Welding system and method for installing a welding system

Abstract

A welding system and an installation method thereof are provided that allow a welding robot and its control device to be installed at a distance from each other. [Solution] The welding system includes a welding robot, a controller that generates a control signal for the welding robot, a relay device connected to the welding robot and the controller and relaying information between the welding robot and the controller, a welding power source that supplies welding power for welding to the welding robot, a wire feeder connected to the welding power source and supplying welding power to the welding robot, a power supply cable, and a control cable. One end of the power supply cable is connected to the portable wire feeder and supplies welding power from a stationary welding power source to the portable wire feeder, and a control signal for the portable welding robot is transmitted from the stationary control device to the portable relay device. One end of the control cable is connected to the portable relay device and the other end is connected to the portable welding robot and transmits a control signal for the portable welding robot that is relayed by the portable relay device.

Description

Technical Field

[0001] The present invention relates to a welding system and a method for installing the welding system.

Background Art

[0002] In steel structures, bridges, shipbuilding, etc., welding robots may be used for welding work. Some welding robots can run on rails, perform sensing automatically, and calculate welding conditions automatically.

[0003] Regarding welding systems, there is a known technique that can reduce the setup time and reduce the maintenance and repair costs (see, for example, Patent Document 1). This technique includes a welding work management device, a sensor unit, and a wireless terminal for welders. The welding work management device processes and manages data. The sensor unit is connected to the welding work management device and measures the current and voltage of the welding power. The wireless terminal for welders is connected to the welding work management device via a wireless network, and welding data is input. The welding work management device or the wireless terminal for welders calculates a first welding condition including welding current, welding voltage, and arc time based on the measured current and voltage, and calculates temperature and heat input as welding results based on the first welding condition and a second welding condition including welding length and inter-pass temperature input to the wireless terminal for welders, and determines the pass / fail of welding based on the welding results.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] On the other hand, the drive shafts of conventional welding robots are composed of stepping motors. Since a stepping motor monitors its own rotation steps for rotation control, an external sensor such as an encoder is not required. On the other hand, it is difficult for a stepping motor to precisely control the position realized by an encoder and a servo motor. In order to minimize the disturbance caused by the influence of noise, in a general production factory, means such as shortening the length of the cable for transmitting the encoder signal as much as possible are adopted. However, generally, a welding system is composed of a control device, a welding power source, and a welding robot. If an attempt is made to shorten the cable for transmitting the encoder signal, the control cable between the welding power source that controls the welding voltage and current and the control device has to be extended. However, since the welding power source is heavy, there is a high demand to install the welding machine itself on the ground surface at a special construction site.

[0006] An object of the present invention is to provide a welding system and a method for installing the welding system that can be installed with a distance between a welding robot and a control device for controlling the welding robot.

Means for Solving the Problems

[0007] (1) The welding system according to one aspect of the present invention includes a welding robot, a control device that creates a control signal for controlling the welding robot, a relay device that is connected to the welding robot and the control device and relays information between the welding robot and the control device, a welding power source that supplies welding power for welding to the welding robot, a wire feeder that is connected to the welding power source and supplies the welding power to the welding robot, a power supply cable, and a control cable. The welding robot is a portable welding robot for welding steel pipes. The wire feeder is a portable wire feeder separate from the portable welding robot. The welding power source is a stationary welding power source separate from the portable welding robot and the portable wire feeder. The control device is a stationary control device separate from the portable welding robot and the portable wire feeder. The relay device is a portable relay device separate from the portable welding robot, the stationary welding power source, and the stationary control device. One end of the power supply cable is connected to the portable wire feeder and supplies the welding power from the stationary welding power source to the portable wire feeder. The portable relay device transmits a control signal for controlling the portable welding robot from the stationary control device. One end of the control cable is connected to the portable relay device, the other end is connected to the portable welding robot, and transmits a control signal for controlling the portable welding robot and relayed by the portable relay device. This is a welding system characterized by the above.

[0008] (2) The welding system according to one aspect of the present invention is the welding system according to (1) above, further including a welding torch provided on the portable welding robot and a voltage cable for transmitting an arc voltage signal related to the arc voltage of the welding torch. The voltage cable is connected to the portable relay device. The portable relay device transmits the arc voltage signal to the stationary control device. The stationary control device calculates the voltage drop of the arc voltage based on the arc voltage signal from the portable relay device and controls the stationary welding power source to compensate for the calculated voltage drop.

[0009] (3) The welding system according to one aspect of the present invention is the welding system described in (1) or (2) above, further comprising a first power cable for supplying power to the portable welding robot, wherein one end of the first power cable is connected to the portable relay device and the other end is connected to the portable welding robot.

[0010] (4) The welding system according to one aspect of the present invention is the welding system described in any one of (1) to (3) above, further comprising an imaging unit provided on the portable welding robot and a camera cable for supplying power to the imaging unit, wherein one end of the camera cable is connected to the portable relay device and the other end is connected to the portable welding robot.

[0011] (5) The welding system according to one aspect of the present invention is the welding system described in any one of (1) to (4) above, further comprising a second power cable for supplying power to a motor included in the portable wire feeder, wherein one end of the second power cable is connected to the portable relay device and the other end is connected to the portable wire feeder.

[0012] (6) The welding system according to one aspect of the present invention is the welding system described in any one of (1) to (5) above, further comprising a servo motor provided on the portable welding robot and an encoder cable for transmitting an encoder signal of the servo motor, wherein one end of the encoder cable is connected to the portable relay device and the other end is connected to the portable welding robot.

[0013] (7) The welding system according to one aspect of the present invention is the welding system according to any one of (1) to (6) above, wherein the portable welding robot welds a plurality of steel pipes on the same floor of a building, the stationary control device is installed in the building, the portable welding robot is arranged on one of the plurality of steel pipes, and the portable relay device is arranged in any one of the vicinity of one of the plurality of steel pipes, between the plurality of steel pipes, and substantially at the center of the floor where the plurality of steel pipes are located.

[0014] (8) The method for installing a welding system according to one aspect of the present invention is the method for installing a welding system according to any one of (1) to (7) above, wherein the portable welding robot welds a plurality of steel pipes on the same floor of a building, and includes an installation step of installing the stationary control device in the building, a discrimination step of discriminating which one of the portable relay device and the portable welding robot each device of the welding system is, for the device discriminated as the portable relay device in the discrimination step, arranging it in any one of the vicinity of one of the plurality of steel pipes, between the plurality of steel pipes, and substantially at the center of the floor where the plurality of steel pipes are located, and for the device discriminated as the portable welding robot in the discrimination step, an arrangement step of arranging it on one of the plurality of steel pipes.

