JP2012245558A - Arc welding robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the following problem: since abnormality monitoring during welding is carried out only by a robot control device side, the abnormality monitoring does not function when a control device itself is not normally operated.SOLUTION: An arc welding robot includes: a manipulator M; the robot control device RC outputting a welding command signal Ws on the basis of teaching; and a welding power source WP for performing welding treatment on the basis of the welding command signal Ws. The robot control device RC outputs process design information including treatment time related to the welding treatment. Further, the welding execution state is monitored on the basis of a welding state signal Wc and the process design information which are input from the welding power source WP. The welding power source WP outputs the welding state signal Wc which shows the present state of the welding treatment and the welding execution state is monitored on the basis of the process design information from the robot control device RC. By monitoring each state mutually, unexpected situation that the manipulator M stops while the welding is continued, can be prevented.

Description

  The present invention relates to an arc welding robot having an abnormality monitoring function during arc welding.

  FIG. 12 is a system configuration diagram of a conventional arc welding robot that performs consumable electrode arc welding. In the figure, the robot controller RC outputs an operation control signal Mc for controlling the operation of a plurality of servo motors arranged in the manipulator M based on teaching data Td created in advance by the teach pendant TP. At the same time, interface signals including a welding signal St, a feed speed setting signal Fr, a welding voltage setting signal Vr, and an arc confirmation signal Sa are transmitted to and received from the welding power source WP. The welding power source WP transmits and receives the interface signal, outputs a welding voltage Vw and a welding current Iw, and outputs a feed control signal Fc for controlling the wire feed motor WM. The manipulator M mounts the wire feed motor WM, the welding torch 4 and the like, and moves the tip position of the welding torch 4 along the teaching data Td taught in advance. The welding wire 1 is fed through the welding torch 4 by a wire feeding motor WM, and an arc 3 is generated between the base metal 2 and welding is performed.

  FIG. 13 is a timing chart when arc welding is performed by a conventional arc welding robot. (A) in the figure shows the welding signal St, (B) in the figure shows the gas output signal Gs, (C) shows the arc confirmation signal Sa, and (D) shows the feed speed setting signal Fr. Fig. (E) shows the welding voltage Vw, Fig. (F) shows the welding current Iw, and Fig. (G) shows the time change of the moving speed Sp of the manipulator M. Hereinafter, a description will be given with reference to FIG.

(1) Time t1 to t2 (preflow processing period)
At time t1, as shown in FIG. 5B, a gas output signal Gs is output from the robot controller RC, and so-called preflow processing is started. The preflow process may be started after the welding torch 4 reaches the welding start position and stops by the manipulator M, or may be started in advance before reaching the welding start position. When the pre-flow process is performed after the welding torch 4 reaches the welding start position, as indicated by the solid line in FIG. 5G, the welding torch 4 is stopped at time t1, so the moving speed Sp is “0. Is. When the preflow process is performed before reaching the welding start position, as indicated by a dotted line in FIG. 4G, the process is stopped at time t2 while decelerating during this period. Note that the preflow process is performed for a predetermined preflow time (period from time t1 to time t2).

(2) Time t2 to t3 (arc start processing period)
At time t2, as shown in FIG. 3A, the robot controller RC outputs a welding signal St at a high level (meaning start). At this time, as shown in FIG. 4D, the feed speed setting signal Fr becomes a slow-down feed speed, and the welding wire 1 is fed at a slow slow-down feed speed Fi. At the same time, as shown in FIG. 5E, the welding power source WP starts outputting, and the welding voltage Vw becomes a no-load voltage. When the welding wire 1 contacts the base material 2 at time t3, an arc is generated.

(3) Time t3 to t4 (steady welding period)
When an arc occurs at time t3, an arc confirmation signal Sa is output from the welding power source WP (changes to a high level) as shown in FIG. At the same time, as shown in FIG. 4D, the feed speed setting signal Fr becomes the steady feed speed Fs, and the steady feed of the welding wire 1 is started. Further, as shown in FIG. 5F, energization of the steady welding current Is corresponding to the steady feeding starts. Further, as shown in FIG. 5G, the welding torch 4 starts moving at the welding speed Ss along the weld line. This steady welding is performed during the period up to time t4.

(4) Time t4 to t5 (crater processing period)
When the manipulator M reaches the welding end position at time t4, the feed speed setting signal Fr becomes the crater feed speed Fe and the feed of the welding wire 1 becomes the crater feed speed as shown in FIG. Be changed. Further, as shown in FIG. 5G, the moving speed Sp becomes 0, and the welding torch 4 stops at the welding end position. And as shown to the figure (E) and (F), crater welding is performed by supplying the crater welding voltage Ve and the crater welding current Ie until time t5.

(5) Time t5 to t6 (welding end processing period)
At time t5, as shown in FIG. 5E, a welding release voltage Va higher than the steady welding voltage Vs is applied. This process is performed for a predetermined welding release time. By this welding release processing, the welded portion and the welding wire 1 are prevented from welding at the welding end position. In addition, during the period up to time t6, as shown in FIG. 5B, after-flow processing for continuing output of the shielding gas is performed. By this after-flow treatment, oxidation and weld cracking in the vicinity of the welding end position are prevented.

  As described above, in the conventional arc welding robot, arc welding is performed by the robot controller RC outputting the welding command signal based on the teaching data to the welding power source WP during the period of time t1 to t5. In such an arc welding robot, for example, when an arc is generated by the welding signal St from the robot controller RC, but the arc confirmation signal Sa is not returned to the robot controller RC due to disconnection or the like, the arc confirmation signal Sa However, the manipulator M cannot start moving and remains stopped. Therefore, the conventional arc welding robot has an abnormality monitoring function in order to prevent the abnormal situation as described above.

  For example, in Patent Document 1, when an unintended stop state of the manipulator M occurs due to a physical failure of the system such as a signal line disconnection, it leads to a dangerous situation or a major accident. There has been disclosed a robot control apparatus capable of preventing the above-mentioned problem. More specifically, the command pulse value to the motor is monitored, and the motor is stopped if the command pulse value is 0 for a predetermined time or more. Further, when monitoring the command pulse value, the section a shown in FIG. 13 (period in which welding start processing is performed in a state where the manipulator M is stopped) and the section b (welding is performed while actually moving the manipulator M). Monitoring period). In other words, since the unintended stop state of the manipulator M is monitored by periodically monitoring the command pulse value, the section b where the manipulator M is stopped is also monitored at the same short cycle as when moving. If it is performed, it is determined that the vehicle is in a stopped state although the original correct process is being performed. For this reason, the section b is monitored with a longer monitoring cycle than the section a. By configuring in this way, it is possible to prevent a dangerous situation or a major accident from occurring.

