Portable dexterous robotic steel bridge deck panel weld tracking method and system

Abstract

The application discloses a portable intelligent robot steel bridge deck plate weld tracking method and system, comprising the following steps: building a welding database: the portable intelligent robot obtains the corresponding relationship among the weld appearance, welding parameters and welding gun posture of the steel bridge deck plate welding by adopting arc tracking and laser tracking, and establishes a database; weld identification and welding: the three-dimensional coordinates of the workpiece are obtained by a visual system before welding, the weld characteristic points are taken out, and welding is carried out based on the welding database. The application obtains the corresponding relationship among the weld appearance, welding parameters and welding gun posture based on arc tracking and laser tracking, and establishes a database; the three-dimensional coordinates of the workpiece are obtained by a visual system before welding, the weld characteristic points are taken out, and welding is carried out based on the welding database, so as to provide data support for obtaining a steel bridge deck plate with good forming and high fatigue performance. The method overcomes many shortcomings of the prior art, and expands the application range of the steel bridge deck plate welding.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of weld tracking method and system, in particular to a kind of portable dexterous robot steel bridge deck plate weld tracking method and system. BACKGROUND

[0002] Orthotropic steel bridge deck plate is the main unit commonly used in domestic bridge manufacturing industry, with its small quality density, large load bearing capacity, wide application scene and other characteristics, it has been widely used in Changjiang Bridge of Changtai and other large bridge buildings. With the rapid development of modernization, the use amount of automobile increases year by year, and part of the steel bridge deck plate appears fatigue problem during service. As the core component of bridge structure, the welding process of U rib and deck plate and the welding process of transverse diaphragm and deck plate play the most important role in the welding process of whole bridge, and are the key positions affecting the fatigue resistance of steel bridge deck plate.

[0003] The heat deformation generated in the process of steel bridge deck plate welding is continuously accumulated, which may deviate the weld position from the predetermined welding track, and the traditional teaching positioning method can only complete welding according to the predetermined welding route, cannot correct the position deviation occurred in the welding process, resulting in that the quality and precision of weld cannot meet the production requirements, and for a large number of welds, the efficiency of robot teaching welding is low. SUMMARY

[0004] The purpose of the present application is to provide a portable dexterous robot steel bridge deck plate weld tracking method and system, to improve the welding efficiency of flat angle welding of deck plate and transverse diaphragm and vertical angle welding of U rib and transverse diaphragm and the fatigue strength of steel bridge deck plate.

[0005] Technical scheme: the present application comprises the following steps:

[0006] S1, build welding database: portable robot obtains the corresponding relationship of weld appearance, welding parameters and welding gun posture of steel bridge deck plate welding by using arc tracking and laser tracking, and establishes database;

[0007] S2, weld identification and welding: obtain the three-dimensional coordinates of workpiece through visual system before welding, take out the weld feature points, and carry out welding based on welding database.

[0008] The arc tracking collects the flat angle welding data of deck plate and transverse diaphragm, and mainly ensures that there is no defect in the weld, the weld is smooth transition and the fatigue resistance of welded joint is good in the welding process.

[0009] The flat angle welding penetration prediction model of deck plate and transverse diaphragm obtained by arc tracking is: h=2.724*d1+1.777*d2-40.098, wherein h is the remaining height, d1 is the transverse diaphragm weld leg, and d2 is the deck plate weld leg or U rib weld leg.

[0010] The laser tracking collects the flat angle welding data of the panel and the diaphragm and the vertical angle welding data of the U rib and the diaphragm, and mainly ensures that there is no defect inside the welding seam, the welding seam is smoothly transitioned, and the welding joint is fatigue resistant during the welding process.

[0011] The vertical angle welding penetration prediction model of the U rib and the diaphragm obtained by the laser tracking is h = -21.074 * d1 - 5.752 * d2 + 295.829, wherein h is the reinforcement, d1 is the diaphragm welding leg, and d2 is the panel welding leg or the U rib welding leg.

[0012] The front end of the welding gun of the portable robot is equipped with a robot vision system.

[0013] The vision system comprises a camera, a lens, a light source, an image acquisition card and a vision processor.

[0014] The steel bridge panel is connected by the U rib, the panel and the diaphragm.

[0015] The steel bridge panel welding comprises the flat angle welding of the panel and the diaphragm and the vertical angle welding of the U rib and the diaphragm.

