JPH10180662A - Industrial robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform breaking-in or warming up by measuring a current supplied to a motor, calculating a current effective value for the current and deciding a reproducing speed according the calculated current effective value as occasion demands in a controller. SOLUTION: A control unit 22 reads various programs stored in an external storage device 23, calculates conditions for breaking-in or warming up from various bits of information obtained from the various programs and a servo amplifier 28 by operation and outputs a command value to the servo amplifier 28 based on the result of this calculation. The servo amplifier 28 supplies a current to a motor 20 to drive the same and detects the current value of the motor 20 and outputs this to the control unit 22. The control unit 22 then calculates a current effective value from the detected current value and controls the motor 20 to prevent its overloading based on the current effective value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial robot such as a sealing robot and a painting robot, and more particularly to an industrial robot capable of efficiently performing warm-up operation and running-in operation.

[0002]

2. Description of the Related Art An industrial robot usually has a manipulator having arm and hand functions. Immediately after this manipulator is manufactured, since the mechanical parts such as the speed reducer are not rubbed, the sliding resistance is large and the basic performance (dynamic characteristics) cannot be satisfied. In addition, even when the industrial robot is started, viscous resistance of grease or the like increases due to a low temperature or the like, so that the basic performance cannot be satisfied. Therefore, a break-in operation is generally performed when manufacturing a manipulator of an industrial robot, and a warm-up operation is generally performed when starting the industrial robot.

Conventionally, the running-in operation and the warm-up operation have been performed by using a dedicated program (teaching data) for the running-in operation and the warm-up operation, or by using a program (teaching data) for operating the line. The operation was performed at a speed lower than the operation speed. In addition, the end determination is performed by setting an end time in advance and determining whether the running-in operation or the warm-up operation has been performed up to the time, or the operator can determine the operation status of the manipulator and the operation time. Or was judged as.

[0004]

The conventional break-in operation and warm-up operation are performed by regenerating at a speed lower than the normal operation speed. It costs. If the operating speed of the motor is increased while the current limit value is kept constant in order to shorten the running-in operation time and the warm-up operation time, the above-mentioned sliding resistance and viscous resistance are large, and if the motor capacity is small, it is excessive. In some cases, the trajectory of the manipulator was changed (shifted) due to a load, and the running speed was increased to make it impossible to perform a running-in operation or a warm-up operation at a normal operating speed.

Conventionally, the running-in operation and the warm-up operation cannot be performed in consideration of factors such as individual differences between the manufactured industrial robots and the temperature during the warm-up operation. For this reason, with respect to the running-in operation and the warming-up operation, some bad conditions (resistance (load) changes due to individual differences between robots, temperature, etc.) are assumed, and the operating time is lengthened to provide a margin. There is a need. Therefore, this also contributes to prolonging the operation time.

[0006] Further, as described above, the end determination of the running-in operation or the warm-up operation is performed by setting an end time in advance and determining whether or not the running-in operation or the warm-up operation has been performed up to the above-mentioned time. However, in some cases, the running-in operation and the warm-up operation were insufficient because the operating condition and operating time of the manipulator were used as judgment materials. There was a problem that would occur.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an industrial robot that can efficiently perform a break-in operation and a warm-up operation.

[0008]

According to a first aspect of the present invention, there is provided a manipulator having at least one shaft, the shaft being driven by a motor, and a control for controlling the motor. In an industrial robot including a device, a current effective value calculating means for measuring a current flowing through the motor to the control device and obtaining a current effective value of the current, and a current effective value calculated by the current effective value calculating means And a playback speed determining means for determining a playback speed at any time according to the condition. According to a second aspect of the present invention, there is provided the industrial robot according to the first aspect, wherein the warm-up operation regeneration speed at the time of starting the robot is determined at any time at the regeneration speed determined by the regeneration speed determining means. It is characterized by comprising determining means. According to a third aspect of the present invention, in the industrial robot according to the first aspect, a break-in operation playback speed determining unit that determines a break-in operation playback speed at the time of manufacturing the robot at any time at the playback speed determined by the playback speed determination unit. It is characterized by having. According to a fourth aspect of the present invention, there is provided an industrial robot having at least one axis, the axis being driven by a motor, and a control device for controlling the motor, wherein the control device flows to the motor. A current effective value calculating unit that measures a current and obtains a current effective value of the current; and a current limit value determining unit that determines a current limit value of the motor as needed based on the current effective value calculated by the current effective value calculating unit. Means. According to a fifth aspect of the present invention, in the industrial robot according to the fourth aspect, the current limit value for the warm-up operation at the time of starting the robot is determined as needed based on the current limit value determined by the current limit value determining means. It is characterized by comprising machine operating current limit value determining means. According to a sixth aspect of the present invention, in the industrial robot according to the fourth aspect, the break-in operation in which the current limit value of the break-in operation at the time of manufacturing the robot is determined as needed based on the current limit value determined by the current limit value determining means. It is characterized by comprising a current limit value determining means. Also,
The industrial robot according to claim 2 or 5,
A warm-up operation end determination unit that determines the end of the warm-up operation at the time of starting the robot based on the current effective value calculated by the current effective value calculation unit may be provided. Further, in the industrial robot according to claim 3 or 6, the break-in operation end determination means for determining the end of the break-in operation at the time of manufacturing the robot based on the current effective value calculated by the current effective value calculation means. It may be provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is an external view of an industrial robot according to one embodiment of the present invention. As shown in FIG. 2, an industrial robot according to an embodiment of the present invention is roughly classified into a manipulator 10 and a manipulator 1.
And controller 12 for controlling 0
And a teaching pendant 14 (operation terminal) for inputting an operator's instruction to the computer.