[0015] (9) The installation method of a welding system according to an aspect of the present invention includes a stationary control device that transmits a digital signal, a portable relay device separate from the stationary control device, the portable relay device being configured to convert the digital signal transmitted from the stationary control device into an analog signal, and a portable welding robot separate from the stationary control device and the portable relay device, the portable welding robot being driven in response to the analog signal converted by the portable relay device and configured to weld a plurality of steel pipes located on the same floor of a building. The installation method of the welding system includes: an installation step of installing the stationary control device in the building; a discrimination step of discriminating whether the device is the portable relay device or the portable welding robot for each of the devices of the welding system; for the device discriminated as the portable relay device in the discrimination step, an arrangement step of arranging the device at any one of a vicinity of one of the plurality of steel pipes, between the plurality of steel pipes, and a substantially center of the floor where the plurality of steel pipes are located; and for the device discriminated as the portable welding robot in the discrimination step, an arrangement step of arranging the device on one of the plurality of steel pipes.

Advantages of the Invention

[0016] According to an embodiment of the present invention, it is possible to provide a welding system and an installation method of the welding system that can be installed with a distance between a welding robot and a control device that controls the welding robot.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0018] Next, the welding system, relay device, welding method, relay method, and installation method of the welding system according to this embodiment will be described with reference to the drawings. The embodiments described below are merely examples, and the embodiments to which the present invention is applied are not limited to the following embodiments. In all the drawings for explaining the embodiments, those having the same function are denoted by the same reference numerals, and repeated explanations are omitted. In addition, “based on XX” as used in this application means “based on at least XX”, and includes cases where it is based on another element in addition to XX. Also, “based on XX” is not limited to the case where XX is directly used, and includes cases where it is based on something obtained by performing calculations or processing on XX. “XX” is an arbitrary element (for example, arbitrary information).

[0019] (Embodiment) (Welding System) FIG. 1 is a diagram showing a welding system according to an embodiment of the present invention. The welding system 1 according to this embodiment is used, for example, to add a steel pipe. When adding a steel pipe SP, the welding robot 100 circulates around the steel pipe SP along the guide rail GL, and the steel pipes are welded together. In FIG. 1, the steel pipe SPa and the steel pipe SPb are added. The welding system 1 includes a welding robot 100, a wire feeder 200, a welding power source 300, a control device 400, and a relay device 500. An example of the welding robot 100 is portable and welds the steel pipe SP. The welding robot 100 includes one or more motors. An example of the one or more motors is a servo motor. By driving each of the one or more motors, the welding robot 100 moves by sliding on the guide rail GL.

[0020] An example of the wire feeder 200 is portable and is configured separately from the welding robot 100. An example of the wire feeder 200 is installed on the floor (floor surface) and used. Also, the wire feeder 200 may be suspended by a suspension member from the beam BE and used. Hereinafter, as an example, the case where the wire feeder 200 is installed on the floor (floor surface) and used will be continued to be described. An example of the welding power source 300 is a stationary type and is configured separately from the welding robot 100 and the wire feeder 200. An example of the control device 400 is a stationary type, and the welding robot 100, the wire feeder 200, and the welding power source 300 are configured separately. An example of the relay device 500 is portable and is configured separately from the welding robot 100, the wire feeder 200, the welding power source 300, and the control device 400. An example of the relay device 500 is installed on the floor (floor surface) and used. Also, the wire feeder 200 may be suspended by a suspension member from the beam BE and used. Hereinafter, as an example, the case where the relay device 500 is installed on the floor (floor surface) and used will be continued to be described.

[0021] In an example of the welding system 1, the welding robot 100, the wire feeder 200, and the relay device 500 may be installed at a position separated from the welding power source 300 and the control device 400. Specifically, the distance from the position of the object to be welded by the welding robot 100 may be 100 m or more. For example, in an example of the welding system 1, the welding robot 100, the wire feeder 200, and the relay device 500 may be installed on a different floor from the welding power source 300 and the control device 400. Specifically, the welding robot 100, the wire feeder 200, and the relay device 500 may be installed on the floor where the welding operation is performed, and the welding power source 300 and the control device 400 may be installed on a floor lower than the floor where the welding operation is performed. By configuring in this way, the welding operation can be performed without installing the very heavy welding power source 300 on a high floor.

[0022] The welding system 1 has a power supply cable PSC. One end of the power supply cable PSC is connected to the welding power source 300, and the other end is connected to the wire feeder 200. An example of the length of the power supply cable PSC is from 50 m to 150 m. The power supply cable PSC supplies the welding power from the welding power source 300 to the wire feeder 200. The welding system 1 has a first control cable CC01. The first control cable CC01 includes a cable with one end connected to the control device 400 and the other end connected to the relay device 500. An example of the length of the cable with one end connected to the control device 400 and the other end connected to the relay device 500 is 50 m or more. The cable with one end connected to the control device 400 and the other end connected to the relay device 500 transmits a control signal for controlling the welding robot 100 output by the control device 400 to the relay device 500. The first control cable CC01 includes a cable (not shown) for supplying power to the devices included in the relay device 500, a cable (not shown) for supplying power to the motor provided in the welding robot 100, and a cable (not shown) for supplying power to the motor provided in the wire feeder 200. The welding system 1 has a second control cable CC02. The second control cable CC02 includes a cable with one end connected to the relay device 500 and the other end connected to the welding robot 100. An example of the length of the cable with one end connected to the relay device 500 and the other end connected to the welding robot 100 is from 15 m to 25 m. The cable with one end connected to the relay device 500 and the other end connected to the welding robot 100 transmits a control signal for controlling the welding robot 100 output by the relay device 500 to the welding robot 100. The second control cable CC02 includes a cable (not shown) for supplying power to the motor provided in the welding robot 100.

[0023] The process of welding by the welding robot 100 will be described. The welding robot 100 welds steel pipes together. The wire feeder 200 measures the welding voltage. For example, the wire feeder 200 measures the arc voltage Varc that drops due to arc discharge. However, the welding robot 100 may also be configured to measure the welding voltage. For example, the welding robot 100 may be configured to measure the arc voltage Varc that drops due to arc discharge. Hereinafter, the case where the wire feeder 200 measures the arc voltage Varc will be described continuously. The wire feeder 200 outputs the measured value of the arc voltage (hereinafter referred to as "welding voltage value") to the relay device 500. Here, the welding voltage value output by the wire feeder 200 to the relay device 500 is an analog value. The relay device 500 acquires the welding voltage value output by the wire feeder 200. The relay device 500 converts the acquired welding power value into a digital value. The relay device 500 transmits the welding voltage value converted into a digital value to the control device 400.

[0024] The control device 400 receives the welding voltage value transmitted by the relay device 500. The control device 400 calculates a command voltage Vset for instructing the welding power source 300 to supply a voltage to the welding robot 100 based on the received welding voltage value. The control device 400 creates command voltage information including information specifying the command voltage Vset obtained by the calculation. The control device 400 outputs the created command voltage information to the welding power source 300. The welding power source 300 acquires (receives the command) the command voltage information output by the control device 400. The welding power source 300 outputs a voltage to the welding robot 100 based on the information specifying the command voltage Vset included in the received command voltage information. The welding robot 100 performs arc discharge with the voltage output by the welding power source 300.

