JPS63229293A - Robot-operation abnormality detector - 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 Industrial Application) The present invention relates to a robot operation abnormality detection device for detecting abnormal conditions during robot operation.

(Prior art) Conventional methods for detecting abnormalities in robot motion include (1) Japanese Patent Application Laid-Open No. 57-209506, (2) Japanese Patent Application Laid-open No. 60-108.
No. 904, (3) JP-A-60-195603, and the like.

Hereinafter, an outline of these prior art techniques will be explained using figures.

(1) FIG. 5 is a configuration diagram of such a conventional abnormality detection device for a robot.

In this figure, 1 is a storage unit for storing data taught in advance, 2 is a calculation unit that reads data from the storage unit 1 and performs predetermined calculations to generate command pulses that determine the robot's motion. A flip-flop circuit receives the output of the calculation section 2 at a set terminal S; 4 is a servo control section for receiving the output from the output terminal Q of the flip-flop circuit 3 and operating the servo motor 5; 6 is a servo control section for operating the servo motor 5; This is a detection section that detects the amount of operation, and its output is fed back to the servo control section 4 to form a closed loop in the servo control system. 7 is a determination circuit for receiving the outputs of the calculation unit 2 and the flip-flop circuit 3 and determining whether or not the output command pulse of the calculation unit 2 has been reliably received by the servo control unit 4; is supplied to the arithmetic unit 2 and also to the servo control unit 4 to stop these operations. In this way, the transmission of control signals from the calculation section to the servo control section is constantly monitored, and the command pulse is The servo controller is configured to immediately stop operation if the signal is not completely transmitted to the servo control section.

(2) Next, FIG. 6 is a block diagram of another conventional robot abnormality detection device.

In this figure, 8 is the robot's position detector, 9 is the CPU
(Central processing unit), 10 is a correction position data calculation unit, 11 is an input data memory, 12 is a correction calculation unit, 13 is an output data memory, 14 is an adder/subtractor, 15 is a comparator, and 16 is a permissible upper and lower limit value memory. The position feed bank signal xf is output from the position detector 8 to the CPU 9 and the adder/subtractor 14, and the CPU 9 inputs the position command value Xc, designated moving speed V, and follow-up delay amount α to the corrected position data calculation unit 10. This corrected position data calculation unit 10
outputs the position command value Xc, designated moving speed V, and follow-up delay amount α to the adder/subtractor 14. This adder/subtractor 14 inputs the absolute value ΔXA of the difference between the position feedback signal Xf and the corrected position data XA to the comparator 15. This comparator 15 compares the permissible upper and lower limit values Tv inputted in advance with the absolute value ΔX every unit time, and outputs an abnormal signal to the CPU 9 when the values are equal to or larger than the absolute value ΔX, and the trajectory of the robot is It is configured to perform abnormality detection.

(3) Also, although not shown, Japanese Patent Application Laid-Open No. 60-195603
No. 1 discloses a prior art technique that immediately renders the robot inoperable if the signal line of the rotary encoder or position detector is disconnected or shorted.

As described above, in the prior art, an abnormality in a servo system control device or an abnormality in positioning based on time is detected.

(Problems to be Solved by the Invention) As described above, in the conventional method, even in the case of an abnormal operation of the robot, the detection is limited to abnormalities in the control signal due to breakage or short circuit of the signal cable inside the control device, etc. There are problems such as abnormalities cannot be detected until a large positioning error occurs in the robot's operation. When trying to detect an abnormal state during operation, such as an abnormality in the robot arm or when the robot arm touches something, there is a problem in that it is only possible to detect it after the amount of abnormality has become considerably large. .

If such an abnormality in robot operation cannot be detected promptly, there are problems such as damage to the actuator or robot mechanism itself, or fire due to heat generation.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems, quickly and accurately detect abnormalities in robot operation, and provide a highly safe robot operation abnormality detection device.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a driving force memory that stores in advance the driving force during the normal operation of the robot in a motion abnormality detection device for a robot that performs sequence motions. means, speed storage means for storing in advance the speed of the robot during normal operation, driving force detection means for detecting the driving force during actual operation of the robot, and speed detection means for detecting the speed during actual operation of the robot. , speed comparison means for comparing the set speed stored in the speed storage means and the actual speed from the speed detection means; and a speed comparison means for comparing the set speed stored in the speed storage means with the actual speed from the speed detection means; The driving force comparison means for comparing the driving force with the driving force stored in the driving force storage means, and the notification means operated by a predetermined output signal from the driving force comparison means are provided.

(Function) According to the present invention, as configured as described above, one or more arbitrary set speeds ( below,
The robot's driving force is determined each time the sampling speed is reached during one sequence operation, and the driving force and the corresponding order of the driving force data stored during normal operation are determined. Make a comparison with
If the error deviates from an arbitrarily set error range, it is determined that an abnormal operation has occurred and a notification is issued.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a robot operation abnormality detection device according to the present invention, FIG. 2 is a diagram showing the memory state of the robot's driving force, and FIG. 3 is a schematic configuration diagram of a robot device to which the present invention is applied. FIG. 4 is a block diagram of a control system for one operating axis of the robot device.

First, as shown in FIG. 3, this robot device includes a robot mechanism section [horizontal articulated robot NISCARA (SCAR^) type robot] having a plurality of joints, and a robot that controls this robot mechanism section 21. It consists of a control device 22.

