Welding system

Abstract

To provide a welding system installable by spacing a welding robot and a control device thereof apart from each other.SOLUTION: A welding system 1 comprises: a welding robot 100; a control device 400 that generates a control signal for controlling the welding robot 100; a connection device 500 separate from the welding robot 100; a welding power source 300; a wire feeder 200 that is connected to the welding power source 300 and that supplies welding power for welding to the welding robot 100; a first cable CC01 connected at one end to the control device 400 and at the other end to the connection device 500; and a second cable CC02 connected at one end to the connection device 500 and at the other end to the welding robot 100.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a welding system. [Background technology]

[0002] Welding robots are sometimes used for welding work in steel frames, bridges, shipbuilding, etc. Some welding robots move on rails, perform fully automatic sensing, and automatically calculate welding conditions.

[0003] BACKGROUND ART With regard to welding systems, there is known a technique that can reduce the time and effort required for setup and can reduce the costs of maintenance and repair (see, for example, Patent Document 1). This technology comprises a welding work management device, a sensor unit, and a wireless terminal for the welder. 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 the welder is connected to the welding work management device via a wireless network and receives welding data. The welding work management device or the wireless terminal for the welder calculates first welding conditions, including the welding current, welding voltage, and arc time, based on the measured current and voltage. Based on the first welding conditions and second welding conditions, including the weld length and interpass temperature, input to the wireless terminal for the welder, the welding results are calculated, including the temperature and heat input. The pass / fail of the welding is determined based on the welding results. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-110782 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, the drive shaft of conventional welding robots is made up of stepping motors. Stepping motors monitor their own rotation steps to control rotation, so external sensors such as encoders are not required. However, it is difficult for stepping motors to achieve the precise position control that can be achieved with encoders and servo motors. In order to minimize disturbances caused by noise, typical production factories employ measures such as shortening the length of the cable that transmits the encoder signal as much as possible. However, a welding system generally consists of a control device, a welding power source, and a welding robot, and if an attempt is made to shorten the cable that transmits the encoder signal, the control cable between the welding power source, which controls the welding voltage and current, and the control device must be extended. However, because welding power sources are heavy, there is a strong demand for the welding machine itself to be installed above ground level at special construction sites.

[0006] An object of the present invention is to provide a welding system in which a welding robot and a control device that controls the welding robot can be installed at a distance from each other. [Means for solving the problem]

[0007] A welding system according to one embodiment of the present invention includes a welding robot, a control device that generates a control signal for controlling the welding robot, a connection device separate from the welding robot, a welding power source, a wire feeder connected to the welding power source and supplying welding power for welding to the welding robot, a first cable having one end connected to the control device and the other end connected to the connection device, and a second cable having one end connected to the connection device and the other end connected to the welding robot. [Effects of the Invention]

[0008] According to an embodiment of the present invention, a welding system can be provided in which a welding robot and a control device that controls the welding robot can be installed at a distance from each other. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a welding system according to an embodiment of the present invention. [Figure 2] 1 is a block diagram showing an example of a welding robot of a welding system according to an embodiment of the present invention; [Figure 3] FIG. 3 is a diagram for explaining an example of the operation of the welding system according to the present embodiment. [Figure 4] FIG. 3 is a diagram for explaining an example of the operation of the welding system according to the present embodiment. [Figure 5] 4 is a flowchart showing a first example of the operation of the welding system according to the present embodiment. FIG. [Figure 6] FIG. 6 is a flowchart showing a second example of the operation of the welding system according to the present embodiment. [Figure 7] 1 is a diagram for explaining an example of use of a welding system according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, a welding system, a relay device, a welding method, a relay method, and a method for installing a welding system according to the present embodiment will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiments to which the present invention is applied are not limited to the following embodiment. In all the drawings for explaining the embodiments, the same reference numerals are used for components having the same functions, and repeated explanations will be omitted. Furthermore, in this application, "based on XX" means "based on at least XX," and includes cases where it is based on other elements in addition to XX. Furthermore, "based on XX" is not limited to cases where XX is used directly, but also includes cases where it is based on XX that has been calculated or processed. "XX" is any element (for example, any information).

[0011] (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 join steel pipes. When joining a steel pipe SP, a welding robot 100 moves around the steel pipe SP along a guide rail GL, thereby welding the steel pipes together. In FIG. 1, a steel pipe SPa and a steel pipe SPb are joined together. 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 a portable robot that welds steel pipes SP. The welding robot 100 is equipped with one or more motors. An example of the one or more motors is a servo motor. When each of the one or more motors is driven, the welding robot 100 slides on a guide rail GL and moves.

[0012] An example of the wire feeder 200 is portable and configured separately from the welding robot 100. An example of the wire feeder 200 is installed on the floor (floor surface) for use. The wire feeder 200 may also be used by being suspended from a beam BE by a suspension member. Below, as an example, the case where the wire feeder 200 is installed on the floor (floor surface) for use will be described. An example of welding power source 300 is a stationary type, in which welding robot 100 and wire feeder 200 are configured separately. An example of control device 400 is a stationary type, in which welding robot 100, wire feeder 200, and welding power source 300 are configured as separate entities. An example of relay device 500 is portable, and welding robot 100, wire feeder 200, welding power source 300, and control device 400 are configured separately. An example of relay device 500 is installed on the floor (floor surface) for use. Wire feeder 200 may also be used by being suspended from beam BE by a suspension member. Below, as an example, a case where relay device 500 is installed on the floor (floor surface) for use will be described.

