JPS5966974A - Welding robot - Google Patents

Abstract

PURPOSE:To form a weld zone having high quality by welding with a robot for consumable electrode type arc welding which is capable of welding with weaving by setting the positional information at the point where the weaving passes in said robot and performing welding with weaving by said robot. CONSTITUTION:Fillet welding of base materials with a consumable electrode type arc welding torch which is weaved by a welding robot is accomplished by providing a means for teaching the positional information on each one point of one right and left cycle including the beginning point for weaving and the end point of the weaving and repeating the above-mentioned one cycle, and setting the positional information at the point where the weaving passes in the robot. The information on the position where the condition for performing welding in the midway is detected is also set in the above-mentioned set information to take the condition for performing welding in one end position of the weaving and the position where the condition for performing the welding is detected into the robot. The position of the welding torch is corrected by such condition, whereby the fillet weld zone having good quality is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a welding robot, and particularly to one that enables weaving welding with good results.

Various welding robots that automate weaving welding are known (for example, Japanese Patent Laid-Open No. 14139/1983). Furthermore, when performing weaving welding while following the welding line using a consumable electrode type arc welding torch, any of the welding conditions such as arc current at both left and right ends during weaving, consumable electrode protrusion length, arc length, and arc voltage. It is well known, for example, in Japanese Unexamined Patent Publication No. 51-91851, to perform copying so that the values are approximately equal.

However, in conventional weaving pattern welding, good results can be obtained when the shape of the weld line groove is symmetrical in the left-right (weaving swing) direction with respect to the direction of gravity. .

In the case of other grooves, such as horizontal fillet weld lines or rectangular groove lines, good results may not always be obtained; for example, in the case of horizontal fillet weld lines, the first An undercut portion AN as shown in the figure is generated.

Therefore, in this invention, when teaching the necessary points including the left and right ends of the weaving trajectory, we also teach a point for comparing arc current, etc., so that the current, etc. between this point and the end point can be compared. The main objective is to provide a welding robot that can solve the above-mentioned problems.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is an overall view including a rectangular coordinate welding robot RO, which is the background of this invention and is effective by implementing the invention in parentheses, but this invention is not limited to this embodiment.

1 is a well-known rectangular coordinate (x + y + z
) is the vertical axis configured at the terminal of the robot RO.

Reference numeral 2 denotes a first arm supported at the lower end of the vertical shaft 1 so as to be able to rotate α by one dimension of the shaft.

A second arm 3 is supported at the tip of the arm 2 by an oblique shaft 3a so as to be able to rotate β. A coffin holder 3b is provided at the tip of the second arm 3 for holding a processing tool (in this embodiment, a consumable electrode type MIG welding torch T) as an end effector.

The shaft 1, the shaft 3a, and the central axis TC of the torch T are configured to intersect at one point P (the operating point of the torch T). Furthermore, the torch T is arranged such that its welding operating point coincides with the point P and hangs.

Thus, by controlling the angles α and β, the attitude angle θ and the turning angle ψ of the torch T with respect to the vertical axis 1 can be controlled.

4 is a known welding power supply device. The device 4 is equipped with a spool 4a wound with a consumable electrode TW of a torch T.
It is configured such that a welding power source 4b can be connected between W and the workpiece WK.

Reference numeral 5 denotes a known computer as a control means for the entire embodiment. The combination unit 5 includes a CPU and memory.

Connected to the path line B of the computer 5 is a circuit that controls the power supply 4b and controls its operating state as a feeder.

The path line B is further connected to the y-axis Za=Bo system Sx of the robot RO. The servo system Sx has y-axis power Mx
, and an encoder Ex that outputs the position information.

Similarly, a similarly configured y-axis servo system S'l, z-axis servo system Sz, α-axis servo system Sα, and β-axis servo system Sβ are connected to the pass line B.

RE is a remote control panel and is provided with a group of manually operated snap switches SW. And x, y, z.

If the snap switch for each θ and ψ control axis is pushed to the "U" side, the position and angle information for that control axis will increase, and if it is pushed to the rDJ side, the end effector will move in the opposite direction. be done. In this case, α
, angle information of β and θ.

The angle information of ψ is converted through a conversion means.

Since this conversion means is well known, it will not be described in detail here.

