JP2003200263A - Method for automatically operating welding robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method or automatically operating a welding robot by which the formation of a weld joint with a welding defect is preliminarily prevented. <P>SOLUTION: The method for automatically operating the welding robot includes a step for inputting data of the shape of groove of a weld joint 5 of at least two points in the longitudinal direction of welding Y, a step for calculating the tilt of the weld joint in the longitudinal direction of welding Y from the data of the shape of the groove of the weld joint 5, a step for performing a welding under an appropriate welding condition calculated from the data of the shape of the groove when the calculated tilt of the weld joint is within an allowable range, and a step for shifting the welding to a next weld joint when the tilt of the weld joint is out of the allowable range. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for automatically operating a welding robot for preventing the formation of a welded joint that causes poor welding. [0002] Conventionally, a predetermined portion of a welded joint (start of welding)
At the end position), the groove shape data is captured by the touch sensor function, the groove cross-sectional area is calculated from the both groove shape data, and the number of welding passes is calculated from the calculated groove cross-sectional area. There is known a welding robot that calculates welding conditions corresponding to a groove cross-sectional area of a welding path (Japanese Patent Application Laid-Open No. 09-10939). In this prior art, the optimum number of welding passes is calculated in accordance with the variation in the groove cross-sectional area of a welded joint, and the optimum welding conditions for each welding pass are calculated and the welding is executed. A high quality welded joint can be formed. However, in the prior art, when the weld joint is inclined in the longitudinal direction of the weld due to a work assembly error or a work installation error, the welding beat becomes up and down welding and the welding beat is reduced. There is a problem that uneven welding causes poor welding such as insufficient penetration. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for automatically operating a welding robot that prevents the formation of a welded joint that causes poor welding. Accordingly, a first aspect of the present invention is to capture groove shape data of at least two welded joints in the longitudinal direction of welding and to obtain groove shape data of these welded joints from the welded joint shape data. The inclination of the weld joint in the welding longitudinal direction is calculated, and if the calculated inclination of the weld joint is within an allowable range, welding is performed under appropriate welding conditions calculated from the groove shape data, and the inclination of the weld joint is calculated. If is outside the permissible range, the process is shifted to the next welded joint. An embodiment according to the present invention will be described below with reference to FIGS. FIG. 1 shows a welding robot that implements the automatic driving method according to the embodiment of the present invention.
As shown in FIG. 1, the robot comprises a robot body 1, a welding power source 2, and a robot controller 10. The robot body 1 is, for example, a 6-axis vertical articulated type, and includes a DC motor (not shown) for swinging each arm (not shown) (not shown) and a position thereof. A detector is provided, and a welding torch 3 is provided at a tip of a wrist (not shown) (not shown). In addition, the robot main body 1 includes a robot main body control unit 41 of the robot control device 10 described later.
Each of the arms is operated in response to a position control signal from the robot, and the leading end of the welding torch 3 (not shown) is reproduced based on the teaching program execution data. The welding power source 2 is, for example, of a carbon dioxide shield consumable electrode welding type, and includes a welding power supply unit (not shown) and a sensing power supply unit (not shown). The welding power source 2 receives a welding start / end command, a welding voltage / current welding condition command from a welding power source control unit 43 of the robot controller 10 described later, and the like. The work is supplied to an omitted work (hereinafter abbreviated as “work”). The wire 4 fed from the welding torch 3 is supplied from a wire feeder (not shown). Further, the workpiece is, for example, a construction machine part formed of a root gap downward butt welded joint 5 (hereinafter referred to as a “root gap welded joint”) shown in FIG. The target is a steel connection member formed by the above method. [0010] The robot control device 10 includes the arithmetic processing device 2
0, a storage device 30, a control device 40 such as the robot main body 1 and the welding power source 2, and an input device 50. The arithmetic processing unit 20 comprises a robot operation arithmetic unit 21, a route gap arithmetic unit 22, a weld joint inclination arithmetic unit 23, and a welding condition arithmetic unit 24. The robot operation calculation unit 21 sequentially reads out the teaching program execution data stored in the teaching program storage unit 31 of the storage device 30 described later, and outputs a calculation command to each device related to the execution of each execution data. It has become. In this embodiment, the robot operation calculation unit 2
Reference numeral 1 denotes, for example, a gap sensing command on the welding start / end side of the root gap welding joint 5 of the work, and the root gap calculating unit 22 uses the gap sensing position information on the welding start / end side to form a groove on the welding start / end side. The center position information Ps and Pe (see FIG. 2A) are calculated, and the inclination of the root gap weld joint 5 in the welding longitudinal direction X (hereinafter referred to as “the inclination of the weld joint”) is calculated by the weld joint inclination calculator 23.