[0013] In one example of welding system 1, welding robot 100, wire feeder 200, and relay device 500 may be installed at a location separate from welding power source 300 and control device 400. Specifically, the distance between the location of the object to be welded by welding robot 100 may be 100 m or more. For example, in one example of welding system 1, welding robot 100, wire feeder 200, and relay device 500 may be installed on a different floor from welding power source 300 and control device 400. Specifically, welding robot 100, wire feeder 200, and relay device 500 may be installed on the floor where welding work is performed, and welding power source 300 and control device 400 may be installed on a floor below the floor where welding work is performed. With this configuration, welding work can be performed without installing welding power source 300, which is very heavy, on a higher floor.

[0014] Welding system 1 includes a power supply cable PSC. One end of power supply cable PSC is connected to welding power source 300, and the other end is connected to wire feeder 200. The length of power supply cable PSC is, for example, 50 m to 150 m. Power supply cable PSC supplies welding power from welding power source 300 to wire feeder 200. Welding system 1 has a first control cable CC01. First control cable CC01 includes a cable having one end connected to control device 400 and the other end connected to relay device 500. An example of the length of the cable having one end connected to control device 400 and the other end connected to relay device 500 is 50 m or more. The cable having one end connected to control device 400 and the other end connected to relay device 500 transmits a control signal for controlling welding robot 100 output by control device 400 to relay device 500. First control cable CC01 includes a cable (not shown) that supplies power to devices included in relay device 500, a cable (not shown) that supplies power to a motor provided in welding robot 100, and a cable (not shown) that supplies power to a motor provided in wire feeder 200. Welding system 1 has a second control cable CC02. Second control cable CC02 includes a cable having one end connected to relay device 500 and the other end connected to welding robot 100. An example of the length of the cable having one end connected to relay device 500 and the other end connected to welding robot 100 is 15 m to 25 m. The cable having one end connected to relay device 500 and the other end connected to welding robot 100 transmits a control signal output by relay device 500 for controlling welding robot 100 to welding robot 100. Second control cable CC02 includes a cable (not shown) that supplies power to a motor provided in welding robot 100.

[0015] The welding process performed by the welding robot 100 will now 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 measure the welding voltage. For example, the welding robot 100 may measure the arc voltage Varc that drops due to arc discharge. Below, the explanation will continue for the case where the wire feeder 200 measures the arc voltage Varc. Wire feeder 200 outputs a measurement value of the arc voltage (hereinafter referred to as "welding voltage value") to relay device 500. Here, the welding voltage value output by wire feeder 200 to relay device 500 is an analog value. Relay device 500 acquires the welding voltage value output by wire feeder 200. Relay device 500 converts the acquired welding power value into a digital value. Relay device 500 transmits the converted digital welding voltage value to control device 400.

[0016] Control device 400 receives the welding voltage value transmitted by relay device 500. Based on the received welding voltage value, control device 400 calculates a command voltage Vset for instructing welding power source 300 on the voltage to be supplied to welding robot 100. Control device 400 creates command voltage information including information specifying command voltage Vset obtained by the calculation. Control device 400 outputs the created command voltage information to welding power source 300. Welding power source 300 acquires (receives) command voltage information output by control device 400. Welding power source 300 outputs a voltage to welding robot 100 based on information specifying command voltage Vset included in the received command voltage information. The welding robot 100 generates an arc discharge using the voltage output from the welding power source 300 .

[0017] The process of moving the welding robot 100 will be described. The welding robot 100 acquires the encoder values ​​of each of one or more motors from an encoder (not shown). The encoder values ​​are the results of detecting the rotation values ​​of each of one or more motors in pulses. The welding robot 100 outputs the acquired encoder values ​​of each of one or more motors to the relay device 500. The relay device 500 acquires the encoder values ​​of one or more motors output by the welding robot 100. The relay device 500 performs communication conversion of the acquired encoder values ​​of one or more motors. The relay device 500 creates a motor rotation value request including the results of the communication conversion of the encoder values ​​of one or more motors. The relay device 500 transmits the created motor rotation value request to the control device 400.

[0018] The control device 400 receives the motor rotation value request transmitted by the relay device 500. The control device 400 acquires the result of communication conversion of the encoder values ​​of one or more motors included in the received motor rotation value request. The control device 400 calculates the rotation value of each of the one or more motors provided in the welding robot 100 based on the acquired result of communication conversion of the encoder values ​​of each of the one or more motors. The control device 400 creates a motor rotation value response including information identifying the rotation value of each of the 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 the information identifying the rotation value of each of the one or more motors included in the acquired motor rotation value response. The relay device 500 outputs the acquired information identifying the rotation value of each of the one or more motors to the welding robot 100. The welding robot 100 rotates each of the one or more motors based on the information output by the relay device 500 that specifies the rotation value of each of the one or more motors.

