Portable type welding robot control method, welding control method, portable type welding robot and welding system

Abstract

To provide a portable type welding robot control method that can secure an excellent bead appearance, even if a corner part of a work-piece and a curve part of a guide rail do not exist on a concentric circle and a difference in curvature between the corner part of the work-piece and the curve part of the guide rail is large.SOLUTION: A portable type welding system comprises a portable type welding robot 100 that installs a guide rail on a work-piece Wo having a corner part and moves on the guide rail to arc-weld the work-piece Wo, and a welding control device 600 that controls the portable type welding robot 100. The portable type welding robot 100 comprises a welding torch 200 and a movable part that moves the welding torch 200 in a welding line direction. A portable type welding robot control method comprises: a step in which a torch position determining part 605 determines a torch position on the work-piece Wo; a step in which a torch angle calculating part 606 calculates a torch angle at the torch position; and a step in which the movable part controls the torch angle on the basis of the calculated torch angle.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control method for a portable welding robot capable of automatically performing welding while moving on a guide rail, a welding control device, a portable welding robot, and a welding system. [Background technology]

[0002] Conventionally, in the manufacture of welded structures in shipbuilding, steel frames, bridges, etc., the automation of welding work in factories has progressed, and large multi-axis welding robots are widely used. On the other hand, even in on-site welding work where large multi-axis welding robots cannot be applied, automation is being promoted from manual welding such as semi-automatic welding to welding methods using lightweight and small portable welding robots that can be carried by a single worker. The application of such portable welding robots can improve welding efficiency at welding sites where welding has been carried out manually up to now.

[0003] For example, Patent Document 1 is an example of a technology that applies this portable welding robot. In Patent Document 1, a guide rail using a corner unit having a straight portion and a curved portion is attached to the outer periphery of a polygonal square steel pipe to be welded, which is used in construction sites. A welding robot is then provided so as to be slidable relative to the guide rail. When the position of the center of curvature of the welded portion to be welded by the welding robot differs from the position of the center of curvature of the position where the welding robot is located in the corner unit when welding the welded portion, the control unit controls the moving speed of the welding robot so that the length of the welded portion per unit time by the welding robot (hereinafter also referred to as "bead length") is constant. This allows efficient welding of square steel pipes of various shapes. The bead length per unit time by the welding robot is also referred to as "welding speed". [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-58078 A Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, in Patent Document 1, the moving speed of the welding robot (hereinafter also referred to as "robot speed") is controlled, and efficient welding is possible by changing the welding speed to match the deposition amount even when the corner of the workpiece and the curved portion of the guide rail (hereinafter also referred to as "rail") are not concentric. However, the technology in Patent Document 1 only considers the control of the robot speed, and does not consider the effect of the torch angle, which becomes a problem when the corner of the workpiece and the curved portion of the rail are not concentric. In other words, the following phenomenon occurs. (1) When the robot is located on a curved portion of the rail and the tip of the torch is located on a parallel portion of the workpiece, the torch angle on the parallel portion of the workpiece is a forward angle or a backward angle. (2) When the robot is on a curved portion of the rail and the tip of the torch is on a corner of the workpiece, the torch angle at the corner of the workpiece is a forward angle or a backward angle.

[0006] If the torch angle becomes a forward or backward angle, for example, the following problems may occur. (In the case of forward angle) This makes it easier for spatters to form in the forward direction, leading to deterioration of welding workability. (In the case of a retreating angle) This pushes up the molten pool at the rear, resulting in the formation of a convex bead near the boundary between the corner and straight section on the workpiece, causing poor bead appearance. Furthermore, as the curvature of the corner of the workpiece becomes smaller and the difference in curvature with that of the rail becomes larger, the change in the torch angle becomes greater, and the bead appearance at the boundary between the straight section and the corner becomes even worse.

[0007] Here, for example, examples of workpieces with different radii of curvature include roll-formed polygonal rectangular steel pipes for building construction (BCP) and roll-formed polygonal rectangular steel pipes for building construction (BCR). Generally, the radius of curvature of BCP is calculated as 3.5t for the plate thickness t, but the radius of curvature of BCR is 2.5t. In other words, for BCP and BCR with the same plate thickness, if the radius of curvature of the rail is constant, the difference between the radius of curvature of the workpiece and the rail is larger for BCR. Therefore, the change in the torch angle at the curved part of the rail relative to the workpiece is larger for BCR, and it is characterized by the tendency for bead appearance defects to occur at the boundary between the straight part and the corner part.

[0008] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a control method for a portable welding robot, a welding control device, a portable welding robot, and a welding system that can ensure a good bead appearance even when the corner of the workpiece and the curved portion of the rail are not concentric and there is a large difference in curvature between the corner of the workpiece and the curved portion of the rail. [Means for solving the problem]

[0009] Therefore, the above object of the present invention can be achieved by the following configuration (A) relating to a control method for a portable welding robot.

[0010] (A) A method for controlling a portable welding robot using a welding system including a guide rail for a workpiece having a corner, a portable welding robot that moves on the guide rail to arc-weld the workpiece, and a welding control device that controls the portable welding robot, The portable welding robot has a welding torch and a movable part that moves the welding torch in a weld line direction, The welding control device has a torch position determination unit that determines a torch position on the workpiece, and a torch angle calculation unit that calculates a torch angle at the torch position, determining a torch position on the workpiece by the torch position determination unit; Calculating a torch angle at the torch position by the torch angle calculation unit; controlling the torch angle by the movable part based on the calculated torch angle; A method for controlling a portable welding robot comprising the steps of:

[0011] The above object of the present invention can be achieved by the following configuration (B) relating to a welding control device.

[0012] (B) A welding control device for controlling a portable welding robot that installs a guide rail for a workpiece having a corner and moves on the guide rail to arc-weld the workpiece, A torch position determination unit that determines a torch position on the workpiece, and a torch angle calculation unit that calculates a torch angle at the torch position, The torch position determination unit determines a torch position on the workpiece, The torch angle calculation unit calculates a torch angle at the torch position, A welding control device characterized in that the torch angle is controlled based on the calculated torch angle.

