Electric heating – Metal heating – By arc
Patent
1994-02-23
1996-02-27
Shaw, Clifford C.
Electric heating
Metal heating
By arc
901 42, B23K 9127
Patent
active
054950902
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a teaching play-back type welding robot which automatically recognizes a welding point on a workpiece to be welded and the posture of the later so as to perform self-teaching of an operation program while it autonomously follows a welding line.
BACKGROUND OF THE INVENTION
Most of presently available welding robots are of a teaching play-back type. These known robots have required that several operation programs be taught to a single robot in order to cope with multi-kind and small quantity production. Further, it has been desired to provide measures for reducing the manhours of effective teaching of an operation program to an welding robot in view of a lack of skilled workers for teaching a robot.
A teaching method which is widely used, in general, at the present time, requires that a teaching worker use manipulating switches in a manipulation box for designating a motion of a robot so as to cause the robot to take a predetermined motion while the teaching worker monitors the motion of the robot in order to teach an operation program. This method presents problems such as requiring a complex teaching operation for a workpiece to be welded which requires a curved welding line, direction change or the like, and further requires repetitions trial operations in order to obtain a desired motion for the robot. Accordingly, it takes a long time for the teaching of the robot.
In view of the above, various teaching measures that don't use a manipulation box as mentioned above, have been proposed, and have been practically used.
Of the above-mentioned measures, one is the so-called off-line teaching method for teaching an absolute position on the coordinates set on a working field including a robot. For example, there have been proposed a method of teaching an absolute position with the use of computer simulation, a method in which a position teaching unit incorporating several light emitting elements, instead of a torch, is moved along a welding line on a workpiece to be welded, and light emitted therefrom is detected by image sensors fixed to a working field so as to teach a robot, as disclosed in Japanese Laid-Open Patent No. 60-136806 or Japanese Patent Publication No. 64-4875. In these methods, a high degree of accuracy is reburied for positioning a robot. Further, the confirmation of the presence of any interference between a robot arm, a welding torch or a welding cable and a workpiece to be welded, a peripheral jig or the like is required.
Further, there are other methods in which teaching is made while a robot is actually operated. A first one of these methods is a direct teaching method in which a robot sometimes detects and stores in memory its motion while a worker who grips a welding torch or a grip part which a dummy of the torch fixed to the distal end part of a robot arm, leads the torch or the like so as to follow a welding line. For example, Japanese Laid-Open Patent No. 56-85106 discloses a method of detecting the motion, in which a force detector for detecting a direction in which the worker leads the grip part and a force for leading the grip part is provided, and the position and posture of the tip end of the torch is computed from an output signal from the detector. Since the direct teaching method allows the worker to manipulate the robot with his institution without being aware of the coordinates set on a robot, it is easily accomplished by the teaching worker. However, the installed force detector may interfere with a workpiece or a jig so that it cannot be manipulated. Further, certain shapes of a workpiece forces the worker to take an unreasonable posture. Further, there is a possible risk such that the worker may accidentally touch the robot and be harmed.
A second method allows a robot to automatically recognize a welding start point and a weld line with the use of a sensor so that the robot teaches while it autonomously follows the welding line. This method can eliminate the necessity of confirmation of the interfere
REFERENCES:
patent: 4215299 (1980-07-01), Edwin et al.
patent: 4298784 (1981-11-01), Schmall
patent: 4356378 (1982-10-01), Cloos et al.
patent: 4441011 (1984-04-01), Nomura et al.
patent: 4590577 (1986-05-01), Nio et al.
patent: 4704513 (1987-11-01), Sugitani et al.
patent: 4760241 (1988-07-01), Sugitani et al.
Mukai Yasushi
Takahashi Makoto
Matsushita Electric - Industrial Co., Ltd.
Shaw Clifford C.
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