Is calculated. Also. The robot operation calculation unit 21 determines that the inclination of the root gap weld joint 5 calculated by the weld joint inclination calculation unit 23 is within the allowable value of the allowable inclination angle set by the allowable weld joint inclination setting unit 44 of the control device 40 described later. Is determined. Then, the robot operation calculating unit 21 sends the welding condition calculating unit 24 the optimum welding path according to the variation of the groove cross-sectional area of the root gap welded joint 5 based on the determination result that the angle is within the allowable angle of the welded joint inclination calculating unit 23. The number and the calculated welding conditions for each welding pass are calculated and the welding is performed. The robot operation calculation unit 21 confirms the presence or absence of the next welded joint from the teaching program execution data stored in the teaching program storage unit 31 based on the determination result that the angle is outside the allowable angle of the welded joint inclination calculation unit 23, and If there is no joint, the teaching program is terminated.
When there is a weld joint, the robot operation calculation unit 21 sequentially reads out the next teaching program execution data of the weld joint and executes each execution data. The route gap calculating section 22 instructs the robot operation calculating section 21 to perform a predetermined sensing operation and causes the robot main body 1 to perform a gap sensing operation, as described in Japanese Patent Application Laid-Open No. 05-329644. From the position information in the robot coordinate system based on the detection signal from the cap sensing detection control unit 42 of the control device 40 described later, the root gap width Ws on the welding start / end side,
We and root gap center positions Ps and Pe are calculated. That is, the root gap calculating section 22
The detection positions P7, P8 on the surfaces of the grooves 6b, 7b of the left and right weld joint forming members 6, 7 by the cap sensing operation on the welding start side shown in (b), and the set plate thickness t and groove of the left weld joint 6 6b, 7b From left and right angles θ1, θ2, 6
b, 7b root face part position information Ps1 (XPs1, YP
S1 and ZPs1) and Ps2 (XPs2, YPS2 and ZPs2) are calculated, and the Y-axis position information (YPS1 and YPS2) of both root face position information Ps1 and Ps2 is changed to the Y direction (see FIG. 2B). The root gap width Ws is calculated. Further, the route gap calculation unit 22 calculates the Y-axis position information (YPS1, YP) of both root face position information Ps1 and Ps2.
The root gap center position Ps (XPs, YPS, ZPs) obtained by equally dividing (SPS) by (YPS1−YPS2 / 2) is calculated. The root gap calculation unit 22 calculates the root gap width Ws on the welding start side and the root gap center position Pe (XPe, YPe, ZPe) in the same manner. The welding joint inclination calculating section 23 calculates the inclination angle [K of the welding joint in the welding longitudinal direction Y (see FIG. 2A) from the two root gap center position information Ps and Pe calculated by the root gap calculating section 22. ] Is calculated by the following equation (1). [K] = (ZPe−ZPs) / SQRT ((XPe−XPs) ↑ 2 + (YPe−YPs) ↑ 2 + (ZPe−ZPs) ↑ 2 (1) Further, the weld joint inclination calculator 23 calculates the calculated welding The joint inclination angle [K] and the allowable inclination angle [Ks] set in the allowable welding joint inclination setting unit 44 of the control device 40 described later.
Is determined to be within the allowable value. The welding condition calculation unit 24 stores, for example, the plate thickness t and the groove 6a, 7a angle θ of the left welding joint component 6 set in the groove condition storage unit 32 of the storage device 30 described later.
1, θ2, the root gap width Ws on the welding start side and / or
Alternatively, the groove cross-sectional area is calculated from the root gap width We on the welding end side, and the optimum welding path that matches the groove angle and the root gap width range for each of the various welded joints stored therein and the optimum welding path for each welding path. A match or close one is selected from a welding condition algorithm consisting of welding conditions. The storage device 30 includes a teaching program storage unit 3
1, a groove condition storage unit 32, and a primary storage unit 33. The teaching program storage unit 31 stores teaching program execution data of each work taught by the operator, and reads the teaching program execution data to the robot operation calculation unit 21 according to the input of the setting of the teaching program number by the operator. ing. The groove condition storage unit 32 stores, for example, the joint components 6 of the root gap welded joint 5 set and inputted.
