JPH0241879A - Correction of position for industrial robot - Google Patents

Abstract

PURPOSE:To surely position at a teaching point despite of the thermal deformation of the arm of each shaft by correcting the arm length by finding the elongation of the arm accompanied by a temp. rise and calculating the movement of each shaft based on teaching positional data and a corrected arm present length. CONSTITUTION:On the robot arm of each shaft of an arm part temp. detection means P1 - P3 detecting the temp. of this robot arm are provided. The present length of each robot arm is found by a CPU 101 from the temp. detected by each temp. detection means P1 - P3, the movement of each shaft is calculated based on teached positional data and the present length of each robot arm and each shaft is driven. Consequently, the robot tip can surely be positioned at the teaching point without reducing the position repeating accuracy of the robot itself even in case of a thermal deformation being caused on the arm of each shaft.

Description

[Detailed description of the invention] Industrial use demarcation The present invention relates to 11 position correction equations for industrial robots.

In conventional technical industrial robots, the drive control for the arm of each axis is usually based on the taught position T and the pre-stored arm length of each axis. This is done by using a servo motor to drive the movement m.

Problems to be Solved by the Invention However, in conventional industrial robots, the effects of thermal deformation on the positioning accuracy of the robot body, especially the arms of each axis, on J3 have not been taken into consideration.
Motors, brake gears, and reducers.

For industrial use such as end effector solenoid valves [1] If thermal deformation occurs in the arm of each axis due to the heating element in the hot spot or the influence of outside temperature, etc., the difference between the actual arm length and the arm length stored in advance However, there was a problem in that the repeatability of the arm position was reduced.

In particular, the amount of heat emitted from the photothermal element in an industrial robot (1) differs depending on the operating cycle of the robot 1. For robots with long drive times (such as brakes, etc.), the average amount of heat generated by 1 (Nykle) increases, and in the 1+Nykle robot operation where these heating elements have a long rest time, the average amount of heat generated decreases. The length of heat generated differs depending on the dynamics of the recycle.As a result, the length of each arm also becomes a hole.Also, depending on the placement position of the heating element, the length of the arm affected by the heat generated by the heating element varies. will also be different.

In conventional industrial robots, the decrease in positional cyclic viscosity due to thermal deformation of the arm was insignificant compared to the positioning error of the robot itself. Deterioration in position repeatability due to deformation has become a major problem.

Therefore, an object of the present invention is to provide an industrial robot body, in particular,
An object of the present invention is to provide a position 11ff correction method for an industrial robot that can reliably position a taught point without deteriorating position repeatability even when thermal deformation occurs in the arms of each axis.

Means for Solving the Problems In order to achieve the above object, the first invention provides at least one cobot arm for each axis of the arm section.
A temperature detection means for detecting the temperature of the arm is provided, and the current length of each robot arm is determined from the temperature detected by the temperature detection means and taught (based on the zero position data and the current length of each robot arm). The movement of each axis was determined and each axis was driven.

In the second invention, the squared current average value of the drive current of each servo motor that drives each axis from the start of the regenerative operation is detected every predetermined period, and each robot 7 is - Find the temperature rise that brings each arm into an equilibrium state, and calculate the total temperature rise of each arm at a predetermined period by adding the mean square of each servo motor to the above 1-7 temperature according to Haku Ichiryu for each arm. The temperature rise delay is corrected based on the total temperature rise and the time from the start of the regeneration operation, and the elongation due to the temperature rise of each arm is determined every predetermined period, and the elongation fil is corrected to the arm condition of each arm for regeneration. The amount of movement of each axis during operation was calculated and each axis was driven.

Effect According to the first invention, J3 has the following characteristics:
The temperature of the robot arm of each axis is detected by the temperature detection means, and the current length of the robot arm of each axis is determined from the temperature of each robot arm, taking into account the amount of thermal deformation.

The drive control for the robot arm of each axis is based on the taught position data and the current configuration of the robot arm of each axis, and the amount of movement (rotation angle) of each axis angle is determined. This is done by driving each axis.

