Door handle laser automatic welding system and method for rail transit

Abstract

The invention relates to the technical field of industrial automatic welding, in particular to a door handle laser automatic welding system and method for rail transit. The device comprises a rack, a tool table, a mechanical arm I, a mechanical arm II and a material placing frame, wherein the tool table, the mechanical arm I, the mechanical arm II and the material placing frame are arranged on the rack; a workpiece picker is arranged at the tail end of the mechanical arm I; the workpiece picker comprises a rotating cylinder, a clamping jaw and a position sensor; a tracking welding mechanism is arranged at the tail end of the mechanical arm II; the tracking welding mechanism comprises a fixing support, a laser tracker and a laser welder. The laser welder comprises a laser welding gun head and a wire feeding mechanism. The welding quality is excellent and stable, the surplus height of a welding seam can be accurately controlled to be 0.5-1 mm, penetration is good, the appearance is attractive, and subsequent grinding is greatly reduced or even eliminated; the automation degree is extremely high, full-process automation is achieved, manual repair welding is needed only when extreme abnormity occurs, the production efficiency is greatly improved, door handles of different models can be rapidly adapted, and multi-variety and small-batch production is met.

Description

Technical Field

[0001] This invention relates to the field of industrial automated welding technology, specifically to a laser automated welding system and method for door handles in rail transit. Background Technology

[0002] In rail transit equipment manufacturing, door handles are frequently used, and their welding quality directly impacts the product's safety, durability, and appearance. Traditional manual welding of door handles presents several problems: First, the quality is inconsistent, affected by the operator's skill and condition, resulting in varying weld height and penetration, easily leading to defects such as incomplete fusion and undercut. Second, it is inefficient, with slow manual welding and numerous post-weld grinding processes, increasing costs and time. Third, consistency is poor; in areas with non-standard curved inner edges or uneven gaps at the tail (sometimes exceeding 2mm), it is difficult for manual operators to accurately control the welding torch trajectory, making shaping difficult. Fourth, it is labor-intensive, with repetitive high-intensity work detrimental to worker health and posing safety risks. To address these issues, the industry has attempted to introduce robotic welding, as exemplified by the patent with publication number CN118578024A. However, general solutions suffer from poor welding results when dealing with complex door handle structures, irregular welds, and workpieces with manufacturing tolerances, due to a lack of real-time sensing and correction capabilities, requiring manual re-welding in critical areas. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an automated laser welding system and method for door handles in rail transit, which solves the problems of unstable welding quality, low efficiency, excessively high requirements for workpiece consistency, and inability to effectively handle complex / irregular welds in the prior art.

[0004] The technical solution adopted in this invention is as follows: An automated laser welding system for door handles in rail transit includes a frame, a tooling table, robotic arm I, robotic arm II, and a material loading frame mounted on the frame, wherein: A tooling table is set on one side of robotic arm I, and a fixed tooling is set on it, with the door handle workpiece to be welded placed inside the fixed tooling; Robotic arm I, with a workpiece picker at its end, is used to pick up the pre-fixed door handle workpiece from the tooling table and transfer it to the welding area; wherein: The workpiece picker includes a rotary cylinder, grippers, and a position sensor. The front end of the rotary cylinder is equipped with grippers, which have positioning grooves and are positioned towards the door handle workpiece. The position sensor is located at the rear end of the rotary cylinder and is used to detect whether the door handle workpiece has been picked up in place. Robotic arm II, with a tracking welding mechanism at its end effector, is used to track and weld door handle workpieces transferred to the welding area; wherein: The tracking welding mechanism includes a fixed bracket connected to the robotic arm II, and a laser tracker and a laser welder mounted on the fixed bracket. The laser tracker is arranged parallel to the laser welder and is used to perform three-dimensional scanning and positioning of the welding area of ​​the door handle workpiece. The laser welder includes a laser welding torch head and a wire feeding mechanism. A gas protection nozzle is installed at the end of the laser welding torch head and is used to provide protective gas toward the welding area. The wire feeding mechanism is inclined from below the laser welding torch head and is used to feed the welding wire. The material storage box, located on one side of robotic arm I, is used to store the finished door handle workpieces after welding.