[0016] A portable dexterous robot steel bridge panel welding seam tracking system comprises:

[0017] A welding database building module: the portable dexterous robot obtains the corresponding relationship between the welding seam appearance and the welding parameters and the welding gun attitude by adopting arc tracking and laser tracking, and establishes a database.

[0018] A welding seam identification module: the three-dimensional coordinates of the workpiece are obtained by the vision system before welding, the welding seam feature points are taken out, and welding is carried out based on the welding database.

[0019] Beneficial effects: the steel bridge panel is welded by adopting arc tracking and laser tracking, the corresponding relationship between the welding seam appearance and the welding parameters and the welding gun attitude is obtained based on arc tracking and laser tracking, and a database is established; the three-dimensional coordinates of the workpiece are obtained by the vision system before welding, the welding seam feature points are taken out, and welding is carried out based on the welding database, which provides data support for obtaining a steel bridge panel with good forming and high fatigue performance, the method overcomes many shortcomings of the prior art, and expands the application range of the steel bridge panel welding. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a schematic view of typical sizes of the steel bridge panel welding joint. DETAILED DESCRIPTION

[0021] The application will be further described below with reference to the drawings.

[0022] The portable dexterous robot steel bridge deck plate weld tracking method of the present application is based on arc tracking and laser tracking weld forming regulation technology, and weld tracking technology with a vision system. The correspondence between the weld appearance and the welding parameters and the welding gun attitude is obtained based on the arc tracking and laser tracking two modes, and a database is established; the three-dimensional coordinates of the workpiece are obtained through the vision system before welding, the weld feature points are taken out, and welding is carried out based on the welding database. It specifically includes the following steps:

[0023] S1, build a welding database: the portable dexterous robot obtains the correspondence between the weld appearance and the welding parameters and the welding gun attitude of the steel bridge deck plate welding by using arc tracking and laser tracking two modes, and establishes a database.

[0024] The portable dexterous robot is a six-axis robot with a weight of less than 25 kg and can be directly moved. The portable dexterous robot realizes the welding of the steel bridge deck plate by using arc tracking and laser tracking two modes respectively, and obtains the correspondence between the weld appearance and the welding parameters and the welding gun attitude based on the arc tracking and laser tracking two modes, and establishes a database.

[0025] The arc tracking flat weld is a convex weld with a shape that is relatively close, the U rib weld leg and the panel weld leg have small differences, the weld area is large, and the forming is good. The vertical weld has a large weld depth, and the weld shape is irregular. In the two side weld toe parts, the base material cannot be fully melted, so the welding wire cannot be effectively filled, and the forming is poor. The positioning accuracy of arc tracking in the flat corner welding part is high, the error of the vertical corner welding part is large, and the overwelding deviation occurs. Arc tracking should be avoided as much as possible in vertical corner welding.

[0026] The flat corner weld has clear and regular lines, a smooth surface, and a metallic luster. The width and thickness of the weld are basically consistent, and there are no obvious defects. The transition at the corner is relatively smooth, and there are no large weld tumors, so fatigue cracks are not easy to occur.

[0027] Arc tracking mainly collects flat corner welding data of the panel and the transverse plate, while laser tracking collects flat corner welding data of the panel and the transverse plate and vertical corner welding data of the U rib and the transverse plate; during the welding process, the main purpose is to ensure that there are no defects inside the weld, the weld is smoothly transitioned, and the welded joint has good fatigue resistance. In the steel bridge deck plate welding process, the weld tracking technology can ensure that the welding process is stable, and the welding gun position is controlled at the set 2mm of the welding wire aligning the weld root.

[0028] The front end of the welding gun of the portable dexterous robot is equipped with a robot vision system, and the vision system includes a camera, a lens, a light source, an image acquisition card, and a vision processor.

[0029] The steel bridge deck plate is connected by U ribs, deck plates and cross partitions; the steel bridge deck plate welding mainly includes flat angle welding of the deck plate and the cross partition, and vertical angle welding of the U rib and the cross partition. Figure 1

[0030] S2, weld recognition and welding: before welding, the three-dimensional coordinates of the workpiece are obtained through the vision system, the weld feature points are taken out, and welding is carried out based on the welding database.

[0031] The application also provides a portable dexterous robot steel bridge deck plate weld tracking system, comprising:

[0032] The welding database building module: the portable dexterous robot obtains the corresponding relationship between the weld appearance and the welding parameters and the welding gun posture of the steel bridge deck plate welding by using arc tracking and laser tracking, and establishes a database.

