JPH11104831A - Device for controlling arc-welding robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unnecessitate changing work at upper and lower limit values if allowable range values are the same values even in the case of changing a welding condition command value by providing an RAM for storing the allowable range values and a CPU part for treating whether inputted monitoring objective welding current and voltage command values are within the upper and the lower limit values or not. SOLUTION: When a welding torch 7 is made to reach a prescribed weld starting point of a work 5 with a robot main body 4, a robot control device main body 1 executes a weld starting command to a welding electric source 3 through a communication control line L1 after transmitting the pre-stored regular welding condition and when an arc answer is returned from the welding electric source 3, the arc welding is executed at a pre-stored welding speed with the welding torch 7 along a prescribed welding corse of the work 5. Whether an actual welding value fetched from the outside during actual welding is within a range from a welding condition command value -an allowable lower limit value to the welding condition command value + an allowable upper limit value, or not, is judged and in the case that the actual welding value deviates from the allowable value, the driving information of the robot to the outside is displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for an arc welding robot in which a teaching playback robot and an arc welding machine are combined.

[0002]

2. Description of the Related Art The prior art has a configuration as described in Japanese Patent Application Laid-Open No. Hei 4-237565. That is, as shown in FIG. 8, a CPU circuit 100 and an external interface circuit 101 are provided, and a printer 103 is connected to the CPU circuit 100 via a print output interface 102.
Is connected. The measurement / display switching circuit 104 is used as a measurement / display switching means, and the limiter upper / lower limit selection adjustment circuit 10 is used.
5, limiter upper / lower limit adjuster 106, limiter selector 1
07 is a limiter upper / lower limit setting means, and the welding current detector 1
08 and the welding voltage detector 109, the actual welding conditions can be obtained and displayed on the display 110. With this configuration, the limiter upper / lower limit setting means can directly set the upper and lower limiter levels. The output result shown in FIG. 9 is printed, and whether the welding current and the welding voltage are within appropriate ranges is determined. Can be monitored. In FIG. 9, UL = 230A (ampere) in the second row, LL = 2
10A indicates the upper and lower limits of the set welding current monitoring range. 9 indicates that the welding current is to be monitored. In FIG. 9, 208 indicates that the value was below the lower limit level, and 233 in FIG. 9 indicates that the upper limit level was exceeded.

[0003]

However, in the above welding monitoring apparatus, since the upper and lower limits (permissible) of the welding current and the welding voltage to be controlled for the welding quality are designated by direct values, the welding conditions are not changed. If the command is changed in the middle, it cannot be used unless the upper and lower limits of the welding current and welding voltage to be subjected to the welding quality control are reset to direct values. In addition, since the arc unstable section immediately after the first arc start in one welding section is also monitored, erroneous detection is performed although the welding is not defective. Crater processing is performed at the end of one welding section. In this crater processing section, the welding condition command is reduced by about 50 A in welding current and 5 V in welding voltage from the main welding conditions. ,
In the conventional example, erroneous detection was performed. Furthermore, if a conventional arc welding condition monitoring device is used on an automatic welding line using a robot or the like, information such as the operating information of the robot that caused the welding failure at that time could not be obtained. There was a problem that it took too much time to grab the, and no quick measures could be taken.

The present invention has been made in view of the above-described problems of the prior art, and is directed to a controller for an arc welding robot using a teaching playback robot, which determines whether or not arc welding conditions are in an appropriate range. In the case of deviation from the above, it is possible to provide the information as to which teaching point during the operation of the robot the occurrence point is to the outside, so that the maintenance and management of the arc welding quality can be performed sufficiently, inexpensively, easily and quickly. It is an object of the present invention to provide a control device for an arc welding robot.