[0005] This technical solution automates the entire process of handling door handles for rail transit from gripping and welding to storage by constructing a welding system including a frame, tooling table, and robotic arm. This improves welding quality and production efficiency while reducing reliance on manual labor. Specifically, the workpiece picker of robotic arm I precisely picks up the pre-fixed door handle workpiece and moves it to the welding area. Then, the tracking welding mechanism of robotic arm II uses a laser tracker to perform a three-dimensional scan of the welding area to obtain accurate position information. Based on this information, the laser welder, in conjunction with the wire feeding mechanism and gas protection nozzle, completes high-quality welding. This technical solution can precisely control the weld reinforcement, resulting in good penetration, a beautiful appearance, reduced subsequent grinding processes, and improved product quality. It automates the entire process of loading, welding, and unloading, requiring manual re-welding only in extreme anomalies, significantly improving production efficiency. It can handle workpiece consistency deviations, solve the problem of large-gap welds, and quickly adapt to different welding models by changing tooling and programs, making it suitable for multi-variety, small-batch production.

[0006] In addition, the laser automated welding system for door handles in rail transit proposed above according to the present invention may also have the following additional technical features: According to one embodiment of the present invention, a track is provided on the frame, and a sliding base frame is connected to robotic arm I and robotic arm II on the track for adjusting the position of robotic arm I and robotic arm II in the horizontal direction to adapt to the welding requirements of door handle workpieces of different sizes and specifications. A locking device is provided between the sliding base frame and the track for locking and fixing after adjustment.

[0007] In this technical solution, the track on the frame provides a guide path for the horizontal movement of the sliding base. The sliding base is connected to robotic arms I and II. By sliding on the track, the relative horizontal positions of robotic arms I and II can be changed. The locking device utilizes a mechanical locking mechanism. After the sliding base moves to the appropriate position, the interaction between locking components, such as wedge insertion and bolt tightening, fixes the sliding base to the track, ensuring the stability of robotic arms I and II during operation to accommodate the welding of door handle workpieces of different sizes. If necessary, the sliding base is driven by an electric system.

[0008] According to one embodiment of the present invention, both robotic arm I and robotic arm II are six-axis robots. The six-axis robots integrate a servo control system and a vision inspection system. The laser tracker on robotic arm II is a high-resolution laser sensor with a resolution of 0.08 mm, a field of view of 100 mm × 130 mm, and a frequency of 1000 Hz, used to acquire the actual spatial coordinates and morphological data of the weld seam of the door handle workpiece. The laser welder is a 1500W fiber laser welder.

[0009] In this technical solution, the six-axis robot has six rotation axes, enabling it to achieve complex and flexible motion postures in space and accurately reach designated positions and angles. The servo control system ensures the precise and stable movement of each axis of the six-axis robot by controlling parameters such as the speed and torque of the servo motors, achieving high-precision positioning and trajectory tracking. The high-resolution laser sensor on the robotic arm II emits laser light and receives reflected light, acquiring the actual spatial coordinates and shape data of the weld seam based on principles such as time of flight or phase difference. The vision inspection system processes and identifies the features of the target object, providing welding guidance for the laser welder. The 1500W fiber laser welder achieves efficient welding with a high-energy laser beam.

[0010] According to one embodiment of the present invention, the door handle workpiece includes an inner non-standard arc-shaped area and a tail gap uneven area; the fixing fixture is provided with a groove that mates with the door handle workpiece, and the door handle workpiece is placed in the groove and pressed and tack-fixed.

[0011] This technical solution is beneficial for improving machining accuracy, as the groove precisely adapts to the special areas of the workpiece, and the clamping point prevents displacement, ensuring accurate machining dimensions; it is beneficial for improving machining efficiency, as the workpiece is positioned quickly and accurately, reducing adjustment time and accelerating the machining process; it is beneficial for enhancing product quality stability, as the stable positioning makes the machining quality more consistent and reduces the defect rate.

