JP4727106B2 - Automatic operation method of welding robot - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for automatically operating a welding robot that prevents the formation of a weld joint that results in poor welding.
[0002]
[Prior art]
Conventionally, the groove shape data is taken in by a touch sensor function at a predetermined location (welding start / end position) of the welded joint, and the groove sectional area is calculated from the both groove shape data thus obtained, and the calculated groove cutting is performed. There is known a welding robot that calculates the number of welding passes from the area and calculates welding conditions corresponding to the groove cross-sectional area of each welding pass (Japanese Patent Laid-Open No. 09-10939).
[0003]
In this prior art, the optimum number of welding passes is calculated according to the fluctuation of the groove cross-sectional area of the welded joint, and the optimum welding conditions for each welding pass are calculated and welded to perform high-quality welding. A joint can be formed.
[0004]
[Problem to be Solved by the Invention]
However, in the conventional technology, when the welded joint is inclined in the longitudinal direction of the weld due to workpiece assembly error or workpiece mounting error, the welding beat becomes uneven due to up-down welding, resulting in poor welding such as insufficient penetration. There is a problem that occurs.
[0005]
Accordingly, an object of the present invention is to provide an automatic operation method of a welding robot that prevents the formation of a weld joint that causes poor welding.
[0006]
[Means for Solving the Problems]
Therefore, claim 1 of the present invention relates to downward welding of a welded joint having a straight weld line and an upward or downward inclination with respect to the horizontal plane, and at least in the longitudinal direction of the welding by a sensing operation before performing the welding. The groove shape data of the two welded joints on the welding start side and the welding end side are taken in, and at least the weld in the longitudinal direction of the weld is based on the root gap center position information calculated from the groove shape data of these welded joints. A horizontal straight line formed by projecting a straight line connecting two root gap center positions on the start side and the welding end side onto a horizontal plane including the root gap center position on the welding start side, and at least the welding in the welding longitudinal direction initiator and the a straight line connecting the root gap center position of the two positions of the welding end side, in the inclination angle of the root gap vertically formed As a calculation of the inclination of the weld joint, if the calculated inclination of the weld joint is within an allowable range, the welding is performed under appropriate welding conditions based on the groove sectional area calculated from the groove shape data, If the inclination of the welded joint is outside the allowable range, the process moves to the next welded joint.
According to a second aspect of the present invention, the route gap center position information is formed by projecting a straight line connecting the two root gap center positions on the welding start side and the welding end side in the welding longitudinal direction onto a horizontal plane. X direction is a horizontal direction to be performed, a Y direction is a horizontal direction formed by projecting a straight line in a width direction of a route gap for performing the sensing operation on a horizontal plane, and a vertical direction of the root gap for performing the sensing operation is a Z direction. By the sensing operation, the groove shape data of the weld joint at the two weld start sides and the weld end side in the longitudinal direction of the weld are taken in, and the root gap center position Ps (XPs, YPs, ZPs) of the weld joint on the weld start side And the root gap center position Pe (XPe, YPe, ZPe) of the weld joint on the welding end side,
The inclination of the weld joint is calculated by the following equation.
(ZPe−ZPs) / SQRT ((XPe−XPs) ↑ 2 +＋ (YPe−YPs) ↑ 2 + (ZPe−ZPs) ↑ 2)
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments according to the present invention will be described below with reference to FIGS. 1 to 3.
As shown in FIG. 1, a welding robot that performs an automatic driving method according to an embodiment of the present invention includes a robot body 1, a welding power source 2, and a robot control device 10.
[0008]
The robot body 1 is, for example, a 6-axis vertical articulated type, and includes a DC motor and a position detector (not shown) that swing each arm (not shown) (hereinafter abbreviated as “each arm”). A welding torch 3 is provided at the tip of the wrist (not shown) (hereinafter abbreviated as “tip of the wrist”). Further, the robot body 1 receives a position control signal from a robot body control unit 41 of the robot control apparatus 10 to be described later, and each arm is operated to regenerate the tip of the welding torch 3 (not shown) based on teaching program execution data. It is supposed to be.
