JPS58223597A - Safetyapparatus of industrial robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a safety device for industrial robots.

Generally, industrial robots are dangerous during work, so safety is maintained by building safety facilities such as surrounding the operating range with fences, etc. However, when teaching the robot or adjusting its operation, the worker must At this time, the robot may suddenly change its behavior depending on the contents of the program, or
If the robot moves significantly or behaves in an unexpected manner, there is a risk of an accident in which the worker and the robot come into contact or collide.

It is an object of the present invention to provide a safety device that prevents this type of accident.

When a motor drives the drive shaft of a robot at a predetermined speed from a stop for a predetermined time and then stops, a large starting current normally flows through the motor for acceleration at startup, as shown in the first diagram, and then a predetermined speed. When the speed reaches a certain level, a constant current flows, and when the vehicle decelerates, the drive shaft releases its stored energy, causing a deceleration lightning in the opposite direction to sell. However, if a human and robot come into contact or collide, the load on the motor will increase, so if this contact occurs during startup,
The starting current increases by degrees from the starting tm value shown in the first diagram, and when it occurs during operation at a constant speed, it increases from the steady current value shown in the first diagram.

The above relationship also holds true for the motor that is being taught to the robot.

Therefore, the present invention provides a means for detecting when the motor electromagnetic current and eIH normal starting current and steady current as shown in the first diagram are compared during driving and steady operating periods, and when the motor current increases from these. is provided, and the motor is stopped by this output.

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

FIG. 2 shows a block diagram of a first example of implementing the invention.

(1) is the robot drive motor (hereinafter referred to as the motor)
For example, a DC servo motor is used, and control transistors (2A) (2B) (20) (2D), m
It is connected to a power supply terminal (5) via an L detector (3) and an electromagnetic switch (4).

(6) is a comparator that compares the voltage corresponding to the motor current input through the current detector (3), amplifier (force and filter (8)) with the reference voltage corresponding to the normal maximum starting current value. , which generates an output when the motor current exceeds this reference value.

(9) is an AND gate, which is connected to the output side of the comparator (6), and is a gate obtained from the driving electromagnetic signal which is synchronized with the circulation period of the driving light of the motor (1) as shown in the first diagram. It is opened by signal G. αQ is a comparator,
It compares the voltage corresponding to the motor current with a reference voltage corresponding to a normal steady-state current value, and outputs when the voltage corresponding to the motor current exceeds this reference voltage. αB is an AND gate, which is connected to the output side of the comparator OQ,
As shown in the first diagram, it is opened by a gate signal G synchronized with the period of steady current flowing through the motor (1). This gate signal G2 is generated, for example, according to a preset acceleration time limit. (It may be generated from the motor wL flow via a differentiator, an inverter, etc.).

) The electromagnetic switch (4) is connected to the AND gate (9) αD
It is opened when an output is supplied from □ via OR gate α2 and amplifier α□□□.

Thus, if a worker or a robot comes into contact with the motor (1) when starting it, the load increases and the starting current increases compared to the normal time as shown by the broken line a in Figure 1, so the comparator (
An output signal is generated from 6) which passes through the opened AND gate (9) and energizes the electromagnetic switch (4) to open it. 1
If the normal acceleration time limit is exceeded, as shown by the broken line in the figure, the electromagnetic switch (4) is energized through the comparator (the output signal of the output signal Ql) to open it. to stop the motor (1). In addition, when a worker touches the robot during steady operation (1), the steady-state lightning increases from the normal value as shown by the broken line 0 in Figure 1 due to the increased load, so an output signal is generated from the comparator section. This output signal passes through the opened AND gate αυ and energizes the electromagnetic switch (4) to open it and stop the motor (1). This comparator α1 also generates an output signal at the time of starting, but since the AND gate αυ is closed at this time, the electromagnetic switch (4) is not energized by this output signal.

As described above, according to the present invention, there is provided a means for comparing the motor current with the normal maximum starting current during the driving current flow period of the motor and detecting that the motor current exceeds the normal maximum starting current, such as a comparator (6). ) and an AND gate (9), and a means for comparing the motor current and a normal steady current during the steady current flow period of the motor and detecting that the motor current exceeds the normal steady current, e.g. Comparator a1
and an AND gate αυ, and the motor is stopped by the outputs of these two means.
In the event of contact or collision between a human and the robot during startup or steady operation, the motor can be stopped quickly, resulting in safety for the worker.

[Brief explanation of drawings]

Figure 1 shows the motor current during normal operation, gate signals G, and G.
FIG. 2 shows a block diagram of an example of implementation of the present invention. (6) Q(1... comparator (9) αυ...
ANDGATE patent applicant Honda Motor Co., Ltd.

Claims (1)

[Claims] During the drive current flow period of the robot drive motor, the motor current and normal maximum starting 1! means for comparing the motor current with the normal steady-state current and detecting that the motor current exceeds the normal maximum starting current; A safety MI for an industrial robot, characterized in that: means for detecting that a normal steady state current has been exceeded, and the robot drive motor is stopped by the output of the two means.
N.