Beyond a simple notification of incoming calls or messages, more complex information such as alphabets and digits can be delivered through spatiotemporal tactile patterns (STPs) on a wrist-worn tactile display (WTD) with multiple tactors. However, owing to the limited skin area and spatial acuity of the wrist, frequent confusions occur between closely located tactors, resulting in a low recognition accuracy. Furthermore, the accuracies reported in previous studies have mostly been measured for a specific posture and could further decrease with free arm postures in real life. Herein, we present Heterogeneous Stroke, a design concept for improving the recognition accuracy of STPs on a WTD. By assigning unique vibrotactile stimuli to each tactor, the confusion between tactors can be reduced. Through our implementation of Heterogeneous Stroke, the alphanumeric characters could be delivered with high accuracy (93.8% for 26 alphabets and 92.4% for 10 digits) across different arm postures.
We propose a new type of haptic actuator, which we call MagnetIO, that is comprised of two parts: one battery-powered voice-coil worn on the user’s fingernail and any number of interactive soft patches that can be attached onto any surface (everyday objects, user’s body, appliances, etc.). When the user’s finger wearing our voice-coil contacts any of the interactive patches it detects its magnetic signature via magnetometer and vibrates the patch, adding haptic feedback to otherwise input-only interactions. To allow these passive patches to vibrate, we make them from silicone with regions doped with polarized neodymium powder, resulting in soft and stretchable magnets. This stretchable form-factor allows them to be wrapped to the user’s body or everyday objects of various shapes. We demonstrate how these add haptic output to many situations, such as adding haptic buttons to the walls of one’s home. In our technical evaluation, we demonstrate that our interactive patches can be excited across a wide range of frequencies (0-500 Hz) and can be tuned to resonate at specific frequencies based on the patch’s geometry. Furthermore, we demonstrate that MagnetIO’s vibration intensity is as powerful as a typical linear resonant actuator (LRA); yet, unlike these rigid actuators, our passive patches operate as springs with multiple modes of vibration, which enables a wider band around its resonant frequency than an equivalent LRA.
We propose ThermoCaress, a haptic device to create a stroking sensation on the forearm using pressure force and present thermal feedback simultaneously. In our method, based on the phenomenon of thermal referral, by overlapping a stroke of pressure force, users feel as if the thermal stimulation moves although the position of temperature source is static. We designed the device to be compact and soft, using microblowers and inflatable pouches for presenting pressure force and water for presenting thermal feedback. Our user study showed that the device succeeded in generating thermal referrals and creating a moving thermal illusion. The results also suggested that cold temperature enhance the pleasantness of stroking. Our findings contribute to expanding the potential of thermal haptic devices.
In ad-hoc human-robot collaboration (HRC), humans and robots work on a task without pre-planning the robot's actions prior to execution; instead, task allocation occurs in real-time. However, prior research has largely focused on task allocations that are pre-planned - there has not been a comprehensive exploration or evaluation of techniques where task allocation is adjusted in real-time. Inspired by HCI research on territoriality and proxemics, we propose a design space of novel task allocation techniques including both explicit techniques, where the user maintains agency, and implicit techniques, where the efficiency of automation can be leveraged. The techniques were implemented and evaluated using a tabletop HRC simulation in VR. A 16-participant study, which presented variations of a collaborative block stacking task, showed that implicit techniques enable efficient task completion and task parallelization, and should be augmented with explicit mechanisms to provide users with fine-grained control.
We propose a technique that allows an unprecedented level of dexterity in electrical muscle stimulation (EMS), i.e., it allows interactive EMS-based devices to flex the user’s fingers independently of each other. EMS is a promising technique for force feedback because of its small form factor when compared to mechanical actuators. However, the current EMS approach to flexing the user’s fingers (i.e., attaching electrodes to the base of the forearm, where finger muscles anchor) is limited by its inability to flex a target finger’s metacarpophalangeal (MCP) joint independently of the other fingers. In other words, current EMS devices cannot flex one finger alone, they always induce unwanted actuation to adjacent fingers. To tackle the lack of dexterity, we propose and validate a new electrode layout that places the electrodes on the back of the hand, where they stimulate the interossei/lumbricals muscles in the palm, which have never received attention with regards to EMS. In our user study, we found that our technique offers four key benefits when compared to existing EMS electrode layouts: our technique (1) flexes all four fingers around the MCP joint more independently; (2) has less unwanted flexion of other joints (such as the proximal interphalangeal joint); (3) is more robust to wrist rotations; and (4) reduces calibration time. Therefore, our EMS technique enables applications for interactive EMS systems that require a level of flexion dexterity not available until now. We demonstrate the improved dexterity with four example applications: three musical instrumental tutorials (piano, drum, and guitar) and a VR application that renders force feedback in individual fingers while manipulating a yo-yo.
