Integration of soft haptic devices into garments can improve their usability and wearability for daily computing interactions. In this paper, we introduce PneuSleeve, a fabric-based, compact, and highly expressive forearm sleeve which can render a broad range of haptic stimuli including compression, skin stretch, and vibration. The haptic stimuli are generated by controlling pneumatic pressure inside embroidered stretchable tubes. The actuation configuration includes two compression actuators on the proximal and distal forearm, and four uniformly distributed linear actuators around and tangent to the forearm. Further, to ensure a suitable grip force, two soft mutual capacitance sensors are fabricated and integrated into the compression actuators, and a closed-loop force controller is implemented. We physically characterize the static and dynamic behavior of the actuators, as well as the performance of closed-loop control. We quantitatively evaluate the psychophysical characteristics of the six actuators in a set of user studies. Finally, we show the expressiveness of PneuSleeve by evaluating combined haptic stimuli using subjective assessments.
We present Miniature Haptics, a new approach to providing realistic haptic experiences by applying miniaturized haptic feedback to hand-based, embodied avatars. By shrinking haptics to a much smaller scale, Miniature Haptics enables the exploration of new haptic experiences that are not practical to create at the full, human-body scale. Using Finger Walking in Place (FWIP) as an example avatar embodiment and control method, we first explored the feasibility of Miniature Haptics then conducted a human factors study to understand how people map their full-body skeletal model to their hands. To understand the user experience of Miniature Haptic, we developed a miniature football haptic display, and results from our user study show that Miniature Haptics significantly improved the realism and enjoyment of the experience and is preferred by users (p < 0.05). In addition, we present two miniature motion platforms supporting the haptic experiences of: 1) rapidly changing ground height for platform jumping games such as Super Mario Bros and 2) changing terrain slope. Overall, Miniature Haptics makes it possible to explore novel haptic experiences that have not been practical before.
The vibrotactile funneling illusion is the sensation of a single (non-existing) stimulus somewhere in-between the actual stimulus locations. Its occurrence depends upon body location, distance between the actuators, signal synchronization, and intensity. Related work has shown that the funneling illusion may occur on the forehead. We were able to reproduce these findings and explored five further regions to get a more complete picture of the occurrence of the funneling illusion on the head. The results of our study (24 participants) show that the actuator distance, for which the funneling illusion occurs, strongly depends upon the head region. Moreover, we evaluated the centralizing bias (smaller perceived than actual actuator distances) for different head regions, which also showed widely varying characteristics. We computed a detailed heat map of vibrotactile localization accuracies on the head. The results inform the design of future tactile head-mounted displays that aim to support the funneling illusion.
We present a compact broadband linear actuator, Chasm, that renders expressive haptic feedback on wearable and handheld devices. Unlike typical motor-based haptic devices with integrated gearheads, Chasm utilizes a miniature leadscrew coupled to a motor shaft, thereby directly translating the high-speed rotation of the motor to the linear motion of a nut carriage without an additional transmission. Due to this simplicity, Chasm can render low-frequency skin-stretch and high-frequency vibrations, simultaneously and independently. We present the design of the actuator assembly and validate its electromechanical and perceptual performance. We then explore use cases and show design solutions for embedding Chasm in device prototypes. Finally, we report investigations with Chasm in two VR embodiments, i.e., in a headgear band to induce locomotion cues and in a handheld pointer to enhance dynamic manual interactions. Our explorations show wide use for Chasm in enhancing user interactions and experience in virtual and augmented settings.
We present a wearable forearm augmentation that enables the recreation of natural touch sensation by applying shear-forces onto the skin. In contrast to previous approaches, we arrange light-weight and stretchable 3x3cm plasters in a matrix onto the skin. Individual plasters were embedded with lines of shape-memory alloy (SMA) wires to generate shear-forces. Our design is informed by a series of studies investigating the perceptibility of different sizes, spacings, and attachments of plasters on the forearm. Our matrix arrangement enables the perception of touches, for instance, feeling ones wrist being grabbed or the arm being stroked. Users rated the recreated touch sensations as being fairly similar to a real touch (4.1/5). Even without a visual representation, users were able to correctly distinguish them with an overall accuracy of 94.75%. Finally, we explored two use cases showing how AR and VR could be empowered with experiencing recreated touch sensations on the forearm.