Method for calibrating tool centre point for industrial robot system

A method for calibrating a tool centre point of a tool for an industrial robot system comprising a cross beam sensor that has a first beam and a second beam which are angled to each other with a vertex angle greater than zero and cross each other at a crossing point, including:

• (a) relatively moving a first part of said tool and a cross beam sensor by said industrial robot with translational motion in an orientation so that said first part of said tool interrupts said first beam of said cross beam sensor, moves along the first beam direction from the interruption point, and interrupts said second beam of said cross beam sensor at said crossing point of said cross beam sensor;
• (b) recording a second posture of said industrial robot where said first part of said tool interrupts said second beam of said cross beam sensor at said crossing point of said cross beam sensor;
• (c) relatively moving a second part of said tool and said cross beam sensor by said industrial robot with translational motion in said orientation so that said second part of said tool interrupts said first/second beam of said cross beam sensor, moves along the first/second beam direction from the interruption point, and interrupts said second/first beam of said cross beam sensor at said crossing point of said cross beam sensor;
• (d) recording a fourth posture of said industrial robot where said second part of said tool interrupts said second beam of said cross beam sensor at said crossing point of said cross beam sensor;
• (e) calculating the tool orientation in consideration of said second posture and said fourth posture of said industrial robot;
• and
• (f) relatively moving said tool and said cross beam sensor by said industrial robot so that said tool centre point of said tool interrupts said crossing point of said cross beam sensor in consideration of said tool orientation and either the second posture or the fourth posture of said industrial robot.