Design of a wearable skin stretch cutaneous device for the upper limb

This paper presents a novel cutaneous device capable of providing independent skin stretches at the palmar, dorsal, ulnar, and radial sides of the arm. It consists of a lightweight bracelet with four servo motors. Each motor actuates a cylindrical shaped end-effector that is able to rotate, generating skin stretch stimuli. To understand how to control and wear the device on the forearm to evoke the most effective cutaneous sensations, we carried out perceptual experiments evaluating its absolute and differential thresholds. Finally, we carried out an experiment of haptic navigation to assess the effectiveness of our device as a navigation feedback system to guide a desired rotation and translation of the forearm. Results demonstrate an average rotation and translation error of 1.87○ and 2.84 mm, respectively. Moreover, all the subjects found our device easy to wear and comfortable. Nine out of ten found it effective in transmitting navigation information to the forearm

Can wearable haptic devices foster the embodiment of virtual limbs?

Increasing presence is one of the primary goals of virtual reality research. A crucial aspect is that users are capable of distinguishing their self from the external virtual world. The hypothesis we investigate is that wearable haptics play an important role in the body experience and could thereby contribute to the immersion of the user in the virtual environment. A within-subject study (n=32) comparing the embodiment of a virtual hand with different implementations of haptic feedback (force feedback, vibrotactile feedback, and no haptic feedback) is presented. Participants wore a glove with haptic feedback devices at thumb and index finger. They were asked to put virtual cubes on a moving virtual target. Touching a virtual object caused vibrotactile-feedback, force-feedback or no feedback depending on the condition. These conditions were provided both synchronously and asynchronously. Embodiment was assessed quantitatively with the proprioceptive drift and subjectively via a questionnaire. Results show that haptic feedback significantly improves the subjective embodiment of a virtual hand and that force feedback leads to stronger responses to certain subscales of subjective embodiment. These outcomes are useful guidelines for wearable haptic designer and represent a basis for further research concerning human body experience, in reality, and in virtual environments