JPS5839030B2 - Teaching device for automatic welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a teaching device for an automatic welding device, and more particularly to a teaching device for an automatic welding device that uses a welding torch as a weld line detector (sensor).

Welding torch and workpiece (hereinafter simply referred to as workpiece) according to the position information and control information stored in the storage device
A playpack force-type automatic welding device is well known in which the positions of the welding device and the welding device are mutually controlled in space to automatically perform welding according to a program.

It is known that a sensor is used to cause the welding torch to follow the welding line of the workpiece.

However, conventionally, a sensor for detecting a weld line has been attached separately from the torch and in the vicinity of the torch, resulting in a large size around the torch.

Therefore, if the torch or sensor cannot enter the deep part of a narrow workpiece, or if the welding line has a small groove size, the sensor will not work effectively.

In addition, there were various problems such as the structure being complicated and expensive.

Therefore, the present inventors have previously proposed an extremely superior automatic welding device in which the torch itself acts as a sensor.

Therefore, the present invention provides a teaching device for teaching the starting point and ending point of a welding line in such an improved automatic welding device.

Before describing the present invention in detail, the configuration of the present invention will be explained based on FIG. 8.

A welding torch with an electrode is held by a welding torch holding means.

Also, the workpiece with the weld line is secured by the workpiece fixture.

The welding torch holding means and workpiece fixture are supported by support means.

The support means movably supports at least one of the welding torch holding means and the workpiece fixture to enable adjustment of the relative position of the welding torch and workpiece.

A displacement mechanism is provided in conjunction with this support means.

The displacement mechanism displaces the movable part of the support means to change the relative position of the welding torch and workpiece.

Also provided is voltage supply means for supplying voltage to the electrodes of the welding torch.

Further, energization state detection means is provided for detecting the energization state of the electrode of the welding torch.

Furthermore, sensing means for sensing is provided.

This sensing means is for sensing the position of a predetermined welding point before automatically welding a workpiece, and includes the following functional means.

That is, the sensing means includes a movement command giving means that gives a predetermined movement command to the displacement mechanism in order to bring the electrode of the welding torch and the workpiece closer to each other at a plurality of point positions crossing the welding line of the workpiece.

Further, the sensing means includes point position data generating means for generating data representing the mutual positions of the welding torch and the workpiece at that time in response to the output of the energization state detecting means at the plurality of point positions.

Further, the sensing means includes calculation means for calculating the predetermined welding point position based on the data at the plurality of point positions generated by the point position data generation means.

The above objects and other objects and features of the invention will become more apparent from the following detailed description with reference to the drawings.

FIG. 1 is an overall perspective view showing an automatic welding apparatus according to an embodiment of the present invention.

In FIG. 1, this automatic welding apparatus 100 includes a work W
(not shown) is mounted on the torch 105 so that the tool 105 can be moved left and right, forward and backward, or rotated around the horizontal axis H.
The attachments 9 are configured so that the tool 108 can be moved in the vertical direction or rotated around the vertical axis, and the workpiece W
A control box 400 including a general-purpose computer for automatically controlling the movement and rotational position of the torch 109 is provided.

Let me explain in more detail. A first frame 102 is fixedly installed on one side of the floor plate 101 having a planar shape.

A cart 103 that is movable in the left-right force direction (X-axis force direction in the figure) is provided on the upper part of the frame 102.

The power means (not shown) for this truck 103 is a known motor with a brake equipped with a speed reducer in this embodiment, and the power transmission means (not shown) is a known means for engaging a pole nut and a threaded rod (so-called ball screw).

In addition, the upper part of the trolley 103 is
A second frame 104 is provided that is movable in the axial direction.

The power means and power transmission means of this frame 104 are also a similar motor with a brake and a ball screw, although not shown.

A workpiece mounting tool 105 is provided at the front of the frame 104 and is rotatable in the θ-axis direction in the figure.

Although not shown, the power means of the tool 105 for mounting the workpiece is a known motor with a brake and a reduction gear.

A third frame 106 is erected at the other end of the floorboard 101 .

This frame body 106 has a vertical direction (X-axis force direction in the figure).
A movable arm 107 is provided.

The power means and power transmission means of this arm 107 are also a similar motor with a brake and a ball screw, although not shown.

A torch 109 is attached to the tip of the arm 107 and is rotatable around a vertical axis (Φ axis direction in the figure).
08 is provided.

Although not shown, the power means of the tool 108 for attaching the torch is a known motor with a brake and a reduction gear.

Further, the mounting position of the torch 109 is configured such that the welding point WP on the extension of the center line of the torch 109 coincides with the above-mentioned vertical axis. (welding or fillet welding, etc.) and the shape of the workpiece.