The operation panel RE is equipped with a speed command rotary switch Sv. In addition, a mode changeover switch SM is provided, including manual mode M, test mode TE and auto mode AU.
It is configured so that it can be switched to SE is a designation switch, and by switching it upward in the figure and operating the up/down switch SU, the repetition pattern number (RNα) is displayed and set. Furthermore, by moving this switch SE to the left as shown in the figure and operating switch SU, linear interpolation r
LJ, circular interpolation "C", and repetition 1-R" are displayed and set in this order. Further, when the switch SF is switched to the right in the figure and the switch SU is operated, a welding condition number (WNα) is displayed and set. Furthermore, the operation panel RE is provided with a pair of welding current detection command switches SI and a start switch ST, A and B. In particular, the function of switch ST will be explained in detail in the explanation of its operation below. These switches are then connected to cross line B.

In addition, when the switch S■ is in the manual mode, by pressing its head, you can switch the
The speed of movement is stored as a constant value.

The effects of the above-mentioned embodiments will be described below. Please also refer to Figure 3 et seq.

The workpiece WK now has horizontal corner self-welding lines WL and WB2 as shown in the figure, and these welding lines WL and WB2
shall be attempted for horizontal fillet weaving welding.

1. The operator activates the entire device by energizing it, operates the switch SM, and sets it to manual mode M.
Operate switch S■ to set the movement speed Vo in manual mode. It is assumed that the point P of the torch T is now at the position PO shown in FIG. 2, and the teaching operation is performed through the following steps.

(T1) First, operate the switch SW to move the torch T above the illustrated Lwl (the welding starting point on the welding line WI, I), and at the same time adjust the angle of the torch T to the appropriate position for welding. (dashed line). Next, switch SE is switched to the left as shown, and switch SU is operated to select and set "L". Also, switch SE is turned upward in the figure, and switch SU is operated to display and set the repetition pattern number R+ (for example, 01). Furthermore, operate the switch SV to turn the torch T in auto mode.
Set the command speed Vl to move the motor to LWl. Then press switch ST.

In response to the operation of the switch ST, the computer 5
Each axis (X+
y + 'Z + θ, ψ) information, set "L"
The command, repetition pattern number "Ol", and command speed vI are taken into memory. The computer 5 thus takes in this information as command information for the first step of the user program.

(After T, operate the switch SW to move the torch T to the
PI (the first target point for weaving on the welding line WLI) and at the same time control the angle of the torch T to an appropriate posture for welding. Next, switch SE is switched to the left as shown, and switch SU is operated to select [R-1]. Then, operate the switch S■ to set the command welding speed - to move the torch T from Lwl to WP+ in auto mode. Furthermore, switch SE is switched to the right in the figure, and switch SU is operated to set welding condition (voltage, current) number W (for example, [1oJ).

Then, operate the rAJ switch of the switch SI, and then press the switch ST.

In response to the operation of the switch ST, the computer 5 takes into the memory information on each axis corresponding to the position and orientation of the 1--chi T controlled as described above. Also, the set "R" command, welding condition number "lO", welding speed vw and current detection command rA
J, import the repetition pattern number "01" set in (T]) into the memory.

(T3) Next, operate the switch SW to move the torch T onto the illustrated WP2 (the second target point of weaving on the welding line WLI), and at the same time control the angle of the torch T to an appropriate posture for welding. . Furthermore, operate the switch S■ to clear the previous rAJ, and then press the switch ST.

Similarly, the combination 5 takes in the information of each axis corresponding to the controlled position and orientation of the torch T into the memory. It's Kade.
R” command, pattern number roll, welding condition number “10”
", and welding speed ■7 are imported into memory.

('rA) Next, operate the switch SW to move the torch T onto the illustrated W P3 (welding line WL, the third target point of upper weaving), and at the same time adjust the angle of the torch T to an appropriate posture for welding. to control. Then, operate the switch S■ to set the command rBJ, and then press the switch ST.

Similarly, the computer 5 stores information on each axis corresponding to the controlled position and orientation of 1.-chi.T into the memory. Also,
rRj command, putter 7 number roll, welding condition number rl
0 (']?,) Next, operate the switch SW to move the torch T to the diagram W P4 (the fourth target point of weaving on the welding line WLI). ) and at the same time control the angle of the torch T to an appropriate posture for welding. After clearing the command rBJ, the switch ST is pressed.

Similarly, the computer 5 captures information on each axis corresponding to the controlled position and orientation of the torch T into the memory. Also,"
R” command, pattern number “01”, welding condition number “10”
", and the welding speed■ are imported into memory.