The manipulator 10 has a plurality of axes and has a function of an arm. Each of the plurality of axes is provided with a motor, and the operation of each axis is controlled by controlling the driving of the motor. The control of each motor is performed by a control unit 22 and a servo amplifier 28 provided in the controller 12. FIG. 1 is a block diagram showing a schematic electrical configuration of an industrial robot according to one embodiment of the present invention described above. Corresponding portions in FIG. 2 are denoted by the same reference numerals. In FIG. 1, reference numeral 20 denotes a manipulator 10
And 21 are motors provided on each axis of the motor 2.
0 is a position detector. When a plurality of shafts are provided, a plurality of motors 20 and position detectors 21 are also provided. The motor 20, the position detector 21, and the teaching pendant 14 are connected to the controller 12. The motor 20 is a brushless motor, and each armature is supplied with u-phase, v-phase, and w-phase three-phase currents.

The controller 12 comprises a control (CPU) unit 22, an external storage device 23, and a servo amplifier 28. The control unit 22 includes a CPU, ROM, RA
M and various interfaces (details of the contents and operations are omitted because this is a general computer system). The external storage device 23 limits various programs (teaching data) such as a line operation program, a break-in / warm-up operation program, various data used when executing the various programs, and a current flowing to the motor 20. Current limit value and the like are stored.

The control unit 22 reads various programs stored in the external storage device 23, and reads these various programs, various information such as current limit values, and the like, and the servo amplifier 2
The conditions for performing the break-in operation and the warm-up operation are calculated from various types of information (rotational position information of the motor, current value, etc.) obtained from 8 and the command value is output to the servo amplifier 28 based on the calculation result. . The servo amplifier 28, based on the calculation result output from the control unit 22,
The current is supplied to the motor 20 to drive the motor 20, and the value of the current actually flowing through the motor 20 is detected and output to the control unit 22. The value of the current to be outputted to the control unit 22 is a sampled value as a cycle of the sampling time T _s, which will be described later.

FIG. 3 is a block diagram showing a transfer characteristic example of a servo control system of one axis, wherein a loop R1 for performing current feedback control, a loop R2 for controlling speed feedback control, and a position feedback control. It has a loop R3 for performing. In the figure, K _p is a position loop gain, K _vp is the velocity loop gain, T _vi is the velocity loop integral time constant, G _i is a current loop gain, K _T is a motor torque constant, J _M is the motor inertia, J _L is the load Inertia is shown respectively.

In this servo control system, digital control is performed. That is, discrete control processing is performed at a preset fixed cycle (sampling time). This sampling time becomes shorter inside each of the loops. FIG.
In the current feedback control of the loop R1, the sampling (PWM) cycle is 1
When the frequency is 0 kHz, the speed is around 5 kHz in the speed feedback control of the loop R2, and is around 1 kHz in the position feedback control of the loop R2. Normally, in the position feedback control of the loop R3, a sampling frequency of about 100 Hz is sufficient (the sampling frequency mentioned here is merely a guide).

The above-mentioned sampling time T _s is a sampling time required for a process of calculating an effective current value, which will be described later. Since this effective current value is a value used when performing a warm-up operation, it is highly accurate. Is not required. Therefore, the sampling time T _s may be in accordance with any of the sampling times of the current feedback control of the loop R1, the speed feedback control of the loop R2, and the position feedback control of the loop R3.

Generally, there is no problem even if the current of the motor 20 instantaneously flows several times the rated current, and it can flow up to two to three times the rated current as needed. FIG.
FIG. 4 is a diagram showing an example of an overload curve of FIG. In this figure, the horizontal axis is the ratio between the current value of the motor 20 and the rated current value, and the vertical axis is the time during which the current can be continuously passed. In this figure, the curve labeled LC is the overload curve, and the area on the left side of the figure, that is, the shaded area is the normal operation, that is, the area where the operation can be performed without overload. is there.

As shown in this figure, when the motor 20 operates continuously for a long time, the ratio between the current value and the rated current value is 1.1 (indicated by IR1 in the figure) or more. In some cases it is overloaded. In addition, this is a case where a current twice as large as the rated current value (indicated by the symbol IR2 in the figure) is passed, and the current having this value is kept for 10.5 seconds (indicated by the symbol t1). Overflow causes overload. When obtaining the range of the overload curve, an effective current value is obtained from the measured current value, and the ratio of the effective current value to the rated current value is determined as a threshold (1.1).
It is performed by judging whether it is within. That is,
The effective value of the current is measured, and the operation state (condition) of the robot is determined according to the measurement result. If the operation state of the motor 20 is always on the overload curve LC, the running-in operation and the warm-up are performed with the highest efficiency. You can drive.

Next, a method for obtaining the current effective value will be described. First, the current values (current values of the u-phase, v-phase, and w-phase) flowing through each armature of the motor 20 are calculated by the servo amplifier 28, and the current value I flowing through the motor 20 is calculated. This calculation is performed based on the following equation (1).

[0019]

(Equation 1)

There are several methods for obtaining the current effective value I _RMS from the current value I calculated by the above equation (1). For example, the current effective value I _RMS is obtained by the following equation (2) using a moving average process.

