JPS5856105A - Industrial robot - Google Patents

Abstract

PURPOSE:To allow a playback robot to repeat work on an arc work line by storing a pattern to be repeated on an arc as local coordinate information and teaching the robot. CONSTITUTION:A power source 4b is connected to the bus line B of a computer 5. The bus line B connects with the x-axis servo system Sx, y-axis servo system Sy, two-axis servo system Sz, alpha-axis servo system Salpha, and beta-axis servo system Sbeta of a robot RO. A work WK has nearly horizontal fillet arc welding lines WL1 and WL2, and fillet weaving welding is carried out along said welding lines WL1 and WL2. When respective point positions of repetitive weaving patterns Cw1, w1, w2, Cw2, and Cw3 are taught by the absolute coordinate system (xyz) of the robot RO with regard to the welding line WL1 of the work WK, coordinate conversion to the fixed local coordinate system xsietazeta of this work WK is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of an industrial blur robot, and in particular to a robot that facilitates teaching when repeating the same pattern on a circular arc. For example, welding is widely performed as weaving welding or tuck welding, and playback robots usually require teaching all information about each point of the process. In order to eliminate the complexity of the flattening 8, when the processing line is a straight line, prior art applications have been filed by the same applicant as the applicant of this invention, and Japanese Patent Publication No. 52-13782 and Japanese Patent Publication No. 52-13782, respectively.
Japanese Patent Publication No. 58-4828 and Japanese Patent Publication No. 58-141
It is disclosed in Publication No. 89. However, in these conventional techniques, if the position information of each point in one cycle is taught between the start and end points of a certain machining line, this can only be automatically executed up to the end point, and the same pattern on other machining lines can only be taught. If you try to repeat , you will need to perform the same teaching at that location again, and it cannot be used if the machining line is an arc. -0 Therefore, the inventor of this invention created a repeating pattern on an arc by -
The present invention was completed based on the idea that the above-mentioned complications could be further eliminated if the H teaching could be repeated on other circular arc machining lines.

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

FIG. 1 is an overall view including a rectangular coordinate welding robot (RO) that is effective by implementing the parenthesized invention, which is the background of this invention, but the invention is not limited to this embodiment.

1 is a known orthogonal coordinate ('X*Ve2) whose details are not shown.
A 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 axis l so as to be able to pivot α about the axis i1.

A second arm 8 is supported at the tip of the arm 2 by an oblique shaft 8a so as to be able to rotate β. At the tip of the second arm 8゜ is a processing tool as an end effector (in this example, a MIG welding torch T).
) is provided with a gripping tool 8b for gripping.

The axis 8a of the shaft 11 and the central axis TC of the torch T are configured to intersect at one point P.

Furthermore, the torch T is configured such that its welding operating point can coincide with the point P. 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 l can be controlled.

4 is a known welding power supply device. The device 4 is equipped with a spool 4 & winding up the consumable electrode TV of the 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 computer 5 includes a CPU and a memory. A power supply 4b is connected to a path line B of the computer 5.

The pass line B is further connected to an X-axis servo system Sx of the robot R. The servo system Sx has X-axis power M x
, and an encoder Ex that outputs the position information. Similarly, the /x line B is connected to an iy-axis servo system Sys, a z-axis servo system Sz, a sa-axis servo system Sα, and a β-axis servo system Sβ.

RE is a remote control panel and is provided with a group of manually operated snap switches SW. Then, turn the snap switch for each of the x, y, and 2 control axes to the rUJ side.If you turn it down, the position information for that control axis will increase (direction away from point M), and if you turn it to the "D" side, it will do the opposite. Snap switches corresponding to each control angle of 0, θ, and ψ configured to move the end effector in the direction are also "U"
When the torch T is tilted to the side, the torch T is rotated in a direction away from the origin, and when tilted to the "D" side, the torch T is rotated in the opposite direction.