[0025] The process of moving the welding robot 100 will be described. The welding robot 100 acquires the encoder value of each of one or more motors from an encoder (not shown). The encoder value is the result of detecting the rotation value of each of one or more motors in pulses. The welding robot 100 outputs the acquired encoder value of each of one or more motors to the relay device 500. The relay device 500 acquires the encoder value of each of one or more motors output by the welding robot 100. The relay device 500 performs communication conversion on the acquired encoder value of each of one or more motors. The relay device 500 creates a motor rotation value request including the result of performing communication conversion on the encoder value of each of one or more motors. The relay device 500 transmits the created motor rotation value request to the control device 400.

[0026] The control device 400 receives the motor rotation value request transmitted by the relay device 500. The control device 400 acquires the result of performing communication conversion on the encoder value of each of one or more motors included in the received motor rotation value request. Based on the result of performing communication conversion on the encoder value of each of one or more motors thus acquired, the control device 400 calculates the rotation value of each of one or more motors provided in the welding robot 100. The control device 400 creates a motor rotation value response including information specifying the rotation value of each of one or more motors obtained by the calculation. The control device 400 outputs the created motor rotation value response to the relay device 500. The relay device 500 acquires the motor rotation value response output by the welding robot 100. The relay device 500 acquires information specifying the rotation value of each of one or more motors included in the acquired motor rotation value response. The relay device 500 outputs the information specifying the rotation value of each of one or more motors thus acquired to the welding robot 100. Based on the information specifying the rotation value of each of one or more motors output by the relay device 500, the welding robot 100 rotates each of one or more motors.

[0027] Hereinafter, the welding robot 100, the wire feeder 200, the welding power source 300, the control device 400, and the relay device 500 will be sequentially described. (Welding Robot 100) The welding robot 100 welds members such as a plurality of steel materials to be welded (hereinafter also referred to as "welded members"). The welding robot 100 welds the ends of the welded members. An example of the steel material is a steel pipe SP. FIG. 2 is a block diagram showing an example of a welding robot of the welding system according to the present embodiment. The welding robot 100 includes a welding torch 102, an input / output unit 104, a control unit 108, an imaging unit 110, and motors 112-1 to 112-n (n is an integer greater than 0).

[0028] The welding torch 102 welds the welded members together. An example of the welding method is arc welding. Arc welding is a welding method that uses a discharge phenomenon (arc discharge) in air (gas) to join the same metals together. In arc discharge, an arc discharge is generated from the tip of the welding torch 102 toward the groove of the welded member by applying the voltage output by the welding power source 300 to the welding torch 102. When the arc discharge is generated from the tip of the welding torch 102 toward the groove of the welded member, the welded members are welded together. The groove is a space formed between the ends of the welded members. The groove can be obtained, for example, by cutting the end of one of the welded members to form an inclination. The welding robot 100 is installed so that the tip of the welding torch 102 aligns with the groove of the welded member.

[0029] The input / output unit 104 is an interface with the relay device 500. The input / output unit 104 acquires the welding voltage value output by the wire feeder 200. The welding voltage value acquired by the input / output unit 104 is output to the relay device 500. Also, the input / output unit 104 acquires the encoder value output by the control unit 108. The encoder value acquired by the input / output unit 104 is output to the relay device 500. Further, information for specifying the motor rotation value output by the relay device 500 is input to the input / output unit 104. The motor rotation value input to the input / output unit 104 is output to the control unit 108. Also, information for specifying the temperature of the steel material output by a thermometer (not shown) is input to the input / output unit 104. The information for specifying the temperature of the steel material input to the input / output unit 104 is output to the control unit 108.

[0030] The control unit 108 controls the movement of the welding robot 100. The control unit 108 acquires the encoder value of each of one or more motors, and outputs the acquired encoder value of each of the one or more motors to the input / output unit 104. The control unit 108 acquires control signals such as information for specifying the motor rotation value of each of one or more motors from the input / output unit 104, and controls the movement of the welding robot 100 based on the acquired control signals. Specifically, the control unit 108 executes control to move the welding robot 100 by driving each of the motors 112-1 to 112-n based on the information for specifying the motor rotation value of each of the acquired one or more motors. The imaging unit 110 captures the state of welding by the welding robot 100. An example of the imaging unit 110 is a camera. The imaging unit 110 may be, for example, built into the welding robot 100 or may be attached thereto. The imaging unit 110 and the relay device 500 are connected by a cable SC via the wire feeder 200. Also, the imaging unit 110 and the relay device 500 may be connected by a cable CC02 without passing through the wire feeder 200. The cable SC supplies power from the relay device 500 to the motor included in the wire feeder 200. The imaging unit 110 outputs data of an image or video (hereinafter referred to as "image data") acquired by imaging to the relay device 500.

[0031] Each of the motors 112-1 to 112-n is driven by being controlled by the control unit 108. By each of the motors 112-1 to 112-n being driven, the welding robot 100 moves by sliding on the guide rail GL. Returning to FIG. 1, the description will be continued. The guide rail GL assists the movement of the welding robot 100 by supporting the welding robot 100. The guide rail GL is arranged along the welded member so as to surround the welded member in an annular shape in the circumferential direction of the welded member.

[0032] (Wire feeder 200) The wire feeder 200 feeds a welding wire for use in welding. An example of the welding wire is a long solid wire in a coil shape or a flux-cored wire. For example, the wire feeder 200 arranges a pressure roller and a feeding roller attached to the motor shaft vertically, presses the wire from above and below with these two rollers, and feeds the welding wire using the frictional force obtained by the pressing. The welding wire is guided by the conduit cable CC and fed to the welding torch 102. An example of the conduit cable CC has a configuration in which an insulating cylindrical body (insulating cylinder) is coated on a cylindrical conductor. A coil liner is inserted inside the conductor, and the welding wire is guided by this coil liner. Also, the wire feeder 200 measures the welding voltage. Specifically, the wire feeder 200 measures the arc voltage Varc that drops during arc discharge. The wire feeder 200 outputs the welding voltage value, which is the measurement result of the welding voltage, to the relay device 500.

[0033] (Relay device 500) The relay device 500 is realized by a device such as a personal computer, a PLC (Programmable Logic Controller), a server, a smartphone, a tablet computer, or an industrial computer. The relay device 500 includes, for example, an input / output unit 502, an A / D conversion unit 504, a communication conversion unit 506, a processing unit 508, and a communication unit 510. The communication unit 510 is realized by a communication module. The communication unit 510 communicates with other devices such as the control device 400. The communication unit 510 is connected to the control device 400 by, for example, a cable. Also, the communication unit 510 may communicate by a communication method such as a wired LAN. The input / output unit 502 is an interface between the welding robot 100 and the wire feeder 200. The input / output unit 502 is connected to the input / output unit 104 of the welding robot 100 and the wire feeder 200 by, for example, a cable. The input / output unit 502 acquires the welding voltage value output by the wire feeder 200. The A / D conversion unit 504 acquires the welding voltage value from the input / output unit 502. The A / D conversion unit 504 converts the acquired welding voltage value into digital data. The processing unit 508 acquires the result of converting the welding voltage value from the A / D conversion unit 504 into digital data. The processing unit 508 creates a digital welding voltage value including the result of converting the acquired welding voltage value into digital data. The processing unit 508 outputs the created digital welding voltage value to the communication unit 510. The communication unit 510 transmits the digital welding voltage value output by the processing unit 508 to the control device 400.

