JPH0259284A - Control method for industrial robot - Google Patents

Abstract

PURPOSE:To shorten a tact time by detecting the positional deviation from a teaching position by detecting the present position of the specified point of a work objective work by an operation mode and rewriting the contents of the teaching position of after correction of a memory by calculating the contents of the teaching position of the memory for correction. CONSTITUTION:The present position of the specified point of a work objective work 8 is detected by a work detector 5 in an operation mode and the positional deviation from the teaching position of the present position of the specified point thereof is detected. The memory contents of a memory 3 is re-written to the contents of the teaching position of after correction based on the positional deviation of the work objective work 8. As a result, the initial position of the work objective work 8 is detected at the lot changing over time, and the detection of the position of the work objective work 8 becomes unnecessary thereafter only by rewriting the contents of the memory 3 based thereon. Consequently, the tact time can be shortened by the time spent for the positional detection.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention automatically corrects the positional deviation of the workpiece between the teaching mode and the operation mode when performing welding etc. using an industrial robot, for example. The present invention relates to a control system for industrial robots that performs work while making manual corrections.

[Conventional technology]

When performing work using an industrial robot, the problems are the positional accuracy of the workpiece relative to the industrial robot and the dimensional accuracy of the workpiece (0 position performance 5 dimensional accuracy when the robot arm is poor) In order to correct the position of the workpiece, it is necessary to detect the position of the workpiece. A television camera is most often used to detect the position of the workpiece. However, when performing arc welding, for example, there are often restrictions on the allowable space depending on the shape of the workpiece itself or the fixture for fixing the workpiece. Therefore, a method is used to determine the position by using a consumable electrode, that is, a wire, and detecting when this wire comes into contact with the welding base metal (for example, Japanese Patent Publication No. 56-5
(See Publication No. 634). Although this method takes time to detect the workpiece to be worked on, it does not have any problems such as the above-mentioned space problem, spatter problem, fume, gas, light, etc., and has an excellent feature. There is.

[Problem to be solved by the invention]

However, when an industrial robot performs work while detecting a positional shift of a workpiece, there is a problem in that the takt time becomes long.

Therefore, an object of the present invention is to provide a control method for an industrial robot that can shorten the takt time when the industrial robot performs work.

[Means to solve the problem]

The control method for the industrial robot of the present invention includes at least one
A robot arm consisting of a rotational or linear axis that is greater than the axis and a position detector that detects the position of the axis, a control device that has a rewritable memory and moves the robot arm according to the stored contents of this memory, and a robot arm that This is a method for controlling an industrial robot, which consists of a workpiece detector that is attached to it and detects the position of the workpiece being worked on.

This industrial robot control system divides operations into at least a teaching mode and a driving mode.

First, in the teaching mode, the position, posture, movement command, etc. of the robot arm are taught to the control device and written into the memory.

Next, in the operation mode, the workpiece detector detects the current position of a specific point on the workpiece, detects the amount of positional deviation of the current position of the specific point on the workpiece with respect to the taught position, and detects the position of the specific point on the workpiece. The contents of the taught position written in the memory are corrected based on the amount of positional deviation, the contents stored in the memory are rewritten to the contents of the corrected taught position, and the contents of the taught position after the correction written in the memory are calculated. The robot arm is controlled by a control device.

[For production]

In the configuration of the present invention, in the operation mode, the workpiece detector detects the current position of a specific point on the workpiece to be worked on, and detects the amount of positional deviation of the current position of the specific point on the workpiece to be worked on with respect to the taught position. It turns out. Then, the contents of the teaching position written in the memory are corrected and calculated based on the positional deviation amount of the specific point of the workpiece, and the contents stored in the memory are rewritten with the contents of the corrected teaching position.

As a result, the contents of the taught position written in the memory are automatically corrected in accordance with the positional shift of the workpiece due to loft switching, for example, and the position of the workpiece when the loft is changed is automatically corrected. By simply detecting this and rewriting the contents of the memory based on it, there is no need to detect the position of the workpiece after that, and the takt time can be shortened by the time required to detect the position.

〔Example〕

An embodiment of the present invention will be described based on FIGS. 1 and 2. As shown in FIG. 1, the control system for this industrial robot consists of a robot arm 1 consisting of at least one rotational or linear axis, a position detector 4 that detects the position of the axis, and a rewritable robot arm 1. A control device 7 that has a memory 3 and a calculation device 6 and moves the robot arm l according to the stored contents of the memory 3; and a workpiece detection device that is attached to the robot arm l and detects the position of the workpiece 8 to be worked on the workpiece mounting table 9. This method controls an industrial robot consisting of a child 5 and a teaching device 2.

This industrial robot control system divides operations into at least a teaching mode and a driving mode.

First, in the teaching mode, the position and posture of the robot arm 1 necessary for working on the workpiece 8 are determined.