('Ih) Operate the switch SW to indicate ■-chi T.
The torch T is moved onto W2 (the welding end point on the welding line WLl), and the angle of the torch T is controlled at the same time. Also, select "L" by operating SWIN, CH SE, and SU in the same manner as described above. Then press switch ST.

Similarly, the computer 5 stores information on each axis corresponding to the controlled position and orientation of the torch T in memory as rLJ command, pattern number roll, welding condition number "lO", welding speed, and next step information. Incorporate into.

(Th) Next, operate the switch SW to retract the torch T to the PO position shown in the figure. Additionally switches SE and S
Operate U to clear repeat pattern number "01" and welding condition number "10".

Then, the speed Vl is set by operating the switch Sv.

Then press switch ST. The computer 5 similarly stores information on each axis corresponding to the position and orientation of the torch T, as well as the ILj command and the command speed 1, into the memory as information for the next step. Until now, information on LandOIJ or IRandOIJ has been included, and since neither of these has been included this time, it is determined that the series of teachings up until now includes a new turn.

Then, from this series of information, a series of weaving pattern information is recalculated as a position in the local coordinate system, and this, including the WN[Ll command speed and detection command, is separately stored together with rRjNα (rolJ).

This calculation will be explained below. See also FIG.

That is, as shown in FIG. 5, the welding line WL of the workpiece WK
(absolute coordinate system of robot R with respect to
P21W P3 + W P71. When the position of each point on LW2 is taught, the coordinates are converted to a position in the local coordinate system ξηζ fixed to this work WK.

That is, the origin O of the xyz system is translated to point LWI,
Rotate Φ around two axes, then -(-
By performing L-〇) rotation, change the new y-axis to LWI.
Match LW2.

If this axis is the ξ-axis, the y-axis is the η-axis, and the two axes are the ξ-axis.

Let M be the position transformation matrix from (xyz) to (ξηζ), and each of the above-mentioned points expressed in the (ξηζ) system has the following equation with respect to the position: ) for the pose rw = xw −x.

Here, w = 0 to z (t is the number of points that make a turn and is 4 in this example, and is stored in the male IJ as t = 4), and XO is 0, which is the position of Lw4. And this J
Remember this as a generalized noz-turn with llrw as a repeat.

At the same time as
Find the relationship between wl and Lw2. Torch T in Lwl
Since the attitude of is expressed by the Euler angle (θψ),
The direction cosine of the direction vector 1 of the torch T is as follows: TX-sinθIcO5ψ1 7'y-sinθ1sinψ1 ゛TZ-轻θ′ Here, θ and ψ are the Euler angles of the torch T at the point LW1.

Therefore, the vector product 7 X LWI LW2 becomes as shown in FIG. In the case of welding, since the welding result will be good if the torch T is directed downward, this has an important meaning. 7 X Lwl Lw2 = axi4-ayj+az
Remember the coefficient a of J.

To explain this coefficient a2 in more detail, if the direction cosine of the torch T is αT (αT, βT, γT), and LwILw2 is (〃)z−P+)−(Δwork, Δy, ΔL), then =
Standing (ΔγT−ΔβT) 10i (Δ2αT−ΔeγT
)-+4(ΔYβT−Δ,γT), that is, (ΔEβT−ΔAγT) is the coefficient of A.

At the same time, the pitch Lwl wm of the repeating pattern is memorized. In this case, wB is the position of the final point (WP4 in this embodiment) taught as a repeating pattern.

(T8) Next, the operator controls the position and attitude of the torch to the position of the starting point Lw++ of the welding line WL where the same repeating pattern is desired to be executed. Furthermore, a similar repeat pattern number "01" is set. Then switch ST
Press. The combination coater 5 includes information on each axis corresponding to the position and orientation of the torch T controlled in the same manner, r L J commands,
The number "01" and the command speed vl are taken into the memory as information for the next step.

1) The operator controls the position and attitude of the torch to the position of the end point LW12 of the welding line WL2. Further, a welding condition number "lO" and speed °- corresponding to a similar repeating pattern are set. Then press switch ST.

