JPS60152374A - Welding position detecting method - Google Patents

Abstract

PURPOSE:To improve an efficiency by installing a stylus to a welding torch, deriving its position and direction, moving backward by a prescried quantity the stylus which has contacted to the first work, and thereafter, making it execute a sensing in the direction of the second work, and detecting a welding position. CONSTITUTION:A welding torch T is moved to a rough teaching point O, and a stylus 3 is advanced by an air cylinder 1 until it coincides with the tip of a welding wire W. In a state that a voltage of a detecting power source 51 is applied between a work member UV and the contact needle 3 by a signal of a robot controller 6, a vector calculation of a position and a direction of the torch T is executed based on an installed state of the stylus 3. With respect to this calculated value, the stylus 3 is brought to sensing in the direction of the first work U, moved backwrd by a prescribed quantity from a contact point to the work U, and thereafter, brought to sensing in the direction of the second work V. From a contact point to the second work V, the stylus 3 is moved backward by a relay 55 and stopped. Therefore, the sensing operation is reduced and the efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention describes the welding torch in the first place. The present invention relates to a welding position detection method for positioning a second work member at a corner portion.

Conventional welding position detection methods of this type include the following.

(1) Detection method using welding wire As shown in Fig. 1, this detection method uses the welding wire W itself as a sensor, disconnects the welding power supply circuit at J3 before welding, and connects another detection power supply circuit. . In this case, the first. Second work member U.

The V side earth line is a common line, and the detection power supply circuit is connected to the welding wire W. And when detecting, welding wire W
In this method, the contact point is brought into contact with the work member U or V, and the contact is electrically detected.

(2) Detection method using a proximity switch In this detection method, a commercially available proximity switch is used for welding 1, and the welding position is detected using this proximity switch in the same manner as in the previous case.

In method (1), the protrusion length Ewj of the welding wire W differs before and after welding, so if left as is, the detection accuracy will vary. Therefore, the protrusion length of the welding wire W needs to be equal to the standard protrusion length EO.

Therefore, for example, it is necessary to cut the 8-junction wire W, control wire feed on a standard gauge, etc. every time for each welding location. Therefore, work efficiency is extremely poor. Zarani (1)
In this method, since the sensor has no directionality, it is necessary to teach all steps of the operation (direction and procedure) at the sensing location. 1', that is, No. 1 in FIG.
When welding the corner portions of the second work members U and ■, the first work member U and the second work member V are taught through the steps of ■, ■, ■, and ■ shown by broken lines. , errors ΔU and Δ■ during the teaching are detected, respectively. After calculating and correcting the teaching data by the detected error, it is necessary to guide the welding torch T to the corner portion in step (3) and start welding. Therefore, at least steps (■) to (■) are required.

Furthermore, in method (2), the size of the sensor itself becomes large, making it difficult to approach the corner portion, which is a narrow area, and making it unsuitable for welding to such a location.

Therefore, methods (1) and (2) above are extremely inconvenient when intermittent welding is repeatedly performed in a short period of time, such as tack welding, in a narrow area, and there are many problems in terms of work efficiency and cost. Ta.

The present invention was made based on these circumstances,
The purpose is to provide a welding position detection method that can perform welding efficiently and at low cost even when tack welding or the like is performed in a narrow area.

In order to achieve the above object, the present invention is characterized by the following configuration. That is, a sensing stylus is attached to the side of the welding I-ch, and the position and direction of the torch is determined based on the state of attachment of this stylus to the welding torch. Then, the torch is sensed in the direction of the first workpiece member according to the position and direction of the torch, and is moved back by a certain amount from the position where the stylus contacts the surface of the first workpiece member. Sensing is performed in the direction of the second workpiece member. The present invention is characterized in that the position where the stylus contacts the second workpiece member is set as the welding position.

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

FIG. 2 is a diagram showing the configuration of an apparatus for carrying out the method of the present invention, and FIG. 3 is a view taken along arrows 1--2 in FIG. The welding torch T is attached to the wrist of the arc welding robot. An air cylinder 1 is attached to the side surface of the welding torch T, and the base end of a stylus 3 is connected to the tip of a rod 2 in the air cylinder 1. The tip of the stylus 3 is attached to a guide tube 4 installed on the side wall below the welding torch.
It is configured to extend slidably through the inside of the welding wire W to near the tip of the welding wire W.

Reference numeral 5 denotes a sensor controller, which includes a detection power source 51 and a relay contact 52. Short circuit detector 53. Short circuit detection relay 54. It has a built-in sensor activation relay 55, etc. Above detector'&5
1 is applied between the stylus 3 and the workpieces UU and V through the relay contact 52. Further, the short circuit detector 53 detects a short circuit current that flows when the stylus 3 comes into contact with the workpiece U or V, and operates a short circuit detection relay 54. Note that the contact signal of the relay 54 is supplied to the robot controller 1-roller 6. Furthermore, the sensor activation relay 55 operates based on a control signal from the robot controller 6 to turn the relay contact 52 on and off.