JP 2000-334690 A

However, the conventional technique described in Patent Document 1 described above has the following problems.
(1) Since the monitoring unit is provided only in the robot controller RC, if the monitoring unit does not operate normally due to incomplete software, the abnormality monitoring may not function.
(2) When monitoring the command pulse value, the monitoring cycle is set longer than the interval b in the interval a (see FIG. 13) until the actual welding is started. However, as a technique often used in actual arc welding processing, after starting welding at the welding start position, it is necessary to wait for a timer command to wait for the arc to stabilize or to ensure penetration. There may be a timed stop welding period. During this stop welding period, since it corresponds to the section b in the prior art, the manipulator M is regarded as stopped, and an abnormality is erroneously detected.
(3) As shown in the period from time t4 to time t5 in FIG. 13, crater welding may be performed at the welding end position. This period corresponds to the section b in the prior art, and because the stop of the manipulator M is monitored with a short monitoring cycle, an abnormality is erroneously detected.
(4) In order to avoid the erroneous detection of the above (2) and (3) in the prior art, it is necessary to set a longer monitoring cycle. However, if the monitoring cycle is set to be long, if arc welding is continued while the manipulator M is stopped unintentionally, the time until the welding is stopped becomes long, and the original purpose of the monitoring function may not be achieved. is there.
(5) As shown at times t5 to t6 in FIG. 13, the welding release process is usually executed at the end of welding. These processes are not a welding command signal from the robot controller RC, but are performed independently by the welding power source WP. And since the execution time required for these processes changes depending on the welding state, if abnormality monitoring is performed, it is necessary to set an appropriate monitoring cycle according to the state. Not.

  Accordingly, an object of the present invention is to provide a highly reliable arc welding robot in which an abnormality monitoring function during arc welding processing is remarkably improved.

In order to achieve the above object, the invention of claim 1
A manipulator holding a welding torch, a robot controller for driving and controlling the manipulator based on pre-created teaching data, and sequentially outputting a welding command signal for performing arc welding processing; and based on the welding command signal In an arc welding robot equipped with a welding power source device that performs welding control and supply of welding power,
The robot control device is a welding command generating means for outputting process plan information including a processing time related to the arc welding process, and a signal input from the welding power source device and indicating a current state of the arc welding process First monitoring means for monitoring an execution state of the arc welding process based on a welding state signal and the process plan information,
The welding power source device performs a welding control and outputs a welding state signal according to the current state, and a second monitoring for monitoring an execution state of the arc welding process based on the process plan information. And an arc welding robot.

The invention of claim 2
In the arc welding process with the welding torch stopped,
When the process plan information including the processing time is output by the welding command generation unit, the first monitoring unit starts measuring a first elapsed time that is an elapsed time from the output time point, and It is monitored whether or not the welding state signal corresponding to the welding command signal is input from the welding power source device until the elapsed time reaches the processing time. Output a stop signal,
When the arc control process is started by the welding control unit, the second monitoring unit starts measuring a second elapsed time that is an elapsed time from the start time, and the second elapsed time is the processing time. 2. The arc welding robot according to claim 1, wherein whether or not the next welding command signal is input until the time of reaching is reached is monitored, and if not input, the arc welding process being executed is stopped. It is.

The invention of claim 3
The welding command generation means outputs, as the process plan information, a next process command indicating a welding command signal scheduled to be output in the next process, in addition to the processing time.
The arc welding robot according to claim 2, wherein the next welding command signal is a welding command signal indicated by the next process command.

The invention of claim 4
The welding control means gives an execution completion time, which is a time required for the arc welding process during the process, to the welding state signal and outputs it,
When the welding state signal including the execution completion time is input from the welding control unit, the first monitoring unit starts measuring a third elapsed time that is an elapsed time from the input time point, and It is monitored whether or not the next welding state signal is input from the welding power source until the elapsed time reaches the execution completion time. If not, an emergency stop signal is output to the welding power source. The arc welding robot according to claim 2 or 3, wherein the arc welding robot is provided.

The invention of claim 5
The robot controller is configured to calculate a position of the welding torch for each predetermined period based on the teaching data, and an arrival signal that outputs a position arrival signal when the welding torch reaches the calculated position. And an output means,
During steady welding while moving the welding torch, the welding control means outputs a welding signal as the welding state signal at a predetermined cycle,
The first monitoring means monitors whether or not the welding signal is input at every predetermined period, and if not input, outputs an emergency stop signal to the welding power source device,
The said 2nd monitoring means monitors whether the said position arrival signal is input within the predetermined arrival signal waiting time, and when not input, stops the said regular welding. Arc welding robot.

The invention of claim 6
At the time of the preflow process in which the shield gas output is started in advance by a predetermined preflow time,
The welding command generating means outputs a preflow start signal including the preflow time as the processing time,
When the output of the shield gas is started by the welding control means, the second monitoring means starts measuring the second elapsed time that is an elapsed time from the start time, and the second elapsed time is 2. The output of the shield gas is stopped if it is monitored whether or not an arc start signal is input from the robot controller until the preflow time is reached. Arc welding robot.

The invention of claim 7
At the time of the preflow process in which the shield gas output is started in advance by a predetermined preflow time,
The welding command generating means outputs a preflow start signal including the preflow time as the processing time and an arc start command as the next process command,
When the preflow start signal is output, the first monitoring unit starts measuring the first elapsed time that is an elapsed time from the output time until the first elapsed time reaches the preflow time. During this period, it is monitored whether or not a preflow start completion signal as the welding state signal is input from the welding power supply device. And
When the output of the shield gas is started based on the preflow start signal, the second monitoring means starts measuring the second elapsed time that is an elapsed time from the start time, and the second elapsed time Whether or not the arc start signal indicated by the next process command is input until the preflow time is reached, and if not input, the output of the shielding gas is stopped. The arc welding robot according to claim 3.

The invention of claim 8
During arc start processing that generates arcs,
The welding command generating means outputs an arc start signal including an arc start failure detection time as the processing time,
When the arc start signal is output, the first monitoring means starts measuring the first elapsed time that is an elapsed time from the output time, and the first elapsed time is set to the arc start failure detection time. Monitoring whether or not the welding state signal is input from the welding power supply device every predetermined period until it reaches, if not, output an emergency stop signal to the welding power supply device,
When the ignition process is started based on the arc start signal, the second monitoring unit starts measuring the second elapsed time that is an elapsed time from the start time of the ignition process, and Monitor whether or not an arc is generated instead of the next welding command signal until the elapsed time reaches the arc start failure detection time, and stop the ignition process if no arc occurs. The arc welding robot according to claim 2.

The invention of claim 9
During crater processing to form the weld end,
The welding command generation means outputs a crater welding signal including a crater welding time as the processing time,
When the output of the welding power is changed based on the crater welding signal, the second monitoring means measures the first elapsed time, which is an elapsed time from the change of the welding power output, and the first elapsed time. 2. The arc welding robot according to claim 1, wherein if the arc end signal is not input from the robot control device even if the time exceeds the crater welding time, the crater welding is stopped.

The invention of claim 10
During crater processing to form the weld end,
The welding command generation means outputs a crater welding signal including a crater welding time as the processing time and an arc end command as the next process command,
When the crater welding signal is output, the first monitoring means starts measuring the first elapsed time that is an elapsed time from the output time point, and the first elapsed time reaches the crater welding time. Until whether or not a crater welding completion signal as the welding state signal is input from the welding power supply device, and if not input, an emergency stop signal is output to the welding power supply device,
When the output of the welding power is changed based on the crater welding signal, the second monitoring means measures the second elapsed time, which is an elapsed time from the change in output of the welding power, and the second elapsed time. Whether or not the arc end signal indicated by the next process command is input before the time reaches the crater welding time is monitored, and if not input, the crater welding is stopped. An arc welding robot according to claim 3.