[0012] According to one embodiment of the present invention, the protective gas provided by the gas protection nozzle is a mixture of argon and carbon dioxide, and the mixing ratio is adjusted according to different welding materials and process requirements; the gas protection nozzle is provided with a flow regulating valve and a pressure sensor, the flow regulating valve is used to regulate the flow rate of the protective gas, and the pressure sensor is used to monitor the pressure of the protective gas in real time.

[0013] According to one embodiment of the present invention, the laser tracker is connected to the vision inspection system of a six-axis robot. The vision inspection system includes an information processing module, which analyzes and processes the information acquired by the laser tracker to determine whether there are defects in the weld, including incomplete fusion and undercut, and feeds the inspection results back to the servo control system. The vision inspection system has pre-set welding programs for different models of door handles, making it suitable for multi-variety, small-batch production.

[0014] This technical solution connects a laser tracker to a vision inspection system, uses an information processing module to analyze and judge weld defects and provide feedback on the results, and pre-sets multiple welding programs to achieve real-time monitoring of welding quality and multi-variety, small-batch production, thereby completing welding tasks more efficiently and accurately.

[0015] To achieve the above objectives, the present invention also provides an automated laser welding method for door handles in rail transit.

[0016] An automated laser welding method for door handles in rail transit includes the following steps: S1. Collaborative Operation: The workpiece picker equipped with robotic arm I picks up the pre-fixed door handle workpiece from the fixed fixture and transfers it to the welding work area; the tracking welding mechanism integrated with robotic arm II tracks and welds the door handle workpiece transferred to the welding area. S2. Weld seam location: The weld seam area of ​​the door handle workpiece is located by high-precision three-dimensional scanning using a laser tracker. The weld seam area includes the non-standard arc area on the inside and the uneven gap area at the tail. The actual spatial coordinates and shape data of the weld seam are obtained and compared with the theoretical trajectory preset by the vision inspection system. S3. Welding Path: The servo control system dynamically corrects the welding path and posture of the robotic arm II based on real-time data fed back by the vision inspection system; in the non-standard arc area on the inner side, the welding posture and the running speed of the robotic arm are optimized to ensure stable weld formation; in the uneven gap area at the tail, the laser power, wire filling speed and the running speed of the robotic arm II are automatically adjusted to compensate for gap changes and achieve effective penetration. S4. Welding and unloading: After welding is completed, robotic arm I moves again to remove the finished workpiece from the welding area and place it in the material placement box on one side. S5. Circular Production: The system resets and waits for the next door handle workpiece to achieve continuous automated production.

[0017] This technical solution utilizes the collaborative operation of robotic arms I and II to achieve the gripping, transfer, and tracking welding of door handle workpieces, thus constructing an automated welding system. A laser tracker performs high-precision 3D scanning and positioning of special weld areas on the door handle workpiece, particularly the non-standard arc-shaped inner area and the uneven gap at the tail, acquiring actual data and comparing it with a preset theoretical trajectory to provide data support for welding. The servo control system dynamically corrects the welding path and posture of robotic arm II based on real-time data feedback from the vision inspection system, optimizing parameters such as welding posture, running speed, laser power, and wire feed speed for different areas to ensure stable weld formation and effective penetration. Finally, robotic arm I completes the welding unloading, and the system resets to achieve cyclical production, reaching the goal of continuous automated welding production and comprehensively improving welding efficiency and quality.

[0018] According to an embodiment of the present invention, the welding method further includes the following preliminary steps: S0. Pre-treatment of workpiece: Clean the door handle workpiece before welding to ensure that the weld seam and the areas on both sides are free of oil, rust and burrs; place the door handle workpiece in the groove of the fixing fixture and press and fix it.

[0019] This technical solution first involves cleaning the door handle workpiece before welding to remove impurities such as oil, rust, and burrs from the weld seam and both sides, preventing defects such as porosity and slag inclusions during welding and ensuring the purity and strength of the weld seam. Then, the door handle workpiece is precisely placed in the groove of the fixing fixture, and the initial positioning is achieved by utilizing the fit between the groove and the workpiece. Subsequently, clamping and tack fixing operations are performed to keep the workpiece in a stable position and posture during welding, preventing problems such as weld seam displacement and poor forming caused by workpiece movement.

