JPS60191671A - Method for following weld line in welding robot - Google Patents

Abstract

PURPOSE:To widen the range of applicable work by determining coordinate axes components of the body of a robot of displacement of a torch consisting of fitting angle of a peripheral axis to the body of the robot, and preparing a pattern of oscillation by adding displacement of coordinate axes themselves. CONSTITUTION:The body of the robot RO is placed on a moving body and travels along a peripheral axis T that extends at a fitting angle gamma to X-axis. A computer 10 includes a CPU and a memory and controls whole system. A remote control board 11 is provided with a group of working switches SW, condition setting switches SE etc. The computer 10 performs arc sensing at all times during welding, and corrects positional deviation using data stored beforehand, and at the same time, prepares a pattern of oscillation and outputs it. An executing pattern of oscillation is moved in the direction of groove width at right angles to a teaching weld line and in the direction of height by length of successive correction, and the torch 4 always follows up the weld line. Accordingly, it becomes not necessary to make the weld line parallel to the peripheral axis, and the range of applicable work is widened.

Description

[Detailed description of the invention] The present invention performs arc welding while swinging the welding torch in the width direction of the IA tip, detects a positional deviation of the welding torch during this swinging, and corrects this positional deviation. The present invention relates to a welding line tracking method in a welding robot that aims to dramatically improve welding line tracking performance in a welding robot that causes a welding torch to follow the welding line.

As a method for teaching the above-mentioned swing pattern, there is a method in which the tip of the electrode (welding point) of the welding torch is actually positioned near the groove, and the two end points of the half period of the swing pattern are taught. Patent application filed on March 2, 2017 (
The welding robot proposed under the title of the invention "welding robot" is equipped with a means for creating a swing pattern by inputting numerical values, and can be used at any point (referred to as a dummy point) that is easy to visually and position within the coordinate quadrant including the bevel during teaching. There is a method in which the welding torch is positioned at 1) and the oscillation pattern is taught while the torch remains stationary.

Now, generally, a welding robot has a main body including a welding torch as an end effector installed on the floor, and a workpiece fixture for fixing the workpiece with an appropriate jig is arranged near the main body. The simplest workpiece fixture has a workbench installed on the floor, and it also has various positioners that can move and rotate the workpiece. Things are selected. If the target workpiece is long and slender, and the welding line is therefore very long in one direction and exceeds the movement range of the welding torch, it is necessary to move the robot arm, the workpiece fixture, or both in the direction in which the workpiece extends. Become. Hereinafter, for convenience, the traveling axes and the like that are controlled separately from the main body will be collectively referred to as peripheral axes.

Conventionally, when the above-mentioned swing pattern is taught to a T6 contact robot having the peripheral axis (either manually or automatically), the computer that controls the entire welding robot assumes that the peripheral axis is parallel to the welding line and performs the 'C swing. Create a dynamic pattern. When attaching a workpiece, efforts are made to ensure that the weld line follows the peripheral axis, but the weld line is not necessarily straight; it is common for the weld line to be bent or curved along the way, or in various directions. As shown in Fig. 8 (example of horizontal fillet welding), when the weld line WL is arranged diagonally with respect to the surrounding area 1111IIT, the operator can use the motion pattern of an isosceles triangle with the weld line WL as the base. PT (double-dashed line), and teach both end points a-b of the swing by manual setting. However, in reality, the computer considers the welding line WL to be the peripheral dfl+T, as mentioned above.
Swing pattern PT of an isosceles triangle with the peripheral axis T as the base
'(solid line a-b-c).

Therefore, the oscillation pattern PT that the operator considers to be optimal for welding and the oscillation pattern PT created by the computer differ greatly as the deviation angle △δ between the peripheral axis T and the welding line -vVL increases. It's coming. This means that
The pitch defined as the moving pressure point in the extending direction of the welding line WL during a half cycle or one cycle of oscillation also varies greatly, making it impossible to obtain the optimal welding conditions desired by the operator.