Moreover, in the second invention, the re! J',
? Find the average squared current value of the drive current for each servo Tanabata from the start of the M rotation, and use this average squared current value to find the temperature rise that will bring each arm into a temperature equilibrium state, and then calculate the temperature for each motor for each arm. Above due to current? ? The temperature increase due to the temperature of the hot water is determined, and the elongation m due to the temperature increase of each arm is determined by correcting the temperature and stomach retention. This process of calculating the amount of elongation is performed and stored at predetermined intervals, and during regeneration operation, the amount of elongation of each arm at the current moment is corrected to the arm length of each arm, and the amount of movement of each axis ( axis of rotation) and drive each axis.

As a result, when dedicating the amount of movement for each axis angle, the arm length of each axis takes into consideration the amount of thermal deformation! Since the positioning position determined by standing up is used, it is possible to reliably position the water teaching position regardless of the temperature of the arm of each axis and regardless of the amount of striking or thermal deformation.

Embodiment FIG. 1 is a block diagram of the main parts of an industrial robot according to a first embodiment of the present invention.

The numerical control device 100 as a control i(l device) that controls the robot body 1 includes a central processing unit (hereinafter referred to as cPU) 1o1, and the CPU 1011.: l:L,
ROM102. RAM103. non-volatile RAM 104,
Teaching operation panel 105. Operation panel 10 equipped with CRTR7 display
6. Axial control tII device 107. The input/output circuit 109 is connected to the bus 11
1.

A control program for the CPU 101 (7) is stored in the ROM 102, and a teaching operation 1105 is stored in the nonvolatile RAM 104.
Various teaching f such as the teaching position inputted from the operation panel 106
- data, each call setting data input from the operation panel 106, etc. are stored. Also, RAM 103 is CPLJl
It is used to temporarily store various data such as OL's Enshucho Sung Dynasty.

The axis controller 107 is connected to a servo amplifier 108 that drives the 11-vo motor of each axis of the robot body 1. In this embodiment, a software 1-no-vo system is adopted, and current commands are sent to the servo amplifier 108 of each axis. It is designed to output a value, that is, a torque command value, and performs revo control by inputting a feedback signal from a valve coder attached to the servoator of each wheel to drive the revo motor of each axis. This embodiment shows an example of a six-axis robot, with three axes on the arm and three axes on the wrist. @ arm.

They are called the second @ arm and the third axis arm.

Note that the above configuration and control method are the same as those of conventional industrial robots, so detailed explanations will be omitted.

Further, in this first embodiment, in order to apply the method of the present invention, each of the arms of the first to third axes is provided with temperature detection means (for example, a thermal lightning pair) Pl.

P2. P3 is provided, and the output of each temperature detection means is Δ/D
After being converted into a digital signal via the converter 110, it is input to the input/output circuit 109, and by the action of the CPU 101, the current temperature of the arm of each axis T1. T
2. T3 is written into the RAM 103. Note that other actuators, sensors, etc. provided in the robot body 1 are also connected to the input/output circuit 109, but are omitted in the drawing.

Therefore, in the first embodiment of the present invention, the current temperatures TI, T2 . From D3, the linear expansion coefficient α of the arm of each axis and the lead of A1 of each axis are obtained as follows:
．． The current length L1' of each 5111 arm based on 13
, L2', 13' J: It is a sea urchin,
Therefore, in this first embodiment, the tape TBI as shown in FIG.
It is set in. The table TBI has the reference length L1.12°L3 of the arm of each axis and the current length 11', L2'.
, 13' are stored. In addition, the reference length L1 of the arm of each axis. L2. L3 is measured in advance by the manufacturer and stored in the table TBI above.
The temperature To at the time of dimension measurement is also memorized at the same time. Further, in this embodiment, since the arms of each axis are formed of the same material, the values of the linear expansion coefficients α are the same.

The arm length calculation method in the first embodiment will be described below along with the 70-day arm length calculation process (FIG. 2) that the CPtJ 101 executes at predetermined intervals.