(7) Plate thickness t and groove angles θ1 and θ2 of grooves 6a and 7a
Are stored, and each set value is output to the route gap calculation unit 22 according to a command from the robot operation calculation unit 21. The primary storage unit 33 is adapted to temporarily store various data used when performing calculations in each processing unit of the processing unit 20. The control device 40 includes a robot body control unit 41
, A gap sensing detection control unit 42, a welding power supply control unit 43, and an allowable welding joint inclination setting unit 44. The robot main body controller 41 includes an input device 50
Each arm or the like of the robot main body 1 is controlled for each axis operation or playback operation in accordance with a command from the robot or a teaching program execution data from the robot operation calculation unit 21. The gap sensing detection control unit 42 is provided with a predetermined sensing operation (see FIG. 2B) by the robot body 1, that is, the welding torch 3, as described in Japanese Patent Application Laid-Open No. 05-329644. The contact between the surface 6a of the left weld joint forming member 6 and the surfaces 6b and 7b of the grooves 6b and 7b of the left and right weld joint forming members 6 and 7 by the wire tip 4a protruding from the welding torch 3 is detected. It has become. The contact of the wire tip 4a is confirmed when the sensing voltage applied to the workpiece from the unillustrated sensing power supply unit of the welding power supply 2 and the welding torch 3 becomes substantially zero volt. . The welding power source control unit 43 receives welding start / end commands, welding voltage / current welding condition commands and the like from the welding power source 2 according to the teaching program execution data, and transmits the welding power of the welding condition commands to the welding torch 3 and the work. And to supply to. Further, the welding power source control unit 43 outputs to the welding power source 2 the welding conditions of each welding path of the optimal welding path selected by the welding condition calculation unit 24. The allowable joint angle setting section 44 outputs ± 5 degrees of the allowable allowable angle [Ks] set in advance to the weld joint angle calculating section 23 in accordance with a command from the robot operation calculating section 21. The reason for setting the allowable inclination angle [Ks] is that, first, when the welding end side Pe is inclined by +5 degrees or more with respect to the welding start side Ps to perform upward welding, welding proceeds in a state where the molten pool is biased behind the arc. When the arc is deflected backward, the penetration deepens due to the heat of the arc and the heat of the molten pool, but the weld bead becomes a convex beat, and the molten pool does not adapt to both grooves 6b and 7b, and insufficient penetration occurs. Will do. On the other hand, when the welding is inclined downward by -5 degrees or more, the welding proceeds in a state where the molten pool is biased forward of the arc, so that the arc is deflected forward. Although it becomes a prominent concave beat and adapts to both the grooves 6b and 7b, an arc force is applied in the longitudinal direction of the weld and the molten pool precedes, so that insufficient penetration of the weld bead occurs. The input device 50 is, for example, a teaching pendant. With this input device 50, the operator can input each axis operation of each arm of the robot main body 1 and can teach the teaching operation of each work. . From this input device 50, the teaching program No.
Etc. are set and input. Next, an automatic operation method of the welding robot having such a configuration will be described. First, a work made up of a plurality of root gap welded joints 5 is set at a predetermined position by an operator, and a teaching program No of the work is set and input by the operator from the input device 50 and is started (S1). . Then, the teaching program execution data of the teaching program No. set by the robot operation calculation section 21 is sequentially read from the teaching program storage section 31, and the robot body is controlled in the order based on the teaching program execution data via the robot body control section 41. 1 is played (executed) (S2). The execution of the teaching program proceeds, and the root gap arithmetic unit 22 causes the robot body 1 to perform a predetermined sensing operation via the robot operation arithmetic unit 21 based on the gap sensing execution data on the welding start side of the root gap weld joint 5. (S3), individual position information in the robot coordinate system based on the detection signal from the gap sensing detection control unit 42, and the joint component 6 (7) of the root gap weld joint 5 input from the groove condition storage unit 32 Sheet thickness t
And the root gap width Ws on the welding start side is calculated from the groove angles θ1 and θ2 of the grooves 6a and 7a (S4).
A root gap center position Ps is calculated from the calculated root gap width Ws (S5), and both calculated values are stored in the primary storage unit 33.
To memorize. Subsequently, the robot body 1 is similarly caused to perform a predetermined sensing operation based on the gap sensing execution data on the welding end side of the root gap welding joint 5 (S
6) The individual position information in the robot coordinate system based on the detection signal from the gap sensing detection control unit 42 and the joint constituent members 6 (7) of the root gap weld joint 5 input from the groove condition storage unit 32 Plate thickness t, groove 6a, 7a
The root gap width We on the welding start side is calculated from the groove angles θ1 and θ2 of (S7), and the root gap center position Pe is calculated from the calculated root gap width We (S7).
8) Store both operation values in the primary storage unit 33. The inclination angle [K] of the weld joint in the weld longitudinal direction Y (see FIG. 2A) is calculated by the weld joint inclination calculating unit 23 with the two root gap center positions Ps and Pe read from the primary storage unit 33. Is calculated (S9), and the calculated inclination angle [K] of the weld joint and the allowable inclination angle [Ks] input from the allowable weld joint inclination setting unit 44 determine whether the inclination of the root gap weld joint 5 is within the allowable range. It is determined whether or not (S10). As a result of the determination, when the inclination of the root gap welding joint 5 is within the allowable range (Yes), the welding condition calculation unit 2
4, the groove cross-sectional area of the root gap weld joint 5 is calculated, and the optimum welding path and the welding conditions of each welding path are selected from the calculated groove cross-sectional area of the root gap weld joint 5 (S11). The welding condition is output to the welding power source 2 via the welding power source control unit 43 in accordance with a command from the operation calculation unit 21, and the welding operation is performed in accordance with the regeneration operation of the welding torch 3 to the root gap welding joint 5 by the robot body 1. The welding of the root gap welding joint 5 is performed by the welding power supplied to the torch 3 and the work (1).
