JP2019028909A - Welding robot apparatus - Google Patents

Abstract

To enable a spiral trajectory to be described as a user demands, while restricting vibration during spiral weaving operation.SOLUTION: A spiral radius for a spiral weaving operation, a spiral frequency, a plurality of welding conditions are input to an input unit 12. In a selection unit 13, a selection is made to determine whether to exert vibration restriction control in which vibration of a welding torch 21 is restricted. In a case where a selection is made so as to exert vibration restriction control, a spiral radius re-calculation unit 16 re-calculates a new spiral radius on the basis of a spiral frequency input by the input unit 12. On the basis of the re-calculated new spiral radius, a robot control apparatus 11 controls a multi-joint welding robot 20 so as to perform a spiral weaving operation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a welding robot apparatus.

  2. Description of the Related Art Conventionally, there has been known an arc weaving (spiral weaving) control method for controlling arc movement while weaving the tip of a welding torch attached to the wrist of an industrial robot (see, for example, Patent Document 1).

  By the way, when performing spiral weaving, it is necessary to set a spiral radius and a spiral frequency as parameters for determining the operation locus. As shown in FIG. 7, the spiral radius is the amplitude with respect to the traveling direction of the spiral trajectory. Further, the position of the welding torch during the helical weaving operation can be represented by a helical angle that is an angle from the helical center.

  Here, the amount of change in the helix angle is determined by the helix frequency. For example, if it takes 1 second for the helix angle to change from 0 ° to 360 °, the helix frequency is 1 Hz. Therefore, the higher the spiral frequency, the greater the number of revolutions of the spiral weaving trajectory.

Japanese Patent Laid-Open No. 61-15208

  By the way, during the spiral weaving operation, depending on the teaching posture, the tip of the welding torch vibrates with a sudden posture change, and it may be difficult to perform normal welding. In order to suppress the vibration, it is conceivable to smooth the posture change by filtering the robot posture control signal.

  However, when a gentle posture change is performed with the helical frequency as it is, there is a problem that only a spiral locus having an amplitude smaller than a predetermined helical radius can be drawn as shown in FIG.

  The present invention has been made in view of this point, and an object of the present invention is to be able to draw a spiral locus as desired by the user while suppressing vibration during the spiral weaving operation.

  The present invention is directed to a welding robot apparatus including an articulated welding robot having a welding torch at the tip, and has taken the following solutions.

That is, the first invention is a robot control device for controlling the articulated welding robot so as to perform a helical weaving operation for welding while drawing a predetermined helical trajectory,
An input unit capable of inputting a spiral radius, a spiral frequency, and a plurality of welding conditions for performing the spiral weaving operation;
A selection unit for selecting whether to perform vibration suppression control that suppresses vibration of the welding torch;
A helical radius recalculation unit that recalculates the helical radius based on the helical frequency input at the input unit;
The robot control device performs the spiral weaving operation based on the new spiral radius recalculated by the spiral radius recalculation unit when the selection unit is selected to perform the vibration suppression control. As described above, the articulated welding robot is controlled.

  In the first invention, the normal spiral weaving operation is performed based on the spiral radius input at the input unit. On the other hand, when the spiral weaving operation is performed while suppressing the vibration of the welding torch, the spiral radius is recalculated based on the spiral frequency input at the input section, and the spiral weaving operation is performed based on the new spiral radius. Is called.

  Thereby, a predetermined spiral radius can be ensured while suppressing vibration during spiral weaving welding.

  Specifically, during vibration suppression control, for example, based on a spiral radius magnification table in which the magnification is determined by the spiral frequency, the spiral radius is doubled according to the input spiral frequency, and the new spiral radius is recalculated. A predetermined spiral radius can be secured by performing the spiral weaving operation based on the new spiral radius.

  According to the present invention, it is possible to draw a spiral locus as desired by the user while suppressing vibration during the spiral weaving operation.

It is the schematic which shows the structure of the welding robot apparatus which concerns on this embodiment. It is the schematic when the 1st and 2nd board | plate material is helical weaving welding. It is the schematic for demonstrating the switching angle of welding conditions. It is a figure which shows the magnification table of a spiral radius recalculation part. It is the schematic for demonstrating the delay of the switching timing at the time of vibration suppression. It is a figure which shows the angle table of a welding condition switching angle recalculation part. It is the schematic for demonstrating a helix radius and a helix angle. It is the schematic for comparing an original helical locus | trajectory with the helical locus | trajectory at the time of vibration suppression.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

  As shown in FIG. 1, the welding robot apparatus 10 includes an articulated welding robot 20, a robot control apparatus 11, and a welding control apparatus 15.

