KR20240043269A - Automatic welding method for block inner materials of ships - Google Patents

Abstract

This is about an automatic welding method for ship block internals that uses LDS (Laser Displacement Sensor), a type of digital distance measuring sensor, to generate information about the shape of the groove joint and to enable efficient automated welding using this, one-dimensional Move the welding robot equipped with a laser distance sensor to the position of the welding line of the internal material of the Chosun block, obtain distance information about the cross section of the welding line using a one-dimensional laser distance sensor, and then convert the obtained distance information into line information to create a groove joint. (groove joint) shape information is generated, and based on the generated groove joint shape information, singularity and shape information for robot welding are created to determine the welding position, and the determined welding position information is reflected in the robot program (PGM) for shipbuilding. Proceed with welding the internal materials of the block.

Description

Automatic welding method for block inner materials of ships}

The present invention relates to an automatic welding method for the internal materials of a ship's block. In particular, information on the shape of the groove joint is generated using an LDS (Laser Displacement Sensor), a type of digital distance measuring sensor, and this allows efficient automated welding. This relates to an automatic welding method for internal block materials of ships.

When building a ship, mounting welding work is done block-to-block welding, and in the process, a large amount of internal materials such as T-bars within the block are welded. In order to weld the internal material of the mounting block, a small and lightweight welding robot has been developed. In order to weld the internal material using this welding robot, the welding area is shaped like a groove joint, which is a joint that engages with the groove that the welding robot must weld. must be recognized.

As a method for recognizing welding areas in the groove joint shape, non-contact sensors such as arc sensors or LVS (Laser Vision Sensor) are used.

When using an arc sensor, there is a disadvantage that it is technically difficult to implement multi-layer welding and that the location of the welding start point that can be recognized by the robot controller is required to be tracked.

In addition, in the case of LVS, a laser head including a sun laser, a camera, a reflecting mirror, and a spatter cover, a power supply and image signal controller, a controller that transmits signals, extracts information, and generates and transmits control input signals, and a power supply. A cable for signal transmission from the video signal controller, an LVS operation program, element control, image processing program, 3D metric conversion program, noise processing, and communication program are required.

Therefore, in the case of LVS, there is a disadvantage that the sensor hardware configuration is complex and the software that controls the hardware must also be difficult. In addition, commercially available LVSs are expensive, costing more than 100 million won, making it difficult to secure economic feasibility, and developing them with in-house technology requires specialized manpower and a long development period.

Meanwhile, a conventionally proposed technology for automating welding of curved block internal materials of ships is disclosed in <Patent Document 1> below.

The prior art disclosed in <Patent Document 1> is an automated device for welding the inner material of a curved block of a ship to automatically perform internal material welding on a section called U-cell inside the curved block of a ship, and is used to obtain shape information of the inner material. By using the side distance sensor and front distance sensor, and combining horizontal tilt, separation distance between equipment, vertical/horizontal tilt detection of frame members, and detection of separation distance between frame members and equipment, primary internal material shape information is obtained, Welding is performed by obtaining precise shape information of the member through secondary teaching.

However, this prior art does not use an expensive LVS, but uses a side distance sensor and a front distance sensor, and calculates horizontal/vertical tilt, separation distance between equipment, separation distance between members and equipment, etc. using their measurement information, This is used to derive the first member shape information and then obtain the member precise shape information through secondary teaching. Therefore, deriving the member shape information is very complicated and requires first and second teaching processes. There is a disadvantage that it takes a lot of time to derive member shape information.

Republic of Korea registered patent 10-1724424 (registered on April 3, 2017) (Automated device for welding internal materials of curved blocks of ships and its operation method)

Therefore, the present invention solves the problem that occurs when generating the shape information of the general shipbuilding block internal material groove joint as described above and the problem that occurs when generating the shape information of the shipbuilding block internal material through many sensors and multiple teaching processes in the prior art. As a solution, automatic welding of internal materials of ship blocks was proposed to generate information on the groove joint shape using LDS (Laser Displacement Sensor), a type of digital distance measuring sensor, and use this to enable efficient automated welding. The purpose is to provide a method.