The robot controller 1 to the roller 6 start operating based on an external command, and receive signals from the limit switch 11, 12 installed in the air cylinder 1 for detecting the forward/backward position of the cylinder, the short circuit detection relay 54, etc. In response to this, a control signal is given to the above-mentioned C/S start relay 55 and the cylinder drive solenoid valve 7.

The cylinder drive solenoid valve 7 operates based on a control signal from the robot controller 6, and the cylinder drive solenoid valve 7 operates based on a control signal from the robot controller 6.
, 7B, air is introduced into and taken out from the air outlet ports IA and IB of the air cylinder 1.

Next, a welding position detection method using the present apparatus configured as described above will be explained with appropriate reference to FIGS. M4 and FIG.

First, welding 1.--dT is moved to the rough teeing point near the tack welding point indicated by [0] in FIG. Next, a control signal from the robot controller 6 is applied to the cylinder drive solenoid 7 to operate the solenoid 7,
Air cylinder 1 is moved forward. This forward movement is confirmed by the limit switch 11. In this way, the stylus 3 moves forward and stops when its tip matches the tip of the welding wire W.

Next, the sensor activation relay 55 is activated by a control signal from the robot 1-controller 6, and the relay contact 52 is closed. As a result, from the detection power supply 51 to the relay contact 52
The stylus 3 and the workpiece U are connected through the stylus 3 and the workpiece U.

(2) Power is applied and supplied between. In this state, the position and direction of the welding torch T and the attachment of the stylus 3 attached to the side surface of the torch T are determined by vector calculation from the data of each axis of the robot based on the state.

Next, the welding torch T is moved in a specific angular direction, that is, in a direction having an angle of 10 with respect to the calculated vector value, and a sensing operation as step [1] is performed. When the stylus 3 contacts the first work member U and a short circuit occurs and a detection signal is detected by the short circuit detector 53, the detection relay 54 is turned on and the contact signal is transmitted to the robot controller 1-〇-. La 6
, the movement of the welding torch T by the robot in the direction of the first workpiece member is stopped.

Next, weld] - T to the specified amount x, for example, 0.5 to 2.0
It is moved back by about m in the opposite direction as step [2]. In other words, the welding torch T is set so that the stylus 3 does not rub against the first workpiece U during the next operation and is not deformed, and within the positioning error range that does not affect welding.
move.

Next, a sensing operation as step [3] is performed in a direction having an angle of +θ with respect to the vector calculation value.

When the stylus 3 contacts the second workpiece V, a detection signal is detected by the short circuit detector 53 and input to the robot controller 6. Therefore, the robots 1 to 1 stop moving the welding torch T toward the second workpiece member. Furthermore, the relay 55 returns to normal and the relay contact 52 opens, so the sensor detection power source 51 is cut off. Also, since the control signal to the solenoid valve 7 is cut off, the stylus 3 moves back. This backward movement is confirmed by the limit switch 12.

The above position is set as the welding start position, and the teaching data of the welding crater position ahead is corrected by the amount of deviation from the teaching point 1~.

With the above operation, the sensing operation for one tack welding location is completed. Therefore, arc welding is started and tack welding is performed while performing linear interpolation.

Note that the present invention is not limited to the above embodiments. For example, in the embodiments described above, the present invention was applied to arc welding robots l~, but it can also be applied to other automatic welding machines or sealant coating robots.

As explained above, according to the present invention, the welding torch is given directionality by the stylus attached to the side of the welding torch, and the vector is determined, and the sensing operation is performed by software. The teaching work for the sensing operation itself can be omitted, and the amount of back movement from the sensing position in one direction of the sensing operation in two directions can be determined in advance, and the sensing operation can be performed from that position in the second direction. As a result, the welding position (corner) can be easily found within a range that does not interfere with welding, and the number of sensing operation steps is reduced.
Improve efficiency and reduce costs.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing a conventional welding position detection method, and FIGS. 2 to 5 are diagrams showing an embodiment of the method of the present invention.
The figure is a diagram showing the configuration of the device used for implementation, FIG. 3 is a view taken along the ■-■ arrow in FIG. 2, and FIG. 4 is an explanatory diagram of sensing operation.
FIG. 5 is a flowchart for explaining the operation. DESCRIPTION OF SYMBOLS 1...Air cylinder, 2...Rod, 3...Stylus, 4...Kite tube, 5...Sensor controller, 5
1... High detection power supply, 52... Relay contact, 53...
Short circuit detector, 54... Short circuit detection relay, 55... Sensor activation relay, 6... Robot 1 to controller, 7
...Air cylinder drive solenoid valve, ■...
Welding torch, W...welding line. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 2 Figure 3 Otsu 1 Figure 4

Claims (1)

[Claims] A stylus for sensing is attached to the side of the weld (.--), and the attachment of this stylus to the weld 1-- is determined based on the condition and the position and direction of the weld 1, The torch is sensed in the direction of the first workpiece, the stylus is moved back a certain amount from the position where it contacts the surface of the first workpiece, and the torch is moved back from that position to the second workpiece.
A method for detecting a welding position, characterized in that sensing is performed in the direction of a second workpiece member, and the position where the stylus contacts the second workpiece member is recognized as the welding position.