[0013] The above object of the present invention can be achieved by the following configuration (C) relating to a portable welding robot.

[0014] (C) A portable welding robot that is controlled by the welding control device described above, which has a guide rail installed for a workpiece having a corner, moves on the guide rail, and arc-welds the workpiece, A welding torch and a movable part that moves the welding torch in a welding line direction, The portable welding robot is characterized in that the movable part controls the torch angle based on the torch angle calculated by the torch angle calculation part.

[0015] The above object of the present invention can be achieved by the following configuration (D) of a welding system.

[0016] (D) A welding system including a portable welding robot that installs a guide rail for a workpiece having a corner and moves on the guide rail to arc-weld the workpiece, and a welding control device that controls the portable welding robot, The portable welding robot has a welding torch and a movable part that moves the welding torch in a weld line direction, The welding control device has a torch position determination unit that determines a torch position on the workpiece, and a torch angle calculation unit that calculates a torch angle at the torch position, The torch position determination unit determines a torch position on the workpiece, The torch angle calculation unit calculates a torch angle at the torch position, A welding system comprising: a movable part that controls the torch angle based on the calculated torch angle.

[0017] The above object of the present invention can be achieved by the following configuration (E) relating to a method for controlling a portable welding robot.

[0018] (E) A method for controlling a portable welding robot using a welding system including a guide rail for a polygonal square steel pipe, a portable welding robot that moves on the guide rail to arc-weld the polygonal square steel pipe, and a welding control device that controls the portable welding robot, The portable welding robot has a welding torch and a movable part that moves the welding torch in a weld line direction, The welding control device has a torch position determination unit that determines a torch position on the polygonal square steel pipe, and a torch angle calculation unit that calculates a torch angle at the torch position, A step of determining a torch position on the polygonal square steel pipe by the torch position determination unit; Calculating a torch angle at the torch position by the torch angle calculation unit; controlling the torch angle by the movable part based on the calculated torch angle; A method for controlling a portable welding robot comprising the steps of: Effect of the Invention

[0019] According to the control method for a portable welding robot of the present invention, even when the corner of the workpiece and the curved portion of the guide rail are not on concentric circles and there is a large difference in curvature between the corner of the workpiece and the curved portion of the guide rail, the torch angle can be controlled according to torch position information on the workpiece, thereby improving the bead appearance at the corner of the workpiece and at the boundary between the corner and the straight portion. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram of one embodiment of a welding system according to the present invention. [Diagram 2] FIG. 2 is a schematic side view of the portable welding robot shown in FIG. [Diagram 3] FIG. 3 is a perspective view of the portable welding robot shown in FIG. [Figure 4] FIG. 4 is a perspective view of the welding robot shown in FIG. 3 attached to a polygonal square steel pipe. [Diagram 5] FIG. 5 is a diagram for explaining the positional relationship with the guide rail in the region of the 1 / 4 corner of the polygonal square steel pipe when viewed from directly above in FIG. [Figure 6] FIG. 6 is a diagram of FIG. [Figure 7] FIG. 7 is a graph showing the relationship between the angle θ of the straight line connecting the center of curvature of the guide rail and the portable welding robot on the guide rail, and the torch angle correction amount θT. [Figure 8] FIG. 8 is a graph showing the relationship between the moving distance D of the portable welding robot and the torch angle correction amount θT. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, a welding system according to an embodiment of the present invention will be described with reference to the drawings. Note that this embodiment is an example of a case in which a portable welding robot is used, and the welding system of the present invention is not limited to the configuration of this embodiment.

[0022] <Welding system configuration> Fig. 1 is a schematic diagram showing the configuration of a welding system according to the present embodiment. As shown in Fig. 1, a welding system 50 includes a portable welding robot 100, a feeder 300, a welding power source 400, a shielding gas supply source 500, and a control device 600.

[0023] [Control device] The control device 600 is connected to the portable welding robot 100 by a robot control cable 620 and is connected to the welding power source 400 by a power source control cable 630 .

[0024] The control device 600 previously stores information on the workpiece, the guide rail, and the workpiece W. o and data storage unit 601 that stores teaching data that defines the position information of guide rail 120, the operation pattern of portable welding robot 100, the welding start position, the welding end position, the welding conditions, the weaving operation, etc. Based on this teaching data, commands are sent to portable welding robot 100 and welding power source 400 to control the operation of portable welding robot 100 and the welding conditions.

[0025] The control device 600 also includes a groove condition calculation unit 602 that calculates groove shape information from detection data obtained by sensing such as touch sensing or a visual sensor, and a welding condition calculation unit 603 that corrects the welding conditions of the teaching data based on the groove shape information to acquire the welding conditions. In addition, the portable welding robot 100 includes a speed control unit 604 that controls a drive unit (not shown) for driving in the X direction, Y direction, and Z direction described later, a torch position determination unit 605 that determines the torch position, and a torch angle calculation unit 606 that controls a torch angle drive unit (movable arm unit 116) in the portable welding robot 100. A control unit 610 is configured including the groove condition calculation unit 602, the welding condition calculation unit 603, the speed control unit 604, the torch position determination unit 605, and the torch angle calculation unit 606. The torch position determination unit 605 and the torch angle calculation unit 606 can also be configured as one.

[0026] Furthermore, the control device 600 is formed by integrating a controller for teaching and a controller having other control functions. However, the control device 600 is not limited to this, and may be divided into multiple parts according to the role, such as dividing the controller for teaching and the controller having other control functions into two. Also, the control device 600 may be included in the portable welding robot 100, or may be provided separately from the portable welding robot 100 as shown in FIG. 1. That is, in the welding system having the portable welding robot 100 and the control device 600 described in this embodiment, both the case where the control device 600 is included in the portable welding robot 100 and the case where the control device 600 is provided independently of the portable welding robot 100 are included. Also, in this embodiment, the signals are sent using the robot control cable 620 and the power supply control cable 630, but this is not limited to this, and the signals may be sent wirelessly. From the viewpoint of usability at the welding site, it is preferable to divide the controller into two, a controller for teaching and a controller having other control functions.

