JPS58171290A - Safety device for 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 that prevents people or objects from entering the operating range of a robot arm and colliding with the arm.

Conventionally, in order to prevent accidents such as an arm colliding with a person while a robot is operating, a non-contact sensor is used to monitor the arm's operating area and detect when a person or object enters the operating area. A safety device for stopping at least an arm of a robot is known. However, in conventional safety devices of this type, non-contact sensors were installed on fixed parts such as the robot body and its surroundings, so a large number of sensors were required to monitor the entire arm's wide operating area. In addition, there is an influence between these sensors, and when the arm moves, the sensor detects the arm itself and malfunctions, or if there are people or objects around the operating area, it detects these and malfunctions. The drawback was that there was fear.

This invention uses a reflective ultrasonic sensor as a non-contact sensor whose detection distance can be automatically adjusted, and by installing it at the tip of a movable arm, the sensor detects a person who is in the arm's movement direction and within the arm's operating range. By detecting the → of an object using the ultrasonic sensor described above, the robot eliminates the above-mentioned conventional drawbacks, does not malfunction, and can instantly detect the intrusion of a person or object into the operation area with a small number of sensors. The purpose is to provide safety equipment for

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In Figure 1, 1 is the robot body, 2 is the robot body 1
8 is a first arm whose base is supported by the elevator 2 and rotates horizontally, and 4 is a second arm that is supported by the tip of the first arm 8 and rotates horizontally. A grip (not shown) that rotates around a vertical axis is attached to the tip of the second arm 4.

Further, in this embodiment, radar-type reflective ultrasonic sensors 5 are mounted on both sides of the tip of the second arm 4, respectively. In addition, in FIG. 1, 6 indicates the operating area of the arm.

The configuration of the ultrasonic sensor 5 is shown in FIG. 2. In Figure 2,
8 is an arithmetic unit having a CPU circuit, 9 is an intermittent oscillator, 10
is an amplifier, 11 is a transmitter, 12 is a receiver, 18 is an amplifier, 14 is a detector, 15 is an AND circuit, 16 is an output circuit,
17 is a distance adjuster, and 18 is a reference pulse 19 which is a distance adjustment signal.

In the reflection type ultrasonic sensor 5, the ultrasonic signal is oscillated by an intermittent oscillator 9, amplified by an amplifier 10, and output from a transmitter 11. The ultrasonic signal hits a person or object and returns as a reflected wave. This reflected wave enters the receiver 12, and the amplifier 18. The signals are guided to an AND circuit 16 via a detector 14, and the operation of the output circuit 16 based on these outputs causes the robot to stop operating if a person or object enters the operating range of the arm.

In this case, the timing of transmitting and receiving signals is shown in FIG. 8, in which an ultrasonic signal emitted from the transmitter 11 hits a person or the like and a reflected wave returns to the receiver 12.

In FIG. 8, the time shift of the reflected waves indicates the distance from the transmitter 11 to a person or object. Therefore, in order to select a necessary received signal, the reference pulse 18 and the distance adjustment signal 19 from the arithmetic unit 8 are input to the distance adjuster 17 having a trigger circuit, etc., and the reception gate pulse is sent to the AND circuit 15.
, so that only the necessary parts can be detected. Further, the reception gate pulse is determined as follows.

When determining the distance at which you want to detect a person, etc., if you know the propagation speed of the ultrasonic wave, you can find out the time Δt for the ultrasonic wave emitted from the transmitter to travel the round trip distance of 2L and return. If a signal equal to or higher than the threshold level, which is before or after the above-mentioned time Δt, is returned after sending the ultrasonic wave, it can be determined that there is a person within a certain distance. The ultrasonic sensor of this embodiment is attached to the tip of the arm, so if the detection distance is kept constant, there may be a person or object quite far outside the operating area 6 depending on the position of the arm. is also detected. Therefore, the detection distance by the ultrasonic sensor is limited depending on the current position of the arm and the direction in which it moves. For this purpose, the necessary detection distance is determined by the calculator 8 according to the position and operating direction of the ultrasonic sensor, and the distance adjustment signal 19 is sent from the CUP circuit to the distance adjuster 17 to determine the timing of the reception gate pulse. The time τ from wave transmission is automatically adjusted continuously, and the detection distance is variable depending on the arm position.

In the above embodiment, it is preferable that the ultrasonic sensor is provided not only at the tip of the second arm but also on both sides of the tip of the first arm. Alternatively, only the ultrasonic sensor on the operating direction side may be operated. Further, in the above embodiment, the first. Although a robot with a second arm has been described, the invention can also be applied to a robot with one arm.

As explained above, the present invention provides a reflective ultrasonic sensor at the tip of a movable arm, automatically adjusts the detection distance of the ultrasonic sensor according to the position of the arm, and automatically adjusts the detection distance of the ultrasonic sensor depending on the position of the arm. Since only people and objects within the operation area are detected, the robot can detect people and objects within the operation area and stop the arm without causing malfunctions using a small number of sensors. This has the effect of reliably preventing collisions with people or objects that enter the robot's operating area, and improving the operating rate of the robot by eliminating malfunctions.

[Brief Description of the Drawings] Fig. 1 is a plan view of a robot equipped with a safety device according to an embodiment of the present invention, and Fig. 2 is a block diagram showing an ultrasonic sensor of the safety device according to an embodiment of the present invention. Figure 8 is the second
It is a figure which shows the signal timing at the time of the detection by the ultrasonic sensor of a figure. 8.4...Arm, 5...Fist ultrasonic sensor,
6...Arm movement range. Agent Makoto Kuzuno - Child 1 figure procedural amendment (spontaneous) 58 1 1g Showa year month day 1, case indication patent application No. 57-53332 2, title of invention Robot Y safety device 3, person making the amendment Relationship to the incident Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Mitsubishi Electric Corporation Representative Hitoshi Katayama Department 4, Representative Address 2-2 Marunouchi, Chiyoda-ku, Tokyo No. 3 No. 5, Subject of correction (1) Detailed description of the invention column 6 of the specification, Contents of correction (1) Page 2 of the specification, lines 9 to 10, line 1, "Detection distance as a non-contact sensor" The phrase "Using a reflective ultrasonic sensor that can be automatically adjusted" should be corrected to read "Using a reflective ultrasonic sensor as a non-contact sensor, the detection distance can be automatically adjusted." (2) On the 16th line of page 3, it says [18 is one reference pulse is a distance]. Correct it to "18 is a reference pulse and 19 is a distance." (3) From line 20 on page 3 to line 1 on page 4, the ultrasonic signal emitted from 111 hits a person or object and the reflected wave returns. '' should be corrected to ``An ultrasonic signal is emitted from 11, and the signal hits a person or object and receives a reflected wave that returns.'' (4) On page 4, lines 2 and 3, “AND circuit 16
" has been corrected to read "AND circuit 15." (5) In the first line of page 5, the statement ``signals above a certain threshold level before and after At'' is corrected to 1 for significant signals above a certain threshold level before and after L. (6) On page 5, line 11 of the same page, replace "CUP circuit" with J
"CPU circuit". 3-524-

Claims (1)

[Claims] A reflective ultrasonic sensor with an automatically adjustable detection distance is installed at the tip of the movable arm of the robot, and the ultrasonic sensor detects only people and objects within the movement area of the arm in the direction of movement of the arm. A robot safety device characterized by: