JPH01301093A - Robot safety device - Google Patents

Abstract

PURPOSE:To make an abnormal judgment performable in a short time during robot operation by installing an abnormal judgment means for collating information discriminated by a sorting means with an abnormal criterion, feeding a motor driver and a controller with the abnormal judgment signal each and interrupting any motion of the robot. CONSTITUTION:Judging information out of a judging information generating means 3 is collated to a sort reference given by a sort reference designating means 7 and features are sorted by a judging information sorting means 4. Information discriminated by this sorting means 4 is collated by an abnormal judging reference being given by an abnormal judging reference designating means 8 and an abnormal judging means, and an abnormal judging signal 9 is fed to a driver for a robot arm driving motor and a controller for converting a program into an operating command, then any motion of a robot is interrupted at once.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention detects abnormalities at an early stage when they occur in industrial robots, numerical control (hereinafter abbreviated as NC) applied machines, etc., and prevents damage to the human body and the robot and its surroundings. This relates to a robot safety device that prevents damage to equipment.

Conventional technology In conventional industrial robots, NC applied machines, etc., when an abnormal overload is applied during operation, the current flowing through the motor increases, so this is detected by a thermal protector and an abnormality occurs. It detects what has happened. Another method is to reduce the number of drive command pulses to be given to the motor drive device and the amount of feedback pulses from the encoder, since the feedback signal will stop when the signal line from the encoder is disconnected during operation or the encoder malfunctions. Since the difference between the two encoders continues to increase, an upper limit threshold value is set there to detect an abnormality in the second encoder. (See Figure 4) Problems to be Solved by the Invention However, in the method described above, if an abnormality occurs while the robot is moving before or after the positioning point, the motor will slow up or stop operating or stop. Since the motor is in the process of slowing down, there is a problem in that an overcurrent sufficient to activate the thermal protector does not flow through the motor, making it impossible to detect an abnormality. Also, in the latter method, depending on the upper threshold setting,
There is a problem in that the robot may incorrectly detect an abnormality depending on the degree of load such as temperature or load, and the detection response may be delayed, causing the robot to run out of control over a large distance until it is stopped.

Means for Solving the Problems In order to solve the above-mentioned problems, the robot safety device of the present invention detects abnormalities in the operation command signal from the control device and the feedback from the position detector connected to the motor in the positioning device. determination information generation means for determining the
Judgment information classification means that classifies the characteristics of the judgment information by comparing it with the classification standard given by the classification standard specifying means; It is equipped with an abnormality determining means for determining whether to send out a determination signal.

Effect: With the above-described configuration, the present invention extracts feature points from the relationship between the motion command signal and the feedback signal from the position detector during robot motion, and performs abnormality analysis by comparing them with preset criteria. Because it is sequential, the effects of the aforementioned operating conditions and external disturbances such as load and temperature are small, and abnormalities can be determined in an extremely short time compared to conventional methods that cannot or are delayed in determining abnormalities. It is possible.

Embodiment Hereinafter, a positioning device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the signal processing procedure of the positioning device of the present invention. Further, FIG. 2 shows the overall configuration including this device. The operation command signal 1 and the feedback signal 2 in FIG. 1 are signals sent from the control device 12 and the position detector 15 in FIG. 2, respectively. FIG. 3 is a flowchart showing a first embodiment of the present invention. First, when the criterion 16 is input, a timer for monitoring the state is initialized, and at the same time, the start of the timer is set. Next, the operation command signal Pd and feedback signal PI are inputted from each of the peripheral devices, and the deviation pulse ε is calculated. If the absolute value of ε is within the determination pulse amount n1 indicating the error range, the robot's operation is considered normal and continues after the timer is reset. When the absolute value of C is larger than nl, the following criteria are applied. When ε is in this state and the feedback pulse P
When the absolute value of f becomes less than the threshold value n2, which is almost 0, 2
If so, there may be a break in the band wire from the position detector such as an encoder. If the timer is not recognized as operating normally and is not reset even after the timer is set in this state, the timer will exceed the determination time amount t. When these conditions are met, it is considered that an abnormal operation has occurred, and emergency stop processing 22 is executed.

FIG. 6 shows the above operation in a timing chart. When the deviation pulse ε exceeds the criterion n1, the timer reset operation is canceled.

If the deviation pulse falls within the normal range before the timer exceeds the criterion t, the timer is reset. As soon as the timer exceeds the criterion t, it is considered to be malfunctioning.
An emergency stop of robot operation is performed.

FIG. 5 shows a second embodiment of the invention. In the same figure,
The upper and lower flowcharts 28 have the same configuration as the upper and lower flowcharts 70-16 to 20 and 22 of the determination procedure 21 in FIG. The difference between judgment procedure 21 and judgment procedure 28 is that the judgment condition is not the value of deviation pulse ε but the differential value 8 of operation command value Pd.
This is understood by the difference in the sign of the differential value sP (of Pd and the feedback value Pf).Generally, sPd and sPf have different signs and do not continue to scatter; for example, in the case of an incremental encoder, the A-phase and B-phase signal lines This phenomenon occurs when the wires are connected in reverse.In this embodiment, it is possible to prevent the robot from running out of control due to such wiring errors.

Note that FIGS. 3 and 5 are examples, and the present invention is not limited to these examples. Furthermore, it is also possible to make both of them υ independent by the classification means and to perform each determination in one process. In short, the operation command signal and the feedback only need to have a structure in which the conditions that define the abnormal state regarding the problem can be entered in advance and can be determined based on arbitrary criteria.

Effects of the Invention As described above in detail, the present invention has the following effects.

1. If the load changes due to some external factor while a robot or NO-applied machine is in operation, an abnormality can be detected immediately.

2. If a pulse encoder abnormality occurs, such as a pulse encoder power abnormality, disconnection of the output signal line, poor contact, or wiring error, the abnormality can be immediately detected and analyzed to prevent robots from running out of control.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the processing procedure of a robot safety device in one embodiment of the present invention, FIG. 2 is a schematic explanatory diagram of a robot control device to which the present invention is applied, and FIG. 3 is a processing procedure in the first embodiment. 4 is a flowchart of processing in a conventional device, FIG. 5 is a flowchart of processing in the second embodiment, and FIG. 6 is a timing chart in the first embodiment. Name of agent: Patent attorney Toshio Nakao and one other name
2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] a motor that drives an arm of the robot; a control device that converts a program written in accordance with a predetermined rule into a motion command; a drive device that drives at least one motor; a positioning control device that controls the motor drive device based on a feedback signal from a connected position detector; , a judgment information classification means for classifying the characteristics by comparing the judgment information with the classification standard given by the classification standard specifying means; and a judgment information classification means for comparing the information discriminated by the classification means with the abnormality judgment criterion given by the abnormality judgment criterion specifying means. and an abnormality determination means for sending an abnormality determination signal to the motor drive device and the control device to interrupt robot operation.