A system and method for identifying and locating a sub-penetration weld

Abstract

The application provides a small group of welding seam identification positioning system, including a roller, a gantry and a general control system, the gantry can move along the roller, the roller can transport the workpiece to be welded, the laser emitted by the laser emitter on the gantry can be irradiated on the bottom plate and the rib plate of the workpiece to be welded, the visual system on the gantry can continuously detect the workpiece to be welded, the general control system can identify the approximate position of the welding seam according to the comparison result of the image information and the three-dimensional model, the general control system can control the movement of the laser emitter, and the end position of the welding seam can be accurately positioned according to the image information of the laser deformation, so that the technical problem that the starting end of the welding seam cannot be accurately identified and positioned in the prior art is solved. The application also discloses a use method of the above-mentioned group of welding seam identification positioning system, and two sets of coordinate systems with different origins are established, so that the requirements of high-precision calculation of the visual system and high-efficiency operation of the general control system are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ship manufacturing, in particular to a small assembly welding seam identification and positioning system and method. BACKGROUND

[0002] Small assembly is a basic component structure in the modern ship assembly construction mode, which has the characteristics of large demand and relatively simple structure. The small assembly production process mainly includes the assembly, welding, repair and polishing of the bottom plate and the rib plate.

[0003] In the prior art, small assembly welding is usually performed manually, by welding trolley or by a small number of welding robots. Manual welding and welding trolley have unstable quality and low work efficiency. The welding robot has a large amount of calculation and low efficiency when identifying the welding seam, and cannot accurately identify and position the starting end of the welding seam. SUMMARY

[0004] In view of the defects in the prior art, the present application provides a small assembly welding seam identification and positioning system to solve the technical problems of large amount of calculation, low efficiency and inability to accurately identify and position the starting end of the welding seam when identifying the welding seam in the prior art.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a small assembly welding seam identification and positioning system, comprising a roller, a gantry and a general control system. The gantry can move horizontally along the tracks on both sides of the roller. The roller can transport a workpiece to be welded. A laser emitter is arranged on the gantry. The laser emitted by the laser emitter can shine on the bottom plate and the rib plate of the workpiece to be welded. The laser is linear on the bottom plate without welding seam, and is broken line on the bottom plate with welding seam. A vision system is arranged on the gantry. The vision system can continuously detect the workpiece to be welded to obtain multiple image information. The general control system comprises a trajectory planning system and a database system. The database system stores a three-dimensional model of the workpiece to be welded. The general control system can identify the approximate position of the welding seam according to the comparison result of the image information and the three-dimensional model. The trajectory planning system can plan the motion trajectory of the laser emitter according to the approximate position of the welding seam. The general control system can control the motion of the laser emitter according to the motion trajectory, and locate the end or tail position of the welding seam according to the image information of the laser deformation.

[0006] In an embodiment, the vision system comprises a camera fixed on the top of the gantry, and the focal length and lens direction of the camera are fixed.

[0007] In an embodiment, two mechanical arms are symmetrically arranged on the gantry, and two laser emitters are arranged on the mechanical arms respectively. The general control system can control the motion of the two mechanical arms respectively.

[0008] In an embodiment, the end of the mechanical arm is provided with a welding gun.

[0009] In an embodiment, the general control system controls the movement of the two mechanical arms on the two sides of the web plate respectively.

[0010] The application also provides a method for identifying and positioning a small group of welds, which adopts the identification and positioning system of a small group of welds and comprises the following steps:

[0011] S1. The visual system performs first visual sensing detection on the workpiece to be welded, acquires first image information of the workpiece to be welded, and identifies the outer contour and part number of the workpiece to be welded;

[0012] S2. The first image information is sent to the database in the general control system, the database calls the three-dimensional model of the workpiece to be welded, and the general control system identifies the approximate position of the weld according to the comparison result of the first image information and the three-dimensional model;

[0013] S3. The trajectory planning system plans the movement trajectory of the laser according to the approximate position of the weld, so that the range of laser movement can cover the approximate position of the weld, and the general control system controls the movement of the laser emitter according to the trajectory planned by the trajectory planning system, while the visual system performs continuous visual sensing detection on the workpiece to be welded;

[0014] S4. When the visual system detects that the laser emitted by the laser emitter on the bottom plate of the workpiece to be welded is deformed, the end or tail position of the weld can be located.