[0020] According to an embodiment of the present invention, the welding method further includes the following post-step: S6. Abnormal Handling: If the visual inspection system determines that a weld cannot be effectively welded due to excessive deviation, it will be marked at the corresponding workstation and handed over to a human for local repair welding.

[0021] In this technical solution, during the laser automated welding process, although various methods are used to ensure welding accuracy in the early stages, some welds may still deviate too much due to various factors, affecting the effectiveness of the welding. At this time, the vision inspection system makes a real-time judgment on the weld quality. Once it is found that a weld deviation exceeds the allowable range and cannot be effectively welded, the system will quickly mark it clearly at the corresponding workstation to identify the problem location. Then, the workpiece is handed over to a human for local repair welding. By utilizing the flexibility and precision of human operation, the problematic weld is repaired in a targeted manner, thereby making up for the shortcomings of automated welding and ensuring that the quality of the final welded product meets the standards.

[0022] Compared with the prior art, the present invention has the following advantages: (1) Excellent and stable welding quality, which can accurately control the weld reinforcement height to 0.5-1mm, with good penetration and beautiful appearance, greatly reducing or even eliminating the need for subsequent grinding; (2) The degree of automation is extremely high, realizing full-process automation. Only in extreme abnormalities is manual welding required, which greatly improves production efficiency; (3) With excellent adaptability and flexibility, the laser weld seam tracking system can cope with workpiece consistency deviations and solve the problem of large gap welds. Moreover, by changing tooling and programs, it can quickly adapt to different models of door handles to meet the needs of multi-variety, small-batch production. Attached Figure Description

[0023] Figure 1This is a flowchart illustrating the principle of the method of the present invention.

[0024] Figure 2 This is the assembly drawing of the workbench of the system of the present invention.

[0025] Figure 3 This is a schematic diagram of the workpiece pickup mechanism.

[0026] Figure 4 This is a schematic diagram of a laser tracker.

[0027] Figure 5 This is a schematic diagram of a laser welder.

[0028] Figure 6 This is a motion logic block diagram of the method of the present invention.

[0029] In the diagram: 1. Frame; 2. Tooling table; 3. Robotic arm I; 4. Workpiece picker; 41. Rotary cylinder; 42. Gripper; 43. Position sensor; 44. Door handle workpiece; 5. Robotic arm II; 6. Tracking welding mechanism; 61. Fixed bracket; 62. Laser tracker; 63. Laser welding torch head; 64. Gas protection nozzle; 65. Wire feeding mechanism; 7. Material placement frame. Detailed Implementation

[0030] 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, not all, of the embodiments of the present invention. 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.

[0031] Example 1 like Figures 1 to 6 As shown, this embodiment provides an automated laser welding system for door handles in rail transit, including a frame 1, a tooling table 2, a robotic arm I 3, a robotic arm II 5, and a material placement frame 7 mounted on the frame 1, wherein: like Figure 2 As shown, the tooling table 2 is set on one side of the robotic arm I3, and a fixed tooling is set on it. The door handle workpiece 44 to be welded is placed in the fixed tooling. like Figure 3 As shown, the robotic arm I3 has a workpiece picker 4 at its end, used to pick up the pre-fixed door handle workpiece 44 from the tooling table 2 and transfer it to the welding area; wherein: The workpiece picker 4 includes a rotary cylinder 41, a gripper 42, and a position sensor 43. The front end of the rotary cylinder 41 is provided with the gripper 42, which has a positioning groove and is positioned towards the door handle workpiece 44. The position sensor 43 is located at the rear end of the rotary cylinder 41 and is used to detect whether the door handle workpiece 44 has been picked up in place. like Figure 4 and Figure 5 As shown, robotic arm II 5 has a tracking welding mechanism 6 at its end, used to track and weld the door handle workpiece 44 that has been moved to the welding area; wherein: The tracking welding mechanism 6 includes a fixed bracket 61 connected to the robotic arm II 5, and a laser tracker 62 and a laser welder mounted on the fixed bracket 61. The laser tracker 62 is arranged parallel to the laser welder and is used to perform three-dimensional scanning and positioning of the welding area of ​​the door handle workpiece 44. The laser welder includes a laser welding gun head 63 and a wire feeding mechanism 65. A gas protection nozzle 64 is installed at the end of the laser welding gun head 63 and is used to provide protective gas toward the welding area. The wire feeding mechanism 65 is inclined below the laser welding gun head 63 and is used to feed the welding wire. The material placement frame 7 is located on one side of the robotic arm I3 and is used to store the finished door handle workpiece 44 after welding.