[0027] [Welding power source] The welding power source 400, in response to a command from the control device 600, supplies a consumable electrode (hereinafter also referred to as "welding wire") 211 and a workpiece W o By supplying power to the welding wire 211 and the workpiece W o An arc is generated between the welding power source 400 and the welding wire 211. Power from the welding power source 400 is sent to the wire feeder 300 via a power cable 410, and is then sent to the welding torch 200 from the wire feeder 300 via a conduit tube 420. Then, as shown in FIG. 2, the power is supplied to the welding wire 211 via a contact tip at the front end of the welding torch 200. The current during the welding operation may be either DC or AC, and the waveform is not particularly important. Therefore, the current may be a pulse such as a square wave or a triangular wave.

[0028] In addition, the welding power source 400 is, for example, connected to the welding torch 200 side with the power cable 410 as a positive (+) electrode and connected to the workpiece W with the power cable 430 as a negative (-) electrode. o This is the case when welding with reverse polarity. When welding with positive polarity, the work W is connected to the positive (+) power cable. o side and connected to the welding torch 200 side via a negative (-) power cable.

[0029] [Shielding gas supply source] The shielding gas supply source 500 is composed of a container filled with shielding gas and auxiliary members such as a valve. The shielding gas is sent from the shielding gas supply source 500 to the feeder 300 via a gas tube 510. The shielding gas sent to the feeder 300 is sent to the welding torch 200 via a conduit tube 420. The shielding gas sent to the welding torch 200 flows inside the welding torch 200, is guided by the nozzle 210, and is ejected from the tip side of the welding torch 200. The shielding gas used in this embodiment may be, for example, argon (Ar), carbon dioxide (CO2), or a mixture thereof.

[0030] [Feeding device] The feeder 300 pays out the welding wire 211 and feeds it to the welding torch 200. The welding wire 211 fed by the feeder 300 is not particularly limited, and may be fed to the workpiece W. o The material of the welding wire 211 is selected depending on the properties of the wire and the welding form, and for example, a solid wire or a flux-cored wire (hereinafter also referred to as "FCW") is used. The material of the welding wire 211 is not particularly limited, and may be, for example, mild steel, stainless steel, aluminum, titanium, or other materials. The wire diameter of the welding wire 211 is also not particularly limited, but in this embodiment, the preferred wire diameter is 1.6 mm at the upper limit and 0.9 mm at the lower limit.

[0031] Conduit tube 420 according to this embodiment has a conductive path formed on the outer skin side of the tube to function as a power cable, and a protective tube for protecting welding wire 211 is disposed inside the tube, and a flow path for shielding gas is formed. However, conduit tube 420 is not limited to this, and for example, a power supply cable and a hose for supplying shielding gas may be bundled around a protective tube for feeding welding wire 211 to welding torch 200. Also, for example, a tube for feeding welding wire 211 and shielding gas and a power cable may be installed separately.

[0032] [Portable welding robot] 2 and 3, the portable welding robot 100 includes a guide rail 120, a robot body 110 that is installed on the guide rail 120 and moves along the guide rail 120, and a torch connection part 130 that is placed on the robot body 110. The robot body 110 is mainly composed of a housing part 112 that is installed on the guide rail 120, a fixed arm part 114 that is attached to the housing part 112, and a movable arm part 116 that is attached to the fixed arm part 114 in a state that it can rotate in the direction of arrow R1.

[0033] Torch connection part 130 is attached to movable arm part 116 via crank 170, which is a movable part that moves welding torch 200 in the weld line direction, i.e., in the X direction. Torch connection part 130 includes torch clamp 132 and torch clamp 134 that fix welding torch 200. Furthermore, housing part 112 is provided with cable clamp 150 that supports conduit tube 420 that connects feeding device 300 and welding torch 200 on the side opposite to the side on which welding torch 200 is attached.

[0034] In this embodiment, the work W o A voltage is applied between the workpiece W and the welding wire 211, and the welding wire 211 is o By utilizing the voltage drop phenomenon that occurs when the workpiece W o The detection means is a touch sensor that senses the surface of the upper groove 10. The detection means is not limited to the touch sensor of this embodiment, and an image sensor, i.e., visual sensing, or a laser sensor, i.e., laser sensing, or a combination of these detection means may be used, but it is preferable to use the touch sensor of this embodiment from the perspective of simplicity of the device configuration.

[0035] 2, the housing 112 of the robot body 110 includes a robot drive unit (not shown) that drives in a direction perpendicular to the paper surface, i.e., in the X direction in which the robot body 110 moves along the guide rail 120. The housing 112 can also be driven in the Z direction in which it moves in the depth direction of the groove 10 perpendicular to the X direction. The fixed arm 114 can also be driven in the Y direction, which is the width direction of the groove 10 perpendicular to the X direction, relative to the housing 112 via the slide support 113.

[0036] Furthermore, the torch connection part 130 to which the welding torch 200 is attached can be driven to swing back and forth in the X direction, i.e., in the direction of the weld line, by rotating the crank 170 as shown by the arrow R2 in Fig. 3. Also, the movable arm part 116 is attached rotatably to the fixed arm part 114 as shown by the arrow R1, and can be adjusted to an optimal angle and fixed.

[0037] As described above, the robot body 110 can drive the welding torch 200, which is the tip of the robot body 110, with three degrees of freedom. However, the robot body 110 is not limited to this, and may be capable of driving with any number of degrees of freedom depending on the application.

[0038] With the above-mentioned configuration, the tip of the welding torch 200 attached to the torch connecting part 130 can be directed in any direction. Furthermore, the robot body 110 can be driven on the guide rail 120 in the X direction in FIG. 2. The welding torch 200 can perform weaving welding by moving the robot body 110 in the X direction while reciprocating in the Y direction. Furthermore, by driving the crank 170, the welding torch 200 can be tilted depending on the construction situation, for example, by providing a forward angle or a backward angle. Furthermore, by tilting the welding torch 200 in the X direction by driving the crank 170, the workpiece W such as a polygonal square steel pipe described later can be weaved. o This makes it possible to correct a change in the torch angle, i.e., the forward or backward angle, that occurs when the curvature of the corner WC of the guide rail 120 differs from that of the curved portion 122 of the guide rail 120.

