JPH11347733A - Automatic teaching method for welding robot and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve working efficiency of an automatic teaching method for a welding robot and its device. SOLUTION: At the time of preparing a design data A drawn in three dimensions with a CAD system 11, when an attribute code on whether welding is executed or not to each joint part is embedded into the design data A with a welding procedure automatic deciding system 12, the information of an opposite surface corresponding to a surface to be welded is stored in the attribute data, and when welding is instructed to a certain surface based on the attribute data, a mating surface is obtained from the attribute data, a joining line is geometrically obtained from two surfaces thereof, and the joining line is obtained as a weld line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention automatically determines a welding line and a welding position of a welding robot on the basis of a three-dimensional CAD shape, and forms a box shape (construction machine, automobile, machine tool, other welding machine, etc.). The present invention relates to an automatic teaching method and apparatus for a welding robot that determines a welding order of a welding robot having a positioner with a member having a structural member according to the specification of the positioner.

[0002]

2. Description of the Related Art In conventional welding, a welding sequence is set by utilizing the experience of an operator, a welding position and welding conditions are taught to a controller in the order, and welding is performed by this welding robot. In the conventional teaching of a welding robot, offline teaching is performed, that is, teaching is performed in advance on a desk in an office or the like, and the teaching data is stored in the robot using an external storage device such as a communication line or a floppy disk. By making welding and teaching work in parallel, the operating rate of this welding robot is increased. That is, since the teaching is not performed on the machine, the welding can be performed during that time, so that the operating rate of the welding robot can be increased.

[0003]

However, in the conventional welding, the operator teaches the welding position and welding conditions to the robot controller in the order of welding, so that labor cannot be saved. However, there is a problem that workability is not good. Further, since the teaching of the conventional robot is off-line teaching, it is necessary for a person in the office to teach instead of the worker, and the teaching operation cannot be performed efficiently.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a method and an apparatus for automatically teaching a welding robot which improve the working efficiency.

[0005]

According to a first aspect of the present invention, there is provided an automatic teaching method of a welding robot for achieving the above object.
When the CAD system creates design data drawn in three dimensions, if an attribute code indicating whether or not to weld each joint is embedded in the design data, the attribute code corresponds to the surface to be welded. The information of the opposite side is stored in the attribute data,
When a welding instruction is given on a certain surface based on the attribute data, a mating surface is determined from the attribute data, a joining line is geometrically determined from the two surfaces, and the joining line is determined as a welding line. It is characterized by having done.

In the automatic teaching method for a welding robot according to the second aspect of the present invention, a starting point and an ending point of the welding line are obtained, and a normal vector on one side of the welding start and end points and a normal vector on the other side are obtained. A vector that equally divides this is determined as each release direction vector, obtained for all the welding lines of the joints, and this release direction vector or an angle from one side is designated and used as a welding posture, thereby obtaining this. It is characterized in that all joints are defined in the same way, and the release direction of the member into which the welding torch can enter is obtained from the shape of the design data.

In the automatic teaching method for a welding robot according to the third aspect of the present invention, when a work positioner is provided, downward welding can be performed as much as possible from the release direction vector in accordance with the unit of the index angle of the peripheral device. Preferably, a welding line is automatically set for each rotation index angle of the positioner.

In the automatic teaching method for a welding robot according to a fourth aspect of the present invention, a welding line is selected within a stroke range according to the arrangement of the welding robot, and the welding line is selected for a plurality of opposing robots. It is characterized in that automatic territory division is automatically determined from the direction of the release direction vector so that welding can be performed in an optimum posture.

In the automatic teaching method for a welding robot according to a fifth aspect of the present invention, a release direction vector and a plate thickness at the welding start and end thereof are obtained, and welding is performed with the thicker plate facing downward. It is characterized by:

In the automatic teaching method for a welding robot according to the present invention, it is determined which index angle is to be used in order from the welding line length for each index angle. It is characterized in that the index order is determined so that distortion is minimized by welding.

According to a seventh aspect of the present invention, there is provided an automatic teaching device for a welding robot, wherein a three-dimensional CA for creating three-dimensional design data is provided.
D system, a welding procedure automatic determination system for outputting welding line data, welding position data, and welding procedure instruction data based on the three-dimensional setting data, and using the welding line data, welding attitude data, and welding procedure instruction data. An automatic offline determination system for performing automatic teaching and outputting teaching data is provided.

[0012]

FIG. 1 is a flowchart showing a system of an automatic teaching method by an automatic teaching device of a welding robot according to an embodiment of the present invention. FIG. 2 is an explanatory view showing a welding line and a release direction vector of a member. 3 shows an explanation for obtaining a release direction vector from a normal vector of each surface of a welding portion, FIG. 4 shows an example of a release direction vector of a block-shaped member, and FIG. 5 shows a welding line using a 90-degree index positioner. FIG. 6 shows a description showing the result of selecting the welding line by using a 45-degree index positioner.