Operation instructions and the like are taught to the control device 7 using the teaching device 2 and written into the memory 3.

Next, in the operation mode, the workpiece detector 5 detects the current position of the specific point on the workpiece 8 to be worked on, and the control 111 device 7 detects the teaching position of the current position of the specific point on the workpiece 8 to be worked on (in the teaching mode, The content of the teaching position written in the memory 3 based on the amount of positional deviation of the specific point of the workpiece 8 to be worked is detected by the arithmetic unit 6. A correction calculation is performed, the contents stored in the memory 3 are rewritten to the contents of the corrected taught position, and the robot arm 1 is controlled by the control device 7 according to the contents of the corrected taught position written in the memory 3. 9 is a base on which the robot arm 1 is installed.

In this embodiment, the current position of a specific point on the workpiece 8 to be worked is detected by the workpiece detector 5 in the operation mode,
The control device 7 detects the amount of positional deviation between the current position of the specific point of the workpiece 8 and the taught position. Then, the content of the teaching position written in the memory 3 is corrected and calculated based on the positional deviation amount of the specific point of the workpiece 8 to be worked on by the arithmetic unit 6, and the content stored in the memory 3 becomes the content of the teaching position after the correction. It will be rewritten.

As a result, for example, the workpiece 8 to be worked on due to lot switching.
The content of the teaching position written in the memory 3 is automatically corrected according to the positional deviation of By simply rewriting the contents, the operation of detecting the position of the workpiece 8 to be worked on is no longer necessary, and the takt time can be shortened by the time required for position detection.

The control system for this industrial robot will be explained in detail below based on FIG. 2. FIG. 2 shows a specific embodiment of this invention.

In FIG. 2, the workpiece 8 indicated by a solid line is
In the teaching mode, it shows the position when teaching. Further, the work object 8 indicated by a broken line indicates the position when the work is actually performed in the driving mode.

In the teaching mode, the teaching position of the robot arm 1 is
For example, there are seven points from point 21 to P7 point f, and the position data of these seven points is written into the memory 3 as the taught position.

Point 21 is the operation start point, points 22 and 25 are work position detection points for detecting the position of the workpiece 8 to be worked on (corresponding to specific points in the claims), point 23 is the start point of work, and point 24. is the movement preparation point for point 26, point 26 is the work end point, and point 27 is the movement end point.

For example, at the time of lot switching, the robot arm 1 detects the position of the workpiece 8 to be worked on by sensing it with the workpiece detector 5 in the operation mode.
Welding is performed by performing all operations from points 28 to 27, and the teaching position data from points 22 to 27 written in the memory 3 is transferred from the 22 points after the position detection of the workpiece 8 to P7. Rewrite each data up to point ′.

Next, when operating, perform operations other than the detection operation of the workpiece 8, that is, point p%, point 23, point P6', point P
Execute the operation at point 7' to perform welding. In other words, the next operation will be performed at the corrected position and in which the takt time is shortened by the time required for the detection operation of the workpiece 8 to be operated.

〔Effect of the invention〕

According to the control method of the industrial robot of the present invention, in the operation mode, the workpiece detector detects the current position of a specific point on the workpiece, and calculates the amount of positional deviation of the current position of the specific point on the workpiece with respect to the taught position. The content of the teaching position detected and written to the memory is calculated based on the amount of positional deviation of a specific point on the workpiece, and the content stored in the memory is rewritten to the content of the corrected teaching position. At the time of switching, the position of the first workpiece to be worked on is detected and the contents of the memory are rewritten based on it. After that, there is no need to detect the position of the workpiece to be worked on, reducing takt time by the time required to detect the position. can do.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of an industrial robot used in an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the operation of the embodiment. 1... Robot arm, 2... Teaching device, 3...
Memory, 4... Position detector, 5... Work detector,
6...Calculation member, 7...Control device, 8...Workpiece diagram to be worked on

Claims (1)

Scope of Claims: A robot arm comprising at least one rotary or linear axis and a position detector for detecting the position of the axis; and a rewritable memory, the robot arm according to the contents of the memory. A control system for an industrial robot that controls an industrial robot comprising a control device that moves an arm and a workpiece detector that is attached to the robot arm and detects the position of a workpiece to be worked on, the method comprising at least a teaching mode and an operation mode. In the teaching mode, the robot arm's position, posture, movement command, etc. are taught to the control device and written into the memory, and in the operation mode, the workpiece is identified by the workpiece detector. detecting the current position of the point, detecting the amount of positional deviation of the current position of the specific point of the workpiece to be worked on with respect to the taught position, and writing in the memory based on the amount of positional deviation of the specific point of the workpiece to be worked on; Calculate correction of the contents of the taught position, rewrite the contents stored in the memory with the contents of the corrected taught position, and control the robot arm with the control device according to the contents of the corrected taught position written in the memory. A control method for industrial robots that is characterized by: