cluding robotics, developmental medicine, and biomechanics,
each focusing on different aspects of action. In a recent
survey (Feix et al. 2013) reported 45 grasp types in the literature,
of which only 33 were found valid. In this work, we use
a categorization into six grasping types. First we distinguish,
according to the most commonly used classification (based
on functionality) into power and precision grasps (Jeannerod
1984). Power grasping is used when the object needs to be
held firmly in order to apply force, such as “grasping a knife
to cut”; precision grasping is used in order to do fine grain
actions that require accuracy, such as “pinch a needle”. We
then further distinguish among the power grasps, whether
they are spherical, or otherwise (usually cylindrical), and
we distinguish the latter according to the grasping diameter,
into large diameter and small diameter ones. Similarly,
we distinguish the precision grasps into large and small diameter
ones. Additionally, we also consider a Rest position
(no grasping performed). Table 1 illustrates our grasp categories.
We denote the list of these six grasps as G in the
remainder of the paper.