Similarly, the computer 5 receives information on each axis corresponding to the position and orientation of the controlled torch T, the "L" command, and the number "Ol".
” and “10”, and the command speed ■ are taken into the memory as information for the next step. 0 (T+o) Next, operate the switch SW to retract the torch T to the position PO shown in the figure. Further, by operating switches SE and SU, repeat pattern number [0]'' and welding condition number ``10'' are cleared.

and operate Swing-8U to set speed ■1.

After that, the computer 5 which presses the switch ST takes in the information of each axis corresponding to the position and orientation of the torch T controlled in the same manner, the rLJ command and the command speed Vl into the memory as information for the next step.

In this way, the teaching of a series of user programs is completed, and the command information at each teaching point in this embodiment is summarized in a table as shown in the following table.

Also, in this table, as mentioned above, each piece of information included in the command "R" is stored in the pattern storage section in the memory, and other information is stored in the user program step storage section. I want to be understood. Also, the number of times the command "R" is issued, in this case "4", is stored in the memory as the value of rt, I+.

Next, switch SM is operated to set the test mode, a known test is executed, and if there is a mistake in the program, it is corrected.

Then, by operating the switch SM to set the auto mode and operating the switch ST, repeat pattern copy welding is automatically executed by the following steps.

(A+)'! First, the computer 5 loads the step information of the program to be executed next using the system program stored in the step storage section in its memory (process PR1).

(A2) Determine whether the contents of this information include the command rLJ and <roll pattern number (in this case, roll) (processing PR; z).

(Person 3) If it is included, the next step information is further loaded (processing PR3).

(A, I) Then, it is determined whether the contents include the command rLJ and the repetition pattern number "Ol" (
Processing PR4).

(A5) If included, calculate the number of repetitions n (processing PR5) O, that is, n = C (LWI LW2 / LwlWP4' +
0.5) ':] However, 0 is a Gaussian symbol.

(AI,) If the process PR2 and PR4 are not completed, the repetition ends in both cases.

Then, following process PR5, the position information of the linear interpolation internal portion) fm (Xm + 3'rn + Z m + θm, ψ
As m), first, information on the weaving start point Lwl is loaded (processing PR(1)).

(A7) Then, set the values of W and m in memory to 10.
(processing PR7).

(A8) And the increment Xw (X'w, y'
w, z′w.

θW, ψW) are calculated (processing PR). At this time,
The sign of the η-axis is determined so that the sign of the coefficient of f of 7 X LvILw2 during teaching and 7 X LWI LW2 when reproducing in auto mode matches.

Letting the inverse transformation matrix at that time be I, the increment X'W is x'w-M-' ・Xw (ξ, 77,
() Regarding the posture, x'w == Xw (θ, ψ).

(A9) If χ short is calculated, this increment is taken into account,
xw−xm+xw is calculated (processing PR9).

That is, >tw=xm-t-xw (where w=0~t) is (x
'yz) The new command value to be given in the system is 0 (AIO) Furthermore, it is determined whether there is a welding current detection command A or B corresponding to this point xw (processing PRIO).

In this case, the teaching point corresponding to point IW is WP.

Please remember that it is "A" for WP3 and rBJ for WP3.

(An) Then, the detection outputs of A and B are compared (processing PRn).

(A12) If A-B'k o, correct the position information of xw in the direction of A-B=O (process p-R12
).

This position information can be corrected by knowing the direction of the axis TC from the Euler angle (θ and ψ) of the torch T, and then knowing the direction of the axis TC and the direction of the welding lines WL and l (the direction of the straight line connecting points Lwl and Lw2). ), and in the direction with the smaller welding current value between A and B, a predetermined constant dimension △
Only T is corrected. Apart from this, IA-
It is also possible to predetermine and store a larger correction amount as Bl becomes larger, and call this value to make corrections.

(Al: () Then, this corrected mW position information is output as a position command (processing PR13).

(AI4) If command A or B is not included in process PR1, or if A-B=0 in process PRY, the value of XW is output as is as the position command value (process PR14).
).

(Al5) Next, set w = V/ + 1 (processing PR
ts).

(AI6) Then, determine whether it is w-t (processing P
R16).

(A17) If so, it means that 1 cycles of repetition have been completed, and m = m + 1 (Processing PR] 7)
.

If not in processing PR R+6, return to processing PRs,
Return 9 until w = 1.

(Al8) Following processing PR+7, a linear interpolation point xm is calculated (processing PR+s). The method of determining the position information of the linear interpolation point is well known as disclosed in the aforementioned Japanese Patent Laid-Open Publication No. 53-14139, and therefore will not be described in detail.

