JP6029967B2 - Arc welding robot system - Google Patents

Description

  The present invention relates to an arc welding robot system.

  In recent labor-saving or unmanned arc welding lines, all welding data (command values and actual values) are recorded securely for each welded part of each welding workpiece, and the subsequent It is important in quality control to ensure so-called traceability so that it can be traced to a certain level. In the arc welding line described above, in order to increase production efficiency, a plurality of arc welding robots often perform welding work simultaneously on one welding workpiece. In such a case, in order to ensure traceability, it is necessary to centrally manage the welding operation data of all arc welding robots that simultaneously performed arc welding.

  Also, in arc welding with an arc welding robot, if welding abnormalities such as arc breakage or welding, or poor work such as poor penetration or welding beads occur, the welding phenomenon in a minute time domain is analyzed in order to investigate the cause. There are many things to do. In this case, at the portion where the phenomenon occurs, at least an actual welding current and an actual welding voltage sampled at a high frequency are required. In addition to these, additional information such as the actual wire feed speed and actual gas flow rate is effective for investigating the cause.

  Patent Document 1 proposes an arc welding monitor in which waveform data and an operation trajectory of a robot are stored in synchronization by a welding current, welding voltage, and various sensors during arc welding and displayed on a display. In this monitor device, welding abnormality determination can also be performed, and the display color is changed in the portion where abnormality has occurred. Moreover, in patent document 1, the detection means of a welding current and a welding voltage is installed outside the robot control apparatus and outside the arc welding machine.

  Patent Document 2 discloses an arc welding robot that can store measurement data such as a welding current output average value and welding voltage output average value during arc welding as history information together with a program name and a welding location. In Patent Document 2, since it is an average value between the teaching steps of the welding current and the welding voltage that can be stored as a history, there is an advantage that the storage capacity of the storage device can be reduced. Here, the history timing can be selected from when all welding conditions are changed or when an abnormality occurs.

  Patent Document 3 discloses a technique for collecting and displaying waveform data during welding work by an arc welding robot alone without using an external device. In the technique of Patent Document 3, the collected data is stored in a RAM built in the control device of the arc welding robot or an external memory connected to the teach pendant.

Japanese Patent Laid-Open No. 11-58007 JP 2006-26655 A JP 2006-26640 A

However, Patent Document 1 has the following problems (1) and (2).
(1) When welding is performed simultaneously on a single workpiece by a plurality of arc welding robots, it is necessary to manage the construction data of all the welding robots centrally in order to ensure traceability. However, with the technique of Patent Document 1, it is possible to monitor construction data of individual arc welding robots, but it is not possible to centrally manage data of a plurality of arc welding robots.

  (2) In the technique of Patent Document 1, waveform data sampled at the same frequency is stored as a history for all welding operations. For this reason, when sampling is performed at a high frequency, a large-capacity nonvolatile memory device that can be accessed at high speed is required for each robot control device, and the system becomes very expensive.

Also in patent document 2, there exists a problem of said (1).
In Patent Document 3, it is not necessary to provide detection means outside the robot controller and the arc welder, but there are problems (1) and (2) above.

  It is an object of the present invention to reliably store monitor related information including monitor values and command information to ensure traceability in a robot system that allows a plurality of robots to perform work on one workpiece, and to manage them centrally. Another object of the present invention is to provide an arc welding robot system that can also be used.

  In order to solve the above problems, an arc welding robot system includes a monitor device, a plurality of robot control devices that respectively control a plurality of arc welding robots, and a robot control device provided for each of the robot control devices. In an arc welding robot system in which a plurality of welding machines that supply a welding current to a welding torch of an arc welding robot to be controlled according to command information related to welding from the robot controller are connected via a common network, The robot control device transmits process section information relating to the welding work process to the monitor device at the start and end of the welding work process, and each time the execution state changes during the welding work process, A transmission unit for transmitting execution state information (hereinafter referred to as execution state information) to a welding machine to be controlled; Each of the welding machines includes a storage unit that stores the monitor value acquired during the welding operation process, the command information, and the execution state information (hereinafter referred to as acquisition information) in time series, and the storage unit A welding machine transmitter for transmitting the acquired information stored in the monitor device to the monitor device, wherein the monitor device includes the process section information transmitted from each robot control device and the acquired information transmitted from each welder. A monitor storage unit for storing a time stamp is provided.

  The transmission unit of each robot control device transmits an ID code of a transmission source to the monitor device at the time of transmission of the process section information, and each welding machine uses the ID code of the transmission source as the acquisition information. It is preferable to give and transmit to the monitor device.

  The welding machine transmission unit performs communication while reducing the amount of data transmitted per unit time during the welding operation process, and increases the amount of data transmitted per unit time after the welding operation process. preferable.

