A teaching position correcting device which can easily correct, with high
precision, teaching positions after shifting at least one of a robot and
an object worked by the robot. Calibration is carried out using a vision
sensor (i.e., CCD camera) that is mounted on a work tool. The vision
sensor measures three-dimensional positions of at least three reference
marks not aligned in a straight line on the object. The vision sensor is
optionally detached from the work tool, and at least one of the robot and
the object is shifted. After the shifting, calibration (this can be
omitted when the vision sensor is not detached) and measuring of
three-dimensional positions of the reference marks are carried out gain.
A change in a relative positional relationship between the robot and the
object is obtained using the result of measuring three-dimensional
positions of the reference marks before and after the shifting
respectively. To compensate for this change, the teaching position data
that is valid before the shifting is corrected. The robot can have a
measuring robot mechanical unit having a vision sensor, and a separate
working robot mechanical unit that works the object. In this case,
positions of the working robot mechanical unit before and after the
shifting, respectively, are also measured.
