JPS6027907A - Uniform-speed reproducing method of cp type robot - Google Patents

Abstract

PURPOSE:To put the tip of a robot in uniform reproducing operation by using the ratio of a calculated teaching speed and a set speed to obtain target position data by interpolation, and driving the robot for reproduction according to the data. CONSTITUTION:The CPU4 in a microcomputer 1 processes teaching position data according to a program stored in an ROM2 to calculate a target value. In this arithmetic processing, the teaching speed of every control cycle is calculated on the basis of new teaching position data stored in time series and target position data to calculate the speed rate of the calculated teaching speed and set speed, and this speed ratio is used to calculate the target position data by interpolation. The obtained target value signal is sent to the robot through an interface circuit I2 and the robot is driven for reproduction according to the target value data.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention allows an operator to manually move a robot along a work trajectory, and to
Every time the signal is applied intermittently (1tJ1), the taught position data corresponding to the position of each joint of the robot is imported into the storage device, and based on this taught position data, the robot is regenerated along the taught work trajectory. The so-called CP (c
This invention relates to a method for controlling the playback speed of an continuous pass type robot to a constant speed.

Compared to the so-called PTP type robots, the CP type robots 1~ can teach complicated work traces more easily, so they are suitable for painting robots 1~ where work trajectories need to be given as complex three-dimensional curves. Although it is widely used, it can also be used in welding robots, etc. as needed.

However, in the case of a CP type painting robot, for example, the robot is moved directly by human power and the robot is taught the work trajectory, so it is impossible to keep the moving speed of the painting gun completely constant, and individual differences may occur. The teaching speed fluctuates depending on factors such as skill level, and this fluctuation directly changes the playback speed. Therefore, paint spots may occur in the case of the painting ROBOSO 1-, and in the case of the welding ROPOSO I. The build-up spots are η: Signs.

Such variations in teaching speed may not be much of a problem when teaching the tip of the robot (painting gun, etc.) along a straight line, or there is a limit to human power in turning parts where the direction of movement is changed. The speed had to be slower than planned (M, this is something that can't be easily solved even with a lot of practice.

Therefore, the present invention provides a cp in which the tip of the robot moves at a constant speed during playback despite speed fluctuations during teaching.
This provides a method for controlling the speed of a solo robot.The gist of this method is to capture taught position data corresponding to each joint position at regular intervals while moving the robot along a work trajectory, and to calculate the speed based on this taught position data. CP to be played
A method for reproducing a form corobot at a constant speed includes a step of calculating a teaching speed for each control cycle based on new teaching position data and target position data written in chronological order, and calculating the teaching speed. a step of calculating the speed ratio between the taught speed and the set speed determined in the step of step 3, a step of calculating the target position data by interpolation calculation using the above speed ratio, and a step of calculating the target position data by the seven-time calculation. A step of reproducing and driving the robot according to target position data determined in the process;
The object of the present invention is to provide a constant-velocity regeneration method for a CP type corobot, which is characterized by comprising the following.

Continuing - With reference to the attached page 1, embodiments embodying the present invention will be described to provide an understanding of the present invention.

Here, FIG. 1 is an oscilloscope diagram showing the control circuit of a CP-type coating machine used in the re-keying method according to an embodiment of the present invention, and FIG. 2 is a flowchart 1 showing the steps of the regeneration method.・It is.

Typical painting robots currently known are ) 11
, a swivel table that rotates (first axis [111uθ1) around the l'tH straight axis at 1; , 1)・1iJj (second degree of freedom θ2) possible ■(
A straight arm is provided at the tip 6W of this il'F arm, and -C swing Il! is provided in the vertical plane. JJ (third degree of freedom θ
, ) is possible, and the tip of this horizontal arm has multiple degrees of freedom (θ4, θ, ), such as turning and swinging.
A tool such as a painting gun is attached to the tip of this part V1.

1- Since each degree of freedom of 01 to θ is driven by a 1lrl control circuit having the same configuration, FIG.
Only the control system for the inner water arm with these five degrees of freedom will be shown, and the others will be omitted.

In Fig. 1, numeral 1 denotes a microcomputer, which has a built-in program containing control procedures for all degrees of freedom.F-only memory (ROM) 2 and temporary memory (RAM) 3 for temporarily storing data. , an output interface circuit 12 for matching data in order to output a target value to the control system, and a human interface circuit 1 for matching data input from the control system to the microcomputer 1. and the teaching position data manually inputted from the input interface circuit II.
A central processing unit CP I calculates a target value by performing predetermined arithmetic processing on the taught position data according to a program built in the ROM 2, and sends this target value to the control system via the output interface circuit I2.
J4.