  In addition, the welding machine includes a control unit that controls a welding power source that supplies the welding current and controls the welding machine transmission unit, and the welding machine transmission unit is configured to perform back-up by the control unit during the welding operation process. Communication is performed by ground processing and communication is performed by foreground processing by the control unit after the welding operation process, and the control unit sets the load in the foreground processing to be larger than the load in the background processing. It is preferable to cause the transmission unit to perform communication.

  According to this robot system, in a robot system that allows multiple robots to work on one workpiece, monitor-related information including monitor values and command information can be reliably saved to ensure traceability and centralized management There is also an effect that can be done.

The network figure of the arc welding robot system of one embodiment. The electric block diagram of a robot control apparatus, a welding machine, and a monitor apparatus. The flowchart of the monitor processing program which a robot control apparatus performs. The flowchart of the monitor processing program which a welding machine performs. Explanatory drawing of a work program. The network figure of the arc welding robot system of other embodiments.

Hereinafter, an embodiment in which the present invention is embodied in an arc welding robot system will be described with reference to FIGS.
As shown in FIG. 1, the arc welding robot system 10 includes a plurality of robots R1 to RN configured to perform arc welding, robot control devices RC1 to RCN that control each robot, and a monitor device PC.

  Since the robots R1 to RN controlled by the robot controllers RC1 to RCN (N = 1, 2,...) Are respectively known articulated robots, they will be briefly described. The manipulator constituting the robot is composed of a base member fixed to an appropriate place such as a floor, a plurality of arms connected to the base member via a plurality of joints, and a drive motor (not shown) that drives each arm. Yes. The drive motor includes a rotary encoder (not shown) and can detect the current position of the drive motor. A welding torch (not shown) that performs arc welding on a workpiece (not shown) that is a workpiece is attached to the tip of the wrist at the tip of the manipulator.

  Also, a teach pendant (not shown) and a welding machine Y1 to YN for an operator to operate each robot R1 to RN and a welding machine Y1 to YN are connected to each robot control device RC1 to RCN.

  As shown in FIG. 1, the robot control devices RC <b> 1 to RCN, the welding machines Y <b> 1 to YN, and the monitor device PC are connected to each other via a wired network 20. The network 20 is composed of, for example, LAN Ethernet (registered trademark). Note that the network 20 is not limited to LAN Ethernet, and may be configured by other networks.

  The network 20 can perform information communication and control command communication. For example, communication for exchanging information between robot control devices, communication for exchanging information between welding machines, information communication between a robot control device and a monitoring device PC, and a robot control device and a welding machine to be controlled Communication is possible.

(Robot controller)
Next, a robot control device and a welding machine will be described. Since the robot controllers RC1 to RCN have the same configuration, the configuration of the robot controller RC1 will be described as a representative.

  As shown in FIG. 2, the robot controller RC1 includes a CPU (Central Processing Unit) 11, a ROM 12, a RAM 13, a network communication unit 14, a storage device 15, a main control unit 16, and the like. Are connected to each other.

  The ROM 12 stores a system program for the control device itself. The RAM 13 is a volatile memory and serves as a work memory when executing various programs such as a work program described later. The network communication unit 14 communicates with other robot control devices RC2 to RCN and the monitor device PC via the network 20. The network communication unit 14 corresponds to a transmission unit.

  The storage device 15 is a readable / writable memory, and includes, for example, a hard disk, a semiconductor memory, and the like. The storage device 15 stores a robot work program and monitor-related information described later.

  The main control unit 16 analyzes a trajectory plan and an interpolation operation by a known method based on an analysis unit 16a that analyzes each teaching step of a work program (described later) taught by a teach pendant (not shown) and an analysis report analyzed by the analysis unit 16a. And an execution unit 16b that generates a control value based on current position information from the rotary encoder (not shown) provided at the joint of the manipulator. The execution unit 16b controls the rotation of driving motors (not shown) provided at the joints of the manipulator via the servo driver (not shown) to move the welding torch at the wrist part of the manipulator.

(Example of work program)
FIG. 5 shows an example of the work program. In the work program shown in FIG. 5, a work program number, a work number, and a plurality of teaching step numbers 001 to n are described. The workpiece number is information for identifying workpieces that are simultaneously processed by the plurality of robots R1 to RN, and is information that is assigned by the user so as to be easily identified.

  The work number may be stored in the work program as shown in the figure, but the work program number and the work number are associated with each other by means of a table or the like and stored in the storage device 15 or the work program is stored in the work program. The work number may be determined by another means such as inputting a work number for each work using a teach pendant (not shown) before starting. Further, as information for identifying a workpiece, other identification information such as an ID composed of a name or alphabet may be used instead of the above-described workpiece number. In the following description, it is assumed that the work number is stored in the work program.