[0021]

(Equation 2)

In the above equation (2), I _(i) is a current value, I ₍₀₎ is a current current value, I _(-1) is a current value detected at the previous sampling, and I _{(−) n)} indicates a current value detected at the time of sampling n times before. N is the average number of processes, indicates the number of samplings performed within the moving average time T _A , and is an integer of 1 or more. This average number of processes is calculated by the following equation (3).

[0023]

(Equation 3)

In the above expression, the operation expression "int ()" is an operation expression in which the value in parentheses is rounded down to the nearest whole number and converted to an integer. Note that an arithmetic expression for rounding or an arithmetic expression for round-up processing may be used as the arithmetic expression.

As another method for obtaining the effective current value I _RMS , there is a method using low-pass filter processing, which is obtained by the following equation.

[0026]

(Equation 4)

In the above equation (4), the coefficient A is a coefficient for determining the cutoff frequency of the low-pass filter, and 0 <A <1
Satisfying the following.

Next, changes in the output when the effective current value I _RMS is obtained by using the moving average processing and the low-pass filter processing will be described with reference to FIGS. 5 (a) and 5 (b). FIG.
FIG. 6A is a diagram illustrating a time change of a current effective value calculation result of the moving average process and the low-pass filter process when a step-shaped current C1 is supplied to the motor 20.

[0029] In the moving average processing described above, the response (current effective value) when a current flows C1 to changes stepwise at time t _0, the straight line C that varies linearly with a certain inclination
It is represented by 2. Moving average processing output (effective current value) C2
But when the time is the same as the step-like input (current) C1 and t _1, the moving average time T _A becomes T _A = t ₁ -t _0. By changing the moving average time T _A , the straight line C
2 changes. For example, if the moving average time is made longer (longer), the slope of the straight line C2 becomes gentler (in the direction indicated by the arrow in the figure).

Similarly, when the low-pass filter processing is used, as shown by a curve C3 in FIG. 5 (a), a response in which the rate of change gradually decreases is shown. The output of the low pass filter process (effective current value) and the time at which 63.2% of the step-like input (current) C1 and t _2,
The time constant τ of the low-pass filter is τ = t ₂ −t ₀ , and the cutoff frequency is 1 / τHz. The cutoff frequency can be changed by changing the coefficient A in the low-pass filter processing equation (4). For example, when the cutoff frequency is reduced, the output response becomes slow (in the direction indicated by arrow D in the figure).

Here, a method of setting the coefficient of the current effective value calculation formula will be described. First, in the example of FIG. 4, the overload determination threshold is set to 1.1 because the overload does not occur when the ratio between the current value and the rated current value is 1.1 (IR1) or less. Next, the coefficient of the calculation formula is as follows.
2) In the case of flowing, since the overload occurs after 10.5 seconds (t ₁ ), a coefficient having a characteristic as shown in FIG. 5B is set. However, with the coefficient set at 200%, FIG.
Does not coincide with the overload curve. However, since an approximate value is obtained, there is no practical problem. In order to increase the accuracy, it is sufficient to set a coefficient that can obtain a value very close to the overload curve over the entire region. That is, if the moving average time T _A or the cutoff frequency is set so as to obtain a response approximating the overload curve of the motor 20 for which the effective current value is to be obtained, efficient running-in operation and warm-up operation can be performed.

Next, the operation of the industrial robot according to one embodiment of the present invention during the break-in / warm-up operation will be described. [First Operation Example] FIG. 6 is a flowchart showing a first operation example at the time of running-in and warm-up operation of the industrial robot according to one embodiment of the present invention. Before starting the warm-up operation,
The operator uses the teaching pendant 14 to select execution of a program (teaching data) for running-in / warm-up operation from the programs stored in the external storage device 23. Next, the conditions for the break-in / warm-up operation are set.

One of the above-mentioned conditions is a regeneration speed initial value, and the regeneration speed at the start of the break-in / warm-up operation is given by a ratio (for example, 30%) when the normal speed is set to 100%. The other of the conditions is a threshold value of the maximum effective current value during the running-in / warm-up operation, and a limit value when the rated current value is 100% is given as a ratio (for example, 110%). Another condition is a maximum current effective value (judgment value) for end determination, which is given as a ratio to the rated current value (for example, 70%), like the threshold value.

When the above selections and settings are completed, a running-in / warm-up operation is started. First, in step SA1, a process of substituting the input initial value of the regeneration speed into the regeneration speed of the warm-up operation is performed. In step SA2, a process of clearing (substituting 0) the current effective value calculated so far is performed.

At step SA3, a process of clearing (substituting 0) the maximum effective current value during reproduction is performed. When the above initialization processing is completed, the processing proceeds to step SA4, in which the robot is operated at the speed specified by the reproduction speed according to the selected running-in / warm-up operation program,
A break-in / warm-up operation is performed. In step SA5, an effective current value is calculated based on the current value output from the servo amplifier 28.

At step SA6, the effective current value calculated at step SA5 is compared with the maximum effective current value. As a result of this comparison, if it is determined that the effective current value is larger, the process proceeds to step SA7, and the effective current value calculated in step SA5 is substituted for the maximum effective current value.

When the process at step SA7 is completed, and when the comparison result at step SA6 indicates that the effective current value is equal to or less than the maximum effective current value, the process proceeds to step SA7.
Proceed to 8. In step SA8, it is determined whether or not the running-in / warm-up operation program has been completed. If the result of this determination is "No", the process returns to step SA4, and the processes after step SA4 are performed again.

