JPH0691370A - Restarting method for welding robot - Google Patents

Abstract

PURPOSE:To provide the restarting method of the welding robot capable of restarting without causing weld defects even after robot stopping due to arc running out, etc. CONSTITUTION:The restarting method of the welding robot contains a process to detect the welding stop position and store the position, a process to restart and move the robot to the welding stop position, a process to restart welding after arrival on the welding stop position, a process to retreat a welding gun by the specified distance along a weld line at the faster speed than the ordinary welding speed after welding is restarted and a process to move the welding gun at the ordinary welding speed after the welding gun is retreated by the specified distance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for restarting a welding robot. More specifically, the present invention relates to a method for restarting a welding robot that can restart the welding robot without causing defective welding.

[0002]

2. Description of the Related Art Conventionally, in an arc welding robot, when the robot stops due to an arc break error or the like, the robot performs necessary repairs at the stop position or retracts the robot to a predetermined position to perform the necessary repairs. After returning to the stop position, the robot is restarted to perform arc welding (see FIG. 6). In addition, in FIG. 6, the dotted line indicates the evacuation route of the robot, and the solid line indicates the route when the robot is restarted.

However, when the robot is restarted by such a restarting method and welding is performed, there is a time lag between the detection of the arc breakage and the like by the sensor and the stop of the robot. As shown in FIG. 7, a portion D where welding is incomplete is formed between the welding bead 11 before the occurrence of the arc break and the welding bead 12 after the restart of the welding from the detection position of the break or the like to the stop position of the robot. Occur. That is, in the conventional method, the above-mentioned incompletely welded portion D remains as a welding defect. For this reason,
Conventionally, repair welding is performed by manual welding after automatic welding by a robot to remove this defect.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. Even after the robot is stopped due to an arc break or the like, no restart occurs without causing a welding defect. It is an object of the present invention to provide a method for restarting a welding robot to be obtained.

[0005]

A method for restarting a welding robot according to the present invention includes a procedure for detecting a welding stop position and storing the position, and a procedure for restarting the robot and moving the robot to the welding stop position. And, after reaching the welding stop position, restarting the welding, and after restarting the welding, retracting the welding gun at a speed faster than the normal welding speed by a predetermined distance along the welding line, and the welding gun. The procedure includes moving the welding gun at a normal welding speed after retracting the welding gun by a predetermined distance.

In the method for restarting a welding robot according to the present invention, it is preferable to add a procedure for retracting the stopped robot to a predetermined position when the robot stops.

In the welding robot restarting method of the present invention, it is preferable that the predetermined distance is calculated by the following equation. L = (v√i) / 20, where: L: retreat distance of welding gun (mm) v: normal welding speed (mm / sec) i: welding current (A)

Further, in the method for restarting a welding robot according to the present invention, it is preferable that the speed higher than the normal welding speed is in the range of 140 mm / sec to 160 mm / sec in linear velocity.

[0009]

In the method of restarting the welding robot according to the present invention, after the welding gun is moved to the welding stop position and the welding is restarted, the welding gun is retracted at a speed faster than the normal welding speed by a predetermined distance along the welding line. Since the welding is carried out at a normal welding speed, the desired welding is also performed on the incompletely welded portion between the position where the arc break or the like is detected and the position where the robot stops. Therefore, the welding robot can be restarted without causing a welding defect.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the accompanying drawings, but the present invention is not limited to such embodiments.

FIG. 1 is an overall schematic view of an arc welding robot according to the present invention, FIG. 2 is an explanatory view of a restarting method of the welding robot of the present invention, and FIG. 3 is obtained by the restarting method of the welding robot of the present invention. 4 to 5 are schematic views of the welding bead, and FIGS. 4 to 5 are flowcharts related to the method for restarting the welding robot of the present invention. In the figure, 1 is an operation panel, 2 is a robot controller, 3 is a welding power source, 4 is an arc welding robot main body, 5 is a welding bead before the occurrence of arc breakage, 6 is a welding bead after welding is restarted, and W is a work. Further, in FIG. 2, the dotted line indicates the retreat path of the robot, and the solid line indicates the path when the robot is restarted.

The operation panel 1, the robot controller 2, the welding power source 3 and the arc welding robot main body 4 in the arc welding robot according to the present invention, the overall construction of which is schematically shown in FIG. What is used for the arc welding robot is preferably used. Therefore, detailed description of the configuration is omitted.

