114 research outputs found
Electrostatic Friction Displays to Enhance Touchscreen Experience
Touchscreens are versatile devices that can display visual content and receive touch input, but they lack the ability to provide programmable tactile feedback. This limitation has been addressed by a few approaches generally called surface haptics technology. This technology modulates the friction between a user’s fingertip and a touchscreen surface to create different tactile sensations when the finger explores the touchscreen. This functionality enables the user to see and feel digital content simultaneously, leading to improved usability and user experiences. One major approach in surface haptics relies on the electrostatic force induced between the finger and an insulating surface on the touchscreen by supplying high AC voltage. The use of AC also induces a vibrational sensation called electrovibration to the user. Electrostatic friction displays require only electrical components and provide uniform friction over the screen. This tactile feedback technology not only allows easy and lightweight integration into touchscreen devices but also provides dynamic, rich, and satisfactory user interfaces. In this chapter, we review the fundamental operation of the electrovibration technology as well as applications have been built upon
Tactile Roughness Perception of Virtual Gratings by Electrovibration
Realistic display of tactile textures on touch screens is a big step forward
for haptic technology to reach a wide range of consumers utilizing electronic
devices on a daily basis. Since the texture topography cannot be rendered
explicitly by electrovibration on touch screens, it is important to understand
how we perceive the virtual textures displayed by friction modulation via
electrovibration. We investigated the roughness perception of real gratings
made of plexiglass and virtual gratings displayed by electrovibration through a
touch screen for comparison. In particular, we conducted two psychophysical
experiments with 10 participants to investigate the effect of spatial period
and the normal force applied by finger on roughness perception of real and
virtual gratings in macro size. We also recorded the contact forces acting on
the participants' finger during the experiments. The results showed that the
roughness perception of real and virtual gratings are different. We argue that
this difference can be explained by the amount of fingerpad penetration into
the gratings. For real gratings, penetration increased tangential forces acting
on the finger, whereas for virtual ones where skin penetration is absent,
tangential forces decreased with spatial period. Supporting our claim, we also
found that increasing normal force increases the perceived roughness of real
gratings while it causes an opposite effect for the virtual gratings. These
results are consistent with the tangential force profiles recorded for both
real and virtual gratings. In particular, the rate of change in tangential
force () as a function of spatial period and normal force followed
trends similar to those obtained for the roughness estimates of real and
virtual gratings, suggesting that it is a better indicator of the perceived
roughness than the tangential force magnitude.Comment: Manuscript received June 25, 2019; revised November 15, 2019;
accepted December 11, 201
Multi-physics modelling and experimental validation of electrovibration based haptic devices
Electrovibration tactile displays exploit the polarisation of the finger pad, caused by an insulated high voltage supplied plate. This results in electrostatic attraction, which can be used to modulate the users' perception of an essentially flat surface and induce texture sensation. Two analytical models of electrovibration, based on parallel plate capacitor assumption, are demonstrably taken and assessed by comparisons with experimental results published in literature. In addition, an experimental setup was developed to measure the electrostatic force between the finger pad and a high voltage supplied plate in a static and out-of-contact state in order to support the use of parallel plate capacitor model. Development, validation, and application of a computational framework for modelling tactile scenarios on real and virtual surfaces rendered by electrovibration technique is presented. The framework incorporates fully parametric model in terms of materials and geometry of the finger pad, virtual and real surfaces, and can serve as a tool for virtual prototyping and haptic rendering in electrovibration tactile displays. This is achieved by controlling the applied voltage signal in order to guarantee similar lateral force cues in real and simulated surfaces
Modern Applications of Electrostatics and Dielectrics
Electrostatics and dielectric materials have important applications in modern society. As such, they require improved characteristics. More and more equipment needs to operate at high frequency, high voltage, high temperature, and other harsh conditions. This book presents an overview of modern applications of electrostatics and dielectrics as well as research progress in the field
Expressive haptics for enhanced usability of mobile interfaces in situations of impairments
Designing for situational awareness could lead to better solutions for
disabled people, likewise, exploring the needs of disabled people could lead to
innovations that can address situational impairments. This in turn can create
non-stigmatising assistive technology for disabled people from which eventually
everyone could benefit. In this paper, we investigate the potential for
advanced haptics to compliment the graphical user interface of mobile devices,
thereby enhancing user experiences of all people in some situations (e.g.
sunlight interfering with interaction) and visually impaired people. We explore
technical solutions to this problem space and demonstrate our justification for
a focus on the creation of kinaesthetic force feedback. We propose initial
design concepts and studies, with a view to co-create delightful and expressive
haptic interactions with potential users motivated by scenarios of situational
and permanent impairments.Comment: Presented at the CHI'19 Workshop: Addressing the Challenges of
Situationally-Induced Impairments and Disabilities in Mobile Interaction,
2019 (arXiv:1904.05382
Haptics: Science, Technology, Applications
This open access book constitutes the proceedings of the 12th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2020, held in Leiden, The Netherlands, in September 2020. The 60 papers presented in this volume were carefully reviewed and selected from 111 submissions. The were organized in topical sections on haptic science, haptic technology, and haptic applications. This year's focus is on accessibility
Exploring Fingers' Limitation of Texture Density Perception on Ultrasonic Haptic Displays
International audienceRecent research in haptic feedback is motivated by the crucial role that tactile perception plays in everyday touch interactions. In this paper, we describe psychophysical experiments to investigate the perceptual threshold of individual fingers on both the right and left hand of right-handed participants using active dynamic touch for spatial period discrimination of both sinusoidal and square-wave gratings on ultra-sonic haptic touchscreens. Both one-finger and multi-finger touch were studied and compared. Our results indicate that users' finger identity (index finger, middle finger, etc.) significantly affect the perception of both gratings in the case of one-finger exploration. We show that index finger and thumb are the most sensitive in all conditions whereas little finger followed by ring are the least sensitive for haptic perception. For multi-finger exploration, the right hand was found to be more sensitive than the left hand for both gratings. Our findings also demonstrate similar perception sensitivity between multi-finger exploration and the index finger of users' right hands (i.e. dominant hand in our study), while significant difference was found between single and multi-finger perception sensitivity for the left hand
Contact geometry and mechanics predict friction forces during tactile surface exploration
International audienceWhen we touch an object, complex frictional forces are produced, aiding us in perceiving surface features that help to identify the object at hand, and also facilitating grasping and manipulation. However, even during controlled tactile exploration, sliding friction forces fluctuate greatly, and it is unclear how they relate to the surface topography or mechanics of contact with the finger. We investigated the sliding contact between the finger and different relief surfaces, using high-speed video and force measurements. Informed by these experiments, we developed a friction force model that accounts for surface shape and contact mechanical effects, and is able to predict sliding friction forces for different surfaces and exploration speeds. We also observed that local regions of disconnection between the finger and surface develop near high relief features, due to the stiffness of the finger tissues. Every tested surface had regions that were never contacted by the finger; we refer to these as " tactile blind spots ". The results elucidate friction force production during tactile exploration, may aid efforts to connect sensory and motor function of the hand to properties of touched objects, and provide crucial knowledge to inform the rendering of realistic experiences of touch contact in virtual reality
Haptics: Science, Technology, Applications
This open access book constitutes the proceedings of the 12th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2020, held in Leiden, The Netherlands, in September 2020. The 60 papers presented in this volume were carefully reviewed and selected from 111 submissions. The were organized in topical sections on haptic science, haptic technology, and haptic applications. This year's focus is on accessibility
- …