Design guidelines for generating force feedback on fingertips using haptic interfaces

Manipulation and grasping have key importance in most types of interactions between humans and the world surrounding them [1, 2]. Even if almost all existing haptic interfaces provide a user interaction based on a single contact point, an increased number of contact points, not only allows to display a more natural haptic interaction [3, 4], but also improves the quality of interaction that users can perform in the environment. Haptic exploration is highly dependent on the number of fingers used for exploration of common objects [5], the largest difference appearing between the ‘one finger’ and the ‘two fingers’ conditions [6], and as proven by Jansson et al. [7] by the ability to discriminate a precise tactile pattern during the exploration. In [8], we found an experimental confirmation of this hypothesis: the haptic exploration do not improve with the increase of contact points, from one to two fingers.