Compared to grounded force feedback, providing tactile feedback via a wearable device can free the user and broaden the potential applications of simulated physical interactions. However, neither the limitations nor the full potential of tactile-only feedback have been precisely examined. Here we investigate how the dimensionality of cutaneous fingertip feedback affects user movements and virtual object recognition. We combine a recently invented 6-DOF fingertip device with motion tracking, a head-mounted display, and novel contact-rendering algorithms to enable a user to tactilely explore immersive virtual environments. We evaluate rudimentary 1-DOF, moderate 3-DOF, and complex 6-DOF tactile feedback during shape discrimination and mass discrimination, also comparing to interactions with real objects. Results from 20 naive study participants show that higher-dimensional tactile feedback may indeed allow completion of a wider range of virtual tasks, but that feedback dimensionality surprisingly does not greatly affect the exploratory techniques employed by the user.
Drone assisted navigation aids for supporting walking activities of visually impaired have been established in related work but fine-point object grasping tasks and the object localization in unknown environments still presents an open and complex challenge. We present a drone-based interface that provides fine-grain haptic feedback and thus physically guides them in hand-object localization tasks in unknown surroundings. Our research is built around community groups of blind or visually impaired (BVI) people, which provide in-depth insights during the development process and serve later as study participants. A pilot study infers users' sensibility to applied guiding stimuli forces and the different human-drone tether interfacing possibilities. In a comparative follow-up study, we show that our drone-based approach achieves greater accuracy compared to a current audio-based hand guiding system and delivers overall a more intuitive and relatable fine-point guiding experience.
Today's typical input device is flat, rigid and made of glass. However, advances in sensing technology and interaction design suggest thinking about input on other surface, including soft materials. While touching rigid and soft materials might feel similar, they clearly feel different when pressure is applied to them. Yet, to date, studies only investigated force input on rigid surfaces. We present a first systematic evaluation of the effects of compliance on force input. Results of a visual targeting task for three levels of softness indicate that high force levels appear more demanding for soft surfaces, but that performance is otherwise similar. Performance remained very high (~ for 20 force levels) regardless of the compliance, suggesting force input was underestimated so far. We infer implications for the design of force input on soft surfaces and conclude that interaction models used on rigid surfaces might be used on soft surfaces.
Providing haptic feedback when manipulating virtual objects is an essential part of immersive virtual reality experiences; however, it is challenging to replicate all of an object’s properties and characteristics. We propose the use of visuo-haptic illusions alongside physical proxies to enhance the scope of proxy-based interactions with virtual objects. In this work, we focus on two manipulation techniques, linear translation and stretching across different distances, and investigate how much discrepancy between the physical proxy and the virtual object may be introduced without participants noticing. In a study with 24 participants, we found that manipulation technique and travel distance significantly affect the detection thresholds, and that visuo-haptic illusions impact performance and accuracy. We show that this technique can be used to enable functional proxy objects that act as stand-ins for multiple virtual objects, illustrating the technique through a showcase VR-DJ application.
Different form factors of wearable technology provide unique opportunities for output based on how they are connected to the human body. In this work, we investigate the idea of delivering notifications through devices worn on the underside of a user's clothing. A wearable worn in such a manner is in direct contact with the user's skin. We leverage this proximity to test the performance of 10 on-skin sensations (Press, Poke, Pinch, Heat, Cool, Blow, Suck, Vibrate, Moisture and Brush) as methods of notification delivery. We developed prototypes for each stimulus and conducted a user study to evaluate them across 6 locations commonly covered by upper body clothing. Results indicate significant differences in reaction time, error rates and comfort which may influence the design of future under-clothing wearables.