CN110475649B

CN110475649B - Operation program correction method, structure assembly method, medium, and welding robot system

Info

Publication number: CN110475649B
Application number: CN201880019898.3A
Authority: CN
Inventors: 宫田俊介; 定广健次; 焦有卓; 木村雄士
Original assignee: Kobe Steel Ltd
Current assignee: Kobe Steel Ltd
Priority date: 2017-03-21
Filing date: 2018-02-27
Publication date: 2022-08-16
Anticipated expiration: 2038-02-27
Also published as: CN110475649A; WO2018173655A1; JP2018153905A; KR20190120283A; KR102315485B1; JP6914067B2

Abstract

An operation program correction method for correcting an operation program of a welding robot (1) that welds a member (W) to be welded, comprising: extracting data of a predetermined member to be welded (W) from the three-dimensional CAD data; a step in which a sensor images a member (W) to be welded that is positioned and arranged by a welding robot (1); a step of acquiring a plurality of surfaces from the data of the photographed members (W) to be welded; a step of acquiring a maximum surface having a maximum area among the plurality of surfaces; a step of extracting at least two vertices (X1, X2) on the maximum surface; a step in which a camera (12) images a member (W) to be welded that is positioned and arranged by a welding robot (1); extracting two intra-image vertexes corresponding to the two vertexes from the captured image data of the member to be welded (W); a step of obtaining a difference between the coordinates of the two vertices (X1, X2) and the coordinates of the vertices within the two images; and correcting an operation program for operating the welding robot (1) on the basis of the difference.

Description

Operation program correction method, structure assembly method, medium, and welding robot system

Technical Field

The present invention relates to an operation program correction method and a welding robot system for correcting an operation program of a welding robot for welding a member to be welded.

Background

Robots are currently used in various industrial fields. A welding robot is known as a representative of such industrial robots. In the welding work, it is necessary to set an optimum welding condition according to each construction condition, and there are many elements, parameters, and combinations thereof in the setting of the construction condition and the welding condition.

Patent document 1 provides a walking robot and a control method thereof, which can simplify the operation programming of the robot when welding a large member having a complicated shape or the like. An articulated robot having a rotation shaft is provided with a travel shaft, a traverse shaft, a lift shaft, and a rotation shaft as external shafts, and is caused to perform a predetermined operation such as a welding operation while being moved by the articulated robot via the external shafts.

Patent document 2 provides a welding robot apparatus for a large frame structure, which can perform main welding on an intersection of the large frame structure in which a vertical member and a horizontal member are formed on a panel in an intersecting manner, has few restrictions on a welding portion for the main welding, basically does not require manual welding, can miniaturize the entire apparatus as compared with a conventional multi-robot welding apparatus using a large gantry structure, and does not require a complicated control system. The welding robot apparatus of patent document 2 includes: a robot mount having a horizontal support mount positioned above a welding target region, the welding target region being defined by a lattice-shaped frame surrounded by a pair of vertical members and a pair of horizontal members, the robot mount being fixed to the large-sized frame structure so as to straddle the welding target region; and a welding robot which is attached to the lower surface of the horizontal support frame and which performs three-dimensional numerical control of the welding head over the entire range of the lattice-shaped frame (welding target region) so as to enable welding.

Prior art documents

Patent document

Patent document 1: japanese laid-open patent publication No. 2000-246677

Patent document 2: japanese patent application laid-open No. 2010-253518

Disclosure of Invention

Problems to be solved by the invention

However, the operation program of the welding robot is determined on the premise that the member to be welded, which is the welding target, is positioned at a predetermined position. However, in actual welding work, the position of the member to be welded is not necessarily arranged at a predetermined position assumed in advance, and when such a member to be welded is arranged at a position deviated from the predetermined position, there is a possibility that the welding work may be failed.

The present invention relates to an operation program correction method and a welding robot system capable of appropriately correcting an operation program of a welding robot according to an actual arrangement position of a member to be welded.