Note that the floor plate 101. Frame 102° Cart 103. Second
Frame body 104. The third frame 106 and the arm 107 constitute an example of support means.

Further, the power means and power transmission means provided in association with each support means constitute an example of a displacement mechanism.

Further, a current is applied to the torch 109 from a power supply device 200.

The control box 400 and welding control device 300 automatically control the forward rotation, reverse rotation, moving speed, welding current, etc. of the power means (motor with brake with reducer) of each part according to the program, and control the welding point WP. The two attachments control the mutual positions of the tools 105 and 108 so that the welding line of the workpiece W (not shown) is aligned and automatic welding can be performed in the position with the best welding conditions.

A remote control ("remote control") panel 500 is provided for the purpose of programming or manual operation.

Further, the control box 400 is configured as shown in FIGS. 5A to 7, which will be described later.
A program as shown in the figure is stored, and sensing and teaching operations for the welding start point position and welding end point position, which are the characteristics of this embodiment, are performed in accordance with this program.

Therefore, the control box 400 constitutes an example of sensing means.

In this embodiment, the welding point WP on the extension of the center line of the torch 109 is configured to coincide with the vertical axis, so the attachment remains constant regardless of the rotation of the tool 108 in the Φ-axis force direction. The attitude of the torch 109 with respect to the same welding point can be arbitrarily changed by rotating the attachment tool 108 (in the Φ-axis direction).

That is, this embodiment is an automatic welding device with five degrees of freedom.

FIG. 2 is an illustrative view showing the electrode supply section.

In the example shown in FIG. 2, it is assumed that the workpiece W has a fillet weld line WL as shown.

As described above, the torch 109 is attached by the torch mount 108 so as to be freely pivotable about the axis.

This torch 109 includes a consumable electrode supply means 20.
A consumable electrode from 1 is given.

The consumable electrode supply means 201 is provided, for example, in the power supply device 200 shown in FIG. 1, and includes a consumable electrode forcing device 202.

The consumable electrode forcing device 202 is, for example, a flexible tube for guiding a consumable electrode formed into a loop shape, and is intended to give a bending direction to the consumable electrode passing through the flexible tube.

However, the force device 202 may be of a type that, for example, pinches the consumable electrode with guide rollers and thereby forces it into a straight line.

The consumable electrodes supplied from the consumable electrode supply means 201 include:
A voltage from well-known voltage application means 203 is applied.

The voltage application means 203 is controlled by the changeover switch 204.
It is selectively connected to a welding power source 205 or a discharge high voltage power source 206 as a detection power source.

The welding power source 205 is a well-known welding power source and has a relatively low voltage and large current, and the discharge high voltage power source 206 has a relatively high voltage (approximately 100 to 2000 V) and a small current.

Further, the welding power source 205 is directly connected to the workpiece W,
The high-voltage power source 206 for discharging is connected to the workpiece W via a current sensor 207, which is an example of energization state detection means.

The current sensor 207 detects the current value flowing between the consumable electrode of the torch 109 and the workpiece W, and an output signal accompanying a change in the current value in this sensor 207 is given to the control box 400.

Further, the changeover switch 204 is normally switched to the welding power source 205 side as shown in FIG. has been done.

FIGS. 3 and 4 are illustrative views showing the form of a workpiece W to which the present invention is applicable.

That is, FIG. 3 shows an example of fillet welding,
FIG. 4 shows an example of butt welding with a groove.

FIGS. 5A and 5B are flow diagrams showing the operation of one embodiment of any invention.

The operation or operation of this embodiment will be explained below.

Before the operation, the teaching pattern will be explained.

Pattern: This pattern shows the accuracy of the workpiece or base material, so the welding start and end points are sensed only in teaching mode.

After that, the same position information can be used even if the workpiece is replaced. Pattern 2: In this pattern, the accuracy of the base metal is worse than in pattern 1, and the sensing operation must be taught, but the deviation is only a parallel movement, and only sensing at the welding start point is required. That's fine.

Pattern 3: In the case of pattern 2, the welding lines are deviated from being parallel, so sensing operations are required at both the welding start and end points.

First, a computer (not shown) in the control box 400 is put into a teaching mode, and an operation button (not shown) on the remote control panel 500 is operated to sense the welding torch 109 (in this case, welding) using a known playback method. Manually control movement to (near the starting point).

Then, by using a pattern selection switch provided in the control box 400, for example, it is input which of the above-mentioned patterns 1 to 3 the work corresponds to.

At the same time, it is input whether the type of base material to be taught is A (for example, in the case of fillet welding as shown in FIG. 3) or B (for example, in the case of butt welding as shown in FIG. 4).

Then, a sensing command is given. Accordingly, the computer determines whether the pattern is 1, 2, or 3.