  A teaching step 004 illustrated in FIG. 5 is a teaching step for starting welding, in which a welding start command is described. Similarly, a teaching step 008 illustrated as an example is a teaching step for ending welding, in which a welding end command is described.

  In the teaching step 004 in which the welding start command is described, a welding current, a welding voltage, and a moving speed (speed command) (200 A, 18.0 V and 50 cm / min in the example of FIG. 5 respectively) are further described. . Here, the welding current, the welding voltage, and the moving speed (speed command) described together with the welding start command are examples of welding conditions when welding is started.

  In the teaching step 008 in which a welding end instruction is described, a welding current and a welding voltage (180A, 17.0V in the example of FIG. 5) are further described. It is an example of the welding conditions when the welding current described with the said welding completion command and the welding voltage are welding completion.

  In teaching steps 001 to 003, a positioning command and a moving speed (speed command) are described. In teaching steps 005 to 007, a linear interpolation command and a moving speed are described. In the teaching step in which the movement command is described, the teaching point is stored in the storage device 15.

  The positioning command and the linear interpolation command are examples of movement commands. Although not shown in the example of FIG. 5, the movement command includes a circular interpolation command and the like in addition to the positioning command and the linear interpolation command. In the teaching step in which these movement commands are described, the moving speed of the welding torch when moving to the teaching point of the teaching step is also described as shown in FIG.

  Here, in the teaching step of the work program, arc welding is performed between the teaching point in the teaching step in which the welding start command is described and the teaching point in the teaching step in which the welding end command is described. The work process performed in step 1 corresponds to the welding work process.

(Welder)
Next, returning to FIG. 2, the welding machine will be described. Since the configurations of the welders Y1 to YN are the same, the configuration of the welder Y1 will be described as a representative.

  The welding machine Y1 includes a CPU (central processing unit) 21, a ROM 22, a RAM 23, a network communication unit 24, a welding control unit 25, and the like, and the respective units are connected to each other via a bus (not shown).

  The welding machine Y1 includes a welding power source 28. The welding power source 28 includes a digital inverter control circuit (not shown), and precise welding current waveform control is performed on the commercial power source (for example, three-phase 200 V) input from the outside with a high-speed response by the inverter control circuit. That is, the output side of the welding power source 28 supplies a welding voltage between the welding torch and the workpiece via a power cable (not shown).

  The CPU 21 performs control of each part of the welding machine Y1 and wire feeding control of a welding wire feeding device that supplies a welding torch (not shown). For example, when receiving a welding start command from the robot controller RC1, the CPU 21 controls the welding control unit 25 based on the welding start command. Further, the CPU 21 controls the network communication unit 24. The ROM 22 stores control software for controlling the operation of the welding control unit 25 (or the welding power source 28) included in the welding machine Y1 and a wire feeding device (not shown). The RAM 23 is a volatile memory, and provides a work area to the CPU 21. Calculation data, various data (command information related to welding, execution state information) received from the robot controller RC1, monitor values, etc. Is temporarily stored.

  The welding control unit 25 controls the welding power source 28 according to the welding conditions transmitted from the robot controller RC1 to supply a welding current to the welding torch. The network communication unit 24 can communicate with the robot control device RC1 and the monitor device PC via the network 20. The network communication unit 24 corresponds to a welding machine transmission unit.

  The output side of the welding power source 28 includes a current detection unit 26 and a voltage detection unit 27. The current detection unit 26 detects a welding current flowing in a welding wire (not shown). The voltage detection unit 27 detects a welding voltage applied between the tip of the welding wire (not shown) and the workpiece. Data detected by the current detection unit 26 and the voltage detection unit 27 (that is, welding current and welding voltage) is detected at the same sampling period as a monitor value and stored in the RAM 23. The RAM 23 corresponds to a storage unit.

(Monitor device)
Next, the monitor device PC will be described. The monitor device PC is composed of a computer and includes a CPU (Central Processing Unit) 31, a ROM 32, a RAM 33, a storage device 34, a network communication unit 35, and the like. The CPU 31 controls the system of the monitor device PC itself. The ROM 32 stores a system program of the monitor device itself. The RAM 33 is a volatile memory and serves as a working memory when executing various programs. The storage device 34 is a readable / writable memory, and includes, for example, a hard disk, a semiconductor memory, a magnetoresistive RAM, and the like. In the case where the storage device 34 is a semiconductor memory, a non-volatile memory that does not require a backup power supply is preferable. However, the storage device 34 is not limited and may be a semiconductor memory that requires a backup power supply. The storage device 34 corresponds to a monitor storage unit.

  The network communication unit 35 communicates with the robot control devices RC1 to RCN and the welding machines Y1 to YN via the network 20. The network communication unit 35 corresponds to a communication unit. The output device 50 is connected to the monitor device PC. The output device 50 is composed of, for example, a display device or a printer.

(Operation of the embodiment)
The operation of the arc welding robot system configured as described above will be described with reference to the flowcharts of FIGS. Since the monitoring processes of the robot control devices RC1 to RCN are the same, and the monitoring processes of the welding machines Y1 to YN are the same, the monitoring processes executed by the robot control device RC1 and the welding machine Y1 will be described below. To do.

(Monitoring process of robot controller)
FIG. 3 is a flowchart of a monitor processing program executed by the main control unit 16 of the robot controller RC1, and the monitor processing program is configured to control a manipulator and a welding machine Y1 (not shown) based on the work program. Processed by task. Since a process for interpreting a work program and outputting various command signals for controlling the manipulator and the welding machine Y1 is known, the description of this process will be omitted, and a monitor performed in parallel with this process will be described below. Only the processing contents of the processing program will be described. More specifically, the monitor-related processing that is executed by the execution unit 16b of the main control unit 16 during welding start and welding end and during welding will be described. In the following description, for the sake of convenience of explanation, “step” in the flowcharts of FIGS. 3 and 4 is denoted by S, and “teach step” of the work program is not denoted by S.

  (Step S1) In S1, it is determined whether or not the execution of the work program is completed. When the execution of the work program has been completed, the processing of this flowchart is terminated, and when the execution of the work program has not been completed, the process proceeds to S2.

  (Step S2) In S2, it is confirmed whether or not the command to be executed at the command execution timing is a welding start command. If the command is not a welding start command, the process returns to S1, and if it is a welding start command, the process proceeds to S3.

  (Step S3) In S3, the work number described in the work program and a start trigger for starting welding are notified to the monitor device PC. At this time, the transmission source ID code is assigned and notified.

The start trigger transmitted from the robot controller RC1 to the monitor device PC corresponds to process section information.
(Step S4) In S4, the execution part 16b confirms whether welding was complete | finished. When welding is not completed, the process proceeds to S6, and when welding is completed, the process proceeds to S5.

  (Step S5) In S5, the ID code of the transmission source is added to the end trigger indicating that the welding has ended, and the monitor apparatus PC is notified, and the process returns to S1. Here, the end trigger transmitted from the robot controller RC1 to the monitor device PC corresponds to the process section information.

  (Step S6) In S6, the execution unit 16b switches the work program currently being executed to another work program number in the welding section, or changes the teaching step number of the work program currently being executed in the welding section. To see if

  The welding section is between a teaching point at a teaching step number in which a welding start command is described and a teaching point at a teaching step number in which a welding end command is described. In the example of the work program in FIG. 5, a welding section is a portion between the teaching point at the teaching step number 004 of the welding start command and the teaching point at the teaching step number 008 of the welding end command. Therefore, the teaching step number of the welding section is switched as execution in the welding section proceeds.

  The work program number is switched based on the program number described together with the program call command when there is a program call command in the welding section in the work program currently being executed.

  If the work program number or teaching step number is switched in S6, the process proceeds to S7, and if the work program number or teaching step number is not switched, the process proceeds to S8.

  (Step S7) In S7, the execution unit 16b gives the ID code of the transmission source to the work program number after switching or the teaching step number and notifies the welding machine Y1. Thereafter, the process proceeds to S8.

  In FIG. 3, when the welding start command is first determined as “YES” in S2, “NO” in S4, and “YES” in S6, the welding start command is switched to the teaching step described. Therefore, the work program number and teaching step number in which this welding start instruction is described are notified to the welding machine Y1 as execution state information (hereinafter referred to as execution state information). Moreover, the welding start command and welding conditions described in this teaching step are transmitted to the welding machine Y1 as command information related to welding.

  In the case where the process returns from S8 or S9 described later to S4, “NO” in S4, “YES” in S6, and the process of S7 is performed, and new welding conditions are described in the teaching step. The new welding condition is transmitted to the welding machine Y1 as command information related to welding.

  The reason for notifying the work program number or the teaching step number after switching to the welding machine Y1 instead of the monitoring apparatus PC will be described in detail with reference to the flowchart of FIG. 4, but from the welding machine Y1 to the monitoring apparatus PC. This is because the postscript acquisition information is not necessarily transmitted in real time.

  In addition, in order to accurately correspond the work program and the teaching step with the monitor value being executed, which will be described later, information on the switching of the work program number and the execution state of at least one of the teaching steps is notified. In the welder Y1, the notified execution state information is stored in the RAM 23 in time series together with a monitor value to be described later.