[0039] A mounting member 140 such as a magnet is provided below the guide rail 120. The guide rail 120 is supported by the mounting member 140 so as to mount the workpiece W. o The portable welding robot 100 is configured to be easily attached to and detached from the work W. o When the portable welding robot 100 is set on the workpiece W, the operator holds the handles 160 on both sides of the portable welding robot 100 to move the portable welding robot 100 to the workpiece W. o It can be easily set on top.

[0040] <Torch angle control method> Next, a specific example of a method for controlling the torch angle when welding a polygonal square steel pipe by a portable welding robot traveling on a guide rail will be described. Fig. 4 is a perspective view of the portable welding robot 100 shown in Fig. 3 attached to a polygonal square steel pipe. As shown in Fig. 4, the guide rail 120 supports the work W. o The portable welding robot 100 is attached to the outer surface of a polygonal square steel pipe along the circumferential direction. In this case, the guide rail 120 is provided so as to go around the outer surface of the steel pipe via the attachment member 140, and has a shape having a straight portion 121 and a curved portion 122. The portable welding robot 100 is attached on the guide rail 120 with the welding torch 200 facing downward. Figure 5 shows the polygonal rectangular steel pipe W when viewed from directly above Figure 4. o 13 is a diagram for explaining the positional relationship with the guide rail 120 in the quarter corner area of ​​the roller bearing 100. FIG.

[0041] 4 and 5, the guide rail 120 has a straight portion 121, a curved portion 122, and a boundary point 128 where the guide route changes between the straight portion 121 and the curved portion 122. o has a straight line portion WL, a corner portion (curve portion) WC, and a boundary point WB between the straight line portion WL and the corner portion WC.

[0042] In this example, the radius of curvature RA of the curved portion 122 of the guide rail 120 is o The curvature radius RB of the corner WC is larger than that of the polygonal rectangular steel pipe W o The corner portion WC and the curved portion 122 of the guide rail 120 are not concentric. o The radius of curvature RB of the corner WC in differs between the outer periphery and the inner periphery, but since it is sufficient that the total amount of deposition is the same, in this specific example, it is set to the average value of the outer periphery and the inner periphery.

[0043] As shown in FIG. 5, the radius of curvature RA of the curved portion 122 of the guide rail 120 is determined by the center of curvature O Aand the rail center R of guide rail 120 c The distance between the polygonal square steel pipe W and o The radius of curvature RB of the corner WC at the center of curvature O of the corner WC is B and polygonal rectangular steel pipe W o Plate thickness center W c The distance is set to be .

[0044] The radius of curvature RA of the curved portion 122 of the guide rail 120 and the polygonal square steel pipe W o The curvature radius RB of the corners WC of the polygonal square steel pipe W is different (in this example, RA>RB) and is not on a concentric circle. o In the welding area, the portable welding robot 100 is located on the straight portion 121 of the guide rail 120, and the welding torch 200 is positioned on the polygonal square steel pipe W. o The first area I is located in the straight section WL of the guide rail 120, and the portable welding robot 100 is located in the curved section 122 of the guide rail 120 and the welding torch 200 is positioned on the polygonal rectangular steel pipe W. o A second area II is located in the straight section WL of the guide rail 120, and a portable welding robot 100 is located in the curved section 122 of the guide rail 120 and a welding torch 200 is located in the polygonal rectangular steel pipe W. o and a third region III located at the corner WC.

[0045] The portable welding robot 100 moves along the guide rail 120 based on the operation signal of the control device 600 and welds the polygonal square steel pipe W. o The guide rail 120 has a straight section 121, a curved section 122, and a boundary point 128, and in order to maintain a substantially constant welding quality over the entire length of the weld, it is preferable that the torch angle of the welding torch 200 is substantially constant regardless of the position on the guide rail 120 of the portable welding robot 100. Examples of the position on the guide rail 120 include the straight section 121, the curved section 122, and the boundary point 128. The torch angle in the first region I is set to 1 / 2.0°. o In the second region II and the third region III, the welding torch 200 is perpendicular to the polygonal rectangular steel pipe W. oThere are cases where the torch angle is not perpendicular to the polygonal rectangular steel pipe W in the first region I. o It is preferable to control the torch angle to a substantially constant value based on the torch angle at the straight portion WL.

[0046] Here, a substantially constant torch angle means that an angle error is allowed within a practically controllable angle range and does not affect welding quality. Specifically, in this embodiment, the angle error is preferably within ±10°, more preferably within ±5°, and most preferably substantially 0°.

[0047] Specifically, in FIG. 5, the polygonal rectangular steel pipe W o For example, when the welding torch 200 is at a right angle to the straight section WL of the polygonal square steel pipe W, that is, when the torch angle is 0°, the portable welding robot 100 moves counterclockwise from the lower right to the upper side on the straight section 121 of the guide rail 120. o Before reaching the corner WC, the roller 110 reaches the curved portion 122 on the guide rail 120 and exits the first region I.

[0048] That is, the welding torch 200 of the portable welding robot 100 is o When the robot body 110 enters the second region II located in the curved portion 122 of the guide rail 120, the welding torch 200 tilts and the torch angle becomes more forward or backward, thereby changing the torch angle. Since the change in the torch angle may affect the welding quality, it is necessary to control the torch angle to be approximately constant.

[0049] Therefore, the torch position determination unit 605 of the control device 600 determines the torch position based on the torch position information (torch position determination step), and determines the relationship between the guide rail 120 and the polygonal square steel pipe W that has been input in advance to the control device 600. o Based on the information such as the size and shape of the torch, the torch angle deviation amount θ T(torch angle calculation step). The calculated deviation amount of the torch angle is input to the control device 600 as a torch angle correction value, and the crank 170, which is the movable part, rotates as shown by the arrow R2 in FIG. 3 to correct the deviation amount of the torch angle (torch angle control step).

[0050] The position information input to the torch position determination unit 605 for determining the torch position is acquired by using a sensing function such as a laser sensor. o The size of the rail may be recognized by the control device 600, and the rail size may be manually input to the control device 600, or the teaching point positions pre-stored in the data storage unit 601 may be obtained as position information.

[0051] Polygonal rectangular steel pipes at work sites o The actual relative position of the guide rail 120 is determined by the polygonal square steel pipe W o And the manufacturing error of the guide rail 120 and the polygonal square steel pipe W o Misalignment may occur due to an installation error of the guide rail 120 relative to the workpiece W. For this reason, it is preferable that the torch position determination unit 605 makes a determination taking this misalignment into consideration. o It is preferable to obtain the position information of the guide rail 120 by a sensing function, since the influence of the deviation is eliminated. The sensing function is not particularly important, and it is preferable to determine the torch position by using at least one sensing method of touch sensing, laser sensing, and visual sensing, or by combining these sensing methods.

[0052] The torch angle calculation unit 606 is configured to calculate the workpiece angle based on the workpiece information, the guide rail information, and the workpiece W. o and calculates the torch angle based on position information of guide rail 120. These pieces of information may be information obtained by sensing or the like, or may be numerical data of each piece of information stored in advance in data storage unit 601.

[0053] <How to calculate the torch angle> Next, a method for calculating the torch angle will be described in detail with reference to FIGS.

[0054] Here, the guide rail 120 is, for example, a guide rail 120 with RA=261 mm, and a polygonal square steel pipe W o We will explain an example in which a BCR polygonal square steel pipe is used as a concrete pipe. o There are BCR and BCP types, but the polygonal rectangular steel pipe W o However, the radius of curvature in relation to the plate thickness is determined by standards.

[0055] FIG. 6 shows a guide rail 120 (rail) and a polygonal rectangular steel pipe W o 1 is a diagram showing a 1 / 4 corner area of ​​the column, and the center line R of the guide rail 120 is c , and polygonal rectangular steel pipe W o Center line W c As shown in FIG. 6, the center of curvature of the quadrant of the guide rail 120 is O A , the radius of curvature is RA, the polygonal rectangular steel pipe W o The center of curvature of the corner quadrant is O B , radius of curvature is RB, and center of curvature is O. B The X coordinate of d1 is the center of curvature O B The Y coordinate of the welding robot 100 is d2. The portable welding robot 100 is located at point A on the guide rail 120. The center of curvature O A The angle between the line segment LA connecting point A and the X-axis is θ, and the center of curvature O B The angle between the line segment LB connecting point A and the X-axis is represented as θ1. o 6. In the second and fourth quadrants (not shown) in FIG. 6, the straight line portion WL is a parallel straight line portion as shown in FIG. 5. Since the torch angle in the second and fourth quadrants (not shown) in FIG. 6 is 0° and does not change, these quadrants are not covered by this description.

[0056] Assuming that the portable welding robot 100 moves counterclockwise from point A0 on the X-axis, which corresponds to the boundary point 128 in FIG. 5, the line segment LA intersects the polygonal square steel pipe W oIn the section until passing through the boundary point B0 between the straight line section WL and the corner section WC, i.e., in the second region II, the torch angle correction amount θ T = θ, and the line segment LA is between points B0 and B1, i.e., in the third region III, the torch angle correction amount θ T =θ-θ1, and the torch angle correction amount θ in the second region II is expressed as the distance from the boundary point B1 between the corner portion WC and the straight line portion WL until the line segment LA coincides with the Y axis. T =90°-θ.

[0057] Torch angle correction amount θ in the second region II T The torch angle correction amount θ in the third region III, where the line segment LA is between points B0 and B1, i.e., 0≦θ1<90°, can be easily calculated if the angle θ between the line segment LA and the X-axis is known. T This article will go into detail about:

[0058] In the third region III, the torch angle correction amount θ T = θ-θ1, so tan θ T =tan(θ-θ1)=(tanθ-tanθ1) / (1+tanθ×tanθ1). Therefore, we get equation (1). θ T =tan -1 (tanθ-tanθ1) / (1+tanθ×tanθ1)...(1)

[0059] Here, the XY coordinates of point A are (RAcosθ, RAsinθ), as shown in equation (2). tanθ1=(RAsinθ-d2) / (RAcosθ-d1)...(2)

[0060] Substituting equation (2) into equation (1), we get equation (3). θ T =tan-1(tanθ-((RAsinθ-d2) / (RAcosθ-d1)) / (1+tanθ×((RAsinθ-d2) / (RAcosθ-d1)))...(3) It should be noted that equation (3) is valid only in the range of 0≦θ1<90°.

[0061] Here, the radius of the guide rail 120 is RA = 261 mm, and the polygonal square steel pipe W o By substituting the radius RB = 62.5 mm, d1 = 40 mm, and d2 = 40 mm of the corner WC into formula (3), the angle θ and the torch angle correction amount θ are obtained. T The relationship can be obtained as shown in FIG.

[0062] Furthermore, the relationship "D = θ (rad) × RA" is established between the angle θ between the line segment LA and the X-axis and the travel distance D from point A0 on the guide rail 120 of the portable welding robot 100. Therefore, the angle θ between the line segment LA and the X-axis can be converted to the travel distance D (mm) from point A0. The travel distance D (mm) and the torch angle correction amount θ T The relationship is as shown in FIG.

[0063] Therefore, as shown in Figs. 7 and 8, in the range of 0°≦θ<45° and 0mm≦D<205mm, the torch angle correction amount θ T The torch angle is corrected to the forward angle side by the amount of the torch angle correction θ in the range of 45°≦θ<90° and 205mm≦D<410mm. T By correcting the torch angle to the rear advance angle side by this amount, the torch angle is maintained at a constant angle. Note that the position where θ=9°, i.e., D=41 mm, and the position where θ=81°, i.e., D=369 mm, correspond to the boundary point WB between the straight line portion WL and the corner portion WC shown in Figure 5.

[0064] This allows the work W o The corner portion WC of the workpiece W and the curved portion 122 of the guide rail 120 are not concentric. o Even when there is a large difference in curvature between the corner WC and the curved portion 122 of the guide rail 120, welding can be performed at a substantially constant torch angle over the entire circumference of the welded portion, ensuring a good bead appearance.