[0009]
The welding power source 2 is, for example, a carbon dioxide shield consumable electrode welding method, and includes a welding power supply unit (not shown) and a sensing power source unit (not shown). The welding power source 2 receives a welding start / end command, a welding voltage / current welding condition command, and the like from a welding power source control unit 43 of the robot control device 10 to be described later. It is supplied to the omitted work (hereinafter abbreviated as “work”). The wire 4 fed out from the welding torch 3 is supplied from a wire feeding device (not shown). The workpiece may be, for example, a construction machine part formed by a root gap downward butt weld joint 5 (hereinafter referred to as a “root gap weld joint”) shown in FIG. The steel joint member etc. which are formed in is targeted.
[0010]
The robot control device 10 includes an arithmetic processing device 20, a storage device 30, a control device 40 such as the robot body 1 and the welding power source 2, and an input device 50.
[0011]
The arithmetic processing unit 20 includes a robot motion calculation unit 21, a route gap calculation unit 22, a weld joint inclination calculation unit 23, and a welding condition calculation unit 24.
[0012]
The robot motion calculation unit 21 sequentially reads teaching program execution data stored in a teaching program storage unit 31 of the storage device 30 to be described later, and outputs a calculation command to each device related to the execution of each execution data. Yes.
[0013]
In the present embodiment, for example, the robot motion calculation unit 21 sends a gap sensing position on the welding start / end side to the route gap calculation unit 22 by a gap sensing command on the welding start / end side of the workpiece root gap welded joint 5. In addition to calculating the groove center position information Ps, Pe (see FIG. 2A) on the welding start / end side from the information, the welding joint inclination calculating unit 23 inclines the welding gap in the longitudinal direction X of the root gap welded joint 5 (hereinafter referred to as “the welding gap direction”). , “Inclination of welded joint”). Also. The robot operation calculating unit 21 determines that the inclination of the root gap welded joint 5 calculated by the welded joint inclination calculating unit 23 is within the allowable value of the allowable inclination angle set by the allowable welded joint inclination setting unit 44 of the control device 40 described later. It is supposed to be judged. Then, the robot motion calculation unit 21 causes the welding condition calculation unit 24 to determine the optimum welding path according to the variation in the groove cross-sectional area of the root gap welded joint 5 based on the determination result of the allowable angle of the weld joint inclination calculation unit 23. The welding operation is performed by calculating the optimum welding condition for each welding pass calculated as the number. The robot operation calculation unit 21 confirms the presence or absence of the next weld joint from the teaching program execution data stored in the teaching program storage unit 31 based on the determination result that the weld joint inclination calculation unit 23 is outside the allowable angle, and performs the next welding. When there is no joint, the teaching program is terminated. In addition, when there is a weld joint, the robot motion calculation unit 21 sequentially reads the teaching program execution data of the next weld joint and executes each execution data.
[0014]
The route gap calculation unit 22 instructs the robot operation calculation unit 21 to perform a predetermined sensing operation and causes the robot body 1 to perform the gap sensing operation, as described in Japanese Patent Application Laid-Open No. 05-329644, for example. The root gap widths Ws and We on the welding start / end side and the root gap center positions Ps and Pe are calculated from position information in the robot coordinate system based on the detection signal from the cap sensing detection control unit 42 of the apparatus 40. ing.
[0015]
That is, the route gap calculating unit 22 is set to the detection positions P7 and P8 on the surfaces of the grooves 6b and 7b of the left and right welded joint forming members 6 and 7 by the cap sensing operation on the welding start side shown in FIG. From the thickness t of the left welded joint 6 and the grooves 6b, 7b angles θ1, θ2, the root face position information Ps1 (XPs1, YPS1, ZPs1), Ps2 (XPs2, YPS2, ZPs2) of the left and right grooves 6b, 7b And the route gap width Ws in the Y direction (see FIG. 2B) is calculated from the Y-axis position information (YPS1, YPS2) of both the route face portion position information Ps1, Ps2. The route gap calculation unit 22 also divides the Y-axis position information (YPS1, YPS2) of the route face position information Ps1, Ps2 into equal parts (YPS1-YPS2 / 2), and the route gap center position Ps (XPs, YPS, ZPs). ) Is calculated. Similarly, the route gap calculation unit 22 calculates the route gap width Ws on the welding start side and the route gap center position Pe (XPe, YPe, ZPe).
