JPH06126455A - Method and device for controlling arc welding robot - Google Patents

Abstract

PURPOSE:To prevent deterioration of the welding quality by operating the robot under a specified condition when an alarm is sounded without generating an arc by the arc welding robot. CONSTITUTION:In welding by the arc welding robot, the robot is moved up to a welding starting point, an arc generation demand S1 is outputted to a welding machine and then, when the alarm is inputted from the welding machine side without generating (S2) the arc, the robot is operated (S4a) while the arc generation demand is outputted under lower conditions than welding main condition in the weld line direction in the target welding section, an arc generation confirmation signal is inputted from the welding machine side, then, the robot is moved (S7), in a state with the arc generated up to the welding starting point and the robot is continued to operate in the taught section under the set welding conditions from the welding starting point. Consequently, the deterioration in the welding quality can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for controlling an arc welding robot when the arc generation is unsuccessful.

[0002]

2. Description of the Related Art For example, in an industrial robot that performs arc welding work, when an arc is not generated at the welding start point and an alarm is generated from the welding machine side, the work is stopped,
We had to replace it with a new work piece and perform welding work from the beginning.
Alternatively, the robot is shifted a certain distance from the welding start point, and the arc generation request is again issued to the welding machine under the set welding conditions.

[0003]

The former is a means for preventing a defective work from being produced, but it was necessary for an operator to perform welding work on a work in which no arc was generated.
In the latter case, an arc is generated under welding conditions set at a point other than the welding start point, and the section returns to the welding start point,
The welding quality was impaired because welding was performed twice. Furthermore, when an arc does not occur due to an insulator or the like attached to the tip of the welding wire, the arc cannot be generated by the above method. Therefore,
It is an object of the present invention to provide a control method and device that do not require the operator's trouble and do not impair the welding quality.

[0004]

According to a first aspect of the present invention, when an arc is not generated and an alarm is output from the welder side, the arc condition is lower than the welding condition set for the welder side. While outputting the generation request, move in the welding line direction,
When the arc is generated, the robot is moved to the welding start point and the operation is started from the welding start point under the set welding conditions. According to a second aspect of the present invention, when an alarm is output from the welding machine side without generating an arc, the welding torch is weaved to bring the tip of the wire into contact with the base material, and then the arc is generated. At this point, the robot is moved to the welding start point and the operation is automatically started from the welding start point under the set welding conditions. A third invention of the present invention is an apparatus for carrying out the first invention. A fourth invention of the present invention is an apparatus for carrying out the second invention. A fifth invention of the present invention is an apparatus which can be selectively implemented from the first invention and the second invention.

[0005]

According to the first aspect of the present invention, the arc is generated easily under the condition that the arc generation request is output under the condition lower than the welding condition, and the arc is easily generated. Even when an arc is generated, since the condition is lower than the welding condition, there is little influence on the original welded portion and welding can be performed without lowering the welding quality. According to the second invention, the insulator or the like attached to the torch is removed by coming into contact with the base material, so that an arc is easily generated. The method of the first invention can be automatically realized by the third invention. The method of the second invention can be automatically realized by the fourth invention. According to the fourth invention, the method of the first invention and the method of the second invention can be selected and automatically realized.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A controller for a welding robot will be described below as an embodiment of the present invention with reference to the drawings. FIG. 1 is a block diagram showing an example of a system for carrying out the present method. 1 is a manual operation command unit, 2 is a position teaching unit, 3 is an operation start command unit, 4 is a welding machine, 5 is position memory. Reference numeral 6 is an alarm monitoring unit, 7 is a robot operation control unit, and 8 is a robot drive unit. The robot operation control unit 7 welds the inside of the taught welding section in the welding line direction under a condition lower than the present condition, or means for operating the robot while outputting the arc generation request, or weaving the torch at the welding start point. A means for bringing the wire into surface contact with the base material, or both, can be incorporated to selectively implement the two. Further, when the former method fails, the latter method may be automatically used. FIG. 2 shows positions of teaching points (P1 and P2) and welding start point positions (P
1) and the position (PA) at which the robot receives the arc generation confirmation signal.