On the other hand, if the result of the determination at step SA8 is "Ye
s ", it is determined in step SA9 whether the reproduction speed is 100%. If it is determined that it is not 100%, the process proceeds to Step SA10. In step SA10, a process of calculating the next reproduction speed from the maximum current effective value at the time of executing one program and a preset threshold value of the maximum current effective value is performed. In this processing, the next reproduction speed is calculated by the following equation, for example. Reproduction speed = current reproduction speed + (threshold of maximum effective current value-
Maximum current effective value) Y

In the above equation, Y is a preset coefficient. This coefficient is determined by characteristics of the motor 20 and the like. In step SA11, the reproduction speed is compared with the initial value of the reproduction speed. If the reproduction speed is equal to or higher than the initial value of the reproduction speed, the process proceeds to step SA12. In step SA12, it is determined whether the reproduction speed is higher than 100%. If it is determined that the reproduction speed is higher than 100%, the process proceeds to step SA13. In step SA13, a process of substituting "100"% for the reproduction speed is performed. When this process is completed, and when it is determined in step SA12 that the reproduction speed is 100% or less, the process returns to step SA2.

On the other hand, if the reproduction speed is lower than the initial value in step SA11, the flow advances to step SA14. In step SA14, a process of substituting the initial value for the reproduction speed is performed. After the process in step SA14 ends, the process returns to step SA2.

On the other hand, if it is determined in step SA9 that the reproduction speed is 100%, the process proceeds to step SA15. In step SA15, the maximum current effective value is compared with the maximum current effective value (judgment value) for determining the end. As a result of this comparison, if the maximum current effective value is larger than the maximum current execution value (judgment value) for end determination, the process returns to step SA2. On the other hand, as a result of the comparison, when the maximum current effective value is equal to or less than the maximum current execution value (judgment value) for end determination, the processing (break-in / warm-up operation) ends.

Next, the relationship among the reproduction speed, the maximum effective current value, and the number of times of reproduction (time) when the industrial robot is controlled by the above processing will be described. FIG. 7 is a diagram showing the relationship between the reproduction speed, the maximum effective current value, and the number of times of reproduction (time) when the industrial robot is operated according to the first operation example. The description will be given in chronological order in FIG. First, the reproduction operation is started with the reproduction speed initial value given. In the period PA1 in the figure, since there is a margin in the maximum effective current value, the reproduction speed rapidly increases until it approaches the threshold value.

In the period PA2 in the figure, since the maximum current effective value reaches the threshold value, the change in the reproduction speed rise becomes gentle. During this period, the break-in / warm-up operation is progressing, and the regeneration speed is increased by the decrease in resistance (load). In the period PA3, the playback speed reaches 100%,
The reproduction speed no longer increases. However, break-in
Since the warm-up operation has progressed, the maximum current effective value decreases by the amount corresponding to the decrease in the resistance (load). In the period PA4, the maximum current effective value (judgment value) for ending determination of the break-in / warm-up operation is compared with the maximum current effective value, and the maximum current effective value is determined as the maximum current effective value (judgment value) for ending judgment. ), The break-in / warm-up operation is terminated when it becomes smaller (section PA).
3, end at the boundary of PA4).

Although the first operation example of the running-in / warm-up operation has been described above, it is troublesome to input the maximum current effective value (judgment value) for judging the end every time the warm-up operation is performed. Therefore, if the boundary between the warm-up operation and the normal operation (the maximum current execution value for determining the end of the warm-up operation) can be obtained for each industrial robot, the above-mentioned trouble can be saved. less than,
The operation in the case where the normal operation is performed and the maximum current effective value (judgment value) for determining the end of the warm-up operation will be described.

FIG. 8 is a flowchart showing the operation in the case where the normal regeneration operation (operation after the warm-up operation) is performed and the maximum current effective value (judgment value) for determining the end of the warm-up operation is obtained. The operator operates the teaching pendant 14 to read out the program for performing the warm-up operation from the external storage device 23 and instruct the control unit 22 to execute the program in the end determination capturing mode.

When the above operation is completed, the operation starts. First, in step SB1, a process of clearing (substituting 0) the current effective value calculated so far is performed. In step SB2, a process of clearing (substituting 0) the maximum current effective value during reproduction is performed.

When the above initialization processing is completed, the processing proceeds to step SB3, and the control unit 22 performs the normal operation according to the read-out program for the warm-up operation. In step SB4, an effective current value is calculated based on the current value output from the servo amplifier 28.

In step SB5, the current effective value calculated in step SB4 is compared with the maximum current effective value. As a result of this comparison, if it is determined that the current effective value is larger, the process proceeds to step SB6, and the current effective value calculated in step SB4 is substituted for the maximum current effective value.

When the process in step SB6 is completed, and when the comparison result in step SB5 indicates that the effective current value is equal to or less than the maximum effective current value, the process proceeds to step SB6.
Proceed to 7. In step SB7, it is determined whether or not the warm-up operation program has been completed. The result of this determination is “N
If "o", the process returns to step SB3, and the processes after step SB3 are performed again.