[0034] The input / output unit 502 acquires the encoder value of each of one or more motors output by the welding robot 100. The communication conversion unit 506 acquires the encoder value of each of one or more motors from the input / output unit 502. The communication conversion unit 506 performs communication conversion by converting the interface in order to transmit the acquired encoder value of each of one or more motors to the control device 400. By converting the interface, different serial communications can be connected. The processing unit 508 acquires the encoder value of each of one or more motors with the interface converted from the communication conversion unit 506. The processing unit 508 creates a motor rotation value request including the acquired encoder value of each of one or more motors with the interface converted. The processing unit 508 outputs the created motor rotation value request to the communication unit 510. The communication unit 510 transmits the motor rotation value request output by the processing unit 508 to the control device 400. The communication unit 510 receives the motor rotation value response transmitted by the control device 400 in response to the motor rotation value request. The processing unit 508 acquires the motor rotation value response from the communication unit 510. The processing unit 508 acquires information for specifying the motor rotation value of each of the one or more motors included in the acquired motor rotation value response. The processing unit 508 outputs the information for specifying the motor rotation value of each of the acquired one or more motors to the input / output unit 502. The input / output unit 502 acquires information for specifying the motor rotation value of each of the one or more motors output by the processing unit 508, and transmits the information for specifying the motor rotation value of each of the acquired one or more motors to the welding robot 100. The communication unit 510 receives the image data transmitted by the welding robot 100. The processing unit 508 acquires the image data received by the communication unit 510. The processing unit 508 may cause a display unit (not shown) to display the state of welding by the welding robot 100 by processing the acquired image data. By configuring in this way, the welding state can be confirmed.

[0035] All or part of the A / D conversion unit 504, the communication conversion unit 506, and the processing unit 508 are, for example, functional units (hereinafter referred to as software functional units) realized by a processor such as a CPU (Central Processing Unit) executing a program stored in a storage unit (not shown). Note that all or part of the A / D conversion unit 504, the communication conversion unit 506, and the processing unit 508 may be realized by hardware such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate Array), or may be realized by a combination of a software functional unit and hardware.

[0036] (Control Device 400) The control device 400 is realized by a device including an industrial computer or the like. The control device 400 includes, for example, a communication unit 402, a calculation unit 404, and a processing unit 406. The communication unit 402 is realized by a communication module. The communication unit 402 communicates with other devices such as a relay device 500 and a welding power source 300. The communication unit 402 is connected to the relay device 500 by a cable, for example. Also, the communication unit 402 may communicate by a communication method such as a wired LAN. Specifically, the communication unit 402 receives the digital welding voltage value transmitted by the relay device 500. The calculation unit 404 acquires information for specifying the digital welding voltage value received by the communication unit 402. The calculation unit 404 calculates a command voltage based on the acquired information for specifying the digital welding voltage value.

[0037] FIG. 3 and FIG. 4 are diagrams for explaining an example of the operation of the welding system according to the present embodiment. With reference to FIGS. 3 and 4, an example of the processing of the calculation unit 404 of the control device 400 will be described. By the control device 400 outputting information for specifying the command voltage Vset to the welding power source 300, the voltage (output voltage Vout) output by the welding power source 300 is uniquely determined by the output characteristics of the welding power source 300. FIG. 4 shows an example of the output characteristics of the welding power source 300. In FIG. 4, the horizontal axis is the output voltage Vout of the welding power source 300, and the vertical axis is the command voltage Vset to the welding power source 300. According to FIG. 4, it can be seen that it is represented by Vset = A × Vout + B (A and B are constants). That is, the command voltage Vset to the welding power source 300 can be expressed by a linear expression of the output voltage Vout of the welding power source 300. Returning to FIG. 3, the description will continue.

[0038] The loads on the voltage (output voltage Vout) output by the welding power source 300 are mainly two: the voltage drop Vdown due to the power cable (power supply cable PSC) and the arc power Varc that drops due to arc discharge. In order to derive the appropriate output voltage Vout, the voltages required by two load elements, namely the voltage drop Vdown due to the power supply cable PSC and the arc power Varc that drops due to arc discharge, are estimated. Based on the result of estimating the required voltage, the command voltage Vset to the welding power source 300 is determined. Information specifying the determined command voltage Vset is input to the welding power source 300. This will be specifically described below. The calculation unit 404 derives a provisional output voltage Vaout based on Equation (1). Vaarc + Vadown + ΔV = Vaout (1) In Equation (1), Vaarc is the set voltage during welding operation and corresponds to the arc voltage Varc that drops due to arc discharge. Since the arc voltage Varc that drops due to arc discharge is a value measured by the welding system 1, in the welding voltage feedback system, the correction term ΔV by feedback control is adjusted in the calculation unit 404 so that the arc voltage Varc that drops due to this arc discharge becomes equal to the provisional set voltage Vaarc during welding operation. Vddown is the theoretical voltage drop due to the power supply cable and is estimated based on the thickness and length of the power supply cable.

[0039] The calculation unit 404 obtains the command voltage Vset corresponding to the derived provisional output voltage Vaout from the output characteristics of the welding power source 300. Specifically, in FIG. 4, as shown in (1), the command voltage Vset is obtained from the provisional output voltage Vaout (in FIG. 4, the output voltage Vout of the welding power source). Returning to FIG. 1, the description will continue. The processing unit 406 obtains information specifying the command voltage Vset from the calculation unit 404. The processing unit 406 creates command voltage information including the information specifying the obtained command voltage Vset. The processing unit 406 outputs the created command voltage information to the communication unit 402. The communication unit 402 obtains the command calculation information output by the processing unit 406 and transmits the obtained command calculation information to the welding power source 300. The communication unit 402 receives the motor rotation value request transmitted by the relay device 500. The calculation unit 404 acquires the motor rotation value request received by the communication unit 402. The calculation unit 404 acquires the result of performing communication conversion on the encoder value of each of one or more motors included in the acquired motor rotation value request. The calculation unit 404 calculates the motor rotation value of each of the one or more motors based on the result of performing communication conversion on the encoder value of each of the acquired one or more motors. The processing unit 406 acquires information for specifying the motor rotation value of each of one or more motors from the calculation unit 404. The processing unit 406 outputs the information for specifying the motor rotation value of each of the acquired one or more motors to the input / output unit 502 of the relay device 500. The input / output unit 502 acquires the information for specifying the motor rotation value of each of one or more motors output by the processing unit 406, and transmits the information for specifying the motor rotation value of each of the acquired one or more motors to the welding robot 100. The calculation unit 404 and the processing unit 406 are functional units (hereinafter referred to as software functional units) realized by a processor such as a CPU executing a program stored in a storage unit (not shown). Note that the calculation unit 404 may be realized by hardware such as an LSI or an FPGA, or may be realized by a combination of a software functional unit and hardware.