In the arm mounting process, the CPU 1o1 first sets the counter 1 to 0 (step S1), increments it (step 82), and then sets the first axis stored in the RAM 103 based on the value of the counter i. Reads the current temperature Ti of the arm and the reference length 1i of the i-th arm 11 stored in the table TB1 (step S3), and
P 艮Li.

The following equation (1) is performed using the linear expansion coefficient α, the current wet mark Ti, and the temperature ■0 at the time of reference length measurement to find the current length li of the arm of the axis (step S4). ), the current length i' is put into a predetermined position of the dimple TB1 by -11 (step 85).

Li'=l-i・[1+α(T 1-To))・
...(1) Next, check whether the (direction) of counter i has reached 3, that is, the current length L1' of the arm of the first axis (i=
1).

The current length of the second @ arm is 2' (i=2), and the third +
Determine the current length L3' (1=3) of the 7-m of I+I+ and determine whether the process of SP inserting it into the predetermined position of the L T cable TBI has been completed (Step 86), and if the value of the counter i is 3. has not been reached (J), return to step S2, increment the counter i, and then perform the same operation as above to calculate the current length l-1' of the arm of the first axis. and the current length of the arm is 1− j +
4- Repeat the process of writing the
0 In this way, the current length of the 11111th arm is 1'
, 7th axis current fc12', 31st IIll
Take out the current length of arm 1-3' g7 and put it on table TE.
31 to the specified location] 11! is completed in pan direction, and when it is determined that the (direction) of force 1 synta i has reached 3 in step S6, the 7-m Nagaide process in which J31 is pressed in the 111I cycle is completed.

Thereafter, arm good output processing is executed in the same manner as above at every predetermined period, and the current length of each axis arm is 11 '12', 13
' will be updated and stored in the table TBI at a predetermined period f7i.

On the other hand, the process for moving the arms of the first to third axes, that is, determining the rotation angles for movement to the taught position iδ, is performed from the teaching data and the arm rings of each axis (rotation angles), as in the past. ) is tjFl, and a movement command for each axis is output based on the result of the operation ().The arm ring of each axis used in this calculation process is updated and stored in the table B1 at predetermined intervals. Current length of sleeve arm L1', L2', L3'
Because of the use of There is no loss of accuracy.

Note that the temperature detection means P1. mounted on the arm of each axis. P2
．． It is desirable to install P3 at a position where the average temperature of the arm of each axis is detected, but one stage of multiple temperature sensors is installed on the arm of each axis, and the temperature detected by each temperature detection means is Average the temperature of each axis arm! )
It is also possible to have it released. Also, arms other than the arm, the arm of the arm, and the arm of the wrist should also be provided with a M1 degree detection stage to correct the arm F of these arms, but these arm rings are small. : Since it is less affected by temperature, C is omitted in the wood example.

Next, the second embodiment will be explained. In this second embodiment, in advance, the temperature range in which the robot body 1 can operate is divided into a plurality of temperature ranges υ1, and a temperature range C corresponding to each temperature range is set.
Arm ring 11' of the first shaft, arm ring 1-2' of the second shaft
, set the dimple TB2 (Fig. 5) in which the arm ring 1-3' of the third qall is stored in the non-volatile RAM 104.
J and d3 and the temperature of each axis arm is 1 and T1. T2. T3
The current length of each axis arm is selected from the table TB2 based on the table TB2. The hardware configuration of this embodiment is the same as that of the first embodiment, but
This embodiment differs from the first embodiment in that the nonvolatile RAM 104 is provided with the table TB2 described above, and that it is not necessary to provide an area on the table TB1 to record the reference length of each axis arm. Note that the temperature ranges shown in table TB2 are represented by the upper limit of temperature in each temperature range.For example, if the temperature fi! If the step width of the temperature range is 5°C, the upper limit of humidity t1 at J3 in Fig. 5 is 5°C, which represents the temperature range 0°C to 5°C. The arm ring L of the first axis corresponding to the area (
1,1>, the arm ring L (2,1) of the second axis, and the arm ring L (3°1) of the third axis are the intermediate humidity G-J in the temperature range, for example, 2. The actual length at around 5° C. is measured experimentally or determined according to the terminology, and the actual length is stored in advance and J3<. Similarly, the temperature upper limit t, t3...1. ...Set tIIl (in this case, m=12), memorize the arm ring of each axis corresponding to the intermediate temperature of each heating region, and set a3<
.