The operation panel RE is also provided with a speed command rotary switch Sv and a mode changeover switch SM, so that it can be switched to manual mode M1 test mode TE and auto mode MAN. SE is a designated switch, and by switching it upward in the figure and operating the up/down switch SU, the repeating pattern number (RNa,) is displayed and selected.
Further, by setting the switch SE to the left as shown in the figure and operating the switch SU, linear interpolation rLJ, circular interpolation "C", and repetition rRJ are selected and displayed in this order. Furthermore, when the switch SE is switched to the right in the figure and the confectionery shop 7 switch is operated, the welding condition number (Wm) is displayed and is to be selected. Furthermore, the operation panel RE is provided with a start switch ST. switch S
The function of T will be explained in detail in the explanation of the function described later. These switches are then connected to path line B.

Note that the switch Sv is configured so that by pressing its head in the manual mode, the moving speed of the torch T in the manual mode is stored as a constant value.

The effects of the above-mentioned embodiments will be described below. Please also refer to Figure 2 et seq.

Now, the workpiece WK has #1 horizontal corner arc welding lines WL and WL2 as shown in the figure, and these welding lines WL,
It is assumed that fillet weaving welding is to be performed on both WL2 and WL2.

The operator first performs teaching as follows.

(1) Operate the switch SM to set the manual mode as shown in the figure, and select the switch Sv to a speed Vm suitable for moving the torch T by manual operation (step Sl).

At this time, the torch T is assumed to be in the standby position shown in the figure.

Manually move the torch T so that the rotation and attitude angles (θ and ψ) of the torch T are at angles suitable for welding (step S2■).
.

(8) Next, with the switch SE turned to the left as shown in the figure, operate the switch SU to select and set "C" (Step S2■)0 Also, turn the switch SE upward in the figure, and switch By operating SU, the repetition pattern number Rr (for example, 01) is displayed and selected (step S2).

Furthermore, by operating the switch Sv, the command speed V to move the torch T from the standby position to Cwl in the auto mode is set.
o is set (step S2).

(4) After that, press switch ST (step 53).
)0 (5) In response to the operation of the switch ST in step S8, the computer 5 sets each axis (X + 3
', Z + θ, ψ) into the memory 0 Also, at this time, "C" set in step S2
Command, repetition pattern number “Ol” and command speed v
0 into the memory (step 54) (6) Next, operate the switch SW to move the torch T to the W shown in the figure.
l (second target point of weaving on weld line WLI)
The torch T is moved upward, and the angle of the torch T is similarly controlled to a posture suitable for welding (step S5).

(7) Next, switch SE is switched to the left as shown, and switch SU is operated to select the repeat command "R" (step S5).

Furthermore, by operating the switch Sv, when the torch T is moved from the point LWl in the auto mode, the commanded welding speed Vl is set (step S5). Operate switch SU to set welding conditions (e.g. voltage, current)
Set the number Wi (e.g. “lO”) (step 55
0).

(8) Then press switch ST (step S
6).

(9) In response to the operation of the switch ST in step S6, the computer 5 is controlled in step S5 and similarly captures information on each axis corresponding to the position and orientation of the next torch T into the memory.

In addition, the "R" command, welding condition number "lO" and welding speed ■1 set in step S5, and the repetition pattern number "Ol" set in step 'S2 are also taken into memory (step 87). .

(The next step is to operate the switch SW to move the torch T to W2.)
(the 8th target point of weaving above the welding line WL) and at the same time control the angle of the torch T to a position suitable for welding All welding (step S8).

(11) Then press switch ST (step S9
).

((2) Similarly, the computer 5 stores information on each axis corresponding to the position and orientation of the torch T controlled in step S8 in the memory. Also, the computer 5 stores the rRJ command, the pattern number "Ol", and the welding condition number "10'', and welding speed vl
is captured into memory (step 810).

(1:3) Operate switch SW to move torch T to C
It is moved onto W2 (welding line WL, upper welding midpoint) and at the same time the angle of the torch T is controlled (step 811).

(M) Also, operate switches SE and SU in the same manner as described above to select "C" (step 811■) 0 (15)
Thereafter, the switch ST is pressed (step 512) 0 (16) Similarly, the computer 5 takes into memory the output information of each axis corresponding to the position and orientation of the torch T controlled in step Sll. Further, the "IC" command, the pattern number "Ol", the welding condition number "10", and the welding speed vl are taken into the memory (step 818).