  (Step S8) In S8, the execution part 16b confirms whether abnormality has generate | occur | produced. If an abnormality has occurred, the process proceeds to S9, and if no abnormality has occurred, the process returns to S4. Here, the abnormality is an abnormality detected when, for example, a welding operation abnormality such as an arc break or a welding torch interferes with a jig or a workpiece. The detection of these abnormalities is performed by detection of the arc break by the current detection unit 26 of the welding machine Y1, and is notified by communication from the welding machine Y1 via the network 20. Further, since the interference with the jig or workpiece caused by the welding torch can be detected by a known method during control by the robot controller RC1, the description thereof is omitted.

(Step S9) In S9, the execution unit 16b adds the ID code of the transmission source to the detected abnormality content and transmits it to the monitor device PC, and returns to S4.
(Monitoring process of welding machine)
Next, the monitoring process of the welding machine Y1 will be described with reference to the flowchart of FIG.

  FIG. 4 is a flowchart of a monitor processing program executed by the CPU 21 of the welding machine Y1, and when the robot control device RC1 executes the work program, the monitor processing program is executed in response to an input of an activation signal from the robot control device RC1. It is activated.

  (Step S100) In S100, CPU21 confirms whether the welding start command from robot control apparatus RC1 was received. If a welding start command has not been received, the process jumps to S109, and if a welding start command has been received, the process proceeds to S101.

  (Step S101) In S101, the CPU 21 assigns the ID code of the transmission source to the received welding conditions and welding start command and notifies the monitor device PC, and then proceeds to S102. Note that the notification of the welding start command to the monitor device PC may be omitted because the welding control command is also notified from the robot controller RC1. However, it is preferable to notify the welding start command from the welding machine Y1 because it is possible to check whether or not the same welding start command is notified from both the robot controller RC1 and the welding machine Y1 in the monitor device PC.

  (Step S <b> 102) In S <b> 102, the CPU 21 confirms whether or not the data sampling timing is reached. If the data sampling timing is reached, the process proceeds to S <b> 103. If the data sampling timing is not reached, the process proceeds to S104. Note that the sampling timing is measured by a timer counter (not shown) provided in the welding machine Y1, and when the time preset by the operator has elapsed from the previous sampling timing, the CPU 21 determines that the sampling timing has come. It is.

  (Step S103) In S103, the CPU 21 samples (measures) the welding current and the welding voltage by the current detection unit 26 and the voltage detection unit 27, stores them in the RAM 23 in the order of sampling, and then proceeds to S104. In this embodiment, the welding current and welding voltage obtained by measurement are used as monitor values.

  (Step S104) In S104, it is confirmed whether or not the transmission timing to the monitoring device PC has come. If it is the transmission timing, the process proceeds to S105, and if it is not the transmission timing, the process proceeds to S106. . Note that the transmission timing is measured by a timer counter (not shown) provided in the welding machine Y1, and when the time preset by the operator has elapsed from the previous transmission timing, the CPU 21 determines that the transmission timing has been reached. It is.

  (Step S <b> 105) In S <b> 105, the CPU 21 transmits the specified capacity for each unit time from the data stored in the RAM 23 in the order of storage, that is, from the old data to the monitor device PC with the ID code of the transmission source. After that, the process proceeds to S106. In step S105, the CPU 21 deletes the data that has been transmitted from the RAM 23.

  The data stored in the RAM 23 at the stage of the processing of S105 is the monitor value stored in the S103, the data stored in the RAM in S107 described later (that is, the data stored in the RAM 23 in S107 after returning from S108 to S102 previously). Data). The monitor value and data (execution state information and command information related to welding) stored in the RAM 23 in S107 described later correspond to acquired information.

  What is characteristic in this embodiment is that the CPU 21 performs complicated control of the welding control unit 25 during arc welding, and therefore data transmission to the monitor device PC that needs to be performed in parallel with this control ( The transmission per unit time at the time of transmission is performed so as to reduce the load of the processing of S105, that is, the amount of data transmitted in S105 is smaller than the amount of data transmitted to the monitor apparatus PC in S110 described later. The data is limited to the specified capacity. The advantages of doing this will be described later.

  (Step S106) In S106, the CPU 21 confirms reception of a work program number (execution state information), a teaching step number (execution state information), or command information (welding conditions) related to welding from the robot controller RC1. If at least one of the work program number, the teaching step number, or the command information (welding conditions) related to welding is received, the process proceeds to S107, and if there is no reception, the process proceeds to S108.

(Step S107) In S107, the CPU 21 stores the data (information) received in S106 in the RAM 23, and then proceeds to S108.
(Step S <b> 108) In S <b> 108, the CPU 21 receives a welding end command from the robot controller RC <b> 1 and confirms whether or not the arc control process has been executed by the welding control unit 25. When the arc end process is not executed, the CPU 21 returns to S102, and when the arc end process is executed, the process proceeds to S109. When the arc end process is being performed, the welding current is 0. Therefore, by confirming the welding current, the CPU 21 can confirm the execution of the arc end process.

  Here, the reason for returning to S102 is that arc welding is not completed during the time from the reception of the welding end command to the completion of the arc end process. When the process returns to S102, the processes of S102 to S107 are executed. Therefore, the monitor value sampled during the period from the welding end command to the arc end process is stored in the RAM 23 in S103.

  (Step S109) In S109, the CPU 21 checks whether or not the stored data, that is, the acquisition information remains in the RAM 23. If the acquisition information remains, the process proceeds to S110, and the acquisition information does not remain. Return to S100.

  (Step S <b> 110) In S <b> 110, the CPU 21 transmits all acquisition information remaining in the RAM 23 after the arc end process to the RAM 23 with the transmission source ID code added to the monitor device PC. Thereafter, all acquired information remaining in the RAM 23 is cleared.

  What is characteristic in the present embodiment is that the CPU 21 does not perform complicated control of the welding control unit 25 based on the welding start command in the transmission to the monitor device PC after the end of the arc end. The amount of data to be transmitted is increased from S105, that is, the amount of data to be transmitted per unit time at the time of transmission is increased from the specified capacity.

  As described above, in this embodiment, in S105, the amount of data transmitted to the monitoring apparatus PC during arc welding is limited to a specified capacity. However, the sampling frequency of the monitor value in S103 during the welding operation is temporarily set. If it is high, there are the following problems.

  If the sampling frequency of the monitor value in S103 is increased, it is necessary to increase the data amount of the monitor value transmitted to the monitor device PC. Along with this, it is necessary to increase the load of communication processing for controlling the network communication unit 24 of the CPU 21, but during the welding operation, the CPU 21 controls the welding control unit 25, a welding wire feeding device (not shown), and the like. Therefore, the processing capacity that can be allocated for the communication processing is limited. If the acquisition information (execution state information and monitor value) acquired during all welding operations is to be transmitted to the monitor device PC in real time, the sampling frequency is lowered so that the processing capacity of the CPU 21 is not exceeded. This reduces the amount of data transmitted to the network.

  On the other hand, in this embodiment, in S105, the amount of data at the time of transmission to the monitor device PC during arc welding is limited to a specified capacity, and the load is suppressed so as not to exceed the processing capacity of the CPU 21. The acquired information that cannot be transmitted during arc welding is temporarily stored in the RAM 23, and the load of the CPU 21 released from the various processes during arc welding after the end of arc welding (that is, after the end of arc welding). The acquisition information (execution state information and monitor value) that could not be transmitted during arc welding is transmitted. For this reason, the sampling frequency of the monitor value in S103 can be increased, and the storage capacity of the RAM 23 for temporarily storing the acquired information is also stored in the RAM 23 so that the acquired information is temporarily stored. Compared with the case of sending to the monitor device PC collectively after the end (after the end of the arc end), it can be reduced, and the transmission time of the acquisition information to the monitor device PC after the end of the welding (after the end of the arc end) Can also be shortened.

(Processing of monitor device PC)
The CPU 31 of the monitor device PC has process section information (welding start command, welding end command) and acquired information (execution state information and monitor value) from all connected robot control devices RC1 to RCN and welding machines Y1 to YN. ) Via the network communication unit 35, the ID code of the transmission source given to the received process section information and acquisition information, and the time stamp by a timer (not shown) at the time of reception as metadata in the acquisition information, respectively. The data is assigned and stored in the storage device 34 for each robot control device and each welding machine.

  Therefore, in this embodiment, from the process section information and the acquisition information stored in the storage device 34, the process section information having the same work number in the same time zone and the source ID code are extracted, If the time stamps are arranged in order, each becomes data in the order of time when welding is performed by a plurality of arc welding robots. In addition, since the workpiece information is used, if the workpiece information and the ID code of the transmission source are extracted and arranged in order by time stamps, each becomes data in the order of time when welding is performed by a plurality of arc welding robots. .

  Further, as described above, the acquired information is not transmitted from the welding machine Y1 to the monitor device PC in real time, but the changed work program number and teaching step number are executed each time the work program number and teaching step number change. The information is transmitted from the robot controller RC1 to the welding machine Y1 as information, and is stored in the RAM 23 of the welding machine Y1 as execution state information in time series together with the monitor value, so that the correspondence between the monitor value and the welding site can be accurately determined. You can also do it.

