A welding system and weld seam tracking method based on an 11-axis robot

Abstract

This invention discloses a welding system based on an 11-axis robot, including a guide rail laid on a processing platform, an industrial robot slidingly engaged with the guide rail, and a welding end effector mounted on the industrial robot. The welding end effector includes an end-mounted base, a welding mechanism and a sensor bracket mounted on the end-mounted base. The welding mechanism includes a welding head, a guide rail assembly for linear movement of the welding head, a rotating assembly for circular movement of the welding head, and a transmission control system. The sensor bracket is equipped with a line laser sensor for measuring bevel morphology and welding trajectory deviation, and the measurement results from the line laser sensor are sent to the transmission control system to generate corresponding action commands to control the trajectory compensation movement path of the welding mechanism. This invention also provides a weld seam tracking method. The system provided by this invention can realize weld seam welding tasks under multiple angle postures and real-time weld seam tracking.

Description

Technical Field

[0001] This invention belongs to the technical field of large ship processing, and particularly relates to a welding system and weld seam tracking method based on an 11-axis robot. Background Technology

[0002] Welding is a crucial material forming method in important fields such as aerospace, shipbuilding, and bridge construction, and its quality significantly impacts the final product quality and lifespan. Currently, welding operations are mostly performed manually or using welding motion control systems developed by robot manufacturers, utilizing the robot's own welding program. For the former, manual welding heavily relies on the operator's welding experience and working conditions, making it difficult to effectively guarantee welding quality. Furthermore, the noise and arc light generated during the welding process are detrimental to worker health. For the latter, both the welding trajectory and the welding arc movement are performed by the robot. Existing welding end effectors typically only serve to hold the welding torch; the weld measurement device on it moves with the welding arc movement, causing instability in the measurement device's field of view, increasing the difficulty of processing measurement results, and affecting measurement accuracy. In addition, relying on the robot's own welding program is not conducive to real-time correction of weld deviations and real-time weld tracking.

[0003] Patent document CN117226376A discloses an automatic welding robot, including a base, a welding robotic arm mounted on one top end of the base, and symmetrically arranged movable seats on both sides of the top of the base. A disc is rotatably connected to the inner end of each movable seat, and a positioning component is mounted on the disc. A housing is positioned between the two positioning components and is fixedly mounted on the top of the base. A first cylinder is fixedly mounted on the housing, and a weld seam processing component is positioned above the first cylinder. This device allows the workpiece to be positioned on the housing between a pair of turntables; however, the device's design significantly limits the maximum size of the weld seam that can be processed.

[0004] Patent document CN117245303A discloses a welding robot and its welding method adapted to large steel components, including a control terminal, a magnetic crawling mobile seat (1) and a robotic arm (2); the robotic arm (2) is equipped with a ring welding mechanism, which includes a mounting plate (3) fixedly connected to the end of the robotic arm (2), a rotating ring (4) rotatably connected to the upper part of the mounting plate (3), and a welding torch (5) and a camera (6) are mounted on the rotating ring (4); both the mounting plate (3) and the rotating ring (4) are notched ring structures, the rotating ring (4) extends into the mounting plate (3) and is fixedly connected to a gear ring (7), the gear ring (7) meshes with a set of symmetrically arranged drive gears (8), the drive gears (8) are connected to a first motor (9) fixed on the mounting plate (3), and the welding torch (5) is connected to the rotating ring (4) through a first lead screw assembly (10); The control terminal includes a control module. The input end of the control module is connected to the monitoring module. The camera (6) is connected to the input end of the monitoring module. The output end of the control module is connected to the welding execution module and the positioning execution module. The magnetic crawling moving seat (1), the robotic arm (2), and the first lead screw assembly (10) are all connected to the output end of the positioning execution module. The welding torch (5) and the first motor (9) are both connected to the output end of the welding execution module. This device rotates the workpiece to be welded through a rotating ring, while the camera and welding head are stationary relative to the rotating ring. Although this avoids the problem of positioning deviation caused by the mutual movement of the welding head and the workpiece, the welding head under this method can only complete the task of welding seams of specific sizes and shapes. Summary of the Invention

[0005] The purpose of this invention is to provide a welding system and weld seam tracking method based on an 11-axis robot. This system can realize weld seam welding tasks under multiple angle postures and real-time weld seam tracking.

[0006] To achieve the first objective of the present invention, a welding system based on an 11-axis robot is provided, including a guide rail laid on a processing platform, an industrial robot that slides with the guide rail, and the industrial robot being equipped with a welding end effector; The welding end effector includes an end mounting base, a welding mechanism and a sensor bracket mounted on the end mounting base. The welding mechanism includes a welding head, a guide rail assembly that drives the welding head to move linearly, a rotating assembly that drives the welding head to move in an arc, and a transmission control system. The sensor bracket is equipped with a line laser sensor for measuring the bevel shape and welding trajectory deviation. Based on the measurement results of the line laser sensor, the signal is sent to the transmission control system to generate corresponding action commands to control the trajectory compensation motion path of the welding mechanism.

[0007] This invention decouples the welding path motion from the welding arc motion. Specifically, it utilizes the coordination between the linear motion of the guide rail pair and the pendulum motion of the rotating shaft in the welding end effector to complete different arc motions of the welding head. At the same time, a line laser sensor is introduced to measure the deviation of the weld position to correct the welding trajectory, thereby completing a high-quality weld task.

[0008] Specifically, the industrial robot includes a sliding base that slides with the guide rail and a robotic arm mounted on the sliding base.

[0009] Specifically, the motion path of the welding mechanism includes Z-shaped swing arc motion, V-shaped swing arc motion, and triangular swing arc motion.

[0010] Specifically, the line laser sensor is also equipped with an arc spatter baffle to prevent welding sparks from damaging the equipment.

[0011] Specifically, the guide rail assembly includes a first guide rail pair and a second guide rail pair arranged in an alternating manner. The first guide rail pair includes a first guide rail disposed on the end mounting base and a first sliding plate that is slidably engaged. The second guide rail pair includes a second guide rail that is alternating with the first guide rail and disposed on the first sliding plate, and a second sliding plate that is slidably engaged. The second sliding plate is provided with a welding torch holder for fixing the welding head.

[0012] Specifically, the rotating assembly includes a first rotating shaft and a second rotating shaft with their axes perpendicular to each other. The first rotating shaft is fixed to the second slide plate, and the second rotating shaft is disposed at the rotating end of the first rotating shaft, and the rotating end of the second rotating shaft is connected to the welding torch bracket.

[0013] Specifically, the welding head includes a straight welding torch head and a bent welding torch head.

[0014] To achieve the second objective of this invention, a weld seam tracking method is provided, implemented using the aforementioned 11-axis robot-based welding system, comprising the following steps: Step 1: Use an industrial robot to move the welding end effector to the welding position; Step 2: When the laser light plane of the line laser sensor is located at the weld point Pi to be welded, use the line laser sensor to measure and save the weld deviation of point Pi along the direction of the first guide rail pair and the second guide rail pair. According to the preset direction of motion, when the welding head moves to the point Pi to be welded, the welding trajectory deviation is compensated by the first guide rail pair and the second guide rail pair. The compensation value is equal to the above-mentioned saved deviation, and the compensation direction is determined by the positive or negative sign of the measured deviation. Step 3: According to the welding point number of the point to be welded in the welding task, repeat the above steps 1 to 2 until the weld seam tracking welding is completed.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. By decoupling the welding path motion from the welding arc motion, and coordinating the linear motion of the guide rail pair and the pendulum motion of the rotating axis in the 4-axis welding end effector, various arc motions of the welding torch, welding trajectory correction motions, and adjustments to the welding torch push-pull angle can be completed. This improves the adjustability of welding motion parameters, provides high motion flexibility, and can adapt to various welding processes. 2. The welding end effector can ensure that its line laser sensor does not move with the swing arc movement and welding trajectory correction movement, which reduces the field of view adjustment work of the line laser sensor and reduces the burden and difficulty of weld image processing. 3. Welding tasks are completed by the robot executing offline programs and combining weld seam tracking, eliminating the need for manual teaching or online path planning by the robot, thus improving welding efficiency and quality. Attached Figure Description

[0016] Figure 1 This is a system structure diagram of the 11-axis robot welding system provided in this embodiment; Figure 2 This is a schematic diagram of the welding end effector provided in this embodiment; Figure 3 This is a schematic diagram of weld seam tracking for the weld seam tracking method provided in this embodiment; In the diagram, 1. Guide rail; 2. Industrial robot; 3. Welding end effector; 4. End mounting base; 5. First guide rail pair; 6. Second guide rail pair; 7. Zero position bracket; 8. Sensor bracket; 9. Line laser sensor; 10. Arc spatter baffle; 11. First rotating axis; 12. Transmission control system; 13. Second rotating axis; 14. Welding torch bracket; 15. Welding head. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0018] like Figure 1As shown, this embodiment provides an 11-axis robot welding system. The system includes a guide rail 1 arranged on a processing platform and an industrial robot 2 that moves on the guide rail 1. The industrial robot 2 includes a sliding base that slides with the guide rail 1 and a robotic arm arranged on the sliding base. The end of the robotic arm is provided with a welding end effector 3.

[0019] The robotic arm is driven by the sliding base to reach the position of the workpiece to be processed, and the welding end effector 3 is moved to the welding position by the robotic arm.

[0020] like Figure 2 As shown, the welding end effector 3 provided in this embodiment includes an end mounting base 4 fixed to the end of the robotic arm. A welding mechanism and a sensor bracket 8 are provided on the end mounting base 4. The welding mechanism includes a first guide rail pair 5 and a second guide rail pair 6 arranged in an alternating manner. A welding gun bracket 14 and a welding head 15 are provided on the second guide rail pair 6. A first rotating shaft 11 and a second rotating shaft 13 are provided between the welding gun bracket 14 and the second guide rail pair 6.

[0021] The first guide rail assembly 5 includes a first guide rail disposed on the end mounting base 4 and a first sliding plate that is slidably engaged. The first guide rail is vertically arranged on the end mounting base 4, so that the first sliding plate can move vertically relative to the end mounting base 4. The second guide rail assembly 6 includes a second guide rail that is intersected with the first guide rail and disposed on the first sliding plate, and a second sliding plate that is slidably engaged. The second guide rail is vertically arranged on the first sliding plate, so that the second sliding plate can move vertically relative to the first sliding plate.

[0022] The fixed end of the first rotating shaft 11 is mounted on the second slide plate, and the axis of the first rotating shaft 11 is arranged perpendicular to the second slide plate and parallel to the end mounting base 4. At the same time, the rotating end of the first rotating shaft 11 drives the fixed end of the second rotating shaft 13 to rotate, and the rotation of the second rotating shaft 13 drives the welding gun bracket 14 to rotate, so that the welding head 15 swings at multiple angles. The axes of the first rotating shaft 11 and the second rotating shaft 13 are arranged perpendicular to each other.

[0023] In addition, the first guide rail pair 5, the second guide rail pair 6, the first rotating shaft 11, and the second rotating shaft 13 are all equipped with a zero-position bracket 7 for quick reset.

[0024] The four motion components are controlled by the transmission control system 12 to achieve the following motion: 1) The periodic movement of the first rotating shaft 11 or the second guide rail pair 6 of the welding end effector 3 can realize the welding Z-shaped swing arc motion; 2) The welding V-shaped swing motion can be realized by the periodic linkage between the first guide rail pair 5 and the first rotating shaft 11 of the welding end effector 3; 3) The welding triangular swing motion can be realized by the periodic linkage between the first guide rail pair 5 and the first rotating shaft 11 of the welding end effector 3; 4) The welding push-pull angle can be adjusted by adjusting the second rotating shaft 13 of the welding end actuator 3.

[0025] Furthermore, the offset distance between the line laser sensor bracket 8 of the welding end effector 3 and the welding torch bracket 14, as well as the relative positional relationship between the first guide rail pair 5, the second guide rail pair 6, the first rotating shaft 11, and the second rotating shaft 13, ensure that when the first guide rail pair 5, the second guide rail pair 6, the first rotating shaft 11, and the second rotating shaft 13 are in the zero position, the axis of the welding head 15 end is parallel to the laser light plane of the line laser sensor 9 and intersects with the axis of the first rotating shaft 11. This allows the line laser sensor 9 to directly measure the real-time deviation of the welding trajectory along the direction of the first guide rail pair 5 and the second guide rail pair 6.

[0026] This embodiment also provides a weld seam tracking method, implemented using the 11-axis robot-based welding system provided in the above embodiment, including the following steps: 1) The industrial robot 2 with an external axis runs an offline program, driving the welding end effector 3 to move in the welding direction; 2) At this time, the laser plane of the line laser sensor 9 is located at the weld point Pi. The line laser sensor 9 combines the deviation of the industrial control computer measurement point Pi along the direction of the first guide rail pair 5 and the second guide rail pair 6 and saves it. 3) such as Figure 3 As shown, when the welding head 15 moves to Pi, the first guide rail pair 5 and the second guide rail pair 6 move simultaneously along their respective directions to compensate. The compensation displacement is equal to the measurement deviation of Pi along their respective directions. The compensation direction is determined by the positive or negative sign of the measurement deviation, thereby completing the correction of the welding trajectory deviation at Pi and realizing weld tracking at Pi. 4) i = 1, 2, 3...n, repeat steps 2) to 3), and finally achieve welding head 15 along the weld seam.