As shown in FIG. 1, an automatic teaching device for a welding robot according to this embodiment includes a three-dimensional CAD system 11 for creating three-dimensional design data A, and three-dimensional setting data A
Procedure 1 for outputting welding line data B, welding attitude data C and welding procedure instruction data D based on the
The welding posture data C can be corrected using the peripheral equipment condition database E. Further, the automatic teaching system 13 has an offline automatic determination system 13, and can automatically output teaching data F by using welding line data B, welding posture data C, and welding procedure instruction data D.

That is, the three-dimensional CAD system 11 creates design data A (surface or solid shape data) drawn in three dimensions. At this time, the design data A includes whether or not welding is to be performed on each joint, and if so, as shown in FIG. 2, the surface SA on the member 22 adjacent to the welding line 21 to be welded. And the attribute of welding to the surface SB on the member 23 are stored. In other words, the “surface SB” is added to the surface SA so that it can be determined which surface is to be welded.
Is stored in the attribute data. Also, the code (1) for welding is stored in the attribute data, and similarly,
A code (2) indicating that the surface SB is to be welded to the surface SA.
Is stored in the attribute data. On the other hand, when welding is not performed, the code (0) is stored as an attribute. This can be realized, for example, by customizing a commercially available CAD system (the user creates a program in C language or the like, incorporates the program into the commercially available CAD system, and instructs the operator). At that time, if the leg length or groove shape is specified, it is embedded as attribute data,
In some cases, the welding conditions at the welding location are embedded.

[0015] A specific CAD operator's instruction method is, for example, by clicking an instruction box of a welding line,
Click the surface SA with the message "Please specify the first surface to be the welding line."
Please indicate the side of. SB with the message "
Is clicked to store “Surface SB” and “Welding code” as attributes of surface SA and “Surface SB” and “Welding code” as attributes of surface SB according to these two designated surfaces. .

The welding procedure automatic determination system 12 checks whether or not there is a welding instruction in the attribute data for each surface based on the above-described three-dimensional design data A. That is, in the above-described example, the processing is performed when either (1) or (2) is performed. In (1) and (2), either one may be processed. When a welding instruction is given, for example, when a welding instruction is given on the surface SA, a mating surface SB is obtained from the attribute data, and a joining line is geometrically obtained from the two surfaces. Is obtained as the welding line 21. Further, the starting point PA and the ending point PB of the welding line 21 are also determined (which starting point or the ending point may be determined arbitrarily in order to automatically determine the procedure later), and is used for all the joints. Define similarly.

Next, the release direction vectors VA, VB of the members
The release direction in which the welding torch can enter with respect to the position is determined from the shape of the design data A. That is, as shown in FIG. 3, a vector that equally divides the normal vector V1 of the surface SA and the normal vector V2 of the surface SB at the welding start point PA is obtained and set as a release direction vector VA. Similarly, the release direction vector VB on the end point side is obtained, and this is obtained for the welding lines 21 of all joints.

Next, an example in which a work positioner is provided will be described. The presence or absence of a positioner is checked according to FIG. If there is a positioner, check whether the positioner is a device that can rotate freely. The positioner capable of rotating freely determines whether to skip the following processing based on the setting of the database in the computer or the instruction of the operator. For example, when welding the four sides of a hexahedral box-shaped member having a box shape as shown in FIG. 4 excluding the front and rear, there is a possibility that the welding posture is at an arbitrary angle from the viewpoint of efficiency. When welding while positioning in that direction, it takes longer than welding at a certain angle at once,
For box-shaped members, generally 45 degrees or
A method is adopted in which the surface is indexed at 90 degrees and the surfaces are welded together. Hereinafter, the logic for doing so will be described. In the case of a positioner that cannot rotate freely (generally called an index table), or in the case of performing welding at several angles (every 45 degrees or 90 degrees) as described above, the following processing is performed. This is because it is impossible to set the welding position in such a way on the rotary table in terms of hardware. Therefore, the following processing is required.

As shown in FIG. 4, if the positioner rotates on the XY plane depending on which plane the azimuth of the center of the rotation axis rotates, the release direction vector V is set with respect to the vector on the XY plane in that direction. Is rounded (rounded to the specified angle), and the rotation position to be welded is determined. For example, for a 90-degree index, 0, 9
Since there are four positions of 0, 180, and 270 degrees, a release direction vector V of 45 to 135 degrees is selected when rotated to this angle. At this time, in the example shown in FIG.
A11, VA12, VA22, and VA41 are targets.
Next, it is determined which welding line can be formed according to the specifications of the welding robot.