[0015] In an embodiment, in step S3, the movement trajectory starts from the middle section of the approximate position of the weld and moves towards the end or tail of the approximate position of the weld, and the movement trajectory covers the end or tail of the approximate position of the weld.

[0016] In an embodiment, in step S3, the general control system first controls the movement of the laser emitter on the left side of the web plate according to the trajectory planned by the trajectory planning system, and then controls the movement of the laser emitter on the right side of the web plate.

[0017] In an embodiment, in step S4, the visual system respectively visually detects the position of the laser deformation of the welds on the left and right sides of the web plate to locate the end or tail position of the welds on the left and right sides of the web plate.

[0018] In an embodiment, before step S1, there is also step S0: establishing a first coordinate system and a second coordinate system, a first origin of the first coordinate system is arranged at an end point of the gantry bottom, a direction in which the workpiece to be welded is conveyed is a positive direction of an X1 axis, a direction in which the end point points to the roller is a positive direction of a Y1 axis, and a vertically upward direction is a positive direction of a Z1 axis; a second origin of the second coordinate system is arranged at an end point on the same side of the first coordinate system origin at the roller plane entrance, positive directions of an X2 axis, a Y2 axis and a Z2 axis are the same as the positive directions of the X1 axis, the Y1 axis and the Z1 axis, and coordinates of the first coordinate system origin in the second coordinate system are (a, b, c);

[0019] In step S4, the coordinates of the weld end or tail position in the first coordinate system are (a1, b1, c1), and the total control system can convert the weld end position coordinates into coordinates (a+a1, b+b1, c+c1) in the second coordinate system.

[0020] The air layer drag reduction device protruding from the ship bottom and the installation method thereof have the following beneficial effects:

[0021] 1) The visual system and the laser emitter are arranged on the gantry in the small group assembly weld seam identification and positioning system, the laser emitted by the laser emitter can be irradiated on the bottom plate and the rib plate of the workpiece to be welded, the visual system can continuously perform visual sensing detection on the workpiece to be welded to obtain multiple image information, the total control system can identify the approximate position of the weld seam according to the comparison result of the image information and the three-dimensional model, the trajectory planning system can plan the movement trajectory of the laser emitter according to the approximate position of the weld seam, the total control system can control the movement of the laser emitter according to the movement trajectory, and accurately position the end position of the weld seam according to the image information of the laser deformation, thereby solving the technical problem that the starting end of the weld seam cannot be accurately identified and positioned in the prior art.

[0022] 2) In the identification and positioning method using the small group assembly weld seam, the first coordinate system is established at the end point of the gantry bottom, and the second coordinate system is established at the roller plane entrance, the coordinates of the visual system on the gantry in the first coordinate system are unchanged when the gantry moves, the visual system can position the coordinates of the weld seam end in the first coordinate system, the coordinates of the weld seam end in the second coordinate system can be obtained through coordinate transformation, the visual system and the total control system are developed respectively, the requirements of high-precision calculation of the visual system are met, and the operation efficiency of the total control system is improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0024] Figure 1 A schematic diagram of a first coordinate of a three-dimensional structure of a recognition positioning system of a small group assembly welding seam according to an embodiment of the present application is shown.

[0025] Figure 2 A schematic diagram of a workpiece to be welded according to an embodiment of the present application is shown.

[0026] Figure 3 A Figure 1 A local enlarged view at A in the middle;

[0027] Figure 4 A top view of a recognition positioning system of a small group assembly welding seam according to an embodiment of the present application and a first and second coordinate schematic diagram are shown.