Means for solving the problems

The present invention is an operation program correction method for correcting an operation program of a welding robot for welding a member to be welded, including: extracting data of a predetermined member to be welded from the three-dimensional CAD data; a step of acquiring a plurality of surfaces from the data of the extracted members to be welded; a step of acquiring a maximum face having a maximum area among the plurality of faces; a step of extracting at least two vertices on the maximum surface; a step in which a sensor images the member to be welded, which is positioned and arranged by a welding robot; extracting two intra-image vertexes corresponding to the two vertexes from the captured image data of the member to be welded; a step of obtaining a difference value between the coordinates of the two vertexes and the coordinates of the vertexes in the two images; and correcting an operation program for operating the welding robot based on the difference value.

The present invention is a welding robot system including: a welding robot that welds a member to be welded; and a computer that controls an operation of the welding robot in accordance with a predetermined operation program, the computer executing: the method includes extracting data of a predetermined member to be welded from three-dimensional CAD data, acquiring a plurality of surfaces from the extracted data of the member to be welded, acquiring a largest surface having a largest area among the plurality of surfaces, extracting at least two vertices on the largest surface, acquiring an image of the member to be welded, which is positioned and arranged by a welding robot, captured by a sensor, extracting two in-image vertices corresponding to the two vertices from the captured image data of the member to be welded, acquiring a difference between coordinates of the two vertices and coordinates of the two in-image vertices, and correcting the operation program based on the difference.

Effects of the invention

According to the present invention, since the operation program of the welding robot can be corrected based on the actual arrangement position of the member to be welded, the welding robot operates according to the operation program after the appropriate correction, and an appropriate welding operation can be ensured.

Drawings

Fig. 1 is a schematic configuration diagram of a welding robot system according to an embodiment of the present invention.

Fig. 2 is a flowchart showing an outline of the operation of the control device.

Fig. 3 (a) and (b) show a lower plate and an upright plate as members to be welded, that is, welded, (a) is a perspective view of the lower plate, and (b) is a perspective view of a state in which the upright plate is attached to the lower plate.

Fig. 4 (a) and (b) are diagrams illustrating the concept of a process of extracting two intra-image vertices from a member to be welded, (a) illustrates a process of extracting intra-image vertices from a lower plate as a member to be welded, and (b) illustrates a process of extracting intra-image vertices from a plurality of lower plates joined.

Fig. 5 (a) to (d) show examples of a method for extracting an intra-image vertex, and (a) to (c) show examples of a method for extracting two intra-image vertices, and (d) shows an example of a method for selecting one vertex when extracting two intra-image vertices.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, a welding robot system to which the present invention is applied will be described

As shown in fig. 1, the welding robot system 100 includes a welding robot 1 and a computer as a control device 15, and the control device 15 includes a robot teach pendant 17 used as a teach pendant, for example.

The welding robot 1 is, for example, a double welding robot device having two welding torches. The welding robot 1 has a support frame 2. The support frame 2 includes: four struts 2 a; a pair of guide support beams 2b bridged between the tops of the widely spaced struts 2a among the four struts 2 a; and a pair of frames 2c bridged between the tops of the narrowly spaced struts 2 a. The base end side of the plate-like guide support member 3 projecting in the direction of the opposed guide support beam 2b is fixed to the lower surface of the

guide support beams

2b, 2b of the support frame 2. Further, a linear guide section 4, which is composed of a linear guide and a linear guide support section guided by the linear guide so as to be able to reciprocate, is fixed to the upper surfaces of the guide support members 3 so as to be parallel to the guide support beams 2 b.

The traveling bogie 5 having a structure described later is configured to be capable of reciprocating by the linear guide support portions of the linear guide portions 4. That is, the traveling bogie 5 is configured such that a mounting bracket 5a whose base end side is fixed to the upper surface of the table frame is attached to the linear guide support portion and reciprocates at a position near the lower end inside the

guide support beams

2b, 2 b. That is, the travelling bogie 5 is configured to reciprocate at a position corresponding to the lower table frame of the travelling bogie of the conventional example.

A θ -axis frame 6 that houses a θ -axis (rotation axis) 6a is attached to a widthwise central position of the travel bogie 5, and a rotation frame 7 that rotates about a center in the longitudinal direction as a rotation center is horizontally attached to a projecting end of the θ -axis 6a projecting from the θ -axis frame 6.