[0032] like Figures 1 to 6 As shown, this technical solution automates the entire process of picking up, welding, and storing rail transit door handle workpieces by constructing a welding system including a frame 1, a tooling table 2, and a robotic arm. This improves welding quality and production efficiency while reducing reliance on manual labor. Specifically, the workpiece picker 4 of robotic arm I 3 precisely picks up the pre-fixed door handle workpiece 44 and moves it to the welding area. Then, the tracking welding mechanism 6 of robotic arm II 5 uses a laser tracker 62 to perform a three-dimensional scan of the welding area to obtain accurate position information. Based on this information, the laser welder, in conjunction with the wire feeding mechanism 65 and the gas protection nozzle 64, completes high-quality welding. This technical solution can precisely control the weld reinforcement, resulting in good penetration, a beautiful appearance, reduced subsequent grinding processes, and improved product quality. It automates the entire process of loading, welding, and unloading, requiring manual re-welding only in extreme abnormalities, significantly improving production efficiency. It can handle workpiece consistency deviations, solve the problem of large-gap welds, and quickly adapt to different welding models by changing tooling and programs, making it suitable for multi-variety, small-batch production.

[0033] In addition, the laser automated welding system for door handles in rail transit proposed above according to the present invention may also have the following additional technical features: According to one embodiment of the present invention, a track is provided on the frame 1, and a sliding base frame is connected to the robotic arm I3 and robotic arm II5 on the track for adjusting the position of robotic arm I3 and robotic arm II5 in the horizontal direction to adapt to the welding requirements of door handle workpieces 44 of different sizes and specifications. A locking device is provided between the sliding base frame and the track for locking and fixing after adjustment.

[0034] In this technical solution, the track on the frame 1 provides a guide path for the horizontal movement of the sliding base. The sliding base is connected to robotic arms I3 and II5. By sliding on the track, the relative horizontal positions of robotic arms I3 and II5 can be changed. The locking device utilizes a mechanical locking mechanism. After the sliding base moves to the appropriate position, the interaction between locking components, such as wedge insertion and bolt tightening, fixes the sliding base to the track, ensuring the stability of robotic arms I3 and II5 during operation to accommodate the welding of door handle workpieces 44 of different sizes. If necessary, the sliding base is driven by an electric system.

[0035] According to one embodiment of the present invention, both robotic arms I3 and II5 are six-axis robots. The six-axis robots integrate a servo control system and a vision inspection system. The laser tracker 62 on robotic arm II5 is a high-resolution laser sensor with a resolution of 0.08mm, a field of view of 100mm×130mm, and a frequency of 1000Hz. It is used to acquire the actual spatial coordinates and shape data of the weld seam of the door handle workpiece 44. The laser welder is a 1500W fiber laser welder.

[0036] In this technical solution, the six-axis robot has six rotation axes, enabling it to achieve complex and flexible motion postures in space and accurately reach designated positions and angles. The servo control system ensures the precise and stable movement of each axis of the six-axis robot by controlling parameters such as the speed and torque of the servo motors, achieving high-precision positioning and trajectory tracking. The high-resolution laser sensor on the robotic arm II5 emits laser light and receives reflected light, acquiring the actual spatial coordinates and shape data of the weld seam based on principles such as time of flight or phase difference. The vision inspection system processes and identifies the features of the target object, providing welding guidance for the laser welder. The 1500W fiber laser welder achieves efficient welding with a high-energy laser beam.

[0037] According to one embodiment of the present invention, the door handle workpiece 44 includes an inner non-standard arc-shaped area and a tail gap uneven area; the fixing fixture is provided with a groove that mates with the door handle workpiece 44, and the door handle workpiece 44 is placed in the groove and pressed and tack-fixed.

[0038] This technical solution is beneficial for improving machining accuracy, as the groove precisely adapts to the special areas of the workpiece, and the clamping point prevents displacement, ensuring accurate machining dimensions; it is beneficial for improving machining efficiency, as the workpiece is positioned quickly and accurately, reducing adjustment time and accelerating the machining process; it is beneficial for enhancing product quality stability, as the stable positioning makes the machining quality more consistent and reduces the defect rate.

[0039] According to one embodiment of the present invention, the protective gas provided by the gas protection nozzle 64 is a mixture of argon and carbon dioxide, and the mixing ratio is adjusted according to different welding materials and process requirements; the gas protection nozzle 64 is provided with a flow regulating valve and a pressure sensor, the flow regulating valve is used to regulate the flow rate of the protective gas, and the pressure sensor is used to monitor the pressure of the protective gas in real time.

[0040] According to one embodiment of the present invention, the laser tracker 62 is connected to the vision inspection system of a six-axis robot. The vision inspection system includes an information processing module, which analyzes and processes the information acquired by the laser tracker 62 to determine whether there are defects in the weld, including incomplete fusion and undercut, and feeds the inspection results back to the servo control system. The vision inspection system has pre-set welding programs for different models of door handles, making it suitable for multi-variety, small-batch production.

[0041] This technical solution connects the laser tracker 62 to the vision inspection system, uses the information processing module to analyze and judge weld defects and provide feedback on the results, and pre-sets multiple welding programs to achieve real-time monitoring of welding quality and multi-variety, small-batch production, thereby completing welding tasks more efficiently and accurately.

[0042] Example 2 Based on Example 1, such as Figures 1 to 6 As shown, this embodiment provides an automated laser welding method for door handles in rail transit, including the following steps: S1. Collaborative operation: The workpiece picker 4 equipped with robotic arm I3 picks up the door handle workpiece 44 that has been fixed on the fixture and moves it to the welding work area; the tracking welding mechanism 6 integrated with robotic arm II5 tracks and welds the door handle workpiece 44 that has been moved to the welding area. S2. Weld seam location: The weld seam area of ​​the door handle workpiece 44 is located by high-precision three-dimensional scanning using the laser tracker 62. The weld seam area includes the inner non-standard arc area and the uneven gap area at the tail. The actual spatial coordinates and shape data of the weld seam are obtained and compared with the theoretical trajectory preset by the vision inspection system. S3. Welding Path: The servo control system dynamically corrects the welding path and posture of the robotic arm II5 based on real-time data fed back by the vision inspection system; in the non-standard arc area on the inner side, the welding posture and the running speed of the robotic arm are optimized to ensure stable weld formation; in the uneven gap area at the tail, the laser power, wire filling speed and the running speed of the robotic arm II5 are automatically adjusted to compensate for gap changes and achieve effective penetration. S4. Welding and unloading: After welding is completed, the robotic arm I3 moves again to remove the finished workpiece from the welding area and place it into the material placement box 7 on one side. S5. Cyclic Production: The system resets and waits for the next door handle workpiece 44 to achieve continuous automated production.

[0043] This technical solution utilizes the collaborative operation of robotic arms I3 and II5 to achieve the gripping, transfer, and tracking welding of the door handle workpiece 44, thus constructing an automated welding system. A laser tracker 62 performs high-precision three-dimensional scanning and positioning of the special weld seam areas of the door handle workpiece 44, particularly the non-standard arc-shaped inner area and the uneven gap at the tail, acquiring actual data and comparing it with the preset theoretical trajectory to provide data support for welding. The servo control system dynamically corrects the welding path and posture of robotic arm II5 based on real-time data feedback from the vision detection system, optimizing parameters such as welding posture, running speed, laser power, and wire feed speed for different areas to ensure stable weld formation and effective penetration. Finally, robotic arm I3 completes the welding unloading, and the system resets to achieve cyclical production, reaching the goal of continuous automated welding production and comprehensively improving welding efficiency and quality.

[0044] According to an embodiment of the present invention, the welding method further includes the following preliminary steps: S0. Pre-treatment of workpiece: Clean the door handle workpiece 44 to be welded before welding to ensure that the weld and the areas on both sides are free of oil, rust and burrs; place the door handle workpiece 44 in the groove of the fixing fixture and press and fix it.

