JP3307475B2 - Automatic welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to automatic welding by a welding robot, and particularly to, but not limited to, automatically welding a fillet portion such as a seal of a cooling pipe for a blast furnace stave cooler by a welding robot. It is about the method.

[0002]

2. Description of the Related Art Conventionally, in seal welding of a stove cooler cooling pipe for a blast furnace, the pipe position and the number differ depending on the type of stave cooler, and since the pipe is fixed by casting, the pipe position has an error with respect to the drawing dimension position. Therefore, automation is difficult, and it is common practice to perform the welding by hand welding. As a method for solving such a problem, for example, Japanese Patent Application Laid-Open No. 58-141864 discloses a method in which drawing information is converted into numerical data, and the first teaching data is created in correspondence with the three-dimensional coordinates of the welding robot. Further, image information of the welding target is input by a television camera, the image information is converted into numerical data, and second data is created in correspondence with the three-dimensional coordinates of the welding robot. An automatic welding method is described in which the first teaching data is compared by a comparator, and the installation position of the welding object is changed based on the difference signal to correct the second teaching data.

[0003]

However, in the above-mentioned method, it is necessary to match the operation trajectory of the robot with the welding line on the CAD drawing, so that it is necessary to devise a drawing such as continuous drawing of the welding line. In addition, in order to obtain three-dimensional image data of an object to be welded, it is necessary for an operator to use a laser pointer to irradiate a predetermined portion of the object with a laser beam and to detect the laser spot with a television camera. In addition, there is an inconvenience that a work for each work change occurs.

An object of the present invention is to provide an automatic welding method capable of executing a welding operation in response to a change of a workpiece by a simple operation after inputting CAD graphic data. The purpose is to do.

According to the present invention, a figure of a work to be welded by a robot is preliminarily systematized as a symbol figure.
At the time of welding, at the time of welding, a figure of the workpiece itself is extracted from the CAD figure information , and the figure is
Link with the symbol figure that was created, extract only the figure data that matches the symbol figure, and create a symbol figure file .
Form, the symbol graphic file, by linking condition data file that defines such welding conditions necessary for creating a robot control data to create a work data, further, the work data, macro work procedures consistent robot Robot control data is automatically created by expanding the robot operation macro description file according to the described macro description, and the data is input to the welding robot control mechanism to operate the welding robot torch to perform automatic welding. FIG. 1 shows a data flow until robot control data is obtained.

[0006]

According to a link file, a symbol graphic file is developed according to a macro description of a robot operation macro description file in which a consistent robot operation procedure is macro-described. Therefore, when a welding target is changed, a symbol graphic of a new welding target is obtained. By selecting a file, robot control data of the new welding object is automatically generated. When the welding object is changed, the operator only has to select the symbol figure file, and the operation of the operator when changing the work is simplified.

[0007]

FIG. 2 shows an outline of an automatic welding system for implementing the present invention in one embodiment. In FIG. 2, an operator transfers CAD data recorded on a floppy disk 1 to a personal computer 2.
Is downloaded, the robot control data is automatically generated, and the robot control data is transmitted to the robot control device 3. Robot 4 based on the transmitted robot control data
Performs seal welding of the stave cooler. The positional deviation of the work is detected by the television camera 5 for image processing and the laser sensor 6 for length measurement, and the robot operation program is corrected based on the data to weld an accurate position.

In the welding system having the above configuration, the personal computer can check and change the work information by extracting only the information necessary for the welding work from the input CAD data and displaying it on the display on the personal computer. And In a template matching method using image processing for correcting positional displacement in the planar direction, a 1/4 circle of the seal ring is used as a template, so that even if the positional displacement of the work is large, it is possible to detect even a large positional displacement. To minimize detection and improve detection accuracy. The displacement and inclination of the seal ring in the height direction
It is corrected by measuring the height of four points on the seal ring.