If arc welding is now performed on a workpiece that is exactly the same as the workpiece during teaching, a swing pattern p'r' shown by a dotted line in FIG. 8 will be drawn.

The first swing pattern moves as a - + b - + c according to the 3id movement pattern PT' created by the computer, and since the electrode tip of the welding torch has not yet reached the workpiece W, from then on, the IB electrode tip moves to the workpiece W. c until contact
As shown by −+d, the surrounding li! Move in a direction perpendicular to 1lIT. Then, the computer creates the next pattern starting from point d, and similarly executes the second period of the swing pattern. If the direction in which the correction is applied is perpendicular to the work surface, it can be considered ideal in that the execution swing pattern of the correction stage is close to the teaching M movement pattern, but if the correction is made in the direction perpendicular to the peripheral axis T. is multiplied, so execution i
The J3 movement pattern is △1 (=△Ps
tnΔδ) will flow in the direction of the complete weld line WL, which, together with the discrepancy in the swing patterns described above, will have a negative effect on the welding conditions. Of course, when the welding line WL is inclined to the lower side of the peripheral axis T (in the paper plane of Figure 8), the IJLI pitch and △l
r'rl;i shrinks in the opposite direction to the direction in which the concubine line WL extends, and this also does not result in a swing pattern desired by the operator.

In view of the above-mentioned circumstances, the present invention includes a J,'11 side axis that can control the movement of either or both of the robot body including the welding torch and the workpiece fixture separately from the robot body. , when creating the I pattern, Noi+J
The robot body's coordinate axis component of the welding torch's movement amount is determined from the mounting angle of the side axis with respect to the robot body, and the chisel d movement pattern is created by adding the movement amount of the valley coordinate axis itself to these. ;1・Ill and r
J: 'I' The objective is to provide a 1d tangent tracking method for a welding robot, which is characterized in that it is executed by distributing it to the six coordinate axes, and which improves the followability of the bath tangent.

Hereinafter, a detailed description will be given based on the embodiments shown in the drawings.

1 is a 111 square seat U (X
, Y, Z) are the vertical axes configured at the terminals of the robot RO (details not shown).

2 is a vertical ii'llll. At the end of 1, there is a 1st) corpse Q supported so as to be able to pivot around IPIIll (arrow α).

3 rotates around the oblique axis 3a (arrow β) at the tip of arm 2 rr
It is the second arm supported by J-Noh. 2nd) A Jf torch 4 (an MIG welding torch in this embodiment) as an end effector is attached to the tip of the sluice 3.

The central axes M of the support 1, shaft 3a, and torch 4 are drawn to intersect at one point P.

Further, the torch 4 is set so as to coincide with the welding operating point P thereof. Thus, the rotation angle in the σ and β directions is 1lII11! By controlling Lfl, the attitude angle θ and the turning angle ψ (so-called Euler angle) with respect to the vertical 4J+1 of the torch 4 are kept constant at 1 at point P, resulting in 1νI control 1−1J. The robot RO main body described in No. 1 is placed on a moving body (not shown), and the entire body runs along an axis (hereinafter referred to as peripheral axis T) extending at an installation angle of r with respect to Xl and 1111. It has become something to do.

5 is a four-source welding device d. The device 5 is equipped with a spool 7 that winds up the consumable electrode 6 of the torch 4, and although the mechanism is not shown, the electrode 6 can be drawn out by rotating a feed roller. W
This groove IJ2 is provided so that the power source 8 and the IL sensor 9 (', 7, 7) can be connected in the 1α row.

Reference numeral 10 denotes a known computer as a control device i'i for the entire Mα example. The computer IO has a CPU
8 and memory.

A power source 8 and a current sensor 9 are connected to the path line B of the computer 10.