[0027] In summary, the system provided by this invention decouples the welding path motion from the welding arc motion. Through the coordination between the linear motion of the guide rail pair in the welding end effector and the pendulum motion of the rotating shaft, various arc motions of the welding torch, welding trajectory correction motions, and adjustments to the welding torch push-pull angle can be completed, improving the adjustability of welding motion parameters, providing high motion flexibility, and adapting to various welding processes. 2) At the same time, the welding end effector structure allows the line laser sensor to directly measure the deviation of the welding trajectory along the first guide rail pair and the second guide rail pair without conversion, reducing the weld deviation measurement process. 3) This system directly compensates for welding trajectory deviations by using the first and second guide rail pairs in the welding end effector, eliminating the need to transmit the welding trajectory deviations to the robot and have the robot perform the compensation, thus simplifying the weld tracking process. 4) By decoupling the motion of this system, the welding end effector can ensure that its line laser sensor does not move with the swing arc motion and the welding trajectory correction motion, which reduces the field of view adjustment work of the line laser sensor and reduces the burden and difficulty of weld image processing. 5) Welding tasks are completed by the robot executing offline programs and combining weld seam tracking, eliminating the need for manual teaching or online path planning by the robot, thus improving welding efficiency and quality.

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0029] Furthermore, the terms "upper," "lower," "inner," "outer," "front," and "rear" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Unless otherwise specifically stated, the relative steps, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0030] Of course, the above description is only a specific embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes or modifications made to the structure, features and principles described in the claims of the present invention should be included in the scope of the claims of the present invention.

[0031] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A welding system based on an 11-axis robot, characterized in that, Includes a guide rail laid on a processing platform, an industrial robot that slides with the guide rail, and the industrial robot is equipped with a welding end effector; The welding end effector includes an end mounting base, a welding mechanism and a sensor bracket mounted on the end mounting base. The welding mechanism includes a welding head, a guide rail assembly that drives the welding head to move linearly, a rotating assembly that drives the welding head to move in an arc, and a transmission control system. The guide rail assembly includes a first guide rail pair and a second guide rail pair arranged in an alternating manner. The first guide rail pair includes a first guide rail disposed on the end mounting base and a first sliding plate that is slidably engaged. The second guide rail pair includes a second guide rail that is alternating with the first guide rail and disposed on the first sliding plate, and a second sliding plate that is slidably engaged. The second sliding plate is provided with a welding gun bracket for fixing the welding head. The rotating assembly includes a first rotating shaft and a second rotating shaft with their axes perpendicular to each other. The first rotating shaft is fixed to the second slide plate, and the second rotating shaft is disposed at the rotating end of the first rotating shaft and connected to the welding gun bracket. The sensor bracket is equipped with a line laser sensor for measuring the bevel shape and welding trajectory deviation. Based on the measurement results of the line laser sensor, the signal is sent to the transmission control system to generate corresponding action commands to control the trajectory compensation motion path of the welding mechanism. When the first guide rail pair, the second guide rail pair, the first rotating shaft, and the second rotating shaft are in the zero position, the axis of the welding head end is parallel to the laser light plane of the line laser sensor and intersects with the axis of the first rotating shaft. The welding head includes a straight welding torch head and a bent welding torch head; The workflow of the welding system includes the following steps: Step 1: Use an industrial robot to move the welding end effector to the welding position; Step 2: When the laser light plane of the line laser sensor is located at the weld point Pi to be welded, use the line laser sensor to measure and save the weld deviation of point Pi along the direction of the first guide rail pair and the second guide rail pair. According to the preset direction of motion, when the welding head moves to the point Pi to be welded, the welding trajectory deviation is compensated by the first guide rail pair and the second guide rail pair. The compensation value is equal to the above-mentioned saved deviation, and the compensation direction is determined by the positive or negative sign of the deviation. Step 3: Based on the welding point number of the point to be welded in the welding task, repeat steps 1 to 2 above until the weld seam tracking welding is completed.

2. The welding system based on an 11-axis robot according to claim 1, characterized in that, The industrial robot includes a sliding base that slides with the guide rail and a robotic arm mounted on the sliding base.

3. The welding system based on an 11-axis robot according to claim 1, characterized in that, Both the guide rail assembly and the rotating assembly are equipped with a zero-position bracket for resetting.

4. The welding system based on an 11-axis robot according to claim 1, characterized in that, The oscillating motion path of the welding mechanism includes zigzag oscillating motion, v-shaped oscillating motion, and triangular oscillating motion.

5. The welding system based on an 11-axis robot according to claim 1, characterized in that, The line laser sensor is also equipped with an arc spatter baffle.

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