On the other hand, if the result of the determination in step SB7 is “Ye
In the case of "s", the process proceeds to step SB8, and a process of storing the maximum current execution value obtained by the above process is performed. At this time, the maximum current effective value for the end of the running-in / warm-up operation is determined to have a margin as indicated by α in FIG. 7 to the maximum current effective value (measured value) obtained in the above-described process. It is possible to prevent an erroneous determination of not being made. In this way, the maximum current execution value obtained when the normal operation is performed is stored as the maximum current effective value (judgment value) for judging the end of the warm-up operation. By performing the end determination of the warm-up operation based on the determination value, the trouble of inputting the determination value every time the warm-up operation is performed can be omitted. Further, it is possible to obtain an optimum maximum current execution value for end determination.

As described above, according to the first operation example of the industrial robot according to the embodiment of the present invention, the break-in
In the warm-up operation, the optimum regeneration speed is set using the maximum current effective value at the time of regeneration. (1) Regeneration can always be performed with the set maximum current effective value. (2) The running-in and warm-up operations can be completed in a short time. (3) The termination of the warm-up / warm-up operation can be determined quantitatively. (4) During break-in / warm-up operation, an abnormality such as overload is detected, and there is no need to stop halfway.

Further, a program (teaching data)
Since the end determination value can be measured and set for each time, (5) shortage of running-in and warm-up operation due to an incorrect setting of the end determination value can be prevented. (6) It is possible to prevent the running-in and warm-up operations from being performed for a long time due to a mistake in setting the end determination value. (7) Variation in the end determination by the program is eliminated. Further, in the present embodiment, since the effective current value can always be detected, it is possible to detect (8) an abnormality by comparing with the normal value.

As described above, the first operation example of the present invention has been described. In step S11 in FIG. 6, the reproduction speed is prevented from becoming lower than the initial value of the reproduction speed. However, the processing in step S11 is omitted. Even if the initial value of the reproduction speed is set to a slightly larger value, the operation speed may be automatically reduced to the optimum reproduction speed and the warm-up operation may be performed.

[Second Operation Example] FIG. 9 is a flowchart showing a second operation example of the industrial robot according to one embodiment of the present invention at the time of running-in and warm-up operation. Before starting the running-in / warm-up operation, the operator must use the teaching pendant 14.
The execution of the running-in / warm-up operation program (teaching data) is selected from among the programs stored in the external storage device 23.

Before the running-in / warm-up operation program is executed, an appropriate current effective value (end threshold value: for example, 60%) of the servo amplifier during the running-in / warm-up operation and the maximum current limit value I _{Max of the} amplifier are determined. Is stored as a constant.

When the operation starts, first, at step SC1
In, a process of clearing (substituting 0) the maximum current effective value I _RMSMax and the current effective value I _RMS calculated so far is performed. When the above initialization process is completed, the process proceeds to step SC2, and the control unit 22 performs the running-in and warm-up operation according to the selected running-in and warm-up operation program. In step SC3, an effective current value I _RMS is calculated based on the current value output from the servo amplifier.

In step SC4, a process of comparing the effective current value I _RMS with the maximum effective current value I _RMSMax is performed. If the current effective value I _RMS is greater than the maximum effective current value I _RMSMax, the process proceeds to step SC5. In step SC5, a process of substituting the effective current value I _RMS for the maximum effective current value I _RMSMax is performed. When the process in step SC5 is completed, and when the current effective value I _RMS is _{equal to} or _smaller than the maximum current effective value I _RMSMax in step SC4, the process proceeds to step SC6. In step SC6, it is determined whether or not the program has been completed. If the determination result is "No", the process returns to step SC2 to continue the execution (reproduction operation) of the program.

On the other hand, if the decision result in the step SC6 is "Yes", the process proceeds to a step SC7. In step SC7, a process of comparing the maximum effective current value I _RMSMax with the end threshold value is performed. That is, the maximum current effective value I
_It is determined whether _RMSMax has become smaller than the termination threshold,
If the maximum current effective value I _RMSMax is larger than the end threshold, the process proceeds to step _SC8 .

At step SC8, the maximum current effective value I
_RMSMaxThe current limit value is calculated from the current limit value I_LimAssigned to
The process returns to step SC1. This process
Then, the current limit value is calculated by the following equation, for example. I_Lim= AI_RMSMax+ B where A and B are maximum current effective values I_RMSMaxCurrent limit from
This is the coefficient for which the value is to be determined. On the other hand, in step SC7,
Is greater than the end threshold, the maximum current effective value I _RMSMaxof
If it is smaller, the running-in / warm-up operation ends.

Next, when the industrial robot is controlled by the processing of the second operation example, the maximum effective current value I _RMSMax ,
FIG. 10 shows the relationship between the current limit value I _Lim and the number of times of reproduction (time).
This will be described with reference to FIG. First, when the regeneration operation of the break-in / warm-up operation program is started, the sliding resistance of the speed reducer and the like and the viscous resistance of grease decrease as the number of regenerations increases, so that the effective current value gradually decreases. The regeneration operation is repeated, and an end threshold value in consideration of the margin (α) is set in advance to the maximum effective current value after the warm-up operation is sufficiently performed. The break-in / warm-up operation ends when the maximum current effective value becomes lower than the termination determination threshold during the break-in / warm-up operation.

As described above, according to the second operation example of the industrial robot according to the embodiment of the present invention, the break-in
In the warm-up operation, the current limit value is changed using the maximum current effective value at the time of regeneration. (1) Regeneration can always be performed with the set maximum current effective value. (2) The running-in and warm-up operations can be completed in a short time. (3) The termination of the warm-up / warm-up operation can be determined quantitatively. (4) During break-in / warm-up operation, an abnormality such as overload is detected, and there is no need to stop halfway. Further, in the present embodiment, since the effective current value can always be detected, (5) abnormality can be detected by comparing with the normal value. Furthermore, since the wave current limit value during the warm-up operation is set high so that there is no follow-up delay or the like, (6) the operation (operation) can be performed accurately without the warm-up operation.

