Robot system for welding steel pipe columns

Abstract

To provide a welding robot system for steel pipe column capable of performing stable welding of an upper steel pipe column and a lower steel pipe column, even when a plurality of welding robots are used.SOLUTION: A welding robot system includes: a plurality of multi-joint robots 80 for welding an upper steel pipe column 10 and a lower steel pipe column 20; and a control device 40 for controlling the operation of multi-joint robots 80A, 80B, and execution and stop of the welding. When start of welding of any one of the multi-joint robots 80 is not detected out of the plurality of multi-joint robots 80, after a welding execution part 44 of the control device 40 allows the other multi-joint robot 80 to execute the welding to an interruption position, it continues the interruption of the welding of the multi-joint robot 80 until the welding of the multi-joint robot 80 in which the start is not detected is started.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a welding robot system for steel pipe columns that welds an upper steel pipe column and a lower steel pipe column.

Background Art

[0002] As this type of technology, for example, Patent Document 1 proposes a welding robot for steel pipe columns that welds an upper steel pipe column and a lower steel pipe column while supplying a molten welding material to the groove between the upper steel pipe column and the lower steel pipe column.

[0003] Specifically, this welding robot connects the erection pieces with a jig, performs initial welding on the temporarily fixed upper steel pipe column and lower steel pipe column, and after removing the jig, further performs welding.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, for example, when welding an upper steel pipe column and a lower steel pipe column along a groove using a plurality of welding robots exemplified in Patent Document 1 or the like, the arc for welding of one welding robot may not be generated successfully. In such a case, since the welding robot for which the arc is not generated cannot start welding, it remains in a standby state at that position until the arc is generated. In this state, when other welding robots move along the groove for welding, there is a risk that other welding robots may come into contact with the welding robot that cannot start welding, or that the welding may not be performed as designed.

[0006] In addition, if welding is continued only with other welding robots capable of welding, it is conceivable that there will be a bias in the way strain enters the welded part between the part that has been welded first and the other parts. As a result, there is a risk that unnecessary inclination will occur in the steel pipe column after welding, or that surplus stress will act on it.

[0007] In addition to this, if welding is continued only with other welding robots capable of welding, the bead (weld layer) that has been welded first will become thick, and a step may occur between the welding path of the welding robot that could not perform welding. As a result, when the welding robot that could not perform welding resumes welding, there is a risk that the molten metal will drip or the welded part will become irregular at the end of the welding path assigned to this robot.

[0008] The present invention has been made in view of such points, and an object thereof is to provide a welding robot system for a steel pipe column that can perform stable welding between an upper steel pipe column and a lower steel pipe column even when a plurality of welding robots are used.

Means for Solving the Problems

[0009] In view of the above problems, a welding robot system according to the present invention includes a plurality of welding robots that weld an upper steel pipe column and a lower steel pipe column by supplying a molten welding material to a groove formed along the circumferential direction of the upper steel pipe column and the lower steel pipe column that are temporarily fixed by connecting erection pieces with erection jigs, and a control device that controls the operation of each welding robot and the execution and stop of welding by each welding robot so as to perform welding on a welding section set for each welding robot. The control device includes a section setting unit that sets the welding section for each welding robot, with the divided section obtained by dividing the groove that circumscribes along the circumferential direction according to the number of the welding robots, and a pair of overlapping sections that overlap with adjacent divided sections at both ends of the divided section, as the welding section; a welding start setting unit that sets the start of welding for each welding robot so that the overlapping section where each welding robot starts welding in the welding section for each welding robot is a different overlapping section from the overlapping section where other welding robots start welding; an interruption position setting unit that sets an interruption position where the welding is interrupted in the divided section for each welding robot; a welding execution unit that causes the welding robot to execute welding from one of the pair of overlapping sections until the other overlapping section, after starting welding from one of the pair of overlapping sections, interrupting the welding at the interruption position; and a welding start detection unit that detects the start of welding for each welding robot. The welding execution unit is characterized in that when the start of welding of any one of the plurality of welding robots has not been detected, after causing other welding robots to execute welding up to the interruption position, it continues to interrupt the welding of the other welding robots until the welding of the welding robot whose start has not been detected starts.