The servo system SX of XOb of the robot RO is connected to the pass line B, and this servo system SX is XIi'
It includes the power MX1 of the lII and an encoder EX that outputs its position information. Similarly, to the pass line B, connect the Y-axis servo system SY, the Z-axis servo system S21α, the servo system Sα of the Z-axis, the servo system Sβ of β4411, and the T-axis servo system ST. It is.

Reference numeral 11 denotes a remote control panel, which includes a manual operation snap switch group SW for manually moving the torch 4, a speed command rotary switch sV for commanding speeds other than welding standby, and a mode 34f[+i (manual mode M, A mode selector switch SM for switching to test mode TE and mode A), a numeric keypad TK, a condition setting selector switch SE for setting the conditions of m< at each switching position described below by operating the numeric keypad TK, and each It is equipped with a start switch STA, etc., which is used to start operation in the mode and to import teaching contents into memory.

The changeover switch SE has six switching positions shown below.
It has SE r~SE.

(1) Switching position SE, ... linear interpolation "L", weaving "W" 9 inner sleeve gap "C", arc sensing rAsj
It is equipped with four display lamps, and by pressing key numbers "1" to "4" on the numeric keypad TK, each of the six display lamps can be turned on and selected.

(2) Switching position SE, . . . has a display section of welding condition number WNll, and the welding voltage E, welding current 1. and bath contact speed Vw are stored as a set, and can be called up by pressing the key number on the numeric keypad TK corresponding to the desired set.

(3) Switching position sE,...Function number FN [
In this embodiment, by operating the key number "7" on the numeric keypad TK, the current position of the welding torch T is not the teaching point of the movement position (it is teaching that it is a blank point). do.

(4) Switching position SE...has a display section for the sleeve number AUX, and in this embodiment, the key number r of the numeric keypad TK
uu.

By pushing r02J and r03J, the J2 figure (
a).

As shown in (b) and (c), the weld joint shapes of downward fillet, horizontal fillet, and rectangular tip are selected.

In addition, AUX&[10J is an i created in advance in another work.
This means that the position ID is corrected based on the data of the ru a pattern.

(5) Switching position ii'1SE---The pattern display section is set equal, and in this embodiment, the swing pattern is set using a four-digit number. For example, the 4th to 1st digits respectively indicate the amplitude m (movement distance in the groove width direction) of the i:ij movement pattern.

Height h (as shown in Figure 2 (a), (b), and (C), for downward fillets and the tip of the U8 shape, it is the distance from the welding line to the swinging surface, and for horizontal fillets, it is the leg length. ), Bitch P (3rd
As shown in the figure, the distance traveled in the direction in which the welding line extends during each half cycle of the swing pattern).

It is designed to set each menu symbol of increments an ((the number of movement divisions in the half circumference ju1 of the J movement pattern, the frequency is determined by n). In addition, in the case of equal leg length in horizontal fillets, special If you set h1 East to "3", it will automatically become 4-legged.

(6) Switching position fδSE, . . . has a timer display 1) 1, and the stop time at the left and right ends of the swing can be set using a menu number.

The hands and work W are fixed on the floor as shown in Figure 1.
i41 in the T-axis direction on the large workbench WT
2 fi4 vertical member W2 on the top surface of long horizontal member ■1
W3 are combined in a "<" shape and tack-attached, and the right-angled corner formed by these members W1, W2, and W3 is moved from the welding start point P8 at one end to January 11, where members W2 and W3 intersect.
It is assumed that continuous welding is performed from point J to P4 to the welding end point P5 at the other end.

The operator's teaching operation and the processing executed by the computer 10 in connection therewith will be explained below.

(Tl) Manual mode M by operating switch SM.
Select. Then, by operating the switch SW, the torch 4
is positioned at an arbitrary point P close to the welding start point P3. Next, turn off the selector switch SE! 8 position SE, to I
;IJ Kyou, a straight line by operating the numeric keypad TK? Ji l
By setting 1iJ r L J and operating the switch 5TAe, the computer 10 will obtain the position information 4 (X,.

