Automatic welding method for boiler membrane wall

Abstract

The invention relates to an automatic welding method for a boiler membrane wall, which comprises a laser vision sensor and a welding device, and is characterized in that the position of a welding spot of a welding seam is detected by one laser vision sensor, information of the other three welding seams can be obtained through processing and calculation, and additional vision identification equipment is not needed; and welding seams are accurately aligned by moving the welding gun, so that the four welding seams can be automatically welded, the welding efficiency is effectively improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of automatic welding, in particular to an automatic welding method for a boiler membrane wall. Background Art

[0002] In the existing technology, with the acceleration of the pace of industrial modernization in my country, welding technology and welding level have been rapidly developed and improved. Visual recognition and tracking welding technology has penetrated into all walks of life and all links of industrial production. The weld tracking visual sensor stands out among many sensors with its non-contact, high stability and clear and intuitive images. It has become one of the most widely used sensors in the welding field. The boiler membrane wall is a common boiler wall structure. It is a wall structure composed of a series of parallel vertical metal tubes. These metal tubes form a membrane wall. The high-temperature flue gas in the combustion process in the boiler passes through these pipes and transfers heat to the water or steam in them.

[0003] However, in the actual production process, a visual recognition device can only track one weld at a time, and the machine can only perform welding operations on one weld at a time. If you want to perform simultaneous welding of multiple welds on a workpiece such as a boiler membrane wall with multiple welds, you can only do so by adding visual recognition equipment, which will undoubtedly significantly increase the cost of the equipment. Summary of the invention

[0004] In order to solve the above problems, the present invention provides an automatic welding method for boiler membrane wall, which detects a position through a laser vision sensor to realize automatic welding of four welds, effectively improves welding efficiency and reduces production costs.

[0005] In order to achieve the above-mentioned purpose, the automatic welding method of the boiler membrane wall designed by the present invention includes a laser vision sensor and a welding device, wherein the laser vision sensor includes a laser emitter for emitting a linear laser to a workpiece to be welded, a camera for acquiring an image of the intersection of the laser line and the workpiece weld, and an image processing module for processing the image of the intersection of the laser line and the workpiece weld acquired by the camera to obtain the position of the welding point, and the welding device includes a first welding gun, a second welding gun, a third welding gun and a fourth welding gun arranged corresponding to the four welds of the workpiece, and welding is performed according to the following steps:

[0006] S1. The laser transmitter, camera and image processing module are installed on the moving path of the workpiece and remain stationary, while ensuring that the camera can obtain an image of the intersection of the laser line and the boiler membrane wall weld;

[0007] S2. The first welding gun and the second welding gun are installed on the path where the workpiece moves and are located in front of the laser vision sensor, the third welding gun and the fourth welding gun are installed on the path where the workpiece moves and are located between the first welding gun and the second welding gun, and the first welding gun, the second welding gun, the third welding gun and the fourth welding gun are configured to move and align with the weld according to the welding point position calculated by the image processing module;

[0008] S3. Calculate the positions of the remaining three welding points based on the known workpiece information and the welding point positions calculated by the image processing module;

[0009] S4. The first welding gun, the second welding gun, the third welding gun and the fourth welding gun move accordingly according to the welding point positions calculated in step S3, so that all points on the weld of the workpiece move under the welding guns to complete the welding.

[0010] A further solution is that in step S2, the first welding gun and the second welding gun are arranged parallel to each other and located above the workpiece, the third workpiece and the fourth workpiece are arranged parallel to each other and located below the workpiece, and the laser vision sensor is located on the same side of the third workpiece and the fourth workpiece.

[0011] A further solution is that in step S3, the positions of the remaining three welding points are calculated by the following steps based on the known workpiece information and the welding point positions calculated by the image processing module:

[0012] a. According to the known workpiece information, a mathematical model of the workpiece cross section is established to obtain Figure A, where: the length of the flat steel is L, the height is H, and the radius of the pipe is R; the contact point between the pipe and the flat steel surface is P; A1, A2, A3 and A4 are the positions of the four corners of the flat steel cross section; B1 and B2 are the projection positions of A1 and A2 along the upper surface of the flat steel on the surface of the pipe; B3 and B4 are the projection positions of A3 and A4 along the lower surface of the flat steel on the surface of the pipe;