[0040] (Welding power source 300) The welding power source 300 includes a command receiving unit 302. The command receiving unit 302 is realized by a communication module. The command receiving unit 302 communicates with other devices such as the control device 400. The command receiving unit 302 is connected to the control device 400 by, for example, a cable. Also, the command receiving unit 302 may communicate by a communication method such as a wired LAN. Specifically, the command receiving unit 302 receives information specifying the command voltage Vset transmitted by the control device 400. The welding power source 300 determines the voltage (output voltage Vout) output by the welding power source 300 from the output characteristics of the welding power source 300 based on the information specifying the command voltage Vset received by the command receiving unit 302. The welding power source 300 supplies power to the welding robot 100 by supplying the determined output voltage Vout to the voltage supply cable PSC. The length of the power supply cable PSC is adjusted by the wire feeder 200 based on the distance between the welding robot 100 and the wire feeder 200. The welding robot 100 performs welding with the power supplied by the welding power source 300.

[0041] (Operation of the welding system 1) FIG. 5 is a flowchart showing Example 1 of the operation of the welding system according to the present embodiment. With reference to FIG. 5, the process of controlling the output voltage Vout supplied to the welding robot 100 will be described. (Step S1-1) The wire feeder 200 measures the welding voltage. (Step S2-1) The wire feeder 200 acquires the welding voltage value and outputs the acquired welding voltage value to the relay device 500. (Step S3-1) In the relay device 500, the input / output unit 502 acquires the welding voltage value output by the wire feeder 200. (Step S4-1) In the relay device 500, the A / D conversion unit 504 acquires the welding voltage value from the input / output unit 502. The A / D conversion unit 504 converts the acquired welding voltage value into digital data.

[0042] (Step S5-1) In the relay device 500, the processing unit 508 acquires the result of converting the welding voltage value from the A / D conversion unit 504 into digital data. The processing unit 508 creates a digital welding voltage value including the result of converting the acquired welding voltage value into digital data. (Step S6-1) In the relay device 500, the processing unit 508 outputs the created digital welding voltage value to the communication unit 510. The communication unit 510 transmits the digital welding voltage value output by the processing unit 508 to the control device 400. (Step S7-1) In the control device 400, the communication unit 402 receives the digital welding voltage value transmitted by the relay device 500. (Step S8-1) In the control device 400, the arithmetic unit 404 derives a provisional output voltage Vaout based on Equation (1). Since the arc voltage Varc that drops during arc discharge is a value measured by the welding system 1, in the welding voltage feedback system, the arithmetic unit 404 adjusts the correction term ΔV by feedback control so that the arc voltage Varc that drops during this arc discharge becomes equal to the provisional set voltage Vaarc during welding operation. An example of this feedback control is PID control (Proportional-Integral-Differential Controller). The arithmetic unit 404 acquires information specifying the digital welding voltage value received by the communication unit 402. The arithmetic unit 404 calculates a command voltage Vset based on the information specifying the acquired digital welding voltage value.

[0043] (Step S9-1) In the control device 400, the processing unit 406 acquires the command voltage Vset from the arithmetic unit 404. The processing unit 406 outputs information specifying the acquired command voltage Vset to the communication unit 402. The communication unit 402 acquires information specifying the command voltage Vset output by the processing unit 406, and transmits the information specifying the acquired command voltage Vset to the welding power source 300. (Step S10-1) In the welding power source 300, the receiving unit 302 receives information specifying the command voltage Vset transmitted by the control device 400. (Step S11-1) The welding power source 300 supplies the output voltage Vout to the voltage supply cable PSC based on the information specifying the command voltage Vset received by the receiving unit 302. (Step S12-1) In the welding robot 100, the welding torch 102 discharges by the output voltage Vout supplied by the welding power source 300.

[0044] FIG. 6 is a flowchart showing an example 2 of the operation of the welding system according to the present embodiment. With reference to FIG. 6, the process of controlling the movement of the welding robot 100 will be described. (Step S1-2) In the welding robot 100, the control unit 108 acquires the encoder value of each of one or more motors, and outputs the acquired encoder value of each of the one or more motors to the input / output unit 104. (Step S2-2) In the welding robot 100, the input / output unit 104 acquires the encoder value of each of the one or more motors output by the control unit 108, and outputs the acquired encoder value of each of the one or more motors to the relay device 500. (Step S3-2) In the relay device 500, the input / output unit 502 acquires the encoder value of each of the one or more motors output by the welding robot 100. (Step S4-2) In the relay device 500, the communication conversion unit 506 acquires the encoder value of each of the one or more motors from the input / output unit 502. The communication conversion unit 506 performs communication conversion by converting the interface in order to transmit the acquired encoder value of each of the one or more motors to the control device 400.

[0045] (Step S5-2) In the relay device 500, the processing unit 508 acquires the encoder value of each of the one or more motors whose interface has been converted by the communication conversion unit 506. The processing unit 508 creates a motor rotation value request including the acquired encoder value of each of the one or more motors whose interface has been converted. (Step S6-2) In the relay device 500, the processing unit 508 outputs the created motor rotation value request to the communication unit 510. The communication unit 510 transmits the motor rotation value request output by the processing unit 508 to the control device 400. (Step S7-2) In the control device 400, the communication unit 402 receives the motor rotation value request transmitted by the relay device 500. (Step S8-2) In the control device 400, the arithmetic unit 404 acquires the motor rotation value request received by the communication unit 402. The arithmetic unit 404 calculates the motor rotation value based on the encoder values of one or more motors obtained by converting the interface included in the acquired motor rotation value request.

[0046] (Step S9-2) In the control device 400, the processing unit 406 acquires information specifying the motor rotation value of each of one or more motors from the arithmetic unit 404. The processing unit 406 creates a motor rotation value response including the information specifying the motor rotation value of each of the acquired one or more motors. The processing unit 406 outputs the created motor rotation value response to the communication unit 402. The communication unit 402 acquires the motor rotation value response output by the processing unit 406 and transmits the acquired motor rotation value response to the relay device 500. (Step S10-2) In the relay device 500, the communication unit 510 receives the motor rotation value response transmitted by the control device 400. (Step S11-2) In the relay device 500, the processing unit 508 acquires the motor rotation value response from the communication unit 510. The processing unit 508 acquires information specifying the motor rotation value of each of one or more motors included in the acquired motor rotation value response. The processing unit 508 outputs the information specifying the motor rotation value of each of the acquired one or more motors to the input / output unit 502. (Step S12-2) In the welding robot 100, the input / output unit 104 acquires information specifying the motor rotation value of each of one or more motors output by the relay device 500. The control unit 108 acquires information specifying the motor rotation value of each of one or more motors from the input / output unit 104, and controls the operation of the welding robot 100 based on the information specifying the motor rotation value of each of the acquired one or more motors.

