JP2003225765A - Position detecting method in automatic welding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position detecting method in an automatic welding machine capable of correctly detecting a root gas of a weld joint. <P>SOLUTION: The root gap of the weld joint is sensed, and if the detected value is outside a permissible range, sensing is performed again at a position separate from the previous sensing position by a predetermined distance in the direction of the weld joint. If the re-sensed value is outside the permissible range, the sensing position is shifted to the next weld joint. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a position of a root gap (hereinafter referred to as a gap) in an automatic welding device.

[0002]

2. Description of the Related Art Conventionally, a sensing position S1 on the leading end side of a straight planned welding line P composed of a column 51 and a joint piece 52
And the laser sensor is scanned from the end side sensing position S2 toward the planned welding line P to sense the edge portion 52a of the joint piece 52 (that is, the gap width of the planned welding line P), and the edge portion 52a cannot be sensed for some reason. In the case of (1), it is known that sensing scanning is automatically repeated (sensing retry).
-103870 gazette and FIG. 3 of the same gazette).

[0003]

In the prior art, when the edge portion 52a cannot be sensed, the sensing retry scanning operation is the same as the first sensing scanning operation, and the edge portion 52a by assembling the column 51 and the joint piece 52 is formed. Is impossible (that is, the gap width of the planned welding line P is zero), a sensing error will eventually occur even if the sensing retry scanning is performed, and it is impossible to detect that the gap width is zero. .

The present invention has been made to solve the above problems, and an object thereof is to provide a position detecting method in an automatic welding apparatus capable of accurately detecting the root gap of a welded joint. is there.

[0005]

In order to achieve the above object, the invention of claim 1 senses a root gap of a welded joint, and when the detected value is outside an allowable range, the welding is performed from the sensing position. Re-sensing at a position separated by a predetermined distance in the welded joint direction (sensing retry)
If the sensing detection value is out of the allowable range again, the process proceeds to the next welded joint.

According to a second aspect of the invention, in the above-mentioned first aspect of the invention, sensing is repeated a predetermined number of times.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration of an automatic welding apparatus and its control apparatus applied to a position detecting method in an automatic welding apparatus of the present invention.

The automatic welding apparatus 1 of this example is composed of a robot body 2
And a welding power source 5 of an external device that supplies welding power to a welding torch 3 provided at the tip of the wrist of the robot body 2 and an object to be welded (hereinafter referred to as a work) 4, a memory reproduction control of the robot body 2 and its control. The robot control device 6 controls the welding power source 5 during the welding operation.

The robot main body 2 is, for example, a 6-axis vertical multi-joint type, and a welding torch 3 is provided at the tip of the wrist portion of the tip arm. The robot main body 2 performs an operation based on a teaching work performed by a teaching work input device which is a teaching pendant, and reproduces a welding torch tip based on teaching program execution data created by the teaching work.

The welding power source 5 is, for example, a carbon dioxide gas shielded consumable electrode welding system, and serves as both a welding power source power source for supplying welding power to the welding torch 3 and the workpiece 4 and a sensing power source. Has become. The welding power supply power supply unit receives welding start / end commands and welding condition commands such as welding current / voltage from the welding power supply control unit 22 of the robot controller 6, and supplies welding power according to the welding condition command to the welding torch 3 and the workpiece. 4 and supply. The sensing power supply is
A sensing voltage is supplied to the welding torch 3 and the work 4 in response to a sensing start / end command from the welding power source control unit 22 of the robot controller 6.

The robot controller 6 includes an arithmetic processing unit 7
1, a storage device 8, a robot body controller 9 for controlling the position of each arm of the robot body 2, an external controller 10 such as a welding power source 5, and an input device 11.

The arithmetic processing unit 7 includes a robot operation arithmetic unit 1
2, a gap calculation unit 13, a gap sensing retry calculation unit 14, and a skip calculation unit 15.

The robot operation calculation unit 12 includes a teaching operation command operation of the robot main body 2, a robot main body 2 and a welding power source 5.
Performs the playback calculation command operation by and.

The gap calculator 13 performs a sequential gap sensing calculation command operation such as the groove route gap detection method by the arc welding robot previously proposed by the applicant (Japanese Patent Laid-Open No. 5-329644). The detection information is output to the calculation unit 12, each detection information based on the gap sensing operation is input from the gap sensing detection control unit 21, and each detection position information is input from the robot operation calculation unit 12 to perform the gap calculation operation.