In order to achieve the above-described object, the “automatic welding method for internal block materials of ships” according to the present invention,

(a) Step of moving the welding robot equipped with a one-dimensional laser distance sensor to the position of the welding line of the internal material of the Chosun block:

(b) obtaining distance information about the cross section of the weld line using the one-dimensional laser distance sensor;

(c) converting the obtained distance information into line information to generate groove joint shape information;

(d) determining a welding position by generating singular point and shape information for robot welding based on the generated groove joint shape information; and

(e) reflecting the determined welding position information in the robot program (PGM) to proceed with welding the internal materials of the shipbuilding block.

The one-dimensional distance sensor in step (a) above is characterized by using a micro laser displacement sensor (CMOS), which is a laser distance sensor (LDS).

In the above step (b), the distance information about the weld line cross section is characterized in that the distance information about the weld line cross section is acquired as point information while the welding robot moves about the weld line cross section.

In step (c) above,

The point information obtained in step (b) is converted into line information to generate groove joint shape information.

In step (c) above,

(c1) receiving point information as raw data through groove scanning using the one-dimensional laser distance sensor;

(c2) first filtering the input raw data using a median filter and secondarily filtering the input raw data using a Gaussian filter;

(c3) creating a virtual plane where scanning occurs based on the point data that has passed the Gaussian filter;

(c4) dividing the groove area in the created virtual plane;

(c5) performing Hough transformation based on the divided groove area information to generate groove joint shape information consisting of lines for the groove joint.

In step (c4) above,

It is characterized by calculating the displacement rate based on point data, finding the maximum/minimum displacement rate from the calculated displacement rate, finding four inflection points, and dividing the groove area in the virtual plane.

In step (c5) above,

It is characterized by finding the intersection between straight lines and generating groove joint shape information.

In step (d) above,

The welding position is determined by calculating a singular point for robot welding from the generated groove joint shape information.

According to the present invention, information on the shape of the groove joint is generated using an LDS (Laser Displacement Sensor), a type of digital distance measuring sensor, and using this, efficient automated welding of the internal materials of the shipbuilding block is possible, thereby eliminating the cost of expensive materials such as the existing LVS. It has the effect of resolving the difficulty in securing economic feasibility in using the equipment.

In addition, according to the present invention, the shape information of the groove joint can be generated with a simple hardware configuration of the controller without high-end CPU, VGA, cable, or communication hardware for image processing, thereby simplifying the configuration compared to existing technology and automatically improving the internal materials of the Chosun Block. It has the effect of reducing the cost of implementing a system for welding.

In addition, according to the present invention, only a distance sensor is required to recognize the shape of the weld zone, so it is easy to carry, and it can be easily installed on an automatic welding robot in the field to easily obtain shape information of the groove joint to be welded. there is.

In addition, since groove joint shape information can be generated using only a distance sensor and a controller, there is no need for a separate signal line cable, which has the effect of preventing the risk of interference or collision with work members during work.

1 is a diagram illustrating the configuration and shape of a welding robot applied to the present invention;
Figure 2 is an example of generating groove joint shape information using a micro laser displacement sensor in the present invention;
Figure 3 is a flow chart showing a method for automatically welding block internal materials of a ship according to the present invention;
Figure 4 is a flowchart of an embodiment of the process of generating groove joint shape information through LDS position recognition of Figure 3;
5A to 5C are raw data conversion graphs of the process of generating groove joint shape information in FIG. 4.

Hereinafter, a method for automatically welding block internal materials of a ship according to a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

The terms or words used in the present invention described below should not be construed as limited to their usual or dictionary meanings, and the inventor may appropriately define the concept of the term in order to explain his/her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it can be done.

Therefore, the embodiments described in this specification and the configurations shown in the drawings are only preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, and therefore various equivalents and It should be understood that variations may exist.

FIG. 1 is a diagram illustrating the configuration and shape of a welding robot according to a preferred embodiment of the present invention, and FIG. 2 is an illustrative diagram of generating groove joint shape information using a micro laser displacement sensor in the present invention.