[0065] (Other welding conditions) In order to maintain a substantially constant weld quality over the entire length of the weld, it is preferable that other welding conditions, including the torch angle, be substantially constant as well. Other welding conditions are as follows: the portable welding robot 100 is welding a polygonal square steel pipe W o Before the start of welding, the welding conditions during welding can be acquired using the robot body 110 moving along the guide rail 120. That is, based on the operation signal of the control device 600, the robot body 110 is driven, the groove shape is automatically sensed by the touch sensor, the groove condition calculation unit 602 calculates groove shape information, and further based on the groove shape information and the teaching data held by the data storage unit 601, the welding condition calculation unit 603 calculates the welding conditions. The groove shape information includes, for example, the groove shape, plate thickness, and start and end points, and the welding conditions include, for example, the welding current, arc voltage, tip-base metal distance, and welding speed. Note that welding may be performed based on teaching data of welding conditions set in advance for each teaching point position on the guide rail, without automatic sensing of the groove shape.

[0066] Torch position information can also be acquired from teaching point positions on the guide rail that are stored in advance in the data storage unit 601. Examples of torch position information include straight sections, curved sections, boundary points, and torch angles of the guide rail. This information may be acquired by a detection means such as an image sensor or a laser sensor, or a combination of these detection means.

[0067] For example, in order to keep the deposition rate approximately constant over the entire length of the weld, the robot speed of the portable welding robot 100 calculated by the welding condition calculation unit 603 is controlled so that the robot speed on the curved portion 122 of the guide rail 120 is faster than the robot speed on the straight portion 121. Basically, the robot speed changes based on the teaching points, and the speed between the teaching points should be changed, for example, in a curved, linear, or stepped manner. The robot speed of the portable welding robot 100 specifically refers to the traveling speed of the portable welding robot 100 in the X direction on the guide rail 120.

[0068] That is, the robot speed V o is the radius of curvature RA of the curved portion 122 of the guide rail 120 and the polygonal square steel pipe W o The ratio RA / RB of the curvature radius RB of the corner WC and the set robot speed V set in the straight section 121 c Product V o =V c ×(RA / RB). Speed ​​control unit 604 controls the robot speed of portable welding robot 100 based on the robot speed calculated by welding condition calculation unit 603.

[0069] In addition, in the second region II and the third region III, the polygonal rectangular steel pipe W o The amount of heat input varies with the amount of heat input in the first region I. For this reason, the welding conditions are controlled so that the amount of heat input in the second region II and the third region III are within a range of ±20% with respect to the amount of heat input in the first region I. o The heat input in the straight section WL and the corner section WC is controlled to be approximately constant, and the welding conditions are maintained approximately constant, so that the polygonal square steel pipe W o The appearance of the joint at the straight portion WL and the corner portion WC is the same. The welding conditions referred to here include, for example, the robot speed, the welding current, the welding voltage, and the extension length, and are one or more conditions selected from these.

[0070] The present invention is not limited to the above-described embodiment, and modifications and improvements are possible as appropriate.

[0071] For example, in the above embodiment, sensing is performed using a touch sensor, but sensing may also be performed using other sensors such as a laser sensor, a visual sensor, or a combination of these.

[0072] In the above-described embodiment, the data used for setting the welding conditions is configured to be automatically set by automatic sensing. However, it may be input to the control device 600 in advance by teaching or the like.

[0073] Also, the polygonal square steel pipe W o and the shape of the guide rail 120 may be converted into the XY coordinate system from CAD data, or may be converted into the XY coordinate system based on sensing. Further, the shape information of the polygonal square steel pipe W o and the guide rail 120 may be input to the data holding unit 601 in advance, and may be converted into the XY coordinate system based on the shape information.

[0074] Also, in the above-described embodiment, the radius of curvature RA of the curved portion 122 of the guide rail 120 is described as being larger than the radius of curvature RB of the corner portion WC of the polygonal square steel pipe W o , that is, in the case of RA>RB. However, even when the radius of curvature RA of the curved portion 122 of the guide rail 120 is smaller than the radius of curvature RB of the corner portion WC of the polygonal square steel pipe W o , that is, in the case of RA<RB, the present invention can be similarly applied.

[0075] As described above, the following matters are disclosed in this specification.

[0076] (1) A control method for a portable welding robot using a welding system having a portable welding robot that installs a guide rail for a workpiece having a corner portion and moves on the guide rail to arc-weld the workpiece, and a welding control device that controls the portable welding robot, wherein the portable welding robot has a welding torch and a movable portion that moves the welding torch in the welding line direction, the welding control device has a torch position determination unit that determines a torch position on the workpiece and a torch angle calculation unit that calculates a torch angle at the torch position, a step of determining a torch position on the workpiece by the torch position determination unit, Calculating a torch angle at the torch position by the torch angle calculation unit; controlling the torch angle by the movable part based on the calculated torch angle; A method for controlling a portable welding robot comprising the steps of: With this configuration, even if the corner of the workpiece and the curved portion of the guide rail are not concentric and there is a large difference in curvature between the corner of the workpiece and the curved portion of the guide rail, the torch angle can be controlled to an approximately constant angle to ensure a good bead appearance.

[0077] (2) A method for controlling a portable welding robot as described in (1), characterized in that the torch position determination unit determines the torch position by at least one sensing means selected from the group consisting of touch sensing, laser sensing, and visual sensing, or determines the torch position based on a predetermined teaching point position. According to this configuration, the torch position can be automatically determined by the sensing function, and the torch position can be determined from the teaching data stored in the data storage unit.

[0078] (3) A method for controlling a portable welding robot as described in (1) or (2), characterized in that the torch angle calculation unit calculates the torch angle based on work information, guide rail information, and positional information of the work and the guide rail. With this configuration, the change in torch angle that occurs at the curved section of the guide rail can be calculated, and by controlling the torch angle, it is possible to improve the bead appearance at straight sections, corners, and the boundaries between corners and straight sections on the workpiece.

[0079] (4) The welding control device includes a welding condition calculation unit, The method for controlling a portable welding robot according to any one of (1) to (3), further comprising controlling the torch angle and welding conditions at the torch position. According to this configuration, welding can be performed under optimal welding conditions according to each welding position.