Next, a method of restarting the arc welding robot thus configured will be described with reference to the explanatory view of FIG. 2 and the flow charts shown in FIGS. 4 to 5.

Step 1: When an arc break is detected by a detector (not shown), its position is stored in the memory 21 of the robot controller 2.

Step 2: It is judged whether or not the robot should be retracted.

Step 3: If it is determined to retract the robot, the robot is manually retracted to a predetermined position.

Step 4: If it is determined that the robot is not retracted, then it is determined whether or not to restart the robot. In the case of retracting the robot, this determination is made after retracting the robot. If it is determined that the robot will be restarted, the process proceeds to the next step.

Step 5: The return amount (backward distance) from the position where the arc break error is detected is calculated. This return amount (backward distance) is calculated by the following formula. However, when the value obtained by the following formula exceeds 10 mm, it is set to 10 mm. L = (v√i) / 20, where: L: retreat distance of welding gun (mm) v: normal welding speed (mm / sec) i: welding current (A)

Step 6: The robot is restarted and moved to the position where the arc break error is detected. In this case, the moving speed is preferably slower than the normal moving speed. This is so that the robot can be stopped immediately when there is an obstacle or the like in the movement route.

Step 7: When the position where the arc break error is detected is reached, welding is restarted.

Step 8: The welding gun is quickly retracted by the calculated return amount. The reason for the rapid retreat is that if the retreat is performed at a normal speed, the amount of welding becomes excessive and a proper weld bead cannot be obtained. The retreat speed at this time is specifically about 10 times the normal welding speed (14 at linear speed).
0 mm / sec to 160 mm / sec).

Step 9: After the welding gun retracts by a predetermined distance, welding is performed to the initial target position at a normal welding speed.

Step 10: When the initial target position is reached, welding is completed.

FIG. 3 is a schematic view of the weld bead thus obtained. As shown in FIG. 3, between the weld bead 5 before the occurrence of arc break and the weld bead 6 after the restart of welding,
There are no imperfections in welding as in the past.

Although the present invention has been described above by taking the arc welding robot as an example, the application of the present invention is not limited to the arc welding robot, but can be suitably applied to various welding robots.

[0026]

As described above, according to the present invention,
Even if the robot stops due to an arc break or the like, the welding robot can be restarted without causing a welding defect. Therefore, repair welding by manual welding after automatic welding is unnecessary, and work efficiency can be improved.

[Brief description of drawings]

FIG. 1 is an overall schematic view of an arc welding robot according to the present invention.

FIG. 2 is an explanatory diagram of a restarting method for the welding robot according to the present invention.

FIG. 3 is a schematic view of a weld bead obtained by the method of the present invention.

FIG. 4 is part of a flow chart relating to the method of the invention.

FIG. 5 is part of a flow chart relating to the method of the invention.

FIG. 6 is an explanatory diagram of a conventional welding robot restart method.

FIG. 7 is a schematic view of a welding bead obtained by a conventional method.

[Explanation of symbols]

 1 Operation panel 2 Robot controller 3 Welding power source 4 Arc welding robot main body 5 Weld bead before arc break 6 Weld bead after welding restart W Work

Claims (5)

[Claims] 1. A procedure of detecting a welding stop position and storing the position, a procedure of restarting a robot to move it to the welding stop position, and a procedure of restarting welding after reaching the welding stop position. After restarting the welding, the procedure of retracting the welding gun along the welding line by a predetermined distance at a speed faster than the normal welding speed, and after retracting the welding gun by a predetermined distance, the welding gun at the normal welding speed. And a step of moving the welding robot, the method of restarting a welding robot. 2. The method of restarting a welding robot according to claim 1, further comprising a step of retracting the stopped robot to a predetermined position when the robot is stopped. starting method. 3. The method of restarting a welding robot according to claim 1, wherein the predetermined distance is calculated by the following formula. L = (v√i) / 20, where: L: retreat distance of welding gun (mm) v: normal welding speed (mm / sec) i: welding current (A) 4. The method for restarting a welding robot according to claim 1, wherein the speed higher than the normal welding speed is in the range of 140 mm / sec to 160 mm / sec in linear velocity. 5. The method for restarting a welding robot according to claim 1, 2, 3 or 4, wherein the welding robot is an arc welding robot.