2). As a result, the optimum number of welding baths is selected according to the variation of the groove cross-sectional area of the root gap welded joint 5, and a root gap welded joint having no defects by welding each welding path under optimum welding conditions is obtained. Can be formed. After the welding is completed, the process proceeds to step S13 for confirming the presence or absence of the next welded joint. On the other hand, if the inclination of the root gap welded joint 5 is out of the allowable range (No), the robot operation computing unit 21 checks the presence or absence of the next welded joint from the teaching program execution data (S13). Is not available (Ye
s), the teaching program execution data ends, and the welding operation ends. As a result, the welded root gap welded joint 5 can be formed into a good welded joint, and repair welding of the welded root gap welded joint 5 in the next welding repairing step is not required. In the subsequent welding repair process, a groove forming operation using a glider or the like subsequent to gouging cutting is not required, and repair welding can be performed with a normal groove, and the repair welding work of the repair welding worker can be reduced. However, when there is the following welded joint (N
o) Then, the robot operation calculating section 21 continuously shifts to the next welding joint (S14), and if there is data for executing the teaching program at the next welding joint, gap sensing is performed on the welding start side. As a result, after the welding work of this work is completed, the root gap welded joint 5 that has not been welded in the next welding repairing step does not require a groove forming operation using a glider or the like subsequent to the gouging cutting, and is repaired with a normal groove. Welding is possible, and repair welding work of repair welding workers can be reduced. In the automatic operation method of the welding robot according to the above-described embodiment, the root gap sensing of the root gap welding joint 5 is performed by the touch sensor function. If it is a method that can obtain the calculation position information of the widths Ws and We,
Other than the touch sensor function may be used. Further, when the sensing position is not limited to the welding start / end sides Ps and Pe, and the root face portion has the same tendency due to individual differences of workpieces and assembly errors, for example, when the root face portion extends from the welding start side Ps to the welding longitudinal side, When the divergence expands toward the approximate center of the direction and then decreases toward the welding end side Pe, the sensing position is changed to the welding start / end sides Ps, Pe.
In addition to this, it is necessary to set the approximate center in the longitudinal direction of welding. The welding robot according to the above-described embodiment includes a positioner for positioning a work in a welding position within the operating range of the robot body 1 and a moving device for the robot body 1 for expanding the operating range of the robot body 1. A vertical lifting device may be provided. Then, the input device 5 in the above-described embodiment is used.
Instead of 0, a form using an off-line teaching device using a computer, for example, a personal computer may be used. As described above, according to the first aspect of the present invention, the groove shape data of at least two welded joints in the longitudinal direction of welding are acquired, and welding is performed from the groove shape data of these welded joints. The inclination of the weld joint in the longitudinal direction is calculated, and if the calculated inclination of the weld joint is within an allowable range, welding is performed under appropriate welding conditions calculated from the groove shape data, and the inclination of the weld joint is calculated. If it is out of the permissible range, it will move to the next welded joint.If the inclination of the welded joint calculated from the groove shape data is out of the permissible inclination, it will move to the next welded joint, resulting in poor welded joint. In addition to preventing weld formation and preventing welding of welded joints with out-of-tolerance inclinations, it is necessary to form a groove with a glider following gouging cutting in the next welding repair process Repair welding can be performed with a normal groove, and the repair welding work of repair welding workers can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a control block diagram of a welding robot in an embodiment according to the present invention. FIG. 2 is a view showing a welded joint according to the embodiment;
FIG. 7B is an oblique projection view, and FIG. 7B is an explanatory view of a gap sensing operation at a welding start side position. FIG. 3 is a flowchart illustrating a method of automatically operating a welding robot according to the embodiment. [Description of Signs] 1 Robot main body 5 Weld joint (root gap weld joint) 21 Robot operation calculation unit 22 Root gap calculation unit 23 Weld joint inclination calculation unit 24 Welding condition calculation unit Y Welding longitudinal direction

Claims (1)

Claims: 1. The groove shape data of at least two welded joints in the longitudinal direction of welding are taken in, and the inclination of the welded joint in the longitudinal direction of welding is calculated from the groove shape data of these welded joints. If the calculated inclination of the weld joint is within the allowable range, the welding is performed under the proper welding conditions calculated from the groove shape data, and if the inclination of the weld joint is outside the allowable range, the next welding is performed. An automatic driving method for a welding robot, characterized by shifting to a joint.