JPH04307604A - Data production method for welding robot - Google Patents

Abstract

PURPOSE:To reduce the data production time and to improve the date accuracy by producing the data required for a welding robot to move a torch above an object to be welded based on the shape data of the object to be welded. CONSTITUTION:The position of each teach point set on a welding line supposed on the surface of an object to be welded, the direction of the welding line set at each teach point, and relative advance angle theta and a relative aiming angle alphawhere a torch tilts in the front-back and right-left directions at each teaching point against the reference line extending vertically from each teach point set on the surface of the object to be welded are designated (S1--S3, S5, S7, S9-S11, S14). Based on these angles and the shape data of the object to be welded, the point data on a work coordinate system set to the to be welded are produced together with the direction data that prescribe the absolute advance and aiming angles in the work coordinate system when the torch tilts at both angles theta and alpha at each teach point (S4, S6, S8, S15).

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 One type of welding robot is already known that performs welding by moving a torch it holds along a welding line on a workpiece. This type of welding robot stores the positions of multiple teaching points set on the welding line that the torch should follow and the angle of the torch set at each of these teaching points along the welding line, and then Based on the teaching point information, PTP (point to po
int) According to the control method, the torch is made to follow the welding line, which is a straight line, a polygonal line, or a curved line.

[0003] In the field of welding robots, prior to welding, for example, as described on pages 265 to 266 of the document "Revised Third Edition Welding Handbook (September 20, 1980, Published by Maruzen Co., Ltd.)" Conventionally, a human manually causes a torch to follow a planned welding line and teaches the welding robot the actions to be performed. 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 in the front-back direction ( The welding robot was taught by giving the advancing angle and aiming angle, which are angles that are inclined in the welding line's advancing direction) and in the left-right direction, respectively.

0004

[Problems to be Solved by the Invention] However, it is troublesome and time-consuming for a human to manually teach the welding robot the actions to be performed one by one, and it is difficult to adjust the torch's advancing angle and aiming angle sufficiently. However, there was a problem in that it was not possible to teach with high precision. The present invention has been made with the aim of solving this problem.

[0005]

[Means for Solving the Problem] In order to solve this problem, the present invention provides a data creation method for a welding robot.
(a) shape data that defines the shape of the surface of the workpiece; (b) the position of at least one teaching point on the welding line assumed on the surface, the direction of the welding line at each teaching point, and the torch. Regarding the relative advancing angle and the relative aiming angle, which are the angles at which the torch is inclined in the front-rear direction and left-right direction at each teaching point from the reference line extending perpendicularly from each teaching point on the surface when the torch is moved along the welding line. Based on the input data, (a) point data that defines the absolute coordinates of the position of each teaching point in the coordinate system set for the entire workpiece, and (b) relative progress of the torch at each teaching point. The gist is that direction data defining an absolute advancing angle and an absolute aiming angle in a coordinate system when tilting at an angle and a relative aiming angle are created.

[0006] Note that the relative advance angle and relative aim angle may be input only once for a plurality of teaching points on the workpiece, for example.
This can be done so that a common value is set for those teaching points, or it can be done for each teaching point. In the latter case, input the torch relative angle for each teaching point by first inputting whether it is the same as the previous value, and if it is the same, use the previous value to change the current value. The input can be omitted, and if the values are not the same, the current value can be input.

[0007]

[Operation] In the data creation method for a welding robot according to the present invention, the characteristics of the welding line (each teaching point on the welding line and the direction of the welding line at each teaching point), the relative advancing angle and the relative aiming angle of the torch, is input, point data that defines the absolute coordinates of each teaching point of the torch in the coordinate system of the welded object is created, and the shape data of the welded object is used to adjust the torch and the welded object. Direction data defining an absolute advancing angle and an absolute aiming angle in the coordinate system is created. Using the shape data of the workpiece, an absolute advancing angle and an absolute aiming angle corresponding to the relative advancing angle and relative aiming angle of the torch are determined.

[0008]

[Effects of the Invention] Therefore, according to the present invention, data for the welding robot is created without manually moving the torch along the welding line, reducing the time required to teach the welding robot. You can get the effect that you can. Further, since the torch direction data is created based on the shape data of the object to be welded, the teaching accuracy of the welding robot is improved, and the welding quality is also improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A data creation method for a welding robot, which is an embodiment of the present invention, will be explained in detail below with reference to the drawings.

FIG. 2 shows a welding data creation device using this data creation method. As shown in the figure, the welding data creation device includes a computer 10. computer 1
0 is mainly composed of a CPU 12, a ROM 14, and a RAM 16. An auxiliary memory 20, input means 22 and display means 24 are connected to this computer 10. The auxiliary memory 20 stores wire frame data (this is one aspect of shape data in the present invention) that defines a wire frame model in which the surface of the workpiece is approximated by a plurality of wires (straight elements). The input means 22 includes a keyboard, a mouse, etc.
The display means 24 includes a CRT and the like. R.O.
Various programs are stored in M14, including the welding data creation program shown in the flowchart of FIG.

[0011] The operation of the present welding data creation device will be explained. As shown in FIG. 3, the two members 40 and 42, both of which have a container shape, are fitted together so that the inner edge of the cylindrical end surface of the outer member 40 and the edge of the outer surface of the inner member 42 are fitted together. An example will be explained in which continuous fillet welding is performed at the part in contact with.

When the power is turned on, the CPU 12 performs predetermined initial settings 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), wire frame data is read from the auxiliary memory 20 into the RAM 16, and based on this, a wire frame model of the workpiece is displayed on the screen of the display means 24. displayed above. For example, the circled portion in FIG. 3 is displayed as shown in FIG. 4. Based on this display result, the operator operates the input means 22 to select a specific surface element from among the plurality of wires for which a point and direction regarding the torch (hereinafter collectively referred to as teaching point information) is desired to be created. A first guide line and a second guide line are selected for definition. Of the four wires defining the specific surface element, two wires facing each other are selected. In the example of FIG. 4, it is assumed that the first guide line 50 and the second guide line 52 are selected, and the surface element 54 is set as the current specific surface element.

[0013] Thereafter, in S2, a teaching point M on a welding line planned on a specific surface element is designated in accordance with the operation of the mouse of the input means 22. Data specifying the position of the teaching point M is input into the computer 10 using the mouse, and this data is one form of input data regarding the position of the teaching point in the present invention. In the example of FIG. 4, the first guide line 50 is the welding line, but since this welding line is a straight line, the teaching point M is the end point on the welding start side of both end points of the first guide line 50 (this time (assumed to be the left end point). In this step, furthermore, the work coordinate system x of the teaching point M set for the workpiece to be welded is
The absolute coordinates on -yz are determined, and the point data defining them is stored in the RAM 16 in association with the welding order.

Subsequently, in S3, a reference point P on the welding line and forward of the teaching point M is specified in accordance with 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 (the right end point) of the first guide line 50. As a result, in the example shown in the figure, a straight line extending from the teaching point M toward the reference point P is input to the computer 10 as the welding line of the surface element 54. That is,
In this embodiment, specifying the position of the reference point P is specifying the direction at the teaching point M of the welding line, and the data specifying the position of the reference point P is the input regarding the direction of the welding line in the present invention. It is a form of data. In S4, a vector N starting from the teaching point M and extending toward the reference point P and having a length of 1 (the direction coincides with 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 determined according to the operation of the input means 22.
Whether the z-axis of the workpiece coordinate system x-y-z is in the positive or negative direction is input. For the example of FIG. 4, assuming that at teaching point M the torch is planned to take the attitude shown in FIG. 5 by vector It is input as axial direction. Subsequently, in S6, based on the wire frame data that defines the specific surface element, the normal direction and the opposite direction of the normal line of the specific surface element at the teaching point M are determined, and further, starting from the teaching point M, the above-mentioned A vector A is generated that extends parallel to the one of the two normal directions that forms a smaller angle with the direction of the torch and has a length of 1.

Thereafter, in S7, the relative advancing angle θ and relative aiming angle α of the torch are specified in accordance with the operation of the input means 22. As shown in FIG. 5, the relative advancing angle θ is such that the center line of the torch is welded from a reference line S (this is one aspect of the reference line in the present invention) passing through the teaching point M and extending parallel to the vector A. It means an angle that is inclined in the direction opposite to the direction of line movement (opposite direction to vector N), and on the other hand, the relative aiming angle α is π/2, so that the center line of the torch is welded from the reference line S. It means the angle obtained by subtracting the angle of inclination to the right of the line's traveling direction (the direction of vector O, which is the cross product of vector N and vector A). In other words, the relative advancing angle θ is the angle formed by two images in which the reference line S and the vector On the other hand, the relative aiming angle α is the angle formed by two images in which the vector O and the vector That's why. In short, in this embodiment, data specifying the relative advancing angle θ and the relative aiming angle α is one form of input data regarding the relative advancing angle and the relative aiming angle in the present invention.