The arc welding robot system of this embodiment has the following features.
(1) The arc welding robot system of this embodiment is provided for each of the monitor device PC, the plurality of robot control devices RC1 to RCN that respectively control the plurality of arc welding robots R1 to RN, and the robot control devices RC1 to RCN. A common network 20 includes a plurality of welding machines Y1 to YN that supply a welding current to a welding torch of an arc welding robot to be controlled in accordance with command information related to welding from the robot controllers RC1 to RCN during the welding operation process. Connected through. And each robot control apparatus RC1-RCN transmits the process division information regarding the said welding operation process with respect to the monitor apparatus PC at the time of the start and completion | finish of a welding operation process, respectively, and an execution state changes during a welding operation process. Every time, the network communication part 14 (transmission part) which transmits execution state information to the welding machine of control object is provided.

  Each of the welding machines Y1 to YN includes a RAM 23 (storage unit) that stores the monitor value acquired during the welding operation process, the command information, and the execution state information (hereinafter referred to as acquisition information) in time series, The network communication part 24 (welding machine transmission part) which transmits the acquisition information memorize | stored in RAM23 to monitor apparatus PC is provided. In addition, the monitor PC stores a storage device 34 (monitor storage unit) that stores the process section information transmitted from the robot controllers RC1 to RCN and the acquired information transmitted from the welders Y1 to YN with a time stamp. ). As a result, according to the present embodiment, in a robot system that allows a plurality of robots to perform work on one workpiece, monitor related information including monitor values and command information can be reliably stored to ensure traceability. , It can also be centrally managed. Further, according to the present embodiment, traceability of welding results can be ensured in an arc welding robot system that welds one workpiece using a plurality of arc welding robots.

  Furthermore, it is not necessary to provide a large-capacity storage (nonvolatile memory) for storing the history of execution state information and acquired information for each robot control device (or welder), and a system can be constructed at low cost. Further, the large-capacity storage may not use an expensive large-capacity storage (nonvolatile memory) capable of high-speed access. In addition, monitor values sampled at a high frequency can be acquired and stored as a history without using a large-capacity storage that can be accessed at high speed but is expensive. That is, data necessary for analyzing a welding phenomenon in a minute time domain can be acquired.

  Also, if the welding machine is a digital welding machine, it is possible to use the current detection unit and voltage detection unit built in the digital welding machine, and a current / voltage detector can be installed outside the robot controller and welding machine. Compared with the case where it is provided, the system is inexpensive, and the setup and maintenance are also simplified.

  (2) In the arc welding robot system of the present embodiment, the network communication unit 14 (transmission unit) of each of the robot control devices RC1 to RCN transmits the ID code of the transmission source via the network 20 together with the transmission of the process section information. It transmits with respect to monitor apparatus PC, and each welding machine Y1-YN attaches ID code of a transmission source, and transmits with respect to monitor apparatus PC. As a result, according to the present embodiment, if the ID codes of the transmission sources in the same time zone are extracted and arranged in order by time stamp, the data in the order of time in which welding is performed by a plurality of arc welding robots. It can be.

  (3) In the arc welding robot system of the present embodiment, the network communication unit 24 (welder transmission unit) performs communication by reducing the amount of data transmitted per unit time during the welding operation process, and the welding operation process. After that, the amount of data transmitted per unit time was increased. As a result, the sampling frequency of the monitor value can be increased, and the storage capacity of the RAM 23 (storage unit) for temporarily storing the acquired information is also stored and saved in the RAM 23. This can be reduced compared to the case where the welding is completed (after the end of the arc end) and is transmitted to the monitor device PC at the same time, and the acquired information is transmitted to the monitoring device PC after the end of the welding (after the end of the arc end). Time can be shortened.

In addition, this invention is not limited to the said embodiment, You may comprise as follows.
-In the flowchart of FIG. 4, when sampling a welding current and a welding voltage (monitor value) by S103, it is good also as an arithmetic mean value of a preset period, or a moving average value.

  In the flowchart of FIG. 4, in order to reduce the load during arc welding of the CPU 21, a method of performing communication with a specified capacity every unit time in S <b> 105 is used. This may be performed by so-called background processing in which communication is performed using the free time of the CPU 21 in S105. For example, in S105, if there is data recorded in the RAM 23, the process of reading it and sending it to the monitor PC is a separate task (or thread), and other processes such as a welding control process and a welding current / voltage sampling process. Lower the execution priority. In S110, if there is data recorded in the RAM 23, foreground processing is performed to increase the load on the CPU 21 and perform large-capacity communication. In this case, the CPU 21 corresponds to a control unit.