[0005]

According to a first aspect of the present invention, when a robot arm (welding torch) reaches a welding start point, a welding condition command and a welding start command are transmitted to a welding power source. A welding robot control device that issues a crater welding condition command and a welding end command to a welding power source when the robot arm (welding torch) reaches a welding end point. It has an external interface circuit with a welding power source for obtaining a voltage, an input means capable of inputting a permissible range value for the teaching welding condition command, and a RAM for storing the permissible range value. The robot controller is provided with a CPU for processing whether or not the welding current / voltage is within the upper / lower limit (allowable range) with respect to the command value. You have to have a condition monitoring function. Next, the second means of the present invention uses the structure of the first means, and when a condition range deviation state occurs during the monitoring of arc welding conditions,
Information notification for displaying the upper and lower limit values of welding conditions, the number of deviations, and operation information (job No., program No., step No., etc.) of the robot at the time of crater welding, which is the end of one welding process, and the number of deviations. It is a continuation of the means. Next, the third means of the present invention uses the configuration of the first means to sort the operating information of the robot at the time of deviating from the permissible range value in the arc welding condition monitoring function in a time-series manner.
The data is stored in the AM, and the data is retained even after the main current is turned off, so that the operator can obtain the operating information of the robot via the information notifying means whenever necessary. . Next, the fourth means of the present invention can use the configuration of the first means to set a monitoring start delay time immediately after the start of welding in order to exclude a section where the welding condition is unstable from the welding condition monitoring target section. It has a robot controller main body that delays the start of welding condition monitoring by a set time. The external interface circuit is a communication control unit for exchanging control signals with the welding power source, and is controlled by a CPU unit on the welding power source side via a bus. In addition, this external interface circuit is configured to obtain the actual welding current value and actual welding voltage value to perform welding control, and these actual values are input to the robot controller main unit through communication or directly from the welding power supply. It is not necessary to add a special device for detecting the welding current / voltage.

[0006]

As described above, according to the first means of the present invention, the teaching data for specifying the welding condition monitoring range is not a fixed direct value but an upper and lower limit (allowable value) for the welding condition command value. Is not affected by the change of the welding condition command value.

Further, according to the second means of the present invention, if the arc welding condition monitoring range is deviated, the robot job No., program No., step No.
The deviation information, such as the number of deviations in the section and the condition monitoring range value, can be transmitted to information notification means such as an external teach pendant or a personal computer.

In the third means of the present invention, the deviation information is stored in a memory in a time-series manner, so that the operator can obtain the time-series deviation information data by a TP or an external personal computer when necessary. The tendency of the deviation phenomenon of the arc welding condition can be easily grasped.

According to the fourth means of the present invention, an arc unstable area at the time of arc start can be excluded from the target of monitoring the arc welding condition, so that erroneous detection of the arc welding condition monitoring can be prevented, and the welding quality can be improved. Maintenance and management can be performed easily and sufficiently.

An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, a robot control device main body 1 is connected to a teaching TP2 by a communication line control line L1, and is connected to a welding power source 3 by a communication control line L2. The operator moves the robot main body 4 minutely while directly watching the welding torch 7 disposed at the control reference point of the industrial robot while operating the TP2, and teaches the robot in order of the work to be performed. The teaching data is stored in the RAM 8 of FIG. The operator fixes the work 5 to be welded to the base material 6 and
Is operated to move the welding torch 7 to the welding start point a in FIG. 3, and the teaching position data and that the point is the welding start point;
In addition, a one-key registration of a welding condition command (welding current value / welding voltage value) and a welding start command (arc-on processing sequence) is performed using the welding registration key 2a on TP2. Next, the welding torch 7 is moved by the robot body 4 to the welding end point b in FIG. 3, and the teaching position data and that point is the welding end point, and the crater welding condition command (welding current value / welding voltage) Value), welding end command (arc-off sequence) to TP
One key registration is performed with the welding end key 2f on the second key. The taught program is stored in the RAM 8 of FIG. 2 by the CPU unit, and the automatic welding system of FIG. 1 is automatically operated by the registered program that has been taught. The content of the welding operation is as follows. The robot main body 4 moves the welding torch 7 to a predetermined welding start position a of the work 5 at a welding start point a in FIG.
When the robot reaches the point, the robot controller 1
After the main welding conditions (welding current value / welding voltage value) stored in advance have been transmitted via the communication control line L2 to the welding power source 3, the welding start command is executed and an arc answer is returned from the welding power source 3. Along the predetermined welding path of the workpiece 5,
Arc welding is performed at a welding speed stored in advance. Thereafter, when the welding torch 7 reaches the welding end point b in FIG. 3, the crater welding conditions (welding current value
(The welding voltage value) is transmitted, the robot is stopped, and a welding end command for performing the crater process is executed. Thereafter, a wire stick check is performed. If there is no fusion of the wire 10 to the workpiece 5, the next teaching point is performed. Move to.