View, Zl, θ1. and ψI) and linear interpolation "L" as the first step.

(T2) Position the torch 4 at the welding starting point P in a posture suitable for welding by operating switch y-8W.

Next, the arc sensing rAsJ is set by operating the numeric keypad TK while the switching position of the changeover switch SH remains unchanged, and the computer 5 is set to point P by operating the switch STA.
The next step is to take in the position information of , and the arcsen sink AsJ.

(T3) The torch 4 is moved to the member W1 by operating the switch SW.
- Any point P within the coordinate quadrant surrounded by W2 and W3.

(referred to as one dummy point).

Next, the selector switch SH is turned off at position fδSE, s'14,
S.E.

rA by operating the numeric keypad TK in SE and
Set sj, r7J, r02J. Of these, FN
cir7J is a single dummy designation, and AUXNa r(
12'' is the designation of a horizontal fillet as the weld joint shape (see Figure 2).

Furthermore, at the switching position SEg of the changeover switch SE, the vibration +? :+
'+ m, height, pitch P, and number of increments n are set using a 4-digit menu μ value. After that, by operating the switch STA, the computer IO will display the position information of the dummy point P3, the arc sensing rAsj, FFh r7J,
ALIXNar02j and 1-8 movement pattern'I
The 8th report will be taken in as the next step.

(T4) By operating the switch SW, the torch 4 is positioned at the intermediate point P4 in a posture ready for welding.

Next, the switching positions SE, , SE,
.

At SE, SE, set rksJ, rold, J, rlOJ, and rlJ by operating the tincture-TK, respectively. Among these, WNQ "01" is the menu number 1 having the optimum welding conditions (welding voltage, welding current, etc.) from the welding start point P1 to the intermediate point P.

Furthermore, AUXlkrlOj means that the position fif =++ is corrected using swing pattern data obtained in advance from another workpiece. Further, the timer "1" specifies a menu number suitable for temporarily stopping the welding torch 4 at the left and right ends of the swing. Now, by operating switch STA, computer 0 will receive the position information of intermediate point P4, arc sensing rAs J, WNQ rolJ, AUXNI r
lt)j, capture timer "1" as next step.

("r5) By operating the switch SW, the torch 4 is positioned at the welding end point P6 in a posture suitable for welding.

Then, by switching the selector switch SE and operating the numeric keypad TK O), set exactly the same as (T4), and set the switch/7chi ST.
If there is a deviation in the operation of A, the computer 10 will set the welding end point P,
(7) place 1lt1!7I4i, 7-kusenshi:/ )/
rAsj, W1%r+11j, AUX tooth rlOj
, timer ``Fetch Ll as next step.''

(T6) By operating the switch SW, the torch 4 is positioned 1δ at an arbitrary retreat point P6 that can be moved linearly from the welding end point P5. Then switch the selector switch SE to position S.
Switch to E, and use the numeric keypad 'rK to set straight line 0 old f.
(] If you set rLJ and operate switch STA,
The computer 10 calculates the position information of point P and linear interpolation rLJ.
as the next step.

This completes the teaching. FIG. 4 shows 85f' of the series of user programs described above.

Next, when the operator sets switch SM to test mode °rE and operates switch ST, each step of the 1jil program will be executed (however, welding will not be performed but will be repeated, and if there is an error, it will be corrected. 2" 0) The execution J4 movement pattern will be described later.

Next, switch SM is set to auto mode A, and switch S is set to auto mode A.
When the TA is operated, the aforementioned programs are executed continuously. The flow of processing executed by the computer IO in case of C will be explained with reference to the flowchart of FIG.

(A1) The computer 10 determines whether or not there is a command rAsJ in a step of the user program (processing PR
I).

(A2) If there is no command rAsJ, V at this step]
(processing PR2).

