JPH0442117B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention detects the position of the end face of a vertical plate of a fillet joint using a sensing means using a welding torch as a sensor that supports a welding wire set to a predetermined protrusion length. The present invention relates to a method for detecting the position of a vertical plate end face of a fillet joint using an automatic welding device.

[Conventional technology]

Generally, bridge girders are constructed by arranging multiple horizontal and vertical reinforcement members in a predetermined pattern on the main material, which is a shaped steel material.
A so-called T-shaped fillet joint (T
The joints are manufactured by arc welding.

In this case, the specifications are such that the edges on both side surfaces and the edges on both sides of the end surface of the vertical plate are fillet welded to the lower plate, and so-called square wrap welding is performed on both end surfaces of the vertical plate. Such a welding procedure involves, for example, arranging two welding torches in a twin configuration, facing each other, and positioning the two welding torches near one end face of the standing plate to emit an arc at the same time to form a bead. Weld the beads together and perform square wrap welding at the beginning, then fillet weld the edges on both sides of the standing plate, then position two welding torches near the other end face to bring the beads together and perform square wrap welding at the end. A procedure has been adopted to do so.

In order to perform square wrap welding without defects by automatic welding, it is necessary to avoid errors in cutting the vertical plate and mounting errors in the vertical plate relative to the lower plate.
It is necessary to detect the end face position of the standing plate and control the position of the welding torch based on this detected position.

For this reason, a method is used in which photoelectric detectors are installed before and after the welding torch along the direction of welding progress, and these detectors detect the end face position of the standing plate (Japanese Patent Application Laid-Open No. 1983-1999). Publication No. 220281).

Furthermore, if standing boards (reinforcing boards) are classified based on their end surface shapes, they are generally classified into scallop-type standing boards, which have an arcuate surface of a predetermined radius (so-called scallop) at the bottom of the vertical end face, as shown in Figure 4a. There are types such as a vertical end plate with a sloped surface having an inclined surface on the upper part of the vertical end surface as shown in Figure 4b, and a vertical end type vertical plate with a vertical end surface as shown in Figure 4c ( (See Figure 10 of the above publication).

(Problem to be solved by the invention) However, the conventional method introduced above has
There are problems as explained below.

In other words, when detecting the end face position of the vertical plate, in order to avoid interference between the detector itself and the surface of the lower plate, it was necessary to position the photoelectric detector above the surface of the lower plate. Rather than the corner between the end face of the upright plate and the surface of the lower plate (see Figure 4), which is preferable for controlling the torch position, only the position of the end face of the upright plate above this corner can be detected; There is a problem in that an error occurs between the corner portion and the corner portion. Note that a similar problem occurs even if an electromagnetic detector or the like is employed as the detector.

For this reason, for example, in the scalloped vertical plate shown in Figure 4a, the distance from the lower plate surface to the detector and the designed scallop radius value are However, even with this correction calculation, it may not be possible to accurately detect the required position of the end face of the upright plate due to cutting errors or the like.

As a result, it becomes necessary to compensate for the insufficiency of torch position control based on the position detected by the detector by devising welding conditions, and searching for these welding conditions sometimes takes time and effort. In addition, in the vertical plate with an inclined surface shown in Fig. 4b, if the length of the vertical end surface is short, the detector detects not the position of the vertical end surface but the position of the inclined surface continuous above it. Another problem is that the situations in which the detector can be used are limited.

This invention was made to solve the above problems, and instead of using a dedicated detector as in the past, the sensor is a welding torch that supports a welding wire set to a predetermined protrusion length. The purpose of the present invention is to provide a method that can detect the position of the vertical plate end face of a fillet joint more accurately than before using sensing means.

[Means to solve the problem]

In order to achieve the above object, the method according to the present invention includes a means for controlling the position of a welding torch in three spatial axes, and a welding wire with a predetermined projection length supported by the welding torch. Using an automatic welding device equipped with a sensing means that applies a sensing voltage between the torch and the workpiece and detects the position of the workpiece by detecting the energization state due to contact between the welding wire and the workpiece, the lower plate and the vertical plate are A method for detecting the end face position of a vertical plate of a fillet joint constituted by, the side surface of the vertical plate being
The welding torch is located approximately perpendicular to one of the axes, and the following steps are required: (a) positioning the welding torch in a position facing the side of the upright plate, and (b) moving the welding torch from this position to the lower plate. (c) After the lower plate surface position is detected by the sensing means, the welding torch is pulled back from the lower plate surface position by a predetermined distance (ΔZ ₁ ); (c) from this pulled back position; The welding torch is moved in the direction of the side surface of the vertical plate, and the side position of the vertical plate is detected by the sensing means.
Detecting P ₁ , (d) pulling back the welding torch by a predetermined distance (ΔY ₁ ) from the previous vertical plate side position, and then moving the welding torch in a direction approaching the end face of the vertical plate from this pulled back position. to move a predetermined distance (ΔX) away from the
(e) After the movement, move the welding torch from this position toward position P ₃ , which is a predetermined distance (ΔY ₁ + ΔY ₂ ) away from this position in the direction of the side surface of the standing plate; (f) as described in (e) above. determining whether or not the side position _P2 of the standing board is detected by the sensing means during the movement in step (g) above, if it is detected in step (f) above; Return to step d);
(h) If it is not detected in step (f) above, move the welding torch from position P ₃ determined in step (e) above in the direction of the lower plate, and detect the lower plate by the sensing means. After detecting the surface position, the welding torch is pulled back from the lower plate surface position by a predetermined distance (ΔZ ₂ ) to position the welding wire tip at a position close to the lower plate surface; (i) this pulling back; moving the welding torch in a direction opposite to the direction in which it approaches the end face of the standing plate in step (d) above from the position where it was moved, and storing position data of the position detected by the sensing means during this movement. It is characterized by containing.

[Effect]

From the first detected lateral position of the upright plate, which is located a distance ΔZ ₁ above the lower plate surface, the welding torch is withdrawn from this side by a distance ΔY ₁ .

Next, after the welding torch is moved by a distance ΔX in the direction approaching the end face of the vertical plate to be detected, the welding torch is moved from this position to a position away from this position by a distance (ΔY ₁ + ΔY ₂ ) in the direction of the side surface of the vertical plate. Once moved. During this movement, it is determined whether the next side position of the upright board has been detected by the sensing means. If this is detected, the welding torch is pulled back by the distance ΔY ₁ , which is less than the previous distance (ΔY ₁ +ΔY ₂ ), and the above operations are performed in the same manner again.

On the other hand, if the next side position of the vertical plate is not detected, that is, if it is determined that the welding torch has already passed the end face of the vertical plate to be detected, the welding torch will move toward the lower plate. will be moved. After the lower plate surface position is detected by the sensing means, the welding torch is pulled back and the welding wire tip is positioned close to the lower plate surface. Next, the welding torch is moved in a direction opposite to the direction in which it approaches the end surface of the standing plate, and position data of the position detected by the sensing means during this movement is stored. Thereby, the position of the end face of the upright plate near the surface of the lower plate can be detected.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 is a perspective view of a portal welding robot for fillet welding (hereinafter referred to as a welding robot), which is a type of automatic welding equipment to which the method according to the present invention is applied, and the symbols 1a and 1b shown in the figure are These are guide rails laid at predetermined intervals, and the welding robot main body runs on these guide rails 1a and 1b.

The welding robot main body has guide rails 1a and 1b.
A portal beam 2 is arranged in a direction perpendicular to the direction (X direction in the diagram) (V direction in the diagram), and is fixed to each leg of this portal beam, and is mounted on the guide rails 1a and 1b via wheels. is supported by a pair of gate-shaped carts 3a and 3b that run in the X direction in the figure and constitute the X-axis, a transverse cart 4 that runs on the gate-shaped beam 2 and forms the Y-axis, and this transverse cart 4, The lift arm 5 moves up and down in the Z direction in the figure, which is perpendicular to the X and Y directions, and constitutes the Z axis. It consists of a pair of welding heads 6a and 6b which are supported by the welding head.

Furthermore, each of the welding heads 6a and 6b is provided with a T-axis slider 6at and 6 that constitute a T-axis by a slide mechanism that is movable in the T direction, which is the same direction as the X direction in the figure.
bt, V-axis slider 6av, which constitutes the V-axis with a slide mechanism movable in the V direction, which is the same direction as the Y direction;
6bv, and U-axis sliders 6au and 6bu which constitute a U-axis by a slide mechanism movable in the U direction, which is the same direction as the Z direction.