[0013] b. According to Figure A combined with the known image processing module to calculate the welding point position A1, we get:

[0014] A1=(0,y A1 ,z A1 ),

[0015] B1=(0,y B1 ,z B1 ),

[0016] P=(0,y P ,z P ),

[0017]

[0018] c. Calculate A2B2, A3B3, A4B4 according to the following formula:

[0019]

[0020] θ=asin(R / (z A2 -z P )),

[0021] Then B2=(0,y p -R(1-cosθ),z P -R*sinθ),

[0022] The positions of B3 and B4 can be obtained in the same way;

[0023] d. According to A1B1, A2B2, A3B3, A4B4, the four welding positions are:

[0024]

[0025] A further solution is that in step S4, the first welding gun, the second welding gun, the third welding gun and the fourth welding gun are moved according to the welding point positions calculated in step S3 and in the following steps:

[0026] A. Before welding, first aim the first welding gun and the second welding gun at the two welding seams on the upper side of the workpiece, and reset the positions of the first welding gun and the second welding gun;

[0027] B. Assume that the welding positions of the first welding gun and the second welding gun at time i are:

[0028]

[0029] When Ci=0, the calculation starts. When i=n, ​​a total of n groups of W data are calculated. At this time, the n groups of data are averaged and filtered: and the result is recorded as W B :

[0030]

[0031] Where n = 9;

[0032] D. Welding starts, the workpiece starts to move, at time i, the positions where the first welding gun and the second welding gun should move are:

[0033]

[0034] E. When the workpiece moves to the working area of ​​the third welding gun and the fourth welding gun, aim the third welding gun and the fourth welding gun at the two welding seam positions on the lower side of the workpiece respectively, and the positions of the third welding gun and the fourth welding gun are reset;

[0035] F. At this time, the first welding gun, the second welding gun, the third welding gun and the fourth welding gun work simultaneously for welding, and the positions of the first welding gun, the second welding gun, the third welding gun and the fourth welding gun are respectively:

[0036]

[0037] Wherein, T is the time taken for the workpiece to move from the first welding gun and the second welding gun to the third welding gun and the fourth welding gun.

[0038] The automatic welding method of the boiler membrane wall designed by the present invention detects the position of a weld point through a laser vision sensor, and obtains the information of the remaining three welds through processing and calculation. No additional visual recognition equipment is required, and the weld can be accurately aligned by moving the welding gun to realize automatic welding of four welds, thereby effectively improving welding efficiency and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the welding state of Example 1;

[0040] Figure 2 It is Figure A in Example 1;

[0041] Figure 3 This is the B2 position model diagram in Example 1. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0043] Example 1.

[0044] like Figure 1 As shown, the automatic welding method of the boiler membrane wall described in this embodiment includes a laser vision sensor and a welding device, wherein the laser vision sensor includes a laser emitter for emitting a linear laser to a workpiece to be welded, a camera for acquiring an image of the intersection of the laser line and the weld of the workpiece, and an image processing module for processing the image of the intersection of the laser line and the weld of the workpiece acquired by the camera to obtain the position of the welding point, and the welding device includes a first welding gun, a second welding gun, a third welding gun and a fourth welding gun arranged corresponding to the four welds of the workpiece, and the welding is performed according to the following steps: S1. The laser emitter, the camera and the image processing module are installed on the moving path of the workpiece and remain stationary, and at the same time ensure that the camera can acquire an image of the intersection of the laser line and the weld of the boiler membrane wall;

[0045] S2. The first welding gun and the second welding gun are installed on the path where the workpiece moves and are located in front of the laser vision sensor, the third welding gun and the fourth welding gun are installed on the path where the workpiece moves and are located between the first welding gun and the second welding gun, and the first welding gun, the second welding gun, the third welding gun and the fourth welding gun are configured to move and align with the weld according to the welding point position calculated by the image processing module;

[0046] S3. Calculate the positions of the remaining three welding points based on the known workpiece information and the welding point positions calculated by the image processing module;

[0047] S4. The first welding gun, the second welding gun, the third welding gun and the fourth welding gun move accordingly according to the welding point positions calculated in step S3, so that all points on the weld of the workpiece move under the welding guns to complete the welding.