(A, 19) Next, determine whether m=n (processing PR19
).

(A20) If so, it means that all interpolation has been completed, and XW = Xm is set (processing PR2D).

(A21) After that, XW is output as a command value (process PR21), and the process returns to process PR3.

(If not in Aθ processing PR+9, set w=(l) (processing PR22) and return to processing PR8.

In this way, it is only possible to repeat weaving welding from point Lwl to Lwz on the welding line WLI under the taught welding condition WN [L1'0 and at the command speed W, while following the welding line WL. Instead, weaving tracing welding can be performed in the same pattern from point Lwo to Lw12 on the other weld 1WLz.

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

(1) In addition to the mechanical configuration of the robot RO, which has a rectangular coordinate system, even if it has a polar coordinate system, one cylindrical coordinate system, or a multi-joint system, the robot RO can convert the position information into a rectangular coordinate control system ( For example, the method disclosed in Japanese Unexamined Patent Publication No. 57-27689) can be implemented.

(11) In addition to the horizontal corner self-welding line, it is effective to form the groove on a weld line that is asymmetrical with respect to the direction of gravity, such as a rectangular groove weld line.

G11) In the above embodiment, the welding line was followed so that the detected values at A and B of the welding execution condition detection points WPI and WF2 were equal. However, to be precise, this is just a one-dimensional model.

If the reference value at A and B is taught at the time of teaching, and the detected values at A and B are made equal to this reference value, two-dimensional imitation will be achieved.

(Incorporated Foundation) The detected value of welding execution conditions may be other conditions such as welding voltage instead of welding current.

(2) In the above embodiment, weaving was repeated in a straight line. By setting this to "C"
It is also possible to repeat the weaving twice in the same way.Instead of teaching each point information of the weaving for only one cycle and repeating it, it is possible to teach all the points of the weaving. be.

(b) Furthermore, instead of the operator inputting the welding conditions detection point each time during teaching, the point (w p3 ) located several millimeters inside from one end of the weaving can be determined by, for example, the welding current value, weaving width, etc. The computer stores in advance a table that indicates which detection points should be used, and the computer does not teach the detection points during teaching, but automatically determines the detection points in the auto mode, as in the embodiment described above. It is also possible to follow the welding line.

■ Other replacements of each component with equivalents within the scope of the technical idea of this invention are also included within the technical scope of this invention.

Since this invention is as described above, it has a simple configuration,
In a welding robot that is designed to follow while weaving a groove that is asymmetrical with respect to the direction of gravity, the point at which welding conditions are taken in to follow the weld line is not at both the left and right ends, but at one end in the middle of the weaving path. The weaving welding method for asymmetrical grooves such as the one shown in FIG.

[Brief explanation of drawings]

Fig. 1 is a side view showing welding results by a conventional welding robot, Fig. 2 and subsequent figures show an embodiment of the present invention, Fig. 2 is an overall view with a part perspectively shown, and Figs. 3 and 5 show the operation. FIG. 4 is an explanatory perspective view, FIG. 4 is a side view for explaining the operation, and FIG. 6 is a flow chart. T・Consumable electrode type welding torch, RO welding torch, WK
-'None, WL, and WL2 horizontal corner self-welding lines;
RE/remote control panel, 5 computer, SI welding current detection command switch. 39 D-゛ continuation supplement iT-shi (
Sa1 artificial)1! JCF TO's ♂〈Nj く昭■t15'74F う"tt'j Ｇａｎｄ qgsy
9 No. 2, Relation to Tenancy of the Invention (2) of the Invention Applicant Address: 1-5-25-Gin-5, Kozone-cho, Nishinomiya City, Hyogo Prefecture, Number of Inventions Increased by Amendment r) L399-

Claims (2)

[Claims] (1) A welding robot equipped with a consumable electrode type arc welding torch as an end effector and capable of weaving welding includes means for setting information on the position of each passing point of the weaving, and this means includes information on the positions of each passing point of the weaving. In addition to point position information, midway welding execution condition detection point position information is set, and means for importing welding execution conditions at one end position of weaving and the welding execution condition detection point position, The welding robot described above, comprising means for correcting the torch position. (2) The weaving passing point position information setting means is provided with means for teaching each point position information of one cycle including the weaving start point and the weaving end point, and further repeating the l cycle. A welding robot according to claim 1.