The groove root gap detection method by an arc welding robot proposed in Japanese Patent Laid-Open No. 5-329644 is such that a predetermined depth is set with respect to a set groove depth from the surface of at least one weld joint forming member. The detection start position is obtained, both groove faces in the groove width direction are detected at this detection start position, and the difference between the detected position data of both groove faces and the set groove depth and the detection start position is detected. And a groove root gap (gap) is obtained based on a preset angle of the groove surface.

Gap sensing retry calculation unit 14
Inputs the gap calculation value from the gap calculation unit 13,
A comparison calculation operation is performed between the gap calculation value and the gap allowance value. Then, the gap sensing retry calculation unit 14
If the calculation result is outside the allowable range, the retry position information and the number of retries are input from the gap sensing retry setting storage unit 19, and the retry position is output to the robot operation calculation unit 12 and the gap calculation unit 13 is calculated.
Then, the gap sensing retry signal is output a predetermined number of times, the gap calculation value from the gap calculation unit 13 is input again, and the comparison calculation operation is performed a predetermined number of times. Further, the gap sensing retry calculation unit 14 outputs to the skip calculation unit 15 a skip signal of the welded joint, which is the calculation result of the outside of the allowable range at the retry position.

The skip calculation unit 15 inputs the skip signal from the gap sensing retry calculation unit 14 and calculates the presence / absence of the next welding joint from the teaching program execution data in the teaching program storage unit 16 to determine whether the next welding joint is present. Based on the calculation result, a movement operation command to the next welding joint is output to the robot operation calculation unit 12.

The storage device 8 is a teaching program storage unit 1.
6, a gap sensing operation storage unit 17, a gap allowable value storage unit 18, a gap sensing retry setting storage unit 19, and a primary storage unit 20.

The teaching program storage section 16 stores a teaching program for each work 4 by teaching work.

The gap sensing operation storage unit 17 stores a sequential gap sensing operation.

The allowable gap value storage unit 18 stores the allowable gap value for each gap welded joint. For example, if the gap is too narrow, defects such as cracks are likely to occur in a groove of V-shaped or V-shaped groove, and if the gap is too wide, the molten pool flows from the arc point in the welding progress direction, and thus melts. Becomes shallower and lacks in melting,
Since defects such as poor fusion are likely to occur, the gap (= allowable gap value) that allows normal welding is 3 to 12.
It will be about mm. When gap sensing is performed at multiple locations within the same welding line and the change can be predicted, whether the difference between the maximum and minimum gap values detected at multiple locations is within the allowable range, and whether gap sensing is possible. Whether or not the degree of change of the gap with respect to the point-to-point distance is within the allowable range can be used as a criterion for determining the allowable gap value.

Gap sensing retry setting storage unit 1
Reference numeral 9 stores retry position information and the number of retries at the retry position. For example, the retry position is a position moved in the welding direction from the original gap sensing position, and the movement amount at that time is about 1 to 10 mm. The welding direction is divided into the welding start end side and the welding end side.However, in order to secure a long movable distance, the retry position on the welding start end side is normally set to the end position, and the retry position on the welding end side is set to the start end position. It is desirable to do. Further, in the case of a welded joint including welding of the R portion, such as a square pipe, it is desirable to move the welded joint away from the R portion. On the other hand, the number of retries is about the number of times that the distance from the original position is within 50 mm. However, retry direction / distance /
The number of times is different depending on the length and shape of the welding line, and the above numerical values are one example.

The primary storage unit 20 stores each detection information by the gap sensing operation and each calculation unit 12 such as a gap calculation value.
The calculated values at 15 are temporarily stored.

The robot main body control device 9 controls the movement of the robot main body 2 in accordance with a teaching calculation command from the robot operation calculation unit 12.

The external controller 10 comprises a gap sensing detection controller 21 and a welding power source controller 22.

The gap sensing detection control unit 21 gaps a sequential gap sensing operation command such as a groove route gap detecting method by an arc welding robot previously proposed by the applicant (Japanese Patent Laid-Open No. 5-329644). It outputs to the calculation unit 13, detects the contact between the welding wire and the groove of the weld joint due to each gap sensing operation, and outputs this detection signal to the gap calculation unit 13.

The welding power source control unit 22 outputs a welding start / end command, a welding current / voltage welding condition command, etc., which are input from the robot operation calculation unit 12, to the welding power supply power source unit of the welding power source 5, and at the same time inputs The sensing start / end command is output to the sensing power supply unit of the welding power supply 5.

The work 4 by the automatic welding apparatus 1 having the above-mentioned configuration
An outline of the position detecting operation of the root gap 23 will be described with reference to FIGS.

