PalmEx: Adding Palmar Force-Feedback for 3D Manipulation with Haptic Exoskeleton Gloves

“PalmEx” consists in a haptic exoskeleton glove augmented with an actuated palmar interface for perceiving force-feedback in VR. Left: (a) The user’s palm is unencumbered prior to interaction. (b) The palmar interface goes towards her palm while the user starts gesturing a grasp. (c) When engaging the grasp, the user perceives force-feedback from both the exoskeleton and the palmar interface. Right: A user is exploring the environment with PalmEx.

Haptic exoskeleton gloves are a widespread solution for providing force-feedback in Virtual Reality (VR), especially for 3D
object manipulations. However, they are still lacking an important feature regarding in-hand haptic sensations: the palmar contact. In this paper, we present PalmEx, a novel approach which incorporates palmar force-feedback into exoskeleton gloves to improve the overall grasping sensations and manual haptic interactions in VR. PalmEx’s concept is demonstrated through a self-contained hardware system augmenting a hand exoskeleton with an encountered palmar contact interface – physically encountering the users’ palm. We build upon current taxonomies to elicit PalmEx’s capabilities for both the exploration and manipulation of virtual objects. We first conduct a technical evaluation optimising the delay between the virtual interactions and their physical counterparts. We then empirically evaluate PalmEx’s proposed design space in a user study (n=12) to assess the potential of a palmar contact for augmenting an exoskeleton. Results show that PalmEx offers the best rendering capabilities to perform believable grasps in VR. PalmEx highlights the importance of the palmar stimulation, and provides a low-cost solution to augment existing high-end consumer hand exoskeletons.