[0033] The portable dexterous robot is a six-axis robot with a weight of less than 25 kg and can be directly moved, and the portable dexterous robot realizes the welding of the steel bridge deck plate by using arc tracking and laser tracking, respectively, and establishes a database based on the corresponding relationship between the weld appearance and the welding parameters and the welding gun posture obtained by using arc tracking and laser tracking.

[0034] Arc tracking mainly collects the flat angle welding data of the deck plate and the cross partition, while laser tracking collects the flat angle welding data of the deck plate and the cross partition and the vertical angle welding data of the U rib and the cross partition; during the welding process, the main purpose is to ensure that there is no defect inside the weld, the weld is smoothly transitioned, and the welded joint has good fatigue resistance. In the welding process of the steel bridge deck plate, the weld tracking technology can ensure that the welding process is stable, and the position of the welding gun is controlled at the set position of 2mm of the welding wire aligned with the root of the weld.

[0035] The front end of the welding gun of the portable dexterous robot is equipped with a robot vision system, and the vision system comprises a camera, a lens, a light source, an image acquisition card and a vision processor.

[0036] ​The steel bridge deck panel is connected by U ribs, deck panels and cross partitions; the steel bridge deck panel welding mainly includes flat angle welding of the deck panel and the cross partition, and vertical angle welding of the U rib and the cross partition. A flat angle welding penetration prediction model of the deck panel and the cross partition is obtained based on arc tracking: h=2.724*d1+1.777*d2-40.098; a vertical angle welding penetration prediction model of the U rib and the cross partition is obtained based on laser tracking: h=-21.074*d1-5.752*d2+295.829; wherein h is the reinforcement, d1 is the cross partition welding leg, and d2 is the deck panel welding leg or the U rib welding leg.

[0037] The weld recognition module: before welding, the three-dimensional coordinates of the workpiece are obtained through the vision system, the weld characteristic points are taken out, and welding is carried out based on the welding database.

[0038] Due to the size error of the steel bridge deck panel itself and the deformation caused by welding thermal stress, there is a difference between the actual weld track and the programmed track, and the large weld size deviation causes low fatigue performance and other problems, the present application builds a database of the influence of welding parameters and welding gun posture on weld formation, and realizes weld tracking based on the vision system, so as to provide data support for obtaining good steel bridge deck panel and high fatigue performance, which overcomes many shortcomings of the prior art and expands the application range of steel bridge deck panel welding.

[0039] Embodiment

[0040] The portable dexterous robot steel bridge deck panel weld tracking method of the embodiment comprises the following steps:

[0041] First, Q370qE for railway bridges is selected as the test material, and the deck panel, the U rib and the cross partition are all made of the same material. The U rib thickness is 8 mm, the deck panel thickness is 20 mm, and the cross partition thickness is 18 mm. The NBC-series inverter welding machine is selected, 1.6 mm diameter solid welding wire is used as the filler material, and CO2 is used as the protective gas.

[0042] The welding current of the vertical welding part at the connection between the cross partition and the U rib is 150-160 A, the welding voltage is 16±1 V, the wire feeding speed is 5 m / min, the welding speed is 11.9 cm / min, the welding wire oscillation frequency is 50 Hz, and the dry elongation is set to 15 mm; the welding parameters of the flat welding part and the vertical welding part at the connection between the cross partition and the deck panel are different, the welding current is selected to be 230-240 A, the welding voltage is 23±1 V, the wire feeding speed is 10.5 m / min, the welding speed is 26.0 cm / min, and the dry elongation is set to 25 mm; the welding from the flat angle welding to the vertical angle welding part needs to be continuously carried out, and the welding parameter adjustment in the middle of the way cannot be interrupted.

[0043] The arc tracking flat weld seam is convex weld seam, the shape is relatively close, the U rib weld leg and the panel weld leg have small difference, the weld seam area is large, and the forming is good. The vertical weld seam has large penetration, and the weld seam shape is irregular. In the two side weld toe parts, the base material cannot be fully melted, which leads to that the welding wire cannot be effectively filled, and the forming is poor. The arc tracking has high positioning accuracy in the flat corner welding part, the error in the vertical corner welding part is large, and the overwelding deviation occurs. The arc tracking should be avoided as far as possible in the vertical corner welding.