Next, the liquid crystal display screen of TP2 shown in FIG. 4 will be described. When the operator wants to use the arc welding condition monitoring function, he or she selects at least one of the welding current or the welding voltage as an arc welding monitoring target by operating the key of TP2 while looking at the screen of FIG. Enter the upper and lower limit (allowable value) for the value as a direct value. In addition, after receiving the arc answer after the welding start command processing, a delay time 2 for delaying the start of the arc welding monitoring.
C is set, and the general-purpose output of the robot is allocated and used to notify the outside that a phenomenon outside the arc welding monitoring range has occurred. 2d can be set.
These setting data are stored and held in the RAM 8. In FIG. 2, when the operation is started from the outside, RA
The robot body 4 carries the welding torch 7 to a predetermined welding start position of the workpiece 5 (point a in FIG. 3) in accordance with the registered program stored in the memory M8. Next,
When the welding torch 7 reaches the welding start point a, the CPU first transmits a welding condition command from the communication control unit 11 to the communication control unit 12 of the welding power source 3 via the communication control line L2.
The part 13 receives the main welding condition. (The description of the specifications of the communication protocol and the data format is omitted.) Next, when a welding start command is transmitted from the robot controller main body 1 to the welding power source 3 through the same route, the CPU unit in the welding power source 3 13 drives a driver 14 by a control circuit (not shown) to generate welding energy, which is transmitted from the + output L3 of the welding power source to the wire 10 as a consumable electrode, and the wire 10 is sent to the wire feeder 15 in FIG. To work 5. This work 5 is the output L of the welding power source 3
When the wire 10 is connected to the work 4 and the wire 10 comes into contact with the work 5, electric energy of about several hundred amperes and about 20 volts flows from the tip of the wire to the work, so that a part of the metal of the wire 10 and the work 5 starts to be melted. It will be a start.
When the arc starts, the welding power source 3 returns an arc answer to the robot controller main body 1 by the communication control unit 12 via the communication control line L2. Upon receipt of this arc answer, the robot controller main body 1 moves the robot main body 4 and moves the welding torch 7 along a predetermined welding path of the workpiece 5.
It is moved at a welding speed stored in advance. And
During welding, the welding power source 3 performs the actual welding current value through the DCCT (Hall element) 16 and the A / D converter 17 and the voltage across the bleeder resistor 18 via the A / D converter 19 to perform welding control. Get the voltage value. The obtained data is stored, averaged for each sampling time, and transmitted from the communication control unit 12 to the robot control device main body 1 via the communication control line L2.

Here, after receiving the arc answer, the robot controller main body 1 according to the information set on the TP liquid crystal display screen of FIG. The difference between the voltage value and the pre-teaching main welding condition previously instructed to the welding power source 3 is calculated, and it is determined whether or not the difference is within a set allowable upper and lower limit value. . If the difference is outside the allowable range, the welding operation is continued. The general-purpose output assigned in 2d is operated to notify the outside by hardware. When one welding section at this time ends, that is, when the welding torch 7 reaches the welding end point b, a welding condition monitoring screen shown in FIG. 5 is generated and stored in the RAM 8 and via the personal computer communication control unit 20. The screen information is transmitted to the external personal computer 21 for information transmission.