(83) If there is a command rAsJ in the process PRI, it is further determined whether the peripheral axis T is included (process PR3).

(A4) If the peripheral iin, h T is included, the vector of the movement amount is calculated from the mounting angle of the peripheral axis T (in this case, the mounting angle r formed by the peripheral shaft T with respect to the X tank), and this is calculated as X.

Converting into Y and Z axis components, the movements of the robot body's X, Y, and Z axes, respectively! II! Add 1Mk Ic (processing PR4).

(A5) Determine whether the current position is an intermediate point.

(Processing PR5) (A6) If it is not the intermediate point, it is further determined whether automatic setting is required (Processing PR6).

(A7) In process PR6, if FNa is "7", it is judged as automatic setting, and based on the information taught to the dummy point P, create a swing pattern of arc weaving from 48 m + f m, height, and pitch P. (Processing PR7
).

(A8) In process PR6, if FN[L is "7", it is determined that it is a manual setting, and the explanation is omitted here, but the welding torch 1 is actually positioned at the groove and oscillates as taught. A pattern is created (processing PR8).

(A9) If the current position is the intermediate point in process PR5, perform rotation correction on the pattern created in the previous process P'R7 so that it follows the new weld line, and create a new /(turn (process PR9).

(Alυ) When each of the processes PR7, PH8, and PH1 is completed, it is again determined whether the peripheral axis f is included (process PRIO).

(All) If the surrounding area 1111T is included, the above processing PR4
Conversely, the created swing pattern is distributed to the peripheral axis T and the x, y, and z axes of the robot body (processing PRII).

(A12) Execute the arc sensor using the created pattern (processing PR12).

(A13) Determine whether the step has reached the end (processing PR13).

(A14) If it is the end, the series of execution in the auto mode ends, but if not, the step is updated and the process returns to the previous step PR14).

Accordingly, the drive section of the welding robot R'0 main body and the peripheral axis T performs the following operations based on the command output from the computer 10. First, the torch 4 is positioned at a point P1, and the torch 4 is moved toward the welding start point P by linear interpolation.

When the torch 4 reaches point P, it starts arc weaving, and as the robot RO body moves along the peripheral axis T1, horizontal fillet welding is performed toward point P4 based on welding conditions 14r01j. Then, the computer 10 performs arc sensing during welding, corrects the positional deviation using data A[NarlOJ stored in advance, and then creates and outputs a swing pattern by the process PR7. That is, as shown by the solid line in FIG. 6, the execution swing pattern PT' is a groove perpendicular to the welding line of the workpiece W subjected to teaching (not the welding line WL' of the workpiece W to be welded) by the amount of sequential correction. The torch 4 is moved in parallel in the width direction and the height direction, so that the torch 4 always follows the welding line. Note that the workpiece W indicated by the dotted line in FIG. 6 is used for teaching, and the dotted line indicates the swing pattern PT drawn in the test mode (welding is not performed).
It can be seen that the weld line WL is followed even in the test mode.

Next, the torch 4 is set to medium+i [when it reaches point P4, the process PR
7) With the new swing pattern created from this, the direction is changed from the intermediate point P4 to the welding end point P, and the above-mentioned P, →
P4! Arc weaving is performed in the same way as fXl welding. 4tl l,, the posture of torch 4 is at point p,, p,
.

P, dete, ``- Gradually convert to the Ching Shida posture.

When the torch 4 reaches the welding end point P, it finishes welding and moves in a straight line to the retreat point P6.

In addition to the above-mentioned embodiments, the present invention can also be modified as described below.

(1) In the above embodiment, the position correction by arc sensing is created in advance and the data (AUX4rlOJ
), however, sampling data may be created at the beginning of welding execution and position oil stoppage may be performed based on that data.

(i >+'+il In the embodiment described above, the robot body was made to travel along the peripheral axis T, but the workbench WT may be moved along the axis T, or both may be made to travel together. .