The rectangular groove in the work 4 is formed by the welded joint forming members 24 and 25 and the backing material 26.
In this example, welding is performed in the direction indicated by arrow X. In this case, sequential gap sensing is performed at the welding start position A, such as the groove root gap detection method (Japanese Patent Laid-Open No. 5-329644) by the arc welding robot previously proposed by the applicant. By this execution, the value g of the gap 23 is obtained from the shape of the groove 27 as shown in FIG. 3a. This value g is the permissible gap range (g1 to g for the normal groove 27 as shown in FIG. 3a).
Although it can be obtained as a value in 2), for example, when the gap 23 is measured by touch sensing, as shown in FIG.
In the case where 8 is attached, the value becomes smaller than the lower limit value g1 of the allowable gap range, and the value is out of the allowable gap range.

Therefore, in the present invention, assuming such a case, the gap value g calculated in the first calculation of the welding start side position A becomes a value outside the allowable gap range (g1 to g2). In this case, as shown in FIG. 2b, at a position A2 separated from the initial position A1 by a predetermined distance (about 1 to 10 mm) in the welding direction, the sequential gap sensing is performed again in the same manner as that performed at the position A1. Run. Then, even at the position A2, a similar defect in which the calculated gap value g deviates from the allowable gap range (g1 to g2) is assumed. Therefore, assuming that such a problem occurs, the position is further changed by a predetermined distance in the welding direction. A predetermined number of times (3
Sequential gap sensing is performed at the welding start side position A repeatedly.

If the gap value g within the allowable gap range (g1 to g2) is obtained by the sequential gap sensing according to the above procedure, the existence of the gap 23 at the welding start side position A is confirmed. Next, the sequential gap sensing is performed at the welding end side position B in the same manner as above. By this execution, if the gap value g within the allowable gap range (g1 to g2) is obtained even at the welding end position B, it is confirmed that the gap 23 within the allowable gap range (g1 to g2) exists. It will be. Due to the presence of the gap 23 between the welding start side position A and the welding end side position B, the allowable gap range (g1
The presence of the gap 23 in g2) has been accurately detected.

Work 4 by the automatic welding device 1 having the above-mentioned configuration
The position detecting operation of the gap 23 will be described in more detail below with reference to the flowcharts of FIGS. In the description of the flowcharts of FIGS. 4 to 9, S1 to S
32 shows the number of each processing procedure (step).

In step S1, the operator teaches the work program No. 4 of the work 4 including a plurality of gap welded joints.
Is set and input from the input device 11 and is started up.

In step S2, the robot operation calculation unit 12 of the robot control device 6 sets the setting N by the above starting operation.
o. The teaching program execution data of 1 is sequentially read from the teaching program storage unit 16 and the robot main body 2 is operated according to the teaching program execution data via the robot main body control device 9 of the robot control device 6.

In step S3, the execution of the teaching program progresses, and the robot motion calculation unit 12 causes the gap sensing detection control unit 21 of the robot control device 6 to send the welding start side position A ( The sensing command in (see FIG. 2) is issued.

In step S4, the gap sensing detection control unit 21 reads the predetermined gap sensing operation sequence of the joint groove from the gap sensing operation storage unit 17, and based on this sequence, the robot operation calculation unit 12 causes the robot body controller 9 to operate. The robot body 2 is caused to perform a gap sensing operation via the.

In step S5, each sensing detection signal by the gap sensing operation is output from the gap sensing detection control section 21 and the sensing detection position information is output from the robot operation calculation section 12 to the gap calculation section 13 to calculate the gap value. .

In step S6, it is determined whether or not the calculated gap value is outside the preset allowable gap value range. At this time, if the calculated gap value is outside the range of the allowable gap value, the process proceeds to step S18 shown in FIG.

In step S18, another gap sensing command is output at a position (position A2 in FIG. 2b) separated by a predetermined distance in the traveling direction of the welded joint.

In step S19, based on the output of the gap sensing command again, the gap sensing detection control unit 21 reads the predetermined gap sensing operation sequence of the joint groove from the gap sensing operation storage unit 17, and based on that sequence, The robot operation calculation unit 12 causes the robot body 2 to perform a gap sensing operation via the robot body controller 9.

In step S20, each sensing detection signal by the gap sensing operation is output from the gap sensing detection control section 21, and sensing detection position information is output from the robot operation computing section 12 to the gap computing section 13 to compute the gap value. .

In step S21, it is determined whether or not the recalculated gap value is outside the preset allowable gap value range. At this time, if the calculated gap value is again outside the range of the allowable gap value, the subsequent step S
In 22, it is determined again how many times the gap sensing has been executed, and if it has been executed a predetermined number of times, the process proceeds to step S17. On the other hand, when the predetermined number of times has not been executed, the process proceeds to step S18.