This robot device stores a motion sequence of a finite length of time and repeatedly executes the motion.

As shown in FIG. 4, this robot device basically includes a rotary encoder 31 as a position detection means and an electric motor 30 as an actuator on each axis of a robot mechanism section 21 (see FIG. 3).

Moreover, inside the robot control device 22 (see FIG. 3),
A host control device 32 that controls the entire control device, a position command device 33 that sequentially outputs target positions, and a position error signal that takes the difference between the position signal from the rotary encoder 31 and the position signal from the position command device 33. Based on the signals from the first difference device 34 and the rotary encoder 31, the F/V converter 37 generates a speed signal and calculates the difference between the position error signal and the speed signal from the F/V converter 37. It consists of a second difference device 35 that outputs a speed command signal and an amplifier 36 that amplifies the output signal from the second difference device 35.

In the present invention, as shown in FIG. 1, the following means are taken to detect abnormal conditions in the operation of the robot. Note that only one motion axis will be explained here.

A power detector 40 that measures the electric power sent to the electric motor 30 as a driving force detection means, a driving force storage device 43 for storing the driving force during normal operation, and a driving force storage device 43
A driving force comparator 44 that compares the driving force data stored in the drive force with the driving force at the time of sequence execution, a speed memory device 41 that stores the speed for creating the timing for comparing the driving forces, and the speed memory 41. A speed comparator 42 is provided to compare the speed stored in the bag rI 141 and the actual speed obtained via the rotary encoder 31 and the F/V converter 37.

Here, the sampling speed for comparing the driving forces is simultaneously input to the speed storage device 41 during the sequence operation. In addition, data related to the sequence operation of the robot device is input to the driving force storage device 43, and when the robot device is tried in an actual operating state (at this time, a human being usually monitors the robot device, and normal operation is performed). The driving forces are stored in the timing and order when the sampling speed is reached. That is, as shown in FIG. 2, for example, the sampling speed is set to 81 and 32, and driving force data a to driving force data h are stored in order.

Next, the operation of this robot motion abnormality detection device will be explained.

This robot device is used for assembly work, etc., and its actuator normally operates in one of four states: a stopped state, an accelerated state, a constant speed state, and a decelerated state, as shown in Figure 2. While holding it, move the position of the effector at the tip (robot hand, etc.).

As shown in FIG. 2, the actuator of this robot device passes through the sampling speed memorized at the time of teaching during acceleration and deceleration states. When the sampling speed is passed, the speed comparator 42 outputs an instruction to sample the driving force. The power detector 40 samples the driving force (in this case, electric power) applied to the electric motor 30, which is an actuator, in accordance with this instruction signal.

The driving force comparator 44 compares the sampled driving force with the stored driving force data during normal operation in the corresponding order. If the compared result is within the error range memorized at the time of teaching, it is determined that the operation is normal, and if it is outside the error range, it is determined that the operation is abnormal, and an abnormality detection signal Sa is sent to the host controller 32, and various alarms are issued. and displays to notify that fact. In this embodiment, when an abnormal operation is determined, the operation of the robot mechanism section is stopped, and a display indicating that the operation is abnormal is displayed on the display section of the robot control device.

Equipped with such an abnormality detection device, it is possible to quickly and accurately detect abnormalities in operation such as failures in mechanical brakes installed in robot mechanisms, damage to bearings, and handling of non-target objects. can do.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described above in detail, according to the present invention, the binary values of the robot's driving force and its operating speed are monitored, and the robot's driving force is determined based on the sampling speed stored during normal operation. By comparing the actual measured value with the reference value stored during normal operation, it is possible to detect abnormal conditions in the robot's operation, such as a failure in the robot mechanism or handling a work other than the planned work. can be done quickly and accurately.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a robot motion abnormality detection device according to the present invention, FIG. 2 is a diagram showing a memory state of the driving force of the robot, and FIG. 3 is a schematic configuration diagram of a robot device to which the present invention is applied. Figure 4 is a block diagram of the control system for one operating axis of the robot device, Figure 5 is a configuration diagram of a conventional robot abnormality detection device, and Figure 6 is a configuration diagram of another conventional robot abnormality detection device. be. 21... Robot mechanism unit, 22... Robot control device, 30... Electric motor, 31... Rotary encoder, 32... Upper control device, 33... Position command device, 34... First differentiator, 35... Second differentiator, 36... Amplifier, 37... F/V converter, 40
...Power detector, 41...Speed storage device, 42...
・Speed comparator, 43... Driving force storage device, 44...
Driving force comparator.

Claims (1)

[Scope of Claims] A robot operation abnormality detection device for detecting an abnormal state of the operation of a robot that performs a sequence operation, comprising: (a) driving force storage means for storing in advance the driving force during normal operation of the robot; (b) (c) Driving force detection means for detecting the driving force during actual operation of the robot; (d) Speed for detecting the speed during actual operation of the robot. (e) speed comparison means for comparing the set speed stored in the speed storage means and the actual speed from the speed detection means; (f) based on an output signal from the speed comparison means; (g) a driving force comparing means for comparing the actual driving force from the driving force detecting means and the driving force stored in the driving force storing means; and (g) an alarm activated by a predetermined output signal from the driving force comparing means. 1. A robot operation abnormality detection device comprising: means.