[0010] According to the present invention, a plurality of welding robots can weld an upper steel pipe column and a lower steel pipe column while supplying molten welding material to a groove formed along the circumferential direction of the upper steel pipe column and the lower steel pipe column in a welding section set for each welding robot by a section setting unit. Here, a overlapping section where each welding robot starts welding is a different overlapping section from an overlapping section where other welding robots start welding by a welding start setting unit. For this reason, since the welding robots do not start welding simultaneously for the same overlapping section, the welding robots do not come into contact with each other when starting welding by a plurality of welding robots.

[0011] In this way, the welding execution unit can start welding from one of a pair of overlapping sections, interrupt the welding at an interruption position, and cause the welding robot to execute welding up to the other overlapping section.

[0012] Here, when the start of welding of any one of the plurality of welding robots has not been detected, the welding execution unit causes other welding robots to execute welding up to the interruption position, and then continues to interrupt the welding of the other welding robots until the welding of the welding robot whose start has not been detected starts. In this way, when the welding of one welding robot is not started, the other welding robots are interrupted at the interruption position, so that it is possible to avoid the welding robots coming into contact with each other in the overlapping section. Furthermore, since the interruption of the welding robot continues at a position where it is instructed to interrupt welding from the beginning, the quality of the welding by the welding robot is not impaired. As a result, even when a plurality of welding robots are used, stable welding of the upper steel pipe column and the lower steel pipe column can be performed.

[0013] As a preferred embodiment, the control device is provided for each of the welding robots, and the control device of each welding robot outputs a welding start signal to the control device of the other welding robot by a start signal output unit from when the welding robot controlled by the control device starts the welding in the one overlapping section until the other welding robot resumes the welding at the interruption position.

[0014] According to this embodiment, from when the welding robot starts the welding in the one overlapping section until the other welding robot resumes the welding at the interruption position, the start signal output unit can output a welding start signal to the control device of the other welding robot. Thereby, since the control device of the other welding robot receives this welding start signal, when the other welding robot reaches the interruption position, it can smoothly resume the welding without continuing the interruption.

[0015] Furthermore, as a preferred embodiment, the welding execution unit executes the welding so as to reciprocate between the one overlapping section and the other overlapping section, and the welding execution unit starts the welding from the other overlapping section of each welding robot after all the welding robots complete the welding from the one overlapping section to the other overlapping section.

[0016] According to this embodiment, after the welding execution unit completes the forward welding from the one overlapping section to the other overlapping section, it can perform the return welding from the other overlapping section to the one overlapping section of each welding robot. Thereby, also in the return welding, since the welding robot performs the welding of different overlapping sections, it can avoid contact between the welding robots and perform stable welding as designed.

[0017] As a more preferable aspect, the overlapping section is the section where the election piece is arranged. The election piece hinders continuous welding by a welding robot, and continuous welding has to be interrupted in the section where the election piece is arranged. Therefore, by setting this section as the overlapping section, the number of positions where the welding that is disadvantageous in terms of quality becomes discontinuous can be minimized.

[0018] As an even more preferable aspect, the interruption position is within the section where the election piece is arranged. In the position within the section where the election piece is arranged among the welding sections, the welding by the welding robot is interrupted, the posture of the welding robot is changed, and the welding is restarted. Therefore, if this position is utilized, welding can be performed more smoothly.

[0019] As an even more preferable aspect, the plurality of welding robots are a pair of articulated robots, and the welding execution unit causes each welding robot to execute the welding while running the articulated robot along a pair of rails attached to the lower steel pipe column so as to sandwich the lower steel pipe column.

[0020] According to this aspect, in order to perform the welding between the upper steel pipe column and the lower steel pipe column while operating the articulated robot along the rail and running it, there is a possibility that the articulated robots may come into contact with each other. However, with the above-described control, welding can be performed while avoiding such contact. Further, since the welding between the upper steel pipe column and the lower steel pipe column can be performed while opposing the tips of the torches of the pair of articulated robots across the central axis of the steel pipe column, the heat during welding to the upper steel pipe column and the lower steel pipe column can be input in a substantially symmetric manner across the central axis of the steel pipe column. As a result, distortion of the central axis of the steel pipe column and the like can be suppressed.

Effect of the Invention

[0021] According to the present invention, even when a plurality of welding robots are used, stable-quality welding between the upper steel pipe column and the lower steel pipe column can be performed more easily.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0023] Hereinafter, a robot system for welding a steel pipe column according to an embodiment of the present invention will be described with reference to the drawings.

[0024] 1. Regarding the temporarily fixed steel pipe column 1 FIG. 1 is a side view of a steel pipe column before welding by a welding robot system according to an embodiment of the present invention. Here, the upper steel pipe column 10 and the lower steel pipe column 20 are made of a polygonal steel pipe formed by four flat portions and four curved portions, and erection pieces 11 and 21 are attached to each flat portion of the upper steel pipe column 10 and the lower steel pipe column 20. Note that the upper steel pipe column 10 and the lower steel pipe column 20 are not limited to the rectangular steel pipe columns shown in FIGS. 2 and 3, etc. For example, they may be polygonal steel pipe columns other than rectangles (specifically, polygonal steel pipes with four or more sides), or may be multi-sided box columns such as four-sided box columns. In this embodiment, erection pieces are provided for each flat portion, but for example, erection pieces may be provided only for two opposing flat portions out of the four flat portions, or a plurality of erection pieces may be provided for one flat portion.

[0025] The lower edge surface 13 of the upper steel pipe column 10 is a tapered surface inclined outward, and the upper edge surface 23 of the lower steel pipe column 20 is a flat surface formed so as to be orthogonal to the longitudinal direction of the lower steel pipe column 20. Thus, when the lower edge surface 13 of the upper steel pipe column 10 is disposed to face the upper edge surface 23 of the lower steel pipe column 20, a groove 30 along the circumferential direction of the upper steel pipe column 10 and the lower steel pipe column 20 can be formed between the upper steel pipe column 10 and the lower steel pipe column 20.

[0026] Furthermore, in the present embodiment, a backing plate (not shown) is attached to the inner wall surface of the lower steel pipe column 20 along the circumferential direction. The backing plate protrudes in the vertical direction (the longitudinal direction of the lower steel pipe column 20) from the upper edge surface 23 of the lower steel pipe column 20, and when the upper steel pipe column 10 is disposed on the lower steel pipe column 20, the protruding portion of the backing plate 31 is inserted into the upper steel pipe column 10.

[0027] With such a backing plate, the gap between the upper steel pipe column 10 and the lower steel pipe column 20 can be covered with the backing plate, so that it is possible to prevent the molten welding material from entering the inside of the steel pipe column 1 during welding. In the present embodiment, the backing plate is attached to the inner wall surface of the lower steel pipe column 20. However, for example, the backing plate may be attached to the inner wall surface of the upper steel pipe column 10 so as to protrude from the lower edge surface 13 of the upper steel pipe column 10.

[0028] As shown in FIG. 1, the upper steel pipe column 10 and the lower steel pipe column 20 are temporarily fixed. The upper steel pipe column 10 is disposed on the lower steel pipe column 20, and the protruding portion of the backing plate is inserted into the upper steel pipe column 10. For example, the upper end portion of the erection jig 3 is fastened to the erection piece 11 using bolts or the like, and the lower end portion thereof is fastened to the erection piece 21 using bolts or the like. Thereby, the erection pieces 11 and 21 of the upper steel pipe column 10 and the lower steel pipe column 20 are connected by the erection jig 3, and the upper steel pipe column 10 and the lower steel pipe column 20 can be temporarily fixed.

[0029] Here, although a detailed description of the structure of the fitting jig 3 is omitted, each fitting jig 3 is configured to be able to adjust the distance between the two erection pieces 11 and 21 arranged vertically. After or during welding, the fitting jig 3 is removed from the erection pieces 11 and 21, and after or during welding, the erection pieces 11 and 21 are cut from the upper steel pipe column 10 and the lower steel pipe column 20.

[0030] 2. Regarding the rail 73 and its mounting structure As shown in FIG. 2, in this embodiment, a pair of welding robots (articulated robots) 80 weld the upper steel pipe column 10 and the lower steel pipe column 20, and the articulated robot 80 travels on the rail 73. A pair of rails 73 are attached to the lower steel pipe column 20 so as to sandwich the lower steel pipe column 20.

[0031] Specifically, a pair of support pieces 78, 78 are welded to each of the two planar portions located on the opposite sides among the four planar portions of the lower steel pipe column 20. In this embodiment, the first support member 71 is fixed to the support pieces 78, 78 so as to sandwich the lower steel pipe column 20 with the first support member 71. The first support member 71 is a long member such as an H-shaped steel, and the welding robot 80 extends in a direction orthogonal to the rail 73 on which it travels.