(r?) Operate the switch SW to turn the torch T CW as shown.
3 (the welding end point on the welding line WLI) and at the same time control the angle of the torch T (step 514) 0 (18) Then, press the switch ST (step 51
5).

(■Similarly, the combiator 5 takes in the information of each axis corresponding to the position and orientation of the torch T controlled in step 814 into the memory. Also, the "C" command, the pattern number "
01'', welding condition number ``lO'', and welding speed V are loaded into memory (step 516).

@) Next, operate the switch SW to retract the torch T to an appropriate RO position (not shown) (step 817).

(21) Furthermore, operate switches SE and SU to clear repeating pattern number "01" and welding condition number 18 rlOJt-, and set "L". Then, operate the switch Sv to set the speed vO (step S
17■■).

c22) Then press switch ST (step 81)
8).

(23) Similarly, the computer 5 loads information on each axis corresponding to the position and orientation of the torch T controlled in step S17 into the memory. Further, the "L" command and the command speed ■ are taken into the memory (step S19).

(24) At this time, computer 5 has been using "Cand".
Contains information about Oll or rRandolj,
Since none of these are included this time, it is determined that the series of teachings up to now includes a new pattern. Then, from this series of information, the series of pattern numbers is recalculated as a position in the local coordinate system, and this is separately stored together with rRJm (rOl'') (step 520).

Please also refer to FIG. 8, which will explain this calculation below.

14 In other words, as shown in Fig. 8, welding line WL of workpiece WK
, a repeating weaving pattern Cw1 , wl , w2 . in the absolute coordinate system xyz of robot) H. C.W.
When each point position of 2s and 0w3 is taught, the coordinates are converted to a position in the local coordinate system ξηζ fixed to this workpiece WK.

That is, 8 points Cw11 Cw2 and 0w3 on the arc
Given, Cwl; 'l (Xi *)'l t ) l t
θ1! ψ1)CW2; 12(X2*y vO
2tψ2)y2)2 Cwa; 13 (X3gy3+)3yθ39ψ3
), first determine a plane containing these eight points. By substituting xL yit )i (i = 1 to 8) into the plane equation (1), the plane series a, b, and c are obtained.

Next, by substituting xi + yl + 3' into the circle equation (% (2) ) and combining equations (1) and (2), the center coordinate go (xot y
ot) Find o).

415 The radius γ is γ=1v1-rol becomes.

Next, local coordinates (ξηζ
)think of. First, set the unit vector in the direction of COCwl to 1
Assuming that all the unit vectors in the direction of CoCwIX C0CW2 are, l = (! - 樗0) / 1 - 401 (= (41 - thought o) X (gi 2 - thought o) / l
It can be written as (G1 - G0) x (I2 - ro)1 i = (x4. However, if fl< O, then f
=-4. In other words, this determines the direction of interpolation on the arc. At this time, the position conversion matrix 4 becomes i=(su,1.su)T. Therefore, 0w1 in the local coordinate system of (ri, τ, 4)
The position of the point is given by 4=q・(i − 40). This is further converted into a cylindrical coordinate system (R, e.

To convert to Z), use the following formula.

R=Iν;τ θ=1−(η/ξ) 2=ζ Regarding the torch attitude, instead of the Euler angles (θi, ψi), the unit vector 4T(Xtet )'Tt )te) where We will express it as θ ψ 7T” θ ψ 1 = α to θ, and then convert it to local coordinates as in the case of position. Assuming that T = M・iT, we will convert this iT into cylindrical coordinates. (RT, θTIZT).

With the above, we have successfully converted the eight points required for circular interpolation into the cylindrical coordinate system, but we also need information on the relative position of each point wl and w2, which expresses the weaving pattern, in the cylindrical coordinate system. Similarly, with respect to the radius RO of the circle, ΔRw = Rw −R□ΔθW=θW
−00 22w = Zw −Z6 Regarding posture ΔR7w=RTW−RTOΔθTV”θ
TV-θTO ΔZTW=ZTW-ZTO After all, these pieces of information are stored as the position of the aforementioned [series of) turn information] in the local coordinate system.

