JPH0498402A - Industrial robot - Google Patents

Abstract

PURPOSE:To execute safety disposition such as to self-diagnose the abnormality of a deviation and to stop an operation by operating a difference between position command data and position feedback data in a stand-by stated and outputting an abnormality signal when an operation value exceeds a reference deviation value. CONSTITUTION:A memory 5 to which the reference deviation value is registered and a control part 4 operating the difference between position command data and position feedback data in the stand-by state and outputting the abnormality signal when the operation value exceeds the reference deviation value are provided. Whenever a system is in the stand-by state, the deviation is judged to be more than the reference deviation value registered in the memory 5. When it is more than the reference deviation value, the abnormality signal is given. Thus, safety disposition such as to stop the operation of the robot can be executed with the abnormality signal as an opportunity. Then, the deviation (position precision) is diagnosed whenever the robot itself comes to a stand-by position. When it is abnormal, disposition is given so as to control oneself.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a teaching/reproducing type industrial robot, and particularly to an industrial robot having a function of self-managing positional accuracy.

[Conventional technology J Conventionally, teaching/reproduction type industrial robots have been used as automatic machines that perform tasks such as painting and welding in place of humans, and are capable of adapting to flexible/pull for various types of workpieces by changing the operating program. has been done.

This type of robot is determined by position feedback data from position detectors installed on each axis of the robot body and the taught movement program data, and the position at which the robot body is commanded to move at that moment The robot body is controlled by a control method (position feedback control method) that operates the robot body according to the operation program by sending a signal to the actuator of the robot body so as to eliminate the difference with the data (position command data).

With such a control method, theoretically, when the robot body is stopped, there is no lag between the actual position and the commanded position, and the position feedback data and position command data are The difference (deviation) from “
It should be "O".If the deviation at the time of stopping is large, it means that the arm of the robot body is interfering with an obstacle such as a peripheral device and is in an abnormal state, such as its movement being restricted. In particular, if the deviation value when the operation program is taught changes when the operation program is actually played back and the operation is performed, the operation as taught may not be possible. This means that the robot body may move in an unexpected path and cause interference with other equipment, which is dangerous.

Therefore, conventionally, these position command data and position feedback data can be displayed on the display screen of the robot control device for each axis, and the deviations thereof can be checked at the time of maintenance.

``Problem to be solved by the invention'' However, with the above-mentioned management method, changes in deviation may be overlooked due to worker negligence or carelessness, and operation may continue with degraded work quality. There was a risk that the main body of the robot would operate with a large misalignment, leading to interference with other equipment.

The present invention has been made in view of the above conventional problems, and it is an object of the present invention to provide an industrial robot that has a self-management function that self-diagnoses abnormalities in deviation values and takes safety measures such as stopping operation. The purpose is

``Means for Solving the Problems'' The industrial robot of the present invention is a teaching/reproducing type industrial robot, which has a memory in which a standard deviation value is registered, and a position command data and a position feedback data in a standby state. The present invention is characterized in that it is further provided with a control section that calculates the difference between the values and outputs an abnormal signal if the calculated value exceeds the reference deviation value.

"Operation" With the above configuration, each time the standby state is entered, it is determined whether the deviation is greater than or equal to the reference deviation value registered in the memory, and if it is greater than or equal to the reference deviation value, an abnormality signal is issued. Therefore, this abnormal signal can be used as a trigger to take safety measures such as stopping the robot's operation, and the deviation (positional accuracy) can be diagnosed every time the robot moves to the standby position. If so, you will need to take safety measures and manage yourself.

"Example" An example of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram showing the overall configuration of the industrial robot of this embodiment.

This robot is composed of a control device 1 and a robot main body 2, and operates in cooperation with a peripheral device 3 consisting of, for example, a workpiece conveyance device or a detection device to work on a painting work line or the like.

The control device 1 controls signals between a central control section 4 (control section) that controls the operation of the entire control device, a memory 5 in which operation program data or standard deviation values are registered, and the robot body 2 or peripheral devices 3. and a servo that receives device command data and sends control signals to the actuators of the robot body 2 via the input/output unit 6 to servo control the robot body 2. A control section 7, a buzzer 8 that emits an alarm sound when receiving a command (abnormal signal) from the central control section 4, and an operation section 9 for inputting various signals to the central control section 4 to operate the control device l. , a display section 10 that displays operating status, alarms, various data, etc.

The robot body 2 is, for example, a 6-axis multi-joint type, and includes an actuator and a position detector for each axis, and is controlled by a signal output from the servo control unit 7 described above, and has a coating attached to its wrist 2a. The work is done by moving the gun etc.

The signal from the position detector of the robot body 2 is input as position feedback data to the servo control section 7 or the central control section 4 via the input/output section 6.