Further, when the welding torch 7 reaches the welding end point b in FIG. 3, the robot controller 1 terminates the monitoring of the arc welding conditions, and transmits the crater welding conditions stored in advance to the welding power source 3, Next, after a welding end command is executed, a wire stick check (known) is performed. If there is no fusion of the wire 10 to the workpiece 5, the wire 10 moves to the next teaching point. In FIG. 6, the actual welding current value and the actual welding voltage value are transmitted from the welding power source 3 to the robot controller main body 1 at each of the sampling cycle points t0, t1,.
Will be sent to Since the data at the sampling period point t0, which is the first data, is an unstable portion immediately after the start of welding, it is ignored and the check is started from the data after t1. Here, the main welding conditions are defined as a welding current command value A and a welding voltage command value V.
Then, the allowable welding range can be expressed as A-lower limit value ≦ actual welding current value ≦ A + higher limit value V−lower limit value ≦ actual welding voltage value ≦ V + higher limit value. In FIG. 6, the obtained actual welding current value is represented by a black mark and the actual welding voltage value is represented by a Δ mark.
In addition, for "NG", A1, A2,... For the welding current and V for the welding voltage
1, V2,... In the example of FIG. 6, since the data at the sampling period points t1 and t2 are within the allowable range, “O
K ”, at the sampling cycle point t3, the actual welding current value is A +
Since the upper limit of the allowable value ≦ the actual welding current value, it was expressed as “A1”. Hereinafter, it is determined whether or not the obtained data is within the allowable range for each sampling cycle, and if the obtained data deviates, the data is accumulated until one welding process is completed. However, the data at the sampling cycle point tn in FIG. 6 or the sampling cycle point tm in FIG. 7 at the crater welding point is ignored and not monitored. In the case of FIG. 6, the actual welding current value ≦ A−the lower limit of the permissible value is A2, A3.
A: A1 with the upper limit of allowable value ≤ actual welding current value is 1 in A1 Actual welding voltage value ≤ V-1 with lower allowable value of V1 V + upper limit of allowable value ≤ 0 with actual welding voltage value . FIG. 5 shows such information expressed on the screen of the TP2 or the personal computer 21.

FIG. 5 shows a screen generated when the arc welding condition monitoring function is activated. Only one screen is generated for each welding process in which the arc welding condition monitoring function is activated. 12 in FIG.
Reference numeral 25 indicates that the entire screen has 25 screens, and the currently displayed page is the twelfth screen. FIG.
“Job.11” indicates the job number 11. A job is composed of at least one or more programs. "Prg.123" is a program number 123, which constitutes "Job.11", and "Step.045" of the program is the fourth.
This is the fifth step. For example, this indicates that the monitoring operation has been performed in one welding process after the welding start point a in FIG. That is, the step displayed in FIG. 5 is the welding start point. In FIG. 5, the welding current has an upper limit of +20 A (ampere) and a lower limit of −20 A with respect to the welding current command value.
20A. On the other hand, the welding voltage indicates that the upper limit value is +3.0 V (volt) and the lower limit value is −2.5 V with respect to the welding voltage command value. In the screen of FIG. 5, when the main welding conditions are a welding current command value A and a welding voltage command value V, A + 20 ≦ the actual welding current value is one sampling count. The actual welding current value ≦ A−20 is the two sampling counts V + 3.0 ≦ real. The welding voltage value is 0 sampling times. The actual welding voltage value ≦ V−2.5 indicates that the number of sampling times is 1.

Next, in the case of this embodiment, 99 screens can be created and stored. Also, 99
If all screens are generated and another screen is added, L
In the form of an IFO and having a link structure, the latest screen added to the oldest screen in chronological order is overwritten, the screen page is changed from 01/99 to 99/99,
Other existing screens are screen pages in which n of n / 99 is subtracted by one. That is, the smaller the value of n, the more past data. This data is R
Since the data is stored in the AM 8 and is backed up by the battery 22, the data is retained even after the main power is turned off.

Next, when the welding torch 7 reaches the welding start point a in FIG. 7, a procedure for starting welding is performed between the robot controller main body 1 and the welding power source 3, and at the end of the procedure, the robot controller starts. Arc answer is welding power source 3 to main body 1
Sent from The robot controller main unit 1 follows the information set on the liquid crystal display screen of TP2 in FIG. 4 and receives the arc answer in FIG.
The start of the monitoring of the arc welding conditions is delayed by 2C), and after the delay time T elapses, the welding which has been previously taught with respect to the actual welding current value and the actual welding voltage value sent from the welding power source 3 at each sampling time. The difference from the condition command value is calculated, and the CPU 9 starts determining whether or not the difference is within the allowable range.

[0017]

According to the first aspect of the present invention, the welding condition monitoring range is not a direct value, but an allowable range value can be designated as an upper and lower limit value for the welding condition command value. If the permissible range values are the same even if they are changed, it is unnecessary to change the upper and lower limits.

