Welding apparatus and welding method

Abstract

To provide a welding apparatus and welding method that enables more effective multi-layer welding by updating the welding plan at the appropriate time. [Solution] The welding apparatus 100 includes a measuring unit 120 that measures welding locations on the surface of the steel pipe 50 while moving a sensor 12 along the outer circumference of the steel pipe 50, a welding plan generation unit 130 that generates or updates a welding plan based on the welding locations measured by the measuring unit 120, and a welding unit 140 that moves along the outer circumference of the steel pipe 50 and welds based on the welding plan generated or updated by the welding plan generation unit 130. The welding plan generation unit 130 generates or updates a welding plan according to a preset timing and / or according to the shape of the welding locations measured by the measuring unit 120.

Description

Technical Field

[0001] The present invention relates to a welding apparatus and a welding method.

Background Art

[0002] In recent years, steel pipe columns formed by connecting steel pipes by welding are used in large buildings such as high-rise buildings. When connecting steel pipes, a rail is arranged so as to go around the outer periphery of the steel pipes, and the connecting portions of the steel pipes are welded while a welding robot travels along the rail.

[0003] For example, Patent Document 1 discloses that multi-layer welding is realized by repeating the welding process through a sensing process, a cross-section estimation process and a target position setting process, and further discloses returning to the sensing process at a stage where a certain number of layers have been advanced in the welding process.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the welding process disclosed in Patent Document 1, since the process returns to the sensing process at the stage where a certain number of layers have been advanced, there is a problem that it is not possible to cope with a change in the target position that should be appropriately welded, for example, when bead sagging occurs in the initial stage. As a result, there is a possibility that appropriate multi-layer welding cannot be realized. On the other hand, if the process returns to the sensing process at a high frequency, the tact time will be extended, and this effect will be particularly significant when performing multi-layer welding with a large number of layers.

[0006] Therefore, the present invention aims to provide a welding apparatus and welding method that can update the welding plan at an appropriate time and achieve multi-layer welding more effectively. [Means for solving the problem]

[0007] A welding apparatus according to one aspect of the present invention is a welding apparatus that performs multi-layer welding of welding locations on the surface of a steel pipe while moving along the outer circumference of the steel pipe, comprising: a measuring unit that measures welding locations and / or welded locations on the surface of the steel pipe while moving a sensor along the outer circumference of the steel pipe; a welding plan generation unit that generates or updates a welding plan based on the welding locations measured by the measuring unit; and a welding unit that performs welding based on the welding plan generated or updated by the welding plan generation unit while moving along the outer circumference of the steel pipe, wherein the welding plan generation unit generates or updates a welding plan according to a preset timing and / or according to the shape of the welding locations measured by the measuring unit.

[0008] In this embodiment, the measurement unit measures the welding location while moving the sensor along the outer circumference of the steel pipe, the welding plan generation unit generates or updates a welding plan according to a preset timing and / or according to the shape of the welding location measured by the measurement unit, and the welding unit welds based on the welding plan generated or updated by the welding plan generation unit while moving along the outer circumference of the steel pipe. This makes it possible to update the welding plan at the appropriate timing and achieve multi-layer welding more effectively.

[0009] In the above embodiment, the preset timing may be at predetermined intervals among multiple welding passes in multilayer welding.

[0010] According to this embodiment, the welding plan generation unit updates the welding plan at predetermined intervals among multiple welding passes in multilayer welding, thereby enabling the welding plan to be appropriately updated according to the shape of the welding location.

[0011] In the above embodiment, the preset timing may be every predetermined number of layers among the multiple layers formed in multilayer welding.

[0012] According to this embodiment, the welding plan generation unit updates the welding plan for each predetermined number of layers among the multiple layers formed in multilayer welding, so that the welding plan can be appropriately updated according to the shape of the welding location for each formed layer.

[0013] In the above embodiment, the preset timing may be more frequent in the first half of the multilayer welding process than in the second half.

[0014] According to this embodiment, high-precision welding can be achieved in the first half of multi-layer welding by frequently updating the welding plan, and time can be reduced in the second half by reducing the frequency of updating the welding plan.

[0015] In the above embodiment, the welding plan generation unit may update the welding plan based on the predicted shape of the welding location predicted from the welding plan generated or updated by the welding plan generation unit and the measured shape of the welding location measured by the measurement unit.

[0016] According to this embodiment, the welding plan generation unit updates the welding plan based on the predicted shape and measured shape of the welding site, so that the welding plan can be updated more appropriately in response to changes in the shape of the welding site.

[0017] In the above embodiment, the welding plan generation unit may update the welding plan if the discrepancy between the predicted shape and the measured shape is greater than or equal to a threshold.

[0018] According to this embodiment, the welding plan generation unit updates the welding plan when the discrepancy between the predicted shape and the measured shape exceeds a threshold, thus enabling a more appropriate update of the welding plan when the amount of change in the shape of the welding area is large.

[0019] In the above embodiment, the system may further include a measurement necessity determination unit that determines whether or not to measure the welded area using a measurement unit, based on at least one of the welding voltage and welding current used to weld the area with the welded part.

[0020] According to this embodiment, the measurement necessity determination unit determines whether or not to measure the welded area using the measurement unit based on the welding voltage and welding current, thereby enabling the appropriate determination of the timing for measuring the welded area.

[0021] In the above embodiment, the measurement necessity determination unit may determine that the welded location should be measured by the measurement unit if the difference between at least one of the welding voltage and welding current of the welded location predicted from the welding plan generated or updated by the welding plan generation unit and at least one of the welding voltage and welding current used to weld the location by the welding unit is greater than or equal to a threshold.

[0022] According to this embodiment, the measurement necessity determination unit measures the welding location by the measurement unit when there is a large discrepancy between at least one of the welding voltage and welding current predicted from the welding plan and at least one of the actual welding voltage and welding current, thereby enabling a more appropriate determination of the timing for measuring the welding location.

[0023] A welding method according to one aspect of the present invention is a welding method performed by a welding apparatus that performs multi-layer welding of welding locations on the surface of a steel pipe while moving along the outer circumference of the steel pipe, and includes: a measurement step of measuring welding locations and / or welded locations on the surface of the steel pipe while moving a sensor along the outer circumference of the steel pipe; a welding plan generation step of generating or updating a welding plan based on the welding locations measured in the measurement step; and a welding step of welding based on the welding plan generated or updated in the welding plan generation step while moving along the outer circumference of the steel pipe, wherein the welding plan generation step generates or updates the welding plan according to a preset timing and / or according to the shape of the welding locations measured in the measurement step.

[0024] According to this aspect, in the measuring step, the welding point is measured while moving the sensor along the outer periphery of the steel pipe, and in the welding plan generation step, the welding plan is generated or updated in accordance with a preset timing and / or according to the shape of the welding point measured by the measuring unit, and in the welding step, welding is performed based on the welding plan generated or updated in the welding plan generation step while moving along the outer periphery of the steel pipe. Thereby, the welding plan can be updated at an appropriate timing, and multi-layer welding can be realized more appropriately. Effects of the Invention

[0025] According to the present invention, it is possible to provide a welding apparatus and a welding method capable of updating a welding plan at an appropriate timing to realize multi-layer welding more appropriately. Brief Description of the Drawings

[0026] [Figure 1] 1 is a schematic diagram showing the system configuration of a welding robot system 1 according to a first embodiment of the present invention. [Figure 2] FIG. 3 is a diagram showing a state in which two welding robots 10A and 10B can each travel over a half circumference of a steel pipe 50. [Figure 3] FIG. 2 is a functional block diagram showing each function of a welding apparatus 100 according to the first embodiment of the present invention. [Figure 4] FIG. 3 is a flowchart showing the procedure of a welding method M100 executed by the welding apparatus 100 according to the first embodiment of the present invention. [Figure 5] FIG. 7 is a flowchart showing the procedure of a welding method M101 executed by the welding apparatus 100 according to the first embodiment of the present invention. [Figure 6] FIG. 7 is a functional block diagram showing each function of a welding apparatus 200 according to a second embodiment of the present invention. [Figure 7] FIG. 7 is a flowchart showing the procedure of a welding method M200 executed by the welding apparatus 200 according to the second embodiment of the present invention. Modes for Carrying Out the Invention

[0027] The embodiments of the present invention will be described in detail below with reference to the drawings. The embodiments described below are merely examples of how to implement the present invention and are not intended to limit the scope of the invention. Furthermore, to facilitate understanding of the explanation, the same reference numerals are used for identical components in the drawings whenever possible, and redundant explanations may be omitted.

[0028] <First Embodiment> [Overview of the welding robot system] Figure 1 is a schematic diagram showing the system configuration of a welding robot system 1 according to the first embodiment of the present invention. As shown in Figure 1, the welding robot system 1 comprises a welding robot 10, a sensor monitoring device 20, a robot control device 30, a welding wire feeding device 40, and a welding power supply (not shown). The welding robot 10 is equipped with a welding torch 11 as an end effector and a laser profiler 12 as a sensor.

[0029] The welding robot system 1 connects steel pipes 50A and 50B by welding their outer circumferences (connecting portions 51) to form steel pipe columns (steel columns) used in large buildings such as skyscrapers.

[0030] Steel pipes 50A and 50B form steel pipe columns such as column columns and four-sided box columns. The steel pipes 50A and 50B are connected by so-called groove welding at the connecting portion 51 of the steel pipes 50A and 50B while they are temporarily fixed by erection pieces 70. Hereinafter, steel pipes 50A and 50B as a whole may be referred to as steel pipe 50.

[0031] The welding robot 10 is connected to a robot control device 30 via a cable and performs arc welding based on operation commands from the robot control device 30. For example, the welding robot 10 may perform welding while traveling along a rail 60 that is arranged to circle the steel pipe 50A along its outer circumference. A welding wire is fed from a welding torch 11 provided at the tip of the welding robot 10, and arc welding is performed by moving the tip of the welding torch 11 along the connecting portion 51 of the steel pipes 50A and 50B and generating an arc between the steel pipes 50A and 50B.

[0032] The welding torch 11 is connected to a welding power source via a cable and receives welding voltage and welding current to the welding wire. In arc welding, when the welding wire is momentarily brought into contact with the metal material (in this case, the connecting portion 51 in the steel pipes 50A and 50B) and current is applied, an arc discharge is generated between the welding wire and the connecting portion 51, and welding is performed by melting the welding wire and the connecting portion 51 with the heat of the generated arc.

[0033] The laser profiler 12 irradiates the object to be sensed with laser light and measures its shape based on the reflected light. For example, the laser profiler 12 may be equipped with a laser light source, irradiation and receiving lenses, and a camera (CMOS), and measures the shape of the weld by irradiating the welded area with laser light, imaging the reflected light with the CMOS, and measuring the shape of the welded area.

[0034] The sensor monitoring device 20 controls and monitors the laser profiler 12 attached to the welding robot 10. For example, the sensor monitoring device 20 may control the light emitted from the laser light source of the laser profiler 12, monitor the light received by the laser profiler 12, or acquire profile data obtained by the laser profiler 12.

[0035] The robot control device 30 is a device that controls the welding robot 10. The robot control device 30 controls the welding robot 10, the sensor monitoring device 20, the welding wire feeding device 40, and the welding power supply, for example, based on a work program. Here, the work program includes teaching data that has been pre-programmed and generated so that the welding robot 10 welds the connecting portion 51 while traveling along the rail 60.

[0036] For example, the work program (teaching data) may include operational information of the welding robot 10, such as its position, posture, and movement speed; information regarding the feeding of the welding wire; and information regarding welding conditions, such as welding voltage, welding current, welding speed, and welding time. Furthermore, this information included in the work program (teaching data) may be set by an operator using an operating device such as a teach pendant, or by actually operating the welding robot 10.

[0037] Furthermore, the robot control device 30 controls the welding robot 10 (welding torch 11) based on the generated (updated) welding plan to ensure that the tip of the welding torch 11 is properly positioned at the welding location. Details regarding the welding plan will be described later.

[0038] The welding wire feeding device 40 is controlled by the robot control device 30 and, for example, feeds a predetermined length of welding wire in the forward direction (the direction from the tip of the welding torch toward the connecting portion 51 of the steel pipes 50A and 50B) at a predetermined feeding speed, or feeds it in the reverse direction.

[0039] The welding power supply is connected via a cable to the welding robot 10 (welding torch 11) and the welding wire feeding device 40, and supplies welding voltage and welding current to the welding torch 11 in the welding robot 10 based on commands from the robot control device 30.

[0040] In this manner, the welding robot system 1 measures the shape of the welding area by sensing the connecting portion 51 using a laser profiler 12 while the welding robot 10 travels along the rail 60 around the steel pipe 50. Then (separately), the welding robot 10 travels along the rail 60 around the steel pipe 50 and welds the welding area using a welding torch 11 according to the measured shape of the welding area.

[0041] Although the welding robot system 1 was equipped with one welding robot 10, it may be equipped with multiple welding robots. For example, it may be equipped with two welding robots, and each of the two welding robots may travel around half the circumference of the steel pipe 50 while welding the connecting portion 51 of the steel pipes 50A and 50B.

[0042] Figure 2 shows how two welding robots 10A and 10B can each travel half the circumference of a steel pipe 50. As shown in Figure 2, welding robot 10A can move along the rail 60 in the range RA from position A1 to position A2, and welding robot 10B can move along the rail 60 in the range RB from position B1 to position B2. Note that in Figure 2, the sensor monitoring device, robot control device, welding wire feeding device, etc. connected to the two welding robots 10A and 10B are omitted.

[0043] The welding robot 10A, for example, travels along the rail 60 on the outer circumference of the steel pipe 50 from position A1 to position A2 (or from position A2 to position A1), and uses a laser profiler 12 to sense the connecting portion 51 of the steel pipe 50 corresponding to the range RA from position A1 to position A2, thereby measuring the shape of the welding location. Then, the welding robot 10A, for example, travels along the rail 60 on the outer circumference of the steel pipe 50 from position A1 to position A2 (or from position A2 to position A1), and uses a welding torch 11 to weld the connecting portion 51 of the steel pipe 50 corresponding to the range RA from position A1 to position A2, according to the measured shape of the welding location.

[0044] Similarly, the welding robot 10B travels along the rail 60 on the outer circumference of the steel pipe 50 from position B1 to position B2 (or from position B2 to position B1), for example, and uses the laser profiler 12 to sense the connecting portion 51 of the steel pipe 50 corresponding to the range RB from position B1 to position B2, thereby measuring the shape of the welding location. Then, while traveling along the rail 60 on the outer circumference of the steel pipe 50 from position B1 to position B2 (or from position B2 to position B1), the welding robot 10B uses the welding torch 11 to weld the connecting portion 51 of the steel pipe 50 corresponding to the range RB from position B1 to position B2, according to the measured shape of the welding location.

[0045] In this manner, in the welding robot system 1, two welding robots 10A and 10B each travel halfway around the steel pipe 50, measuring the shape of the welding points of the connecting portions 51 around the entire circumference of the steel pipe 50, and welding the connecting portions 51 around the entire circumference of the steel pipe 50. Hereinafter, welding robots 10A and 10B may be collectively referred to as welding robot 10.

[0046] [Configuration of welding equipment] Figure 3 is a functional block diagram showing the functions of a welding apparatus 100 according to the first embodiment of the present invention. As shown in Figure 3, the welding apparatus 100 has a functional configuration comprising a robot control unit 110, a measurement unit 120, a welding plan generation unit 130, and a welding unit 140. The welding robot 10 travels along the rail 60 around the outer circumference of the steel pipe 50, and measures the shape of the welding area using a laser profiler 12, and then welds the measured welding area using a welding torch 11.

[0047] Of these functions, for example, the robot control unit 110 is a function realized by the robot control device 30. The measurement unit 120 is a function realized by the sensor monitoring device 20 and the laser profiler 12, and the welding unit 140 is a function realized by the welding wire feeding device 40, the welding power supply and the welding robot 10 (welding torch 11). The measurement unit 120 may have the function of controlling and monitoring the laser profiler 12 to acquire profile data provided in either the sensor monitoring device 20 or the robot control device 30, or it may be provided in a distributed (coordinated) manner across the sensor monitoring device 20 and the robot control device 30.

[0048] The robot control unit 110 controls the operation of the welding robot 10. For example, the robot control unit 110 controls the welding robot 10 to travel along the rail 60 around the outer circumference of the steel pipe 50. Based on the measured shape of the welding area (profile data) and the work program (teaching data), the robot control unit 110 controls the welding robot 10 to travel along the rail 60 around the outer circumference of the steel pipe 50 and to weld the welding area using the welding torch 11.

[0049] The measurement unit 120 measures the weld locations and / or welded locations on the surface of the steel pipe 50 while moving the laser profiler 12 (sensor) along the outer circumference of the steel pipe 50. For example, the measurement unit 120 measures the weld locations using the laser profiler 12 while moving the welding robot 10 along the rail 60 along the outer circumference of the steel pipe 50, and acquires the shape of the weld locations. The weld locations may be, for example, the connecting portion 51 between steel pipe 50A and steel pipe 50B before welding, or, in the case of multi-layer welding of the connecting portion 51, the connecting portion 51 may be partially welded (multi-layer welding is not yet complete) after some of the multiple welding passes have been executed.

[0050] Furthermore, when the measurement unit 120 measures the welding location using the laser profiler 12 while moving the welding robot 10 along the rail 60 on the outer circumference of the steel pipe 50, the welding robot 10 may be moved in either the welding direction or the return direction opposite to the welding direction. When measuring the welding location while moving the welding robot 10 in the welding direction, the welding robot 10 measures the shape of the welding location while actually moving in the welding direction, so the shape of the welding location can be measured with higher precision. On the other hand, when measuring the welding location while moving the welding robot 10 in the return direction, for example, in the case of multi-layer welding, the welding robot 10 can measure the shape of the welding location when it returns to the welding start position after actually moving in the welding direction and welding.

[0051] Whether the welding robot 10 measures the welding location while moving in the welding direction or the return direction may be predetermined, or it may be set by the user using an operating device.

[0052] The welding plan generation unit 130 generates or updates a welding plan based on the welding location measured by the measurement unit 120. For example, the welding plan generation unit 130 generates or updates a welding plan that includes detailed information on multiple welding passes in multilayer welding, based on the shape (profile data) of the welding location measured using the laser profiler 12. More specifically, the position of the welding torch 11 may be set (adjusted) so that it is appropriately located at the welding location according to the shape of the welding location, and furthermore, other information related to welding conditions may also be set (adjusted).

[0053] The welding plan generation unit 130 generates or updates a welding plan according to a preset timing and / or according to the shape of the welding location measured by the measurement unit 120. For example, when multi-layer welding is performed on the connecting portion 51 between steel pipe 50A and steel pipe 50B, the welding plan generation unit 130 generates a welding plan when welding is performed using a welding robot 10.

[0054] Furthermore, the welding plan generation unit 130 may update the welding plan at predetermined intervals among the multiple welding passes in multilayer welding. Specifically, this may be every time, every two times, or every ten times. Moreover, the welding plan may be updated at different frequencies, such as every two times in the first half and every ten times in the second half of the multiple welding passes in multilayer welding. By updating the welding plan at a high frequency in the first half of multilayer welding, welding can be performed with high precision, while reducing the frequency of welding plan updates in the second half of multilayer welding can shorten the welding time.

[0055] Furthermore, the welding plan generation unit 130 may update the welding plan according to the shape of the weld area (profile data) actually measured using the laser profiler 12. Specifically, the welding plan may be updated when the amount of change in the shape of the weld area is large (above a threshold), or when there is a large discrepancy between the predicted shape of the weld area predicted from the welding plan and the measured shape of the weld area actually measured using the laser profiler 12 (above a threshold). This makes it possible to appropriately update the welding plan in accordance with changes in the shape of the weld area when executing multiple welding passes in multilayer welding.

[0056] The welding area 140 moves along the outer circumference of the steel pipe 50 and is welded based on a welding plan generated or updated by the welding plan generation unit 130. For example, the welding robot 10 travels along the rail 60 around the outer circumference of the steel pipe 50 based on the work program (teaching data) and the welding plan generated or updated by the welding plan generation unit 130, and the welding area is welded using the welding torch 11. Here, since the welding plan is appropriately updated by the welding plan generation unit 130, the welding torch 11 can be appropriately positioned at the welding location according to the shape of the welding area, thus enabling more appropriate welding.

[0057] [Welding Method] Figure 4 is a flowchart showing the steps of welding method M100 performed by welding apparatus 100 according to the first embodiment of the present invention. As shown in Figure 4, welding method M100 includes steps S110 to S180.

[0058] In step S110, when multi-layer welding is performed on the connecting portion 51 of steel pipes 50A and 50B, the initial (first half) welding is performed manually by the worker. Steel pipes 50A and 50B are tack-fastened and connected by an erection piece 70, and the worker welds the connecting portion 51 of steel pipes 50A and 50B while avoiding the erection piece 70.

[0059] In step S120, the erection piece 70 is removed. In step S110, when the steel pipe 50A and the steel pipe 50B are connected to a certain extent by manual welding by an operator, the erection piece 70 is removed. After the erection piece 70 is removed, welding is performed by the welding robot 10. The welding robot 10 does not need to consider avoiding the erection piece 70 when positioning the tip of the welding torch 11 at the welding position, and automatic welding can be easily performed.

[0060] In step S130, the origin, which will serve as the reference position for the welding robot 10, is set. For example, position A1 may be set as the origin, which will serve as the reference position for the welding robot 10A shown in Figure 2, and the robot control unit 110 may move the welding robot 10A to position A1. Here, position A1 is set as the welding start position for the welding robot 10A, and position A2 is set as the welding end position.

[0061] In step S140, the welding plan generation unit 130 determines whether or not to generate (update) a welding plan for multi-layer welding. Specifically, the welding plan generation unit 130 determines whether or not to generate (update) a welding plan for multi-layer welding of the connecting portion 51 between steel pipe 50A and steel pipe 50B. Here, the welding plan is detailed information of multiple welding paths in multi-layer welding, and includes, for example, the position of the welding torch 11 and other information regarding welding conditions.

[0062] If a welding plan has not been generated (for example, before welding by the welding robot 10), it is determined to generate a welding plan and the process proceeds to step S150 ("Yes" in step S140).

[0063] Furthermore, if a welding plan has been generated, and the joint portion 51 between steel pipe 50A and steel pipe 50B is to be multi-layer welded, and some of the welding passes among the multiple welding passes have been executed, resulting in partial welding (multi-layer welding is not yet complete), it may be determined to update the welding plan at a preset timing ("Yes" in step S140). The preset timing may be, for example, every time, every two times, or every ten times for the multiple welding passes. Moreover, even in the middle of multi-layer welding, the user may select (set) to update the welding plan, or they may change the preset timing.

[0064] On the other hand, if it is determined in step S140 that a welding plan should not be generated (updated), the process proceeds to step S170 ("No" in step S140).

[0065] In step S150, the measurement unit 120 measures the welding location (measurement step). Specifically, while the robot control unit 110 moves the welding robot 10 along the outer circumference of the steel pipe 50, the measurement unit 120 measures the welding location using the laser profiler 12 attached to the welding robot 10.

[0066] In step S160, the welding plan generation unit 130 generates (updates) a welding plan based on the welding location measured in step S150 (welding plan generation step). Specifically, the welding plan generation unit 130 generates (updates) a welding plan that includes information such as the position of the welding torch 11 and welding conditions, based on the shape of the welding location (profile data) measured using the laser profiler 12.

[0067] In step S170, the welding area 140 is welded based on the welding plan generated (updated) in step S160 (welding step). Specifically, the welding robot 10 is moved along the outer circumference of the steel pipe 50 by the robot control unit 110, and the welding area 140 is welded using the welding torch 11 based on the welding plan generated (updated) in step S160.

[0068] In step S180, the welding apparatus 100 determines whether welding is complete or not. If welding is complete ("Yes" in step S180), the process ends. If welding is not complete ("No" in step S180), the process returns to step S140 and repeats steps S140 to S180 until welding is complete. Specifically, the welding apparatus 100 welds the connecting portion 51 by moving the welding robot 10 along the rail 60 to the outer circumference of the steel pipe 50 based on the work program and the welding plan generated (updated) in step S160. If multi-layer welding with multiple welding passes is completed ("Yes" in step S180), the process ends. If welding is not complete ("No" in step S180), the process returns to step S140 to execute the next welding pass and repeats steps S140 to S180 until welding is complete.

[0069] In welding method M100 shown in Figure 4, the welding plan was updated according to a predetermined timing ("Yes" in step S140), the shape of the welding area was measured (step S150), and the welding plan was updated (step S160). However, for example, the decision on whether or not to update the welding plan could be made based on the measured shape of the welding area.

[0070] Figure 5 is a flowchart showing the procedure of welding method M101 performed by the welding apparatus 100 according to the first embodiment of the present invention. As shown in Figure 5, welding method M101, compared to welding method M100 shown in Figure 4 above, determines in step S141 whether or not to generate (update) a welding plan according to the shape of the welding location measured in step S150.

[0071] Steps S110 to S130 are the same process as welding method M100 shown in Figure 4. Next, in step S150, the measurement unit 120 measures the welding location (measurement step). Specifically, while the robot control unit 110 moves the welding robot 10 along the outer circumference of the steel pipe 50, the measurement unit 120 measures the welding location using the laser profiler 12 attached to the welding robot 10.

[0072] Then, in step S141, the welding plan generation unit 130 determines whether or not to generate (update) a welding plan according to the shape of the welding location measured in step S150. Specifically, the welding plan generation unit 130 may determine to update the welding plan based on the shape of the welding location (profile data) actually measured using the laser profiler 12, if the amount of change in the shape of the welding location is large (above a threshold).

[0073] Furthermore, the welding plan generation unit 130 may determine to update the welding plan if there is a large discrepancy (above a threshold) between the predicted shape of the welding location predicted from the welding plan and the measured shape of the welding location actually measured using the laser profiler 12. Here, when comparing the predicted shape and the measured shape, the welding plan generation unit 130 may determine the degree of discrepancy between the predicted shape and the measured shape by using, for example, the Procrustes distance calculated from the sum of the squares of the differences between the two using Procrustes analysis.

[0074] If it is determined in step S141 to generate (update) the welding plan, the process proceeds to step S160 ("Yes" in step S141). If it is determined in step S140 not to generate (update) the welding plan, the process proceeds to step S170 ("No" in step S141).

[0075] Step S160 is the same process as welding method M100 shown in Figure 4, and the welding plan generation unit 130 generates (updates) a welding plan based on the welding locations measured in step S150 (welding plan generation step).

[0076] Furthermore, the shape of the welding area may be measured again with high precision before generating (updating) the welding plan in step S160. In other words, when measuring the shape of the welding area in step S150, it is done roughly in a short time, and if it is determined in step S141 to generate (update) the welding plan, the shape of the welding area is measured again with high precision. When generating (updating) the welding plan, an appropriate welding plan is generated (updated) by measuring the shape of the welding area again with high precision, while when not generating (updating) the welding plan, the measurement of the shape of the welding area in the preceding step S150 is done in a short time, thus shortening the overall cycle time.

[0077] Step S170 is the same process as welding method M100 shown in Figure 4, and the welded part 140 is welded based on the welding plan generated (updated) in step S160 (welding step). Specifically, if it was determined in step S141 to generate (update) the welding plan ("Yes" in step S141), the welded part 140 is welded based on the welding plan generated (updated) immediately before. However, if it was determined in step S141 not to generate (update) the welding plan ("No" in step S141), the welded part 140 is welded based on the welding plan generated (updated) last time.

[0078] Step S180 is the same process as welding method M100 shown in Figure 4. The welding apparatus 100 determines whether welding is complete or not. If welding is complete ("Yes" in step S180), it terminates the process. If welding is not complete ("No" in step S180), it returns to the process in step S150 and repeats steps S150, S141, and S160-S180 until welding is complete.

[0079] Furthermore, in step S141, a decision is made as to whether or not to generate (update) the welding plan according to the shape of the welding location that was actually measured. However, regardless of this decision, the welding plan may be generated (updated) at a predetermined timing (for example, every predetermined number of welding passes in multi-layer welding).

[0080] As described above, according to the welding apparatus 100 and welding methods M100, M101 of the first embodiment of the present invention, the measurement unit 120 measures the welding locations while moving the laser profiler 12 along the outer circumference of the steel pipe 50, and the welding plan generation unit 130 updates the welding plan at predetermined intervals among the multiple welding passes in multilayer welding, or updates the welding plan according to the shape of the welding locations actually measured by the measurement unit 120. As a result, the robot control unit 110 moves the welding robot 10 along the outer circumference of the steel pipe 50, and the welding unit 140 can weld the welding locations based on the appropriately updated welding plan. As a result, multilayer welding can be achieved more appropriately.

[0081] In this embodiment, the welding plan generation unit 130 was described as updating the welding plan at predetermined intervals among multiple welding passes in multilayer welding. However, the welding plan may also be updated at predetermined intervals among multiple layers formed in multilayer welding. Specifically, the welding plan can be updated appropriately according to the shape of the welding location on a layer-by-layer basis, such as every 1 layer, every 2 layers, or every 5 layers, in multilayer welding.

[0082] Furthermore, in multilayer welding, the welding plan may be updated at different frequencies, such as every two layers in the first half and every five layers in the second half. By updating the welding plan frequently in the first half, high-precision welding can be performed, while reducing the frequency of welding plan updates in the second half of multilayer welding can shorten the welding time.

[0083] In this embodiment, the first few welding passes (the first half of the welding process) in multilayer welding were performed manually by an operator, and after the erection piece 70 was removed, automatic welding was performed by the welding robot 10. However, this is not the only option. For example, automatic welding by the welding robot 10 could be performed while avoiding the erection piece 70 for the first few welding passes, and there is no restriction on manual welding by an operator after the erection piece 70 has been removed.

[0084] <Second Embodiment> Next, a second embodiment of the present invention will be described. In the second embodiment, descriptions of matters common to the first embodiment will be omitted or simplified, and the differences from the first embodiment will be described in detail. The second embodiment differs from the first embodiment in that it determines whether or not to measure the shape of the welding area using an arc sensor.

[0085] Figure 6 is a functional block diagram showing the functions of the welding apparatus 200 according to the second embodiment of the present invention. As shown in Figure 6, the welding apparatus 200 differs from the welding apparatus 100 according to the first embodiment of the present invention, which was described using Figure 3, in that it includes an arc sensor 21 for detecting the welding voltage and welding current during welding, and a measurement necessity determination unit 210 as a functional configuration.

[0086] The measurement necessity determination unit 210 determines whether or not to measure the welded area with the measurement unit 120 based on at least one of the welding voltage and welding current when the welding robot 10 is moved along the outer circumference of the steel pipe 50 and the welding area is welded by the welding unit 140. For example, when the welding robot 10 is moved along the outer circumference of the steel pipe 50 by the robot control unit 110 and the welding area is welded by the welding unit 140, the arc sensor 21 detects the welding voltage and welding current during welding. The measurement necessity determination unit 210 determines whether or not to measure the welded area with the measurement unit 120 based on at least one of the welding voltage and welding current detected by the arc sensor 21.

[0087] The measurement necessity determination unit 210 may determine that the welded area should be measured by the measurement unit 120 if the change in at least one of the welding voltage and welding current detected by the arc sensor 21 is large (above a threshold).

[0088] Furthermore, the measurement necessity determination unit 210 may determine that the welded area should be measured by the measurement unit 120 if there is a large discrepancy (above a threshold) between at least one of the welding voltage and welding current of the welded area predicted from the welding plan generated or updated by the welding plan generation unit 130 and at least one of the welding voltage and welding current actually detected by the arc sensor 21.

[0089] More specifically, the welding robot 10 is moved along the outer circumference of the steel pipe 50 to weld the welding points of the connecting portion 51 in the steel pipes 50A and 50B. While welding these points using the welding torch 11, voltage and / or current values ​​are acquired, for example, at the lower end, center, and upper end positions of the weaving.

[0090] Then, a triangle is generated by plotting the voltage or current value at the reference position. For example, using the lower end position of the weaving as the reference value, the distance from the lower end position of the weaving is plotted on the horizontal axis, and the voltage or current value is plotted on the vertical axis. The voltage or current values ​​obtained at the lower end position, the center position, and the upper end position of the weaving are plotted, and a triangle is generated based on these three plotted points.

[0091] The triangle predicted from the welding plan generated or updated by the welding plan generation unit 130 may be compared with the triangle based on the welding voltage or welding current actually detected by the arc sensor 21. The measurement necessity determination unit 210 may determine that the welded area should be measured by the measurement unit 120 if the difference between the two is large (above a threshold). When comparing the two, the measurement necessity determination unit 210 may, for example, compare the centroid positions of each triangle and determine that the welded area should be measured by the measurement unit 120 if the distance between them is large (above a threshold).

[0092] Figure 7 is a flowchart showing the procedure of welding method M200 performed by welding apparatus 200 according to the second embodiment of the present invention. As shown in Figure 7, welding method M200 differs from welding method M100 according to the first embodiment of the present invention, which was described using Figure 4, in that it includes a step S210 in which it determines whether or not to measure the welding location based on the welding voltage or welding current actually detected by the arc sensor 21.

[0093] Steps S110 to S130 are the same process as welding method M100 shown in Figure 4. Next, in step S210, the measurement necessity determination unit 210 determines whether or not to measure the welding location by the measurement unit 120 (measurement necessity determination step).

[0094] As a specific example, when the welding robot 10 is moved along the outer circumference of the steel pipe 50 by the robot control unit 110, and the welding area is welded using the welding torch 11 by the welding unit 140, the measurement necessity determination unit 210 uses the arc sensor 21 to detect the welding voltage and / or welding current during the welding.

[0095] Then, if the measurement necessity determination unit 210 determines that the welded area should be measured by the measurement unit 120 if there is a large discrepancy (above a threshold) between at least one of the welding voltage and welding current of the welded area predicted from the welding plan and at least one of the welding voltage and welding current actually detected by the arc sensor 21, it proceeds to step S150 ("Yes" in step S210). On the other hand, if the discrepancy between the two is not large (below a threshold), the measurement necessity determination unit 210 determines that the measurement should not be performed by the measurement unit 120 and proceeds to step S170 ("No" in step S210).

[0096] In step S150, since it was determined in step S210 that the measurement unit 120 should measure the welding location, the measurement unit 120 measures the welding location (measurement step).

[0097] Steps S160 and S170 are the same process as welding method M100 shown in Figure 4.

[0098] Step S180 is the same process as welding method M100 shown in Figure 4. The welding apparatus 100 determines whether welding is complete or not. If welding is complete ("Yes" in step S180), it terminates the process. If welding is not complete ("No" in step S180), it returns to the process in step S210 and repeats the processes in steps S210, S150 to S180 until welding is complete.

[0099] As described above, according to the welding apparatus 200 and welding method M200 of the second embodiment of the present invention, the measurement necessity determination unit 210 determines whether or not to measure the welded area with the measurement unit 120 based on at least one of the welding voltage and welding current of the welded area predicted from the welding plan and at least one of the welding voltage and welding current actually detected by the arc sensor 21. This makes it possible to measure the welded area with the measurement unit 120 at a more appropriate timing, thereby achieving proper welding while shortening the time required for multilayer welding.

[0100] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The elements, arrangement, materials, conditions, shapes, and sizes of the embodiments are not limited to those exemplified and can be modified as appropriate. Furthermore, it is possible to partially substitute or combine the configurations shown in different embodiments. [Explanation of Symbols]

[0101] 1...Welding robot system, 10, 10A, 10B...Welding robot, 11...Welding torch, 12...Laser profiler (sensor), 20...Sensor monitoring device, 21...Arc sensor, 30...Robot control device, 40...Welding wire feeding device, 50, 50A, 50B...Steel pipe, 51...Connecting part, 60...Rail, 70...Erection piece, 100, 200...Welding equipment, 110...Robot control unit, 120...Measurement unit, 130...Welding plan generation unit, 140...Welding unit, 210...Measurement necessity determination unit, A1, A2, B1, B2...Position, RA, RB...Range, M100, M101, M200...Welding method, S110~S180, S210...Each step of welding method M100, M101, M200

Claims

1. A welding apparatus that moves along the outer circumference of a steel pipe and performs multi-layer welding of welding points on the surface of the steel pipe, A measuring unit that measures the welding locations and / or welded locations on the surface of the steel pipe while moving the sensor along the outer circumference of the steel pipe, A welding plan generation unit generates or updates a welding plan based on the welding location measured by the measurement unit, A welding section that moves along the outer circumference of the steel pipe and performs welding based on the welding plan generated or updated by the welding plan generation unit, The welding plan generation unit generates or updates the welding plan according to a preset timing and / or according to the shape of the welding location measured by the measurement unit. Welding equipment.

2. The aforementioned preset timing is every predetermined number of welding passes in the multilayer welding process. The welding apparatus according to claim 1.

3. The aforementioned preset timing is every predetermined number of layers among the multiple layers formed in the multilayer welding. The welding apparatus according to claim 1.

4. The aforementioned preset timings are more frequent in the first half of the multilayer welding process than in the second half. The welding apparatus according to claim 2 or 3.

5. The welding plan generation unit updates the welding plan based on the predicted shape of the welding location predicted from the welding plan generated or updated by the welding plan generation unit and the measured shape of the welding location measured by the measurement unit. The welding apparatus according to claim 1.

6. The welding plan generation unit updates the welding plan if the discrepancy between the predicted shape and the measured shape exceeds a threshold. The welding apparatus according to claim 5.

7. The system further includes a measurement necessity determination unit that determines whether or not to measure the welded area using the measurement unit, based on at least one of the welding voltage and welding current used to weld the area with the welded part. The welding apparatus according to claim 1.

8. The measurement necessity determination unit determines that the welded location should be measured by the measurement unit if the difference between at least one of the welding voltage and welding current of the welded location predicted from the welding plan generated or updated by the welding plan generation unit and at least one of the welding voltage and welding current used to weld the location by the welding unit is greater than or equal to a threshold. The welding apparatus according to claim 7.

9. A welding method performed by a welding apparatus that moves along the outer circumference of a steel pipe and performs multi-layer welding of welding points on the surface of the steel pipe, A measurement step of measuring the welding locations and / or welded locations on the surface of the steel pipe while moving the sensor along the outer circumference of the steel pipe, A welding plan generation step that generates or updates a welding plan based on the welding location measured in the measurement step, A welding step includes moving along the outer circumference of the steel pipe and welding based on the welding plan generated or updated in the welding plan generation step, In the welding plan generation step, the welding plan is generated or updated according to a predetermined timing and / or according to the shape of the welding location measured in the measurement step. Welding method.

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