[Third Operation Example] FIG. 11 shows a third operation of the industrial robot according to the first embodiment of the present invention during the break-in / warm-up operation.
9 is a flowchart illustrating an operation example. Before starting the running-in / warm-up operation, the operator uses the teaching pendant 14 to select the execution of the running-in / warm-up operation program (teaching data) from the program stored in the external storage device 23.

Before executing the running-in / warm-up operation program, the current limit maximum value for each axis, the current-limit setting value in the normal operation, the threshold value for the overload judgment, the judgment value for the running-in / warm-up operation end judgment , And the reproduction speed initial value are set as control constants.

When the operation starts, first, at step SD1, the maximum value is substituted for the current limit value I _Lim and the initial value is substituted for the reproduction speed. When the substitution process is completed, step SD2
Then, the current effective value I _RMS is cleared. The process further proceeds to step SD3 to clear the maximum current effective value I _RMSMax calculated so far.

When the above initialization process is completed, the process proceeds to step SD4, where the regeneration process is performed according to the selected running-in / warm-up operation program. In step SD5, an effective current value I _RMS is calculated based on the current value I _(i) output from the servo amplifier 28. In step SD6, a process of comparing the effective current value with the maximum effective current value is performed. If the current effective value is larger than the maximum current value, the process proceeds to step SD7, and the current effective value is substituted for the maximum current effective value.

When the process in step SD7 is completed, and when the effective current value is equal to or less than the maximum effective current value in step SD6, the process proceeds to step SD8. At step SD8, it is determined whether or not the program has been completed. If the determination result is "No", the process returns to step SD4 to continue the execution (reproduction operation) of the program. On the other hand, if the determination result in step SD8 is “Yes” (1
If (program end), the process proceeds to Step SD9.

At step SD9, it is determined whether or not the reproduction speed is 100%. If it is determined that the reproduction speed is not 100%, the process proceeds to Step SD10. In step SD10, the maximum current effective value at the time of executing one program and
A process of calculating the next reproduction speed from a preset threshold value of the overload determination of the maximum effective current value is performed. In this process, the next reproduction speed is calculated by the following equation, for example. Reproduction speed = current reproduction speed + Y * (threshold value-maximum current effective value)
In the above equation, Y is a preset coefficient, and this coefficient is set for each axis according to the characteristics of the motor 20 and the like.

When the processing in step SD10 ends, the flow advances to step SD11. In step SD11, the calculated reproduction speed is compared with the initial value of the reproduction speed. If the reproduction speed is equal to or higher than the initial value, the process proceeds to step SD12.
In step SD12, it is determined whether the reproduction speed is higher than 100%. If it is determined that the reproduction speed is higher than 100%, the process proceeds to step SD13. In step SD13, a process of substituting 100% for the reproduction speed is performed. When this process is completed, or when it is determined in step SD12 that the reproduction speed is 100% or less, the process returns to step SD2.

On the other hand, if it is determined in step SD11 that the reproduction speed is lower than the initial value, the process proceeds to step SD14. In step SD14, an initial value is substituted for the reproduction speed. After the processing in step SD14 ends, the processing returns to step SD2.

On the other hand, if it is determined in step SD9 that the reproduction speed is 100%, the process proceeds to step SD15. In step SD15, the maximum current effective value is compared with the current effective value (judgment value) for end determination. Here, when it is determined that the maximum current effective value is larger than the determination value, the process proceeds to Step SD16. In step SD16, the next current limit value is calculated from the maximum current effective value and substituted. In this process, the current limit value is calculated by the following equation, for example. Current limit value = A * maximum current effective value + B where A and B are coefficients for calculating the maximum current effective value.

When the processing in step SD16 ends, the processing proceeds to step SD17. In step SD17,
The calculated current limit value is compared with the current limit set value.
If it is determined that the current limit value is smaller than the current limit set value, the process proceeds to step SD18. Step S
In D18, the current limit setting value is substituted for the current limit value. When the process in step SD18 is completed, or when it is determined in step SD17 that the current limit value is equal to or larger than the current limit set value, the process returns to step SD2.
On the other hand, if it is determined in step SD15 that the maximum current effective value is smaller than or equal to the current effective value (judgment value) for end determination, the running-in / warm-up operation is ended.

In the third operation example, even if the break-in / warm-up operation is completed, the break-in / warm-up operation is not completely completed. For this reason, the operation accuracy cannot be compensated for in normal reproduction. Therefore, in this operation example, a function of changing the current limit value in the reproduction mode is required. Next, the operation in the reproduction mode in this operation example will be described with reference to FIG.

First, when the reproduction mode is entered, step SE1 is executed.
Clears (substitutes 0) the current effective value. Next, the process proceeds to step SE2, where the maximum current effective value is cleared (0 is substituted).
Is done. When the above initialization processing is completed, step SE
Proceed to 3 and operate the robot (reproduction process) according to the selected reproduction program. In step SE4, a current effective value is calculated based on the current value.

In step SE5, the current effective value calculated in step SE4 is compared with the maximum current effective value. As a result of this comparison, if it is determined that the current effective value is larger, the process proceeds to step SE6. In step SE6, the current effective value calculated in step SE4 is substituted for the maximum current effective value.