On the lower surface of the distal end portion of the rotating frame 7, 6-axis vertical articulated robots 8 are attached to be rotatable around vertical axes, respectively, and welding torches are attached to the distal ends of the 6-axis vertical articulated robots. Two wire packages 9 containing a coiled welding wire are mounted on the upper surface of the travelling bogie 5. A cable drag chain (registered trademark) 11 for supplying welding power by operating the traveling bogie 5 and the robot 8 is provided on the upper surface 10 of one guide support beam 2b of the pair of guide support beams 2 b.

In the present embodiment, the welding robot 1 is a double welding robot device having two welding torches, but the type of welding robot to which the present invention is applied is not particularly limited.

A member to be welded W to be welded by the welding robot 1 is disposed below the welding robot 1, particularly below the robot hand 8 having a welding torch attached to the tip thereof, and a plurality of members to be welded W are welded by the welding torch of the robot hand 8. The member to be welded W is a variety of metal members, and includes a lower plate 21, an upright plate 22, and the like (see fig. 3) described later.

The welding robot 1 of the embodiment further includes a camera 12 as a sensor for imaging the member to be welded W. The camera 12 captures an image of the welded member W that is actually placed, and acquires an image of the welded member W. The type of the sensor is not particularly limited, and the mounting position of the sensor is not particularly limited, as long as the member to be welded W can be imaged.

The control device 15 acquires bead information relating to construction conditions of a bead for welding two members to be welded, which are objects to be welded. The control device 15 is a computer that executes the method of acquiring the welding bead information in accordance with a predetermined program and outputs an operation instruction for the welding robot 1, that is, an acquired welding bead in accordance with a program (teaching program) taught in advance, thereby controlling the operation of the welding robot 1. The control device 15 includes a control unit 16 including a processor that reads and executes a program, a memory that stores other data, and a storage device such as a hard disk. In particular, the control device 15 stores a database of three-dimensional CAD data as design data of the workpiece W, and refers to the three-dimensional CAD data when controlling the operation of the welding robot 1. The database of the three-dimensional CAD data may be constructed by a server or the like connected to the control device 15 via a network, and the location, form, and the like of the database are not particularly limited.

Fig. 2 is a flowchart showing an outline of the operation of the control device 15. The controller 16 of the control device 15 reads the three-dimensional CAD data from a storage device (not shown) by an operation of the operator of the welding robot system 100 (step S1). Here, three-dimensional CAD data of the member to be welded W to be welded is read. Then, the control unit 16 acquires a weld bead, which is a trajectory of a welding portion where the plurality of members to be welded W are welded, from the three-dimensional CAD data (step S2). Further, as will be described later, the control unit 16 acquires the coordinates of the workpiece W from the image of the workpiece W captured by the camera 12, compares the coordinates with the coordinates in the original three-dimensional CAD data of the workpiece W, and corrects an operation program for controlling the operation of the welding robot 1 based on the difference between the acquired coordinates and the coordinates (step S3). Finally, the control unit 16 outputs a welding information file in which the final operation of the welding robot 1 is recorded (step S4). The welding robot 1 operates according to the welding information file.

In the weld bead acquisition of step S2, the control unit 16 extracts a weld bead for welding the two members to be welded W from the three-dimensional CAD data, as shown in fig. 2. The member to be welded W includes, for example, a lower plate 21 horizontally arranged as shown in fig. 3 (a), and a standing plate 22 (see fig. 3 (b)) having one plate thickness surface (surface corresponding to the thickness of the plate) 22a welded to a main surface (maximum surface) 21a of the lower plate 21. As indicated by the broken line, a weld bead E, which is a weld bead for welding the lower plate 21 and the upright plate 22, is a joint portion where the main surface of the lower plate 21 and the plate thickness surface of the upright plate 22 are joined.

However, the operation program of the welding robot 1 read and executed by the control device 15 is determined on the premise that the member to be welded W to be welded is positioned at a predetermined position, and coordinates corresponding to the position are set in advance. However, in an actual welding operation, the position of the member to be welded W is not necessarily arranged at a predetermined position assumed in advance, and when such a member to be welded W is arranged at a position deviated from the predetermined position, it is difficult to grasp the position of the weld bead E accurately, and there is a possibility that the welding operation may be failed.