  The multi-joint welding robot 20 is a multi-axis robot having a plurality of servo motors 23. A welding torch 21 and a wire feeder (not shown) are attached to the tip of the robot arm 22. The articulated welding robot 20 can perform a so-called helical weaving operation in which welding is performed while moving the welding torch 21 so as to draw a predetermined helical trajectory.

  The robot control device 11 includes a control unit 14, and the operation of the articulated welding robot 20 is controlled by a control signal output from the control unit 14. The control unit 14 includes a spiral radius recalculation unit 16 and a welding condition switching angle recalculation unit 17 which will be described later.

  The robot control device 11 is provided with an input unit 12 and a selection unit 13. The input unit 12 is composed of, for example, a touch panel monitor. The user can input a spiral radius, a spiral frequency, a welding condition switching angle, a welding condition, and the like, which are parameters for performing the spiral weaving operation, by operating the input unit 12.

  The selection unit 13 includes, for example, a switch, a touch panel monitor, and the like. The user can arbitrarily select whether or not to perform vibration suppression control that suppresses vibration of the welding torch 21 by operating the selection unit 13. Instead of providing the input unit 12 and the selection unit 13 separately, for example, the input unit 12 may be configured by a touch panel monitor and an icon indicating the selection unit 13 may be displayed on the monitor screen of the input unit 12. Good.

  Hereinafter, a case where a first plate 31 having a thickness t1 and a second plate 32 having a thickness t2 (> t1) larger than the first plate 31 are welded as illustrated in FIG. .

  Specifically, the peripheral portions of the first plate member 31 and the second plate member 32 are abutted, and the welding torch 21 is welded while performing a spiral weaving operation so as to straddle the first plate member 31 and the second plate member 32. I do.

  In the example shown in FIG. 2, the spiral center passes through the abutting portion between the first plate member 31 and the second plate member 32, and the welding torch 21 proceeds in the direction from the left to the right in FIG. 2. Then, a spiral weaving operation is performed based on the spiral radius and the spiral frequency input by the input unit 12.

  Here, in performing spiral weaving welding, welding is performed while supplying a larger current to the second plate member 32 having a larger plate thickness than the first plate member 31 than when the first plate member 31 is welded. As is done, the welding conditions are switched.

  Specifically, as shown in FIG. 3, the welding torch 21 is positioned on the first plate 31 side, and the spiral angle is in the range of 0 ° to + 180 ° (the range not hatched in FIG. 3). Then, the welding condition α is set so that welding is performed by supplying a predetermined current.

  On the other hand, when the welding torch 21 is located on the second plate member 32 side and the helix angle is in the range of 0 ° to −180 ° (the hatched range in FIG. 3), it is larger than the welding condition α. The welding condition β is set so that welding is performed while supplying current. The supplied voltage may be changed according to the welding condition α and the welding condition β.

  Thus, in the example shown in FIG. 3, when the switching angles A and B are 0 ° and 180 °, the welding conditions are switched. That is, the articulated welding robot 20 performs low pulse welding by switching the welding conditions A and B when the helical angle reaches the welding condition switching angle.

  By the way, during the spiral weaving operation, depending on the teaching posture, the tip of the welding torch 21 may vibrate with a sudden posture change, and it may be difficult to perform normal welding.

  Therefore, in the present embodiment, whether or not to perform vibration suppression control that suppresses vibration of the welding torch 21 can be arbitrarily selected by the selection unit 13. When performing vibration suppression control, the spiral radius and the welding condition switching angle are recalculated using the spiral radius recalculating unit 16 and the welding condition switching angle recalculating unit 17.

  Specifically, when the vibration of the spiral weaving is suppressed, the spiral radius is smaller than the original locus (see FIG. 8). How small it is depends on the helix frequency.

  The spiral radius recalculator 16 has a magnification table 16a (see FIG. 4). The magnification table 16a is a table in which magnifications necessary for returning to the original helical radius are calculated in advance for each constant helical frequency (for example, 0.5 Hz), and are tabulated.

  When performing vibration suppression control, the spiral radius recalculation unit 16 determines the corresponding magnification in the magnification table 16 a from the spiral frequency input at the input unit 12, and with respect to the spiral radius input at the input unit 12. The new helical radius is recalculated by multiplying the magnification determined from the magnification table 16a.