The invention of claim 11
During arc end processing to stop the arc,
The welding command generating means outputs an arc end signal including an arc end waiting time as the processing time,
The welding control means outputs an arc extinguishing signal and the execution completion time as the welding state signal when the arc extinguishing process is started based on the arc end signal, and then proceeds to the welding release process when the process proceeds to the welding release process. A welding release signal as a welding state signal and the execution completion time are output, and when all arc end processing is completed, an arc end completion signal is output as the welding state signal,
The first monitoring means measures the first elapsed time which is an elapsed time from the output time of the arc end signal,
When the arc extinguishing signal or the welding release is not input, it is monitored whether the arc end completion signal is input before the first elapsed time reaches the arc end waiting time, If not input, an emergency stop signal is output to the welding power source,
When the arc extinguishing signal or the welding release signal is input, the measurement of the first elapsed time is stopped and the elapsed time from the input time of the arc extinguishing signal or the welding release signal is When re-measurement is started as one elapsed time, and it is monitored whether or not the next welding state signal is input before the re-measured first elapsed time reaches the execution completion time. Outputs an emergency stop signal to the welding power source,
When the arc extinguishing process is started based on the arc end signal, the second monitoring unit starts measuring the second elapsed time, which is an elapsed time from the process start time, and the second elapsed time. Monitor whether or not a shield gas stop signal is input from the robot controller until the arc end waiting time is reached, and if not, output an abnormal signal to the robot controller The arc welding robot according to claim 4.

  According to the present invention, the robot control device and the welding power supply device mutually monitor the respective states, thereby preventing an unexpected situation such as the manipulator stopping while continuing the arc welding process. Can do.

System configuration diagram of arc welding robot according to the present invention Functional block diagram of robot controller and welding power source Timing chart showing an example of a welding sequence of the arc welding robot according to the present invention Flow chart for monitoring mutual anomalies during preflow processing Flow chart showing the flow of processing of the robot controller when performing mutual abnormality monitoring during arc start processing Flow chart showing the processing flow of the welding power source when performing mutual abnormality monitoring during arc start processing Flowchart for mutual abnormality monitoring during stop welding Flowchart for performing mutual abnormality monitoring during steady welding while moving TCP Flowchart for mutual abnormality monitoring during crater welding processing The flowchart which shows the flow of a process of the robot controller RC when performing a mutual abnormality monitoring during an arc end process Flow chart when abnormality monitoring is performed only with the welding power source WP System configuration diagram of a conventional arc welding robot that performs consumable electrode arc welding Timing chart for arc welding with a conventional arc welding robot

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on examples with reference to the drawings.

[Embodiment 1]
FIG. 1 is a system configuration diagram of an arc welding robot according to the present invention. In the figure, the robot controller RC outputs an operation control signal Mc for controlling the operation of a plurality of servo motors arranged in the manipulator M based on teaching data Td created in advance by the teach pendant TP. Further, a welding command signal Ws (welding signal St, gas output signal Gs, feed speed setting signal Fr, welding voltage setting signal Vr, etc.) and a position arrival signal Rs described later are output to the welding power source WP. The welding power source WP receives the above-mentioned various signals, supplies a welding voltage Vw and a welding current Iw, outputs a shielding gas by controlling a gas cylinder (not shown), and outputs a feeding control signal Fc to send a wire. The feed motor WM is driven to rotate. Further, an arc confirmation signal Sa as a response signal and a welding state signal Wc indicating the current state of the arc welding process are output to the robot controller RC. The manipulator M mounts the wire feed motor WM, the welding torch 4 and the like, and moves the tip position of the welding torch 4 (hereinafter simply referred to as TCP) along the teaching data Td taught in advance. The welding wire 1 is fed through the welding torch 4 by a wire feeding motor WM, and an arc 3 is generated between the base metal 2 and welding is performed.

  FIG. 2 is a functional block diagram of the robot controller RC and the welding power source WP. First, the robot controller RC will be described. The robot control device RC includes a CPU 12, a RAM 13, a communication interface unit 14, a timer 17, a ROM 11, a drive command unit 15 and a hard disk 16, and each unit is connected via a bus 18.

  The CPU 12 is a central processing unit and executes a software program stored in the ROM 11 on an operating system (not shown). The RAM 13 is a temporary calculation area. The communication interface unit 14 performs digital communication with the welding power source WP. The timer 17 measures time. The ROM 11 stores software programs executed by the CPU 12 and control constants. The hard disk 16 stores teaching data Td and user setting constants such as a preflow time described later. The drive command unit 15 outputs a servo control signal for rotationally driving each servo motor of the manipulator M. The CPU 12 corresponds to welding command generation means, first monitoring means, position calculation means, and arrival signal output means.

  The ROM 11 described above includes an interpretation execution unit 21 as a software program, an operation control unit 22, a welding command generation unit 23, a welding monitoring unit 24, and a position monitoring unit 25.

  The interpretation execution unit 21 interprets the teaching data Td and notifies the operation control unit 22 and the welding command generation unit 23 of the interpretation result. Based on the interpretation result, the operation control unit 22 performs a trajectory plan calculation for calculating TCP for each predetermined period, and notifies the drive command unit 15 of the calculation result. The welding command generation unit 23 transmits various welding command signals Ws for performing the arc welding process to the welding power source WP via the communication interface unit 14 based on the interpretation result of the teaching data Td. To the welding command signal Ws, processing time related to the arc welding processing and identification information of the welding command signal Ws scheduled to be notified next are added as process plan information. The welding monitoring unit 24 monitors the execution state of the arc welding process based on the welding state signal Wc indicating the current state of the arc welding process and the process plan information. The position monitoring unit 25 outputs a position arrival signal Rs when the welding torch 4 arrives at the track planned position calculated by the operation control unit 22 during steady welding while moving the welding torch 4.

  Next, the welding power source WP will be described. The welding power source WP includes a CPU 32, a RAM 33, a communication interface unit 34, a ROM 31, a current / voltage detection unit 35, and a hard disk 36. The CPU 32 is a central processing unit and executes a software program stored in the ROM 31 on an operating system (not shown). The RAM 33 is a temporary calculation area. The communication interface unit 34 performs digital communication with the robot control device RC. . The ROM 31 stores software programs executed by the CPU 32 and control constants. The hard disk 36 stores, for example, a central adjustment table for adjusting the welding voltage value, a processing time calculation table for calculating a welding release time, monitor data, and the like. The current / voltage detector 35 digitally converts a welding current value and a welding voltage value detected by a current / voltage detection line (not shown). The CPU 32 corresponds to a welding control unit and a second monitoring unit.

  The ROM 31 described above includes a welding control unit 43 and a welding monitoring unit 44 as software programs. The welding control unit 43 performs control for arc welding processing and power supply based on the welding command signal Ws. Further, a welding state signal Wc for indicating the current state of the arc welding process is generated and output to the robot controller RC via the communication interface unit 34. The welding monitoring unit 44 monitors the execution state of the arc welding process based on the process plan information from the robot controller RC.

  Although not shown, the robot controller RC and the welding power source WP are connected by a so-called emergency stop line so that an emergency stop is possible.

  Hereinafter, an operation of the arc welding robot configured as described above will be described. First, a general welding process from the start to the end of welding will be described step by step. Then, the effect | action of this invention applied to each welding process is demonstrated concretely.