Thus, in the present invention, the operation program correction for correcting the operation program of the welding robot 1 is performed in step S3 of fig. 2. That is, the present invention aims to acquire the position of the member to be welded W positioned and arranged by the actual welding robot 1, and to correct the operation program according to the position, thereby performing an appropriate welding operation.

First, the control unit 16 extracts data of a predetermined member to be welded W from the three-dimensional CAD data. Further, the controller 16 acquires a plurality of surfaces from the extracted data of the member to be welded W. As shown in fig. 4 (a), for example, when the member W to be welded is the lower plate 21, the control unit 16 can acquire at least two surfaces corresponding to the main surface 21a and the plate thickness surface 21b of the lower plate 21.

Further, the control unit 16 acquires the largest surface having the largest area among the acquired plurality of surfaces. In fig. 4 (a), the area of the main surface 21a is larger than the plate thickness surface 21b, and this surface is the largest surface.

Further, the control unit 16 extracts at least two vertices on the maximum surface. In fig. 4 (a), two vertexes X1, X2 on the maximum plane of the main surface 21a are extracted.

Then, as shown in fig. 1, the camera 12 as a sensor photographs the member to be welded W positioned and arranged by the welding robot 1. Then, the control unit 16 extracts two intra-image vertices corresponding to the two vertices extracted from the three-dimensional CAD data before from the captured image data of the welding target member W. Here, the control unit 16 can acquire the real coordinates of the welded member W captured at the same time as acquiring the image of the welded member W.

Then, the controller 16 obtains the difference between the coordinates of the two vertices X1 and X2 and the coordinates of the vertices in the two images. Although the inner vertices of the image have actual coordinates of the member to be welded W, X1 and X2 are merely coordinates set in advance in the three-dimensional CAD data, and do not necessarily match each other. Note that the difference Δ between the two coordinates may include, for example, a horizontal difference for moving the member to be welded W without rotating within a specific plane, an angular difference for rotating the member to be welded W, or the like, and the control unit 16 may acquire such various values.

The control unit 16 corrects an operation program for operating the welding robot 1 based on the difference value obtained in the above-described manner. Specifically, the correction can be performed by moving the coordinates of the position of the member to be welded W in the three-dimensional CAD data in accordance with the obtained difference Δ.

Fig. 4 (b) shows an example in which a plurality of members to be welded are divided into one surface, and the one surface is the largest surface. In this case, three

lower plates

211, 212, 213 may be joined together to be regarded as one welded member, and the inner vertices X1, X2 in the image may be extracted from the maximum plane image of the main surfaces thereof.

Fig. 5 (a) shows an example of a method for extracting two vertices X1 and X2. As shown in the drawing, when the tangents L1 and L2 are discontinuous (the directions of the tangents vary greatly) at the vertex X1 in the image of the member to be welded W, the controller 16 can extract the vertex X1. Similarly, at the point X2, the tangents L3 and L4 are not continuous, and therefore the controller 16 can extract the vertex X2. However, in an actual process, the control unit 16 extracts a plurality of candidate points including vertices other than the vertices X1 and X2, determines the continuity of the tangent line with respect to each candidate point, and then determines two appropriate vertices (in this example, X1 and X2 in which the tangent line is discontinuous). In the following example, similarly in (b) to (d) of fig. 5, the control unit extracts a plurality of candidate points in advance and then extracts an appropriate vertex.

Fig. 5 (b) shows another example of the method for extracting two vertices X1 and X2. As shown in the drawing, when the distance D between the two vertexes X1, X2 of the member W to be welded is equal to or greater than the predetermined threshold value T, the controller 16 can extract the two vertexes X1, X2. By using two vertices separated by a predetermined distance threshold or more, more accurate correction can be performed.

Fig. 5 (c) shows another example of the method for extracting two vertices X1 and X2. As shown in the figure, two vectors V1 and V2 may be obtained as vectors connecting two vertexes of one member to be welded W. In this case, the control unit 16 extracts two vertexes of a vector having a combination of the smallest in the short-dimension direction and the largest in the long-dimension direction. By using such a vector, more accurate correction can be performed. In this example, since the vector V1 satisfies this requirement, both ends of the vector V1 are extracted as vertices X1 and X2.