(25) Next, the operator controls the position and attitude of the heating torch at the starting point CW11 of the welding line WL2 where the operator wants to perform a similar repeating turn (step S21■)
0 (26) Further similar repeat turn number “Ol”
and set the command "C" (step 821■) 0 (nail) and then press the switch ST (step S22
).

(28) Similarly, the computer 5 takes into the memory the information of each axis corresponding to the position and orientation of the torch T controlled in step 821. In addition, "C" command,
Load the number “Ol” and command speed VO into memory (
step 828).

@) The operator controls the position and attitude of the torch to the weaving midway point Cw12 of the welding line WLLI: (step 824).

(30) Furthermore, the welding condition number "IO" and speed vl corresponding to the same repeating pattern are set (step 824■).

(31) Then press switch ST (step 52)
5).

(32) Computer 5 similarly performs step 824.
The information of each axis corresponding to the position and orientation of the torch T controlled in is loaded into the memory. In addition, "C" command 1 number "
"Ol" and "lOJ" as well as the commanded speed vl are taken into memory (step 526).

(Translation)) Similarly, after controlling the position and orientation of the torch to the position of the weaving end point CWL1 of the welding line WL2J:, by operating the switch ST, the computer 5 receives the position and orientation information of the torch T, the "C" command , number 19 "Ol" and "10" and the commanded speed Vl are taken into the memory (steps S27, S28.529).

(b) Next, operate the switch SW to retract the torch T to an appropriate position R (not shown) (step S30).

(3) Further operate switches SE and SU to select repeat pattern number "01" and welding condition number "1O".
is cleared, the rLJ command is set, and the speed VO is set by operating the switch sv (step 53).
0).

(86) Then press switch ST (step 53)
1).

(87) The computer 5 similarly captures information on each axis corresponding to the position and orientation of the torch T controlled in step S80 into the memory. Further, the "L" command and the command speed Vo are taken into the memory (step 532).

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

In Table 2, it should be understood that each piece of information about the teaching points included in the command rRJ is stored in the pattern storage section in the memory, and the other points are stored in the step storage section. . Also, the number of commands “R”, in this case “2”.
", is stored in the memory as the value of "t". Next, operate the switch SM to set the test mode, execute a known test, and correct any mistakes in the program.

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

(Support)) The mass computer 5 executes the system program stored in the step storage section in its memory.
Step information of the program to be executed next is loaded (step 5aa).

(39) It is determined whether the contents of this information include the command "C" and the repeating pattern number (r01J in this case) (step 584).

(40) If included, load step information of the program to be executed next (step 535).
).

(41) Then, it is determined whether the contents include the command "C" and the repetition pattern number "Ol" (step 886).

Prior to the above-mentioned explanation of repetition, an algorithm for executing one-circular interpolation will be explained.

22 That is, first, the reference circle C shown in FIG.

Let the radius t" Ros and the phase angle Δθ0 be the radius tR of the circular arc that is about to be executed. The tentative phase angle Δθ is Δθ=Δθr)@RO/R, and the number of divisions N in circular interpolation is Now, if θ1 and θ2 are the phase angles of Cwl and Cw2, then N=
[(θ2-θl)/Δθ+0.5] (where [ ] is a Gauss symbol). Therefore, the phase angle increment Δθ is Δθ=(θ2−01)/N. The torch angle increments are as follows:

ΔRT=(RT2 RTI)/N ΔθT=(θTe2−〇Tl)/N ΔZT=(ZT2−ZTI)/N Therefore, the interpolated points on the circumference are calculated by sequentially adding increments on the cylindrical coordinate system. It can be found by As for the location.

θ=θ+Δθ A28 Regarding the torch posture, RT = RT+ΔRT θT2θτ+ΔθT ZT = ZT + A ZT is found.

