2,268 research outputs found
Tactile graphical display for the visually impaired information technology applications
This paper presents an interactive tactile graphical display, for the visually impaired information technology access applications. The display consists of a matrix of dots. Each dot is an electro rheological micro actuator. The actuator design and development process is presented in this paper. Prototype size 124x4 dots was manufactured. An advanced software tools and embedded system based on voltage matrix manipulation has been developed, to provide the display near real time control. The experimental tests carried out into the developed prototype showed that each actuator of the matrix was able to provide a vertical movement of 0.7 mm and vertical holding force of 100 to 200 mN. The stroke and dynamic response tests showed the practicability of the developed tactile display, for the visually impaired information technology applications
A Review of Smart Materials in Tactile Actuators for Information Delivery
As the largest organ in the human body, the skin provides the important
sensory channel for humans to receive external stimulations based on touch. By
the information perceived through touch, people can feel and guess the
properties of objects, like weight, temperature, textures, and motion, etc. In
fact, those properties are nerve stimuli to our brain received by different
kinds of receptors in the skin. Mechanical, electrical, and thermal stimuli can
stimulate these receptors and cause different information to be conveyed
through the nerves. Technologies for actuators to provide mechanical,
electrical or thermal stimuli have been developed. These include static or
vibrational actuation, electrostatic stimulation, focused ultrasound, and more.
Smart materials, such as piezoelectric materials, carbon nanotubes, and shape
memory alloys, play important roles in providing actuation for tactile
sensation. This paper aims to review the background biological knowledge of
human tactile sensing, to give an understanding of how we sense and interact
with the world through the sense of touch, as well as the conventional and
state-of-the-art technologies of tactile actuators for tactile feedback
delivery
Haptic Stylus and Empirical Studies on Braille, Button, and Texture Display
This paper presents a haptic stylus interface with a
built-in compact tactile display module and an impact module
as well as empirical studies on Braille, button, and texture
display. We describe preliminary evaluations verifying the
tactile display's performance indicating that it can
satisfactorily represent Braille numbers for both the normal
and the blind. In order to prove haptic feedback capability of
the stylus, an experiment providing impact feedback mimicking
the click of a button has been conducted. Since the developed
device is small enough to be attached to a force feedback
device, its applicability to combined force and tactile
feedback display in a pen-held haptic device is also
investigated. The handle of pen-held haptic interface was
replaced by the pen-like interface to add tactile feedback
capability to the device. Since the system provides
combination of force, tactile and impact feedback, three
haptic representation methods for texture display have been
compared on surface with 3 texture groups which differ in
direction, groove width, and shape. In addition, we evaluate
its capacity to support touch screen operations by providing
tactile sensations when a user rubs against an image displayed
on a monitor
Tactile Arrays for Virtual Textures
This thesis describes the development of three new tactile stimulators for active
touch, i.e. devices to deliver virtual touch stimuli to the fingertip in response to
exploratory movements by the user. All three stimulators are designed to provide
spatiotemporal patterns of mechanical input to the skin via an array of contactors,
each under individual computer control. Drive mechanisms are based on
piezoelectric bimorphs in a cantilever geometry.
The first of these is a 25-contactor array (5 × 5 contactors at 2 mm spacing). It
is a rugged design with a compact drive system and is capable of producing strong
stimuli when running from low voltage supplies. Combined with a PC mouse,
it can be used for active exploration tasks. Pilot studies were performed which
demonstrated that subjects could successfully use the device for discrimination of
line orientation, simple shape identification and line following tasks.
A 24-contactor stimulator (6 × 4 contactors at 2 mm spacing) with improved
bandwidth was then developed. This features control electronics designed to transmit
arbitrary waveforms to each channel (generated on-the-fly, in real time) and
software for rapid development of experiments. It is built around a graphics tablet,
giving high precision position capability over a large 2D workspace. Experiments
using two-component stimuli (components at 40 Hz and 320 Hz) indicate that
spectral balance within active stimuli is discriminable independent of overall intensity,
and that the spatial variation (texture) within the target is easier to detect
at 320 Hz that at 40 Hz.
The third system developed (again 6 × 4 contactors at 2 mm spacing) was a lightweight modular stimulator developed for fingertip and thumb grasping tasks;
furthermore it was integrated with force-feedback on each digit and a complex
graphical display, forming a multi-modal Virtual Reality device for the display of
virtual textiles. It is capable of broadband stimulation with real-time generated
outputs derived from a physical model of the fabric surface. In an evaluation study,
virtual textiles generated from physical measurements of real textiles were ranked
in categories reflecting key mechanical and textural properties. The results were
compared with a similar study performed on the real fabrics from which the virtual
textiles had been derived. There was good agreement between the ratings of the
virtual textiles and the real textiles, indicating that the virtual textiles are a good
representation of the real textiles and that the system is delivering appropriate
cues to the user
A survey of haptics in serious gaming
Serious gaming often requires high level of realism for training and learning purposes. Haptic technology has been proved to be useful in many applications with an additional perception modality complementary to the audio and the vision. It provides novel user experience to enhance the immersion of virtual reality with a physical control-layer. This survey focuses on the haptic technology and its applications in serious gaming. Several categories of related applications are listed and discussed in details, primarily on haptics acts as cognitive aux and main component in serious games design. We categorize haptic devices into tactile, force feedback and hybrid ones to suit different haptic interfaces, followed by description of common haptic gadgets in gaming. Haptic modeling methods, in particular, available SDKs or libraries either for commercial or academic usage, are summarized. We also analyze the existing research difficulties and technology bottleneck with haptics and foresee the future research directions
Tac-tiles: multimodal pie charts for visually impaired users
Tac-tiles is an accessible interface that allows visually impaired users to browse graphical information using tactile and audio feedback. The system uses a graphics tablet which is augmented with a tangible overlay tile to guide user exploration. Dynamic feedback is provided by a tactile pin-array at the fingertips, and through speech/non-speech audio cues. In designing the system, we seek to preserve the affordances and metaphors of traditional, low-tech teaching media for the blind, and combine this with the benefits of a digital representation. Traditional tangible media allow rapid, non-sequential access to data, promote easy and unambiguous access to resources such as axes and gridlines, allow the use of external memory, and preserve visual conventions, thus promoting collaboration with sighted colleagues. A prototype system was evaluated with visually impaired users, and recommendations for multimodal design were derived
Vibratory tactile display for textures
We have developed a tactile display that produces vibratory stimulus to a fingertip in contact with a vibrating tactor matrix. The display depicts tactile surface textures while the user is exploring a virtual object surface. A piezoelectric actuator drives the individual tactor in accordance with both the finger movement and the surface texture being traced. Spatiotemporal display control schemes were examined for presenting the fundamental surface texture elements. The temporal duration of vibratory stimulus was experimentally optimized to simulate the adaptation process of cutaneous sensation. The selected duration time for presenting a single line edge agreed with the time threshold of tactile sensation. Then spatial stimulus disposition schemes were discussed for representation of other edge shapes. As an alternative means not relying on amplitude control, a method of augmented duration at the edge was investigated. Spatial resolution of the display was measured for the lines presented both in perpendicular and parallel to a finger axis. Discrimination of texture density was also measured on random dot textures
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