[0080] (5) The control method for a portable welding robot according to (4), wherein the control of the welding conditions includes controlling at least one of the welding current, the arc voltage, the tip-base metal distance, and the robot moving speed. According to this configuration, it is possible to select optimum welding conditions for each welding position and perform welding.

[0081] (6) A method for controlling a portable welding robot according to any one of (1) to (5), characterized in that the movable part controls the torch angle so that the torch angle in straight portions and corners of the workpiece is approximately constant based on the torch angle in straight portions of the workpiece. With this configuration, even if the corner of the workpiece and the curved portion of the guide rail are not concentric and there is a large difference in curvature between the corner of the workpiece and the curved portion of the guide rail, the torch angle can be maintained approximately constant, ensuring a good bead appearance.

[0082] (7) A control method for a portable welding robot described in (3), characterized in that the torch angle calculation unit calculates the torch angle based on a radius of curvature value at a corner of the workpiece at the torch position and a radius of curvature value at a curved portion of the guide rail. According to this configuration, the deviation angle of the torch angle at each welding position can be accurately calculated.

[0083] (8) A control method for a portable welding robot described in (4) or (5), characterized in that the welding conditions are controlled so that the heat input to the corner portion and the heat input to the boundary region between the straight portion and the corner portion are each within a range of ±20% relative to the heat input to the straight portion of the workpiece. With this configuration, even if the corner of the workpiece and the curved portion of the guide rail are not concentric and there is a large difference in curvature between the corner of the workpiece and the curved portion of the guide rail, a good bead appearance can be ensured by controlling the amount of heat input.

[0084] (9) A welding control device for controlling a portable welding robot that is provided with a guide rail for a workpiece having a corner and moves on the guide rail to arc-weld the workpiece, comprising: A torch position determination unit that determines a torch position on the workpiece, and a torch angle calculation unit that calculates a torch angle at the torch position, The torch position determination unit determines a torch position on the workpiece, The torch angle calculation unit calculates a torch angle at the torch position, A welding control device characterized in that the torch angle is controlled based on the calculated torch angle. With this configuration, even in areas where the corners of the workpiece and the curved portions of the guide rail are not concentric and there is a large difference in curvature between the corners of the workpiece and the curved portions of the guide rail, the torch angle can be maintained approximately constant, ensuring a good bead appearance.

[0085] (10) A portable welding robot controlled by the welding control device according to (9) above, which is configured to install a guide rail for a workpiece having a corner and move along the guide rail to arc-weld the workpiece, A welding torch and a movable part that moves the welding torch in a welding line direction, The portable welding robot is characterized in that the movable part controls the torch angle based on the torch angle calculated by the torch angle calculation part. According to this configuration, the angular deviation of the torch angle at each welding position can be corrected by the movable part, making it possible to perform welding at a substantially constant torch angle.

[0086] (11) A welding system including a portable welding robot that is provided with a guide rail for a workpiece having a corner and moves on the guide rail to arc-weld the workpiece, and a welding control device that controls the portable welding robot, The portable welding robot has a welding torch and a movable part that moves the welding torch in a weld line direction, The welding control device has a torch position determination unit that determines a torch position on the workpiece, and a torch angle calculation unit that calculates a torch angle at the torch position, The torch position determination unit determines a torch position on the workpiece, The torch angle calculation unit calculates a torch angle at the torch position, A welding system comprising: a movable part that controls the torch angle based on the calculated torch angle. According to this configuration, the torch angle calculation unit calculates the angular deviation of the torch angle at each welding position, and the movable unit controls the torch angle to correct the angular deviation, thereby enabling welding to be performed at a substantially constant torch angle.

[0087] (12) A method for controlling a portable welding robot using a welding system including a guide rail provided for a polygonal square steel pipe, a portable welding robot that moves on the guide rail to arc-weld the polygonal square steel pipe, and a welding control device that controls the portable welding robot, comprising: The portable welding robot has a welding torch and a movable part that moves the welding torch in a weld line direction, The welding control device has a torch position determination unit that determines a torch position on the polygonal square steel pipe, and a torch angle calculation unit that calculates a torch angle at the torch position, A step of determining a torch position on the polygonal square steel pipe by the torch position determination unit; Calculating a torch angle at the torch position by the torch angle calculation unit; controlling the torch angle by the movable part based on the calculated torch angle; A method for controlling a portable welding robot comprising the steps of: With this configuration, a portable welding robot installed on a guide rail can weld the entire circumference of the weld portion of the polygonal square steel pipe at a substantially constant torch angle, ensuring a good bead appearance. [Explanation of symbols]

[0088] 50 Welding System 100 Portable welding robot 120 Guide Rail 121 (of guide rail) straight section 122 (guide rail) curved section 128 (guide rail) boundary point 170 Crank (moving part) 200 Welding Torch 300 Feeding device 400 Welding power source 500 Shielding gas supply source 600 Control device (welding control device) 603 Welding condition calculation section 605 Torch position determination unit 606 Torch angle calculation unit d1 Center of curvature O B X coordinate of d2 Center of curvature O B Y coordinate of LA center of curvature O A and the line segment connecting point A LB Center of curvature O B and the line segment connecting point A O A Center of curvature of curved section (of guide rail) O B Center of curvature of corner (of workpiece) RA: Radius of curvature at the curved section of the guide rail RB Radius of curvature at the corner of the workpiece W o Workpiece (polygonal square steel pipe) WL (Workpiece) Straight section WC (Workpiece) Corner (Curved) WB (Work) Boundary Point I 1st area II 2nd area III Third area θ The angle between the line segment LA and the X-axis θ1 Angle between line segment LB and the X-axis θ T Torch angle correction amount