Next, in S8, a vector X1 is determined, in which the vector X is parallel to the image projected onto the O-direction projection plane and has a length of 1. The relationship between vector X1 and vector A is that the angle they form is the above-mentioned relative advancing angle θ, so the inner product of vector
= 1) and COS θ. Therefore, the vector X1 is divided into three mutually orthogonal unit vectors N, A,
If expressed using O, and using the relationship expressed by the above formula, the fact that vector X1 is on the O-direction projection plane, and that vector X1 is a unit vector, the characteristics of vector You can decide.

In this step, the vector X
A vector X2, which is parallel to the image projected onto the N-direction projection plane and whose length is 1, is determined. The vector
2 and vector O, the angle they form is (π-
Since the relative aiming angle α), the inner product of the vector X2 and the vector O=the product of the length of the vector X2 (=1), the length of the vector O (=1), and COS (π−α). Therefore, the vector X2 is similarly expressed using three mutually orthogonal unit vectors N, A, and O, and the relationship expressed by the above formula and the vector X2 are N
By utilizing the fact that it is on the directional projection plane and that the vector X2 is a unit vector, the characteristics of the vector X2 can be determined. In this step, the sum of these vectors X1 and X2 is set as vector X, and the three inclination angles of this vector Direction data defining the corner is stored in the RAM 16 in association with the point data.

Thereafter, in S9, it is determined whether or not to create other teaching point information with the same torch angle for the current specific surface element. Assuming that only one piece of teaching point information is to be created for the specific surface element this time, the determination will be NO in response to the operation of the input means 22, and in S10, it is determined whether or not to create any more teaching point information for the specific surface element. In other words, it is determined whether the teaching point information creation for the specific surface element has been completed. This time, based on the above assumption,
The determination becomes YES in response to the operation of the input means 22, and S1
In step 1, it is determined whether the creation of teaching point information for the entire object to be welded has been completed. If there is an input from the input means 22 indicating that the creation is not completed, the determination will be NO.
Returning to S1, this program is executed for a new specific surface element, but if there is an input indicating that the creation of 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 out from the RAM 16 according to the welding order, and each is transformed with respect to the robot coordinate system set for the welding robot, and in S13, the transformed Point data and direction data are stored in auxiliary memory 20. This completes one execution of this program.

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

In this way, in this embodiment, the wire frame data of the workpiece is used to create point data and direction data for the welding robot, so these data can be created accurately and in a short time. , the time required for teaching the welding robot can be shortened, and welding quality can be improved.

Furthermore, in this embodiment, if the current value is the same as the previous value in each torch angle input, the input of the torch angle value is omitted, which also improves the teaching of the welding robot. The effect is that the time required is shortened.

Furthermore, in this embodiment, since the shape of the workpiece can be processed by the computer 10 as data including the absolute coordinates of each teaching point and the absolute angle of the torch at each teaching point, the torch and workpiece can be processed as data. It is possible to display the relative positional relationship with the work to be welded on the display means 24. Therefore, it is possible to determine the path of the arm, etc. of the welding robot while avoiding interference with the object to be welded by simulation using the display means 24, and this also makes it possible to create data for the welding robot. The effect is that the time involved is shortened.

Although one embodiment of the present invention has been described above in detail based on the drawings, it is possible to implement the present invention in various other forms with various modifications and improvements based on the knowledge of those skilled in the art. It is.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a welding data creation program that implements a data creation method that is an 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 above program.

FIG. 3 is a perspective view showing an example of an object to be welded used to explain the program of FIG. 1;

FIG. 4 is a perspective view showing a part of the part of the workpiece shown in FIG. 3 where continuous fillet welding is performed using a wire frame model.

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

[Explanation of symbols]

10 Computer 20 Auxiliary memory 22 Input means 24 Display means 40 Components 42 Components 50 First Kaido Line 52 Second guide line 54 Specific surface elements

Claims (1)

[Claims] 1. A method for creating data necessary for a welding robot to move a torch along an assumed welding line on a workpiece, the method comprising: (a) determining the shape of the surface of the workpiece; (b) the position of at least one teaching point on the welding line envisioned on the surface thereof, the direction of the welding line at each teaching point, and when the torch is moved along the welding line; Based on input data regarding the relative advancing angle and the relative aiming angle, which are the angles at which the torch is inclined at each teaching point in the front-back direction and the left-right direction, respectively, from a reference line extending perpendicularly from each teaching point on the surface, point data defining the absolute coordinates of the position in the coordinate system set for the entire workpiece, and the coordinates when the torch is tilted at the relative advance angle and relative aim angle at each teaching point. A data creation method for a welding robot, the method comprising creating direction data that defines an absolute advancing angle and an absolute aiming angle in a system.