Further, according to the second means of the present invention, when the robot deviates from the arc welding condition monitoring range, the job No., program No., step No.
The deviation information such as the number of deviations in the section and the condition monitoring range value is transmitted to the TP or an external personal computer and displayed on a screen to notify the operator. Further, according to the third means of the present invention, the deviation information can be stored in the memory in a time-series manner, and the contents of the memory can be stored and retained by the backup battery even when the main power is turned off.

Further, according to the fourth means of the present invention, an erroneous detection can be prevented because the unstable area of the arc at the time of the arc start can be excluded from the monitoring target of the arc welding condition.

As described above, when the operator needs,
Since deviation information, which is time-series data, can be obtained from P or an external personal computer, the tendency of deviation phenomena can be easily grasped, and maintenance and management of welding quality can be performed easily and sufficiently.

Further, by giving a welding condition command or the like and providing a master robot control device having a welding power source as a slave with an arc welding condition monitoring function, the actual welding current value and actual welding current value can be used as the arc welding condition data. By using the data of the welding power source that is required and generated in controlling the welding voltage value, an inexpensive and accurate arc welding condition monitoring function can be realized.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a control device of an arc welding robot according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram showing a control device of the arc welding robot.

FIG. 3 is a perspective view of a main part showing one welding process.

FIG. 4 is a partial plan view of a teach pendant (TP) showing a screen for setting welding condition monitoring.

FIG. 5 is an output screen view of a welding condition monitoring result.

FIG. 6 is a timing chart showing a procedure for monitoring welding conditions in one welding process.

FIG. 7 is a timing chart showing a monitoring start delay time.

FIG. 8 is a block diagram of a conventional welding condition monitoring apparatus.

FIG. 9 is an output data diagram of a welding condition monitoring result according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Robot control device main body 2 Teach pendant (TP) 3 Welding power supply 4 Robot main body 7 Welding torch

[Procedure amendment]

[Submission date] March 13, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

According to a first aspect of the present invention, when a robot arm (welding torch) reaches a welding start point, a welding condition command and a welding start command are transmitted to a welding power source. A welding robot control device that issues a crater welding condition command and a welding end command to a welding power source when the robot arm (welding torch) reaches a welding end point. An input means having a welding power source for obtaining a voltage and an external interface circuit, capable of inputting an allowable range value for a teaching welding condition command, and a RAM for storing the allowable range value; Arc welding with a configuration in which the robot controller has a CPU for processing whether or not the current / voltage command values are within upper / lower limit values (permissible range). It is made to have the matter monitoring function. Next, the second means of the present invention uses the configuration of the first means, and when a condition range deviation state occurs during the monitoring of arc welding conditions, the welding condition upper and lower limit values are set at the end of crater welding, which is the end of one welding stroke. And the number of deviations and the operation information of the robot at the time of occurrence of the state (job No., program No., step N
o) is connected to information notifying means for displaying the information. Next, the third means of the present invention uses the configuration of the first means to chronologically organize the operation information of the robot at the time of deviating from the allowable range value in the arc welding condition monitoring function, and
The data is stored in the M and stored after the main power is turned off, so that the operator can obtain the operating information of the robot via the information notifying means whenever necessary. . Next, the fourth means of the present invention comprises the first
Using the configuration of the means, in order to exclude the section where the welding condition is unstable from the welding condition monitoring target section, a monitoring start delay time immediately after the start of welding can be set, and the robot control that delays the start of welding condition monitoring by the set time It has an apparatus main body. The external interface circuit is a communication control unit for exchanging control signals with the welding power source, and is controlled by a CPU unit on the welding power source side via a bus. In addition, this external interface circuit is configured to obtain the actual welding current value and actual welding voltage value to perform welding control, and these actual values are input to the robot controller main unit through communication or directly from the welding power supply. It is not necessary to add a special device for detecting the welding current / voltage.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, a robot control device main body 1 is connected to a teaching TP2 by a communication line control line L1, and is connected to a welding power source 3 by a communication control line L2. The operator moves the robot main body 4 minutely while directly watching the welding torch 7 arranged at the control reference point of the industrial robot while operating the TP2, and teaches the robot in order of the work to be performed. The teaching data is stored in the RAM 8 of FIG. The operator fixes the work 5 to be welded to the base material 6 and
Is operated to move the welding torch 7 to the welding start point a in FIG. 3, and the teaching position data and that the point is the welding start point;
In addition, a one-key registration of a welding condition command (welding current value / welding voltage value) and a welding start command (arc-on processing sequence) is performed using the welding registration key 2a on TP2. Next, the welding torch 7 is moved by the robot body 4 to the welding end point b in FIG. 3, and the teaching position data and that the point is the welding end point, and the crater welding condition command (welding current value / welding voltage) Value), welding end command (arc-off sequence) to TP
One key registration is made with the welding end key 2b on the second key. The taught program is stored in the RAM 8 of FIG. 2 by the CPU unit, and the automatic welding system of FIG. 1 is automatically operated by the registered program that has been taught. The content of the welding operation is as follows. The robot main body 4 moves the welding torch 7 to a predetermined welding start position a of the work 5 at a welding start point a in FIG.
When the robot reaches the point, the robot controller 1
After the main welding conditions (welding current value / welding voltage value) stored in advance have been transmitted via the communication control line L2 to the welding power source 3, the welding start command is executed and an arc answer is returned from the welding power source 3. Along the predetermined welding path of the workpiece 5,
Arc welding is performed at a welding speed stored in advance. Thereafter, when the welding torch 7 reaches the welding end point b in FIG. 3, the crater welding conditions (welding current value
(The welding voltage value) is transmitted, the robot is stopped, and a welding end command for performing the crater process is executed. Thereafter, a wire stick check is performed. If there is no fusion of the wire 10 to the workpiece 5, the next teaching point is performed. Move to.