A welding torch 7a (hereinafter referred to as a torch) is attached to the tip of one welding head 6a.
In this case, the welding wire 7aw is passed from one wire pack 8a placed on the portal trolley 3b to the corresponding push side wire feeder 9a and pull side wire feeder 10a via a conduit cable 11a. (hereinafter referred to as wire) is fed. Similarly, the torch 7b attached to the tip of the other welding head 6b is supplied with a wire from the other wire pack 8b on the portal carriage 3b via the corresponding push side and pull side wire feeders 9b, 10b. A wire 7bw is fed through a conduit cable 11b. Also,
A control device 12, an operation panel 13, and welding power sources 14a and 14b are mounted on one of the gate-shaped carts 3a.

The control device 12 is equipped with a microcomputer, and controls the shape of a workpiece (in this case, the aforementioned bridge girder having a plurality of fillet joints made up of a lower plate and an upright plate) created in advance using a CAD system or the like. , NC data (numerical data) regarding dimensions, etc.
An NC control device for converting the coordinates of the above into the coordinates of the spindle system consisting of X, Y, Z and θ according to a predetermined procedure, and each axis of the spindle system is configured according to the control commands of this NC control device. A spindle system servo unit that drives and controls the above-mentioned, and an auxiliary consisting of the T, V, and U used to correct the torch position given by the NC-controlled spindle system by means including the method according to the present invention. It consists of an auxiliary shaft system servo unit, etc. that drives and controls the components of each axis of the shaft system. In addition, the welding power sources 14a and 14 are
Welding conditions are commanded in b.

Furthermore, a wire 7aw is provided in the welding power source 14a.
A sensing power source is provided that applies a sensing voltage (different from the welding voltage) for a predetermined period of time between the torch 7a that supports the torch 7a and the workpiece to be welded. Further, in the control device 12, there is provided an energization detection device that detects the energization state due to contact between the wire 7aw and the cook when the sensing voltage is applied, and outputs a command signal to capture workpiece position data when energized. The sensing power source and energization detection device constitute a sensing means for detecting the position of the workpiece. Then, if necessary, sensing means corresponding to the other torch 7b that supports the welding wire 7bw is provided. Note that the method according to the present invention includes the control device 12
The process is carried out according to a predetermined program executed by a microcomputer installed in the computer.

Next, an embodiment of the present invention carried out using the above-mentioned welding robot will be described with reference to FIGS. 1a and b, which are flowcharts of an embodiment of the method according to the present invention, and FIG. 2, which is an explanatory diagram of the method according to the present invention. The method according to the present invention will be described below with reference to explanatory diagrams of the method according to the present invention for vertical boards having various end face shapes as shown in FIGS. 3a to 3c.

In the explanation of the flowchart shown in Fig. 1 a and b, N1, N2, ... indicate the number of the processing procedure (step), and Fig. 2 and Fig. 3 a to c show the trajectory of the wire tip. Shown schematically. Also, the second
As shown in the figure, the side FS of the standing board F is in the Y direction (-
Y direction).

First, as shown in FIG. 2, while supporting the wire 7aw with a predetermined protruding length,
The torch 7a forming a torch angle of, for example, 30 to 50 degrees with respect to DF is positioned at position _PK , and a sensing voltage is applied to it (step N1). This position P _K (point where the tip of wire 7aw is located)
is the position facing the side FS of the standing board F,
It is determined in advance based on the NC data described above.

Then, the torch 7a is lowered from this position _PK in the Z direction input in advance, and the sensing means detects the surface position _Ps of the lower plate D (step N2).

Next, the torch 7a is raised from this lower plate surface position _Ps by a distance _ΔZ1 in the -Z direction input in advance, and then pulled back (step N3). Here, the distance ΔZ ₁ is a predetermined distance, and its value is shorter than the minimum scallop radius R of the scalloped standing board.

Furthermore, from this pulled back position, the torch 7a
is moved in the Y direction input in advance, and the position P ₁ of the vertical plate side SF is detected by the sensing means,
The position data is memorized (step N4).

Then, the torch 7a is pulled back by a predetermined distance _ΔY1 in the -Y direction inputted in advance from the previous side surface position of the standing plate (step N5).

Subsequently, the torch 7a is moved from this pulled back position to a position that approaches the end face FE of the upright plate F by a distance ΔX in a predetermined direction (in this case, the X direction) (step N6). here,
The distance ΔX is a predetermined distance, and its value is the same value as the previous distance ΔZ ₁ in this embodiment.