Also, the horizontal arm 9 is connected to the horizontal arm 9 via the output interface circuit I2.
The target value signal sent to the control system is converted into an analog signal by the D/Δ converter 5, and then transmitted to the servo valve 8 via the ratio illumination device 6 and amplifier 7, and drives the servo valve 8. The servo valve 8 is used to adjust the amount of oil sent to the hydraulic cylinder 1 (+) that drives the horizontal arm 9, and the horizontal arm 9 is swung by the hydraulic cylinder 10 at a swing angle θ1 for a certain period of time. It is measured by a position detector 11 consisting of a rotary encoder, resolver, etc. installed at the center of rotation of 9, and is fed back to the comparator 6. Also, during teaching work, the swing angle θ is compared as teaching position data. It is sent to the CPU 4 via the input interface circuit 1 without being fed back to the R
It is stored in AM3.

In the RAM 3, in addition to a taught position data area R7 for storing the taught position data θ1, a data number area R for storing the data number r1, and a teaching speed (2).

Record area R7 for storing speed ratio 1. area R
3. Area R4 for storing (X, n, Ym, Z,), (X
It has storage areas such as an area R6 for storing data (n, Yo, Zll) and an area R for storing target position data θ□.

Next, a teaching procedure using the above control circuit will be explained.

Prior to the teaching operation, the operator still switches a teaching-reproduction switching switch on a control panel (not shown) to the teaching side.

Then, the solenoid valve 1 inserted into the conduit connecting the conduit between the servo valve 8 and the hydraulic cylinder 10 and the oil tank
2 opens and the hydraulic cylinder 10 becomes able to freely expand and contract by external force regardless of the operation of the servo valve 8, and the horizontal arm 9 becomes swingable by the operator's own blade. The same holds true for other degrees of freedom, allowing the operator to move the coating gun along any work trajectory using the wrist.

Therefore, the operator manually moves the wrist while pressing a teaching switch provided on the wrist, and moves the paint gun along the work trajectory required for the painting job. The horizontal arm 9 is oscillated in accordance with the coating gun paste J, and the oscillation angle, that is, the taught position data θ, is transmitted from the position detector 11 to the CPU 4 through the input interface circuit 11 at every control period ΔL, for example. imported and area R of RAM3
7 are stored sequentially.

The teaching position data θt is continuously captured while the teaching switch is pressed, and the teaching position data θt, θ2, .theta. Taught position data of θ3...θ, . . . is stored. Similarly, taught position data is sequentially stored for the other four degrees of freedom.

Next, referring to the flowchart shown in FIG. 2, the procedure of the reproducing operation will be explained. Number of each step (step number)
Express it as a, b, c...

Prior to the regeneration work, the operator switches the teach-rehabilitation switch to the regeneration side, closes the solenoid valve 12, puts the hydraulic cylinder 10 in a state where it can be controlled by the servo valve 8, and moves the robot to the initial position.

When the playback start button is pressed, the teaching position data (θ1. to θ5t) corresponding to each degree of freedom at the initial position is
M 3 and use these data to perform forward coordinate transformation to obtain the rectangular coordinates (X) of the initial position.

, Y+, Z+, L+, M+, N+).

(L, M, N) are the direction cosines of the tool attached to the tip of the wrist.

Now, for the sake of a sentinel, change in rectangular coordinates excluding direction cosine is taught in order of position (in order of data number) (X+.

Yl, Z+), (X2.Yn, Z2), (X3°Y3.
Z3), -(Xn, Yn, Zn), . . . , the moving speed (teaching speed) V+ of the painting gun during teaching while proceeding from data number 1 to data number 2 is expressed by.

■ Set speed (constant) depending on the circumstances of the painting work.

Then, the speed ratio 11 is calculated as (Vo/V+).

In the present invention, the speed when moving from this initial position (n=1) to the second taught position (n=2) is the set speed V. Since the second taught position coordinates (χ2.Y2.Z2) cannot be directly used as target position data unless ■,=1, the second taught position coordinates (χ2.Y2.Z2) cannot be directly used as target position data.
Right angle IIiτ mark (X, , ', Y2'
, Z2') are determined by the following formula.

I2' = X1 + 11 (I2 Xl) Y2'
=Y1 + 11 (Y2 Yl)7J2' -
21+ It (I2 Zl) Here, the subsequent processing is divided into cases where 11 is close to 1 (the taught speed is close to the set speed) and cases where it is far.

