JPS5969297A - Safety device for 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.

In particular, it has been made possible to increase safety even in the event of failure of the robot/soto control device itself. Regarding safety equipment for industrial robot throats.

Conventional robot control devices employ a processing method in which the same computer controls the movements of the robo-nod while monitoring abnormalities in its movements. has the disadvantage that it is impossible to reliably detect the abnormality.

FIG. 1 shows a conventional multi-degree-of-freedom, articulated industrial robot. This is an example of a control configuration for abnormality detection and drive source disconnection. In the same figure, sensors S1 to Sn detect, for example, a robot.
Exceeding the operating range of the motor, motor speed, or patent application of 1972
Detection of human entry as described in the specification of No. 31163 is carried out, and a corresponding signal is sent to the control computer 12 via the interface 11. The control computer 12 detects an abnormality from these signals, and if an abnormality is detected, it outputs a stop signal 18 to the A converter 16 and sample hold circuit 14.

An output cutoff signal 17 is output to the main circuit of the servo amplifier 15 and the motor power supply 16 to cut off the drive source.

The robot was stopped.

However, according to such a conventional configuration, when a control device such as the control computer 12, alpha converter 13, sample and hold circuit 14, etc. breaks down as described above, even if abnormal control is performed due to the fault, it will not occur. Due to this failure, even if the sensors S1 to Sn detect an abnormality, the stop signal 17 or the stop signal 19 for the S'-bomber 15 cannot be properly captured, causing a serious accident. There is a fear. In particular, in recent years, robots have been required to perform high-speed and complex movements, and as a result, when the number of circuit components of the control device itself increases due to an increase in the number of axes of the robot, etc., this risk becomes even greater. And the conventional Ropo...I
In the case of control, when such a situation occurs, Rojo...
The robot operator used to press the emergency stop button to stop the robot in case of an abnormality, but as robots became faster and more complex, the above method could no longer be used to deal with the problem. There was a problem that

The purpose of the present invention is to eliminate the drawbacks of the conventional devices described above, and to be able to accurately detect abnormal operation even if a failure occurs in the control device that controls the operation of the robot. To provide safety equipment for industrial robots, such as stopping them.

The device of the present invention has a function of detecting an abnormality from signals from various sensors independently of the robot control device, and also has a function of detecting an abnormality of the robot control device itself. This feature is characterized in that the operation is stopped.

An embodiment of the present invention will be described below with reference to FIG. The robot control configuration shown in the figure shows an abnormality detection and accompanying stop processing method, and corresponds to the conventional configuration shown in FIG.

The same symbols as in FIG. 1 indicate the same contents. In FIG. 2, the control computer 12. The abnormality detection and drive source disconnection operations when the D/A converter 15° sample and hold circuit 14 is operating normally are the same as in the case of FIG. A determination circuit 20, which is an abnormality detection circuit, is provided. The operations of the control circuit 21 and level detection circuit 22 will be explained.

Various detection signals detected by sensors S1 to Sn are as follows.

The signal is sent to an independent abnormality determination circuit 20 outside the management range of the control computer 12. The determination circuit 20 performs abnormality determination and abnormality processing when an abnormality occurs according to a predetermined procedure on the detection signals of the sensors S1 to Sn, and outputs the results, and further converts each abnormality detection signal into one output 27. control circuit 2
Output to 1 (if there is even one error, an error is output).

Next, the control computer 12. If either the D/Af converter 13 or the sample hold circuit 14 breaks down,
Using the fact that the command voltage 19 to the servo amplifier 15 shows an abnormal value, the level detection circuit 22 detects the abnormal value and outputs a signal 28 to the control circuit 21 .

Furthermore, the test code 25 is periodically sent from the control computer 12.
is generated and checked by the determination circuit 20, and if there is an abnormality, an abnormality signal 27 is also output to the control circuit 21. When the control circuit 21 receives the signal 27 from the 1 determination circuit 20 or the signal 2 from the level detection circuit 22,
A disconnection signal 29 is output to the main circuit of the servo amplifier 15 and the motor power supply 16 via the OR circuit 24 to prevent the rotor/throat from running out of control, and an emergency stop operation command 26 is output to the control computer 12, and the operation A warning is issued to the person through the lamp 23 or the like.

Among the above operations, the level detection circuit 22 detects an abnormality in the control device portion. An example of the abnormal value detection method will be described with reference to FIG. During normal operation, the control computer 12 outputs a command voltage V to the servo amplifier 15 by setting the νA converter 13 and sample hold circuit 14 to J+ at fixed time intervals (hereinafter referred to as sample times) Tg. In the level detection circuit 22, this sample time Tz
The needle side calculates the change Δυ in the command voltage V at each sufficiently short time interval t= compared to , and outputs an abnormal value detection signal 2 days when this ΔV exceeds a predetermined set value. This method can be similarly applied regardless of whether the command voltage V is positive or negative, increases or decreases.

In the embodiment shown in FIG. 2, the 1 determination circuit 20. Control circuit 2
1. Although the circuit and level detection circuit 22 are separate circuits, it is clear that they may be replaced with one processor that performs some or all of these processes.

As is clear from the above explanation, according to the present invention, it is possible to reliably deal with abnormalities in the robot/nod control unit itself, and to avoid collisions with hot humans and collisions of the robot itself with other devices or the robot itself. Runaway accidents like this can be more reliably prevented.

It has the effect of greatly improving the safety of the robot, and it also prevents abnormal situations from occurring when operating the robot without using a control computer, such as when evaluating only the robot body. This also has the effect of being able to safely stop the Ropo Nodo even in the event of an accident.

[Brief explanation of drawings]

Figure 1 is a control configuration diagram of a conventional industrial robot/soto. FIG. 2 is a block diagram showing an embodiment of the present invention. FIG. 3 is an explanatory diagram of the operation of the level detection circuit shown in FIG. 2. 12... Control computer, 13... Le θ converter, 14
... Sample hold circuit, 15... Servo amplifier, 16... Motor power supply, 20... Abnormality determination circuit, 2
1... Control circuit. 22...Level detection circuit, S1-Sn...Sensor. 1-P 砒五□d力古↓ 蓬 1) Fangto', i-o 1 Mouth Sai 3 Mouth One

Claims (1)

[Claims] a first abnormality detection means for detecting an operational abnormality by monitoring the output of a sensor that detects the operational state of the industrial robot;
a second abnormality detection means for detecting an abnormality in the operation of a control device for controlling the industrial robot; and a second abnormality detection means for driving the industrial robot when an abnormality is detected by the first and second abnormality detection means. A safety device for an industrial robot, characterized in that it is equipped with a stopping means for stopping the robot.