When the process in step SE6 is completed, and when it is determined in the comparison in step SE5 that the effective current value is equal to or less than the maximum effective current value, the process proceeds to step SE7. In step SE7, it is determined whether or not the program has been completed. If the determination result is "No", the process returns to step SE3, and the program execution (reproduction operation) is continued. On the other hand, if the result of the determination in step SE7 is "Yes" (one program ends), the flow proceeds to step SE8.

At step SE8, it is determined whether or not to end the reproduction mode. If the judgment result is "Yes", the reproduction mode is ended. On the other hand, if the result of the determination in step SE8 is "No", the flow proceeds to step SE9. In step SE9, the current limit value is compared with a current limit set value that is set in advance as a current limit value during normal operation (after the end of the warm-up operation). As a result of this comparison, if it is determined that the current limit value is larger than the current current limit set value, the process proceeds to step SE10.

In step SE10, a new current limit value is calculated from the effective current value by, for example, the following equation. Current limit value = A * Current effective value + B Here, A and B are coefficients set in advance to obtain a desired current limit value from the maximum current effective value.

When the processing in step SE10 ends, the processing proceeds to step SE11. In step SE11,
The current limit value calculated in step SE10 is compared with a preset current limit set value. As a result of this comparison, if it is determined that the current limit value is smaller than the current limit set value, the process proceeds to step SE12.

In step SE12, the current limit set value is substituted for the current limit value. This processing is performed in step SE10 because the warm-up operation has been sufficiently performed and the effective current value has decreased.
Is executed when the current limit value calculated in the step (2) becomes smaller than a preset current limit value. That is, it means the end of the original warm-up operation. When the process in step SE12 is completed, when it is determined in step SE9 that the current limit value is smaller than or equal to the current limit set value, and when it is determined in step SE11 that the current limit value is larger than or equal to the current limit set value. In this case, the process returns to step SE1.

Next, the current limit value, reproduction speed, maximum effective current value,
And the relationship between the number of reproductions (time). FIG. 13 shows the third
FIG. 9 is a diagram illustrating a relationship among a current limit value, a reproduction speed, a maximum current effective value, and the number of times of reproduction (time) when an industrial robot is operated according to an operation example. First, a regeneration speed initial value is given to the regeneration speed, and a current limit maximum value is given to the current limit value, and the regeneration operation (warm-up operation) is started. At first, the speed is high, so there is a margin in the maximum effective current value, and the reproduction speed rapidly increases until it approaches the threshold value.

As the reproduction speed increases, the maximum effective current value also increases. When the maximum effective current value increases to near the threshold value, the change in the increase in the reproduction speed becomes gentle. The regeneration speed increases as the warm-up operation progresses, and eventually the regeneration speed becomes 1
After reaching 00%, the reproduction speed no longer increases.
When the regenerating operation is further continued, the maximum current effective value decreases by an amount corresponding to the decrease in the resistance due to the warm-up operation.

When the reproduction speed reaches 100%, the current limit value changes from the maximum current limit value to the limit value calculated from the maximum effective current value. Thereby, the current limit value also decreases as the maximum current effective value decreases. Playback speed is 100
%, And when the maximum effective current value has decreased to a predetermined end determination value, that is, at the time point indicated by the symbol z1 in the drawing, the warm-up operation ends. Thereafter, the production operation can be performed in the regeneration mode.

At the start of the operation in the regeneration mode, since the warm-up operation has not yet been completed sufficiently, the operation is performed with the maximum effective current value being higher, and the operation is performed at the current limit value calculated from the maximum effective current value. Is done. As the regeneration operation (operation) continues, the resistance decreases and the maximum current effective value also decreases. Similarly, the current limit value decreases. When the current limit value decreases to a preset current limit set value, calculation from the maximum current effective value is stopped, and the current limit set value is set as the current limit value. At this stage, it means that the warm-up operation has been sufficiently completed, and the operation processing in the regeneration mode is not different from the normal operation.

Here, the difference in the warm-up operation time between the first embodiment and the third embodiment will be compared. The warm-up operation end determination of the first embodiment is given by a value obtained by adding a small margin to the maximum current effective value in normal operation, for example, the end determination value of Example 1 in the drawing, and the maximum current value is determined by this determination value. It is determined based on whether or not it has decreased (time z2 in the figure). On the other hand, in the third embodiment, as described above, the warm-up operation can be ended at the time point z1 in the drawing, so that the production can be started as quickly as the difference between the time points z1 and z2.

As described above, according to the third operation example of the industrial robot according to the embodiment of the present invention, the break-in
In the warm-up operation, the current limit value is changed using the maximum current effective value at the time of regeneration. (1) Regeneration can always be performed with the set maximum current effective value. (2) The break-in / warm-up operation can be completed in a shorter time than in the first and second operation examples. (3) The termination of the warm-up / warm-up operation can be determined quantitatively. (4) During break-in and warm-up operation, abnormalities such as overload are detected, and there is no stoppage. During the warm-up operation and at the beginning of the regeneration mode, the current limit value is set high so that there is no delay in following up. (5) Even if the warm-up operation is completed in a short time, the production operation can be performed accurately. (Operation). Further, in the present embodiment, since the effective current value can always be detected, by comparing with the normal value, (6) abnormality can be detected.