Hereinafter, the arm length p calculation method in J3 in the second embodiment will be explained along with a flowchart (FIG. 3) of the arm length calculation process executed by the CPtJ 101 at predetermined intervals.

In the arm length calculation process, the CPU 101 first sets the counter fJ5 and the counter j to O (step S11, step 512), increments the counter i (step 513), and then increments the value of the counter i by 3J. Then, the current temperature Ti of the arm of the first axis stored in the RAM 103 is read (step 514), and then the temperature is read from the table TB2 based on the first shift of the J counter j that incremented the counter j. The upper limit value is read (step 516), and it is determined whether the current temperature of the first arm is less than or equal to the temperature upper limit value t, that is, the current temperature IFJTi of the first axis arm is equal to or lower than the temperature upper limit value t. It is determined whether the temperature is included in the temperature range represented by (step 517). Current temperature Tf of arm of 1st INl
If the temperature range is not included in the temperature range represented by S'IQ degree upper limit value t, the process returns to step S15, the counter j is incremented, and the temperature upper limit value is determined from table TB2 based on the incremented value of counter j. t
(step 816), and determines whether the current temperature Ti of the arm of the first axis is equal to or less than the temperature upper limit value t, that is, the current temperature Ti of the arm of the i-th axis is represented by the temperature upper limit value tj. It is determined again whether or not the temperature is within the specified temperature range (step 517). Hereafter, in the same way, step 8
Repeat the loop-like process from step 15 to step 817.
When a temperature range in which the current temperature 7i of the first axis arm is equal to or lower than the temperature upper limit t is detected, the current arm length corresponding to the current temperature T1 of the 1st II 41 arm is indicated by counters i and j. The arm length L(i, j) is written at a predetermined position on the table TB1 as the current arm length L i / of the first axis (step 818).

Next, check whether the value of counter i has reached 3, that is,
The current length of the arm of the 1st 'kll' is 1', the current length of the arm of the 2nd axis is 2', the current length of the arm of the 31st NI is L3'
Step 519) is performed to determine whether the process of obtaining and writing the value to a predetermined position in table TBI has been completed, and if the value of counter i has not reached 3 (), step 81 is performed.
After returning to step 2 and setting counter j to O again (step 512), incrementing counter 1 to 1 (step 513), calculate the current length L + L of the arm of the first axis in the same manner as above, The current length L I+ of the arm is written at a predetermined position on the table TB1.

In this way, the current position L1' of the arm of the first axis, the second axis
The current length of the axis arm L2', the current length L of the third axis arm
3' and writing it into a predetermined position in the table TB1 is completed, and when it is determined in step S19 that the value of the counter i has reached 3, the arm length calculation process in this processing cycle is ended. .

Thereafter, the arm length calculation process is executed in the same manner as above at every predetermined period, and the current length L1'L2'L of each axis arm is calculated.
3' is updated and stored at a predetermined position in the table TB1 every predetermined period.

Regarding the movement mQ output processing to the teaching position, it is performed in the same manner as in the first embodiment described above, and in this embodiment, as in the first embodiment, each axis is Regardless of the temperature of the arm, positioning to the taught position can be performed reliably, and position repeatability does not deteriorate due to thermal deformation.