[0048] A further solution is that in step S2, the first welding gun and the second welding gun are arranged parallel to each other and are located above the workpiece, the third workpiece and the fourth workpiece are arranged parallel to each other and are located below the workpiece, and the laser vision sensor is located on the same side of the third workpiece and the fourth workpiece. Using this structural layout, Figure 1 As shown, the laser vision sensor is located on the welding back side of the first welding gun and the second welding gun and is separated from the third workpiece and the fourth workpiece on the same side. It can effectively solve the spatter problem generated during the gas shielded welding process to prevent the spatter from interfering with the work of the vision sensor, thereby ensuring the stability and reliability of the welding process.

[0049] A further solution is that in step S3, the positions of the remaining three welding points are calculated by the following steps based on the known workpiece information and the welding point positions calculated by the image processing module:

[0050] a. According to the known workpiece information, a mathematical model of the workpiece cross section is established to obtain Figure A, where: the length of the flat steel is L, the height is H, and the radius of the pipe is R; the contact point between the pipe and the flat steel surface is P; A1, A2, A3 and A4 are the positions of the four corners of the flat steel cross section; B1 and B2 are the projection positions of A1 and A2 along the upper surface of the flat steel on the surface of the pipe; B3 and B4 are the projection positions of A3 and A4 along the lower surface of the flat steel on the surface of the pipe;

[0051] b. According to Figure A combined with the known image processing module to calculate the welding point position A1, we get:

[0052] A1=(0,y A1 ,z A1 ),

[0053] B1=(0,y B1 ,z B1 ),

[0054] P=(0,y P ,z P ),

[0055]

[0056] c. Calculate A2B2, A3B3, A4B4 according to the following formula:

[0057]

[0058] θ=asin(R / (z A2 -z P )),

[0059] Then B2=(0,y p -R(1-cosθ),z P -R*sinθ), such as Figure 3 As shown,

[0060] The positions of B3 and B4 can be obtained in the same way;

[0061] d. According to A1B1, A2B2, A3B3, A4B4, the four welding positions are:

[0062]

[0063] A further solution is that in step S4, the first welding gun, the second welding gun, the third welding gun and the fourth welding gun are moved according to the welding point positions calculated in step S3 and in the following steps:

[0064] A. Before welding, first aim the first welding gun and the second welding gun at the two welding seams on the upper side of the workpiece, and reset the positions of the first welding gun and the second welding gun;

[0065] B. Assume that the welding positions of the first welding gun and the second welding gun at time i are:

[0066]

[0067] When Ci=0, the calculation starts. When i=n, ​​a total of n groups of W data are calculated. At this time, the n groups of data are averaged and filtered: and the result is recorded as W B :

[0068]

[0069] Where n = 9;

[0070] D. Welding starts, the workpiece starts to move, at time i, the positions where the first welding gun and the second welding gun should move are:

[0071]

[0072] E. When the workpiece moves to the working area of ​​the third welding gun and the fourth welding gun, aim the third welding gun and the fourth welding gun at the two welding seam positions on the lower side of the workpiece respectively, and the positions of the third welding gun and the fourth welding gun are reset;

[0073] F. At this time, the first welding gun, the second welding gun, the third welding gun and the fourth welding gun work simultaneously for welding, and the positions of the first welding gun, the second welding gun, the third welding gun and the fourth welding gun are respectively:

[0074]

[0075] Wherein, T is the time taken for the workpiece to move from the first welding gun and the second welding gun to the third welding gun and the fourth welding gun.

[0076] The automatic welding method for the boiler membrane wall provided in this embodiment detects the position of a weld point through a laser vision sensor, and obtains the information of the remaining three welds through processing and calculation. No additional visual recognition equipment is required, and the weld can be accurately aligned with the moving welding gun to achieve automatic welding of four welds, effectively improving welding efficiency and reducing production costs.