Although the third operation example of the present invention has been described above, the playback speed is not made lower than the initial value in step SD11 in FIG. 11, but the processing in steps SD11 and SD14 is omitted. Thus, the initial value of the reproduction speed may be slightly increased, or the reproduction speed may be automatically reduced to the optimum speed.

The industrial robot according to one embodiment of the present invention has been described above. However, the various calculation formulas used in this embodiment are merely examples, and other known calculation methods for obtaining the same effect can be used. good. Here, the speed and the limit value are calculated using the maximum current effective value in one program (teaching data), but the process of clearing the current effective value and the maximum current effective value at the beginning of the program is stopped, and The determination may be made based on the effective current value in the operation. Motor 20
Although a brushless motor has been described here, a similar effect can be obtained by using a DC motor or a stepping motor. However, the formula for calculating the current value differs depending on the structure of the motor.

In this embodiment, the servo amplifier 28
To measure the current actually flowing to the motor 20,
Although the method of calculating the effective current value from the measured value has been described, the same effect can be obtained even if the control unit 22 simply uses the current command value of the control data output to the servo amplifier 28. In order to simplify the description of the control system, a proportional (P)
Although control and proportional integral (PI) control have been described, other control systems (PID, modern control, etc.) may be used.

Although the calculated effective current value is used for determining the operating speed and for determining the end of the warm-up and warm-up operations, the effective current value during normal operation is stored, and the effective current value during normal operation is stored. The abnormality may be detected by comparing with a value. Also, by combining the first operation example and the second operation example,
A break-in / warm-up operation may be performed. In the second embodiment, the current limit value I _Lim is changed from I _MAX to the maximum current effective value I _{RMSM.
Although} it is made smaller in accordance with _ax , if the current limit value decreases beforehand before the break-in / warm-up operation ends, the current limit value may not be reduced further.

[0090]

According to the present invention, the break-in / warm-up operation can be completed efficiently in a short time, and the end of the break-in / warm-up operation can be determined quantitatively, and the break-in / warm-up operation is insufficient. There is no effect.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic electrical configuration of an industrial robot according to an embodiment of the present invention.

FIG. 2 is an external view of the industrial robot according to the embodiment.

FIG. 3 is a block diagram illustrating an example of a transfer characteristic of a servo control system of one axis.

FIG. 4 is a diagram showing an example of an overload curve of the motor 20.

FIG. 5 is a diagram for explaining a method of obtaining a current effective value I _RMS using a low-pass process.

FIG. 6 shows the break-in of the industrial robot according to the embodiment.
4 is a flowchart illustrating a first operation example during a warm-up operation.

FIG. 7 is a diagram illustrating a relationship among a reproduction speed, a maximum effective current value, and the number of times of reproduction (time) when the industrial robot is operated according to the first operation example.

FIG. 8 is a flowchart showing an operation when a normal operation is performed and a maximum current effective value (judgment value) for judging the end of the warm-up operation is obtained.

FIG. 9 shows the break-in of the industrial robot according to the embodiment.
It is a flow chart which shows the 2nd example of operation at the time of warming-up operation.

FIG. 10 is a diagram showing the relationship between the maximum effective current value and the number of times of reproduction (time) when an industrial robot is operated according to the second operation example.

FIG. 11 is a flowchart illustrating a third operation example during the break-in / warm-up operation of the industrial robot according to the first embodiment of the present invention.

FIG. 12 is a diagram for explaining an operation in a reproduction mode in this operation example.

FIG. 13 shows a current limit value, a reproduction speed, a maximum current effective value, and a current limit value when an industrial robot is operated according to a third operation example.
FIG. 7 is a diagram showing a relationship between the number of reproductions (time).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Manipulator 12 Controller (control means) 20 Motor 28 Servo amplifier (effective current value calculation means) 22 Control unit (effective current value calculation means, regeneration speed determination means, warm-up operation regeneration speed determination means, break-in operation regeneration speed determination means , Current limit value determination means)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02P 6/04 H02P 6/00 301

Claims (6)

[Claims] 1. An industrial robot having at least one axis, a manipulator driven by a motor, and a control device for controlling the motor, wherein the control device measures a current flowing through the motor. A current effective value calculating means for calculating a current effective value of the current; and a reproduction speed determining means for determining a reproduction speed as needed in accordance with the current effective value calculated by the current effective value calculating means. Features industrial robots. 2. The apparatus according to claim 1, further comprising: a warm-up operation regeneration speed determining unit that determines a warm-up operation regeneration speed at the time of starting the robot at any time based on the regeneration speed determined by the regeneration speed determining unit. The industrial robot as described. 3. The apparatus according to claim 1, further comprising a break-in operation playback speed determining unit that determines a break-in operation playback speed at the time of manufacturing the robot at any time at the playback speed determined by the playback speed determination unit. Industrial robot. 4. An industrial robot having at least one axis, the axis being driven by a motor, and a control device for controlling the motor, wherein the control device measures a current flowing through the motor. A current effective value calculating means for obtaining a current effective value of the current; anda current limit value determining means for determining a current limit value of the motor as needed based on the current effective value calculated by the current effective value calculating means. An industrial robot, comprising: 5. A warm-up operation current limit value determining means for arbitrarily determining a current limit value of the warm-up operation at the time of starting the robot based on the current limit value determined by the current limit value determining means. The industrial robot according to claim 4, wherein 6. A break-in operation current limit value determining means for determining a break-in current limit value of a break-in operation at the time of manufacturing a robot at any time based on the current limit value determined by the current limit value determining means. The industrial robot according to claim 4.