[0016]
The weld joint inclination calculation unit 23 calculates the inclination angle [K] of the weld joint in the weld longitudinal direction X (see FIG. 2 (a)) from both the root gap center position information Ps and Pe calculated by the route gap calculation unit 22. The calculation is performed according to equation (1).
[K] = (ZPe-ZPs) / SQRT ((XPe-XPs) ↑ 2 + 2 + (YPe-YPs) ↑ 2 +
(ZPe-ZPs) ↑ 2 (1)
Further, the weld joint inclination calculation unit 23 is within the allowable value of the calculated weld joint inclination angle [K] and the allowable inclination angle [Ks] set by the allowable weld joint inclination setting unit 44 of the control device 40 described later. It comes to judge.
[0017]
The welding condition calculation unit 24 includes, for example, the plate thickness t of the left welded joint component 6 and the groove angles θ1 and θ2 of the grooves 6b and 7b set in the groove condition storage unit 32 of the storage device 30 described later. Calculates the groove cross-sectional area from the root gap width Ws on the welding start side and / or the root gap width We on the welding end side, and matches the groove angle and root gap width range for each weld joint stored by itself. A matching or close one is selected from a welding condition algorithm consisting of an optimum welding pass and welding conditions of each welding pass.
[0018]
The storage device 30 includes a teaching program storage unit 31, a groove condition storage unit 32, and a primary storage unit 33.
[0019]
The teaching program storage unit 31 stores teaching program execution data of each workpiece taught by the operator, and reads the teaching program execution data to the robot operation calculating unit 21 by setting input of the teaching program No. by the operator.
[0020]
The groove condition storage unit 32 stores, for example, the plate thickness t of the joint component 6 (7) of the root gap weld joint 5 and the groove angles θ1 and θ2 of the grooves 6b and 7b that are set and input. Each set value is output to the route gap calculation unit 22 according to a command from the robot operation calculation unit 21.
[0021]
The primary storage unit 33 is configured to temporarily store various data used when performing computations in each computation unit of the computation processing device 20.
[0022]
The control device 40 includes a robot body control unit 41, a gap sensing detection control unit 42, a welding power source control unit 43, and an allowable weld joint inclination setting unit 44.
[0023]
The robot body control unit 41 controls each arm or the like of the robot body 1 in each axis operation or reproduction operation based on a command from the input device 50 or teaching program execution data from the robot operation calculation unit 21.
[0024]
The gap sensing detection control unit 42 is, for example, a welding torch according to a predetermined sensing operation (see FIG. 2B) by the robot body 1, that is, the welding torch 3, as described in Japanese Patent Laid-Open No. 05-329644. 3 detects the contact of the surface 6a of the left weld joint forming member 6 and the detection positions P7, P8 on the surfaces of the grooves 6b, 7b of the left and right weld joint forming members 6, 7 with the wire tip 4a protruding from 3. Yes. The contact of the wire tip 4a is confirmed when the sensing voltage applied to the workpiece and the welding torch 3 from the sensing power supply (not shown) of the welding power supply 2 becomes substantially zero volts. .
[0025]
The welding power source control unit 43 receives welding start / end commands, welding voltage / current welding condition commands, and the like from the welding program 2 based on the teaching program execution data, and supplies the welding power of the welding condition commands to the welding torch 3 and the workpiece. It is supposed to be. Further, the welding power source control unit 43 is configured to output the welding condition of each welding pass of the optimum welding path selected by the welding condition calculation unit 24 to the welding power source 2.
