Electricity: motive power systems – Positional servo systems – Program- or pattern-controlled systems
Patent
1992-03-19
2000-09-05
Ip, Paul
Electricity: motive power systems
Positional servo systems
Program- or pattern-controlled systems
318573, 318578, 414730, 901 47, 2940704, G05B 19403, B25J 916, G06F 1562
Patent
active
061148245
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a calibration method for a visual sensor, and more particularly, to a method for calibrating a visual sensor attached to a robot by means of a calibration jig which is movably supported by means of another robot.
2. Description of the Related Art
Conventionally known are robot systems which perform assembly operation, palletizing operation, etc. for workpieces on a working line by utilizing visual information from one or more visual sensors. Also known is a technique for movably holding a visual sensor by means of a robot arm to cope with the variation of the workpiece position. According to the robot systems of this type, the visual sensor is calibrated to make sensor coordinate values to correspond to robot coordinate values before robot operation, in order to make the visual information available for the robot operation. Conventionally, for example, a camera (visual sensor in general) mounted on the robot arm is calibrated by using an exclusive-use calibration jig which is set within the range of the camera.
Generally, however, the conventional calibration jig is large-sized, and therefore, requires a wide setting space. This requirement is particularly awkward when the calibration jig is set on the working line. Further, accurately setting the conventional calibration jig takes time, so that a special jig setting mechanism must be provided for accurately setting the calibration jig.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a calibration method in which a visual sensor attached to a robot can be calibrated easily, quickly, and accurately without using a mechanism for accurately setting a jig or a wide jig setting space.
In order to achieve the above object, according to the present invention, (a) first calibration pattern data including the coordinate values of a calibration jig, movably supported by means of a robot and formed of a pattern member, on a common coordinate system is generated; (b) second calibration pattern data including the coordinate values of the calibration jig on a visual sensor coordinate system is generated in accordance with visual information data for the calibration jig obtained by means of a visual sensor mounted on another robot; and (c) the visual sensor is calibrated on the basis of the first and second calibration pattern data.
According to the present invention, as described above, the visual sensor can be calibrated by using the calibration jig mounted on one robot and the visual sensor mounted on the other robot. The calibration jig, which is formed of the pattern member, is smaller in size and simpler in construction than a conventional jig, and is movably held by means of the robot, so that the jig can be located easily, quickly, and accurately in a desired position without requiring a wide jig setting space. Also, the visual sensor can be calibrated easily, quickly, and accurately on the basis of the first calibration pattern data including the coordinate values of the calibration jig on the common coordinate system and the second calibration pattern data generated in accordance with the visual information data for the calibration jig obtained by means of the visual sensor and including the coordinate values of the calibration jig on the visual sensor coordinate system. Thus, there is no need of any special mechanism for accurately positioning the calibration jig.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view showing a robot system for carrying out a calibration method for a visual sensor according to one embodiment of the present invention;
FIG. 2 is an enlarged plan view showing a pattern plate of FIG. 1 in detail;
FIG. 3 is a schematic view showing a case in which a robot mounted with a camera is moved toward a workpiece after calibration is finished;
FIG. 4 is a partial schematic view showing a modification of the robot system of FIG. 1;
FIG. 5 is a partial schematic view showing another modification of the robot system; a
REFERENCES:
patent: 3890552 (1975-06-01), Devol et al.
patent: 4146924 (1979-03-01), Birk et al.
patent: 4441817 (1984-04-01), Pryor
patent: 4481592 (1984-11-01), Jacobs et al.
patent: 4639878 (1987-01-01), Day et al.
patent: 4712183 (1987-12-01), Shiroshita et al.
patent: 4753569 (1988-06-01), Pryor
patent: 4796200 (1989-01-01), Pryor
patent: 4851905 (1989-07-01), Pryor
patent: 4853771 (1989-08-01), Witriol et al.
patent: 4954762 (1990-09-01), Miyake et al.
patent: 4979135 (1990-12-01), Moy
patent: 4983797 (1991-01-01), McAllister et al.
patent: 5020001 (1991-05-01), Yamamoto et al.
patent: 5023426 (1991-06-01), Prokosch et al.
patent: 5034904 (1991-07-01), Moy
patent: 5041991 (1991-08-01), Fujiki
patent: 5083073 (1992-01-01), Kato
patent: 5086262 (1992-02-01), Hariki et al.
patent: 5148591 (1992-09-01), Pryor
Fanuc Ltd.
Ip Paul
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