  As shown in FIG. 6, the configuration of the arc welding robot system 10 may be separated into a command network 20A that requires high real-time performance and an information network 20B that may have low real-time performance. . The information-related network 20B may be a wireless network. In the network 20A, communication of control commands (various commands) is performed between the robot controller and the welding machine. In the network 20B, information communication between the robot control devices RC1 to RCN and the monitor device PC and information communication between the welding machines Y1 to YN and the monitor device PC are performed.

  In each of the above embodiments, the monitor value is the welding current and the welding voltage, but the monitor value is not limited to the welding current and the welding voltage. For example, although not shown, a sensor for detecting a wire feed speed by a wire supply device that supplies a welding wire to the welding torch is provided, and the wire feed speed is used as a monitor value, or welding is performed from the welding torch during arc welding. The gas flow rate per unit time of the shield gas discharged to the construction site may be the monitor value.

・ As the monitor value, only welding current or welding voltage may be used.
・ As the monitor value, the welding current and the wire feed rate are set, or the welding voltage and the shield gas flow rate are set, or the welding voltage and the wire feed rate are set, or the welding voltage and the shield gas flow rate are set. Or the welding current, the wire feed rate and the shield gas flow rate, or the welding voltage, the wire feed rate and the shield gas flow rate, or the welding current, the welding voltage, and the wire feed rate. And the shielding gas flow rate.

  In the embodiment, the work identification number (work information) is transmitted to the monitor device PC together with the process section information (welding start command, welding end command), but the work identification number (work information) is omitted. Only the section information (welding start command, welding end command) may be transmitted to the monitor device PC. Even in this case, if the ID code of the transmission source that is metadata is extracted and arranged in the same time zone, for each identical robot control device, and for each identical welding machine, in order with a time stamp, each of them is a plurality of It can be set as the data of the time order which welded with the arc welding robot.

  In the above-described embodiment, the order of the combination of S102 and S103, the combination of S104 and S105, and the combination of S106 and S107 in the flowchart of FIG. For example, the combination of S102 and S103 may be inserted between the combination of S104 and S105. Further, the combination of S102 and S103 may be arranged after the combination of S104 and S105. Further, a combination of S106 and S107, a combination of S102 and S103, and S104 and S105 may be arranged in this order.

  -Although the said networks 20, 20A, 20B were comprised by the wire, you may comprise by a wireless network.

RC1-RCN ... robot control device, Y1-YN ... welding machine, PC ... monitor device,
10 ... arc welding robot system,
14 ... Network communication unit (transmission unit), 15 ... Storage device (storage unit),
16 ... main control unit, 17 ... network communication unit (communication unit),
20 ... Network, 21 ... CPU (control unit), 23 ... RAM (storage unit),
24. Network communication part (welding machine transmission part),
34. Storage device (monitor storage unit).

Claims (4)

A monitoring device, a plurality of robot control devices that respectively control a plurality of arc welding robots, and a control target that is provided for each of the robot control devices according to command information related to welding from the robot control device during a welding operation process In an arc welding robot system in which a plurality of welding machines for supplying a welding current to a welding torch of an arc welding robot are connected via a common network,
Each robot control device, at the start and end of the welding operation process, transmits process section information related to the welding operation process to the monitor device, and each time the execution state changes during the welding operation process, A transmission unit for transmitting the execution state information (hereinafter referred to as execution state information) to a welding machine to be controlled;
Each welding machine is
A storage unit for storing the monitor value acquired during the welding operation process, the command information, and the execution state information (hereinafter referred to as acquisition information) in time series;
A welding machine transmitter that transmits the acquired information stored in the storage unit to the monitor device;
The said monitoring apparatus is an arc welding robot system provided with the monitor memory | storage part which attaches a time stamp and preserve | saves the process division information transmitted from each said robot control apparatus, and the said acquisition information transmitted from each said welding machine.   The transmission unit of each robot control device transmits an ID code of a transmission source to the monitor device at the time of transmission of the process section information, and each welding machine uses the ID code of the transmission source as the acquisition information. The arc welding robot system according to claim 1, which is given and transmitted to the monitor device.   The welding machine transmission unit performs communication by reducing the amount of data transmitted per unit time during the welding operation step, and increases the amount of data transmitted per unit time after the welding operation step. The arc welding robot system according to claim 1 or 2. The welding machine includes a control unit that controls a welding power source that supplies the welding current and controls the welding machine transmission unit.
The welding machine transmission unit performs communication by background processing by the control unit during the welding operation process and performs communication by foreground processing by the control unit after the welding operation process, and the control unit performs the foreground processing. 3. The arc welding robot system according to claim 1, wherein the welding machine transmitter is configured to perform communication by setting the load of the welding machine to be larger than the load in the background processing.