JP2836281B2 - Data creation method for welding robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data creation method for a welding robot, and more particularly to a technique for shortening data creation time and improving data creation accuracy.

[0002]

2. Description of the Related Art As one of welding robots, there has been known a welding robot which moves a torch held by the robot along a welding line on a workpiece to perform welding. This type of welding robot stores the positions of a plurality of teaching points set on a welding line to be followed by a torch and the angle of the torch set at each of the teaching points sequentially after being stored along the welding line. Based on the teaching point information, the torch is made to follow a welding line that is a straight line, a broken line, or a curve according to a PTP (point to point) control method.

[0003] In the field of welding robots, for example, the literature "Revision 3 Welding Handbook (September 20, 1982)"
As described on pages 265 to 266 of Maruzen Co., Ltd.), prior to welding, a human manually makes a torch follow a predetermined welding line by a manual operation to teach an operation to be performed by a welding robot. That was being done. Specifically, the torch is sequentially moved to each of a plurality of teaching points assumed on the welding line, and at each teaching point, the torch is moved forward and backward from a reference line extending vertically from each teaching point on the surface of the workpiece to be welded ( The welding robot was taught by giving a traveling angle and a target angle, which are angles inclined in the left-right direction and the traveling direction of the welding line, respectively.

[0004]

However, it is troublesome and time-consuming to manually teach the operation to be performed by the welding robot by a manual operation, and the traveling angle and the aiming angle of the torch are sufficiently set. Has a problem that teaching cannot be performed with high accuracy. The present invention has been made to solve this problem.

[0005]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides a welding robot in which a torch is placed on a workpiece.
Data required to move along the defined weld line
It is a method of making by computer, and (a)
A wire that approximates the surface of an object with multiple wires
Workpiece surface display displayed on the screen as a frame model
Process, and (b) on the screen based on the operation of the operator
Of the surface elements defined by the wires,
A surface element designating process for designating an object including a tangent line, and (c) an operation
Based on the operation of the
Teach points on the number of outlines that match the welding line
Specifying the teaching point designation process and (d)
By doing the same, multiple outlines of the specified surface element
Outer line selection process to select the one that matches the welding line
And (e) the specified surface element based on the operation of the operator
About when the torch is moved along the weld line
The torch moves forward and backward from a reference line extending vertically from the teaching point
And the relative travel, which is the angle of inclination in each of the left and right directions
Relative advancing angle and relative aiming angle to input angle and relative aiming angle
Input process, (f) specified surface element and specified teaching
The point, the selected outline, and the entered relative travel angle and
Of the teaching point, based on the
The absolute coordinates in the coordinate system set as
The point data and the relative travel angle and
Absolute progression in the coordinate system when tilting at a relative aim angle
Create direction data that defines the angle and absolute aim angle
And a data creation step.

The input of the relative advancing angle and the relative aiming angle is performed, for example, only once for a plurality of teaching points of the workpiece.
The operation can be performed such that a common value is set for those teaching points, or the operation can be performed for each teaching point. In the latter case, the input of the torch relative angle for each teaching point is first input as to whether or not the value is the same as the previous value. The input can be omitted, and if not the same, the current value can be input.

[0007]

In the method for creating data for a welding robot according to the present invention, the surface of the workpiece is formed by a plurality of wires.
Using a wireframe model that is approximately represented
From the weld line and teach on the weld line
A point is specified. Specifically, (i) the surface of the workpiece is
Wireframe model that approximates the surface with multiple wires
(Ii) based on the operation of the operator.
Multiple, defined by multiple wires on the screen
Of the surface elements that include the weld line are specified, and (iii)
Specify the specified surface element based on the operation of the perlator
Teach points on the multiple outlines that match the weld line
(Iv) by cooperating with the specified teaching point.
Of one or more outlines of the specified surface element
The one that matches is selected. Furthermore, this data creation method
In, the wireframe model and the operator
Based on the information, set the teaching point for the entire workpiece
Data that specifies the absolute coordinates in the specified coordinate system
And the torch moves at the teaching point
Absolute tilt angle in the coordinate system when tilting at an angle and
Direction data defining an absolute aim angle is created. Concrete
Specifically, (i) the designated surface is specified based on the operation of the operator.
For the element, the torch is moved along the weld line
When the torch moves back and forth from a reference line extending vertically from the teaching point
Relative angle, which is the angle of inclination in the left and right directions
The advancing angle and the relative aiming angle are input, and (ii) the designated surface
The element, specified teaching point, selected outline,
Teaching based on the applied relative advance angle and relative aim angle
Point data that defines the absolute coordinates of the point and the teaching point of the torch
Direction data that defines the absolute travel angle and the absolute aim angle
Is created.