1. Go I K) <I <K's! ! 1 Set K here to a value greater than 1, such as 1.5 (1<
It is desirable that K<2, and in particular, that K = about 1.5.

In this case, since the taught speed is close to the set speed (X, ′, Y
2', Z2') are the taught position coordinates (X, , Y.

, I2), so (X2', Y
2', Z2') may be adopted as the target position coordinates, and the target position data (θ11', 022') corresponding to (X2', Y2', z, /).

θ32′) and output this to the output interface circuit I2.
The signal is then output to the D/A converter 5, etc. Direction cosine (L2'
, X2', N,') is calculated using (θ+2', θ
The same applies to 52').

The calculation method for (θI2', 022', θ?2') is (I
2', Y2', I2'), but in order to save calculation time, it is preferable to perform the following interpolation calculation.

θ12′ −〇+++[, (θIsu θI+ )θ22
'. θ21+II(θ11-θ21)θ? 2′−θi+
After +11 (θ32 to θ31), the teaching position data (
θ13. By forward coordinate transformation from θ2, θ33), (I9
．． Y3. Z,) and the second target position coordinates (X2',
Y2', Z2') and increase the composite speed 2,'.

Then, as above, the speed ratio j2-(vo/V2')
When (1/K)<I2<K, cylinder 3 is calculated as above.
The target position data (θ13′, θ2.′, 633′) of θ −3′ −θ 12′+12(θ I3− θ 1
2') θ2)'-θll'+12(θ23-θλ2
') θS' - θ32'+12 (θ7U - θ32'), and outputs this as target position data to the D/A converter 5, etc., and performs constant-velocity playback work by positioning the robot robot in drive 1.

(1/K)<1. Continue the same procedure as long as <K.

■, Upper L and q piece In this case, the teaching speed is significantly slower than the set speed, so the second teaching position coordinate (I2゜y2.I2) cannot be adopted, and only one teaching position can be used. Jump over to the third
For the teaching position coordinates (I3, Y:l, Z:l) obtained from the th teaching position data (θ13, θ23.θ?3), the teaching speed ■1' is determined, and the setting speed ■. and speed ratio 1+'
-(Vo/V,') is calculated. If this II' is further II'≧, use the same procedure to calculate (X,,Y,,Z,)
and (X+, Y4., I4) to +1”-(V
o / ■I ”).

If the above procedure is repeated, it will eventually become I, <K, so at that point, we will move on to the processing of 4 units ■ lift gold. However, if this is repeated too many times, the real-time calculation will not be completed within the control period, so take measures such as aborting it after an appropriate number of times and sounding an alarm.

If I, / is below, the target position data (θ1z', θ2z', θ32') becomes θ52'=θu
+ 11' (θ13-θ11) θ22'=θ21
+II'(θ71-θ21)θ32'-θ3++1%(
The servo system is driven using this as the target value.

Ill, I ≦ (1/K) - In this case, the teaching speed is much faster than the set speed, so the second teaching position coordinates (X,, y.

, 22) and the first taught position coordinates (XI, Y+, Z+
), the second target position coordinates (X2', Y2', Z2') may be set at a position where the distance between the two is reduced according to the speed ratio.

Therefore, the second target position data (θ, 2'・0
22', θ3z') is 01□'-θu+11(θ, 2-θH)θz2/-
θ21+Il(θ2z-θz+)032'-θy+
+11(θ)2−θ31), and the control system is driven using this as the target value.

The thus obtained (θIZ', 022', θ72') is transformed into (X2', Y2', Z2') by 10 coordinates,
(X2, Y2, Z2) again, I+'
Calculate = (vo/vl').

Here, if plane II'≦(1/K), θ 13' - θ12 ' + I I ' (θ I
2- 〇l) ′ )023′ −〇22′ +II
′ (θ22−〇2χ′)θ3 ′ −θhz′+1
1'(θ12-θ72')
? ', θ23', θ13') are output as third target position data to the D/A converter 5, etc., and playback control is performed.

In this way, when I+>(1/K), ■,
Otherwise, continue with the steps in ■.

Next, in general terms, processing for the n-th data will be explained with reference to FIG.

As mentioned above, in steps a and b, the taught position data of the initial position is taken out and the taught position coordinates (XI, Y, , Z
, ), and then performs the calculation n=n+1, stores the value of n in the RAM area R1, and stores the new n-th taught position data as θ in the RAM3. from area R7, and its teaching position coordinates (xi, Y, z
n) by forward coordinate transformation (d).