That is, assuming that one robot is placed in the plus direction of the X-axis, VA41 and VA12 are obtained from the stroke relationship. Conversely, if it is placed in the minus direction of the X axis, VA22 and VA11 are selected.

A robot having an external axis, such as a gantry with a moving axis in the X-axis direction, in which the robot is suspended from the ceiling, can be welded for all four objects.

When two robots are arranged so as to face left and right, it is necessary to determine which robot is to be used for which welding line with respect to the two robots. In this case, as described above, the robot placed in the plus direction of the X-axis is VA41 and VA12, and the robot placed in the minus direction of the X-axis is VA22 and VA12.
Select 11.

In the case of a ceiling-suspended robot or a two-sided robot, the four welding lines can be welded at different angles. Ask. That is, VA11 and V
A22 is 0 degrees and 270 degrees, VA12 and VA41 are 0 degrees.
Welding is possible at any of the degrees and 90 degrees. Therefore, considering the followability and distortion of the arc sensor (a sensor that weaves the welding torch and detects a change in welding current at that time and follows the welding line), it is better to weld with the thicker plate down. In consideration of the good point, the plate thickness at the start and end points of each welding line is determined in the direction opposite to the normal vector. That is, for the release direction vectors VAi and VBi, the surface SA
The plate thickness t1i of the side and the plate thickness t2i of the surface SB (two plate thicknesses are obtained at the start point and the end point, but are determined as an average value), and the plate thicknesses are compared and selected so that the thicker one is lower. . In FIG.
For VA11 and VA12, t11 and t12 are compared. Similarly, in VA22, t21 and t2
2. In VA41, t41 and t42 are compared and selected. As a result, when the welding line is selected such that the thicker plate is set downward, the welding line can be selected for each angle as shown in FIG.

Similarly, in the case of a 45-degree index, rounding is performed so as to output in 45-degree units.
Normally, as shown in FIG. 4, in a box-shaped member, the welding posture (release direction vector V) is in a 45-degree direction, and therefore, as shown in FIG. 6, the welding is all downward. In this example, the output is in units of 45, 135, 225, and 315 degrees. However, actually, the output is performed at a 45-degree pitch, so that 0, 45, 90, 135, 180, 225, and 27 are output.
A welding line will be selected every 0,315 degrees.

The number of roundings can be calculated by inputting the unit index amount into the peripheral device condition database E.

The welding target is determined at each index, and the order in which each index is performed is also determined.
In this case, welding is performed from a portion having many joints from the viewpoint of minimizing distortion. That is, the welding line length is determined for each surface,
Welding is performed in the order of the index angle with the largest amount.

Next, the welding order for each surface is determined (when there are a plurality of welding robots, the welding order is determined for each welding robot and each surface). There are several general methods for obtaining the welding order in one plane, and any one of these methods may be used. For example, Nearest Neighbor
Method, Greedy method, Farthest Insertion method, Christofides A
lgorithm method, etc.
There are an OPT method, a 3-OPT method, a Lin-Kernigham method and the like. In this case, the start point and the end point of the welding are formed into a logic with a rule that the processing is performed in two pairs. The starting point and the ending point of the welding are tentatively determined. However, the setting is changed in the order described above in a welding procedure in which the total blank feeding distance is shortened.

As described above, the welding order is obtained for each welding robot and for each index angle (indexes are output in the order of the welding line length for each index, and as shown in FIG. 1). , Teaching data F
Is output. Therefore, the welding is performed by storing the teaching data F in the welding robot and executing it.

[0029]

As described above in detail in the embodiment, according to the automatic teaching method of the welding robot according to the first aspect of the present invention, when the CAD system creates the design data drawn in three dimensions, When embedding an attribute code indicating whether or not to perform welding on each joint in the design data, information on the opposite surface corresponding to the surface to be welded is stored in the attribute data, and the design is based on this attribute data. When there is a welding instruction on the surface, the other surface is obtained from the attribute data.
Since the joining line is geometrically determined from the three surfaces and the joining line is determined as the welding line, the working efficiency of the welding operation can be improved.

In the automatic teaching method for a welding robot according to the second aspect of the present invention, the starting point and the ending point of the welding line are obtained, and the starting point and the ending point of the welding line are calculated from the normal vector on one side and the normal vector on the other side. Vectors to be equally divided are determined as each release direction vector, and the welding direction of all joints is determined.This release direction vector or the angle from one side is designated and used as the welding posture, and this is used for all welding positions. Since the release direction of the member into which the welding torch can enter is determined in the same manner as the joint, based on the shape of the design data, the welding line can be determined with high accuracy.

In the automatic teaching method for a welding robot according to the third aspect of the present invention, when a work positioner is provided, downward welding can be performed as much as possible from the release direction vector in accordance with the unit of the index angle of the peripheral device. Since the welding line is automatically set for each rotation index angle of the positioner, the welding line can be easily obtained.