[0019] The welding robot 100, the wire feeder 200, the welding power source 300, the control device 400, and the relay device 500 will be described below in order. (Welding Robot 100) The welding robot 100 welds together a plurality of steel materials or other members to be welded (hereinafter also referred to as "members to be welded"). The welding robot 100 welds together the ends of the members to be welded. 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 this embodiment. Welding robot 100 includes welding torch 102, input / output unit 104, control unit 108, imaging unit 110, and motors 112-1 to 112-n (n is an integer greater than 0).

[0020] The welding torch 102 welds the workpieces together. One example of a welding method is arc welding. Arc welding is a welding method that uses an electric discharge phenomenon (arc discharge) in air (gas) to join the same metals together. In the arc discharge, a voltage output from the welding power source 300 is applied to the welding torch 102, causing an arc discharge from the tip of the welding torch 102 toward the groove of the workpieces to be welded. The workpieces are welded together by causing an arc discharge from the tip of the welding torch 102 toward the groove of the workpieces to be welded. The groove is a space formed between the ends of the workpieces to be welded. The groove is obtained, for example, by grinding the end of one of the workpieces to form a bevel. The welding robot 100 is installed so that the tip of the welding torch 102 is aligned with the groove of the workpieces to be welded.

[0021] The input / output unit 104 is an interface with the relay device 500. The input / output unit 104 acquires a 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. The input / output unit 104 also acquires an 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. The input / output unit 104 also receives input of information specifying a motor rotation value output by the relay device 500. The motor rotation value input to the input / output unit 104 is output to the control unit 108. The input / output unit 104 also receives input of information specifying the temperature of the steel material output by a thermometer (not shown). The information specifying the temperature of the steel material input to the input / output unit 104 is output to the control unit 108.

[0022] The control unit 108 controls the movement of the welding robot 100. The control unit 108 acquires the encoder values ​​of each of the one or more motors, and outputs the acquired encoder values ​​of each of the one or more motors to the input / output unit 104. The control unit 108 acquires control signals such as information specifying the motor rotation values ​​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 acquired information specifying the motor rotation values ​​of one or more motors. The imaging unit 110 captures images of welding being performed by the welding robot 100. An example of the imaging unit 110 is a camera. The imaging unit 110 may be built into the welding robot 100 or may be attached to it. The imaging unit 110 and the relay device 500 are connected by a cable SC via the wire feeder 200. Alternatively, the imaging unit 110 and the relay device 500 may be connected by a cable CC02 without the wire feeder 200. The cable SC supplies power from the relay device 500 to a motor provided in the wire feeder 200. The imaging unit 110 outputs image or video data (hereinafter referred to as "image data") acquired by capturing the images to the relay device 500.

[0023] Each of motors 112-1 to 112-n is driven under the control of control unit 108. As each of motors 112-1 to 112-n is driven, welding robot 100 moves by sliding on guide rails GL. Returning to FIG. 1, the description will continue. The guide rail GL supports the welding robot 100, thereby assisting the movement of the welding robot 100. The guide rail GL is arranged along the members to be welded so as to surround the members to be welded in an annular shape in the circumferential direction of the members to be welded.

[0024] (Wire feeder 200) Wire feeder 200 feeds welding wire for use in welding. Examples of welding wire include a long coiled solid wire and a flux-cored wire. For example, wire feeder 200 has a pressure roller and a feed roller attached to a motor shaft arranged above and below, and these two rollers pressurize the wire from above and below, and feed the welding wire by utilizing the frictional force generated by this pressure. The welding wire is guided by a conduit cable CC and fed to welding torch 102. An example of a conduit cable CC has a configuration in which a cylindrical conductor is covered with an insulating cylinder (insulating cylinder). A coil liner is inserted inside the conductor, and the welding wire is guided by this coil liner. Wire feeder 200 also measures the welding voltage. Specifically, wire feeder 200 measures the arc voltage Varc that drops due to arc discharge. Wire feeder 200 outputs the welding voltage value, which is the measurement result of the welding voltage, to relay device 500.

[0025] (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, an industrial computer, etc. 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. The communication unit 510 may also communicate using a communication method such as a wired LAN. Input / output unit 502 is an interface between welding robot 100 and wire feeder 200. Input / output unit 502 is connected to input / output unit 104 of welding robot 100 and wire feeder 200, for example, by a cable. Input / output unit 502 acquires the welding voltage value output by wire feeder 200. A / D conversion unit 504 acquires the welding voltage value from input / output unit 502. A / D conversion unit 504 converts the acquired welding voltage value into digital data. Processing unit 508 acquires the result of converting the welding voltage value into digital data from A / D conversion unit 504. Processing unit 508 creates a digital welding voltage value including the result of converting the acquired welding voltage value into digital data. Processing unit 508 outputs the created digital welding voltage value to communication unit 510. Communication unit 510 transmits the digital welding voltage value output by processing unit 508 to control device 400.