[0008]

As described above, according to the present invention, data for a welding robot is created without manually moving the torch along the welding line, thereby reducing the time required for teaching the welding robot. The effect that it can be obtained is obtained. Also, a wire that approximately represents the surface of the workpiece
Since the torch point data and the direction data are created based on the ear frame model , the effect of improving the teaching accuracy of the welding robot and thus the welding quality can be obtained.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a method for preparing data for a welding robot according to an embodiment of the present invention.

FIG. 2 shows a welding data creating apparatus using the present data creating method. As illustrated, the welding data creation device includes a computer 10. Computer 1
Numeral 0 mainly includes a CPU 12, a ROM 14, and a RAM 16. The computer 10 is connected with an auxiliary memory 20, input means 22, and display means 24. The auxiliary memory 20 stores wireframe data defining a wireframe model in which the surface of the workpiece is approximated by a plurality of wires (linear elements) . The input unit 22 includes a keyboard, a mouse, and the like, and the display unit 24 includes a CRT and the like.
The ROM 14 stores various programs including the welding data creation program shown in the flowchart of FIG.

The operation of the welding data creation device will be described.
As shown in FIG. 3, two members 40 and 42, which together form a container, are fitted to each other, and the inner edge of the cylindrical end surface of the outer member 40 and the above-described edge of the outer surface of the inner member 42. An example in which continuous fillet welding is performed on a portion in contact with a portion will be described.

When the power is turned on, the CPU 12 performs a predetermined initial setting and then executes the welding data creation program shown in FIG. First, in step S1 (hereinafter simply referred to as S1; the same applies to other steps), wireframe data is read from the auxiliary memory 20 into the RAM 16, and based on this, the wireframe model of the workpiece is displayed on the screen of the display means 24. Displayed above. For example, the part circled in FIG. 3 is displayed as shown in FIG. On the basis of the display result, the operator operates the input means 22 to specify a specific surface element desired to create a point and a direction (hereinafter collectively referred to as “taught point information”) relating to the torch this time from a plurality of wires. A first guide line and a second guide line for defining are selected. Two wires facing each other are selected from the four wires defining the specific surface element. 4, it is assumed that the first guide line 50 and the second guide line 52 are selected, and the plane element 54 is set as the current specific plane element.

Thereafter, in S2, the teaching point M on the welding line scheduled on the specific surface element is designated according to the operation of the mouse of the input means 22. Data designating the position of the teaching point M using a mouse is input to the computer 10, and this data is one mode of the input data relating to the position of the teaching point in the present invention. In the example of FIG. 4, the first guide line 50 is a welding line. Since the welding line is a straight line, the teaching point M is an end point on the welding start side (in this case, the end point of the first guide line 50). (Assuming the left end point). In this step, the work coordinate system x of the teaching point M set for the workpiece is further set.
The absolute coordinates on -yz are determined, and the point data defining the absolute coordinates are stored in the RAM 16 in association with the welding order.

Subsequently, in S3, a reference point P on the welding line and ahead of the teaching point M is designated according to the operation of the input means 22. In the example of FIG. 4, since the first guide line 50 is a straight welding line, the reference point P is the other end point (right end point) of the first guide line 50. Thereby, in the example of FIG. 7, a straight line extending from the teaching point M toward the reference point P is input to the computer 10 as a welding line of the surface element 54. That is, in the present embodiment, designating the position of the reference point P is designating the direction of the welding line at the teaching point M, and the data designating the position of the reference point P is the direction of the welding line in the present invention. This is one mode of the input data related to. In S4, a vector N extending from the teaching point M toward the reference point P and having a length of 1 (the direction matches the traveling direction of the welding line) is generated.