  FIG. 3 is a timing chart showing an example of a welding sequence of the arc welding robot according to the present invention. (A) in the figure shows the welding signal St, (B) in the figure shows the gas output signal Gs, (C) shows the arc confirmation signal Sa, and (D) shows the feed speed setting signal Fr. Fig. (E) shows the welding voltage Vw, Fig. (F) shows the welding current Iw, and Fig. (G) shows the time change of the moving speed Sp of the manipulator M. Hereinafter, with reference to the same figure, it demonstrates centering on a different part from FIG. 13 demonstrated as a prior art.

(1) Time t1 to t2 (preflow processing period)
When the TCP reaches the welding start position at time t1, a gas output signal Gs is output from the robot controller RC as shown in FIG. The gas output signal Gs includes a preflow time as process plan information. It is even better if the process plan information includes information (next process command) indicating a welding command signal scheduled to be output in the next welding process. The next process command in this processing stage is a welding signal St to be output after completion of the preflow process. Note that, as described with reference to FIG. 13, the preflow process may be started after the TCP stops at the welding start position, or may be started before the arrival. In this embodiment, the case where the preflow process is performed after the TCP reaches the welding start position is selected. For this reason, as shown in FIG. 5G, TCP is stopped after time t1.

(2) Time t2 to t3 (arc start processing period)
At time t2, a welding signal St is output at a high level from the robot controller RC as shown in FIG. The welding signal St includes an arc start failure detection time as process plan information. At this time, as shown in FIG. 4D, the welding wire 1 is fed at a slow slow-down feeding speed Fi, and an arc is generated when the welding wire 1 contacts the base material 2 at time t3. If no arc occurs within the arc start failure detection time, the process is stopped.

(3) Time t3 to t4 (stop welding period with TCP stopped)
In this period, a timer command for stopping the TCP at the welding start position is taught as a stop welding period in which the TCP is stopped for a while in order to stabilize the arc immediately after the start of welding. When an arc occurs at time t3, an arc confirmation signal Sa is output from the welding power source WP (changes to a high level) as shown in FIG. At the same time, as shown in FIG. 4D, the welding wire 1 starts to be fed at the steady feeding speed Fs. And stop welding is performed for the period to time t4. Although not shown, the stop time given to the timer command is output from the robot controller RC to the welding power source WP at the time t3. The output timing of the stop time may be the timing at time t2 by prior interpretation.

(4) Time t4 to t5 (steady welding period while moving the TCP)
When the timer command is canceled at time t4, the TCP starts to move at the welding speed Ss by the operation control signal Mc from the robot controller RC as shown in FIG. This steady welding is performed during the period up to time t5.

(5) Time t5 to t6 (crater processing period)
When TCP reaches the welding end position at time t5, the robot controller RC outputs a crater welding signal. The crater welding signal includes crater welding time as process plan information. Information indicating an arc end signal as the next process command may be included in the process plan information. At this time, the TCP stops at the welding end position as shown in FIG. Further, as shown in FIG. 4D, the feeding speed of the welding wire 1 is the crater feeding speed Fe. Then, as shown in FIGS. 5E and 5F, crater welding is performed by applying a crater welding voltage Ve and a crater welding current Ie.

(6) Time t6 to t7 (welding end processing period)
At time t6, the robot controller RC outputs an arc end signal (outputs the welding signal St at a low level). At this time, the feeding of the welding wire 1 is stopped as shown in FIG. In addition, as shown in FIGS. 5E and 5F, energization is continued for a predetermined time with respect to the crater welding voltage Ve and the crater welding current Ie. This process is called an arc extinguishing process (burnback), and the welding power source WP automatically performs the process. After the arc extinguishing process is completed, a welding release process for applying a welding release voltage Va higher than the steady welding voltage Vs is performed as shown in FIG. These series of welding end processes are performed until time t7.

(7) Time t7 to t8 (afterflow processing period)
At time t7, the robot controller RC outputs the afterflow time. As a result, as shown in FIG. 5B, afterflow processing is performed in which the output of the shield gas is continued for a period up to time t8.

  In addition, the section a shown to the figure has shown the period which performs an arc welding process in the state which stopped TCP. In the present invention, when the arc welding process is performed with the TCP stopped, monitoring is performed as follows.

(A) Processing on Robot Control Device RC Side First, prior to each welding process, the welding command generator 23 outputs a welding command signal Ws. At this time, the welding process time and the next process command as process plan information are also output. The welding processing time is the above-described preflow time or arc start failure detection time. The next process command is information indicating a welding command signal scheduled to be output in the next welding process. Next, the welding monitoring unit 24 starts measuring a first elapsed time that is an elapsed time from the output time point of the welding command signal Ws. Then, whether or not the welding state signal Wc corresponding to the welding command signal Ws is input from the welding power source WP until the first elapsed time reaches the welding processing time is monitored. An emergency stop signal is output to WP.

(B) Processing on the side of the welding power source WP On the other hand, on the side of the welding power source WP, the welding control unit 43 starts arc welding processing based on the welding command signal Ws from the robot controller RC. The welding monitoring unit 44 starts measuring the second elapsed time, which is the elapsed time from the start of the arc welding process, and the next welding command signal until the second elapsed time reaches the welding process time. Is not input, and if not input, the current arc welding process is stopped. Here, the next welding command signal may be a predetermined welding command signal Ws or a welding command signal Ws indicated by a next process command notified from the robot controller RC.

  Hereinafter, the operation in the case where the mutual abnormality monitoring is performed by the robot controller RC and the welding power source WP will be specifically described by taking as an example the case of performing the preflow process (period of time t1 to t2 in FIG. 3). In the following, for ease of explanation, the processing of each part of the robot controller RC and the welding power source WP is described in one flow.

  FIG. 4 is a flowchart for performing mutual abnormality monitoring during the preflow process. FIG. 4A shows processing on the robot controller RC side, and FIG. 4B shows processing on the welding power source WP side.

(A) Processing on the Robot Controller RC Side In step S11, the welding command generator 23 outputs a gas output signal Gs.
In step S12, the welding monitoring unit 24 sets the preflow time given to the gas output signal Gs as the monitoring time. At the same time, measurement of the elapsed time (first elapsed time) from the output time point of the gas output signal Gs is started.

  In step S13, the welding monitoring unit 24 determines whether a gas output start completion signal is input from the welding power source WP. If not, the process proceeds to step 14. If entered, the process proceeds to normal processing. For example, in the case of the preflow process, the normal process refers to a process of waiting until the preflow time elapses and outputting the next welding command signal Ws (welding start command) when the preflow time elapses. That is, it should be understood that the process is performed when no abnormality is detected and the same process as that of the prior art is performed (the same applies to the following description).

  In step S <b> 14, the welding monitoring unit 24 determines whether or not the first elapsed time that started measurement in step S <b> 12 has exceeded the monitoring time (preflow time). If not, return to Step 13. If exceeded, the process proceeds to step S15. In step S15, an emergency stop signal is output to the welding power source WP to urgently stop the welding process.

(B) Processing on the side of the welding power source WP In step S21, the welding control unit 43 determines whether or not the signal notified from the robot control device RC is the gas output signal Gs. If it is the gas output signal Gs, the process proceeds to step S22. In step S <b> 22, the welding control unit 43 controls to open the gas solenoid valve of the gas cylinder and starts a preflow process for ejecting the shield gas. In step S23, the welding control unit 43 outputs a gas output start completion signal as the welding state signal Wc.