(IiT) The number of peripheral axes is not limited to one, but may be multiple, and these can also include rotational axes. For example, as shown in FIG. 7, if a rotating axis T3 is provided that is parallel to the axis 61+ and the axis T, a screw-like blade wb is arranged in an arc on the outer surface of the circular body 14. Continuous welding of horizontal fillets is possible while sensing.

(1v) The peripheral axis does not have to coincide with any of the coordinate axes of the robot body, and can be set arbitrarily as long as one mounting angle with respect to the coordinate axes of the robot body is made clear.

As detailed above, the present invention provides the following unique and remarkable effects.

(b) Calculate the vector of the amount of movement from the mounting angle of the peripheral axis, convert it into x, y, and z axis components, and create a swing pattern by adding them to the x, y, and z axes on the robot body side, respectively. Therefore, for example, if a swing pattern of an isosceles triangle with the welding line as the base is optimal, a swing pattern (turn) is created in this case, and when executed, the swing pattern is reversed to X, Since it is divided into Y, Zl! II and peripheral rings, arc weaving can be performed in the desired 4 (7n) movement pattern suitable for the workpiece, and the welding line tracking performance is greatly improved.

(b) As is clear from the reasons in +iii (a),
Since the Idi movement < turn is created based on the welding line rather than the surrounding area +1-tit, even in test mode it forms an oscillation pattern along the welding point A and checks various conditions. -Easy to modify.

(c) Since the correction direction is not perpendicular to the peripheral axis as in the conventional case, but perpendicular to the weld line of the workpiece during teaching, the followability of the weld line is improved.

(d) The correction range uses the welding line of the workpiece during teaching, not the peripheral axis, as the reference, so no matter how oblique the welding line is to the peripheral axis, this will not be correct! 1 (relationship). Therefore, the correction range 1 and the 4171 body differences of the workpiece only need to be within this range, which is actually wider than the conventional case where the deviation angle of the weld line with respect to the peripheral axis is included.

(e) As can be seen from (d) above, since the weld line does not need to be aligned with the peripheral axis, arc sensing is possible even with freely bent or curved weld lines, greatly expanding the range of applicable workpieces.

[Brief explanation of drawings]

1 to 7 show an embodiment of the present invention, and FIG. 8 shows a conventional example. Of these, FIG. 1 is an overall view of the welding robot of the present invention, and FIG. 2 is a schematic diagram showing various welding joint shapes. Figure 3 is an explanatory diagram of the swing pattern, Figure 4 is a step diagram of the program,
FIG. 5 is a flowchart, FIG. 6 is an explanatory diagram showing the formation of a rocking pattern in test mode and auto mode, and FIG. 7 is a perspective view showing an example in which a running axis and a rotating axis are included as peripheral axes. , FIG. 8 is an explanatory diagram of a conventional rocking pattern. In the figure, RO is a robot, 4 is a welding torch, 10 is a computer, 11 is a remote working machine, and W is a workpiece. Applicant ShinMaywa Industries Co., Ltd.

Claims (2)

[Claims] (1) Arc welding is performed while the welding torch is oscillated in the 111 width direction, the positional deviation of the welding torch is detected during the oscillation, and the welding torch is made to follow the welding line by correcting this positional deviation. In a welding robot that
(nil) A robot body including a welding torch and a peripheral axis that can control the movement of one or both of a workpiece fixture separately from the robot body, and when creating a swing pattern,
The coordinate axis components of the robot body of the amount of movement of the welding torch are determined from the mounting angle of the peripheral axis with respect to the robot body, and the amount of movement of each coordinate axis itself is added to these to create an oscillation pattern. 1. A welding line tracking method in a welding robot, characterized in that the welding line tracking method is performed by distributing it to an axis and a coordinate axis. (2) The welding line tracking method in a welding robot according to claim 1, wherein the peripheral axis includes at least one of a traveling axis and one rotating axis in one direction.