This paper reports on a thermal illusion called thermal masking. Thermal masking is a phenomenon induced by thermal referral to completely mask the original thermal sensation, providing thermal sensation only at the tactile site. Three experiments are conducted using thermal and vibrotactile actuators to investigate the nature of thermal masking on human arms. The first experiment investigates the effects of different temperatures on masking. The results show a higher percentage of thermal masking occurs in warm than hot or cold conditions. The second experiment examines how far the thermal masking can be perceived. The results show that masking can reach up to 24 cm from the thermal site. The third experiment explores the interaction space by placing the tactile actuators on the opposite side of the thermal actuator. The results confirm that thermal masking can reach the other side of the arm, and the performance was higher in warm conditions.
doi.org/10.1145/3613904.3641941
Feeling haptics with our fingerpads is how we achieve manual tasks (e.g., operate a needle or press buttons). Following this, research started adding actuators atop the users’ fingerpads to render haptic feedback for interactive virtual environments. Recently, many have moved away from thick actuators (e.g., vibration motors) and turned to electrode-films with electrotactile stimulation—allowing users to still feel some sensations through the devices when touching physical objects (e.g., compliance or some macro features). However, we argue & demonstrate that thin devices are not enough to maximize the user’s dexterity. We evaluate how adding small holes to electrotactile films can allow direct contact and thus increase haptic permeability, resulting in: (1) improved perception of tactile features; and (2) improved force control in grasping tasks. Finally, we observed participants in interactive experiences and found that holes can preserve dexterity with physical tasks while still benefiting from haptic feedback.
doi.org/10.1145/3613904.3642156
People are increasingly using their smartphones to 3D scan objects and landmarks. On one hand, users have intrinsic motivations to scan well, i.e. keeping the object in-frame while walking around it to achieve coverage. On the other, users can lose interest when filming inanimate objects, and feel rushed and uncertain of their progress when watching their step in public, seeking to avoid attention. We set out to guide users while reducing their stress and increasing engagement, by moving away from the on-screen feedback ubiquitous in existing products and apps meant for 3D scanning. Specifically, our novel interface gives users audio/haptic guidance while they scan statue-type landmarks in public. The interface results from a conceptual design process and a pilot study. Ultimately, we tested 50 users in an ultra-high-traffic area of central London. Compared to regular on-screen feedback, users were more engaged, had unchanged stress levels, and produced better scans.
doi.org/10.1145/3613904.3642271
This study presents ErgoPulse, a system that integrates biomechanical simulation with electrical muscle stimulation (EMS) to provide kinesthetic force feedback to the lower-body in virtual reality (VR). ErgoPulse features two main parts: a biomechanical simulation part that calculates the lower-body joint torques to replicate forces from VR environments, and an EMS part that translates torques into muscle stimulations. In the first experiment, we assessed users' ability to discern haptic force intensity and direction, and observed variations in perceived resolution based on force direction. The second experiment evaluated ErgoPulse's ability to increase haptic force accuracy and user presence in both continuous and impulse force VR game environments. The experimental results showed that ErgoPulse's biomechanical simulation increased the accuracy of force delivery compared to traditional EMS, enhancing the overall user presence. Furthermore, the interviews proposed improvements to the haptic experience by integrating additional stimuli such as temperature, skin stretch, and impact.
doi.org/10.1145/3613904.3642008
Beyond visual and auditory displays, tactile displays and grounded force feedback devices have become more common. Other sensory modalities are also catered to by a broad range of display devices, including temperature, taste, and olfaction. However, one sensory modality remains challenging to represent: kinesthesia – the sense of movement. Inspired by grain-based compliance illusions, we investigate how vibrotactile cues can evoke kinesthetic experiences, even when no movement is performed. We examine the effects of vibrotactile mappings and granularity on the magnitude of perceived motion; distance-based mappings provided the greatest sense of movement. Using an implementation that combines visual feedback and our prototype kinesthetic display, we demonstrate that action-coupled vibrotactile cues are significantly better at conveying an embodied sense of movement than the corresponding visual stimulus, and that combining vibrotactile and visual feedback is best. These results point towards a future where kinesthetic displays will be used in rehabilitation, sports, virtual-reality and beyond.
doi.org/10.1145/3613904.3642499