  In step S24, the welding monitoring unit 44 sets the preflow time given to the gas output signal Gs notified from the robot controller RC as the monitoring time. At the same time, measurement of the elapsed time (second elapsed time) from the start time of the preflow process is started.

  In step S25, the welding monitoring unit 44 determines whether or not the welding signal St that is the next welding command signal has been received. Here, when the next process command is given to the welding command signal Ws notified at the start of the preflow process, it may be determined whether or not the given next process command is input. If entered, the process proceeds to normal processing. If not input, the process proceeds to step S26.

  In step S26, the welding monitoring unit 44 determines whether or not the second elapsed time that started the measurement in step S24 has exceeded the monitoring time (preflow time). If not, the process returns to step 25. If exceeded, the process proceeds to step S27. In step S27, the welding control unit 43 closes the gas solenoid valve of the gas cylinder to stop the ejection of the shield gas.

  As described above, in the first embodiment, the mutual abnormality monitoring is performed by the robot controller RC and the welding power source WP during the preflow process.

In the above, the mutual abnormality monitoring method in a state where TCP is stopped has been described as an example of performing the preflow process. However, if the arc welding process is performed in a state where TCP is stopped, at least in FIG. Mutual abnormality monitoring can be performed in exactly the same manner during the following period.
・ Time period t2 to t3 (arc start processing period)
-Time period from t3 to t4 (stop welding process period)
・ Time period from t5 to t6 (crater processing period)
-Time period from t7 to t8 (afterflow processing period)

[Embodiment 2]
Next, a second embodiment of the present invention will be described. In the second embodiment, mutual abnormality monitoring is performed by the robot controller RC and the welding power source WP during the arc start process (period t2 to t3 in FIG. 3). The difference from the first embodiment is that the welding power supply signal WP is notified of the welding state signal Wc after being subdivided according to the state transition during the arc start process (arc not generated, wire slowing down, arc generated, etc.). In addition, while determining whether or not the subdivided welding state signal Wc is notified every predetermined cycle, if not notified, the welding power source WP is emergency stopped.

  FIG. 5 is a flowchart showing a process flow of the robot controller RC when performing mutual abnormality monitoring during the arc start process.

  In step S11, the welding command generator 23 outputs a welding start command (the welding signal St is set to the high level). In step S12, the welding monitoring unit 24 sets the arc start failure detection time given to the welding signal St as the monitoring time. At the same time, measurement of the elapsed time (first elapsed time) from the output time of the welding signal St is started.

  In step S13, the welding monitoring unit 24 sets a reception interval time. At the same time, measurement of the elapsed reception time from the latest reception time is started. The reception interval time is set to an arbitrary time interval such as 0.1 seconds, which is longer than the communication cycle between the robot controller RC and the welding power source WP, but does not cause damage when an abnormal situation occurs. It is good to set in.

  In step S14, the welding monitoring unit 24 determines whether or not an arc generation signal as a welding state signal Wc is input from the welding power source WP. If not, the process proceeds to step 15. If entered, the process proceeds to normal processing.

  In step S15, the welding monitoring unit 24 determines whether or not the first elapsed time that started the measurement in step S12 has exceeded the monitoring time (arc start failure detection time). If not, the process proceeds to step S16. When exceeding, it transfers to step S19, and while outputting a stop signal to welding power supply WP, the abnormal signal to the effect that the arc start failed is output outside.

  In step S16, it is determined whether or not an arc non-occurrence signal, a wire slowing down signal, or the like as a welding state signal Wc is notified from the welding power source WP. If notified, the process returns to step S13. When not notified, it transfers to step S17. In step S17, it is determined whether or not the reception elapsed time whose measurement is started in step S13 exceeds the set reception interval time. If not, the process returns to step S14. If exceeded, the process proceeds to step S18. In step S18, an emergency stop signal is output to the welding power source WP to urgently stop the welding process.

  FIG. 6 is a flowchart showing a processing flow of the welding power source WP when mutual abnormality monitoring is performed during the arc start processing.

  In step S21, the welding control unit 43 drives the inverter of the welding power source WP based on the welding signal St notified from the robot controller RC and starts slowing down the welding wire 1 to approach the base material 2. The so-called ignition process is started. In step S22, the welding monitoring unit 44 sets the arc start failure detection time given to the welding signal St notified from the robot controller RC as the monitoring time. At the same time, measurement of the elapsed time (second elapsed time) from the start time of the ignition process is started.

  In step S23, the welding control unit 43 outputs a welding state signal Wc corresponding to the current state to the robot controller RC. The welding state signal Wc here refers to a signal for informing various state transitions such as arc not generated, during wire slowdown, and arc generation.

  In step S24, the welding monitoring unit 44 sets a transmission interval time. At the same time, measurement of the elapsed transmission time from the latest transmission time is started. Note that the transmission interval time is set to an arbitrary time interval such as 0.1 seconds, which is longer than the communication cycle between the robot controller RC and the welding power source WP, but does not cause damage when an abnormal situation occurs. It is good to set in.

  In step S25, the welding monitoring unit 44 determines whether or not an arc has occurred. If an arc has occurred, the process proceeds to step S26, and the fact is notified to the robot controller RC. Thereafter, normal processing is performed. If no arc has occurred, the process proceeds to step S27. In step S27, it is determined whether or not there is a stop signal input from the robot controller RC. If there is a stop signal input, the process proceeds to step S31. If there is no stop signal input, the process proceeds to step S28.

  In step S <b> 28, the welding monitoring unit 44 determines whether or not the second elapsed time that started the measurement in step S <b> 22 exceeds the monitoring time (arc start failure detection time). If not, the process proceeds to step 29. If exceeded, the process proceeds to step S30 to notify the robot controller RC of the arc start failure. Thereafter, in step S31, all the welding processes being executed are stopped. In step S29, it is determined whether or not the transmission elapsed time whose measurement is started in step S24 has exceeded the set transmission interval time. If not, the process returns to step S23 to continue the monitoring process.

  As described above, in the second embodiment, the mutual abnormality monitoring is performed by the robot controller RC and the welding power source WP during the arc start process.

[Embodiment 3]
Next, a third embodiment of the present invention will be described. In the third embodiment, mutual abnormality monitoring is performed by the robot controller RC and the welding power source WP during the stop welding period (period from time t3 to t4 in FIG. 3). The difference from the first embodiment is that in the stop welding period, the stop time is notified from the robot controller RC to the welding power source WP prior to stop welding, and the stop time is measured by the welding power source WP, and the stop time has passed. If the next welding command signal is not received, the welding process is stopped.

  FIG. 7 is a flowchart in the case of performing mutual abnormality monitoring during stop welding. FIG. 4A shows processing on the robot controller RC side, and FIG. 4B shows processing on the welding power source WP side.

(A) Processing on the Robot Control Device RC Side When the timer command is interpreted by the interpretation execution unit 21, the welding command generation unit 23 outputs the stop time determined by the timer command to the welding power source WP in step S11. To do. At this time, in addition to the stop time, a next process command indicating the next welding command signal Ws may be output simultaneously.

(B) Processing on the side of the welding power source WP In step S21, the welding control unit 43 determines whether or not the signal notified from the robot control device RC is the stop time given to the timer command. If it is the stop time, the process proceeds to step S22.