As described above, in this embodiment, based on the current i1T i of each axis arm, The current arm length of each axis is determined. Therefore, when creating the table TB2 and experimentally measuring the arm length of each axis corresponding to each temperature range, temperature detection means 1]1. P2
．． After attaching P3, the robot body 1 is driven and the temperature rise caused by the heat generated by the levers, brakes, end effectors, etc. of each axis is detected by the temperature detecting means P1.P3. P2
．． In addition to actually detecting by P3, the arm length of each axis at each detected temperature is actually measured, and data to be set in table TB2 is obtained based on the detected temperature and the actual measured value of the arm length of each axis. This makes it possible to obtain data that approximates actual usage conditions, and further improves reliability when determining the current length of each axis arm from the temperature of each axis arm during robot operation.

Next, a third embodiment of the present invention will be described.

In this third embodiment, temperature detection means P1. f)2. P3 is not explained, but the point that the arm ring of each arm is determined from the total drive current of each axis of the heating element is the above-mentioned point 1. This is different from the second embodiment. So,
In this third embodiment, the influence on the arm ring due to the heat generated by the brake, reducer, solenoid valve, etc. is minimal;
Among the Tanabata rings that drive each axis, the arm rings are the T-taters that drive the arms of the arms (first and second, similar to the second embodiment).
It is assumed that the effect is caused by the heat generated by the motor that drives the arm of the third axis. However, this method can also be applied to brake solenoid valves and the like as long as they generate heat due to energization.

In addition, external disturbances such as outside temperature and outside air flow were ignored, and the robot was in perfect thermal equilibrium with the outside before operating.

First, the principle of operation of this third embodiment will be briefly explained.

The arm of the 1st axis is arm △, the arm of the 2nd axis is arm B
, the arm of the third axis is referred to as arm C, the motors driving each arm Δ to C are Ma, Mb, and Mc, and the driving currents are i,', and i. Soshia'
bc, the drive current of motor Ma of arm A is 1. ΔTAa is the temperature increase due to heat generation due to the drive current ib of motor Mb, ΔTAb is the upper limit temperature due to heat generation due to the drive current ib of motor Mb, and ΔTAC is the temperature rise due to heat generation due to the drive current 1° of motor Mb. The upper W temperature due to the drive currents 0, 1b, and i are ΔTl3a, ΔTBb, ΔTBc, the drive current of arm C is 18°, and the temperature increase due to ic is ΔTCa, ΔTCb.

ΔTCC, and these −HIFA temperatures are shown in Figure 7.JJ:
Assuming that there is a delay in temperature rise with a predetermined time constant, heat settling time To, from the start of driving in the evening, this heat settling time TO'2 is experimentally determined, and each is calculated as the overnight drive current. squared 1a-i (depending on the size of H, the rising temperature in the equilibrium state where the temperature of each arm A-C has stopped (
When the temperature rises to Rib Elm-1, the upper temperature is) ΔTA
ta~ΔdAC1ΔTBa~ΔTBc, ΔTCa~ΔT
Determine Cc experimentally, store it in a table, and calculate the driving current of -9Ma-MC for each time after driving the robot.
Find the average value of the multiplied current, and use the average value of the current to determine the temperature of each arm from the table above.
ΔDC2ΔTBa~Δr [3C, ΔTCa~ΔTC
Find c. For example, arm 8 is ΔrAa when driven by [-ta Ma, ΔTAb when driven by -E-ta Mb,
If it is determined from the table that there is a temperature increase of 4 above ΔTAc due to the drive of motor MC, the temperature increase to the arm is calculated by adding these temperature increases, ΔT A a + ΔTAb +
Temperature of ΔTAC] Assuming that there are two arms, the extension of the arm ring to the arm due to this, ΔL8, is determined from the following equation.

ΔTΔa+ΔTAb+ΔTAc>
... (2) In the above equation (2), K is a proportionality constant, which is obtained by experimentally correcting the coefficient of linear thermal expansion and the arm ring.

” The extension Δ of the arm ring to the arm determined by the second equation (2)
1-A' is the elongation b in the flat state where the upper temperature limit has stopped, so considering the thermal settling time as shown in Fig. 7, the temperature increase 51; ′
Perform E to find the extension Δ of the arm ring of arm Δ.

T.