If it is pattern 1, then the type of base material is A or B.
Determine whether

If the pattern type is other than 1, that is, 2 and 3,
The type of base material is determined after storing the neighboring position as initial position information at that time.

If the base material type is A, then the sensing A subroutine is entered, and if the base material type is B, the sensing B subroutine is entered.
enters the subroutine.

Here, the sensing operation when the base material type is A will be described with reference to FIGS. 3 and 6.

When this routine is entered, first, the system program input to the computer outputs a command to the changeover switch 204, thereby causing the switch 204 to change over.

Similarly, the system program outputs a command to lower the Z axis, that is, a command to lower the torch 109.
Torch 109 descends.

Since high voltage is applied between the electrode of the torch 109 and the workpiece W by the power supply 206, the tip of the electrode of the torch 109 is at a position P2 (the distance between the workpiece W and the tip of the electrode is about 2 mm at maximum). Sparks fly between the two.

In this way, the sensor 207 detects this current, receives Zs from the position information of the position P2 at that time, and uses this value and Zs from the command information at this step.
The computer calculates the difference JZ from 2.

At the same time, the system program raises the torch 109 by a certain amount (1 to 27 nO) to reach point P3.

Then, the computer determines the next sensing force direction X and direction (towards the right in Fig. 3) from the fact that the angle of the Φ axis is Φ1 and the difference between Xl and X2, and the workpiece W should be moved in that direction. A command is output, and the workpiece W moves to the right.

In the same manner as described above, when the electrode and the workpiece W approach each other and a spark flies at the point P4, the difference JX between the X-direction position Xs of P4 at that time and the command X2 is calculated.

Then, the workpiece W is returned by a certain amount to reach a point P5.

In this way, it is determined that sensing is complete, and based on that information, the previous command to switch 204 is erased, and switch 2
04 returns to its original state and switches to the welding power source 205 side.

Furthermore, the sensing operation when the base material type is B will be described with reference to FIGS. 4 and 7.

This embodiment is different from the examples shown in FIGS. 3 and 6 and can be applied when the angle (bevel angle) formed by the two side surfaces forming the weld line WL is not known in advance.

The welding line WL in the X-axis direction in this embodiment is a butt welding line having a groove, which is intended to be welded downward, and the torch 109 maintains a vertical posture.

First, a command is output to the changeover switch 204, whereby the switch 204 is switched to the high voltage power source 206 side, and a high voltage is applied between the electrode of the torch 109 and the workpiece W.

Then, a command to lower the Z axis, that is, a command to lower the torch 109, is output, and the torch 109 descends.

Then, at point P2 (Xl, ¥1.Z2), a spark flies, and the output signal from sensor 207 is input to the computer.

In response to this input signal, the computer takes in the position information (Xl, ¥1.Z2) of this point P2 and stores it in a certain predetermined location.

Next, since the sensor command is sensing direction -X, the sensing direction is determined based on this, and this fourth
In the case of the figure, a movement command is output to move the workpiece to the right.

Then, a spark flies at point P3 (X2, Yt. Z2), and the signal from sensor 207 is input to the computer.

This input signal captures the position information of this point P3,
Store it in a designated location.

Next, move a certain amount (welding line W) in the opposite direction to the previous movement in the X-axis direction.
A command to return (determined as appropriate depending on the size of L) is output, that is, in this case, the workpiece W moves slightly to the left.

When the point P4 (X3-Yt, Z2) is reached, a command to lower the Z-axis is output again, and the torch 109 is lowered.

Then, the sensor 20 at point P5 (X3.\1.Z3)
The signal No. 7 is input to the computer, and the position information of this point P5 is taken in and stored in a certain predetermined location.

Further move the workpiece W to the left (same direction as the previous movement in the X direction)
The command to do so is output, and the point Pa (X4,
At Yt, Z3), the signal of the sensor 207 is input to the computer, and the position information of this point P6 is taken in and stored in the same manner.

Thus, by storing the four pieces of position information by inputting the signal of the sensor 207 four times, it is determined that sensing is complete, and the intersection of the line connecting point P2P6 and the line connecting point P3P5 is calculated to obtain point P7.

Then, the aiming position of the torch 109 (usually point P7) is slightly above point P7) Ps (X5 y Yt z Z
4) is calculated.

Then, the process returns to the routine of FIG. 5A.

In this way, sensing of the welding starting point is completed.

Then, it is determined whether or not the starting point position needs to be corrected based on, for example, the relationship of unequal thickness of the work W.

If no correction is necessary, the starting point position determined by the sensing A or sensing B routine described above is stored.

If correction is necessary, the correction amount is added to the starting point position information obtained as described above to correct it, and this is stored as starting point position information.

This completes the teaching of the starting point position.