  In step S22, the welding monitoring unit 44 sets the stop time notified from the robot controller RC as the monitoring time. At the same time, measurement of the elapsed time from the reception time of the stop time is started.

  In step S23, the welding monitoring unit 44 determines whether or not the next welding command signal has been received. Here, when the next process command is given to the notified stop time, it is good to determine whether or not the given next process command is inputted. If entered, the process proceeds to normal processing. If not input, the process proceeds to step S24.

  In step S24, the welding monitoring unit 44 determines whether or not the elapsed time when the measurement is started in step S22 exceeds the monitoring time (stop time). If not, the process returns to step 23. If exceeded, the process proceeds to step S25, where it is assumed that some abnormality has occurred in the robot controller RC, and all the welding processes being executed are stopped.

  As described above, in the third embodiment, mutual abnormality monitoring is performed by the robot controller RC and the welding power source WP during stop welding. In the above, the case of stop welding using a timer command is shown as an example, but the present invention is not limited to this. For example, a weaving command for taking a leg length is taught, and a stop time is set at each end of the weaving. Even when is set, abnormality monitoring can be performed by the above-described processing.

[Embodiment 4]
Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, mutual abnormality monitoring is performed by the robot controller RC and the welding power source WP during the movement of the TCP (period from time t4 to t5 in FIG. 3).

  A section b in FIG. 3 shows a period in which steady welding is performed while moving the TCP. During this period, the welding control unit 43 of the welding power source WP outputs a welding signal as a welding state signal Wc at a predetermined cycle. Further, the operation control unit 22 of the robot controller RC calculates TCP for each predetermined period based on the teaching data Td. In addition, the position monitoring unit 25 constantly monitors the position of the TCP, and when the TCP reaches the position calculated by the operation control unit 22, the position monitoring unit 25 outputs a position arrival signal for notifying the arrival to the welding power source WP. . Monitoring is performed as follows.

  FIG. 8 is a flowchart in the case of performing mutual abnormality monitoring during steady welding while moving the TCP. FIG. 4A shows the processing of the welding monitoring unit 24 on the robot controller RC side, and FIG. 4B shows the processing of the welding monitoring unit 44 on the welding power source WP side. Both processes show a process after the occurrence of an arc and the start of movement (process after time t4 in FIG. 3).

(1) Processing on the Robot Control Device RC Side In step S11, a first monitoring time (for example, 0.1 msec) that is a cycle for monitoring a welding signal as a welding state signal Wc notified from the welding power source WP is used. Set. In step S12, measurement of elapsed time since the previous reception is started.

  In step S13, it is determined whether or not a welding signal is input from the welding power source WP. If it is input, it is assumed that welding is normally performed, and the process returns to step S12. If not, the process proceeds to step S14. In step S14, it is determined whether or not the first elapsed time that started the measurement in step S12 has exceeded the first monitoring time. If not, the process returns to step S13. When exceeding, it transfers to step S15, outputs an emergency stop signal to welding power supply WP, and stops a welding process urgently.

(2) Processing on the side of the welding power source WP In step S21, a second monitoring time (for example, 0.1 msec) that is a cycle for monitoring the position arrival signal Rs notified from the robot controller RC is set. In step S22, measurement of the elapsed time since the previous reception is started. In step S23, it is determined whether or not the position arrival signal Rs is input from the robot controller RC. If it is input, it is assumed that the TCP is moving normally, and the process returns to step S22. If not, the process proceeds to step 24.

  In step S24, it is determined whether or not the second elapsed time when the measurement is started in step S22 exceeds the second monitoring time. If not, the process returns to step S23. When exceeding, it transfers to step S25 and stops all the welding processes in execution.

  As described above, mutual abnormality monitoring is performed by the robot controller RC and the welding power source WP during steady welding while moving the TCP.

[Embodiment 5]
Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, mutual abnormality monitoring is performed by the robot controller RC and the welding power source WP during the crater welding period (period from time t5 to t6 in FIG. 3).

  FIG. 9 is a flowchart in the case of performing mutual abnormality monitoring during the crater welding process. FIG. 4A shows processing on the robot controller RC side, and FIG. 4B shows processing on the welding power source WP side.

(A) Processing on the Robot Controller RC Side In step S11, the welding command generator 23 outputs a crater welding signal.
In step S12, the welding monitoring unit 24 sets the crater welding time given to the crater welding signal as the monitoring time. At the same time, measurement of the elapsed time (first elapsed time) from the output point of the crater welding signal is started.

  In step S13, the welding monitoring unit 24 determines whether a crater welding signal is input from the welding power source WP. If not, the process proceeds to step 14. If entered, the process proceeds to normal processing.

  In step S14, the welding monitoring unit 24 determines whether or not the first elapsed time that started the measurement in step S12 exceeds the monitoring time (crater welding time). If not, return to Step 13. If exceeded, the process proceeds to step S15. In step S15, an emergency stop signal is output to the welding power source WP to urgently stop the welding process.

(B) Processing on the side of the welding power source WP In step S21, the welding control unit 43 determines whether or not the signal notified from the robot control device RC is a crater welding signal. If it is a crater welding signal, the process proceeds to step S22. In step S22, the welding control unit 43 adjusts the welding current value and the welding voltage value so that the set crater welding condition value is obtained. In step S23, the welding control unit 43 outputs a signal during crater welding as the welding state signal Wc.

  In step S24, the welding monitoring unit 44 sets the crater welding time notified from the robot controller RC as the monitoring time. At the same time, measurement of the elapsed time (second elapsed time) from the start of the crater welding process is started.

  In step S25, the welding monitoring unit 44 determines whether an arc end signal, which is the next welding command signal, has been received. Here, when the next process command is given to the welding command signal Ws notified at the start of the crater welding process, it may be determined whether or not the given next process command is input. If entered, the process proceeds to normal processing. If not input, the process proceeds to step S26.

  In step S26, the welding monitoring unit 44 determines whether or not the second elapsed time that started the measurement in step S24 exceeds the monitoring time (crater welding time). If not, the process returns to step 25. If exceeded, the process proceeds to step S27. In step S27, the welding control unit 43 stops all the welding processes being executed.

  As described above, in the fifth embodiment, the mutual abnormality monitoring is performed by the robot controller RC and the welding power source WP during the crater welding process.

[Embodiment 6]
Next, a sixth embodiment of the present invention will be described. In the sixth embodiment, mutual abnormality monitoring is performed by the robot controller RC and the welding power source WP during the arc end processing period (period from time t6 to t7 in FIG. 3). The mutual abnormality monitoring during the arc end process may apply the same process as in the first embodiment, but in addition to this process, when the welding power source WP outputs the welding state signal Wc, the arc being processed is processed. The execution completion time, which is the time required for the end processing (arc extinguishing processing and welding release processing), is output. Then, when the welding state signal Wc including the execution completion time is input, the robot controller RC starts measuring the elapsed time that is an elapsed time from the input time, and the elapsed time reaches the execution completion time. In the meantime, it is monitored whether or not the next welding state signal Wc is input from the welding power source WP. If not input, an emergency stop signal is output to the welding power source WP. The execution completion time described above is a time automatically calculated as a variable (state dependent variable) according to the welding state in the welding control unit 43 of the welding power source WP.