Also, the calculation gap value in step S6,
Alternatively, if it is determined again in step S21 that the calculated gap value is within the allowable gap value range, the process proceeds to step S7.

In step S7, subsequently, a sensing command is output from the robot motion computing unit 12 to the gap sensing detection control unit 21 based on the gap sensing execution data at the welding end position B (see FIG. 2).

In step S8, the gap sensing detection controller 21 causes the robot body 2 to perform the gap sensing operation via the robot body controller 9 based on the predetermined gap sensing sequence of the joint groove.

In step S9, each sensing detection signal by the gap sensing operation is output from the gap sensing detection control section 21 and the sensing detection position information is output from the robot operation calculation section 12 to the gap calculation section 13 to calculate the gap value. .

In step S10, it is determined whether the calculated gap value is outside the preset allowable gap value range. At this time, if the calculated gap value is outside the range of the allowable gap value, the process proceeds to step S23 shown in FIG.

In step S23, another gap sensing command is output at a position separated by a predetermined distance in the direction opposite to the traveling direction of the welded joint.

In step S24, based on the output of the gap sensing command again, the gap sensing detection control unit 21 reads the predetermined gap sensing operation sequence of the joint groove from the gap sensing operation storage unit 17, and based on that sequence, The robot operation calculation unit 12 causes the robot body 2 to perform a gap sensing operation via the robot body controller 9.

In step S25, each sensing detection signal by the gap sensing operation is output from the gap sensing detection control section 21 and the sensing detection position information is output from the robot operation calculation section 12 to the gap calculation section 13 to calculate the gap value. .

In step S26, it is determined whether or not the recalculated gap value is outside the preset allowable gap value range. At this time, if the calculated gap value is again outside the range of the allowable gap value, the subsequent step S
In 27, it is determined again how many times the gap sensing has been executed, and when it has been executed a predetermined number of times, the process proceeds to step S17. On the other hand, if the predetermined number of times has not been executed, the process proceeds to step S23.

If it is determined that the calculated gap value in step S10 or the calculated gap value again in step S26 is within the allowable gap value range, step S1.
Move to 1.

In step S11, the gap sensing retry calculation unit 14 determines whether or not there is a sensing retry.

In step S12, it is determined whether or not the two gaps at the welding start position A and the welding end position B are outside the allowable gap range. At this time, if it is determined that the calculated gap values at the two locations are not outside the range of the allowable gap value, the process proceeds to step S28 shown in FIG.

In step S28, after confirmation, the robot operation calculation unit 12 outputs a command to the welding power source control unit 22 of the robot controller 6 to supply welding power to the welding torch 3 of the robot body 2 via the welding power source 5. To be done.

At the same time, in step S29, the robot body 2 is welded through the robot body controller 9 in accordance with the teaching program execution data.

In step S30, after the welding is executed, the robot operation calculation unit 12 stores the teaching program execution data up to the ending execution data of the teaching program in the teaching program storage unit 1.
The robot main body 2 is operated in accordance with the teaching program through the robot main body controller 9 by sequentially reading from the robot 6.

In step S31, the robot operation computing section 12 confirms from the teaching program storage section 16 whether or not there is welding start execution data before the end execution data of the teaching program.

In step S32, it is determined whether or not there is a next welded joint. At this time, if it is determined that there is no next welded joint, the teaching program is ended. On the other hand, if it is determined that there is a next welded joint, the process proceeds to step S3 in FIG. 4 and gap sensing is performed on the new welded joint.

Further, in step S12, it is judged whether the gaps at the two positions of the welding start side position A and the welding end side position B are out of the allowable gap range. If it is determined that there is one, the process proceeds to step S13.

In step S 13, the gap sensing retry calculation unit 14 inputs the retry position information and the number of retries from the gap sensing retry setting storage unit 19, outputs the retry position to the robot operation calculation unit 12, and outputs the gap calculation unit 13 to the gap calculation unit 13. The sensing retry signal is output a predetermined number of times, the calculated gap value from the gap calculator 13 is re-input, and the presence or absence of a predetermined number of sensing retries is calculated.

In step S14, based on the above calculation, it is determined again whether or not the gaps at the welding start position A and the welding end position B are both outside the allowable gap range. At this time, if it is determined that neither of the two calculation gap values is out of the allowable gap value range, the process proceeds to step S28 shown in FIG. 9 as in step S12, and step S2 is performed.
8 to 32 are executed.

