JPH0422946Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an abnormality detection device for industrial robots, and is useful for improving the safety of industrial robots.

Conventional technology The conventional deviation abnormality detection device for industrial robots is
Tolerance values are set independently for each axis of an industrial robot, and the difference, or deviation, between the command value to the actuator of a certain axis and the current value from the position detector of that axis is less than or equal to the set tolerance value. If the tolerance value is exceeded, the industrial robot automatically stops operating as a deviation abnormality or displays a failure message to notify the operator of the abnormality.

In other words, if the industrial robot deviates significantly from the target trajectory, the deviation will increase, and this is used as a measure for abnormality detection.

Problems with the conventional technology Teach-and-play industrial robots move at high speed during playback, but at low speed when teaching, and are generally equipped with a high-speed/low-speed switch for this purpose. It is true.

In other words, if the high/low speed selector switch is on the high speed side, the taught working speed (usually high speed)
The industrial robot operates at a safe speed (usually lower than the taught working speed) if it is on the low side.
controlled to operate.

By the way, the tolerance values of conventional industrial robot deviation abnormality detection devices are mainly aimed at detecting abnormalities during regeneration of industrial robots, so they do not exceed the level of relatively large deviations that may occur during high-speed operation. Both are set to relatively large values.

However, during low-speed operation during teaching or when stationary,
Since the deviation reaches the high-speed level only when the abnormality has progressed considerably, conventional devices that always use the tolerance value have a problem in that the timing of abnormality detection is delayed.

In particular, since people are working near the industrial robot during teaching, it is very dangerous to be unable to detect an abnormality unless the deviation becomes large.

However, if the allowable value is made small, the abnormality detection signal will be output more often than necessary during high-speed playback, resulting in the neglect of abnormality detection during low-speed operation, as described above.

Purpose of the invention The purpose of the present invention is to provide an abnormality detection device for an industrial robot that can effectively detect abnormalities not only during playback of the industrial robot but also during teaching.

Structure of the invention The abnormality detection device for an industrial robot of the present invention is relatively unique among abnormality detection devices for an industrial robot that outputs an abnormality detection signal when the speed, acceleration, deviation, etc. of the industrial robot exceeds a predetermined tolerance value. Storage means for storing at least a first stored value having a large value and a second stored value having a relatively small value, and the first stored value is selected as the permissible value during playback, and the second stored value is selected during teaching. The present invention is characterized in that it includes a tolerance value selection means for selecting the tolerance value as the tolerance value.

Function The abnormality detection device for industrial robots of the present invention has the following functions:
Rather than having only one allowable value for determining abnormality, it has at least two values, a relatively large value and a relatively small value.

Then, a relatively large value is selected as an allowable value during high-speed operation during reproduction, and a relatively small value is selected during low-speed operation during teaching or when stationary, and an abnormality determination is performed.

This prevents the abnormality detection signal from being outputted unnecessarily frequently during high-speed operation, and improves safety because the abnormality detection signal is immediately output when a small deviation occurs during low-speed operation or at rest.

Embodiments Hereinafter, the present invention will be explained in more detail based on embodiments shown in the figures. Fig. 1 is an overall configuration diagram of an industrial robot including a deviation abnormality detection device according to an embodiment of the present invention, Fig. 2 is an external view of main parts of the operation buttons of the industrial robot shown in Fig. 1, and Fig. 3 a , b, and c are flowcharts showing the main parts of the operation of the deviation abnormality detection device according to an embodiment of the present invention. Note that the present invention is not limited to the embodiments shown in the figures.

The industrial robot shown in FIG. 1 includes an articulated robot 1, a control device 2 with a built-in computer,
Remote controller 3 for teaching at hand
It is basically equipped with the following.

As shown in Figure 2, the remote controller 3
is provided with a start button 4, a pause button 5, a stepback button 6, a high speed/low speed changeover switch 7, etc.

The above-mentioned components 1 to 7 are the same as conventionally known components.

However, the control device 2 is different from the conventional one in that it functions as a deviation abnormality detection device according to the present invention.

Therefore, with reference to FIG. 3, the function of the deviation abnormality detection device will be explained in accordance with the order of operation.

First, as shown in FIG. 3a, the control device 2 sets a flag for switching whether the articulated robot 1 is operated at high speed or at low speed. That is, the high speed/low speed changeover switch 7 is sensed to determine whether high speed or low speed is selected (S1).

If low speed is selected, a flag is set to low speed (S2).

If high speed is selected, it is determined whether the start button 4 is turned on (S3).

If the start button 4 is not pressed, the articulated robot 1 is not moving yet and is in a stationary state, so the flag is set to low speed instead of high speed (S2).