  FIG. 10 is a flowchart showing a process flow of the robot controller RC when performing mutual abnormality monitoring during the arc end process. Hereinafter, processing on the robot controller RC side will be described. In the processing of the welding power source WP, the processing shown in the first embodiment is replaced with the arc end processing, and the welding state signal Wc (the extinguishing signal, the welding release signal, the welding completion signal) is output according to the state. Since only the execution completion time, which is the time required for the arc welding process during the process, is output, the description is omitted.

  In step S11, the welding command generator 23 outputs an arc end signal (the welding signal St is set to a low level). As a result, the welding power source WP starts the arc extinguishing process, and outputs the arc extinguishing signal and the arc extinguishing completion time as the welding state signal Wc. After the arc extinguishing process, the presence / absence of welding is confirmed, and if it is determined that welding has occurred, the welding release process is started, and the welding release signal and the welding release completion time are output as the welding state signal Wc. The When it is determined that there is no welding, a welding completion signal is output as the welding state signal Wc.

  In step S12, the welding monitoring unit 24 sets the arc end waiting time given to the arc end signal as the monitoring time. At the same time, measurement of the elapsed time from the output point of the arc end signal is started.

  In step S13, the welding monitoring unit 24 determines whether or not the arc extinguishing signal and the arc extinguishing completion time are input from the welding power source WP. If not, the process proceeds to step 14. If input, the measurement of the elapsed time is stopped and the process proceeds to step S16.

  In step S14, the welding monitoring unit 24 determines whether or not the elapsed time at which measurement is started in step S12 exceeds the monitoring time (arc end waiting time). If not, the process returns to step S13. When exceeding, it transfers to step S15, and while outputting a stop signal to welding power supply WP, the abnormal signal that the arc end process was not normally completed is output outside.

  In step S <b> 16, the welding monitoring unit 24 sets the arc extinguishing completion time given to the arc extinguishing signal as the monitoring time. At the same time, measurement of the elapsed time from the input time of the extinguishing signal is started.

  In step S17, the welding monitoring unit 24 determines whether or not the welding release signal and the welding release completion time as the welding state signal Wc are input from the welding power source WP. If not, the process proceeds to step 18. If entered, the process proceeds to step 20.

  In step S18, it is determined whether or not a welding completion signal as a welding state signal Wc is input from the welding power source WP. Here, the reason why the input of the welding completion signal is determined is that when the welding is not confirmed, the welding completion signal is not input and the welding completion signal is input without performing the welding release processing. When the welding completion signal is not input, the process proceeds to step 19. If entered, it is assumed that welding has been completed without any problem, and this flow is terminated.

  In step S19, the welding monitoring unit 24 determines whether or not the elapsed time when the measurement is started in step S16 exceeds the monitoring time (extinguishing time). If not, the process returns to step S17. When exceeding, it transfers to step S15, and while outputting a stop signal to welding power supply WP, the abnormal signal that the arc end process was not normally completed is output outside.

  In step S20, the welding monitoring unit 24 sets the welding release completion time given to the welding release in-progress signal as the monitoring time. At the same time, measurement of the elapsed time from the input time point of the welding release signal is started.

  In step S21, it is determined whether or not a welding completion signal is input from the welding power source WP. If the welding completion signal is not input, the process proceeds to step 22. If entered, it is assumed that welding has been completed without any problem, and this flow is terminated.

  In step S <b> 22, the welding monitoring unit 24 determines whether or not the elapsed time that has started measurement in step S <b> 20 has exceeded the monitoring time (welding release completion time). If not, the process returns to step S21. When exceeding, it transfers to step S15, and while outputting a stop signal to welding power supply WP, the abnormal signal that the arc end process was not normally completed is output outside.

  As described above, in the sixth embodiment, the mutual abnormality monitoring is performed by the robot controller RC and the welding power source WP during the arc end process.

  As described above, since the robot controller RC and the welding power source WP mutually monitor each state, it is possible to prevent the manipulator M from stopping while the arc welding process is continued. .

  Further, the next process command which is a welding command signal scheduled to be output next from the robot controller RC is output, and the welding power source WP is configured to output the next process command and the actually input welding command signal. Thus, it is possible to prevent an unintended welding process from being performed due to an erroneous welding command signal being input due to an abnormality of the robot controller RC or the like. Furthermore, even if the manipulator M is performing welding while stopping, it is possible to reliably detect an abnormality.

  In addition, when outputting the welding state signal from the welding power source WP, the execution completion time scheduled for processing is output at the same time, so that the abnormality on the welding power source WP side can be detected early by monitoring on the robot controller RC side. Can be found in. Further, by applying the present invention to each welding sequence of the arc welding process, abnormality monitoring can be performed at any time during the arc welding process.

  Of the arc welding processes described above, the preflow process (Embodiment 1), the stop welding process (Embodiment 3), the crater process (Embodiment 5), and the afterflow process are performed by a welding monitoring unit of the welding power source WP. Abnormality monitoring may be performed by 44 alone.

FIG. 11 is a flowchart when abnormality monitoring is performed only with the welding power source WP.
In step S21, the welding control unit 43 determines whether or not the welding command signal Ws and the process plan information notified from the robot control device RC have been received. If received, the process proceeds to step S22. In step S22, the welding control unit 43 performs a necessary arc welding process (if the preflow start signal is received, the preflow process is started).

  In step S23, the welding monitoring unit 44 sets the processing time given to the welding command signal Ws as the monitoring time. At the same time, measurement of the elapsed time from the start of the welding process is started. The measurement start of the elapsed time may be a reception time point of the welding command signal.

  In step S24, the welding monitoring unit 44 determines whether or not the next welding command signal Ws is input. If entered, the process proceeds to normal processing. If not input, the process proceeds to step S25.

  In step S25, the welding monitoring unit 44 determines whether or not the elapsed time when the measurement is started in step S23 exceeds the monitoring time. If not, the process returns to step 24. If exceeded, the process proceeds to step S26. In step S26, the welding control unit 43 stops all the welding processes being executed.

  As described above, abnormality monitoring may be performed only by the welding monitoring unit 44 of the welding power source WP. In this case, the communication load between the robot controller RC and the welding power source WP can be reduced.