Fig. 5 (d) shows an example of a method for selecting at least one vertex from among the two vertices X1 and X2. As shown in this figure, the apex of the member to be welded W in which no other member exists within the range of the predetermined distance R can be extracted. This is because the vertices of the periphery where no other member exists facilitate coordinate recognition.

The welding robot 1 performs predetermined structure assembly by using the operation program corrected by the operation program correction method. Further, the control device 15 can easily correct the operation program by executing the operation program correction program for causing the computer to execute the operation program correction method.

The welding robot system 100 of the embodiment includes the welding robot 1 and a computer as the control device 15. The computer as the control device 15 teaches a predetermined operation to the welding robot 1. Here, the control device 15 as a computer extracts data of a predetermined member to be welded W from the three-dimensional CAD data, acquires a plurality of surfaces from the extracted data of the member to be welded W, acquires a maximum surface having a maximum area among the plurality of surfaces, extracts at least two vertexes X1, X2 on the maximum surface, the camera (sensor) 12 images the member to be welded W positioned by the welding robot 1, extracts two intra-image vertexes corresponding to the two vertexes from the image data of the member to be welded W imaged, acquires differences between coordinates of the two vertexes X1, X2 and coordinates of the intra-image vertexes, and corrects the operation program based on the differences. The welding robot 1 operates in accordance with the operation program appropriately corrected in accordance with the actual arrangement position of the member to be welded W, and therefore, an appropriate welding operation can be ensured.

The present invention has been described above using the embodiments, but the technical scope of the present invention is not limited to the above embodiments. It will be apparent to those skilled in the art that various changes and substitutions can be made without departing from the spirit and scope of the invention.

The present application is based on the japanese patent application laid-open at 21/3/2017, the content of which is hereby incorporated by reference.

Description of reference numerals:

1 welding robot

12 Camera (sensor)

15 control device (computer)

16 control part

17 robot demonstrator

21 lower plate (welded component)

22 vertical board (welded component)

100 welding robot system

W are welded members.

Claims

1. An operation program correction method for correcting an operation program of a welding robot for welding a member to be welded,

the action program correction method includes:

extracting data of a predetermined member to be welded from the three-dimensional CAD data;

a step of acquiring a plurality of surfaces from the extracted data of the members to be welded;

a step of acquiring a maximum face having a maximum area among the plurality of faces;

a step of extracting at least two vertices on the maximum surface;

a step in which a sensor images the member to be welded positioned and arranged by a welding robot;

extracting two intra-image vertexes corresponding to the two vertexes from the captured image data of the member to be welded;

a step of obtaining a difference value between the coordinates of the two vertexes and the coordinates of the vertexes in the two images; and

and correcting an operation program for operating the welding robot based on the difference.

2. The action program correcting method according to claim 1,

in the step of extracting the two vertices, when the distance between the two specified vertices is equal to or greater than a predetermined threshold, the two vertices are extracted as intra-image vertices.

3. The action program correcting method according to claim 1,

in the step of extracting the two vertices, at least one vertex from which data of the welded member is not present for another member within a range of a predetermined distance is extracted.

4. A method of assembling a structure, characterized in that,

the action program correction method according to any one of claims 1 to 3.

5. A medium, characterized in that,

the medium has an operation program correction program for causing a computer to execute the operation program correction method according to any one of claims 1 to 3.

6. A welding robotic system, comprising:

a welding robot that welds a member to be welded; and

a computer for controlling the operation of the welding robot according to a predetermined operation program,

it is characterized in that the preparation method is characterized in that,

the computer executes the following processing:

extracting data of a prescribed welded member from the three-dimensional CAD data,

obtaining a plurality of surfaces from the extracted data of the members to be welded,

obtaining a largest face having a largest area among the plurality of faces,

extracting at least two vertices on the largest face,

acquiring an image of the member to be welded positioned and arranged by the welding robot captured by a sensor,

extracting two intra-image vertexes corresponding to the two vertexes from the captured image data of the members to be welded,

obtaining the difference between the coordinates of the two vertices and the coordinates of the vertices within the two images,

correcting the motion program based on the difference value.