Here, the reference deviation value registered in the memory 5 is an upper limit value that indicates an abnormality if the absolute value of the difference between the position command data and the position feedback data (hereinafter referred to as deviation) increases beyond this value, and there is no danger. There are two types of values: values that require adjustment (hereinafter referred to as alarm values) and values that are much larger than this alarm value and require immediate stoppage of operation to prevent danger (hereinafter referred to as danger values). Yes, both have operation section 9
It is possible to register it in the memory 5 by operating .

Then, the central control section 4 calculates the deviation every time immediately before starting operation in the standby state, and if the absolute value of this deviation exceeds the alarm value, an abnormality signal is sent to the display section 10 or the buzzer 8. It has the function of outputting a warning value and stopping the operation of the robot if the dangerous value is exceeded. (Here, the standby state refers to a state in which the robot main body 2 finishes working on one workpiece and maintains a standby posture to wait for the next workpiece to be carried in.) In other words, the central control unit 4 When the state is reached, the following steps 81 to S9 are executed.

[Step Sl] When a cycle start signal (for example, a workpiece loading signal output from a workpiece detector of a peripheral device and a signal that triggers execution of an operation program) is input,
Before operating the robot body 2, the process advances to step S2 and subsequent processing is performed.

If the cycle start signal is not input, the operation is stopped at step S1.

[Step S2] The position feedback data inputted at this point from the robot body 2 is read, and the process proceeds to step S3.

[Step S3] The absolute value of the difference, that is, the deviation, between the position feedback data read in step S2 and the position command data currently output to the servo control section 7 is calculated, and the process proceeds to step S4.

[Step S4] Determine whether the absolute value of the deviation obtained in step S3 exceeds the danger value registered in the memory 5. If it does, proceed to step S5; if not, proceed to step S4. Proceed to S7.

[Step S5] The drive system of the robot body 2 is stopped (specifically, the output of the control signal from the servo control unit 7 is stopped), and the operation of the robot body 2 is stopped.

Proceed to step S6.

[Step S6] A display indicating an abnormality such as "excessive deviation value" is displayed on the display unit 10, an abnormality signal is sent to the buzzer 8, the buzzer 8 is sounded for a certain period of time, and the process is ended.

[Step S7] Determine whether the absolute value of the deviation obtained in Step S3 exceeds the alarm value registered in the memory 5. If it does, proceed to Step S8; if not, proceed to Step S8. Proceed to step S9.

[Step S8] Display a message on the display unit 10 indicating the necessity of maintenance, such as "large deviation value", send an abnormality signal to the buzzer 8, and make the buzzer 8 sound for a certain period of time, and then proceed to step S.
Proceed to step 9.

[Step S9] The robot body 2 starts the operation program according to the cycle start signal, and the process ends.

According to the industrial robot of this embodiment described above, the deviation is the standard deviation value (danger value or alarm value) that is registered in the memory 5 every time immediately before starting operation from the standby state.
It is determined whether the threshold value is exceeded, and if the danger value is exceeded, the operation is stopped and an alarm sound is output and an alarm display is performed. Further, if the danger value is not exceeded but the alarm value is exceeded, only an alarm sound is output and an alarm is displayed.

In other words, the robot itself self-diagnoses the deviation (positional accuracy) immediately before starting operation from the standby position, and if an abnormality is found, the above measures are taken, so positional deviations that occur due to long-term operation, etc. are overlooked. Since the machine will stop when there is excessive positional deviation, etc., it is safe and prevents work defects, and it also has the effect of ensuring that the operator is informed when maintenance of the mouth and mouth is required. .

Note that the standard deviation value in the present invention may be set to an appropriate value depending on the operation accuracy required depending on the content of the work and the characteristics of the robot itself. Since this self-management by the robot may be unnecessary, for example, if "O" is registered in the standard deviation value, the central control unit 4
The self-management function may be configured so that it does not perform the processing of the step knobs 81 to S9, and the self-management function may be disabled by setting a reference deviation value.

"Effects of the Invention" According to the industrial robot of the present invention, each time it enters the standby state, it is determined whether the deviation is greater than or equal to the standard deviation value registered in the memory, and if it is greater than or equal to the standard deviation value, it issues an alarm, etc. safety measures can be taken. In other words, each time the robot itself reaches the standby position, it self-diagnoses the deviation (positional accuracy) and takes the above safety measures if it is abnormal, so positional deviations that occur due to long-term operation will not be overlooked, ensuring safety. This has the effect of not only preventing the occurrence of work defects, but also ensuring that the operator is informed of when maintenance is required.

[Brief explanation of the drawing]

1 to 2 are diagrams showing an embodiment of the present invention,
Figure 1 is a block diagram showing the overall configuration of an industrial robot;
FIG. 2 is a flowchart showing the operation of the control section. 4...Control unit (central control unit), 5...
memory.

Claims (1)

[Claims] The teaching/reproduction type industrial robot calculates the difference between a memory in which a standard deviation value is registered and position command data and position feedback data in a standby state, and the calculated value exceeds the standard deviation value. An industrial robot comprising: and a control unit that outputs an abnormal signal.