[0032] Furthermore, in this embodiment, a pair of second support members 72 are fixed across the pair of first support members 71 so as to sandwich the lower steel pipe column 20. The second support member 72 is a long member, and since the rail 73 is attached to the second support member 72 along the longitudinal direction, a pair of rails 73, 73 can be attached to the lower steel pipe column 20 so as to sandwich the lower steel pipe column 20. In this embodiment, the rail 73 is attached to the lower steel pipe column 20 using the first support member 71 and the second support member 72. However, for example, if rigidity can be ensured, the rail 73 may be attached to the lower steel pipe column 20.

[0033] In this embodiment, the rail 73 is a linear guide rail, and a carriage (slider) 74 is attached to the rail 73. The carriage 74 is movable along the rail 73 by a motor (not shown). In this embodiment, the travel control of the carriage 74, the drive control of the articulated robot 80 described later, welding, etc. according to the welding conditions by the torch 92 attached to the tip of the articulated robot 80 are performed by the control device 40 described later.

[0034] 3. About the welding robot system 100 The welding robot system 100 includes a pair of articulated robots 80A and 80B, and control devices 40A and 40B for controlling them. The articulated robots 80A and 80B are devices that supply molten welding material to the groove 30 formed along the circumferential direction of the upper steel pipe column 10 and the lower steel pipe column 20, which are temporarily fixed by connecting the erection pieces 11 and 21 with the jig 3, and weld the upper steel pipe column 10 and the lower steel pipe column 20.

[0035] The control devices 40A and 40B are devices that control the operations of the respective articulated robots 80A and 80B and the execution and stop of welding by the respective articulated robots 80A and 80B so as to perform welding on the welding sections 1T and 2T set for each of the articulated robots 80A and 80B.

[0036] In this embodiment, the following welding is performed by two articulated robots 80A and 80B. For example, welding may be performed by three or more articulated robots. Further, in this embodiment, control devices 40A and 40B are provided for each of the articulated robots 80A and 80B, but the control of a plurality of articulated robots may be performed by one control device. First, the articulated robot 80 (80A, 80B) will be described in detail below.

[0037] 4. About the welding robot 80 (80A, 80B) The articulated robot 80 is installed on the carriage 74. The articulated robot 80 used in this embodiment is a robot arm that rotates on six axes and is a welding robot connected to a welding machine.

[0038] The multi-joint robot 80 is a welding robot connected to a welding machine (not shown) and a control device 40. The multi-joint robot 80 includes a base 82 attached to a carriage 74, and a swivel base 83 placed on the base 82 and swiveling with respect to the base 82. A lower arm 84 is pivotally attached to the swivel base 83. A joint portion 85 is pivotally attached to the tip of the lower arm 84. An upper arm 86 is rotatably attached to the joint portion 85 about the longitudinal direction as an axis.

[0039] The running of the carriage 74, the swiveling of the swivel base 83, the pivoting of the lower arm 84, and the rotation of the upper arm 86, etc. are respectively performed by actuators (not shown) such as motors. The control device 40 can control the operation of the multi-joint robot 80 by controlling these actuators.

[0040] Furthermore, a support arm 87 that supports a torch 92 of a welding machine serving as an end effector is attached to the tip of the upper arm 86. The support arm 87 is relative to the upper arm 86. A cable 91 for feeding a welding wire is connected to the torch 92, and the base end of the cable 91 is connected to a feeding device (not shown) for feeding the welding wire.

[0041] By applying the torch 92 of the welding machine, an arc is generated. When the welding wire is fed to this arc, the welding wire melts, and the melted welding material can be supplied to the groove 30. The control device 40 can control the execution and stop of welding by controlling the application and stop of the torch 92, and the feeding and stop of the welding wire.

[0042] 5. Regarding the control device 40 (40A, 40B) The control device 40 is connected to an articulated robot 80, a welding machine (not shown), and the like. The control device 40 includes a storage device (not shown) such as a RAM and a ROM in which programs for controlling these devices, welding conditions, etc. are recorded, and an arithmetic device (not shown) such as a CPU that calculates control commands for executing the control.

[0043] Figure 3 is a block diagram of the control device 40 of the articulated robot 80 shown in Figure 2. In the present embodiment, as shown in Figure 3, each control device 40A, 40B includes at least a section setting unit 41, a welding start setting unit 42, an interruption position setting unit 43, a welding execution unit 44, a welding start detection unit 46, and a start signal output unit 47 as software.

[0044] The section setting unit 41 sets a welding section for each articulated robot 80 with respect to the groove 30 formed along the circumferential direction of the temporarily fixed upper steel pipe column 10 and the lower steel pipe column 20 according to the number of articulated robots 80. In the present embodiment, since the number of articulated robots 80 is two, two welding sections 1T, 2T are set.

[0045] As shown in Figures 4 and 5, each welding section 1T, 2T is composed of divided sections 1D, 2D that divide the circumferential groove 30 (welding line), and a pair of overlapping sections 1S, 1E (2S, 2E) that overlap with the adjacent divided sections 1D (2D) at both ends of the divided sections 1D, 2D.

[0046] As shown in Figures 5(a) and (b), the overlapping sections 1S, 1E (2S, 2E) are sections where the erection pieces 11, 21 are arranged and are sections facing the built-in jig 3. The overlapping section 1S by the articulated robot 80A and the overlapping section 2E by the articulated robot 80B are the same section. The overlapping section 1E by the articulated robot 80A and the overlapping section 2S by the articulated robot 80B are the same section. In these overlapping sections 1S, 1E (2S, 2E), welding is performed at different timings by the two articulated robots 80A, 80B.

[0047] The welding start setting unit 42 sets the start of welding for each articulated robot 80 such that, in the welding section for each articulated robot 80, the overlapping section where each articulated robot 80 starts welding is a different overlapping section from the overlapping section where other articulated robots 80 start welding.

[0048] Specifically, in this embodiment, in the welding sections 1T and 2T for the articulated robots 80A and 80B respectively, the overlapping section where the articulated robot 80A starts welding is the overlapping section 1S, and the overlapping section where the articulated robot 80B starts welding is the overlapping section 2S, and these sections are different sections.

[0049] Therefore, in this embodiment, the articulated robot 80A starts welding in the overlapping section 1S and ends welding in the overlapping section 1E. Further, the articulated robot 80B starts welding in the overlapping section 2S and ends welding in the overlapping section 2E.

[0050] In this way, since the articulated robots 80A and 80B do not start welding simultaneously for the same overlapping section, the articulated robots 80A and 80B do not come into contact when starting welding by the plurality of articulated robots 80A and 80B.

[0051] Furthermore, the overlapping sections 1S, 1E (2S, 2E) are the sections where the erection pieces 11 and 21 are arranged, and are sections where it is difficult to perform continuous welding, and the welding becomes discontinuous. On the other hand, these overlapping sections 1S, 1E (2S, 2E) are at positions equidistant from the two rails 73, 73 and are the boundary positions of the welding ranges assumed by the two articulated robots 80A and 80B. Therefore, by setting the overlapping sections 1S, 1E (2S, 2E) as the sections where the erection pieces 11 and 21 are arranged, the number of locations of the welding discontinuity parts where defects are likely to occur in terms of quality can be minimized.

[0052] Furthermore, when welding is started smoothly, welding can be performed while avoiding contact between the articulated robots 80A and 80B. Further, in such a case, welding of the upper steel pipe column 10 and the lower steel pipe column 20 can be performed while opposing the tips of the torches 92 of the pair of articulated robots 80A and 80B across the central axis of the steel pipe column 1. Therefore, heat during welding to the upper steel pipe column 10 and the lower steel pipe column 20 can be input substantially symmetrically across the central axis of the steel pipe column 1. As a result, distortion and the like of the central axis of the steel pipe column 1 can be suppressed.

[0053] The interruption position setting unit 43 sets interruption positions 1P and 2P at which welding is interrupted in the divided sections 1D and 2D for each of the articulated robots 80A and 80B. For example, the interruption positions 1P and 2P are within the sections where the erection pieces 11 and 21 are arranged.

[0054] In this way, the welding section 1T (2T) is composed of a welding section 1R (2R) for performing the first half of the welding and a welding section 1L (2L) for performing the second half of the welding, with the interruption position 1P (2P) as a boundary. The welding section 1R (2R) and the welding section 1L (2L) may form overlapping sections before and after interruption of the welding by the articulated robot 80A (80B).

[0055] In the present embodiment, within the section of the welding section 1T (2T) where the erection pieces 11 and 21 are arranged, welding by the articulated robot 80A (80B) is interrupted in the first place, the posture of the articulated robot 80A (80B) is changed, and welding is resumed. Therefore, by using this position, welding by the articulated robot 80A (80B) can be performed more smoothly.

[0056] Note that the settings by the section setting unit 41, the welding start setting unit 42, and the interruption position setting unit 43 are input to the control devices 40A and 40B via an input device (not shown).

[0057] The welding execution unit 44 controls the articulated robot 80A (80B) to start welding from one of the pair of overlapping sections 1S, 1E (2S, 2E) and interrupt the welding at the interruption position 1P (2P). Further, after changing the posture of the articulated robot 80A (80B), the welding execution unit 44 causes the articulated robot 80A (80B) to perform welding between the upper steel pipe column 10 and the lower steel pipe column 20 up to the other overlapping section 1E (2E).

[0058] Here, the welding start detection unit 46 may detect the start of welding of the articulated robot 80A (80B) in one of the overlapping sections 1S (2S). However, in this embodiment, it is preferable that the welding start detection unit 46 detects the start of welding after finishing (completing) the welding of the overlapping section 1S (2S) and starting the welding of the divided sections 1D, 2D. Thereby, since the start of welding is detected after passing through the overlapping section 1S (2S) where welding is likely to stop (the generated arc is difficult to stabilize), the reliability of detection can be improved. Further, the welding start detection unit 46 also detects the resumption of welding for each articulated robot 80A, 80B from the interruption positions 1P, 2P. In this embodiment, the welding start detection unit 46 of the control devices 40A, 40B detects the welding start signal and the welding resumption signal of one of the articulated robots 80A. Similarly, the welding start detection unit 46 of the control devices 40A, 40B detects the welding start signal and the welding resumption signal of the other articulated robot 80B. In this embodiment, as will be described later, the articulated robots 80A, 80B continuously output the welding start signal and the welding resumption signal. However, at the timing of welding start and welding resumption, the welding start signal is output, and at the timing of welding completion, the welding end signal is output. Based on these signals, the control devices 40A, 40B may control the articulated robots 80A, 80B.

[0059] Further, when the start of welding of any one of the plurality of articulated robots 80 is not detected, the welding execution unit 44 causes another articulated robot 80 to perform welding up to the interruption position, and then continues to interrupt the welding of the other articulated robot 80 until the welding of the articulated robot 80 for which the start has not been detected is started.

[0060] Specifically, in this embodiment, the plurality of articulated robots 80 are composed of two articulated robots 80A and 80B. Therefore, for example, when the start of welding of one articulated robot 80A is not detected due to poor arc generation or the like, the welding execution unit 44 of the other control device 40B causes the articulated robot 80B to execute welding of the welding section 2R up to the interruption position 2P. Thereafter, until the welding of one articulated robot 80A is started (that is, until the welding start detection unit 46 of the other control device 40A detects the start of welding of the articulated robot 80A), the interruption of welding of the other articulated robot 80 is continued. When the welding of one articulated robot 80A is started, the welding execution unit 44 causes the other articulated robot 80B to execute welding of the welding section 2L.

[0061] Similarly, when the start of welding of the other articulated robot 80B is not detected, the welding execution unit 44 of one control device 40A causes the articulated robot 80A to execute welding of the welding section 1R up to the interruption position 1P. Thereafter, until the welding of the other articulated robot 80B is started, the interruption of welding of one articulated robot 80 is continued. When the welding of the other articulated robot 80 is started, the welding execution unit 44 causes one articulated robot 80A to execute welding of the welding section 1L.

[0062] In this way, when the welding of one articulated robot 80A (80B) is not started, the other articulated robot 80B (80A) is interrupted at the interruption position 2P (1P), so that the articulated robots 80B and 80A can be prevented from contacting in the overlapping sections 2E, 1S (1E, 2S). Furthermore, since the interruption of one articulated robot 80A (80B) continues at the position where the welding is initially interrupted, the quality of welding by one articulated robot 80A (80B) is not impaired. As a result, even when a pair of articulated robots 80B and 80A are used, stable welding between the upper steel pipe column 10 and the lower steel pipe column 20 can be performed.

[0063] The start signal output unit 47 outputs a welding start signal to the control device 40B (40A) of the other articulated robot 80B (80A) from when the welding of one of the overlapping sections 1S (2S) by one of the articulated robots 80A (80B) is completed and the welding of the divided sections 1D, 2D is started until the other articulated robot 80B (80A) resumes welding at the interruption position 2P (1P). Here, the start of welding by one of the articulated robots 80A (80B) and the resumption of welding at the interruption position 2P (1P) are detected by the welding start detection unit 46.

[0064] As a result, since the control device 40B (40A) of the other articulated robot 80B (80A) receives this welding start signal, when the other articulated robot 80B (80A) reaches the interruption position 2P (1P), it can smoothly resume welding without the interruption continuing.

[0065] Furthermore, the welding execution unit 44 causes the articulated robot 80B (80A) to execute welding so as to reciprocate between one overlapping section 1S (2S) and the other overlapping section 1E (2E). After all the articulated robots 80B, 80A have completed welding from one overlapping section 1S (2S) to the other overlapping section 1E (2E), the welding execution unit 44 starts the welding from the other overlapping section 1E (2E) of the articulated robot 80A (80B). Thereby, even in the return path welding, stable welding as designed can be performed while avoiding contact between the articulated robots 80A, 80B.

[0066] Hereinafter, with reference to FIG. 6, the control flowchart of the control device 40 shown in FIG. 3 will be described. First, in step S1, the welding execution unit 44 starts welding of the articulated robots 80A, 80B from one of the overlapping sections 1S, 2S. Next, in step S2, when the welding start detection unit 46 detects the start of welding, the start signal output unit 47 continuously outputs a welding start signal.

[0067] Next, proceed to step S3. When one of the articulated robots 80A (80B) reaches the interruption position 1P (2P), the welding execution unit 44 interrupts the welding of the reached articulated robot 80A (80B) and proceeds to step S4.

[0068] In step S4, it is determined whether the other articulated robot 80B (80A) has started welding in one of the overlapping sections 1S (2S). Specifically, the other control device 40B (40A) determines whether the start signal output unit 47 has output a welding start signal. Here, when welding has not started (in the case of NO), step S4 is repeated. As a result, the interruption of welding by one of the articulated robots 80A (80B) continues. On the other hand, when welding has started, proceed to step S5.

[0069] In step S5, the welding execution unit 44 changes the posture of one of the articulated robots 80A (80B) and resumes welding in the remaining welding section 1L (2L). In step S6, at the timing when one of the articulated robots 80A (80B) resumes welding, the start signal output unit 47 continuously outputs a welding resume signal. At this time, the start signal output unit 47 has been continuously outputting the welding start signal since step S2. Note that in step S3, the welding of one of the articulated robots 80A (80B) was interrupted, and in step S5, the posture of one of the articulated robots 80A (80B) was changed. However, after changing the posture of one of the articulated robots 80A (80B) in step S3, it may be possible to proceed to step S4. In this case, in step S5, the welding of one of the articulated robots 80A (80B) can be resumed promptly.

[0070] In step S7, the welding execution unit 44 causes one of the articulated robots 80A (80B) to finish welding in the other overlapping section 1E (2E). At this time, the operation of the articulated robot 80A (80B) is also stopped.

[0071] In step S8, one of the control devices 40A (40B) determines whether the multi-joint robot 80B (80A) has resumed welding from the interruption position 2P (1P). Specifically, the start signal output unit 47 of the other control device 40B (40A) determines whether the welding resume signal is continuously being output. Here, if welding has not resumed (in the case of NO), step S8 is repeated.

[0072] On the other hand, if welding has resumed (in the case of YES), the process proceeds to step S9. In step S9, since the welding start signal of one of the multi-joint robots 80A (80B) is no longer necessary, this output is terminated, and the process proceeds to step S10. In step S10, since the welding start signal of the other multi-joint robot 80B (80A) is no longer necessary, this output is terminated, and the process proceeds to step S11.

[0073] In step S11, since one of the multi-joint robots 80A (80B) has reached the other overlapping section 1E (2E), the output of the welding resume signal is terminated, and the process proceeds to step S12. After the other multi-joint robot 80B (80A) has reached the other overlapping section 2E (1E), the output of the welding resume signal of the other multi-joint robot 80B (80A) is terminated.

[0074] In this way, it can be considered that all the multi-joint robots 80A and 80B have completed the welding from one overlapping section 1S (2S) to the other overlapping section 1E (2E), and the welding from the other overlapping section 1E (2E) to one overlapping section 1S (2S) is performed in the same manner as shown in steps S1 to S12. In this way, the welding for the forward path from one overlapping section 1S (2S) to the other overlapping section 1E (2E) and the welding for the return path from one overlapping section 1S (2S) to the other overlapping section 1E (2E) are repeated.

[0075] In this way, even when using a pair of multi-joint robots 80A and 80B, it is possible to avoid their contact and perform stable welding between the upper steel pipe column 10 and the lower steel pipe column 20.

[0076] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various design changes can be made without departing from the spirit of the present invention described in the claims.

Explanation of Reference Numerals

[0077] 1: Steel pipe column, 3: Erection jig, 10: Upper steel pipe column, 11: Erection piece, 20: Lower steel pipe column, 21: Erection piece, 30: Groove, 40, 40A, 40B: Control device, 41: Section setting unit, 42: Welding start setting unit, 43: Interruption position setting unit, 44: Welding execution unit, 46: Welding start detection unit, 47: Start signal output unit, 80, 80A, 80B: Welding robot (multi-joint robot), 100: Welding robot system, 1T, 2T: Welding section, 1D, 2D: Division section, 1S, 2S: Overlap section (one overlap section), 1E, 2E: Overlap section (the other overlap section), 1P, 2P: Interruption position

Claims

1. A plurality of welding robots that weld the upper steel pipe column and the lower steel pipe column while supplying molten welding material to a groove formed along the circumferential direction of the upper steel pipe column and the lower steel pipe column in which the erection piece is connected and temporarily fixed with a plumbing jig; a control device that controls an operation of each of the welding robots and the start and stop of welding by each of the welding robots so that welding is performed in a welding section set for each of the welding robots; A welding robot system comprising at least The control device includes: A section setting unit that sets the welding sections for each of the welding robots, the welding sections being divided into divided sections that rotate along the circumferential direction and a pair of overlapping sections that overlap adjacent divided sections at both ends of the divided sections, depending on the number of the welding robots; a welding start setting unit that sets a start of welding for each welding robot so that the overlapping section in which each welding robot starts welding is different from an overlapping section in which another welding robot starts welding in the welding section for each welding robot; an interruption position setting unit that sets an interruption position where the welding is interrupted in the divided section for each of the welding robots; a welding execution unit that starts welding from one of the pair of overlapping sections, interrupts the welding at the interruption position, and causes the welding robot to perform the welding up to the other overlapping section; a welding start detection unit that detects the start of the welding for each welding robot, a welding robot system including: a welding execution unit that, when the start of welding by any one of the plurality of welding robots has not been detected, causes the other welding robot to perform welding up to the interruption position, and then continues to interrupt the welding by the other welding robot until the welding robot whose start has not been detected starts welding.

2. The control device is provided for each of the welding robots, 2. The welding robot system according to claim 1, wherein the control device of each of the welding robots further includes a start signal output unit that outputs a welding start signal to the control device of the other welding robot from the time when the welding robot controlled by the control device starts the welding in the overlapping section until the other welding robot resumes the welding at the interruption position.

3. the welding execution unit performs the welding so as to reciprocate between the one overlapping section and the other overlapping section, 3. The welding robot system according to claim 1, wherein the welding execution unit starts welding from the other overlapping section of each of the welding robots after all of the welding robots have completed welding from the one overlapping section to the other overlapping section.

4. The welding robot system according to any one of claims 1 to 3, characterized in that the overlapping section is a section in which the erection piece is arranged.

5. The welding robot system according to any one of claims 1 to 4, wherein the interruption position is within a section in which the erection piece is arranged.

6. The plurality of welding robots are a pair of articulated robots, The welding robot system according to any one of claims 1 to 5, characterized in that the welding execution unit causes each of the welding robots to perform the welding while running the articulated robot along a pair of rails attached to the lower steel pipe column so as to sandwich the lower steel pipe column.

Images