  Here, the spiral frequency of the magnification table 16 a includes the minimum value and the maximum value of the spiral frequency that can be input by the input unit 12. If there is no table that matches the helical frequency input from the input unit 12, the magnification is determined by linear interpolation from the preceding and following table values.

  The multi-joint welding robot 20 performs a spiral weaving operation using the recalculated new spiral radius. At this time, the multi-joint welding robot 20 tries to execute the spiral weaving with a radius larger than the spiral radius input by the user, but the spiral radius becomes small by the vibration suppression control, and as a result, the user does not specify. Spiral weaving can be performed with a radius.

  Further, when the vibration of the spiral weaving is suppressed, the welding condition switching angle is delayed from the original switching angle as shown in FIG. The delay is determined by the helical frequency.

  The welding condition switching angle recalculation unit 17 has an angle table 17a (see FIG. 6). The angle table 17a is a table in which angles necessary for returning to the original welding condition switching angle are calculated in advance for each constant helical frequency (for example, 0.5 Hz).

  When performing vibration suppression control, the welding condition switching angle recalculation unit 17 determines the corresponding angle of the angle table 17a from the helical frequency input by the input unit 12, and switches the welding condition switching input by the input unit 12. The welding condition switching angles A ′ and B ′ are recalculated by adding or subtracting the angles determined from the angle table 17a to the angles A and B. Whether to add or subtract the angle determined from the angle table 17a is determined by the rotation direction of the spiral trajectory.

  Here, the helical frequency of the angle table 17 a includes the minimum value and the maximum value of the helical frequency that can be input by the input unit 12. If there is no table that matches the helical frequency input from the input unit 12, the angle is determined by linear interpolation from the preceding and following table values.

  Further, the spiral angle has a lower limit and an upper limit (for example, −180 ° to + 180 °). The welding condition switching angle recalculation unit 17 has a function of adjusting so that the welding condition switching angle after recalculation falls below the lower limit or exceeds the upper limit so that the welding condition switching angle is within the lower limit and the upper limit.

  The multi-joint welding robot 20 performs a spiral weaving operation using the recalculated new welding condition switching angles A ′ and B ′.

  As described above, according to the welding robot apparatus 10 according to the present embodiment, the spiral trajectory having the spiral radius and the welding condition switching angle as input by the user through the input unit 12 while suppressing the vibration of the welding torch 21. We can perform welding while drawing.

  As described above, the present invention is extremely useful and industrial because it provides a highly practical effect of being able to draw the spiral trajectory desired by the user while suppressing vibration during the spiral weaving operation. The availability of is high.

DESCRIPTION OF SYMBOLS 10 Welding robot apparatus 11 Robot control apparatus 12 Input part 13 Selection part 16 Helical radius recalculation part 17 Welding condition switching angle recalculation part 20 Articulated welding robot 23 Welding torch

Claims (4)

A welding robot apparatus including an articulated welding robot provided with a welding torch at the tip,
A robot controller for controlling the articulated welding robot so as to perform a helical weaving operation of welding while drawing a predetermined helical locus;
An input unit capable of inputting a spiral radius, a spiral frequency, and a plurality of welding conditions for performing the spiral weaving operation;
A selection unit for selecting whether to perform vibration suppression control for suppressing vibration of the welding torch;
A helical radius recalculation unit that recalculates the helical radius based on the helical frequency input at the input unit;
The robot control device performs the spiral weaving operation based on the new spiral radius recalculated by the spiral radius recalculation unit when the selection unit is selected to perform the vibration suppression control. A welding robot apparatus that controls the articulated welding robot as described above. In claim 1,
The input unit is configured to be able to input a welding condition switching angle for switching the welding conditions,
A welding condition switching angle recalculation unit that recalculates the welding condition switching angle based on the helical frequency input in the input unit;
The robot control device switches the welding condition when the welding condition switching angle is reached during the spiral weaving operation, while the welding condition is selected by the selection unit to perform the vibration suppression control. A welding robot apparatus, wherein the welding condition is switched based on the new welding condition switching angle recalculated by the switching angle recalculation unit. In claim 1 or 2,
The spiral radius recalculation unit is configured to recalculate a new spiral radius when performing the vibration suppression control by multiplying the spiral radius input by the input unit by a predetermined magnification. Welding robot device characterized by that. In claim 2,
The welding condition switching angle recalculation unit adds or subtracts a predetermined angle with respect to the welding condition switching angle input by the input unit, thereby performing a new welding condition switching angle when performing the vibration suppression control. A welding robot apparatus configured to recalculate

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