A 3-DIMENSIONAL MEASUREMENT SYSTEM FOR ROBOT APPLICATIONS

This paper presents a 3D noncontacting sensor system designed to measu re the position and orientation of a robot end effector. This measurem ent system includes two parts: a tridimensional object including four spheres placed along the axes of a tetrahedron and a set of three orth ogonally pointed cameras. The purpose is to design a measurement syste m characterized by easy relationships in order to satisfy real-time co nstraints. The system has been used in two experiments: first, to cali brate a parallel robot and validate the geometrical control performanc e, then as an exteroceptive sensor in an assembly task. The system com putes position and orientation of the tetrahedron in 100 ms time. The position and orientation accuracy are, respectively, 0.6 nm and 0.2 de g in a workspace, being a cube with 0.3 m sides.