Claims

1. A method for controlling a portable welding robot using a welding system including a guide rail for a workpiece having a corner, a portable welding robot that moves on the guide rail to arc-weld the workpiece, and a welding control device that controls the portable welding robot, comprising: The portable welding robot has a welding torch and a movable part that moves the welding torch in a weld line direction, The welding control device includes: A torch position determination unit that determines a torch position on the workpiece; a torch angle calculation unit for calculating a torch angle at the torch position; having acquiring position information of at least the workpiece and the guide rail based on at least one sensing means selected from the group consisting of touch sensing, laser sensing, and visual sensing; determining a torch position on the workpiece by the torch position determination unit; a first region in which a position of the portable welding robot on the guide rail and a position of the welding torch on the workpiece are both on a straight line; a second region in which one of a position of the portable welding robot on the guide rail and a position of the welding torch on the workpiece is on a straight line portion and the other is on a curved line portion; a third region in which a position of the portable welding robot on the guide rail and a position of the welding torch on the workpiece are both on a curved portion; and dividing the area into Calculating a torch angle at the torch position for each of the regions based on position information of at least the workpiece and the guide rail by the torch angle calculation unit; controlling the torch angle by the movable part based on the calculated torch angle; A method for controlling a portable welding robot comprising the steps of:

2. 2. The method for controlling a portable welding robot according to claim 1, wherein the torch position determination unit determines the torch position by the sensing means, or determines the torch position based on a predetermined teaching point position.

3. 3. The method for controlling a portable welding robot according to claim 1, wherein the torch angle calculation unit calculates the torch angle based on work information and guide rail information.

4. the welding control device includes a welding condition calculation unit that calculates welding conditions other than the torch angle at the torch position, 2. The method for controlling a portable welding robot according to claim 1, wherein the control of the other welding conditions comprises controlling at least one of a welding current, an arc voltage, a tip-base metal distance, and a robot moving speed.

5. 5. The method for controlling a portable welding robot according to claim 1, wherein the movable part controls the torch angle based on the torch angle in the straight portion of the workpiece as a reference so that the torch angle in the straight portion and the corner portion of the workpiece is approximately constant.

6. 4. The control method for a portable welding robot according to claim 3, wherein the torch angle calculation unit calculates the torch angle based on a radius of curvature value at a corner of the workpiece at the torch position and a radius of curvature value at a curved portion of the guide rail.

7. The control method for a portable welding robot according to any one of claims 1 to 6, characterized in that the other welding conditions are controlled so that the heat input to the corner portion and the heat input to the boundary area between the straight portion and the corner portion are each within a range of ±20% relative to the heat input to the straight portion of the workpiece.

8. A welding control device for controlling a portable welding robot that installs a guide rail for a workpiece having a corner and moves on the guide rail to arc-weld the workpiece, A torch position determination unit that determines a torch position on the workpiece; a torch angle calculation unit for calculating a torch angle at the torch position; having acquiring position information of at least the workpiece and the guide rail based on at least one sensing means selected from the group consisting of touch sensing, laser sensing, and visual sensing; The torch position determination unit determines a torch position on the workpiece, a first region in which a position of the portable welding robot on the guide rail and a position of the torch on the workpiece are both on a straight line; a second region in which one of a position of the portable welding robot on the guide rail and a position of the torch on the workpiece is on a straight line portion and the other is on a curved line portion; a third region in which a position of the portable welding robot on the guide rail and a position of the torch on the workpiece are both on a curved portion; Divided into the following areas: The torch angle calculation unit calculates a torch angle at the torch position for each of the regions based on position information of at least the workpiece and the guide rail, A welding control device characterized in that the torch angle is controlled based on the calculated torch angle.

9. A portable welding robot controlled by the welding control device according to claim 8, which is configured to install a guide rail for a workpiece having a corner, and move on the guide rail to arc-weld the workpiece, A welding torch and a movable part that moves the welding torch in a welding line direction, The portable welding robot is characterized in that the movable part controls the torch angle based on the torch angle calculated by the torch angle calculation part.

10. A welding system including: a portable welding robot that is provided with a guide rail for a workpiece having a corner, and that moves on the guide rail to arc-weld the workpiece; and a welding control device that controls the portable welding robot, The portable welding robot has a welding torch and a movable part that moves the welding torch in a weld line direction, The welding control device includes: A torch position determination unit that determines a torch position on the workpiece; a torch angle calculation unit for calculating a torch angle at the torch position; having acquiring position information of at least the workpiece and the guide rail based on at least one sensing means selected from the group consisting of touch sensing, laser sensing, and visual sensing; The torch position determination unit determines a torch position on the workpiece, a first region in which a position of the portable welding robot on the guide rail and a position of the welding torch on the workpiece are both on a straight line; a second region in which one of a position of the portable welding robot on the guide rail and a position of the welding torch on the workpiece is on a straight line portion and the other is on a curved line portion; a third region in which a position of the portable welding robot on the guide rail and a position of the welding torch on the workpiece are both on a curved portion; Divided into the following areas: The torch angle calculation unit calculates a torch angle at the torch position for each of the regions based on position information of at least the workpiece and the guide rail, A welding system comprising: a movable part that controls the torch angle based on the calculated torch angle.

11. A method for controlling a portable welding robot using a welding system including a guide rail for a polygonal square steel pipe, a portable welding robot that moves on the guide rail to arc-weld the polygonal square steel pipe, and a welding control device that controls the portable welding robot, The portable welding robot has a welding torch and a movable part that moves the welding torch in a weld line direction, The welding control device includes: A torch position determination unit that determines a torch position on the polygonal square steel pipe; a torch angle calculation unit for calculating a torch angle at the torch position; having acquiring position information of at least the workpiece and the guide rail based on at least one sensing means selected from the group consisting of touch sensing, laser sensing, and visual sensing; A step of determining a torch position on the polygonal square steel pipe by the torch position determination unit; a first region in which a position of the portable welding robot on the guide rail and a position of the welding torch on the workpiece are both on a straight line; a second region in which one of a position of the portable welding robot on the guide rail and a position of the welding torch on the workpiece is on a straight line portion and the other is on a curved line portion; a third region in which a position of the portable welding robot on the guide rail and a position of the welding torch on the workpiece are both on a curved portion; and dividing the area into Calculating a torch angle at the torch position for each of the regions based on position information of at least the workpiece and the guide rail by the torch angle calculation unit; controlling the torch angle by the movable part based on the calculated torch angle; A method for controlling a portable welding robot comprising the steps of:

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