JPS5985376A - Arc welding robot - Google Patents

Abstract

PURPOSE:To control torch oscillating width and a welding speed by operating the sum of arc length and wire extension from a welding current, a wire speed and voltage between a tip and a base metal, and operating and detecting the groove width from a variation pattern of this sum. CONSTITUTION:In case of welding which uses a consumable electrode, a mean current, an effective current, a wire feed speed and voltage between a tip and a base metal are detected, the sum of arc length and wire extension, namely, a distance L between the tip and a weld metal is operated basing on a relational expression determined in advance, and a variation pattern of the distance corresponding to torch oscillating width (w) in a groove is derived. Subsequently, a minimum distance LC between the tip and the weld metal is set, torch oscillating width W which becomes LE=LC at every weld part, for instance, W1(= ¦w2-w1¦) is derived, and also the corresponding welding speed is set. In this way, it becomes possible to detect a variation of the groove width and to control automatically torch oscillating width and a welding speed.

Description

[Detailed Description of the Invention] The present invention relates to an arc welding robot that uses a consumable electrode (hereinafter referred to as a wire), and is designed to automatically change the oscillation width and welding speed according to changes in the groove width. .

If the groove width of the weld line changes, the oscillation width and welding speed can be automatically changed in response to the change in groove width. The oscillator width and welding speed can be adjusted automatically without using a special detector.

A dynamically controlled arc welding port has not yet appeared.
There is a desire for a welding robot that can simply and easily control the oscillating width and welding speed automatically.

The present invention meets such demands by detecting the welding current, wire feed trace IK, and applied pressure between the materials to be welded, which are the conditions when welding the arc welding port SR using a wire. The present invention provides a welding robot that calculates the groove width based on these values and automatically controls the oscillation width.The principle of the present invention is that when the torch is oscillated, the distance between the tip and the workpiece is wide. The gloss changes depending on the tip width, and this distance MG L is the sum of the wire protrusion lengths t and g and the arc length L = LA +
It is based on the fact that LE and LA can be found from the welding current l, the wire feed speed V, and the tip-to-weld phase voltage (2). In other words, while oscillating the torch,
, v and V to find L = LH LA 'i, then L
changes in accordance with the oscillation rate, the groove width can be detected from this change in the arm turn, and the oscillation rate width and welding speed can be adjusted in accordance with this groove width.

Hereinafter, one embodiment of the present blindness will be described with reference to the drawings. In addition,
Although the arithmetic processing according to the present invention can of course be performed by analog calculation, this embodiment shows a case where the arithmetic processing is performed by desotal calculation.

Fig. 1 shows the configuration of an arc welding robot that is an embodiment of the present invention, and Fig. 2 shows its welding condition detection system and arithmetic processing number 4 (□・rf). Torch @ 2 is a torch tilt axis (torch tilt axis), 3 is a wrist rotation axis, and by both of them, a rotation #I mechanism part for rotating the welding torch 1 is formed. 4 (・, L torch tilt axis 2 5 is a two-direction movement axis that holds the wrist rotation axis 3 and moves them in two directions (up and down directions).5 is a two-direction movement axis that holds the two-direction movement axis 4 and moves it in the Y direction (@backward direction). 6 is an X-direction movement axis that holds the Y-direction movement shaft 5 and allows it to move in the X direction (horizontal direction). 7 is the opening side 1 device. υ, remote 1・■Electric control command from the cutting board 10?) (Torch tilting via p-axis device Pe8)
21 controls the movement of the wrist rotation axis 3 and the movement axis 4.5.6, and also controls the arc welding machine 9 with control commands from the remote control panel 10 to control the welding current, welding voltage, wire feed speed, etc. Control welding conditions. Furthermore, this control device 7 includes a calculation that automatically changes 1fRX in response to a change in the groove width of the welding line, a control function and a calculated opening. There is also a built-in computer rIH that automatically changes the welding speed J-■ according to the tip width. In Figure 2, reference numeral 11 denotes a consumable electrode (wire), which is wound around a wire reel 19 and driven by a feed motor 21 (rollers 20, 20').
It is fed by the tip 15. 12 is a welding metal arc, 13 is a bath arc, and 14 is a weld metal LA. A shield gas nozzle 16 supplies a shield gas 17 to protect the arc 13 and the weld metal 14 from the entire atmosphere. , , 18 is a terminal for connecting a power cable from the power source of the arc welding machine 9, and is electrically connected to the chip 15. 22 is the mountain for detecting the welding '1 flow: v'lU J, 4! Izumi y,”f
23 is a pressure detector, such as a potentiometer, 24 is a shunt for detecting the voltage between the chip 15 and the wave absorbing device 12; A 7'ζ tachometer detector for detecting dust, such as a rotary encoder. 25 is an amplifier that converts the signal from the rotary encoder 24 into a DC voltage and amplifies it to an appropriate magnitude, and 26 is a potentiometer 23. 27 is a shunt 22 that amplifies the signal to an appropriate size.
28 is an amplifier that converts the signal from the shunt 22 into a signal corresponding to the effective current and amplifies it to an appropriate size. 29, 30, 31.32 are amplifiers 25°26
．． This is an A/D converter for converting 27.28 analog signals into digital signals and inputting the digital signals to the control device 7.

In FIG. 2, the same numbers as in FIG. 1 indicate the same members.

In this device configured in this way, the torch tilt axis 21 wrist rotation axis 3 and movement axis 4 are controlled by commands from the remote control panel 10.
, 5 and 6, the welding torch 1 can assume any three-dimensional welding posture within these movable ranges.

Also, by command from the remote control panel 10, the welding teaching position is'
The torch posture and welding conditions can be stored in advance in the control device 7 every 5 times.

Next, we will explain how to calculate the sum of the arc length (5 people) and the wire protrusion length (LH). Current worker: Average current of welding current I (AITIp) IE: Effective current of I (Amp) for welding electric current γ1 V: Volt at 't between tip 15 and welded part 12 V: Wire feed Feeding speed (key/5ee) LE: Wire 1 from the tip of tip 15 to arc 131
1 long protruding length) (mm) LA: Distance from the tip of wire [1 to weld metal 1414- (arc length) (- L: L=LE+LA, that is, distance 1 between tip 15 and weld metal 14 (Simplified) vB: Voltage drop (Volt) generated on the wire protrusion due to welding DC ■ VA: V person = V-Vo, i.e. arc voltage (Volt)
Then, the relationship between the above various percentages is approximately as follows.

LD = ft (IA, Ig, v)
・・・・・・Formula (1+VB ” fz (I
A, v, LB) -,,
, -8 formula (2) vA = v-vE
・-・”Formula (3) LA = fs (IA,
VA) ・”Set (4) L=LH+L
People...Formula (5)
The relationship in equation (1) above can be found as shown in "Study on Current Controlled Arc Welding", July 1980, 6 lines, by the Welding Method Committee of the Welding Society of Japan::+'+5 pages (from formula 121) In addition, the relationship of the above equation (4) can be found on page 43105 (3,1,10
), where d is determined as the diameter of the wire. On the other hand, the specific relationship of the above equation (2) can be found through experiments. Incidentally, the relationship between the above equation (3) and equation (5) is obvious from FIG.

The control device 7 is programmed with the relationships expressed by equations (1) to (5) above. Accordingly, the controller 7 performs the following calculations.

(a) When the average current of one welding electrician and the effective current IB and wire feed speed [v are given to the shunt 22 and rotary encoder 24 through the % converter 31 and 32° 29 to the control device 7, The protruding length of the wire 11 is determined by calculating the formula il+.

(b) When the worker, (ii) and LB obtained in (a) above are given, the voltage drop vF at the shear wire protrusion is calculated by calculating equation (2).

(/) When the applied voltage V is applied via the potentiometer 23 and the % converter 30, this voltage V and the above (b)
From the pressure drop vB obtained in step 7, the arc voltage VA can be found by calculating equation (3).

) average current IA and the above (/now obtained arc voltage V
From A, the arc length LA is determined by calculating equation (4).

(g) From the wire protrusion length LE obtained in above (a) and the arc length LA obtained in It will be done.

Now, consider a material to be welded 12 whose groove width changes as shown in Fig. 143. 4 is a sectional view taken along the line IV--IV in FIG. 3, and FIG. 5 is a sectional view taken along the line 2--2 in FIG. The groove width of the welding part in Fig. 4 is also larger than the groove width of the welding part in Fig. 5, and L = LA + LB for the oscillation width W when oscillating within the groove in Fig. 4. The change pattern is somewhat sharp as shown in Fig. 6, and L = LA for the oscillation rate width W when oscillating within the groove shown in Fig. 5.
The 4th turn of +L and E changes becomes broad as shown in Figure 7. However, the case is shown in which the center side of the groove and the center line of the ossileate coincide.

In any case of 9 turns of change, when the minimum distance F+fI La between the step 15 and the weld metal 14 is set,
The otsolate width is WI (=IW2-WI I ).

It is determined as Wl (=IW4wsl). Therefore, the control device 7 performs the following control following the calculations (a) to (i) above.

(F) Set the LO value on the remote control panel 10.