However, in practice, this information is stored in the local coordinate system (ξ,
η, ζ) must be further converted into the absolute coordinate system (X + F y)).

First, (R, θ, Z) is converted to (ξ, η, ζ). That is, regarding the position, ((Roosθ+R
a1nθ, 2), and regarding the attitude, DaT is 0, which is 9 as described above, and further conversion to the (x v y l J) system is performed. That is, zu=41・i+zu0 (with respect to position) iT= 1(
1·(t (Regarding posture) Furthermore, regarding the posture, it is necessary to convert it into Euler angles (θ, ψ), and the following calculation is performed.

θ= tan"(51T) ψ= tu (yT/XT) Sign opening 1987-bljlυb and θ The algorithm for each calculation of circular interpolation in auto mode has been explained above. This circular interpolation is
, Cv2, Cw3 may be defined and circular interpolation may be performed between CWl and Cwz, or Cw3゜CWI
, 0w2 can be determined and circular interpolation can be performed between Cwl and Cwz. In either case, the operation in the auto mode below 0, which can perform circular interpolation on a curve spanning 8 dimensions, is continued. I will explain later.

(42) In step 886, if included, calculate the number of repetitions Np (step 587). That is, first, one pitch of the weaving pattern is made the same as that during teaching, taking into account the difference in the radius of the circular arc during teaching and automatic. For this purpose, correction is performed based on the radius of the circle. Similarly to the explanation of circular interpolation, the radius of the circle when the number of pattern repetitions NpU has been taught Ros is the radius of the circle to be reproduced R1 The phase angle θ is the final point of the weaving pattern WZ (
In this case, for W2), 25 Δθ=Δθw-Ro/R Np=((θ2-01)/Δθ10.5], and the increment of the phase angle is Δθ=(θ2-01)/NP. .

(43) If not included in steps S84 and 886, the repetition ends in both cases 0 (44) Then, following step 887, position information χm(X t 'I t J +θ, <p) - First, information on the weaving starting point CW1 is loaded (step 538).

(Then, the values of W and m in the memory are set to "0" (step 889).

(46) Then calculate the repetition increment (step 5
40).

That is, for the weaving points Wl and W2, a correction is generally made based on the difference in radius for each position and orientation (for the welding line WLI, this correction coefficient is l).
, that is, for the phase angle, ΔθW=ΔθwlIRo
/R 626 Δθτw=ΔθTW 11RO/R is newly calculated and adopted.

For the radius increment and the two-axis increment, the values memorized at the time of teaching above can be used as they are. Weaving point R = Rn + ΔRw θ = θn + ΔθW Z = Zn + ΔZw and the torch posture at this time Rt = RTn + ΔRyw Zt = ``ZTn + ΔZyw θ d = eTn 100TV However, calculate n = 0 ~ NF, and convert these to the local coordinate system (ξ, η, ζ) and further to the absolute coordinate system (X * )'t''k) Conversion is performed (step 841). The algorithms for these coordinate transformations have been described above.

(48) The information expressed in these absolute coordinate systems is output as a command value (step 542).

(49) Set w = w + 1 (step 848
).

A27 (50) Determine whether w = 1 (step 544
).

(51) If so, it means that the weaving of the l pattern has been completed (If), and m=m+1 (step S 4 '5).

(52) If not in step S44, step S4
Return to 1.

(58) Then, a new circular interpolation point 9 is calculated as described above (step 546).

(54) Then, it is determined whether m = Np (step 547).

(55) If so, it is determined that all interpolation has been completed, and Vw=(m) (step 548).

(56) Then, step 54 outputs fat as a command value.
9), return to step S85.

(57) If not in step S47, w = 0
Then, the process returns to step S41 (step 850).

Thus, between points Cw1 and Cw2 on the welding line WLI,
Not only can weaving be performed repeatedly, but also weaving can be similarly performed between points Cw2 and Cw3. Also, the welding line W LLl: having a circular arc with a radius different from this point CWIII CW12
+ Cw13 as well, similar pitch weaving can be repeated. In the above description, it should be understood that movement from command point to command point is linear movement using a known linear interpolation method.