[0045] This technical solution first involves cleaning the door handle workpiece 44 before welding to remove impurities such as oil, rust, and burrs from the weld seam and both sides, thus preventing defects such as porosity and slag inclusions during welding and ensuring the purity and strength of the weld seam. Then, the door handle workpiece 44 is precisely placed in the groove of the fixing fixture, and the initial positioning is achieved by utilizing the compatibility between the groove and the workpiece. Subsequently, clamping and tack fixing operations are performed to keep the workpiece in a stable position and posture during welding, preventing problems such as weld seam displacement and poor forming caused by workpiece movement.

[0046] According to an embodiment of the present invention, the welding method further includes the following post-step: S6. Abnormal Handling: If the visual inspection system determines that a weld cannot be effectively welded due to excessive deviation, it will be marked at the corresponding workstation and handed over to a human for local repair welding.

[0047] In this technical solution, during the laser automated welding process, although various methods are used to ensure welding accuracy in the early stages, some welds may still deviate too much due to various factors, affecting the effectiveness of the welding. At this time, the vision inspection system makes a real-time judgment on the weld quality. Once it is found that a weld deviation exceeds the allowable range and cannot be effectively welded, the system will quickly mark it clearly at the corresponding workstation to identify the problem location. Then, the workpiece is handed over to a human for local repair welding. By utilizing the flexibility and precision of human operation, the problematic weld is repaired in a targeted manner, thereby making up for the shortcomings of automated welding and ensuring that the quality of the final welded product meets the standards.

[0048] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the invention should also be covered within the protection scope of the invention. Therefore, the protection scope of the invention should be determined by the scope of the claims.

Claims

1. A door handle laser automated welding system for rail transportation, characterized in that, The utility model provides a kind of door handle welding device, including rack (1), and tooling table (2), mechanical arm I (3), mechanical arm II (5) and material frame (7) being arranged on rack (1), wherein: Tooling table (2) is arranged on the side of mechanical arm I (3), and fixed tooling is arranged on it, and the door handle workpiece (44) to be welded is placed in fixed tooling; Mechanical arm I (3) is arranged with workpiece pickup (4) at its end, for grabbing the door handle workpiece (44) that has been fixed from tooling table (2) and moving it to welding area;Wherein: Workpiece pickup (4) includes rotary cylinder (41), clamping jaw (42) and position sensor (43), rotary cylinder (41) is provided with clamping jaw (42) at its front end, clamping jaw (42) has positioning groove and is arranged towards door handle workpiece (44);Position sensor (43) is located at the rear end of rotary cylinder (41), for detecting whether door handle workpiece (44) is grabbed in place; Mechanical arm II (5) is arranged with tracking welding mechanism (6) at its end, for tracking and welding the door handle workpiece (44) moved to welding area;Wherein: Tracking welding mechanism (6) includes fixed support (61) connected with mechanical arm II (5), and laser tracker (62) and laser welder arranged on fixed support (61);Laser tracker (62) is arranged in parallel with laser welder, and laser tracker (62) is used for three-dimensional scanning and positioning of the welding area of door handle workpiece (44);Laser welder includes laser welding gun head (63) and wire feeding mechanism (65), and gas protection nozzle (64) is installed at the end of laser welding gun head (63), and gas protection nozzle (64) is used for providing protective gas towards welding area;Wire feeding mechanism (65) is arranged obliquely below laser welding gun head (63), for conveying welding wire; Material frame (7) is arranged on the side of mechanical arm I (3), for storing finished product door handle workpiece (44) after welding.

2. The door handle laser automated welding system for rail transportation as claimed in claim 1, wherein, Track is arranged on the rack (1), and the track is connected with the mechanical arm I (3) and the mechanical arm II (5) through the sliding chassis, for adjusting the positions of the mechanical arm I (3) and the mechanical arm II (5) in the horizontal direction to adapt to the welding requirements of door handle workpieces (44) of different sizes, and a locking device is arranged between the sliding chassis and the track, which is locked and fixed after being adjusted in place.