[0026]
The allowable weld joint inclination setting unit 44 outputs ± 5 degrees of an allowable inclination angle [Ks] set in advance by a command from the robot operation calculation unit 21 to the weld joint inclination calculation unit 23. The reason for setting this allowable inclination angle [Ks] is that, when the welding end side Pe is inclined +5 degrees or more with respect to the welding start side Ps and the up welding is performed, the welding progresses with the molten pool being biased behind the arc. Although the arc is deflected backward, the penetration of the weld pool becomes deeper due to the arc heat and the heat quantity of the molten pool, etc., but the weld bead becomes a convex beat and the molten pool does not conform to both the grooves 6b and 7b, resulting in insufficient penetration. Will do. On the other hand, when the welding is inclined down by -5 degrees or more, the welding progresses in a state where the molten pool is biased in front of the arc, and the arc is deflected forward, so that the welding bead is flattened due to the arc heat, the amount of heat of the molten pool, etc. Although it becomes a tendency concave beat and adjusts to both the grooves 6b and 7b, an arc force is also added in the longitudinal direction of welding and the weld pool is advanced, so that the weld bead is insufficiently penetrated.
[0027]
The input device 50 is, for example, a teaching pendant. With this input device 50, the operator can input the motion of each arm of the robot body 1 in each axis, and can teach the teaching operation of each workpiece. The input program 50 is used to set and input a teaching program number and the like by the operator.
[0028]
Next, an automatic operation method of the welding robot having such a configuration will be described.
[0029]
First, a work composed 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 from the input device 50 by the operator and is activated (S1).
[0030]
Then, the teaching program execution data of the teaching program No set by the robot operation calculation unit 21 is sequentially read out from the teaching program storage unit 31, and the robot body 1 is reproduced in the order based on the teaching program execution data via the robot body control unit 41. Operate (execute) (S2).
[0031]
Execution of the teaching program proceeds, and the robot body 1 is caused to perform a predetermined sensing operation from the route gap calculation unit 22 via the robot operation calculation unit 21 based on gap sensing execution data on the welding start side of the route gap weld joint 5 (S3). The individual position information in the robot coordinate system based on the detection signal from the gap sensing detection control unit 42, and the thickness of the joint component 6 (7) of the route gap weld joint 5 input from the groove condition storage unit 32 The root gap width Ws on the welding start side is calculated from t and the groove angles θ1 and θ2 of the grooves 6b and 7b (S4), and the root gap center position Ps is calculated from the calculated root gap width Ws (S5). ), And stores both calculated values in the primary storage unit 33.
[0032]
Subsequently, the robot body 1 is caused to perform a predetermined sensing operation in the same manner based on the gap sensing execution data on the welding end side of the root gap welded joint 5 (S6), and the robot coordinates based on the detection signal from the gap sensing detection control unit 42. The individual position information in the system, the plate thickness t of the joint constituent member 6 (7) of the root gap weld joint 5 inputted from the groove condition storage unit 32 , and the groove angles θ1, θ2 of the grooves 6b, 7b Then, the root gap width We on the welding start side is calculated (S7), the root gap center position Pe is calculated from the calculated root gap width We (S8), and both calculated values are stored in the primary storage unit 33.
[0033]
Then, the weld joint inclination calculation unit 23 calculates the weld joint inclination angle [K] in the longitudinal direction X of the weld (see FIG. 2 (a)) based on the root gap center positions Ps and Pe read from the primary storage unit 33. (S9) It is determined whether the inclination of the root gap welded joint 5 is within an allowable range based on the calculated inclination angle [K] of the welded joint and the allowable inclination angle [Ks] input from the allowable weld joint inclination setting unit 44. (S10).