To L△= To L△' (1-e) ... (3
) Also, the arm ring extension Δ1-B of arms B and C.

Δi Ct, is determined similarly. This elongation indicates the amount of elongation from the arm ring when the teaching point is taught to the robot.
Correct the height C to the arm ring so that the rotating parts of each axis are set to 0. This makes it possible to correct the elongation of the arm ring due to temperature rise and accurately position the robot at the taught position.

Therefore, a drive current is applied to each motor Ma-Mc sequentially in advance, and the temperature at the top of arms 8 to C according to the square of the drive current (temperature - F is the upper limit temperature when the back stops and subulates). ) as a table and the tilt-induced RΔM10
Store in 4.

FIG. 6 shows an example of a daple 10a showing the correspondence of 46 teeth Aa to ΔTCa on the temperature of each arm A to C with respect to the square of the motor current 1a of the motor Ma, and in FIG. 6, ΔTAa1 to ΔTAao are , the temperature at which the arm 8 heats up is shown by the six values of the square iH of the drive current of the motor Ma, and similarly, ΔT8a ~ ΔTBa, ΔTCa1
~ΔTCa.

n stores the temperature upper limit of each arm Δ to C with respect to the square i1 of the motor current of arm B, arm ch<7-1ta Ma, and similarly to this FIG. 6, motor Mb, M
Temperature of each arm for each motor current ib, ic of c - [stomach ΔTΔb.

ΔTBb, ΔTCb and ΔTAC, ΔTBC.

ΔTCC is created as daples 10b and 10c (not shown) and stored in M104 as a non-volatile 1.

Then, when the robot starts regeneration operation after teaching the robot motion, the CPU 101 performs the process shown in FIG. The robot will perform regeneration operation after correction.

When the regeneration operation is started, the CPU 101 starts a timer and performs the process shown in FIG. 8 at predetermined intervals. On the other hand, the CPU for servo control in the axis controller 107 outputs the square of the command current (command torque) to each motor for each processing cycle m to the CPU 101 and the CPU for servo provided in the axis controller 107.
J1 is written into the shared RAM that can be accessed from the PU, and the servo CPU writes the average value of the written square current.

The CPU 101 writes a register R to the shared RAM at predetermined synchronization intervals (step S1) and adds each squared current average value.
a, Rb, and Rc (step 82). Note that registers Ra-Rc are initialized at the start of regeneration operation and set to "0".
” has been rated 1~.

Next, divide the value of each register Ra-RC by the value of the timer to obtain the squared current average value i a2 * i b2 * i c2 of each motor from the start of regeneration operation to the present time (
Step 83). This squared current average value ia.

b, each arm upper limit temperature ΔTAa to ΔTAC for ic
1ΔTBF1~ΔTBC, ΔT Ca−・ΔTCC as tape/L/10 a in nonvolatile RAM 104.

10b and 10c (step 84).

Add the upper limit temperature due to the current of each motor obtained by adding Δ
TAa+ΔTAb+ΔDC1ΔTBa ΔT B b
−1−ΔTBc, ΔTCa+ΔTCb +ΔTC
C), multiply the experimentally determined proportionality constant by 1 to 3,
The extension of each arm ΔLΔ', ΔLB'ΔLC' is determined (step 85>).

Next, the extensions ΔLΔ, ΔLB, and ΔLC of the arm at the current time when the thermal settling time has elapsed are determined by performing the next temperature range delay correction (step 86).

ΔLA=ΔmA'(1-e'') ΔLB=To 8 LB (1-elo) To LC- To LC' (1-elo) Note that t is the time measured by a timer from the start of the regeneration operation to the present time.

The elongation of each arm obtained in this way ωΔLA, Δ1−B, Δ
iC is the current ni1 provided in the non-volatile RAM 104.
The amount of expansion is re-stored at the address location (step 87).

The above process is performed at a predetermined period ffi until the regeneration operation is completed, and the current extension of each arm is memorized. When driving one cobot arm, the arm length of each arm at the time of teaching is set to the above-mentioned extension? ΔmA to Δl-c are added and corrected, the rotation angle of each axis is determined, and [1 bot is driven].

