A method for calibration of a working point (TCP) for tools on industrial
robots with a calibration device includes the use of at least two light
barriers with an azimuth angle (.alpha.) greater than zero at an angle to
each other and intersecting at an intersection point. The method includes
fixing set TCP positional coordinates for a set working point for the
tool, relative to a tool reference point and a TCP coordinate system
relative to the working point, moving the tool to the set working point
with relation to the TCP coordinate system through the light barriers,
such that the tool tip interrupts the light barriers, recording actual
TCP positional coordinates determining the difference between the set TCP
positional coordinates for the interruption of the light barriers for a
set working point and the corresponding recorded actual TCP positional
coordinates for the actual working point, calculating the actual working
point from the set working point for the number of levels of light
barriers from the differences and the known position and azimuth angles
(a) of the light barriers.