After the movement, the torch 7a is moved toward a position _P3 that is a predetermined distance (ΔY ₁ +ΔY ₂ ) away from this position in the Y direction (step N7).
Here, the distance ΔY ₂ is a predetermined distance, and its value is at least smaller than the plate thickness t of the standing plate F, for example, about 1/2 of the plate thickness t.

During this movement, it is determined whether the next side position _P2 of the upright board F has been detected by the sensing means (step N8).

If it is detected in step N8, that is, if it is determined that the torch 7a moved in the X direction has not yet passed the end face FE of the vertical plate, the detected vertical plate surface position _P2 Store the position data and update the previously stored position data for the side position of the standing board (step
N9). Then, return to step N5.

On the other hand, if it is not detected at step N8,
In other words, if it is determined that the torch 7a has already passed the end face FE of the standing plate, the position
The movement of the torch 7a is stopped at _P3 (step N10).

Next, it is determined whether the type of standing board F has been input in advance (step N11).

The case where the type of standing board F is not input will be described below. Note that if it has been input in advance, the process moves to step N23, which will be described later. (If the type of standing board F is known in advance, this step N11 is unnecessary.) If it is not input in step N11, the torch 7a is set in advance from position _P3 as shown in FIGS. Distance ΔZ ₃ in −Z direction
The robot is then raised towards position _P4 , which is a distance away (Step N12). Here, the distance ΔZ ₃ is a predetermined distance, and its value is the same as the minimum scallop radius R of the scalloped standing board.

During this movement, it is determined whether the position of the standing board has been detected by the sensing means (step N13).

If the position of the standing board is detected in step N13 as shown in FIG. 3a, it is determined that this standing board F is a scalloped standing board (step N14),
Return the torch to position P ₃ (step N15).

On the other hand, if it is not detected at step N13 (see Figure 3 b and c), the torch 7 is turned off at position _P4.
Stop the rise of a (step N16). From this, it is determined that the standing board F is a vertical end-face type standing board or a type standing board with an inclined surface other than a scalloped standing board.

Next, step the torch 7a from position _P4 .
It is moved toward position P5 located in the opposite direction (-X direction) to the predetermined direction (X direction) approaching the vertical plate end face FE at _N6 (step N17). Here, the value P ₂ in the X direction of the position P ₅ or the position data of the position P ₁ is used.

During this movement, it is again determined whether the position of the standing board has been detected by the sensing means (step N18).

At step N18, as shown in Figure 3b,
If the position of the standing board is not detected, it is determined that this standing board F is a standing board with an inclined surface (step N19), and then the torch 7a is returned to position _P3 (step N20).

On the other hand, if the position of the standing board is detected in step N18 as shown in Figure 3c, it is determined that this standing board F is a vertical end face type standing board (step N18).
N21), then return the torch 7a to position _P3 (step N22).

Now, if the type of standing board F has been input in advance in step N11 above, or
After the torch 7a is returned to position _P3 by either step N15, step N20, or step N22,
The following steps are performed. (See Figures 3 a to c) The torch 7a is lowered from this position P ₃ in the Z direction input in advance, and the position P _E of the lower plate surface DF is detected by the sensing means (step
N23).

Then, move the torch 7a to this lower plate surface position P _E
The wire 7aw is raised by a distance ΔZ ₂ in the -Z direction input in advance and pulled back, and the tip of the wire 7aw is positioned close to the lower plate surface DF (step N24). Here, the value of ΔZ ₂ is approximately 2 mm.

Then, from this pulled back position, the torch 7a
in the predetermined direction (X direction) and the opposite direction (-X direction) approaching the vertical plate end face FE at step N6.
direction), and the position data of the position P _x detected by the sensing means during this movement is stored (step N25).

Thereby, the end face position FE of the upright plate near the lower plate surface DF can be reliably detected. The position data for the position P _x to be stored may be only the value in the X direction, or the values in the X, Y, and Z directions may be stored, and the corner position can be determined using the values in these three directions and the value of ΔZ ₂ . It may also be determined by calculation.

Further, the position of the other end face of the upright plate F can also be detected in the same manner as described above.