In the present invention, the Laser Displacement Sensor (LDS) 11 for generating shape information of the groove joint of the shipbuilding block welded internal material (T-BAR) uses a micro laser displacement sensor (CMOS). The laser distance sensor 11 is a one-dimensional sensor. This one-dimensional laser distance sensor 11 can be mounted on a robot tool adapter (Tool adapter) of the welding robot (1).

Here, inside the welding robot 1, the point information of the weld line cross section acquired through the one-dimensional laser distance sensor 11 is converted into line information to generate groove joint shape information, and the singular point for robot welding is calculated to determine the welding position. After determining , it is assumed that a controller 13 that automatically controls robot welding is provided.

As shown in FIG. 2, this controller 13 uses the one-dimensional laser distance sensor 11 at the start of the welding operation to monitor the cross section of the weld line of the shipbuilding block internal material (e.g., T-BAR) 2. While moving the welding robot (1), scanning is performed to obtain distance information (longi, face) about the cross section. The distance information obtained in this way is point information, and is called raw data. Next, the controller 13 converts the acquired raw data of the weld line cross section into line information and generates line information about the weld line cross section (Longi, Web). The line information generated here becomes the shape information of the groove joint. To convert point information to line information, set the Macro OLP setting value. For example, set the web, lower scallop height, and upper hole height. Typically, face point information is obtained from the upper surface of the T-bar, which is an internal material, and web point information is obtained from the side of the T-bar.

The welding position is determined using the shape information of the groove joint created in this way, and this is reflected in the welding robot's program (PGM) to proceed with robot welding along the weld line.

This is explained in more detail as follows.

Figure 3 is a flowchart showing a method for automatically welding block internal materials of a ship according to the present invention, in which a one-dimensional laser distance sensor 11 is mounted on the robot tool adapter of the welding robot 1 (S101), and the welding robot 1 is Move to a certain position of the internal material weld line to be acquired.

If the moved location is the first Longi (S102), enter Longi information (S103). Here, the longage information may include the width and thickness of the face, the width and thickness of the web, the height of the scallop at the bottom of the face, and the height of the hole at the top of the face.

Next, the welding pass is calculated using the normal welding pass calculation method using the face thickness and web thickness information (S104), and the welding pass of the face and web is determined based on the calculated welding pass information. (S105).

Next, a robot program (PGM) for welding control of the welding robot 1 is created (S106), and welding work of the welding robot 1 is started (S107).

When the work of the welding robot begins, the welding robot moves with respect to the cross section of the weld line of the T-bar, which is an internal material, and obtains distance information about the cross section of the weld line 2 using the one-dimensional laser distance sensor 11. , The acquired point distance information is transmitted to the controller 13 through internal EtherCAT communication. The controller 13 converts the obtained point distance information into line information and generates groove joint shape information (S108).

For example, here, the distance information about the weld line cross section is acquired as point information while the welding robot 1 moves about the weld line cross section.

Next, the obtained distance information is converted into line information to generate groove joint shape information.

In other words, as shown in FIG. 4, point information is input as raw data through groove scanning using the one-dimensional laser distance sensor 11 (S121). Figure 5a is an example of the raw data. Next, the input raw data is first filtered using a median filter. Figure 5b is an example of the result of first filtering the raw data using a median filter. Next, the raw data first filtered with the median filter is secondarily filtered with a Gaussian filter (S122). Figure 5c is an example of the result of secondary filtering using the Gaussian filter. Next, a virtual plane where scanning occurs is found based on the point data that has passed the Gaussian filter. In other words, a virtual plane where scanning occurs is created (S123). Next, the groove area is divided in the created virtual plane (S124). In other words, the displacement rate is calculated based on the point data, the maximum/minimum displacement rate is found from the calculated displacement rate, four inflection points are found, and the groove area is divided in the virtual plane. Finally, Hough Transform is performed based on the divided groove area information to generate groove joint shape information consisting of lines for the groove joint (S125). In other words, the intersection between straight lines is found and groove joint shape information is generated.

