A fabric-based approach for wearable haptics

In recent years, wearable haptic systems (WHS) have gained increasing attention as a novel and exciting paradigm for human-robot interaction (HRI).These systems can be worn by users, carried around, and integrated in their everyday lives, thus enabling a more natural manner to deliver tactile cues.At the same time, the design of these types of devices presents new issues: the challenge is the correct identification of design guidelines, with the two-fold goal of minimizing system encumbrance and increasing the effectiveness and naturalness of stimulus delivery.Fabrics can represent a viable solution to tackle these issues.They are specifically thought “to be worn”, and could be the key ingredient to develop wearable haptic interfaces conceived for a more natural HRI.In this paper, the author will review some examples of fabric-based WHS that can be applied to different body locations, and elicit different haptic perceptions for different application fields.Perspective and future developments of this approach will be discussed

Spatially Distributed Tactile Feedback for Kinesthetic Motion Guidance

Apraxic stroke patients need to perform repetitive arm movements to regain motor functionality, but they struggle to process the visual feedback provided by typical virtual rehabilitation systems. Instead, we imagine a low cost sleeve that can measure the movement of the upper limb and provide tactile feedback at key locations. The feedback provided by the tactors should guide the patient through a series of desired movements by allowing him or her to feel limb configuration errors at each instant in time. After discussing the relevant motion capture and actuator options, this paper describes the design and programming of our current prototype, a wearable tactile interface that uses magnetic motion tracking and shaftless eccentric mass motors. The sensors and actuators are attached to the sleeve of an athletic shirt with novel plastic caps, which also help focus the vibration on the user\u27s skin. We connect the motors in current drive for improved performance, and we present a full parametric model for their in situ dynamic response (acceleration output given current input)

Supporting Eyes-Free Human–Computer Interaction with Vibrotactile Haptification

The sense of touch is a crucial sense when using our hands in complex tasks. Some tasks we learn to do even without sight by just using the sense of touch in our fingers and hands. Modern touchscreen devices, however, have lost some of that tactile feeling while removing physical controls from the interaction. Touch is also a sense that is underutilized in interactions with technology and could provide new ways of interaction to support users. While users are using information technology in certain situations, they cannot visually and mentally focus completely during the interaction. Humans can utilize their sense of touch more comprehensively in interactions and learn to understand tactile information while interacting with information technology. This thesis introduces a set of experiments that evaluate human capabilities to understand and notice tactile information provided by current actuator technology and further introduces a couple of examples of haptic user interfaces (HUIs) to use under eyes-free use scenarios. These experiments evaluate the benefits of such interfaces for users and concludes with some guidelines and methods for how to create this kind of user interfaces. The experiments in this thesis can be divided into three groups. In the first group, with the first two experiments, the detection of vibrotactile stimuli and interpretation of the abstract meaning of vibrotactile feedback was evaluated. Experiments in the second group evaluated how to design rhythmic vibrotactile tactons to be basic vibrotactile primitives for HUIs. The last group of two experiments evaluated how these HUIs benefit the users in the distracted and eyes-free interaction scenarios. The primary aim for this series of experiments was to evaluate if utilizing the current level of actuation technology could be used more comprehensively than in current-day solutions with simple haptic alerts and notifications. Thus, to find out if the comprehensive use of vibrotactile feedback in interactions would provide additional benefits for the users, compared to the current level of haptic interaction methods and nonhaptic interaction methods. The main finding of this research is that while using more comprehensive HUIs in eyes-free distracted-use scenarios, such as while driving a car, the user’s main task, driving, is performed better. Furthermore, users liked the comprehensively haptified user interfaces

Use of haptics to promote learning outcomes in serious games

Integration of haptics in Serious Games (SGs) remains limited compared to vision and audio. Many works seem to limit haptic interactions to the mimicking of real life feelings. Here, we address this by investigating the use of haptics to promote learning outcomes in serious games. By analyzing how we learn, we proposed a model that identifies three learning outcomes: (1) engage the user with the content of the game, (2) develop technical skills, and (3) develop cognitive skills. For each learning skill, we show how haptic interactions may be exploited. We also show that the proposed model may be used to describe and to evaluate existing methods. It may also help in the designing of new methods that take advantage of haptics to promote learning outcomes

A Virtual Reality Application of the Rubber Hand Illusion Induced by Ultrasonic Mid-Air Haptic Stimulation

Ultrasonic mid-air haptic technologies, which provide haptic feedback through airwaves produced using ultrasound, could be employed to investigate the sense of body ownership and immersion in virtual reality (VR) by inducing the virtual hand illusion (VHI). Ultrasonic mid-air haptic perception has solely been investigated for glabrous (hairless) skin, which has higher tactile sensitivity than hairy skin. In contrast, the VHI paradigm typically targets hairy skin without comparisons to glabrous skin. The aim of this article was to investigate illusory body ownership, the applicability of ultrasonic mid-air haptics, and perceived immersion in VR using the VHI. Fifty participants viewed a virtual hand being stroked by a feather synchronously and asynchronously with the ultrasonic stimulation applied to the glabrous skin on the palmar surface and the hairy skin on the dorsal surface of their hands. Questionnaire responses revealed that synchronous stimulation induced a stronger VHI than asynchronous stimulation. In synchronous conditions, the VHI was stronger for palmar stimulation than dorsal stimulation. The ultrasonic stimulation was also perceived as more intense on the palmar surface compared to the dorsal surface. Perceived immersion was not related to illusory body ownership per se but was enhanced by the provision of synchronous stimulation

Discriminating tissue stiffness with a haptic catheter: Feeling the inside of the beating heart

Catheter devices allow physicians to access the inside of the human body easily and painlessly through natural orifices and vessels. Although catheters allow for the delivery of fluids and drugs, the deployment of devices, and the acquisition of the measurements, they do not allow clinicians to assess the physical properties of tissue inside the body due to the tissue motion and transmission limitations of the catheter devices, including compliance, friction, and backlash. The goal of this research is to increase the tactile information available to physicians during catheter procedures by providing haptic feedback during palpation procedures. To accomplish this goal, we have developed the first motion compensated actuated catheter system that enables haptic perception of fast moving tissue structures. The actuated catheter is instrumented with a distal tip force sensor and a force feedback interface that allows users to adjust the position of the catheter while experiencing the forces on the catheter tip. The efficacy of this device and interface is evaluated through a psychophyisical study comparing how accurately users can differentiate various materials attached to a cardiac motion simulator using the haptic device and a conventional manual catheter. The results demonstrate that haptics improves a user's ability to differentiate material properties and decreases the total number of errors by 50% over the manual catheter system.Engineering and Applied Science

LifeChair: A Conductive Fabric Sensor-Based Smart Cushion for Actively Shaping Sitting Posture.

The LifeChair is a smart cushion that provides vibrotactile feedback by actively sensing and classifying sitting postures to encourage upright posture and reduce slouching. The key component of the LifeChair is our novel conductive fabric pressure sensing array. Fabric sensors have been explored in the past, but a full sensing solution for embedded real world use has not been proposed. We have designed our system with commercial use in mind, and as a result, it has a high focus on manufacturability, cost-effectiveness and adaptiveness. We demonstrate the performance of our fabric sensing system by installing it into the LifeChair and comparing its posture detection accuracy with our previous study that implemented a conventional flexible printed PCB-sensing system. In this study, it is shown that the LifeChair can detect all 11 postures across 20 participants with an improved average accuracy of 98.1%, and it demonstrates significantly lower variance when interfacing with different users. We also conduct a performance study with 10 participants to evaluate the effectiveness of the LifeChair device in improving upright posture and reducing slouching. Our performance study demonstrates that the LifeChair is effective in encouraging users to sit upright with an increase of 68.1% in time spent seated upright when vibrotactile feedback is activated