[0077] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "horizontal", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0078] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0079] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An automatic welding method for a boiler membrane wall, comprising a laser vision sensor and a welding device, characterized in that: The laser vision sensor includes a laser emitter for emitting a linear laser to a workpiece to be welded, a camera for acquiring an image of the intersection of the laser line and the weld of the workpiece, and an image processing module for processing the image of the intersection of the laser line and the weld of the workpiece acquired by the camera to obtain the position of the welding point. The welding device includes a first welding gun, a second welding gun, a third welding gun and a fourth welding gun arranged corresponding to the four welds of the workpiece. The welding is performed according to the following steps: S1. The laser transmitter, camera and image processing module are installed on the moving path of the workpiece and remain stationary, while ensuring that the camera can obtain an image of the intersection of the laser line and the boiler membrane wall weld; S2. The first welding gun and the second welding gun are installed on the path where the workpiece moves and are located in front of the laser vision sensor, the third welding gun and the fourth welding gun are installed on the path where the workpiece moves and are located between the first welding gun and the second welding gun, and the first welding gun, the second welding gun, the third welding gun and the fourth welding gun are configured to move and align with the weld according to the welding point position calculated by the image processing module; S3. Calculate the positions of the remaining three welding points based on the known workpiece information and the welding point positions calculated by the image processing module; S4. The first welding gun, the second welding gun, the third welding gun and the fourth welding gun move accordingly according to the welding point positions calculated in step S3, so that all points on the weld of the workpiece move under the welding guns to complete the welding.

2. The automatic welding method for boiler membrane wall according to claim 1 is characterized in that: In step S2, the first welding gun and the second welding gun are arranged parallel to each other and located above the workpiece, the third workpiece and the fourth workpiece are arranged parallel to each other and located below the workpiece, and the laser vision sensor is located on the same side of the third workpiece and the fourth workpiece.

3. The automatic welding method for boiler membrane wall according to claim 1 is characterized in that: In step S3, the positions of the remaining three welding points are calculated according to the known workpiece information and the welding point positions calculated by the image processing module through the following steps: a. According to the known workpiece information, a mathematical model of the workpiece cross section is established to obtain Figure A, where: the length of the flat steel is L, the height is H, and the radius of the pipe is R; the contact point between the pipe and the flat steel surface is P; A1, A2, A3 and A4 are the positions of the four corners of the flat steel cross section; B1 and B2 are the projection positions of A1 and A2 along the upper surface of the flat steel on the surface of the pipe; B3 and B4 are the projection positions of A3 and A4 along the lower surface of the flat steel on the surface of the pipe; b. According to Figure A combined with the known image processing module to calculate the welding point position A1, we get: <h2 style=";text-align:left;direction:ltr">A1=(0,y<h2 style=";text-align:left;direction:ltr"> A1 <h2 style=";text-align:left;direction:ltr"> ,z<h2 style=";text-align:left;direction:ltr"> A1 <h2 style=";text-align:left;direction:ltr"> ), B1=(0,y B1 ,from B1 ), P=(0,y P ,z P ), c. Calculate A2B2, A3B3, A4B4 according to the following formula: θ=asin(R / (z A2 -z P )), Then B2 = (0, y p -R(1 - cosθ), z P -R * sinθ), The positions of B3 and B4 can be obtained in the same way; d. According to A1B1, A2B2, A3B3, A4B4, the four welding positions are:

4. The automatic welding method for boiler membrane wall according to claim 3 is characterized in that: In step S4, the first welding gun, the second welding gun, the third welding gun and the fourth welding gun are moved according to the welding point positions calculated in step S3 and in the following steps: A. Before welding, first aim the first welding gun and the second welding gun at the two welding seams on the upper side of the workpiece, and reset the positions of the first welding gun and the second welding gun; B. Assume that the welding positions of the first welding gun and the second welding gun at time i are: When Ci=0, the calculation starts. When i=n, ​​a total of n groups of W data are calculated. At this time, the n groups of data are averaged and filtered: and the result is recorded as W B : Where n = 9; D. Welding starts, the workpiece starts to move, at time i, the positions where the first welding gun and the second welding gun should move are: E. When the workpiece moves to the working area of ​​the third welding gun and the fourth welding gun, aim the third welding gun and the fourth welding gun at the two welding seam positions on the lower side of the workpiece respectively, and the positions of the third welding gun and the fourth welding gun are reset; F. At this time, the first welding gun, the second welding gun, the third welding gun and the fourth welding gun work simultaneously to weld, and the positions of the first welding gun, the second welding gun, the third welding gun and the fourth welding gun are respectively: Wherein, T is the time taken for the workpiece to move from the first welding gun and the second welding gun to the third welding gun and the fourth welding gun.

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