Further, in step S14, it is judged whether the gaps at the two positions of the welding start side position A and the welding end side position B are out of the allowable gap range. If so, then FIG.
Then, the process proceeds to step S15.

In step S15, it is determined whether or not the next sensing retry is performed. If there is, the process proceeds to step S13, and the sensing retry is repeated. On the other hand, if not present, the process proceeds to step S16.

After the determination in step S16, the robot operation calculation unit 12 determines from the teaching program storage unit 16 whether the welding start execution data is present before the end execution data of the teaching program.
Confirm.

In step S17, it is determined whether or not there is a next welded joint. At this time, if it is determined that there is no next welded joint, the teaching program is ended. On the other hand, if it is determined that there is a next welded joint, the process proceeds to step S3 in FIG. 4 and gap sensing is performed on the new welded joint.

As described above, according to the position detecting method in the automatic welding apparatus of the present embodiment, at the welding start side position and the welding end side position, the calculation is performed by executing the sequential gap sensing at each initial position. Even if the gap value is outside the allowable gap range, the sensing position is moved a predetermined distance in the welding direction and the sequential gap sensing is performed again a predetermined number of times in the same manner. If a gap value that falls within the allowable gap range is found between the position and the welding end position, it is confirmed that there is a root gap within the allowable gap range, and the allowable gap between the welding start side and the welding end side is confirmed. It can be accurately detected that a root gap within the range exists.

In the above example, the welding start side position A and the welding end side position B are described as an example, but the present invention is not limited to this example. It may be at two or more positions of A and the intermediate position,
Further, the number of positions may be three or more, including the welding end side position B. In short, it can be accurately detected that the root gap within the allowable gap range exists between the welding start side and the welding end side. It may be two or more places.

[0069]

As described above, according to the first aspect of the present invention.
According to the position detection method in the automatic welding device according to the above, it is possible to accurately detect the presence or absence of the root gap at each of the sensing positions before and after the welding direction in the welded joint, and thereby to detect whether there is a normal gap before and after the welding direction. It can be accurately detected that the root gap is formed and present.

According to the second aspect of the present invention, since the root gap is sensed a predetermined number of times while changing the sensing position in the welding direction, unnecessary sensing is not performed. It is possible to perform efficient sensing, and it can be expected that the welding work efficiency of the welded joint will be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an automatic welding device and a control device thereof applied to a position detection method in an automatic welding device of the present invention.

FIG. 2 is an explanatory view of a welded joint for explaining the position detecting operation of the groove root gap by the automatic welding device applied to the position detecting method in the automatic welding device of the present invention, in which a is a groove portion. 3 is an overall view, and b is an enlarged explanatory view of a Y portion of a.

FIG. 3 is an explanatory view of the groove portion of FIG. 2 as viewed in the welding direction, where a is normal and b is foreign matter on the groove surface.

FIG. 4 is a flowchart illustrating an operation in the embodiment of the present invention.

FIG. 5 is a flowchart illustrating an operation in the embodiment of the present invention.

FIG. 6 is a flowchart illustrating an operation according to the exemplary embodiment of the present invention.

FIG. 7 is a flowchart illustrating an operation according to the exemplary embodiment of the present invention.

FIG. 8 is a flowchart illustrating an operation according to the exemplary embodiment of the present invention.

FIG. 9 is a flowchart illustrating an operation according to the exemplary embodiment of the present invention.

[Explanation of symbols]

1: Automatic welding device 2: Robot body
3: Welding torch 4: Workpiece 5: Welding power source
6: Robot control device 7: Arithmetic processing device 8: Storage device 9: Robot main body control device 10: External control device 11: Input device 12: Robot operation calculation unit 13: Route gap calculation unit 14: Gap sensing retry calculation unit 15: Skip calculation unit 16: Teaching program storage unit 17: Gap sensing operation storage unit 18: Gap allowable value storage unit 19: Gap sensing retry setting storage unit 20: Primary storage unit 21: Gap sensing detection control unit 22: Welding power supply control unit 23 : Groove root gap 24, 25: weld joint forming member 26: backing material 27: groove 28: foreign material A: welding start side position B: welding end side position X: arrow indicating welding direction

Claims (2)

[Claims] 1. A root gap of a welded joint is sensed, and when the detected value is outside an allowable range, sensing is performed again at a position separated from the sensing position by a predetermined distance in the direction of the welded joint of the welded joint. If the detected value is outside the allowable range, the method moves to the next welded joint, which is a position detecting method in an automatic welding device. 2. The position detecting method in an automatic welding device according to claim 1, wherein the re-sensing is repeated a predetermined number of times.