In the above-mentioned embodiment, there was no particular teaching movement at the end point of one cycle of the weaving pattern, but the end point of one cycle may also be taught. The pattern repeating pattern is not limited to weaving welding, but it is also possible to use tack welding and repeating a pattern along an arc in which welding up to point wl and non-welding at point w on the welding line.

(See FIG. 5) Furthermore, even if the robot has a coordinate system other than the rectangular coordinate system, it can be implemented as in the above embodiment by converting the coordinates to rectangular coordinates. Furthermore, the degree of freedom at the wrist of the tip of the robot is that the torch has Euler angles θ, ψ and 9
It suffices if the structure is transparent. In addition, to store the repetition information of one cycle, instead of using the information taught during teaching using the workpiece, for example, the repetition patterns are standardized into several types, and these standardized patterns are stored in advance in the local coordinate system. You may also make it memorize. This local coordinate system is not limited to a cylindrical coordinate system, but can be similarly implemented even if it is a polar coordinate system.

In addition to the above-mentioned teaching of at least eight points, circular interpolation allows continuous three-dimensional continuous curves spanning four or more points to be interpolated using circular arcs. Furthermore, in the case of only circular interpolation without repetition, N
This can be implemented by setting P=N1t=0.

Further, in all of the above embodiments, the tool serving as the end effector was a welding torch. In addition to this, for example, a cutting robot equipped with a plasma cutting torch can automatically cut pattern repeating cutting lines, a painting robot equipped with a paint gun can perform automatic painting to repeatedly paint the same pattern, and an assembly robot can perform assembly work (for example, bolt tightening). It can also be implemented in automatic assembly in which the same pattern position is repeated.

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 unique and remarkable effect in that by simply storing a pattern to be repeated in advance, this pattern can be automatically repeatedly executed on any straight line.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention, in which FIG. 1 is an overall view, FIGS. 2 and 4 are flowcharts,
FIG. 3 is an explanatory diagram of the operation. FIG. 5 is an explanatory diagram of a repeating pattern in another embodiment. RO...Robot, 5...Computer, S20.
. . 1 storage means, S4. S18,816. S2B. 826 and 829...second storage means, S40°S
41 and 842...Repetition means, T...Welding torch (processing tool). Continued from page 1 0 Inventor: Hirotoshi Yamamoto, 6-107 Takkonomachi, Nishinomiya City, ShinMaywa Industries Co., Ltd. Development Center 0 Inventor: Hisahiro Fukuoka, 6-107 Takkonomachi, Nishinomiya City, ShinMaywa Industries Co., Ltd. 0 inventions in the development center Author Takahiro Asano 6-107 Takkino-cho, Nishinomiya City ShinMaywa Industries Co., Ltd. 0 inventions in the development center Author Kengo Kuwabara 1-1 Shinmeiwa-cho, Takarazuka City ShinMaywa Industries Co., Ltd. Machinery Plant Works Inside

Claims (7)

[Claims] (1) An industrial playback robot equipped with a processing tool as an end effector, the first storage means storing local coordinate system information of a pattern to be repeated in the same manner on a certain circular arc; a second storage means for storing information on a starting point, an ending point, and one point on an extension thereof on the circular arc; a repeating means for repeating the pattern between the starting point and the ending point based on the stored information of these storage means; The industrial robot comprising: (2) The industrial robot according to claim 1, wherein the industrial robot is a Cartesian coordinate robot. (3) The industrial robot has a unique coordinate system other than a rectangular coordinate system, and includes means for converting this coordinate system into a rectangular coordinate system. The industrial robot described. Bian 2 (4) The industrial robot according to claim 1, wherein the local coordinate system is a cylindrical coordinate system. (5) The industrial robot according to claim 1, wherein the local coordinate system is a polar coordinate system. (6) The industrial robot according to claim 1, wherein the processing tool is a welding torch, and the repeating pattern is a weaving welding pattern. (7) The processing tool is a welding torch, and the repeating pattern is a tack welding pattern. An industrial robot according to claim 1.