Thereafter, in S5, the direction in which the torch extends at the teaching point M is changed according to the operation of the input means 22.
Whether the direction is the positive direction or the negative direction of the z-axis of the work coordinate system xyz is input. For the example of FIG. 4, assuming that the torch was scheduled to take the position shown in FIG. 5 by the vector X (the direction corresponds to the direction in which the torch extends) at the teaching point M, the direction of the torch is negative z. It is entered as being in the axial direction. Subsequently, in S6, the normal direction and the reverse direction of the normal line of the specific surface element at the teaching point M are determined based on the wire frame data defining the specific surface element. A vector A is generated which extends in parallel with the smaller angle between the two normal directions and the direction of the torch and has a length of one.

Thereafter, in S7, the relative advance angle θ and the relative aim angle α of the torch are designated according to the operation of the input means 22. As shown in FIG. 5, the relative advancing angle θ is determined by welding the center line of the torch from a reference line S (which is an embodiment of the reference line in the present invention) extending in parallel with the vector A through the teaching point M. Means the angle of inclination in the direction opposite to the direction of travel of the line (the direction opposite to the vector N), while the relative aiming angle α is π / 2, and the center line of the torch is welded from the reference line S To the right of the direction of travel of the line (vector N
(In the direction of the vector O which is the outer product of the vector and the vector A). That is, the relative advancing angle θ is an angle formed by two images projected in parallel to the vector O with respect to a plane (shown by an O-direction projection plane in the drawing) in which the reference line S and the vector X are perpendicular to the vector O. On the other hand, the relative aiming angle α is the vector O and the vector X
Is the angle formed by the two images projected parallel to the vector N with respect to a plane perpendicular to the vector N (shown by an N-direction projection plane in the figure). In short, in the present embodiment, the data specifying the relative advancing angle θ and the relative aiming angle α is one mode of the input data relating to the relative advancing angle and the relative aiming angle in the present invention.

Subsequently, in S8, a vector X 1 whose vector X is parallel to the image projected on the O-direction projection plane and whose length is ₁ is determined. The relationship between the vector X ₁ and the vector A is as follows:
Therefore, the inner product of the vector X ₁ and the vector A = the length (= 1) of the vector X _{1 and} the length (= 1) of the vector A
It is the product of COS θ. Therefore, the vector X ₁ is expressed by using three unit vectors N, A, and O orthogonal to each other, and the relationship expressed by the above equation and the vector X ₁ are O
By utilizing the fact that it is on the directional projection plane and that the vector X ₁ is a unit vector, the characteristics of the vector X ₁ can be determined.

In this step, the vector X
Are parallel to the image projected on the N-direction projection plane, and a vector X ₂ having a length of 1 is determined. The vector X ₂
Since the angle between them and the vector O is (π-relative target angle α), the inner product of the vector X ₂ and the vector O = the length (= 1) of the vector X _{2 and} the length of the vector O (= 1) and COS (π-α). Therefore, the vector X ₂ is similarly expressed using three unit vectors N, A, and O orthogonal to each other,
And, a relation represented by the above formula, and that vector X ₂ are on N direction projection plane, by utilizing the fact vector X ₂ is a unit vector, can determine the characteristics of the vector X _2. In this step, the vectors X ₁
And the sum of X ₂ and X ₂ is defined as a vector X.
Three inclination angles based on each coordinate axis of the workpiece coordinate system xyx are calculated, and direction data defining the inclination angles is stored in the RAM 16 in association with the point data.

Thereafter, in S9, it is determined whether or not other teaching point information should be created at the same torch angle for the current specific surface element. If it is assumed that only one piece of teaching point information is created this time for a specific surface element, the determination is NO in accordance with the operation of the input means 22, and in S10, is teaching data no longer created for the specific surface element? No, that is, whether or not the creation of the teaching point information for the specific surface element has been completed. This time, from the above assumption,
The determination is YES in response to the operation of the input means 22, and S1
In 1, it is determined whether or not the creation of the teaching point information has been completed for the entire workpiece. If there is an input from the input means 22 that the creation is not completed, the determination is NO, and
Returning to S1, the program is executed for a new specific surface element. If there is an input indicating that the creation of the teaching point information has been completed, the determination becomes YES. In this case, in S12, a plurality of point data and direction data are sequentially read from the RAM 16 in accordance with the welding order, and each is converted with respect to the robot coordinate system set for the welding robot. In S13, the converted data is converted. The point data and the direction data are stored in the auxiliary memory 20. This completes one execution of the program.