[0044] The flat corner weld seam has clear and regular texture, the surface is flat, has metal luster, the width and thickness of the weld seam are basically consistent, and have no obvious defects. The transition at the corner is relatively smooth, and has no large weld bead, and is not easy to have fatigue cracks.

[0045] Based on the arc tracking and the laser tracking, the corresponding relationship between the weld seam shape and the welding parameters is obtained, such as Figure 1 As shown in Table 1, based on the arc tracking, the flat corner weld penetration prediction model of the panel and the transverse plate is h = 2.724 * d1 + 1.777 * d2 - 40.098, and the vertical corner weld penetration prediction model of the U rib and the transverse plate obtained by laser tracking is h = -21.074 * d1 - 5.752 * d2 + 295.829. The welding gun front end is carried by the robot vision system. Before welding, the three-dimensional coordinates of the workpiece are obtained through the vision system, the weld seam feature points are taken out, the welding is carried out based on the arc tracking and the laser tracking weld penetration prediction model, and finally the weld seam with smooth weld seam and few defects is obtained.

[0046] Table 1 Typical size of steel bridge panel welding flat corner and vertical corner welding joint

[0047]

Claims

1. A portable, dexterous robot method for tracking weld seams in steel bridge decks, characterized in that, Includes the following steps: S1. Establishing a Welding Database: A six-axis portable robot weighing less than 25kg, capable of direct movement, was used to obtain the correspondence between weld morphology, welding parameters, and welding torch posture in steel bridge deck welding using both arc tracking and laser tracking methods, and a database was established. Arc tracking collected data on the fillet welds between the deck and the diaphragm. The predicted penetration depth model for the fillet welds between the deck and the diaphragm obtained by arc tracking is: h = 2.724*d1 + 1.777*d2 - 40.098, where h is the reinforcement height, d1 is the weld leg of the diaphragm, and d2 is the weld leg of the deck or the weld leg of the U-rib. Laser tracking collected data on the fillet welds between the deck and the diaphragm, as well as the vertical fillet welds between the U-rib and the diaphragm. The predicted penetration depth model for the vertical fillet welds between the U-rib and the diaphragm obtained by laser tracking is: h = -21.074*d1 - 5.752* d2+295.829; where h is the excess height, d1 is the weld leg of the transverse diaphragm, and d2 is the weld leg of the panel or the weld leg of the U-rib. S2. Weld seam recognition and welding: The welding gun of the portable robot is equipped with a robot vision system. The robot vision system includes a camera, lens, light source, image acquisition card, and vision processor. Before welding, the vision system obtains the three-dimensional coordinates of the steel bridge panel, which is composed of U-ribs, panels and cross diaphragms. Weld seam feature points are extracted. Based on the welding database, the panel and cross diaphragm are welded with flat fillet welds, and the U-ribs and cross diaphragms are welded with vertical fillet welds.

2. A tracking system for the portable dexterous robot steel bridge deck weld tracking method according to claim 1, characterized in that, include: Welding Database Construction Module: A six-axis portable robot weighing less than 25kg, capable of direct movement, uses both arc tracking and laser tracking to obtain the correspondence between weld morphology, welding parameters, and welding torch posture in steel bridge deck welding, and establishes a database. Arc tracking collects fillet weld data between the deck and diaphragm. The predicted penetration depth model for fillet welds between the deck and diaphragm obtained by arc tracking is: h = 2.724*d1 + 1.777*d2 - 40.098, where h is the reinforcement height, d1 is the diaphragm weld leg, and d2 is the deck weld leg or U-rib weld leg. Laser tracking collects fillet weld data between the deck and diaphragm, as well as vertical fillet weld data between the U-rib and diaphragm. The predicted penetration depth model for vertical fillet welds between the U-rib and diaphragm obtained by laser tracking is: h = -21.074*d1 - 5.752* d2+295.829; where h is the excess height, d1 is the weld leg of the transverse diaphragm, and d2 is the weld leg of the panel or the weld leg of the U-rib. Weld seam recognition module: The welding gun of the portable robot is equipped with a robot vision system. The robot vision system includes a camera, lens, light source, image acquisition card, and vision processor. Before welding, the vision system obtains the three-dimensional coordinates of the steel bridge panel, which is composed of U-ribs, panels and cross diaphragms. Weld seam feature points are extracted, and the panel and cross diaphragm are welded with fillet welds and the U-ribs and cross diaphragms are welded with fillet welds based on the welding database.

Images