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

FIG. 6

[Procedure amendment 4]

[Document name to be amended] Drawing

[Correction target item name] Fig. 8

[Correction method] Change

[Correction contents]

FIG. 8

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B23K 9/127 509 B23K 9/127 509A

Claims (5)

[Claims] When a robot arm (welding torch) reaches a welding start point, a welding condition command or a welding start command is issued to a welding power source, and when the robot arm (welding torch) reaches a welding end point, A controller for an arc welding robot that issues a crater welding condition command and a welding end command to a welding power source, and has an external interface circuit that obtains at least one of an actual welding current value and an actual welding voltage value. An input means for inputting an allowable range value for the teaching welding command that has been taught, and a RAM for storing the allowable range value, wherein the actual welding value taken from outside during the actual welding is the welding condition command value minus the allowable value lower limit. ≦ Actual welding value ≦ Welding condition command value + CPU unit that determines whether the value is within the upper limit of the allowable value is provided in the robot controller main body, and the actual welding value is an allowable range value. If the vehicle deviates from the position, a control device for the arc welding robot is connected to an information notification means such as a teach pendant or a personal computer (PC) for displaying the operation information of the robot to the outside to provide an arc welding condition monitoring function. . 2. The control device for an arc welding robot according to claim 1, wherein the arc welding conditions are monitored only in the main welding section, and the crater processing section is ignored. 3. When the actual welding value deviates from an allowable range value, the number of deviations from the welding condition upper and lower limit values at the end of crater welding at the end of one welding step, the job number of the robot in which the deviation occurred, and a program The control device for an arc welding robot according to claim 1, wherein operation information such as No. and Step No. is displayed on an information detecting means such as a teach pendant or a personal computer. 4. The operation information of the robot at the time of deviating from the allowable range value is arranged in time series, stored in a RAM, and the RA
It has a battery that backs up M data and retains the data even when the main power supply is turned off. Whenever the operator needs it, the operation information of the robot is transmitted via the information detecting means such as a teach pendant or a personal computer. 2. The control device for an arc welding robot according to claim 1, wherein the control device is configured to obtain the following. 5. A robot control device main body for setting a monitoring start delay time immediately after the start of welding to exclude a section in which the welding condition is unstable from a welding condition monitoring target section and delaying the start of welding condition monitoring by that time. The control device for an arc welding robot according to claim 1.