JPS59102595A - 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] [Field of Application of the Invention] The present invention relates to a robot safety device, and more particularly, when a worker approaches a robot for teaching,
This automatically limits the robot's maximum speed to ensure worker safety.

[Prior art]

When teaching data, etc. to a robot, in order to ensure the safety of workers, some robots are equipped with an interlock or the like to prevent the arm from moving at high speed. However, since this is set in software, it is powerless if the hardware such as the actuator that drives the arm goes out of control, and it cannot be said to be an essentially safe amount. Then, an ultrasonic switch or the like may detect this and cut off the power to the actuator. However, although such a device is effective when a third party accidentally approaches the device during normal operation, it is not useful when a third party approaches the device for the purpose of teaching or studying. The invention addresses the above-mentioned shortcomings of the prior art and aims to provide a robot safety device when an operator approaches a robot for instruction, taking into account possible equipment failures. It is said that

[Summary of the invention]

The robot safety device of the present invention includes a detection means that detects when a human approaches the robot, and when the detection means detects the approach of a human, switches the output voltage of the power supply device that drives the actuator to a low voltage, and also switches the output voltage of the power supply device that drives the actuator to a low voltage. The robot's operating speed can be kept low by means of switching the robot's program to a low-speed one! # value is 0 [Embodiments of the Invention] The present invention will be described in more detail below with reference to embodiments shown in the attached drawings.

FIG. 1 is an external view showing an example of a robot system equipped with the robot safety device of the present invention.

A safety mat 2 is placed around the industrial robot 1, and signals from the safety mat 2 are input to a control device 4 via a cable 3.

The structure of the safety mat 2 is generally such that a gap is provided between two electrodes, and when a person steps on the mat, the gap is collapsed and the electrodes come into contact, and the approach of a person is detected. There are many commercially available safety mats 2.

FIG. 2 is a circuit diagram showing an embodiment of the robot safety device of the present invention. The movement of the DC servo motor 5 is transmitted to an arm (not shown) by a reduction gear (not shown). The DC servo motor 5 is directly connected to a speed generator 6 and a rotary encoder 7, the speed generator 6 outputs a current speed signal NS, and the rotary encoder 7 outputs an encoded signal F8 indicating the current position.

This current speed signal N8 and a coded signal FS indicating the current position
As will be described later, the speed control signal O8 of each actuator calculated from the programmed trajectory of the arm is used as a feedback control signal to set the rotation of the DC servo motor 50 to the target speed. It is combined with the signal and input to the servo amplifier 8.

The servo amplifier 8 controls the power given from the power supply device 9 using a speed control signal O8 to drive the DC servo motor 5.
It is what drives the.

The power supply device 9 transforms the applied alternating current voltage V using a transformer 10, rectifies it to direct current using a rectifier 11, and then outputs the voltage.

Here, the transformer 10 has a primary winding ioa and a secondary winding 10.
Completed from b, 2nd volume ai.

b is provided with intermediate taps A and B. Rectifier 11
When the terminal 12 leading to the secondary voltage is connected to the intermediate tap A, a voltage is supplied to the rectifier 11, and when the terminal 12 is connected to the intermediate tap B, a low voltage is supplied to the rectifier 11.

FIG. 3 is a block diagram showing a control circuit for the actuator. Target value Pv is now! Nv and its deviation H
V is calculated. The current j[I'J■ is obtained by integrating the encoded signal FS output from the rotary encoder 7 and indicating the current speed using the counter 21. Deviation HV
is converted into target speed PS by an appropriate function subroutine 22. The portion indicated by number 23 in FIG. 3 is processed by software as a digital quantity. The target speed PS is converted into an analog value by a digital/analog converter (not shown), and then compared with the current speed signal NS output from the speed generator 6, and outputted as a speed control signal O8 representing the speed deviation. Speed control signal C
8 is after multiplying the gain by amplifier 24)
5 is input. Here, the amplifier 24 and the servo amplifier 25 correspond to the servo amplifier 8 in the second stage, as shown in the figure.

In the present invention, as shown in FIG.
and No.1-doware 42 to automatically reduce the arm speed during teaching. That is, the signal from the safety mat 2 is detected, the function subroutine 22 in FIG. 3 is switched to the low speed mode, and the power supply device 9 in FIG.
The intermediate tap of the transformer 10 inside is switched from A to B to suppress the maximum speed of the arm.

〔Effect of the invention〕 The effects of the present invention are as follows.

(b) Safety is increased because the arm speed is automatically suppressed during teaching.

(b) The motor will not start rotating at high speed even in the event of a runaway program or breakage of the control line, making it essentially safe.

Since the software must be changed to match the hardware, functions such as teaching and playback will not be affected.

) It can also be used as a means of ensuring safety during automated driving.

[Brief explanation of drawings]

FIG. 1 is an external view showing an example of a robot system equipped with the robot safety device of the present invention, FIGS. 2 and 3 are block diagrams showing an embodiment of the present invention, and FIG. 4 is a robot safety device of the present invention. FIG. 1 is a diagram schematically showing an apparatus. 1... Industrial robot 2... Safety mat 4... Control device 5... DC servo motor 6... Speed generator 7. ...Rotary encoder 8 ... Servo amplifier 9 ... Power supply 10 ... Transformer 11 ... Rectifier 21 ... Counter 22 ...Function subroutine 25 ...Amplifier 26 ...Power amplifier 41 ...Software 42 ...Hardware C8 ...・Speed control signal NS...Current speed signal FS...Encoded signal indicating current position...
...Target value W...Current value Claw L...Deviation PS...Target speed Agent Patent attorney Usui 1) Risai 3 Figure 23 Figure 4

Claims (1)

[Claims] a detection means for detecting when a human approaches the robot; and when the detecting means detects the approach of a human, the output voltage of the power supply device that drives the actuator is switched to a low voltage, and the program in the software is executed at low speed. A robot safety device characterized in that it is equipped with a means for switching the robot according to the operating speed, and is characterized in that the operating speed of the robot is kept low.