W-FYD: a Wearable Fabric-based Display for Haptic Multi-Cue Delivery and Tactile Augmented Reality

Despite the importance of softness, there is no evidence of wearable haptic systems able to deliver controllable softness cues. Here, we present the Wearable Fabric Yielding Display (W-FYD), a fabric-based display for multi-cue delivery that can be worn on user's finger and enables, for the first time, both active and passive softness exploration. It can also induce a sliding effect under the finger-pad. A given stiffness profile can be obtained by modulating the stretching state of the fabric through two motors. Furthermore, a lifting mechanism allows to put the fabric in contact with the user's finger-pad, to enable passive softness rendering. In this paper, we describe the architecture of W-FYD, and a thorough characterization of its stiffness workspace, frequency response and softness rendering capabilities. We also computed device Just Noticeable Difference in both active and passive exploratory conditions, for linear and non-linear stiffness rendering as well as for sliding direction perception. The effect of device weight was also considered. Furthermore, performance of participants and their subjective quantitative evaluation in detecting sliding direction and softness discrimination tasks are reported. Finally, applications of W-FYD in tactile augmented reality for open palpation are discussed, opening interesting perspectives in many fields of human-machine interaction

FingerTac - A Wearable Tactile Thimble for Mobile Haptic Augmented Reality Applications

ingerTac is a novel concept for a wearable augmented haptic thimble. It makes use of the limited spatial discrimination capabilities of vibrotactile stimuli at the skin and generates tactile feedback perceived at the bottom center of a fingertip by applying simultaneous vibrations at both sides of the finger. Since the bottom of the finger is thus kept free of obstruction, the device is well promising for augmented haptic applications, where real world interactions need to be enriched or amalgamated with virtual tactile feedback. To minimize its lateral dimension, the vibration actuators are placed on top of the device, and mechanical links transmit the vibrations to the skin. Two evaluation studies with N=10 participants investigate (i) the loss of vibration intensity through these mechanical links, and (ii) the effect of lateral displacement between stimulus and induced vibration. The results of both studies support the introduced concept of the FingerTac

Design of a wearable fingertip haptic device for remote palpation: Characterisation and interface with a virtual environment

© 2018 Tzemanaki, Al, Melhuish and Dogramadzi. This paper presents the development of a wearable Fingertip Haptic Device (FHD) that can provide cutaneous feedback via a Variable Compliance Platform (VCP). The FHD includes an inertial measurement unit, which tracks the motion of the user's finger while its haptic functionality relies on two parameters: pressure in the VCP and its linear displacement towards the fingertip. The combination of these two features results in various conditions of the FHD, which emulate the remote object or surface stiffness properties. Such a device can be used in tele-operation, including virtual reality applications, where rendering the level of stiffness of different physical or virtual materials could provide a more realistic haptic perception to the user. The FHD stiffness representation is characterised in terms of resulting pressure and force applied to the fingertip created through the relationship of the two functional parameters - pressure and displacement of the VCP. The FHD was tested in a series of user studies to assess its potential to create a user perception of the object's variable stiffness. The viability of the FHD as a haptic device has been further confirmed by interfacing the users with a virtual environment. The developed virtual environment task required the users to follow a virtual path, identify objects of different hardness on the path and navigate away from "no-go" zones. The task was performed with and without the use of the variable compliance on the FHD. The results showed improved performance with the presence of the variable compliance provided by the FHD in all assessed categories and particularly in the ability to identify correctly between objects of different hardness

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

A Wearable Fabric-based display for haptic multi-cue delivery

Softness represents one of the most informative haptic properties, which plays a fundamental role in both everyday tasks and more complex procedures. Thus, it is not surprising that much effort has been devoted to designing haptic systems able to suitably reproduce this information. At the same time, wearability has gained an increasing importance as a novel paradigm to enable a more effective and naturalistic human robot interaction. Capitalizing upon our previous works on grounded softness devices, in this paper we present the Wearable Fabric Yielding Display (W-FYD), a fabric-based tactile display for multi-cue delivery that can be worn by user's finger. W-FYD enables to implement both passive and active tactile exploration. Different levels of stiffness can be reproduced by modulating the stretching state of a fabric through two DC motors. An additional vertical degree of freedom is implemented through a lifting mechanism, which enables to convey softness stimuli to the user's finger pad. Furthermore, a sliding effect on the finger can be also induced. Experiments with humans show the effectiveness of W-FYD for haptic multi-cue delivery

Feasibility and effect of low-cost haptics on user immersion in virtual environments

Since the later 1990s research into Immersion, Presence and Interactivity in the context of digital media has been steadily evolving into an exciting area of experimentation, fuelled by advances in the visual, audio and tracking capabilities of Virtual Reality (VR) equipment, thanks to these improvements studies into the effectiveness of this equipment in producing an immersive experience are now possible. This is most commonly achieved by measuring the perceived level of Presence experienced by participants in virtual environments, with the higher the sense of Presence created, the more effective a VR system is deemed to be. However, due to the current limitations of Haptic interaction methods investigation into the role that touch plays in generating this sense of Presence is somewhat restricted. Following a structured process of design and research work, this project presents a new approach to creating Haptic Interaction by deploying a Haptic Prototyping Toolkit that enables Passive Haptic Interactions in Virtual Environments. The findings of this work provide the foundations for future research into the development of interaction methods of this type