[0047] (Usage example of the welding system 1) FIG. 7 is a diagram for explaining a usage example of the welding system according to the present embodiment. FIG. 7 shows a floor plan of a building. In FIG. 7, the directions parallel to the floor are defined as the X-axis and the Y-axis, and the direction perpendicular to the X-axis and the Y-axis is defined as the Z-axis. On the same floor of the building, a steel pipe SP-1, a steel pipe SP-2, a steel pipe SP-3, and a steel pipe SP-4 are arranged. An example of the length L1 in the Y-axis direction between the steel pipe SP-1 and the steel pipe SP-4 (between the steel pipe SP2 and the steel pipe SP-4) is from 10 m to 20 m. An example of the length L1 in the X-axis direction between the steel pipe SP-1 and the steel pipe SP-2 (between the steel pipe SP3 and the steel pipe SP-4) is from 10 m to 20 m.

[0048] In the welding system 1, the welding robot 100 is attached so as to be slidable on a guide rail GL-1 attached to the steel pipe SP-1. The relay device 500 is arranged in a central region of the positions where the steel pipe SP-1, the steel pipe SP-2, the steel pipe SP-3, and the steel pipe SP-4 are arranged in a plane composed of the X-axis and the Y-axis. In other words, the relay device 500 is arranged at the center of the floor. The distance between the relay device 500 and the control device 400 can be arranged to be about 60 m to 100 m apart. For this reason, the control device 400 and the welding power source 300 may be arranged on the same floor as the floor where the welding robot 100 and the relay device 500 are arranged, or may be arranged on different floors. In FIG. 7, a wire feeder 200 (not shown) may be suspended from a beam BE. After the welding to the steel pipe SP-1 is completed, the welding to the steel pipe SP-2 is performed. When preparing for the welding to the steel pipe SP-2, the welding robot 100 is moved from the steel pipe SP-1 to the steel pipe SP-2. Here, along with the movement of the welding robot 100, a wire feeder 200 (not shown) is also moved. Since the relay device 500 is arranged in the central area where the steel pipes SP-1, SP-2, SP-3, and SP-4 are arranged, its movement is unnecessary. By arranging the relay device 500 in the central area of the floor, each of the plurality of steel pipes arranged on the floor can be welded by moving the welding robot 100 without moving the relay device 500.

[0049] In the above-described embodiment, the welding robot 100 may acquire information specifying a temperature such as a temperature distribution acquired by a thermometer (not shown), and output the information specifying the acquired temperature to the relay device 500. Further, the welding robot 100 may acquire either one or both of the image data acquired by the imaging unit 110 by imaging the welding state and the information specifying the temperature acquired by the thermometer, and output either one or both of the acquired image data and the information specifying the temperature to the relay device 500. By configuring in this way, the user of the welding system can confirm the welding state by checking the image of the steel material welded by the welding robot and the temperature of the steel material. In the above-described embodiment, the case where the control device 400 and the relay device 500 are connected by wire has been described, but the example is not limited thereto. For example, the control device 400 and the relay device 500 may be wirelessly connected.

[0050] According to the welding system 1 according to this embodiment, the welding system 1 includes a welding robot 100, a control device 400 that creates a control signal for controlling the welding robot 100, and a relay device 500 that is connected to the welding robot 100 and the control device 400 and relays information between the welding robot 100 and the control device 400. The relay device 500 relays the control signal created by the control device 400 to the welding robot 100. By configuring in this way, since the relay device 500 is installed between the welding robot 100 and the control device 400, the distance between the welding robot 100 and the control device 400 can be increased for installation.

[0051] Furthermore, it further includes a welding power source 300 that supplies welding power for welding to the welding robot 100, and a wire feeder 200 that is connected to the welding power source 300 and supplies the welding power source 300 to the welding robot 100. By configuring in this way, the welding wire can be fed to the welding robot 100 by the wire feeder 200, and thus the welding power can be supplied to the welding robot 100.

[0052] In addition, the welding robot 100 includes a welding torch 102. The welding robot 100 or the wire feeder 200 measures the arc voltage of the welding torch 102. The relay device 500 converts the arc voltage measured by the welding robot 100 or the wire feeder 200 into digital information, and relays the result of converting the arc voltage into digital information to the control device 400. The control device 400 derives the voltage drop of the arc voltage based on the result of converting the arc voltage relayed by the relay device 500 into digital information, and creates command voltage information for instructing the welding power source 300 of the welding voltage based on the derived voltage drop. By configuring in this way, digital information can be transmitted between the relay device and the control device, so the distance between the relay device and the control device can be increased. When measuring the arc voltage Varc, it is ideal for the measurement point to be at the welding torch 102, but it becomes a noise source. By having the wire feeder 200 measure the arc voltage, it is possible to avoid placing the measurement point on the line of the welding robot 100 - relay panel (relay device). Also, even if a dedicated cable for measurement is provided separately, the welding robot 100 will have to move it around, which will interfere with its operation. By having the wire feeder 200 measure the arc voltage, the arc voltage can be measured without interfering with the welding robot 100.

[0053] Also, the welding robot 100 includes one or more motors 112 - 1 to 112 - n. The welding robot 100 acquires information specifying the rotation value of each of the one or more motors 112 - 1 to 112 - n. The relay device 500 performs communication conversion on the information specifying the rotation value of each of the one or more motors 112 - 1 to 112 - n acquired by the welding robot 100. The control device 400 calculates the rotation value of each of the one or more motors 112 - 1 to 112 - n based on the result of the communication conversion of the information specifying the rotation value of each of the one or more motors 112 - 1 to 112 - n. The relay device 500 acquires the calculation result of the rotation value of each of the one or more motors 112 - 1 to 112 - n from the control device 400, and relays the acquired calculation result to the welding robot 100. By configuring in this way, the welding robot can be moved. An example of the motors 112 - 1 to 112 - n is a servo motor. By configuring with a servo motor and an encoder, more precise speed control and position control are possible compared to a welding robot configured with a stepping motor, and the welding quality can be improved. Furthermore, by maintaining the portability of the welding system, which is usually contradictory, an improvement in workability can be ensured at the construction site.

[0054] Further, it further includes an imaging unit 110 that acquires image information of the steel material to be welded by the welding robot 100, and an input / output unit 104 that acquires information for specifying the temperature of the steel material. The relay device 500 acquires either one or both of the image information acquired by the imaging unit 110 and the information for specifying the temperature acquired by the input / output unit. By configuring in this way, the user of the welding system can confirm the welding state by checking the image of the steel material to be welded by the welding robot and the temperature of the steel material.

[0055] According to the relay device 500 according to this embodiment, the relay device 500 relays information between the welding robot 100 and a control device 400 that creates a control signal for controlling the welding robot 100. The relay device 500 includes an A / D conversion unit 504 that converts the arc voltage measured by the welding robot 100 into digital information, a processing unit 508 that creates a digital welding voltage value including the result of converting the arc voltage into digital information, and a communication unit 510 that transmits the digital welding voltage value created by the processing unit 508 to the control device 400. By configuring in this way, the relay device can relay the arc voltage acquired by the measurement of the welding robot to the control device 400.