[0034]
As a result of the determination, when the inclination of the root gap welded joint 5 is within the allowable range (Yes), the welding condition calculation unit 24 calculates the groove cross-sectional area of the root gap welded joint 5 and calculates the calculated root gap welded joint 5. The optimum welding pass and welding conditions for each welding pass are selected from the groove cross-sectional area (S11), and the optimum welding condition for the welding power source 2 is selected via the welding power source control unit 43 in response to a command from the robot operation calculation unit 21. In addition to the output, welding of the root gap welded joint 5 is performed by the welding power supplied to the welding torch 3 and the workpiece in accordance with the regeneration operation of the welding torch 3 to the root gap welded joint 5 by the robot body 1 (12). ). As a result, the optimum number of welding passes is selected in accordance with the change in the groove cross-sectional area of the root gap welded joint 5, and each weld pass is welded under the optimum welding conditions so that a defect-free route gap welded joint is obtained. Can be formed. It progresses to step S13 which confirms the presence or absence of the next welding joint after completion | finish of welding.
[0035]
On the other hand, when the inclination of the root gap welded joint 5 is outside the allowable range (No), the robot operation calculation unit 21 confirms the presence / absence of the next welded joint from the teaching program execution data (S13), and there is no next welded joint. (Yes), this teaching program execution data is ended, and the welding operation is ended. By this, 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 repair process is not required, and the final root gap welded joint 5 is formed. In the next welding repair process, it is not necessary to perform groove forming work using a glider or the like following gouging cutting, and repair welding with a normal groove is possible, so that repair welding work for repair welding workers can be reduced.
[0036]
However, if there is a next welded joint (No), the robot operation calculation unit 21 continues to move to the next welded joint (S14), and if there is teaching program execution data at the next welded joint, the welding start side Execute gap sensing at. As a result, after the welding operation of this workpiece is completed, the unwelded root gap welded joint 5 is repaired with a normal groove without the need for a groove forming operation by a grinder or the like following gouging cutting in the next welding repair process. Welding is possible and repair welding work for repair welding workers can be reduced.
[0037]
In the automatic operation method of the welding robot in the above-described embodiment, the root gap sensing of the root gap welded joint 5 uses a touch sensor function, but the groove cross-sectional area at the sensing position and both root gap widths Ws, Any method other than the touch sensor function may be used as long as the calculation position information of We can be obtained. Further, when the sensing position is not limited to the welding start / end sides Ps and Pe, and the variation of the root face portion due to individual differences in workpieces and assembly errors is the same, for example, the root face portion extends from the welding start side Ps to the welding longitudinal direction. When expanding toward the approximate center of the direction and then reducing toward the welding end side Pe, in addition to the welding start / end sides Ps and Pe, the sensing position may be set to the approximate center in the welding longitudinal direction. is necessary.
[0038]
In addition, the welding robot in the above-described embodiment includes a positioner that positions a workpiece in a welding posture within the operation range of the robot body 1, and a moving device and a vertical elevating device of the robot body 1 that expands the operation range of the robot body 1. May be provided.
[0039]
Further, instead of the input device 50 in the above-described embodiment, an off-line teaching device using a personal computer such as a computer may be used.
[0040]
【The invention's effect】
As described above, the invention of claim 1 is directed to the downward welding of a welded joint having a straight weld line and an upward or downward inclination with respect to a horizontal plane. The groove shape data of at least two welded joints on the welding start side and the welding end side are taken in the longitudinal direction, and the welding longitudinal direction is based on the root gap center position information calculated from the groove shape data of these welded joints. A horizontal straight line formed by projecting a straight line connecting at least two root gap center positions on the welding start side and the welding end side onto a horizontal plane including the root gap center position on the welding start side, and a welding longitudinal direction. at least the welding start side and said the straight line connecting the root gap center position of the two positions of the welding end side, in the formed are on the route gap As the inclination angle of the direction, the inclination of the welded joint is calculated. If the calculated inclination of the welded joint is within the allowable range, welding is performed under appropriate welding conditions based on the groove sectional area calculated from the groove shape data. If the weld joint tilt is outside the allowable range, the process proceeds to the next weld joint.If the weld joint tilt calculated from the groove shape data is outside the allowable tilt, the process proceeds to the next weld joint. As a result, it is possible to prevent the formation of welded joints that cause poor welding, and since welded joints with an inclination of the welded joint that is outside the allowable range are not welded, gliders etc. following gouging cutting in the next welding repair process This eliminates the need for groove forming work, and enables repair welding with a normal groove, reducing the repair welding work of repair welders.