Next, a singular point for robot welding is calculated based on the generated groove joint shape information, and the shape information is generated to determine the welding position (S109).

Next, the determined welding position information is reflected in the generated robot program (PGM) to proceed with welding the internal materials of the shipbuilding block (S110, S111).

According to the present invention described above, information on the groove joint shape can be generated using a low-cost LDS (Laser Displacement Sensor), a type of digital distance measuring sensor, thereby ensuring economic efficiency compared to using expensive equipment such as existing LVS. difficulties can be solved.

In addition, the shape information of the groove joint can be generated with only a simple hardware configuration of the controller without the need for high-end CPU, VGA, cable, or communication hardware for image processing, making it a system for automatic welding of internal materials of shipbuilding blocks while simplifying the configuration compared to existing technologies. Implementation costs can be reduced.

In addition, since only a distance sensor is needed to recognize the shape of the weld zone, it is easy to carry, and can be easily installed on an automatic welding robot in the field to easily obtain shape information of the groove joint to be welded.

In addition, since it is possible to generate groove joint shape information using only a distance sensor and a controller, there is no need for a separate signal line cable, preventing the possibility of interference or collision with work members during work.

Although the invention made by the present inventor has been described in detail according to the above embodiments, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the invention, as is known in the art. It is self-evident to those who have.

1: Welding robot
2: Internal material (weld line)
11: Laser distance sensor
12: solenoid
13: Controller

Claims (8)

One-dimensional laser distance sensor LDS for generating shape information of the groove joint of the shipbuilding block welded internal material (T-BAR); The Laser Displacement Sensor is mounted on the robot tool adapter of the welding robot, and the point information of the weld line cross section acquired through the one-dimensional laser distance sensor is converted into line information to generate groove joint shape information and singularity for robot welding. After determining the welding position by calculating
(a) Step of moving the welding robot equipped with a one-dimensional laser distance sensor to the position of the welding line of the internal material of the Chosun block:
(b) acquiring distance information about the cross section of the weld line using the one-dimensional laser distance sensor;
(c) converting the distance information obtained from the controller into line information to generate groove joint shape information;
(d) determining a welding position by generating singular point and shape information for robot welding based on the groove joint shape information generated by the controller; and
(e) A method of automatically welding the internal materials of a ship's block, comprising the step of welding the internal materials of the shipbuilding block by reflecting the welding position information determined by the controller in the robot program (PGM).
In claim 1, the one-dimensional laser distance sensor (LDS) in step (a) is a method of automatically welding block internal materials of a ship, characterized in that using a micro laser displacement sensor (CMOS).
In claim 1, the distance information about the weld line cross section in step (b) is an automatic welding method for block internal materials of a ship, characterized in that the distance information about the weld line cross section is acquired as point information while the welding robot moves with respect to the weld line cross section. .
In claim 1, step (c) includes,
An automatic welding method for block internal materials of a ship, characterized in that the point information obtained in step (b) is converted into line information to generate groove joint shape information.
In claim 1, step (c) includes,
(c1) receiving point information as raw data through groove scanning using the one-dimensional distance sensor;
(c2) first filtering the input raw data using a median filter and secondarily filtering the input raw data using a Gaussian filter;
(c3) creating a virtual plane where scanning occurs based on the point data that has passed the Gaussian filter;
(c4) dividing the groove area in the created virtual plane; and
(c5) An automatic welding method for block internal materials of a ship, comprising the step of generating groove joint shape information consisting of lines for the groove joint by performing Hough transformation based on the divided groove zone information.
In claim 5, step (c4) is,
An automatic welding method for internal block materials of ships, characterized by calculating the displacement rate based on point data, finding the maximum/minimum displacement rate from the calculated displacement rate, finding four inflection points, and dividing the groove area in the virtual plane.
In claim 5, step (c5) is,
An automatic welding method for internal block materials of ships, characterized by finding the intersection between straight lines and generating groove joint shape information.
In claim 1, step (d) is,
An automatic welding method for block internal materials of a ship, characterized in that the welding position is determined by calculating a singular point for robot welding from the generated groove joint shape information.

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