  This paper proposes a feature-based Visual Servoing (VS) method for insertion
task skills. A camera mounted on the robot's end-effector provides the pose
relative to a cylinder (hole), allowing a contact-free and damage-free search
of the hole and avoiding uncertainties emerging when the pose is computed via
robot kinematics. Two points located on the hole's principal axis and three
mutually orthogonal planes defining the flange's reference frame are associated
with the pose of the hole and the flange, respectively. The proposed VS drives
to zero the distance between the two points and the three planes aligning the
robot's flange with the hole's direction. Compared with conventional VS where
the Jacobian is difficult to compute in practice, the proposed featured-based
uses a Jacobian easily calculated from the measured hole pose. Furthermore, the
feature-based VS design considers the robot's maximum cartesian velocity. The
VS method is implemented in an industrial robot and the experimental results
support its usefulness.