[0026] The input / output unit 502 acquires the encoder values ​​of one or more motors output by the welding robot 100 . The communication conversion unit 506 acquires the encoder values ​​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 values ​​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 values ​​of each of the one or more motors whose interfaces have been converted from the communication conversion unit 506. The processing unit 508 creates a motor rotation value request including the encoder values ​​of each of the one or more motors whose interfaces have been 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 a motor rotation value response transmitted by the control device 400 in response to the motor rotation value request. The processing unit 508 acquires a motor rotation value response from the communication unit 510. The processing unit 508 acquires information 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 acquired information specifying the motor rotation value of each of the one or more motors to the input / output unit 502. The input / output unit 502 acquires information specifying the motor rotation value of each of the one or more motors output by the processing unit 508, and transmits the acquired information specifying the motor rotation value of each of the 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 process the acquired image data to display the state of welding by the welding robot 100 on a display unit (not shown). With this configuration, the welding state can be confirmed.

[0027] All or part of the A / D conversion unit 504, communication conversion unit 506, and processing unit 508 are functional units (hereinafter referred to as software functional units) that are 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, communication conversion unit 506, and 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 software functional units and hardware.

[0028] (Control device 400) The control device 400 is realized by a device including an industrial computer, etc. The control device 400 includes, for example, a communication unit 402, a calculation unit 404, and a processing unit 406. Communication unit 402 is realized by a communication module. Communication unit 402 communicates with other devices such as relay device 500 and welding power source 300. Communication unit 402 is connected to relay device 500 by, for example, a cable. Communication unit 402 may also communicate using a communication method such as a wired LAN. Specifically, communication unit 402 receives the digital welding voltage value transmitted by relay device 500. The calculation unit 404 acquires information 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 specifying the digital welding voltage value.

[0029] 3 and 4 are diagrams for explaining an example of the operation of the welding system according to this embodiment. An example of the processing of the calculation unit 404 of the control device 400 will be described with reference to FIGS. Control device 400 outputs information specifying command voltage Vset to welding power source 300, so that the voltage output by welding power source 300 (output voltage Vout) is uniquely determined by the output characteristics of welding power source 300. Fig. 4 shows an example of the output characteristics of welding power supply 300. In Fig. 4, the horizontal axis represents output voltage Vout of welding power supply 300, and the vertical axis represents command voltage Vset to welding power supply 300. Fig. 4 shows that Vset can be expressed as Vset = A × Vout + B (A and B are constants). In other words, command voltage Vset to welding power supply 300 can be expressed as a linear expression of output voltage Vout of welding power supply 300. Returning to Fig. 3, the explanation will continue.

[0030] The load on the voltage (output voltage Vout) output by welding power supply 300 is mainly two-fold: voltage drop Vdown due to the power cable (power supply cable PSC) and arc power Varc that drops due to arc discharge. In order to derive an appropriate output voltage Vout, the voltage required by two load elements, namely, the voltage drop Vdown in the power supply cable PSC and the arc power Varc dropped by the arc discharge, is estimated. A command voltage Vset to the welding power source 300 is determined based on the result of estimating the required voltage. Information specifying the determined command voltage Vset is input to the welding power source 300. A specific description will be given below. The calculation unit 404 derives the provisional output voltage Vaout based on the equation (1). Vaarc+Vadown+ΔV=Vaout (1) In equation (1), Vaarc is the set voltage when performing welding work, and corresponds to the arc voltage Varc that drops due to arc discharge. The arc voltage Varc that drops due to arc discharge is a value measured by welding system 1, so in the welding voltage feedback system, calculation unit 404 adjusts the correction term ΔV by feedback control so that this arc voltage Varc that drops due to arc discharge becomes equal to the tentative set voltage Vaarc when performing welding work. Vddown is the theoretical voltage drop due to the power supply cable, and is estimated based on the diameter and length of the power supply cable.

[0031] Calculation unit 404 obtains command voltage Vset corresponding to the derived temporary output voltage Vaout from the output characteristics of welding power source 300. Specifically, as shown by (1) in Fig. 4, command voltage Vset is obtained from temporary output voltage Vaout (output voltage Vout of the welding power source in Fig. 4). Returning to Fig. 1, the explanation will be continued. The processing unit 406 acquires information specifying the command voltage Vset from the calculation unit 404. The processing unit 406 creates command voltage information including the acquired information specifying the command voltage Vset. The processing unit 406 outputs the created command voltage information to the communication unit 402. Communication unit 402 acquires the command calculation information output by processing unit 406 and transmits the acquired command calculation information to 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 communication conversion of the encoder values ​​of each of the 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 communication conversion of the encoder values ​​of each of the one or more motors acquired. Processing unit 406 acquires information specifying the motor rotation value of each of one or more motors from calculation unit 404. Processing unit 406 outputs the acquired information specifying the motor rotation value of each of one or more motors to input / output unit 502 of relay device 500. The input / output unit 502 acquires information specifying the motor rotation value of each of the one or more motors output by the processing unit 406, and transmits the acquired information specifying the motor rotation value of each of the 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) that are realized by a processor such as a CPU executing a program stored in a storage unit (not shown). 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.

[0032] (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. The command receiving unit 302 may also communicate using a communication method such as a wired LAN. Specifically, the command receiving unit 302 receives information that specifies the command voltage Vset transmitted by the control device 400. Welding power source 300 determines the voltage (output voltage Vout) to be output by welding power source 300 from the output characteristics of welding power source 300 based on information specifying command voltage Vset received by command receiving unit 302. Welding power source 300 supplies the determined output voltage Vout to voltage supply cable PSC, thereby supplying power to welding robot 100. The length of power supply cable PSC is adjusted by wire feeder 200 based on the distance between welding robot 100 and wire feeder 200. Welding robot 100 performs welding using the power supplied by welding power source 300.

[0033] (Welding system 1 operation) 5 is a flow chart showing a first example of the operation of the welding system according to this embodiment. Referring to FIG. 5, a process for 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) Wire feeder 200 acquires the welding voltage value and outputs the acquired welding voltage value to relay device 500. (Step S3-1) In relay device 500 , input / output unit 502 acquires the welding voltage value output by wire feeder 200 . (Step S4-1) In relay device 500, A / D conversion unit 504 acquires the welding voltage value from input / output unit 502. A / D conversion unit 504 converts the acquired welding voltage value into digital data.

[0034] (Step S5-1) In relay device 500, processing unit 508 acquires the result of converting the welding voltage value into digital data from A / D conversion unit 504. 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 relay device 500, processing unit 508 outputs the created digital welding voltage value to communication unit 510. Communication unit 510 transmits the digital welding voltage value output by processing unit 508 to control device 400. (Step S7-1) In control device 400, communication unit 402 receives the digital welding voltage value transmitted by relay device 500. (Step S8-1) In control device 400, calculation unit 404 derives temporary output voltage Vaout based on equation (1). Since arc voltage Varc, which drops due to arc discharge, is a value measured by welding system 1, calculation unit 404 adjusts correction term ΔV by feedback control in the welding voltage feedback system so that arc voltage Varc, which drops due to arc discharge, becomes equal to temporary set voltage Vaarc when performing welding work. An example of this feedback control is PID control (Proportional-Integral-Differential Controller). Calculation unit 404 acquires information identifying the digital welding voltage value received by communication unit 402. Calculation unit 404 calculates command voltage Vset based on the acquired information identifying the digital welding voltage value.

[0035] (Step S9-1) In the control device 400, the processing unit 406 acquires the command voltage Vset from the calculation unit 404. The processing unit 406 outputs, to the communication unit 402, information specifying the acquired command voltage Vset. The communication unit 402 acquires the information specifying the command voltage Vset output by the processing unit 406, and transmits the acquired information specifying the command voltage Vset to the welding power source 300. (Step S10-1) In welding power source 300, command receiving unit 302 receives information that specifies command voltage Vset transmitted by 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 that specifies the command voltage Vset received by the command receiving unit 302. (Step S12-1) In the welding robot 100, the welding torch 102 discharges electricity using the output voltage Vout supplied by the welding power source 300.

[0036] 6 is a flow diagram showing Example 2 of the operation of the welding system according to this embodiment. Referring to FIG. 6, a process for 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 values ​​of each of the one or more motors, and outputs the acquired encoder values ​​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 values ​​of one or more motors output by the control unit 108, and outputs the acquired encoder values ​​of 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 values ​​of 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 values ​​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 values ​​of one or more motors to the control device 400.

[0037] (Step S5-2) In relay device 500, processing unit 508 acquires the encoder values ​​of each of one or more motors whose interfaces have been converted from communication conversion unit 506. Processing unit 508 creates a motor rotation value request including the encoder values ​​of each of one or more motors whose interfaces have been converted. (Step S6-2) In relay device 500, processing unit 508 outputs the created motor rotation value request to communication unit 510. Communication unit 510 transmits the motor rotation value request output by processing unit 508 to 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 calculation unit 404 acquires the motor rotation value request received by the communication unit 402. The calculation unit 404 calculates the motor rotation value based on the encoder values ​​of one or more motors whose interfaces have been converted and which are included in the acquired motor rotation value request.

[0038] (Step S9-2) In the control device 400, the processing unit 406 acquires information specifying the motor rotation value of each of the one or more motors from the calculation unit 404. The processing unit 406 creates a motor rotation value response including the acquired information specifying the motor rotation value of each of the 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 relay device 500, communication unit 510 receives the motor rotation value response transmitted by control device 400. (Step S11-2) In relay device 500, processing unit 508 acquires a motor rotation value response from communication unit 510. 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. Processing unit 508 outputs the acquired information specifying the motor rotation value of each of one or more motors to input / output unit 502. (Step S12-2) In welding robot 100, input / output unit 104 acquires information specifying the motor rotation value of each of one or more motors output by relay device 500. Control unit 108 acquires the information specifying the motor rotation value of each of one or more motors from input / output unit 104, and controls the operation of welding robot 100 based on the acquired information specifying the motor rotation value of each of one or more motors.

[0039] (Example of using Welding System 1) FIG. 7 is a diagram illustrating an example of use of the welding system according to this embodiment. FIG. 7 shows a floor plan of a building. In FIG. 7, the directions parallel to the floors are the X-axis and Y-axis, and the direction perpendicular to the X-axis and Y-axis is the Z-axis. Steel pipes SP-1, SP-2, SP-3, and SP-4 are arranged on the same floor of the building. An example of the length L1 in the Y-axis direction between steel pipes SP-1 and SP-4 (between steel pipes SP2 and SP-4) is 10 to 20 m. An example of the length L1 in the X-axis direction between steel pipes SP-1 and SP-2 (between steel pipes SP3 and SP-4) is 10 to 20 m.

[0040] In the welding system 1, the welding robot 100 is mounted so as to be able to slide on a guide rail GL-1 attached to a steel pipe SP-1. The relay device 500 is disposed in the center area of ​​the positions where the steel pipes SP-1, SP-2, SP-3, and SP-4 are disposed in the plane defined by the X-axis and the Y-axis. In other words, the relay device 500 is disposed in the center of the floor. Relay device 500 and control device 400 can be located at a distance of approximately 60 m to 100 m. Therefore, control device 400 and welding power source 300 may be located on the same floor as or on a different floor from that on which welding robot 100 and relay device 500 are located. In Fig. 7, wire feeder 200 (not shown) may be suspended from beam BE. After welding to steel pipe SP-1 is completed, welding to steel pipe SP-2 is performed. In preparation for welding to steel pipe SP-2, welding robot 100 is moved from steel pipe SP-1 to steel pipe SP-2. Here, as welding robot 100 moves, wire feeder 200 (not shown) also moves. Relay device 500 is located in the central area where steel pipes SP-1, SP-2, SP-3, and SP-4 are located, so its movement is not necessary. By arranging the relay device 500 in the central area of ​​the floor, it is possible to weld each of the multiple steel pipes arranged on the floor by moving the welding robot 100 without moving the relay device 500.

[0041] In the above-described embodiment, the welding robot 100 may acquire information specifying the temperature, such as the temperature distribution, acquired by a thermometer (not shown), and output the information specifying the acquired temperature to the relay device 500. In addition, the welding robot 100 may be configured so that the imaging unit 110 acquires either or both of image data acquired by imaging the welding state and information identifying the temperature acquired by the thermometer, and outputs either or both of the acquired image data and information identifying the temperature to the relay device 500. With this configuration, the user of the welding system can check the state of the welding by checking the image of the steel material being 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 this is not limiting. For example, the control device 400 and the relay device 500 may be connected wirelessly.

[0042] According to the welding system 1 of this embodiment, the welding system 1 includes a welding robot 100, a control device 400 that generates 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 generated by the control device 400 to the welding robot 100. With this configuration, relay device 500 is installed between welding robot 100 and control device 400, so that welding robot 100 and control device 400 can be installed at a distance from each other.

[0043] The welding robot 100 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 from the welding power source 300 to the welding robot 100. With this configuration, the welding wire is fed to the welding robot 100 by the wire feeder 200, thereby supplying welding power to the welding robot 100.

[0044] Welding robot 100 also includes welding torch 102. Welding robot 100 or wire feeder 200 measures the arc voltage of welding torch 102. Relay device 500 converts the arc voltage measured by welding robot 100 or wire feeder 200 into digital information and relays the result of converting the arc voltage into digital information to control device 400. Control device 400 derives a voltage drop in the arc voltage based on the result of converting the arc voltage into digital information relayed by relay device 500, and creates command voltage information for instructing welding power source 300 on a welding voltage based on the derived voltage drop. This configuration allows digital information to be transmitted between the relay device and the control device, allowing the relay device and the control device to be spaced apart. Ideally, the measurement point for measuring the arc voltage Varc would be at the welding torch 102, but this would become a noise source. Having the wire feeder 200 measure the arc voltage makes it possible to avoid placing the measurement point on the line between the welding robot 100 and the relay panel (relay device). Even if a separate measurement cable were provided, it would be routed by the welding robot 100, which would interfere with its operation. Having the wire feeder 200 measure the arc voltage allows the arc voltage to be measured without interfering with the welding robot 100.

[0045] Furthermore, welding robot 100 is equipped with one or more motors 112-1 to 112-n. Welding robot 100 acquires information specifying the rotation value of each of one or more motors 112-1 to 112-n. Relay device 500 performs communication conversion of the information specifying the rotation value of each of one or more motors 112-1 to 112-n acquired by welding robot 100. Control device 400 calculates the rotation value of each of one or more motors 112-1 to 112-n based on the result of communication conversion of the information specifying the rotation value of each of one or more motors 112-1 to 112-n. The relay device 500 acquires the calculation results of the rotation values ​​of one or more motors 112-1 to 112-n from the control device 400 and relays the acquired calculation results to the welding robot 100. With this configuration, the welding robot can be moved. An example of the motors 112-1 to 112-n is a servo motor. By configuring the system with a servo motor and an encoder, more precise speed control and position control becomes possible than with a welding robot configured with a stepping motor, thereby improving welding quality. Furthermore, by maintaining the portability of the welding system, which is usually a trade-off, the system can improve workability at construction sites.

[0046] The welding robot 100 also includes an imaging unit 110 that acquires image information of the steel material being welded, and an input / output unit 104 that acquires information specifying the temperature of the steel material. The relay device 500 acquires either or both of the image information acquired by the imaging unit 110 and the information specifying the temperature acquired by the input / output unit. With this configuration, the user of the welding system can check the state of the welding by checking the image of the steel material being welded by the welding robot and the temperature of the steel material.

[0047] According to relay device 500 of this embodiment, relay device 500 relays information between welding robot 100 and control device 400, which generates a control signal for controlling welding robot 100. Relay device 500 includes an A / D conversion unit 504 that converts the arc voltage measured by welding robot 100 into digital information, a processing unit 508 that generates 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 generated by processing unit 508 to control device 400. With this configuration, the relay device can relay the arc voltage obtained by measuring the welding robot to control device 400.

[0048] The welding robot 100 further includes a communication conversion unit 506 that performs communication conversion of information that identifies the rotation value of each of the one or more motors 112-1 to 112-n included in the welding robot 100. The processing unit 508 creates a motor rotation value request that includes the result of communication conversion of the information that identifies the rotation value of each of the one or more motors 112-1 to 112-n performed 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. Processing unit 508 relays information specifying the rotation value of each of one or more motors 112-1 to 112-n, which is included in the motor rotation value response received by communication unit 510, to welding robot 100. With this configuration, the relay device can relay information specifying the rotation value of each of one or more motors provided in the welding robot to the control device, and can relay the information specifying the rotation value of each of one or more motors transmitted by the relay device to the welding robot.

[0049] According to the welding method performed by the welding system of this embodiment, the welding method is performed 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 the steps of measuring the arc voltage of the welding torch 102, converting the arc voltage into digital information by the relay device 500, which is disposed near one steel pipe or between multiple steel pipes, relaying the converted digital information to the control device 400, deriving a voltage drop of the arc voltage based on the converted digital information, creating command voltage information for instructing a welding power source of a welding voltage based on the derived arc voltage, and outputting the created command voltage information to the welding power source 300, which supplies welding power for welding to the welding robot 100. With this configuration, the welding power source can supply a welding voltage to the welding robot based on the command voltage information output by the control device, thereby allowing each of one or more steel pipes to be welded.

[0050] The method further includes the steps of: welding robot 100 acquiring information specifying the rotational value of each of one or more motors 112-1 to 112-n; relay device 500 performing communication conversion of the information acquired by welding robot 100 specifying the rotational value of each of one or more motors 112-1 to 112-n; control device 400 calculating the rotational value of each of one or more motors 112-1 to 112-n based on the result of communication conversion of the information specifying the rotational value of each of one or more motors 112-1 to 112-n; relay device 500 acquiring the calculation results of the rotational value of each of one or more motors 112-1 to 112-n from control device 400 and relaying the acquired calculation results to welding robot 100; and welding robot 100 moving based on the calculation results. This configuration allows welding robot 100 to move.

[0051] According to the relay method executed by the relay device of this embodiment, the relay method is executed by relay device 500, which relays information between welding robot 100 and control device 400, which generates a control signal for controlling welding robot 100, and includes the steps of converting the arc voltage into digital information, creating a digital welding voltage value including the result of converting the arc voltage into digital information, and transmitting the digital welding voltage value to control device 400. With this configuration, relay device 500 can relay the arc voltage measured by welding robot 100 to control device 400.

[0052] A welding system according to one aspect of the present invention includes a portable welding robot (in an embodiment, welding robot 100) for welding steel pipes 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. The power supply cable PSC has one end connected to the stationary welding power source and the other end connected to the portable wire feeder, and supplies welding power from the stationary welding power source to the portable wire feeder. The first control cable CC01 has one end connected to the stationary control device and the other end connected to the portable relay device, and transmits control signals from the stationary control device to control the portable welding robot. The second control cable CC02 has one end connected to the portable relay device and the other end connected to the portable welding robot, and transmits a control signal for controlling the portable welding robot, which is relayed by the portable relay device. With this configuration, the portable relay device is installed between the portable welding robot and the stationary control device, so the portable welding robot and the stationary control device can be installed at a distance from each other.

[0053] The portable welding robot 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, and a first control cable transmits the arc voltage signal from the portable relay device to the stationary control device. The stationary control device calculates a voltage drop in 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. This configuration allows the portable welding robot and the stationary control device to be spaced apart, and also reduces the effects of noise (especially on the encoder signal) caused by the power supply cable.

[0054] The portable welding robot further includes a power cable that supplies power to the portable welding robot. One end of the power cable is connected to the portable relay device, and the other end is connected to the portable welding robot. This configuration reduces the complexity of handling the cable. Although the power cable that supplies power to the portable welding robot can also be a noise source, the noise impact of these cables is significantly smaller than 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.