[0056] Further, it further includes a communication conversion unit 506 that performs communication conversion of information for specifying the rotation value of each of one or more motors 112-1 to 112-n provided in the welding robot 100. The processing unit 508 creates a motor rotation value request including the result of communication conversion of the information for specifying the rotation value of each of one or more motors 112-1 to 112-n by the communication conversion unit 506. The communication unit 510 transmits the motor rotation value request created by the processing unit 508 to the control device 400. The communication unit 510 receives a motor rotation value response transmitted by the control device 400 in response to the motor rotation value request. The processing unit 508 relays to the welding robot 100 information specifying the rotation value of each of one or more motors 112-1 to 112-n included in the motor rotation value response received by the communication unit 510. By configuring in this way, the relay device relays to the control device information specifying the rotation value of each of one or more motors provided in the welding robot, and can relay to the welding robot information specifying the rotation value of each of the one or more motors transmitted by the relay device.

[0057] According to the welding method executed by the welding system according to the present embodiment, the welding method is executed by a welding system including a welding robot 100, a control device 400 that controls the welding robot 100, and a relay device 500 that relays information between the welding robot 100 and the control device 400. The welding method includes a step of measuring the arc voltage of the welding torch 102, a step of converting the arc voltage into digital information by a relay device 500 disposed near one steel pipe or between a plurality of steel pipes, a step of the relay device 500 relaying the result of converting the arc voltage into digital information to the control device 400, a step of the control device 400 deriving the voltage drop of the arc voltage based on the result of converting the arc voltage into digital information, a step of the control device 400 creating instruction voltage information for instructing the welding voltage to the welding power source based on the derived arc voltage and the voltage drop, and a step of the control device 400 outputting the created instruction voltage information to a welding power source 300 that supplies welding power for welding the welding robot 100. By configuring in this way, since the welding power source can supply the welding voltage to the welding robot based on the instruction voltage information output by the control device, each of one or more steel pipes can be welded.

[0058] Further, the welding robot 100 has steps of obtaining information specifying the rotational values of each of one or more motors 112-1 to 112-n, the relay device 500 has a step of performing communication conversion of the information specifying the rotational values of each of one or more motors 112-1 to 112-n obtained by the welding robot 100, the control device 400 has a step of calculating the rotational values of each of one or more motors 112-1 to 112-n based on the result of the communication conversion of the information specifying the rotational values of each of one or more motors 112-1 to 112-n, the relay device 500 has a step of obtaining the calculation result of the rotational values of each of one or more motors 112-1 to 112-n from the control device 400 and relaying the obtained calculation result to the welding robot 100, and the welding robot 100 has a step of moving based on the calculation result. By configuring in this way, the welding robot 100 can be moved.

[0059] According to the relay method executed by the relay device according to the present embodiment, the relay method is a relay method executed by the relay device 500 that relays information between the welding robot 100 and the control device 400 that creates a control signal for controlling the welding robot 100, and includes a step of converting the arc voltage into digital information, a step of creating a digital welding voltage value including the result of converting the arc voltage into digital information, and a step of transmitting the digital welding voltage value to the control device 400. By configuring in this way, the relay device 500 can relay the arc voltage measured by the welding robot 100 to the control device 400.

[0060] A welding system according to an aspect of the present invention includes a portable welding robot (in an embodiment, welding robot 100) for welding a steel pipe SP, a portable wire feeder (in an embodiment, wire feeder 200) separate from the portable welding robot, a stationary welding power source (in an embodiment, welding power source 300) separate from the portable welding robot and the portable wire feeder, a stationary control device (in an embodiment, control device 400) separate from the portable welding robot, the portable wire feeder, and the stationary welding power source, a portable relay device (in an embodiment, control device 400) separate from the portable welding robot, the portable wire feeder, the stationary welding power source, and the stationary control device, a power supply cable PSC, a first control cable CC01, and a second control cable CC02. One end of the power supply cable PSC is connected to the stationary welding power source, the other end is connected to the portable wire feeder, and the welding power from the stationary welding power supplies the portable wire feeder. One end of the first control cable CC01 is connected to the stationary control device, the other end is connected to the portable relay device, and transmits a control signal for controlling the portable welding robot, which is a control signal from the stationary control device. One end of the second control cable CC02 is connected to the portable relay device, the other end is connected to the portable welding robot, and transmits a control signal for controlling the portable welding robot, which is a control signal relayed by the portable relay device. By configuring in this way, since the portable relay device is installed between the portable welding robot and the stationary control device, they can be installed at a distance from each other.

[0061] The welding system further includes a welding torch provided on the portable welding robot and a voltage cable for transmitting an arc voltage signal related to the arc voltage of the welding torch. The voltage cable is connected to the portable relay device, the first control cable transmits the arc voltage signal from the portable relay device to the stationary control device, the stationary control device calculates the voltage drop of the arc voltage based on the arc voltage signal from the portable relay device, and controls the stationary supply device to compensate for the calculated voltage drop. By configuring in this way, the distance between the portable welding robot and the stationary control device can be increased. In addition, the influence of noise caused by the cable for power supply (especially the influence on the encoder signal) can be reduced.

[0062] Furthermore, a power cable for supplying power to the portable welding robot is further provided. One end of the power cable is connected to the portable relay device, and the other end is connected to the portable welding robot. By configuring in this way, the complexity of handling the cable can be reduced. Although the power cable for supplying power to the portable welding robot can also be a noise source, the influence of the noise of these cables is considerably smaller compared to that of the power cable. Therefore, by connecting the power cable to the portable welding robot via the portable relay device, the complexity of handling the cable can be reduced.

[0063] Furthermore, an imaging unit provided in the portable welding robot and a camera cable for supplying power to the imaging unit are further provided. One end of the camera cable is connected to the portable relay device, and the other end is connected to the portable welding robot. By configuring in this way, the complexity of handling the cable can be reduced. Although the camera cable for supplying power to the imaging unit can also be a noise source, the influence of the noise of these cables is considerably smaller compared to that of the power cable. Therefore, by connecting the camera cable to the portable welding robot via the portable relay device, the complexity of handling the cable can be reduced.

[0064] Furthermore, a servo motor provided in the portable welding robot and an encoder cable for transmitting the encoder signal of the servo motor are further provided. One end of the encoder cable is connected to the portable relay device, and the other end is connected to the portable welding robot. By configuring in this way, since the power supply cable for supplying welding power becomes a large noise source, it can be connected to each of the stationary welding power source and the portable wire feeder without passing through the portable relay device, so that the noise generated in the power supply cable can be reduced from affecting the encoder signal.

[0065] A method for installing a welding system according to an aspect of the present invention includes a stationary control device that transmits a digital signal (in the embodiment, the control device 400), a portable relay device separate from the stationary control device (in the embodiment, the relay device 500), which converts the digital signal transmitted from the stationary control device into an analog signal, and a portable welding robot separate from the stationary control device and the portable relay device (in the embodiment, the welding robot 100), which is driven according to the analog signal converted by the portable relay device and welds a plurality of steel pipes SP on the same floor of a building. The method for installing a welding system includes an installation step of installing the stationary control device in a building, a discrimination step of discriminating whether it is a portable relay device or a portable welding robot for one of the devices of the welding system, and an arrangement step of arranging the device discriminated as the portable relay device in the center of the floor where there are a plurality of steel pipes, and arranging the device discriminated as the portable welding robot in one of the plurality of steel pipes. The installation step, the discrimination step, and the arrangement step are executed by, for example, a work robot. By configuring in this way, the portable welding robot can be driven according to the analog signal converted by the portable relay device, and a plurality of steel pipes on the same floor of the building can be welded.