Subsequently, the welding end point position is sensed, and at this time as well, the welding torch is moved to the vicinity of the end point by operating the operation button on the remote control panel 500.

The computer then determines whether the pattern is 1, 2 or 3.

In the case of patterns 1 and 2, it is then determined whether the type of base material is A or B.

If the pattern is 3, the type of base material is determined after storing the position near the end point in l steps.

Then, if the base material type is A, the end point position is sensed by the sensing A routine described above, and if the base material type is B, the end point position is sensed by the sensing B routine described above.

Thereafter, it is determined whether or not there is a modification, and if there is a modification, the modified position is stored, and if there is no modification, the modified position is stored as is as end point position information.

In this way, the start and end points of the weld line are sensed and taught.

In the above description, the relative position of the tip of the consumable electrode with respect to the torch 109 is such that the consumable electrode always protrudes from the torch 109 in the same shape due to the action of the force device 202, and the protrusion length is such that the tip of the consumable electrode always protrudes from the torch 109 at the end of welding. It will be understood that since they are always the same, they will always be in the same relative position and will not interfere with the above-mentioned function as a sensor.

Note that by flowing gas (for example, C02) to the torch 109, more stable sensing can be performed.

According to the embodiments shown in FIGS. 4 and 7, even if the weld line WL is formed by a groove with an undefined shape,
By calculating the intersection of the side surfaces and determining the groove shape, it is possible to determine the target welding position that will give the best welding result.

Furthermore, although this embodiment has been described with respect to a straight welding line WL, even if the welding line WL is bent,
The target positions of the torch 109 at the starting point, each bending point, and the ending point may all be calculated in advance, and each point may be sequentially executed by FTP control.

Although the electrode of the torch 109 has been described as a consumable electrode,
It is clear that this could also be done with non-consumable electrodes, such as TIG welding torches.

In this way, according to the above-mentioned embodiment, since the torch electrode itself is used as a sensor, there is no structure around the torch that acts as a sensor, and therefore, the position of the weld line can be detected wherever the torch can enter. .

Therefore, not only is the structure simple, but it can also be sensed regardless of the shape or size of the weld line.

Furthermore, even if the electrode is a consumable electrode, if a force device is provided, the position of the electrode tip with respect to the torch body is always constant, and there is no problem with sensing.

Furthermore, if the detection voltage is set to a high voltage, the discharge gap will be approximately constant regardless of the state of the workpiece surface or the electrode tip, and accurate sensing is always possible.

According to the present invention, the welding line sensing operation is also taught, so even if the workpiece (base material) changes, the welding start and end points are automatically sensed and taught.

Therefore, during playback, there is no need to manually control the relative positions of the workpiece and the torch as in the past, and there are significant effects such as shortening the teaching work time and enabling accurate teaching.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view showing an automatic welding apparatus according to an embodiment of the present invention. FIG. 2 is an illustrative diagram showing details of the consumable electrode supply section. FIG. 3 and FIG. 4 are illustrative views showing an example of the form of the base metal to be welded, respectively. FIGS. 5A and 5B are flow diagrams showing the operation of one embodiment of the present invention. FIG. 6 is a flow diagram showing the sensing A routine. FIG. 7 is a flow diagram showing the sensing B routine. FIG. 8 is a block diagram showing the configuration of the present invention. In the figure, 105 is a workpiece fixture, 108 is a torch fixture, 109 is a torch, 201 is a consumable electrode supply means, 2
02 is a consumable electrode forcing device, 203 is a voltage application means, 204
205 is a welding power source, 206 is a high-voltage discharge power source (detection power source), 207 is a current sensor, W is a workpiece, WL is a welding line, and WP is a welding point.

Claims (1)

[Scope of Claims] 1. A teaching device for an automatic welding device that senses a predetermined welding point position before performing automatic welding and teaches the sensed welding point position, comprising: a welding torch 109 having an electrode; welding torch holding means 108 for holding the welding torch; voltage supply means 206 coupled to the electrode of the welding torch for supplying voltage to the electrode of the welding torch;
, a workpiece fixture 105 for fixing a workpiece having a welding line; a workpiece fixture 105 for fixing a workpiece having a welding line; Support means 101, 102, 103, 1 for movably supporting at least one force with the fixture
04,106,107゜A displacement mechanism provided in association with the support means for displacing the movable portion of the support means to change the mutual positional relationship, detecting the energization state of the electrode of the welding torch. energization state detection means 207; and sensing means 400 for performing the sensing; movement command giving means for giving a movement command to the displacement mechanism; and data representing the mutual positions of the welding torch and the workpiece at that time in response to the output of the energization state detection means at the plurality of point positions. A teaching device for an automatic welding apparatus, comprising: point position data generation means; and calculation means for calculating the predetermined welding point position based on the data at the plurality of point positions.