(g) From the change in L obtained in (e) above, for each melt 1 concubine 79i, the oscillation rate + distance W (W in m6 diagram, 'V in % diagram 7) that makes L = Lo. ).

(B) Change the W care analog amount obtained in (G) above; so that the oscillation width becomes W or a width proportional to these. Input to the 4L dynamic drive device 8, 5.
Control 6.

In this way, when Lo is set, the oscillating width W is automatically determined according to the size of the groove 11/bl, and welding can be performed according to the groove width. For example, in the groove shown in Fig. 4 (Fig. 6), L = LO.
Reverse it and move it to the right so that L=Lo w=
If the oscillation is performed by further inverting l·-chi 1 and moving it to the left at w2, the oscillation can be performed at the sumo 1 corresponding to the groove width here.

Furthermore, for example, in the groove shown in FIG. 5 (FIG. 7),
L = Lo becomes W ''' At W3, reverse the torch 1 and move it to the right, and L = Lo becomes w =
At W4, if the torch 1 is further reversed and moved to the left to perform oscillation, oscillation can be performed with a width corresponding to the groove width.

On the other hand, if the l'fJ Ke speed is kept constant even though the oscillation width varies according to the weld groove width, the bead depth H will be found to be non-uniform. That is, the bead groove 11 in FIG. 4 has a small groove width. and the bead height H in Fig. 5 where the groove width is large.
2, at the same welding speed, HI>H2. Therefore, if one welding speed is controlled according to the groove width, the same girdle height can always be obtained. bite, i:
Figure 1JJ6: Oscillator 11 in Figures 13 and 7
琵W+ = l Wl WI I and Wl = l
Find W4-vr31, and calculate this W8 and Wl
The control device 7 may be programmed in advance so that a welding speed that is approximately inversely proportional to is automatically set.

As a result, the welding speed changes according to the oscillation width, and the bead height remains constant.

As described above, the minimum distance LO between the tip 15 and the weld metal 14 is set, and L=L from the pattern of L and W obtained by oscillation.

By determining the oxidation rate) At at this point, reversing the oxidation direction at this point, and controlling the welding speed according to the oxidation rate width, it is possible to obtain a defect-free welded joint even if the groove width changes. .

As specifically explained in conjunction with the examples below, according to the present invention, the groove width can be detected from only the welding conditions without using a special detector, and even if the groove width changes, the groove width can be detected automatically. The oscillating width and welding speed are varied to obtain defect-free welded joints. Therefore, highly accurate unmanned welding is possible.

[Brief explanation of the drawing]

The drawings relate to an embodiment of the present invention; FIG. 1 is a side view showing the configuration of a non-embodiment, FIG. 2 is a block diagram showing the welding condition detection system and calculation machine, and FIG. is a perspective view showing the material to be welded where the groove width changes, and Figure 4 is ■-v in Figure 3.
H cross-sectional view, Figure 185 is a cross-sectional view taken along line V-Y in Figure 3, No. 6
The figure is a graph of the change pattern of the distance between the tip and the welding sound +1 with respect to the oscillation width within the groove of Figure 4, and Figure 7 is a graph similar to Figure 6 within the groove of Figure 5. . In the drawing, 1 is a welding torch, 2 is a torch tilt axis, 3 is a wrist rotation axis, 4 is a two-direction movement axis, and 5 is a Y-direction movement axis. 6 is an X-direction moving axis, 7 is a control device, and 8 is an electric drive unit Fj. 9 is arc welding, 1 run, 11 is consumable 1 toy f (wire), l2 is welded +4. 15 is a chip, 22 is a shunt, 23 is a potentiometer, and 24 is a rotary encoder. Patent Applicant Mitsubishi Electric Kuri Co., Ltd. Sub-Attorney (!ii) Former Ishi Shibu (and 1 other person) No. 6 II Figure 7 W3 -W2- W4

Claims (1)

[Claims] The welding torch can be moved to any point in three-dimensional space and can take any desired torch posture, and the welding torch can be oscillated using a consumable electrode or wire. Welding current (IA: average current, IB: effective current) in an arc welding robot that performs arc welding while A detector for detecting the wire feeding speed (V) and the F voltage (V) between the tip and the welded material, and the above-mentioned welding current (λ, IE) based on a predetermined relational expression. By processing each value of the wire feeding speed (v) and voltage M, the difference (LA + LB) between the arc length (LA) and the wire protrusion length (Lg) is determined, and the above is calculated by the welding torch oscillation rate. length, 1 bite (
The oscillation width and welding are determined according to the change in the groove width of the welding line by a calculation detection means that detects the groove width from the change pattern of LA + LE) and by moving the welding torch based on the detected groove width. An arc welding robot characterized by being equipped with a drive device that automatically changes speed.