Soft Pneumatic Fingertip Actuator Incorporating a Dual Air Chamber to Generate Multi-Mode Simultaneous Tactile Feedback

A complete set of diverse haptic feedbacks is essential for a highly realistic and immersive virtual environment. In this sense, a multi-mode haptic interface that simultaneously generates multiple kinds of haptic signals is highly desirable. In this paper, we propose a new silicone-made pneumatically controlled fingertip actuator to render pressure and vibrotactile feedback concurrently to offer a realistic and effective haptic sensation. A new silicone-based stacked dual-layer air chamber was designed. The volume of the chambers is controlled by pneumatic valves with compressed air tanks. The top/upper air chamber renders vibration feedback, whereas the bottom/lower air chamber renders pressure feedback. The proposed silicone-made fingertip actuator is designed so that it can be easily worn at the fingertips. To demonstrate the potential of the system, a virtual environment for rendering three different types of haptic textures was implemented. Extensive performance evaluation and user studies were carried out to demonstrate the proposed actuator’s effectiveness compared to an actuator with single vibrotactile feedback.

Effects of Using Vibrotactile Feedback on Sound Localization by Deaf and Hard-of-Hearing People in Virtual Environments

Sound source localization is important for spatial awareness and immersive Virtual Reality (VR) experiences. Deaf and Hard-of-Hearing (DHH) persons have limitations in completing sound-related VR tasks efficiently because they perceive audio information differently. This paper presents and evaluates a special haptic VR suit that helps DHH persons efficiently complete sound-related VR tasks. Our proposed VR suit receives sound information from the VR environment wirelessly and indicates the direction of the sound source to the DHH user by using vibrotactile feedback. Our study suggests that using different setups of the VR suit can significantly improve VR task completion times compared to not using a VR suit. Additionally, the results of mounting haptic devices on different positions of users’ bodies indicate that DHH users can complete a VR task significantly faster when two vibro-motors are mounted on their arms and ears compared to their thighs. Our quantitative and qualitative analysis demonstrates that DHH persons prefer using the system without the VR suit and prefer mounting vibro-motors in their ears. In an additional study, we did not find a significant difference in task completion time when using four vibro-motors with the VR suit compared to using only two vibro-motors in users’ ears without the VR suit.

Neural Coding of Vibration Intensity

Vibrotactile feedback technology has become widely used in human–computer interaction due to its low cost, wearability, and expressiveness. Although neuroimaging studies have investigated neural processes associated with different types of vibrotactile feedback, encoding vibration intensity in the brain remains largely unknown. The aim of this study is to investigate neural processes associated with vibration intensity using electroencephalography. Twenty-nine healthy participants (aged 18–40 years, nine females) experienced vibrotactile feedback at the distal phalanx of the left index finger with three vibration intensity conditions: no vibration, low-intensity vibration (1.56 g), and high-intensity vibration (2.26 g). The alpha and beta band event-related desynchronization (ERD) as well as P2 and P3 event-related potential components for each of the three vibration intensity conditions are obtained. Results demonstrate that the ERD in the alpha band in the contralateral somatosensory and motor cortex areas is significantly associated with the vibration intensity. The average power spectral density (PSD) of the peak period of the ERD (400–600 ms) is significantly stronger for the high- and low-vibration intensity conditions compared to the no vibration condition. Furthermore, the average PSD of the ERD rebound (700–2,000 ms) is significantly maintained for the high-vibration intensity compared to low-intensity and no vibration conditions. Beta ERD signals the presence of vibration. These findings inform the development of quantitative measurements for vibration intensities based on neural signals.

Highly pixelated, untethered tactile interfaces for an on-skin telehaptic system

For highly immersive telehaptic applications, skin-integrated, untethered, and highly pixelated transducer devices that can record and generate tactile stimuli are required. Here, we propose a skin-conformable tactile sensor and actuator array with high spatial resolution of 1.8 mm for realising untethered tactile communication on human skin. The tactile sensors are designed to exhibit ultra-flexibility and bimodal sensitivity to static and dynamic pressure. The actuators are miniaturised to sub-millimetre scale to provide sophisticated, high spatiotemporal resolution tactile feedback over a centimetre square area of the fingertip with the capacity to generate vibrotactile feedback under an external load of up to 529 kPa. Short time Fourier transform analysis showed that our telehaptic system can transmit various types of tactile stimuli, such as the shape of objects and letters, textures of fabrics, and vibration patterns with high fidelity.

Evidence for the Effectiveness of Feedback from Wearable Inertial Sensors during Work-Related Activities: A Scoping Review

Background: Wearable inertial sensor technology (WIST) systems provide feedback, aiming to modify aberrant postures and movements. The literature on the effects of feedback from WIST during work or work-related activities has not been previously summarised. This review examines the effectiveness of feedback on upper body kinematics during work or work-related activities, along with the wearability and a quantification of the kinematics of the related device. Methods: The Cinahl, Cochrane, Embase, Medline, Scopus, Sportdiscus and Google Scholar databases were searched, including reports from January 2005 to July 2021. The included studies were summarised descriptively and the evidence was assessed. Results: Fourteen included studies demonstrated a ‘limited’ level of evidence supporting posture and/or movement behaviour improvements using WIST feedback, with no improvements in pain. One study assessed wearability and another two investigated comfort. Studies used tri-axial accelerometers or IMU integration (n = 5 studies). Visual and/or vibrotactile feedback was mostly used. Most studies had a risk of bias, lacked detail for methodological reproducibility and displayed inconsistent reporting of sensor technology, with validation provided only in one study. Thus, we have proposed a minimum ‘Technology and Design Checklist’ for reporting. Conclusions: Our findings suggest that WIST may improve posture, though not pain; however, the quality of the studies limits the strength of this conclusion. Wearability evaluations are needed for the translation of WIST outcomes. Minimum reporting standards for WIST should be followed to ensure methodological reproducibility.

Haplets: Finger-Worn Wireless and Low-Encumbrance Vibrotactile Haptic Feedback for Virtual and Augmented Reality

We introduce Haplets, a wearable, low-encumbrance, finger-worn, wireless haptic device that provides vibrotactile feedback for hand tracking applications in virtual and augmented reality. Haplets are small enough to fit on the back of the fingers and fingernails while leaving the fingertips free for interacting with real-world objects. Through robust physically-simulated hands and low-latency wireless communication, Haplets can render haptic feedback in the form of impacts and textures, and supplements the experience with pseudo-haptic illusions. When used in conjunction with handheld tools, such as a pen, Haplets provide haptic feedback for otherwise passive tools in virtual reality, such as for emulating friction and pressure-sensitivity. We present the design and engineering for the hardware for Haplets, as well as the software framework for haptic rendering. As an example use case, we present a user study in which Haplets are used to improve the line width accuracy of a pressure-sensitive pen in a virtual reality drawing task. We also demonstrate Haplets used during manipulation of objects and during a painting and sculpting scenario in virtual reality. Haplets, at the very least, can be used as a prototyping platform for haptic feedback in virtual reality.