3. The door handle laser automated welding system for rail transportation as claimed in claim 1, wherein, The mechanical arm I (3) and the mechanical arm II (5) are both six-axis robots, which integrate servo control system and visual detection system, wherein: the laser tracker (62) on the mechanical arm II (5) is a high-resolution laser sensor, which has 0.08mm resolution, 100mm×130mm field of view and 1000Hz frequency, for obtaining the actual spatial coordinates and appearance data of the weld of the door handle workpiece (44);The laser welder is a 1500W fiber laser welder.

4. The door handle laser automated welding system for rail transportation as claimed in claim 1, wherein, The door handle workpiece (44) includes an inner non-standard arc region and a tail gap uneven region;The fixed tooling is provided with a groove matched with the door handle workpiece (44), and the door handle workpiece (44) is placed in the groove and is pressed and fixed.

5. The door handle laser automated welding system for rail transportation as claimed in claim 1 wherein, The shielding gas provided by the gas shielding nozzle (64) is a mixture of argon and carbon dioxide, and the mixing ratio is adjusted according to different welding materials and process requirements; a flow regulating valve and a pressure sensor are arranged on the gas shielding nozzle (64), the flow regulating valve is used to adjust the flow of the shielding gas, and the pressure sensor is used to monitor the pressure of the shielding gas in real time.

6. The door handle laser automated welding system for rail transportation as claimed in claim 3 wherein, The laser tracker (62) is connected with a visual detection system of the six-axis robot, and the visual detection system includes an information processing module. The information processing module analyzes and processes information acquired by the laser tracker (62), judges whether a weld is defective, including incomplete fusion and undercut, and feeds back the detection result to the servo control system.

7. The door handle laser automated welding system for rail transportation as claimed in claim 6 wherein, The visual detection system presets welding programs of different models of door handle workpieces, and is suitable for multi-variety and small-batch production modes.

8. A method for laser automated welding of a door handle for rail transportation, using the laser automated welding system for a door handle for rail transportation according to any one of claims 1 to 7, characterized in that The method comprises the following steps: S1, cooperative operation: a workpiece pickup device (4) provided by the mechanical arm I (3) grabs the fixed door handle workpiece (44) from the fixed tooling, and moves the door handle workpiece (44) to the welding work area; a tracking and welding mechanism (6) integrated with the mechanical arm II (5) tracks and welds the door handle workpiece (44) moved to the welding area; S2, weld location finding: the laser tracker (62) performs high-precision three-dimensional scanning and location finding on the weld area of the door handle workpiece (44), the weld area includes an inner non-standard arc area and a tail gap uneven area, actual space coordinates and appearance data of the weld are acquired, and the actual space coordinates and appearance data are compared with a preset theoretical track of the visual detection system; S3, welding path: the servo control system dynamically corrects the welding path and posture of the mechanical arm II (5) according to real-time data fed back by the visual detection system; for the inner non-standard arc area, the welding posture and the running speed of the mechanical arm are optimized to ensure stable formation of the weld; for the tail gap uneven area, the laser power, the wire feeding speed and the running speed of the mechanical arm II (5) are automatically adjusted to compensate for the gap change and realize effective penetration; S4, welding blanking: after welding, the mechanical arm I (3) moves again to take out the finished workpiece from the welding area and place the finished workpiece into the material placing frame (7) on one side; S5, cyclic production: the system is reset, and the next door handle workpiece (44) is waited, so that continuous automatic production is realized.

9. The method for laser automated welding of door handles for rail transportation according to claim 8, characterized in that, The welding method further comprises the following pre-step: S0, workpiece pretreatment: the door handle workpiece (44) to be welded is cleaned before welding to ensure that the weld and the two side areas are free of oil stains, rust and burrs; the door handle workpiece (44) is placed in the groove of the fixed tooling and is pressed and fixed.

10. The method for laser automated welding of door handles for rail transportation according to claim 8, characterized in that, The welding method further comprises the following post-step: S6, abnormality processing: if the visual detection system determines that a weld at a certain position cannot be effectively welded due to excessive deviation, the corresponding position is marked, and manual local repair welding is performed.

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