In the automatic teaching method for a welding robot according to a fourth aspect of the present invention, a welding line is selected within a stroke range according to the arrangement of the welding robot, and the welding line is selected for a plurality of opposing robots. Since the automatic territory division is automatically determined from the azimuth of the release direction vector so that welding can be performed in an optimum posture, high-quality welding can be performed.

In the automatic teaching method for a welding robot according to the fifth aspect of the present invention, a release direction vector and a plate thickness at the welding start and end thereof are obtained, and welding is performed with the thicker plate facing downward. Therefore, high quality welding can be performed.

In the automatic teaching method for a welding robot according to the sixth aspect of the present invention, the welding line length for each index angle is determined from the index angle, and the welding line length for each index angle is determined in order from the surface having the longer length. Since the index order was determined so that distortion was minimized by performing welding,
The welding procedure can be easily determined.

According to a seventh aspect of the present invention, there is provided an automatic teaching device for a welding robot, comprising: a three-dimensional CA for creating three-dimensional design data;
D system, automatic welding procedure determination system that outputs welding line data, welding attitude data, and welding procedure instruction data based on three-dimensional setting data, and automatic teaching using welding line data, welding attitude data, and welding procedure instruction data And an offline automatic determination system that outputs teaching data, thereby improving the work efficiency of the welding work with a simple device.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a system of an automatic teaching method by an automatic teaching device of a welding robot according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a welding line and a release direction vector of a member.

FIG. 3 is an explanatory diagram for obtaining a release direction vector from a normal vector of each surface of a welding location.

FIG. 4 is an explanatory diagram showing an example of a release direction vector of a member having a block shape.

FIG. 5 is an explanatory diagram showing a result of selecting a welding line with a positioner having a 90-degree index.

FIG. 6 is an explanatory diagram showing a result of selecting a welding line with a 45-degree index positioner.

[Explanation of symbols]

 11 3D CAD system 12 Automatic welding procedure determination system 13 Offline automatic determination system A 3D design data B Welding line data C Welding posture data D Welding procedure instruction data E Peripheral equipment condition database F Teaching data

Continued on the front page (72) Inventor, Aki Matsuda, 3000 Tana, Sagamihara-shi, Kanagawa Prefecture, Mitsubishi Heavy Industries, Ltd., Sagamihara Manufacturing Co., Ltd.

Claims (7)

[Claims] 1. When design data drawn in three dimensions is created by a CAD system, when an attribute code indicating whether or not to perform welding on each joint portion is embedded in the design data,
Information of the opposite surface corresponding to the surface to be welded is stored in the attribute data, and when there is a welding instruction on a certain surface based on this attribute data, a partner surface is obtained from the attribute data,
An automatic teaching method for a welding robot, wherein a joining line is geometrically determined from these two surfaces, and the joining line is determined as a welding line. 2. The automatic teaching method for a welding robot according to claim 1, wherein a starting point and an ending point of the welding line are obtained, and welding is started.
From the normal vector of one surface on the end point side and the normal vector of the other surface, a vector that equally divides this is determined as each release direction vector, and it is determined for all the welding lines of the joints. By designating the angle from one side and using it as the welding posture, this is defined in the same way for all joints, and the release direction of the member into which the welding torch can enter can be obtained from the shape of the design data. Automatic teaching method of welding robot. 3. The method for automatically teaching a welding robot according to claim 1, wherein when a work positioner is provided, downward welding can be performed as much as possible from a release direction vector in accordance with a unit of an index angle of a peripheral device. An automatic teaching method for a welding robot, wherein a welding line is automatically set for each rotation index angle of the positioner. 4. The automatic teaching method for a welding robot according to claim 3, wherein a welding line is selected within a stroke range in accordance with the arrangement of the welding robot, and the welding line is automatically territoryd even for a plurality of opposed robots. An automatic teaching method for a welding robot, wherein the division is automatically determined from the direction of a release direction vector so that welding can be performed in an optimum posture. 5. The automatic teaching method for a welding robot according to claim 3, wherein a release direction vector and a plate thickness at the welding start and end thereof are obtained, and welding is performed with the thicker plate facing downward. A featured automatic teaching method for welding robots. 6. The method for automatically teaching a welding robot according to claim 1, wherein the welding line length for each index angle is determined from which of the index angles to perform the welding in order, and welding is performed in order from the surface having the longer length. An automatic teaching method for a welding robot, wherein an index order is determined so that distortion is minimized. 7. A three-dimensional CA for creating three-dimensional design data
D system, a welding procedure automatic determination system for outputting welding line data, welding position data, and welding procedure instruction data based on the three-dimensional setting data, and using the welding line data, welding attitude data, and welding procedure instruction data. An automatic teaching device for a welding robot, comprising: an automatic off-line determination system for performing automatic teaching and outputting teaching data.