In the above embodiment, the temperature rise of each arm ΔTAa to ΔTAc, ΔTBa to ΔTBc, Δ
Although TCa~ΔTCc was calculated, Tables 10a and 10b
, 10c are provided, and f is the lower average value or average current of the driving current of each arm, and from this squared current average value or average current, the temperature increase due to one total current for each arm is determined. Δ-F△a-・ΔTAc, ΔTBa~ΔTBC, ΔT
Experimentally find the Ji calculation j℃ to find Ca~ΔTCC,
The temperature rise of each arm may be determined using this formula.

In addition, in the above embodiment, the amount of extension of the arm length was calculated and calculated by correcting the temperature rise delay in step S6, but depending on the value of time t, the value of 1-8" The value of (1-elo) is read out from the table according to the time from the start of the regeneration operation, which is 81 o'clock on the timer. ΔLB', Δ1-
Multiplying C', the extension is Δ, ΔLB, Δ1. - You may also find C.

In this third embodiment, the first. Unlike the second embodiment, the method does not directly detect the arm temperature I port, so
In cases where it is difficult to directly detect the temperature, correction is possible. Further, since a sensor for directly detecting temperature is not required, the structure can be made inexpensive. Also,
It can be applied to existing robots by simply changing the software.

Effects of the Invention The present invention calculates the extension of the arm as the temperature rises, corrects the arm length, and adjusts the movement of each axis based on the taught position data and the corrected current length of one cobot arm for each axis. is calculated, so even if thermal deformation occurs in the arm of each axis, positioning can be reliably performed at the taught point without lowering the repeatability.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of an industrial robot according to an embodiment of the present invention, and FIG. 2 is a block diagram of an industrial robot according to an embodiment of the present invention. 1 3rd
The figure is a flowchart showing the arm length calculation method in the second embodiment, Figure 4 is a conceptual diagram showing the table TBI adopted in the first and second embodiments, and Figure 5 is a diagram adopted in the second embodiment. FIG. 6 is a conceptual diagram showing the table TB2, which is a table TB2 shown in FIG. Figure 7 is an explanatory diagram explaining the thermal settling time, Figure 8
The figure is a flowchart of the process for determining the arm extension in the third embodiment. DESCRIPTION OF SYMBOLS 1... Industrial robot 1-main body, 100... Numerical control device, 101... Central processing unit line, 102... RO
M, 103...RAM, 104...Nonvolatile RAM
, 105... teaching operation panel, 106... operation panel, 10
7... Axis controller, 108... Liebo amplifier, 109
...Input/output circuit, 110...△/D converter, 111
...Bus, Pl, l'2P3...Temperature detection means. Figure 2 Patent Applicant Happuk Stock Exchange Arrival District No. 1

Claims (2)

[Claims] (1) In a control system for an industrial robot, a temperature detection means for detecting the temperature of the robot arm is provided at least on each axis of the robot arm, and the current temperature of each robot arm is determined from the temperature detected by the temperature detection means. A position correction method for industrial robots that calculates the length, calculates the amount of movement of each axis based on the taught position data and the current length of each robot arm, and drives each axis. (2) In the control method of industrial robots, the drive current of each servo motor that drives each axis is regenerated from the start of operation.
The average value of the multiplicative current is detected every predetermined period, and each of the obtained 2
Find the upper limit temperature at which each robot arm reaches an equilibrium state based on the average squared current value, and add the above temperature rise due to the average squared current value of each servo motor for each arm to obtain the total temperature rise for each arm. Calculate every predetermined cycle period, correct the temperature rise delay based on the total temperature rise and the time from the start of regeneration operation, calculate the elongation amount due to the temperature rise of each arm every predetermined cycle, and correct the elongation amount to the arm length of each arm. A position correction method for industrial robots that calculates the amount of movement of each axis during regenerative operation and drives each axis.