[0028] Reference signs: 1, gantry; 2, camera; 3, common base; 4, first mechanical arm; 5, second mechanical arm; 6, first laser emitter; 7, second laser emitter; 8, rib plate; 9, bottom plate; 10, first welding seam; 11, second welding seam; 12, first welding torch; 13, second welding torch; 15, roller. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0031] With reference to the drawings, Figures 1-4 the embodiments of the present application disclose a recognition positioning system of a small group assembly welding seam, which comprises a roller 15, a gantry 1 and a general control system.

[0032] The gantry frame 1 can move horizontally along the tracks on both sides of the roller conveyor 15, which can transport the workpieces to be welded, as shown in the attached figure. Figure 1 As shown, the first robotic arm 4 and the second robotic arm 5 are symmetrically fixed to the gantry frame via a common base 3. A first laser emitter 6 and a second laser emitter 7 are respectively mounted on the first robotic arm 4 and the second robotic arm 5. The laser emitted by the laser emitters can illuminate the base plate 9 and the stiffening plate 8 of the workpiece to be welded, as shown in the attached diagram. Figure 3 As shown, the laser beam is linear on the unwelded base plate 1 and zigzag on the welded base plate 1. The first robotic arm 4 and the second robotic arm 5 are respectively equipped with a first welding torch 12 and a second welding torch 13 to locate the weld end position before welding the base plate 9 and the stiffening plate 8. The gantry frame 1 is equipped with a vision system that can continuously visually sense and detect the workpiece to be welded to obtain multiple image information. The vision system includes a camera fixed to the top 1 of the gantry frame, and the focal length and lens direction of the camera are fixed to ensure that the position of the camera's projection point remains unchanged in the captured image.

[0033] The overall control system includes a trajectory planning system and a database system. The database system stores a three-dimensional model of the workpiece to be welded. The overall control system can identify the approximate location of the weld seam based on the comparison between the image information and the three-dimensional model. The trajectory planning system can plan the motion trajectory of the laser emitter based on the approximate location of the weld seam.

[0034] In one implementation, the central control system controls the movement of the gantry 1 to drive the movement of the laser emitter by controlling the motion trajectory planned by the trajectory planning system, and locates the end position of the weld seam based on the image information of the laser deformation.

[0035] In one implementation, the central control system controls the movement of the first robotic arm 4 and the second robotic arm 5 according to the motion trajectory planned by the trajectory planning system, thereby driving the movement of the laser emitter, and locates the beginning and end positions of the weld seam according to the image information of the laser deformation.

[0036] like Figure 2As shown, the bottom plate 9 and the web plate 8 of the workpiece to be welded are respectively provided with a first weld 10 and a second weld 11. The trajectory planning system plans a movement trajectory of the laser emitted by the laser emitter according to the approximate position of the weld identified by the general control system, so that the laser emitted by the laser emitter moves from a position 5-10 cm away from the end head of the approximate position of the weld to the end head or the end tail of the approximate position of the weld, and stops after moving 10-15 cm, so as to ensure that the area scanned by the laser includes the end head or the end tail of the approximate position of the weld, and the laser hits the weld in a broken line shape, and changes into a straight line shape at the end head. The general control system positions the position where the laser photographed by the camera 2 changes from the broken line shape into the straight line shape as the end head or the end tail position of the weld. The general control system controls the movement of the laser emitters on the left and right sides of the web plate according to the movement trajectory planned by the movement trajectory planning system, and respectively locates the end head and end tail positions of the first weld 10 and the end head and end tail positions of the second weld 10.