In addition, in the above-mentioned embodiment, since the type of the upright plate F can also be detected based on the difference in end face shape, welding conditions can be commanded in accordance with the detected type of the upright plate F. If the type of the standing board F is known in advance, the detected standing board side position P ₁ ,
There is no need to store the position data of P ₂ , and the distance ΔZ ₁ ,
What is necessary is to determine the value of ΔX. Furthermore, in the above embodiment, an example was shown for so-called horizontal fillet welding, but since the method according to the present invention detects the position of the vertical plate end face of a fillet joint composed of a lower plate and a vertical plate, The position of the fillet joint is not limited.

〔Effect of the invention〕

As described above, according to the method of the present invention, when detecting the position of the vertical plate end face of a fillet joint composed of a lower plate and a vertical plate, sensing is performed using a welding torch provided in an automatic welding device as a sensor. By detecting the positions of the lower plate and the upright plate in a certain order using a method, it is possible to reliably detect the end face position of the upright plate near the surface of the lower plate, so there is no cutting error in the upright plate. Even if there is a mounting error of the vertical plate relative to the lower plate, the end face position of the vertical plate can be detected more accurately than before.

As a result, the dimensions of the standing board that have been entered in advance,
Data related to the position, etc. can be corrected based on the detected end face position data of the standing plate, and appropriate welding torch position control can be performed, so welding conditions can be adjusted to compensate for the insufficiency of conventional torch position control. Search work and rework are no longer necessary, contributing to the efficient production of defect-free welded structures.

[Brief explanation of the drawing]

Figures 1a and b are flowcharts of one embodiment of the method according to the invention, Figure 2 is an explanatory diagram of the method according to the invention, and Figures 3a, b and c are the invention for vertical plates having various end shapes. Figures 4a, b and c are explanatory diagrams of vertical plates having various end shapes, and Figure 5 is a perspective view of a portal welding robot for fillet welding to which the method according to the present invention is applied. be. 1a, 1b...Guide rail, 3a, 3b...Portal truck, 4...Transverse truck, 5...Elevating arm, 6a, 6
b...Welding head, 6at, 6bt...T-axis slider, 6
av, 6bv...V-axis slider, 6au, 6bu...U-axis slider, 7a, 7b...welding torch, 7aw, 7bw
...Welding wire, 12...Control device, 14a, 14b
...Welding power source, F...Vertical plate, FE...Vertical plate end surface, FS...Vertical plate side surface, D...Bottom plate, DF...Bottom plate surface.

Claims (1)

[Claims] 1. A means for controlling the position of the welding torch in three spatial axes, and a sensing device between the welding torch and the workpiece with the welding torch supporting a welding wire set to a predetermined protrusion length. Using an automatic welding device equipped with a sensing means that detects the position of the workpiece by applying voltage and detecting the energization state due to contact between the welding wire and the workpiece, welding is performed using an automatic welding device that is equipped with A method for detecting the end face position of a vertical plate of a joint, wherein the side surface of the vertical plate is positioned approximately at right angles to one of the three axes, and the automatic welding device includes the following steps: A method for detecting the position of the vertical plate end face of a fillet joint. (a) Position the welding torch in a position facing the side surface of the standing plate. (b) Move the welding torch from this position toward the lower plate. After detecting the lower plate surface position using the sensing means, The welding torch is pulled back by a predetermined distance (ΔZ ₁ ) from this lower plate surface position (c) The welding torch is moved in the direction of the side surface of the vertical plate from this pulled back position, and the side surface position P ₁ of the vertical plate is detected by the sensing means. (d) Pull back the welding torch by a predetermined distance (ΔY ₁ ) from the previous position on the side of the vertical plate, and then move the welding torch from this pulled back position in a predetermined direction approaching the end face of the vertical plate. Distance (Δ×)
(e) After moving, move the welding torch a predetermined distance (ΔY ₁ + ΔY ₂ ) from this position toward the side of the standing plate.
(f) Determine whether or not the side position P ₂ of the standing board is detected by the sensing means during the movement in step ( _e ) above (g) If detected in step (f) above, return to step (d) above (h) If not detected in step (f) above, move the welding torch to step (e) above. After moving from the predetermined position P ₃ toward the lower plate and detecting the lower plate surface position by the sensing means,
Pull the welding torch back from this lower plate surface position by a predetermined distance (ΔZ ₂ ) and position the welding wire tip at a position close to the lower plate surface (i) From this pulled back position, move the welding torch from the above (d) )
It is moved in the opposite direction to the direction in which it approaches the end surface of the standing board in step , and the position data of the position detected by the sensing means during this movement is stored.