The operation of the present invention will be described with reference to the flowchart of the present invention shown in FIG. P1 is a welding start point and P2 is a welding end point, which are stored in advance in the position storage unit in the position teaching unit. First, the welding robot moves to P1 and issues an arc generation request to the welding machine of FIG. 1 (S1). Next, it waits for a signal indicating success or failure of arc generation to enter the robot controller (S2). Next, when the arc is successfully generated, the robot starts welding and performs welding under the designated conditions toward the welding end point (S3).
Here, a case where A is selected when no arc occurs will be described. When no arc is generated, the welding machine starts moving a certain distance in the welding line direction while outputting a welding command to the welding machine under a condition lower than the set welding condition (S4).
a). The robot performs the same processing as S2 while moving (S5). If the arc generation confirmation signal from the welding machine is not received by the robot controller while the robot is moving for a certain distance, an alarm is generated (S6). Robot is in position P
When the arc generation confirmation signal from the welding machine is received at point A, the robot is moved to the welding start point P1 while the arc is being generated (S7) (see FIG. 2A). Specified welding is performed from the welding start point P1.

Next, a case where B is selected when an arc does not occur will be described. When no arc is generated, the weaving of the torch is started with the welding command output to the welder side under the set welding conditions (S4b). At this time, an insulator is attached to the tip of the wire, and an arc is unlikely to be generated by the usual method of contacting with the base material. By weaving the torch as shown in FIG. 4, the matching operation is carried out while the torch is in surface contact, so that the insulator can be removed. The robot performs the same process as S2 while weaving the torch (S5). While the robot is weaving the torch, if an arc generation confirmation signal from the welding machine does not enter the robot control unit, an alarm is generated (S6). When the robot receives the arc generation confirmation signal from the welding machine at the point of position PA, the robot is moved to the welding start point P1 with the arc being generated (S7) (see FIG. 2 (b)). Specified welding is performed from the welding start point P1.

[0007]

As described above, according to the present invention,
At the welding start point, when the arc does not occur, the arc is regenerated without relying on human labor, and in a state where the arc is generated under a condition lower than the set welding condition,
Since it returns to the welding start point, there is an effect that the welding quality is not impaired.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating a movement operation of the robot of the present invention.

FIG. 3 is a flowchart for explaining the present embodiment.

FIG. 4 is an explanatory diagram of a weaving operation of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kazuyo Yoshida, No. 2 Kurosaki Shiroishi, Yawatanishi-ku, Kitakyushu, Fukuoka Prefecture Yasukawa Electric Co., Ltd. No. Yasukawa Electric Co., Ltd.

Claims (5)

[Claims] 1. A method of controlling an arc welding robot, wherein the robot moves to a welding start point, outputs an arc generation request to a welding machine, and then receives an alarm from the welding machine side without generating an arc. In the case of welding in the taught welding section in the welding line direction, the robot is operated while the arc generation request is output under conditions lower than these conditions, and the welding start point is received after receiving the arc generation confirmation signal from the welding machine side. Control method for an arc welding robot, characterized in that the robot moves while the arc is generated up to and continues to operate between teaching points under the set welding conditions from the welding start point. 2. A control method for an arc welding robot, wherein the robot moves to a welding start point, outputs an arc generation request to the welding machine, and then receives an alarm from the welding machine side without generating an arc. In this case, weaving the torch at the welding start point, receiving the arc generation confirmation signal from the welder side, then moving to the welding start point with the arc generated, and teaching point under the welding conditions set from the welding start point. A method for controlling an arc welding robot, which is characterized by continuously operating for a period of time. 3. A control device for an arc welding robot, wherein the robot moves to a welding start point, outputs an arc generation request to the welding machine, and then receives an alarm from the welding machine side without generating an arc. In the case of welding in the welding section in the direction of the welding line, the means for operating the robot while outputting the arc generation request and the arc generation confirmation signal from the welding machine side during the operation are received. After that, the control device of the arc welding robot, characterized in that it comprises means for moving in a state where an arc is generated to a welding start point. 4. A control device for an arc welding robot, wherein the robot moves to a welding start point, outputs an arc generation request to the welding machine, and then receives an alarm from the welding machine side without generating an arc. In this case, if the weaving torch at the welding start point makes the wire come into surface contact with the base metal, and after the surface contact is made, the arc generation confirmation signal is received from the welder side, the arc is generated up to the welding start point. An apparatus for controlling an arc welding robot, comprising: a means for moving the robot in a state. 5. A control device for an arc welding robot, comprising: the means according to claim 3 and 4, and a means for selecting one of the means.