According to a second aspect of the present invention, the route gap center position information is formed by projecting a straight line connecting the two root gap center positions on the welding start side and the welding end side in the welding longitudinal direction onto a horizontal plane. X direction is a horizontal direction to be performed, a Y direction is a horizontal direction formed by projecting a straight line in a width direction of a route gap for performing the sensing operation on a horizontal plane, and a vertical direction of the root gap for performing the sensing operation is a Z direction. By the sensing operation, the groove shape data of the weld joint at the two weld start sides and the weld end side in the longitudinal direction of the weld are taken in, and the root gap center position Ps (XPs, YPs, ZPs) of the weld joint on the weld start side And a root gap center position Pe (XPe, YPe, ZPe) of the weld joint on the welding end side, and the inclination of the weld joint is calculated by the following formula: The calculation of the tilt of the weld joint can be realized.
(ZPe−ZPs) / SQRT ((XPe−XPs) ↑ 2 +＋ (YPe−YPs) ↑ 2 + (ZPe−ZPs) ↑ 2)
[Brief description of the drawings]
FIG. 1 is a control block diagram of a welding robot according to an embodiment of the present invention.
2A and 2B are weld joint diagrams in the embodiment, in which FIG. 2A is an oblique projection view, and FIG. 2B is an explanatory diagram of a gap sensing operation at a welding start side position;
FIG. 3 is also a flow chart for explaining an automatic operation method of the welding robot in the embodiment.
[Explanation of symbols]
1 Robot body 5 Welded joint (Root gap welded joint)
21 Robot Operation Calculation Unit 22 Route Gap Calculation Unit 23 Weld Joint Inclination Calculation Unit 24 Welding Condition Calculation Unit
X welding longitudinal direction

Claims (2)

In the downward welding of a welded joint that has a straight weld line and has an upward or downward inclination with respect to the horizontal plane, at least two locations on the welding longitudinal direction, that is, at the welding start side and at the welding end side, by sensing operation before the welding is performed. The groove shape data of the welded joints of the welding joints are taken in, and based on the root gap center position information calculated from the groove shape data of these welded joints, at least two locations on the welding start side and the welding end side in the longitudinal direction of welding A horizontal straight line formed by projecting a straight line connecting the center positions of the root gaps onto a horizontal plane including the root gap center position on the welding start side, and at least the welding start side and the welding end side in the welding longitudinal direction. and the straight line connecting the root gap center position of the point, in the inclination angle of the root gap vertically formed, Starring the inclination of the weld joint If the calculated inclination of the welded joint is within the allowable range, welding is performed under appropriate welding conditions based on the groove cross-sectional area calculated from the groove shape data, and the inclination of the welded joint is within the allowable range. An automatic operation method for a welding robot, wherein if it is outside, the process moves to the next welded joint. The route gap center position information is a horizontal direction formed by projecting a straight line connecting the two route gap center positions on the welding start side and the welding end side in the welding longitudinal direction to the horizontal plane in the X direction, The horizontal direction formed by projecting a straight line in the width direction of the root gap for performing the sensing operation onto the horizontal plane is defined as the Y direction, and the vertical direction of the root gap for performing the sensing operation is defined as the Z direction. initiator and takes in the groove shape data of the welded joint of the two positions of welding end side, the welding start side of the welded joint of the root gap center position Ps (XPs, YPs, ZPs) and the root of the welded joint of the welding end side Calculate as gap center position Pe (XPe, YPe, ZPe)
The automatic operation method of the welding robot according to claim 1, wherein the inclination of the weld joint is calculated by the following equation.
(ZPe−ZPs) / SQRT ((XPe−XPs) ↑ 2 +＋ (YPe−YPs) ↑ 2 + (ZPe−ZPs) ↑ 2)

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