[0066] The embodiments have been described above, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the gist of the invention. These embodiments are included in the scope and gist of the invention, and at the same time, are included in the invention described in the claims and the equivalent scope thereof.

[0067] Note that the above-described welding robot 100, control device 400, and relay device 500 may be implemented by a computer. In that case, a program for realizing the functions of each functional block is recorded on a computer-readable recording medium. The program recorded on this recording medium may be read into a computer system and realized by the CPU executing it. Here, the "computer system" is assumed to include hardware such as an OS (Operating System) and peripheral devices. Also, the "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs. Further, the "computer-readable recording medium" includes storage devices such as hard disks built into the computer system.

[0068] Furthermore, the "computer-readable recording medium" may include those that hold a program dynamically for a short time. Those that hold a program dynamically for a short time are, for example, communication lines when transmitting a program via a network such as the Internet or a communication line such as a telephone line. Also, the "computer-readable recording medium" may include those that hold a program for a certain period of time, such as volatile memories inside computer systems that serve as servers or clients. Also, the above program may be for realizing a part of the aforementioned functions. Also, the above program may be realizable in combination with a program already recorded in the computer system for realizing the aforementioned functions. Also, the above program may be realized using a programmable logic device. The programmable logic device is, for example, an FPGA (Field Programmable Gate Array).

[0069] Note that the above-mentioned welding robot 100, control device 400, and relay device 500 have a computer inside. And the processes of each of the above-mentioned welding robot 100, control device 400, and relay device 500 are stored in a computer-readable recording medium in the form of a program, and the above processes are performed by the computer reading and executing this program. Here, the computer-readable recording medium refers to a magnetic disk, magneto-optical disk, CD-ROM, DVD-ROM, semiconductor memory, etc. Also, this computer program may be distributed to the computer via a communication line, and the computer that has received this distribution may execute the program. Also, the above program may be for realizing a part of the functions described above. Furthermore, it may be a so-called differential file (differential program) that can realize the functions described above in combination with a program already recorded in the computer system.

Explanation of Signs

[0070] 1 Welding system 100 Welding robot 102 Welding torch 104 Input / output unit 108 Control unit 110 Imaging unit 112-1, ···, 112-n Motors 200 Wire feeder 300 Welding power source 302 Command receiving unit 400 Control device 402 Communication unit 404 Arithmetic unit 406 Processing unit 500 Relay device 502 Input / output unit 504 A / D conversion unit 506 Communication conversion unit 508 Processing unit 510 Communication unit

Claims

1. A welding robot, a control device for creating a control signal for controlling the welding robot, a relay device connected to the welding robot and the control device for relaying information between the welding robot and the control device, a welding power source for supplying welding power for welding to the welding robot, a wire feeder connected to the welding power source for supplying the welding power to the welding robot, a power supply cable, a control cable, comprising: the welding robot is a portable welding robot for welding steel pipes, the wire feeder is a portable wire feeder separate from the portable welding robot, the welding power source is a stationary welding power source separate from the portable welding robot and the portable wire feeder, the control device is a stationary control device separate from the portable welding robot and the portable wire feeder, the relay device is a portable relay device separate from the portable welding robot, the stationary welding power source, and the stationary control device, one end of the power supply cable is connected to the portable wire feeder and supplies the welding power from the stationary welding power source to the portable wire feeder, the portable relay device transmits a control signal for controlling the portable welding robot from the stationary control device, one end of the control cable is connected to the portable relay device, the other end is connected to the portable welding robot, and transmits a control signal for controlling the portable welding robot and relayed by the portable relay device, A welding system, characterized in that.

2. a welding torch provided on the portable welding robot, a voltage cable for transmitting an arc voltage signal related to the arc voltage of the welding torch, further comprising: the voltage cable is connected to the portable relay device, the portable relay device transmits the arc voltage signal to the stationary control device, the stationary control device calculates the voltage drop of the arc voltage based on the arc voltage signal from the portable relay device and controls the stationary welding power source to compensate for the calculated voltage drop, The welding system according to claim 1, characterized in that.

3. a first power cable for supplying power to the portable welding robot, further comprising: The first power cable has one end connected to the portable relay device and the other end connected to the portable welding robot. The welding system according to claim 1 or 2, characterized in that.

4. An imaging unit provided in the portable welding robot; A camera cable that supplies power to the imaging unit; Further comprising: One end of the camera cable is connected to the portable relay device and the other end is connected to the portable welding robot. The welding system according to any one of claims 1 to 3, characterized in that.

5. A second power cable that supplies power to a motor included in the portable wire feeder; Further comprising: One end of the second power cable is connected to the portable relay device and the other end is connected to the portable wire feeder. The welding system according to any one of claims 1 to 4, characterized in that.

6. A servo motor provided in the portable welding robot; An encoder cable that transmits an encoder signal of the servo motor; Further comprising: One end of the encoder cable is connected to the portable relay device and the other end is connected to the portable welding robot. The welding system according to any one of claims 1 to 5, characterized in that.

7. The portable welding robot welds a plurality of steel pipes on the same floor of a building. The stationary control device is installed in the building. The portable welding robot is disposed on one of the plurality of steel pipes. The portable relay device is disposed in the vicinity of one of the plurality of steel pipes, between the plurality of steel pipes, or substantially in the center of the floor where the plurality of steel pipes are located. The welding system according to any one of claims 1 to 6, characterized in that.

8. A method for installing the welding system according to any one of claims 1 to 7, The portable welding robot welds a plurality of steel pipes on the same floor of a building. An installation step of installing the stationary control device in the building; A determination step of determining whether it is the portable relay device or the portable welding robot for one of the devices of the welding system. For the device determined to be the portable relay device in the determination step, it is arranged in any one of the vicinity of one of the plurality of steel pipes, between the plurality of steel pipes, and approximately at the center of the floor where the plurality of steel pipes are located. For the device determined to be the portable welding robot in the determination step, there is an arrangement step of arranging it on one of the plurality of steel pipes, A method for installing a welding system comprising the same.

9. A stationary control device that transmits a digital signal, A portable relay device separate from the stationary control device, which converts the digital signal transmitted from the stationary control device into an analog signal, A portable welding robot separate from the stationary control device and the portable relay device, which is driven according to the analog signal converted by the portable relay device and welds a plurality of steel pipes on the same floor of a building. A method for installing a welding system comprising: An installation step of installing the stationary control device in the building, A determination step of determining which of the portable relay device and the portable welding robot is one of the devices of the welding system, For the device determined to be the portable relay device in the determination step, it is arranged in any one of the vicinity of one of the plurality of steel pipes, between the plurality of steel pipes, and approximately at the center of the floor where the plurality of steel pipes are located. For the device determined to be the portable welding robot in the determination step, there is an arrangement step of arranging it on one of the plurality of steel pipes, A method for installing a welding system comprising the same.

Images