If the start button 4 is turned on, the flag is set quickly (S4) since the actual playback operation is to be performed.

As shown in FIG. 3b, when calculating the command value to the articulated robot 1, first, the interpolation number N is calculated from the two taught points and the taught specified speed (S11).

Next, it is determined whether the flag is set to low speed (S12).

If the flag is not low speed, then the speed is high, so interpolation point calculation is performed using the interpolation number N (S15). These interpolation points become command values for the articulated robot 1.

If the flag is set to low speed, the above interpolation number N is greater than the predetermined low speed interpolation number N.
It is determined whether or not is smaller (S13).

If N<N, the specified speed is lower than the predetermined low speed, so the specified speed is adopted and interpolation point calculation is performed using the interpolation number N (S15).

If N<N, a low speed which is a safe speed lower than the specified speed is adopted, the interpolation number N is replaced with the low speed interpolation number N (S14), and interpolation point calculation is performed (S15). That is, interpolation point calculation is performed using the low speed interpolation number N.

As shown in Fig. 3c, when processing deviation abnormality detection, each time a command value is output to the articulated robot 1, the current value of the articulated robot 1 is read (S21), and the current value is calculated from the command value. The deviation is calculated by subtracting (S22).

Next, it is determined whether or not the flag is set to low speed (S23), and if it is not set to low speed, the first stored value _L1 , which is a relatively large value, is set as the allowable value L (S24). . If the flag is set to slow, the second stored value L ₂ is relatively small.
is set as the allowable value L (S25).

Next, it is determined whether the deviation is smaller than the tolerance value L (S26), and if the deviation is smaller than the tolerance value L, it is determined to be normal, but if the deviation is smaller than the tolerance value L, it is determined that the deviation is abnormal, The process moves to deviation abnormality detection processing such as outputting an abnormality detection signal.

In other words, when the articulated robot 1 is actually operated at high speed, a relatively large allowable value is used as the standard for determining deviation abnormality, but when the articulated robot 1 is stationary or operating at low speed In some cases, a relatively small allowable value is used as a criterion for determining deviation abnormality.

Therefore, it is possible to prevent the deviation abnormality detection state from occurring unnecessarily frequently during high-speed operation, and
When the system is stationary or operating at low speeds, even small deviations can be detected as abnormal deviations, improving safety.

As another example, when a multi-stage speed switching switch with three or more stages is provided instead of a two-stage speed switching switch of high speed/low speed, a flag is provided for each stage, and a memory with a different size is stored for each stage. For example, a value is set and a stored value corresponding to the set flag is selected as an allowable value.

Another example is one in which the actual operating speed of the industrial robot is calculated from a change in the current value, and an allowable value is calculated and set according to the actual speed (for example, using a linear function).

Although the abnormality detection device of the present invention has been described above using deviation abnormality detection as an example, it will be easily understood that the present invention can also be applied to speed abnormality detection and acceleration abnormality detection.

Effects of the invention According to the invention, in an abnormality detection device for an industrial robot that outputs an abnormality detection signal when speed, acceleration, deviation, etc. exceed a predetermined allowable value, the first memory value is a relatively large value. a storage means for storing at least a second stored value that is a relatively small value; and a tolerance value that selects the first stored value as the tolerance value when the speed is high and selects the second stored value as the tolerance value when teaching. An abnormality detection device for an industrial robot is provided, which is characterized by being equipped with a selection means, whereby abnormality detection is performed based on an appropriate tolerance value corresponding to the operating speed of the industrial robot, so that high-speed reproduction is possible. Safety is always ensured during operation, low-speed operation during teaching, and when stationary.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of an industrial robot including a deviation abnormality detection device according to an embodiment of the present invention, Fig. 2 is an external view of main parts of the operation buttons of the industrial robot shown in Fig. 1, and Fig. 3 a , b, and c are flowcharts showing the main parts of the operation of the deviation abnormality detection device according to an embodiment of the present invention. Explanation of symbols, 1...Articulated robot, 2...
Control device, 3...Remote controller, 4...
Start switch, 7...High speed/low speed changeover switch.

Claims (1)

[Scope of Claim for Utility Model Registration] An abnormality detection device for an industrial robot that outputs an abnormality detection signal when the speed, acceleration, deviation, etc. of the industrial robot exceeds a predetermined tolerance value, Storage means for storing at least a memorized value and a second memorized value having a comparatively small value; the first memorized value is selected as the permissible value during playback, and the second memorized value is selected as the permissible value during teaching. An abnormality detection device for an industrial robot, characterized in that it is equipped with a tolerance value selection means.