Next, in step e, the previously set target position data (
Convenience - Determine the taught speed ■Yl using the target position coordinates (Xm, Ym, Z, n) obtained by forward coordinate transformation of θ□ (represented by θ□), and further calculate the speed ratio ■, = ( ■o/
■ Add n).

The following two judgment steps g and h are I, ≧K, ■, ≦(
1/K), and if (1/K)<1+<K (i.e., the process in 1. above), both judgments are NO and in step i, the target value θr+ ' = Om + 1
1 (θn-0,) is calculated for each degree of freedom and output for each control period (j).

Then θ. ' is stored in the θ□ area R6 of the RAM 3 as θ□ (step k) for step e of calculating the next vr+, and further as n = n -1-1 (step I
! , ) Proceed to determination step m. In step m, it is determined whether or not n is the last data number. If Yes, the process ends; if NO, the target position data (θ1m to θ
-m) to obtain the target position coordinates (χ, , Ym, Zm). The process returns to step d via step n.

In the case of Yes in the determination step g (that is, the process of H), steps i, j, and k are omitted, and in step l, n=n+1 is set, and the process of skipping data by one is performed.

If it is determined in step h that ≦(1/K), the process returns to step e through steps +/, j/, k/, and n/ similar to steps i, j, k, and n.

In the above embodiment, a case has been described in which joint angles are employed as the teaching position data stored in the RAM 3, but depending on the case, this may be replaced with the cylinder length of the hydraulic cylinder, or it may be obtained by converting from the joint angles or cylinder lengths. It may also be stored in orthogonal coordinate values (X, Y, Z, L, M, N). Note that it is preferable to adopt buffered starting and stopping, which gradually increases or decelerates the speed, instead of performing constant speed control during a certain period (or time) at the time of starting and stopping. Further, the servo valve and hydraulic cylinder as the driving IJt source are just examples, and when used in an atmosphere without the danger of explosion, they can be replaced with an electric motor or the like.

As described above, the present invention captures taught position data corresponding to each joint position at regular intervals while moving the robot along the work trajectory, and reproduces the CP type robot at a constant speed based on this taught position data. In the method of
1. Calculating the taught speed for each control cycle based on new taught position data and target position data stored in chronological order; ] - a step of calculating the speed ratio between the taught speed and the set speed obtained in the step of calculating the taught speed, and a step of calculating target position data by interpolation calculation using the speed ratio,
This is a constant-velocity regeneration method for a CP type co-robot, which is characterized by comprising the step of regenerating and driving the robot according to the target position data determined in the step of calculating the target position data by the interpolation calculation. This eliminates paint spots on robots and build-up spots on welding robots, and enables constant speed regeneration of the robot tip regardless of the skill level of the operator.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a control circuit of a CP type painting robot used in a recycling method according to an embodiment of the present invention, and FIG. 2 is a flowchart showing the procedure of the recycling method. (Explanation of symbols) ■... Microcomputer 2... ROM 3... RAM 4... CPU 5... D/A converter 6... Comparator 8... Servo valve 9...・Horizontal arm 1o...Hydraulic cylinder 11...
・Position detector a=n, i'~n'...Step number ■n...Teaching speed θ. ′...Target position data. Applicant Kobe Steel Corporation Representative Patent Attorney Takeo Honjo

Claims (1)

[Claims] l. Constant 1fi while moving the robot along the work trajectory.
(1) In the method of generating a robot at a constant speed, the taught position data corresponding to each joint position is taken in and reproduced based on this taught position data. (2) Calculating the speed ratio between the taught speed determined in (1) and the set speed based on the new taught position data and target position data that have been updated. (3) calculating target position data by 1 ili calculation using the speed ratio; and (4) regenerating and driving the robot according to the target position data determined in (3). A method for reproducing a CP type corobot at constant speed, which is characterized by the following. 2. If the speed ratio determined in (2) above is above the specified range, proceed to (1) without going through steps (3) and (4).
Returning to the step of (1) and (2), the steps (1) and (2) are repeated until the speed ratio falls within the predetermined range or falls below the predetermined range. A constant speed regeneration method for a CP type robot. 3. If the speed ratio determined in (2) above is below the specified range, proceed to steps (3) and (4), and then proceed to step (2) without going through step (1). A constant-velocity regeneration method for a CP type corobot according to claim 1, in which the process is returned to the original process.