1 Welding wire 2 Base material 3 Arc 4 Welding torch 11 ROM
12 CPU
13 RAM
14 Communication interface unit 15 Drive command unit 16 Hard disk 17 Timer 18 Bus 21 Interpretation execution unit 22 Operation control unit 23 Welding command generation unit 24 Weld monitoring unit 25 Position monitoring unit 31 ROM
32 CPU
33 RAM
34 Communication interface section 35 Current / voltage detection section 36 Hard disk 43 Welding control section 44 Weld monitoring section Fc Feeding control signal Fe Crater feeding speed Fi Slow-down feeding speed Fr Feeding speed setting signal Fs Regular feeding speed Gs Gas output Signal Ie Crater welding current Is Steady welding current Iw Welding current M Manipulator Mc Operation control signal RC Robot controller Rs Position arrival signal Sa Arc confirmation signal Sp Movement speed Ss Welding speed St Welding signal Td Teaching data TP Teach pendant Va Welding release voltage Ve Crater welding voltage Vr Welding voltage setting signal Vs Steady welding voltage Vw Welding voltage Wc Welding state signal WM Wire feed motor WP Welding power supply Ws Welding command signal

Claims (11)

A manipulator holding a welding torch, a robot controller for driving and controlling the manipulator based on pre-created teaching data, and sequentially outputting a welding command signal for performing arc welding processing; and based on the welding command signal In an arc welding robot equipped with a welding power source device that performs welding control and supply of welding power,
The robot control device is a welding command generating means for outputting process plan information including a processing time related to the arc welding process, and a signal input from the welding power source device and indicating a current state of the arc welding process First monitoring means for monitoring an execution state of the arc welding process based on a welding state signal and the process plan information,
The welding power source device performs a welding control and outputs a welding state signal according to the current state, and a second monitoring for monitoring an execution state of the arc welding process based on the process plan information. And an arc welding robot. In the arc welding process with the welding torch stopped,
When the process plan information including the processing time is output by the welding command generation unit, the first monitoring unit starts measuring a first elapsed time that is an elapsed time from the output time point, and It is monitored whether or not the welding state signal corresponding to the welding command signal is input from the welding power source device until the elapsed time reaches the processing time. Output a stop signal,
When the arc control process is started by the welding control unit, the second monitoring unit starts measuring a second elapsed time that is an elapsed time from the start time, and the second elapsed time is the processing time. 2. The arc welding robot according to claim 1, wherein whether or not the next welding command signal is input until the time of reaching is reached is monitored, and if not input, the arc welding process being executed is stopped. . The welding command generation means outputs, as the process plan information, a next process command indicating a welding command signal scheduled to be output in the next process, in addition to the processing time.
The arc welding robot according to claim 2, wherein the next welding command signal is a welding command signal indicated by the next process command. The welding control means gives an execution completion time, which is a time required for the arc welding process during the process, to the welding state signal and outputs it,
When the welding state signal including the execution completion time is input from the welding control unit, the first monitoring unit starts measuring a third elapsed time that is an elapsed time from the input time point, and It is monitored whether or not the next welding state signal is input from the welding power source until the elapsed time reaches the execution completion time. If not, an emergency stop signal is output to the welding power source. The arc welding robot according to claim 2, wherein the arc welding robot is provided. The robot controller is configured to calculate a position of the welding torch for each predetermined period based on the teaching data, and an arrival signal that outputs a position arrival signal when the welding torch reaches the calculated position. And an output means,
During steady welding while moving the welding torch, the welding control means outputs a welding signal as the welding state signal at a predetermined cycle,
The first monitoring means monitors whether or not the welding signal is input at every predetermined period, and if not input, outputs an emergency stop signal to the welding power source device,
The said 2nd monitoring means monitors whether the said position arrival signal is input within the predetermined arrival signal waiting time, and when not input, stops the said regular welding. Arc welding robot. At the time of the preflow process in which the shield gas output is started in advance by a predetermined preflow time,
The welding command generating means outputs a preflow start signal including the preflow time as the processing time,
When the output of the shield gas is started by the welding control means, the second monitoring means starts measuring the second elapsed time that is an elapsed time from the start time, and the second elapsed time is 2. The output of the shield gas is stopped if it is monitored whether or not an arc start signal is input from the robot controller until the preflow time is reached. Arc welding robot. At the time of the preflow process in which the shield gas output is started in advance by a predetermined preflow time,
The welding command generating means outputs a preflow start signal including the preflow time as the processing time and an arc start command as the next process command,
When the preflow start signal is output, the first monitoring unit starts measuring the first elapsed time that is an elapsed time from the output time until the first elapsed time reaches the preflow time. During this period, it is monitored whether or not a preflow start completion signal as the welding state signal is input from the welding power supply device. And
When the output of the shield gas is started based on the preflow start signal, the second monitoring means starts measuring the second elapsed time that is an elapsed time from the start time, and the second elapsed time Whether or not the arc start signal indicated by the next process command is input until the preflow time is reached, and if not input, the output of the shielding gas is stopped. The arc welding robot according to claim 3. During arc start processing that generates arcs,
The welding command generating means outputs an arc start signal including an arc start failure detection time as the processing time,
When the arc start signal is output, the first monitoring means starts measuring the first elapsed time that is an elapsed time from the output time, and the first elapsed time is set to the arc start failure detection time. Monitoring whether or not the welding state signal is input from the welding power supply device every predetermined period until it reaches, if not, output an emergency stop signal to the welding power supply device,
When the ignition process is started based on the arc start signal, the second monitoring unit starts measuring the second elapsed time that is an elapsed time from the start time of the ignition process, and Monitor whether or not an arc is generated instead of the next welding command signal until the elapsed time reaches the arc start failure detection time, and stop the ignition process if no arc occurs. The arc welding robot according to claim 2. During crater processing to form the weld end,
The welding command generation means outputs a crater welding signal including a crater welding time as the processing time,
When the output of the welding power is changed based on the crater welding signal, the second monitoring means measures the first elapsed time, which is an elapsed time from the change of the welding power output, and the first elapsed time. 2. The arc welding robot according to claim 1, wherein if the arc end signal is not input from the robot controller even if the time exceeds the crater welding time, the crater welding is stopped. During crater processing to form the weld end,
The welding command generation means outputs a crater welding signal including a crater welding time as the processing time and an arc end command as the next process command,
When the crater welding signal is output, the first monitoring means starts measuring the first elapsed time that is an elapsed time from the output time point, and the first elapsed time reaches the crater welding time. Until whether or not a crater welding start signal as the welding state signal is input from the welding power source device, and if not input, an emergency stop signal is output to the welding power source device,
When the output of the welding power is changed based on the crater welding signal, the second monitoring means measures the second elapsed time, which is an elapsed time from the change in output of the welding power, and the second elapsed time. Whether or not the arc end signal indicated by the next process command is input before the time reaches the crater welding time is monitored, and if not input, the crater welding is stopped. The arc welding robot according to claim 3. During arc end processing to stop the arc,
The welding command generating means outputs an arc end signal including an arc end waiting time as the processing time,
The welding control means outputs an arc extinguishing signal and the execution completion time as the welding state signal when the arc extinguishing process is started based on the arc end signal, and then proceeds to the welding release process when the process proceeds to the welding release process. A welding release signal as a welding state signal and the execution completion time are output, and when all arc end processing is completed, an arc end completion signal is output as the welding state signal,
The first monitoring means measures the first elapsed time which is an elapsed time from the output time of the arc end signal,
When the arc extinguishing signal or the welding release is not input, it is monitored whether the arc end completion signal is input before the first elapsed time reaches the arc end waiting time, If not input, an emergency stop signal is output to the welding power source,
When the arc extinguishing signal or the welding release signal is input, the measurement of the first elapsed time is stopped and the elapsed time from the input time of the arc extinguishing signal or the welding release signal is When re-measurement is started as one elapsed time, and it is monitored whether or not the next welding state signal is input before the re-measured first elapsed time reaches the execution completion time. Outputs an emergency stop signal to the welding power source,
When the arc extinguishing process is started based on the arc end signal, the second monitoring unit starts measuring the second elapsed time, which is an elapsed time from the process start time, and the second elapsed time. Monitor whether or not a shield gas stop signal is input from the robot controller until the arc end waiting time is reached, and if not, output an abnormal signal to the robot controller The arc welding robot according to claim 4.

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