[0055] The portable welding robot further includes an imaging unit provided on the portable welding robot and a camera cable that supplies power to the imaging unit. One end of the camera cable is connected to the portable relay device, and the other end is connected to the portable welding robot. This configuration reduces the complexity of cable handling. Although the camera cable that supplies power to the imaging unit can also be a noise source, the impact of noise from these cables is significantly smaller than that of power cables. Therefore, by connecting the camera cable to the portable welding robot via the portable relay device, the complexity of cable handling can be reduced.

[0056] The portable welding robot further includes a servo motor provided on the robot and an encoder cable for transmitting an encoder signal from the servo motor. One end of the encoder cable is connected to the portable relay device, and the other end is connected to the robot. Since the power supply cable that supplies welding power is a significant noise source, this configuration allows the power supply cable to be connected to both the stationary welding power source and the portable wire feeder without going through the portable relay device, thereby reducing the effect of noise generated in the power supply cable on the encoder signal.

[0057] A method for installing a welding system according to one aspect of the present invention is a method for installing a welding system including a stationary control device (in an embodiment, control device 400) that transmits digital signals, a portable relay device (in an embodiment, relay device 500) that is separate from the stationary control device and that converts the digital signals transmitted from the stationary control device into analog signals, and a portable welding robot (in an embodiment, welding robot 100) that is separate from the stationary control device and the portable relay device and that is driven in accordance with the analog signals converted by the portable relay device and that welds multiple steel pipes SP on the same floor of a building. The welding system installation method includes an installation step of installing a stationary control device in a building, a discrimination step of determining whether one of the devices in the welding system is a portable relay device or a portable welding robot, and a placement step of placing the device determined to be a portable relay device in the determination step in the center of a floor where multiple steel pipes are located, and placing the device determined to be a portable welding robot in the determination step on one of the multiple steel pipes.The installation step, discrimination step, and placement step are performed by, for example, a work robot.With this configuration, the portable welding robot can be driven in accordance with the analog signal converted by the portable relay device, and multiple steel pipes on the same floor of a building can be welded.

[0058] Although the embodiments have been described above, 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, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments are included within the scope and spirit of the invention, as well as within the scope of the inventions described in the claims and their equivalents.

[0059] The welding robot 100, the control device 400, and the relay device 500 described above may be implemented by a computer. In this case, a program for implementing the functions of each functional block is recorded on a computer-readable recording medium. The program recorded on this recording medium may be loaded into a computer system and executed by a CPU. The term "computer system" as used herein includes hardware such as an OS (Operating System) and peripheral devices. In addition, "computer-readable recording media" refers to portable media such as flexible disks, optical magnetic disks, ROMs, CD-ROMs, etc. "Computer-readable recording media" also includes storage devices such as hard disks built into computer systems.

[0060] Furthermore, the term "computer-readable recording medium" may include a medium that dynamically stores a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. Furthermore, the term "computer-readable recording medium" may also include a storage medium that stores a program for a certain period of time, such as a volatile memory within a computer system that is a server or client. The program may also be for implementing part of the functions described above. The program may also be capable of implementing the functions described above in combination with a program already stored in the computer system. The program may also be implemented using a programmable logic device. An example of a programmable logic device is an FPGA (Field Programmable Gate Array).

[0061] The above-described welding robot 100, control device 400, and relay device 500 each have a built-in computer. The processes of the above-described 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-described processes are performed by the computer reading and executing the program. Here, computer-readable recording media refers to magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, etc. Also, this computer program may be distributed to a computer via a communication line, and the computer that receives this distribution may execute the program. The program may also be a program for implementing some of the functions described above, or may be a so-called differential file (differential program) that can implement the functions described above in combination with a program already stored in the computer system. [Explanation of symbols]

[0062] 1. Welding System 100 welding robots 102 Welding Torch 104 Input / output section 108 Control Unit 110 Imaging unit 112-1,...,112-n motor 200 Wire Feeder 300 Welding Power Source 302 Order Department 400 control device 402 Communications Department 404 Arithmetic section 406 Processing Section 500 Repeater 502 Input / output section 504 A / D conversion section 506 Communication conversion unit 508 Processing section 510 Communications Department

Claims

1. Welding robots and a control device that generates a control signal for controlling the welding robot; a connecting device separate from the welding robot; a welding power source; a wire feeder connected to the welding power source and supplying welding power to the welding robot; a first cable having one end connected to the control device and the other end connected to the connection device; a second cable having one end connected to the connection device and the other end connected to the welding robot; A welding system comprising:

2. an imaging unit provided in the welding robot; a third cable having one end connected to the connection device and supplying power to the imaging unit; The welding system of claim 1 further comprising:

3. a motor provided in the welding robot; a fourth cable having one end connected to the connection device and transmitting a signal from the motor; The welding system of claim 1 further comprising:

4. the welding robot is a portable welding robot for welding steel pipes, the wire feeder is separate from the portable welding robot; the welding power source is separate from the portable welding robot and the wire feeder; the control device is separate from the portable welding robot and the wire feeder, The connection device is separate from the portable welding robot, the welding power source, and the control device.

4. The welding system according to claim 1, wherein the welding system comprises: a welding head;

Images