of the top side of the fixed plate (8) is started, driving the turntable (19) connected to its output end to rotate. The rotational motion of the turntable (19) is converted into the radial linear motion of all the first sliders (12) along their respective linear rails (11) through the guiding effect of the arc groove (20) on the guide rod (21), pushing them outward. At this time, the electromagnet (26) installed in the first slider (12) is energized, generating magnetic force, attracting the permanent magnet (26) installed in the second slider (13). 7) The second slider (13) is magnetically locked to the first slider (12) and moves outward together with the first slider (12) until the second slider (13) is located on the rotating ring (9). The first motor (28) drives the first rotating arm (15) to rotate downward to the vertical position. The second motor (29) drives the second rotating arm (16) to rotate downward. The third motor (30) drives the area array camera (17) to rotate to the working posture aligned with the workpiece. Multiple area array cameras (17) form a stable multi-view observation ring around the laser welding head (3). Step 2: When the electromagnet (26) is de-energized and the magnetic force disappears, the magnetic lock between the second slider (13) and the first slider (12) is released. The second motor (23) installed on the top side of the fixed disk (8) starts and drives the rotating teeth (24) at its output end to rotate. The rotating ring (9) is rotated through the meshing inner ring teeth (25). The rotation of the rotating ring (9) drives the second slider (13) on all the rotating rings (9) to rotate. The second slider (13) stops when it rotates close to the support arm (5). The entire vision arm group fixed on the second slider (13) then performs synchronous circumferential movement. During the process of circumference, the area array camera (17) continuously takes pictures of the weld area below at a high frame rate, realizing continuous, multi-angle scanning of the weld in a spiral or circular manner. Step 3: After the scanning and recognition are completed, the rotating ring (9) is reset, the electromagnet (26) is re-energized, and the second slider (13) is attracted. The motors of each joint drive the vision arm group to fold and store. Finally, the first motor (18) reverses and drives all sliders to slide inward along the straight rail (11) back to the initial position. The entire weld recognition mechanism (2) returns to the storage state and is ready for welding or movement.

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