On the other hand, if it is necessary to create other teaching point information at the same torch angle for the current specific surface element, the determination in S9 becomes YES, and in S14,
According to the operation of the input means 22, the position of at least one other teaching point M is designated, and in S15, the previous relative advancing angle θ and the relative aiming angle α are used, and in the same manner as in the previous case, A vector X is generated for the teaching point M, and thereafter, S11 and the subsequent steps are executed.

As described above, in this embodiment, since the point data and the direction data for the welding robot are created using the wire frame data of the workpiece, the data is created accurately and in a short time. In addition, the time required for teaching the welding robot can be reduced, and the effect of improving the welding quality can be obtained.

In this embodiment, if the present value is the same as the previous value in each torch angle input, the input of the torch angle value is omitted. The effect of shortening the time required for is obtained.

In this embodiment, the computer 10 can process the shape of the workpiece and the absolute coordinates of each teaching point and the absolute angle of the torch at each teaching point as data. It is possible to display the relative positional relationship with the work on the display means 24. Therefore, it is possible to determine the path of the arm or the like of the welding robot while avoiding interference with the workpiece by simulation using the display means 24. This also makes it possible to create data for the welding robot. The effect of shortening the time is obtained.

As is apparent from the above description, the present embodiment
In FIG. 1, the wire deflection of the work to be welded in S1 of FIG.
The process of displaying the robot model on the screen is called the
And the operation of the operator in step S1.
The process of specifying a specific surface element according to
Process, and according to the operation of the operator in S2
The step of designating the teaching point and S14 cooperate with each other,
The “teach point designation process” is configured, and S3 is performed by the “outline selection process”.
Step 7 constitutes "input of relative travel angle and relative aim angle".
Process ”to create point data in S2.
Steps S4 through S8 and S15 cooperate with each other,
This constitutes the “data creation process”. Although the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in various other modified and improved forms based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a welding data creation program for implementing a data creation method according to one embodiment of the present invention.

FIG. 2 is a block diagram showing a welding data creation device that creates data for a welding robot using the program.

FIG. 3 is a perspective view showing an example of a workpiece to be used for explaining the program of FIG. 1;

FIG. 4 is a perspective view showing a part of a portion where continuous fillet welding is performed in the workpiece to be welded in FIG. 3 by a wire frame model.

FIG. 5 is a diagram for explaining the program of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Computer 20 Auxiliary memory 22 Input means 24 Display means 40 Member 42 Member 50 First guide line 52 Second guide line 54 Specific surface element

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G05B 19/4093 B25J 9/10 B25J 9/22

Claims (2)

(57) [Claims] 1. A welding robot torch, the data required to move along a weld line which is assumed on the object to be welded
A method of creating with a computer , wherein the surface of the workpiece is approximated by a plurality of wires.
To be displayed on the screen as a wireframe model
Based on the object surface display step and the operation of the operator,
Of the plurality of surface elements defined by the wires
A surface element specifying step of specifying a surface element including a tangent line, and the specified surface element is specified based on an operation of an operator.
Out of a plurality of contour lines to be determined,
The teaching point designating step of designating the teaching point above and the designated teaching point
Coincides with the welding line among the plurality of outlines of the surface element
A contour line selecting step of selecting an object, and selecting the designated surface element based on an operation of an operator.
The torch is moved along the welding line
When the torch moves from the reference line extending vertically from the teaching point
It is an angle to incline in the front-back direction and the left-right direction respectively.
Relative advance angle / phase to input relative advance angle and relative aim angle
A target angle input step, the designated surface element, the designated teaching point,
The selected outline and the entered relative travel angle and
Point data defining absolute coordinates of the teaching point in the coordinate system set for the entire workpiece to be welded , based on the relative aiming angle and the relative aiming angle at the teaching point . when inclined at target angle, the data creation method for a welding robot, characterized in that it comprises a data creating step of creating and direction data defining the absolute movement angle and the absolute target angle in the coordinate system. 2. The relative advancing angle / relative aiming angle inputting step includes:
The relative travel angle and relative aim angle should be entered this time.
Value is equal to the previously entered value,
By using the value, the input of the value to be entered this time can be omitted.
The welding robot according to claim 1, which is omitted.
How to create data.