[0037] The application also provides a method for identifying and positioning a small group of standing welds. The method comprises the following steps after the workpiece to be welded is transported to below the gantry 1 by the roller 15 using the above-mentioned system for identifying and positioning a small group of standing welds:

[0038] S1. The visual system performs first visual sensing detection on the workpiece to be welded, acquires first image information of the workpiece to be welded, and identifies the outer contour and the part number of the workpiece to be welded;

[0039] S2. The first image information is sent to the database in the general control system, the database calls the three-dimensional model of the workpiece to be welded, and the general control system identifies the approximate position of the weld according to the comparison result of the first image information and the three-dimensional model;

[0040] S3. The trajectory planning system plans a movement trajectory of the laser according to the approximate position of the weld, so that the laser moves in a range covering the approximate position of the weld. The general control system controls the movement of the laser emitter according to the trajectory planned by the trajectory planning system, and the visual system performs continuous visual sensing detection on the workpiece to be welded at the same time.

[0041] S4. When the visual system detects that the laser emitted by the laser emitter on the bottom plate of the workpiece to be welded is deformed, the end head position of the weld can be located.

[0042] In an embodiment, in step S3, the movement trajectory starts from the middle section of the approximate position of the weld, moves towards the end head or the end tail of the approximate position of the weld, and covers the end head or the end tail of the approximate position of the weld. In this way, the position of the end head or the end tail can be located more quickly.

[0043] In an embodiment, in step S3, the general control system first controls the movement of the laser emitter on the left side of the web plate according to the trajectory planned by the trajectory planning system, and then controls the movement of the laser emitter on the right side of the web plate. In this way, the lasers on the left and right sides of the web plate are prevented from interfering with each other when they scan at the same time.

[0044] In an embodiment, in step S4, the visual system visually detects the positions of the laser deformation of the left and right side welds of the web plate respectively to locate the head and tail positions of the left and right side welds of the web plate.

[0045] In an embodiment, before step S1, there is also step S0: establishing a first coordinate system and a second coordinate system, the first origin of the first coordinate system is arranged at the bottom end point of the gantry, the direction of the X1 axis is the positive direction of the first coordinate system, the direction of the Y1 axis is the positive direction of the gantry, and the vertical upward direction is the positive direction of the Z1 axis; the second origin of the second coordinate system is arranged at the end point on the same side of the first coordinate system origin at the entrance of the roller table plane, the positive directions of the X2 axis, Y2 axis and Z2 axis are the same as the positive directions of the X1 axis, Y1 axis and Z1 axis, and the coordinates of the first coordinate system origin in the second coordinate system are (a, b, c);

[0046] In step S4, the coordinates of the located weld head or tail position in the first coordinate system are (a1, b1, c1), and the total control system can convert the coordinates of the weld head position into the coordinates (a+a1, b+b1, c+c1) in the second coordinate system.

[0047] When the gantry moves, the coordinates of the visual system on the gantry in the first coordinate system remain unchanged, and the coordinates of the located weld head or tail position in the first coordinate system can be obtained by coordinate transformation. By establishing two sets of coordinate systems in the identification and positioning method of the small group fillet weld, the visual system and the total control system can be developed respectively, the visual system needs higher precision, and higher precision data format can be used in its own system and coordinate system, while other parts of the total control system do not need such high precision, so it is not necessary to maintain a very high precision data format for the visual subsystem. The high-precision data format has lower efficiency than the low-precision data format in operation. Then, by separating the two, the calculation amount of the total control system is reduced, and the running efficiency of the algorithm is improved.

[0048] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A system for identifying and positioning small vertical weld seams, comprising a roller conveyor, a gantry frame, and a central control system, wherein the gantry frame can move horizontally along tracks on both sides of the roller conveyor, and the roller conveyor can transport workpieces to be welded, characterized in that... The gantry is equipped with a laser emitter, which emits a laser beam that illuminates the base plate and stiffening plate of the workpiece to be welded. The laser beam is linear on the base plate without welds and zigzag on the base plate with welds. The gantry is also equipped with a vision system, which performs continuous visual sensing and detection on the workpiece to be welded to acquire multiple image information. The overall control system includes a trajectory planning system and a database system. The database system stores a three-dimensional model of the workpiece to be welded. The overall control system can identify the approximate location of the weld by comparing the image information with the three-dimensional model. The trajectory planning system can plan the motion trajectory of the laser emitter based on the approximate location of the weld. The overall control system can control the movement of the laser emitter based on the motion trajectory and locate the end position of the weld based on the image information of the laser deformation. The trajectory planning system, based on the approximate location of the weld identified by the overall control system, plans the laser emitted by the laser emitter to move from the approximate location of the weld towards the end or tail of the weld.

2. The identification and positioning system for small-group weld seams according to claim 1, characterized in that: The vision system includes a camera fixed to the top of the gantry, and the focal length and lens orientation of the camera are fixed.

3. The identification and positioning system for small-group weld seams according to claim 2, characterized in that: Two robotic arms are symmetrically arranged on the gantry frame, and two laser emitters are respectively mounted on the robotic arms. The central control system can control the movement of the two robotic arms respectively.

4. The identification and positioning system for small-group weld seams according to claim 3, characterized in that: The robotic arm is equipped with a welding torch at its end.

5. The identification and positioning system for small-group weld seams according to claim 3, characterized in that: The central control system controls the movement of the two robotic arms on both sides of the stiffening plate.

6. A method for identifying and locating small-group vertical welds, employing the identification and locating system for small-group vertical welds as described in any one of claims 1 to 5, characterized in that... Includes the following steps: S1. The vision system performs the first visual sensing detection on the workpiece to be welded, obtains the first image information of the workpiece to be welded, and identifies the outer contour and part number of the workpiece to be welded. S2. The initial image information is sent to the database of the central control system. The database retrieves the corresponding three-dimensional model of the workpiece to be welded. The central control system identifies the approximate location of the weld seam based on the comparison between the initial image information and the three-dimensional model. S3. The trajectory planning system plans the laser's motion trajectory based on the approximate location of the weld, so that the laser's movement range can cover the approximate location of the weld. The central control system controls the movement of the laser emitter based on the trajectory planned by the trajectory planning system, while the vision system continuously performs visual sensing detection on the workpiece to be welded. S4. When the vision system detects that the laser emitted by the laser emitter is deformed on the base plate of the workpiece to be welded, the beginning or end position of the weld can be located; in step S3, the motion trajectory starts from the middle section of the approximate position of the weld and moves along the approximate position of the weld toward the beginning or end position of the approximate position of the weld, and the motion trajectory covers the beginning or end position of the approximate position of the weld.

7. The method for identifying and locating sub-group welds according to claim 6, characterized in that: In step S3, the overall control system first controls the movement of the laser emitter on the left side of the rib plate according to the trajectory planned by the trajectory planning system, and then controls the movement of the laser emitter on the right side of the rib plate.

8. The method for identifying and locating sub-group welds according to claim 7, characterized in that: In step S4, the vision system visually detects the position of the laser deformation of the welds on the left and right sides of the stiffening plate, respectively, in order to locate the beginning or end position of the welds on the left and right sides of the stiffening plate.

9. The method for identifying and locating sub-group welds according to claim 6, characterized in that: Before step S1, there is step S0: establishing a first coordinate system and a second coordinate system. The first origin of the first coordinate system is set at the bottom end of the gantry. The direction of conveying the workpiece to be welded is the positive direction of the X1 axis. The direction from the bottom end of the gantry to the roller conveyor is the positive direction of the Y1 axis, and the vertical upward direction is the positive direction of the Z1 axis. The second origin of the second coordinate system is set at the end on the same side as the origin of the first coordinate system at the entrance of the roller conveyor plane. The positive directions of the X2 axis, Y2 axis, and Z2 axis are the same as the positive directions of the X1 axis, Y1 axis, and Z1 axis. The coordinates of the first origin in the second coordinate system are (a, b, c). In step S4, the coordinates of the position of the weld head or tail in the first coordinate system are (a1, b1, c1). The main control system converts the coordinates of the weld head position into coordinates (a+a1, b+b1, c+c1) in the second coordinate system.

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