Wearable Tactile Display Research Articles

How to Make the Skin Contact Area Controllable by Optical Calibration in Wearable Tactile Displays of Softness.

Virtual reality systems may benefit from wearable (fingertip-mounted) haptic displays capable of rendering the softness of virtual objects. According to neurophysiological evidence, the easiest reliable way to render a virtual softness is to generate purely tactile (as opposed to kinaesthetic) feedback to be delivered via a finger-pulp-interfaced deformable surface. Moreover, it is necessary to control not only the skin indentation depth by applying quasi-static (non-vibratory) contact pressures, but also the skin contact area. This is typically impossible with available devices, even with those that can vary the contact area, because the latter cannot be controlled due to the complexity of sensing it at high resolutions. This causes indetermination on an important tactile cue to render softness. Here, we present a technology that allows the contact area to be open-loop controlled via personalised optical calibrations. We demonstrate the solution on a modified, pneumatic wearable tactile display of softness previously described by us, consisting of a small chamber containing a transparent membrane inflated against the finger pulp. A window on the device allowed for monitoring the skin contact area with a camera from an external unit to generate a calibration curve by processing photos of the skin membrane interface at different pressures. The solution was validated by comparisons with an ink-stain-based method. Moreover, to avoid manual calibrations, a preliminary automated procedure was developed. This calibration strategy may be applied also to other kinds of displays where finger pulps are in contact with transparent deformable structures.

Design and prototype of a wearable fingertip tactile display using 6DoF parallel link mechanism

Design and prototype of a wearable fingertip tactile display using 6DoF parallel link mechanism

Wearable Tactile Display Based on Thermal Expansion of Nichrome Wire.

A wearable tactile display needs to be compact and lightweight, and ideally should be able to present vibration, force, and temperature information to the hand. In many contexts spatially distributed tactile information is needed such as when identifying the shape of objects. In this paper, a multi-element tactile display is described based on the thermal expansion and contraction of nichrome wire. The device comprises elastic rods that are pulled by nichrome wires (30 μm in diameter). When an electrical current is applied to the wire, displacement of the elastic rod occurs with thermal elongation of the wire. The wire cools quickly and vibration results. The nichrome wire that is the basis of this display overcomes many of the material restrictions associated with shape memory alloys that have often been used for thermally driven tactile displays. Experiments that characterized the performance of the tactile display indicated that perceptible vibrations up to 320 Hz can be presented. Psychophysical studies revealed that both position and movement cues can be displayed effectively with the device. A miniaturized version of this display for wearable applications has been built and undergone preliminary evaluation.

2A2-W08 圧覚提示と電気触覚刺激の組み合わせによる装着型触覚ディスプレイの試作

We propose a wearable tactile display using transcutaneous electric nerve stimulation and tactile force. This tactile display is suitable for virtual reality applications, for users can wear this device and it doesn't disturb user's hand movement. This device has a high space resolution and users can differentiate edge and flat surface of virtual objects.

Wearable Tactile Display of Landmarks and Direction for Pedestrian Navigation

This research investigates representation techniques for spatial and related information in the design of tactile displays for pedestrian navigation systems. The paper reports on a user survey that identified and categorized landmarks used in pedestrian navigation in the urban context. The results show commonalities of landmark use in urban spaces worldwide. The survey results were then used in an experimental study that compared two tactile techniques for landmark representation using one or two actuators. Techniques were compared on 4 measures: distinguishability, learnability, memorability, and user preferences. Results from the lab-based evaluation showed that users performed equally well using either technique to represent just landmarks alone. However, when landmark representations were presented together with directional signals, performance with the one-actuator technique was significantly reduced while performance with the two-actuator approach remained unchanged. The results of this ongoing research programme can be used to help guide design for presenting key landmark information on wearable tactile displays.

119302 超音波振動を用いたアクティブタッチ触感の呈示手法の提案(OS17 ロボティクス・メカトロニクス1,オーガナイズド・セッション)

When we display the texture of virtual 3D objects, it is required to display both tactile and force information at the same time. Although some force displays are commercially available, a wearable tactile display should be realized display tactile information together with force information. Hence this paper proposes a novel wearable tactile display aiming for the integration with force display. Active touch is required to display tactile information more sensitively. That means it is need to recreate active touch when we display tactile information using wearable tactile display. To realize such a device, we used the squeeze film effect for tactile display, occurred by an ultrasonic vibration. In addition to this, we propose to move a sheet between finger and ultrasonic vibrator. First, we develop device using the method we propose. Then, we verified the usability of the wearable tactile display by experiments.

1P1-E26 超音波振動を用いた装着型触感ディスプレイ

When we display the texture of virtual 3D objects, it is required to display both tactile and force information at the same time. Although some force displays are commercially available in order to display tactile information together with force information, a wearable tactile display should be realized. Hence this paper proposes a novel wearable tactile display aiming for the integration with force display. To realize such a device, we used the squeeze film effect for tactile display, occurred by an ultrasonic vibration. First, we developed an ultrasonic vibrator for tactile display. The ultrasonic vibrator is required to be small and produce enough force to display the texture. Then, we develop a wearable tactile display using the ultrasonic vibrator. Finally, we verified the usability of the wearable tactile display by experiments.

Tactual displays for wearable computing

This paper provides a general overview of tactual displays (i.e., devices that communicate to a user through the sense of touch) and issues concerning the development of such displays for wearable computing. A wearable tactile directional display is presented. It takes advantage of a sensory phenomenon called ‘sensory saltation’ and simulates directional lines and simple geometric patterns dynamically. Initial results indicate that this information is intuitive and easy to interpret even for first-time users, and interpretations are highly consistent among observers. Several applications of this tactile directional display for wearable computing are proposed.

Wearable tactile sensory aid providing information on voice pitch and intonation patterns

A wearable tactile sensory aid which presents a vibratory signal representative of voice pitch and intonation patterns to the skin. The vibratory signal consists of a constant amplitude square wave having a frequency equal to, or some fraction of, the fundamental frequency of the speech input. The vibratory signal is applied as a tactile stimulus, and is displaced along a linear array of transducers in contact with the skin in proportion to the logarithm of the fundamental frequency. Accordingly, the wearable tactile display encodes the fundamental frequency to provide both frequency of actuation and spatial indications thereof.

A wearable tactile intonation display for the deaf

A wearable device is described which represents the fundamental frequency of voiced sounds as the locus of pitch-synchronous vibrotactile stimulation of the skin. The pitch extractor, which accepts inputs from either a microphone or an accelerometer, uses a combination of low-pass filtering and peak detection to generate a square wave whose frequency is half that of the fundamental frequency of the speech signal. Using a shift register and a clock, the first half of each cycle is timed, the result determining which of eight output channels is actuated during the second half. The output transducer array consists of eight miniature solenoids mounted in a small plastic box. The electronics package is worn on a belt and the solenoid array is mounted on the forearm. The system is powered by thee 9 V NiCad batteries and runs for 2 to 3 h between charges. Experiments with normally hearing subjects confirmed that single channel changes of stimulus location can be detected with relative ease. It was also demonstrated that the system permits discrimination among some of the principal intonation contours of English. The potential value of this device in the rehabilitation of hearing-impaired children is currently under investigation.