Next, embodiments of the present invention will be described more specifically. FIG. 3 is a seal welding portion of a stove cooler cooling pipe welded according to the present invention. A seal ring 9 is inserted between the inner pipe 7 and the outer pipe 8, and the inner circumference and the outer circumference of the seal ring are welded to the entire circumference. FIG. 4 illustrates in more detail an automatic welding system that embodies the invention in one aspect. In the figure, CAD data is supplied to a personal computer 2 on a floppy disk. The input data is subjected to the following processing, converted into robot control data, and transmitted to the robot control device 3. That is, conditions necessary for creating robot control data are defined in a symbol figure file created by extracting figure data matching a specific symbol figure to be worked by a robot registered in advance in the system from CAD figure information. The robot control data is automatically created by expanding the work data created by linking the created condition data files in accordance with the macro description of the robot operation macro description file in which the consistent robot work procedure is macro-described.

The robot 4 has a welding torch 10 mounted on a wrist axis, and travels by a traveling device 11. TV camera 5 for image processing and laser sensor 6 for height measurement
Is mounted on the robot wrist axis. Work table 12
Has a tilting device for leveling the seal ring welding surface, and automatically tilts based on angle information obtained from CAD data. The personal computer 2 has software including a front processor for processing CAD drawing data and a post-processor for generating robot control data from the processed graphic information.

FIG. 5 shows data processing items of a front processor section for extracting information necessary for generating robot control data from CAD data and performing pre-processing of the data. In STEP 1 shown in FIG. 5, only graphic data matching the symbol graphic necessary for the welding work registered in the system in advance is extracted from the CAD drawing data to generate a symbol graphic file. In STEP 2, the extracted symbol graphic data is rearranged in accordance with the welding order definition file. In STEP3, the robot coordinates are CA
A coordinate reference point serving as a reference when converting the D drawing coordinates is defined and added as an attribute to the graphic data. STEP4
Generates a link file that defines the relationship between the symbol figure file and the condition data file that defines the welding conditions required to generate the robot control data, and gives the project name and part name as attributes to the hard disk or floppy disk. Output to

FIG. 6 shows data processing items of a post-processor section for generating robot control data based on a link file created by a front processor. FIG.
In STEP1, a link file generated by the front processor is read using the project name and the part name as keys. In STEP2, reference coordinates which are coordinates of the robot operation are set and recorded as a reference coordinate file. In STEP 3, the robot operation speed and the welding torch angle used in the macro processing developed in STEP 5 are checked, and correction is performed if necessary. In STEP 4, based on the symbol graphic file and the reference coordinate file, the symbol graphic on the CAD coordinate is coordinate-converted into the coordinate value on the robot coordinate. In STEP5, the symbol graphic file subjected to the coordinate conversion in STEP4 and the related data confirmed and corrected in STEP3 are developed according to the macro description of the robot operation macro description file.
Output to the hard disk in the personal computer as robot control data. In STEP 6, the robot control data generated in STEP 5 is transmitted to the robot control device.

The positional displacement of the cooling pipe with respect to the drawing data is detected by using a template matching technique in image processing, and the robot control data is corrected based on the data. The template is easily estimated to use the shape of the entire seal ring, which is the welding target. However, if the entire seal ring is used as a template, an image coincidence detection error due to the inclination of the pipe is likely to occur, and the relative per pixel There is a problem that the size (the size of the actual thing corresponding to one pixel on the image) becomes large and the detection error becomes large. In order to solve such a problem, the template is made to be a quarter circle of the seal ring to minimize the relative size and to minimize the image recognition error due to the inclination of the cooling pipe.

FIG. 7 shows an area of the positional deviation amount which can be recognized within the detection accuracy of ± 0.5 mm.
By adopting a circular template, position recognition can be performed in a wider range than when the entire seal ring is used as a template.

The positional deviation and inclination of the seal ring in the height direction are measured by the laser sensor 6 using the circumference 4 of the seal ring.
Detecting by measuring the height of several places, the welding torch work trajectory of the robot control data is corrected based on the data.

The tilt angle of the work table 12 is controlled as the eighth axis of the robot controller, and is automatically set by inputting the tilt angle of the stave cooler from the CAD data so that the seal ring welding surface is horizontal. I do. With the above apparatus, seal welding of the cooling pipe for the stave cooler is automatically executed.

[0017]

As described above, according to the present invention, the welding of the fillet portion can be performed by a simple operation on a personal computer, and there is no need for teaching for each type change, and a welding work with good workability can be performed. realizable.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a flow of data until robot control data is obtained in the present invention.

FIG. 2 is a perspective view showing an outline of an automatic welding system that implements the present invention in one aspect.

FIG. 3 shows a welding target 1 of the automatic welding system shown in FIG.
It is a perspective view which shows the external appearance of one step cooler.

FIG. 4 is a more detailed perspective view of an automatic welding system that embodies the invention in one aspect.

5 is a plan view showing data processing items from CAD drawing data input to link file generation shown in FIG.

FIG. 6 is a plan view showing data processing items from reading of a link file to generation of robot control data shown in FIG.

FIG. 7 is a diagram showing the amount of deviation allowed for image recognition by template matching when the photographing range of the step color by the television camera 5 shown in FIG. FIG.

[Explanation of symbols]

1: Floppy disk 2: Personal computer 3: Robot controller 4: Robot 5: TV camera for image processing 6: Laser sensor for length measurement 7: Inner pipe 8: Outer pipe 9: Seal ring 10: Welding torch 11: Traveling device 12 : Work table

Continued on the front page (72) Inventor Yoshikazu Hakoda 46-59 Ohara Nakahara, Tobata-ku, Kitakyushu Nippon Steel Corporation Technology Development Division (72) Inventor Eiji Sasaki 2 Tobihata-cho, Tobata-ku, Kitakyushu-shi -2 Within Nippon Steel Elex Co., Ltd. (72) Inventor Yasuyuki Tabu 46-59 Nakahara, Tobata-ku, Kitakyushu City Inside Nippon Plant Design Co., Ltd. (72) Shinji Tanemori 46, Ohara Nakahara, Tobata-ku, Kitakyushu-shi -59 Nippon Steel Plant Design Co., Ltd. (72) Inventor Shigemasa Hisaya 2-1 Kurosaki Shiroishi, Yawatanishi-ku, Kitakyushu City Inside Yasukawa Electric Co., Ltd. (56) References JP-A-6-337711 (JP, A JP-A-5-46226 (JP, A) JP-A-3-155470 (JP, A) JP-A-62-267086 (JP, A) JP-A-59-118277 (JP, A) 73123 (JP, A) JP-A-6-214625 (JP, A) JP-A-6-39661 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 9/127 B23K 9 / 12 B25J 13 / 00 G05B 19/4093

Claims (2)

(57) [Claims] 1. Being a robot work target in advance
Register the shape of the workpiece as a symbol shape in the system
While, the time of welding, the from the graphic information of CAD
The figure of the weldment itself is extracted, and the figure is
Is linked with Boll shape, creates a symbol graphic file by extracting only graphic data that matches the symbol graphic, the
Link a symbol data file with a condition data file that defines the welding conditions required for creating robot control data
It is allowed to create a work data, further, the work data, automatically creates the robot control data by deploying accordance macro description of the robot operation macro description files macro describing the operating procedure consistent robot, the data The automatic welding method characterized in that the automatic welding is performed by operating the welding robot control mechanism and operating the torch of the welding robot. 2. A planar displacement of an object to be welded is detected by using a template matching method in image processing, and a deviation and an inclination in a height direction of the object to be welded are detected by a laser sensor. 2. The automatic welding method according to claim 1, wherein the robot control data is corrected based on the data.