Numerous haptic devices have been proposed to support motor learning, such as a hand exoskeleton with mechanical linkages, a vibrotactile glove, and an Electrical Muscle Stimulation (EMS) device. Understanding the impact of each type of feedback on users’ learning performance and experience, as well as the effects of customizing the haptic feedback each user receives, is vital to achieving both efficient and highly motivating learning. To this end, we compared learning performance and experience while using these haptic devices for piano learning. It revealed the distinct characteristics of each device, notably, the exoskeleton was the most preferred despite certain drawbacks. We then conducted a user study to evaluate the effectiveness of haptic customization, allowing participants to customize the order of haptic feedback, demonstrating its advantages such as improved agency and performance. These findings would benefit haptic designers by providing more efficient and optimized haptic feedback for motor learning scenarios.
https://dl.acm.org/doi/10.1145/3706598.3713821
Grain-based compliance illusion mimics the mechanical vibrations when a compliant object deforms with grain-like, short (~15 ms) impulse-response vibrations. Previous work has demonstrated its robust effect on various types of devices. However, the impact of the device's inherent compliance (i.e., base compliance) on perceived compliance remains unclear. This paper investigates the influence of base compliance on the perception of illusory compliance through three psychophysical experiments. The results show that (1) the compliance illusion remained effective with base compliance, (2) the description of compliance was affected by both illusory and base compliance, and (3) it is possible to render the compliance with the same magnitude but multiple different feelings.
Haptic Experience (HX) encompasses distinct quality criteria specific to haptic interactions, yet no standardized instrument exists to measure it. This makes understanding and evaluating HX challenging. This paper reports on the development and validation of the Haptic Experience Inventory (HXI), a questionnaire measuring HX. An item pool of 50 items is developed through theoretical construction, expert reviews (N=10), and cognitive interviews (N=9). These items are then subjected to exploratory and confirmatory factor analysis using data from 591 participants across in-person and online studies, covering vibrotactile, force-feedback, and mid-air devices. Eventually, a 20-item HXI with five dimensions is established: Autotelics, Realism, Involvement, Harmony, and Discord. The HXI converges with theory and shows strong reliability, validity, and measurement invariance, suggesting it is effective across deployed modalities and contexts. The HXI provides empirical evidence about the structure of HX and offers a robust, standardized tool for assessing haptic feedback in research and practice.
https://dl.acm.org/doi/10.1145/3706598.3713834
Providing haptic feedback for soft, deformable objects is challenging, requiring complex mechanical hardware combined with modeling and rendering software. As an alternative, we advance the concept of self-haptics, where the user's own body delivers physical feedback, to convey dynamically varying softness in VR. Skin can exhibit different levels of contact softness by altering the biomechanical state of the body. We propose SkinHaptics, a device-free approach that changes the states of musculoskeletal structures and virtual hand-object representations. In this study, we conduct three experiments to demonstrate SkinHaptics. Using the same scale, we measure skin softness across various hand poses and contact points and evaluate the just noticeable difference in skin softness. We investigate the effect of hand-object representations on self-haptic interactions. Our findings indicate that the visual representations have a significant influence on the embodiment of a self-haptic hand, and the degree of the hand embodiment strongly affects the haptic experience.
Designing haptic effects is a complex, time-consuming process requiring specialized skills and tools. To support haptic design, we introduce HapticGen, a generative model designed to create vibrotactile signals from text inputs. We conducted a formative workshop to identify requirements for an AI-driven haptic model. Given the limited size of existing haptic datasets, we trained HapticGen on a large, labeled dataset of 335k audio samples using an automated audio-to-haptic conversion method. Expert haptic designers then used HapticGen's integrated interface to prompt and rate signals, creating a haptic-specific preference dataset for fine-tuning. We evaluated the fine-tuned HapticGen with 32 users, qualitatively and quantitatively, in an A/B comparison against a baseline text-to-audio model with audio-to-haptic conversion. Results show significant improvements in five haptic experience (e.g., realism) and system usability factors (e.g., future use). Qualitative feedback indicates HapticGen streamlines the ideation process for designers and helps generate diverse, nuanced vibrations.
https://dl.acm.org/doi/10.1145/3706598.3713609
We present a multisensory virtual reality (VR) system that enables users to experience concurrent visual, auditory, and haptic feedback, featuring semantic classification of events from sound, sound-to-haptic conversion, and full-body haptic effects. This concept is applied to enhance the user experience of virtual reality (VR) gameplay. The system utilizes a Long-Short-Term Memory (LSTM) model to classify game sounds and detect key events such as gunfire, explosions, and hits. These events are translated into full-body haptic patterns through a haptic suit, providing users with realistic and immersive haptic experiences. The system operates with low latency, ensuring the seamless synchrony between sound and haptic feedback. Evaluations through user studies demonstrate significant improvements in user experience compared to traditional sound-to-haptic methods, emphasizing the importance of accurate sound classification and well-designed haptic effects.
https://dl.acm.org/doi/10.1145/3706598.3713355
Encounters with virtual agents currently lack the haptic viscerality of human contact. While digital biosignal communication can mediate such virtual social interactions, how artificial haptic biosignals influence users’ personal space during Virtual Reality (VR) experiences is unknown. Designing vibrotactile heartbeats and thermally-actuated body temperature, we ran a within-subjects study (N=31) to investigate feedback (Thermal, Vibration, Thermal+Vibration, None) and agent stories (Negative, Neutral, Positive) on objective and subjective interpersonal distance (IPD), perceived arousal and comfort, presence, and post-experience responses. Findings showed that thermal feedback decreased objective but not subjective IPD, whereas vibrotactile heartbeats (signaling agent's closeness) increased both while heightening arousal and discomfort. Agents' stories did not affect IPD, arousal, or comfort. Our qualitative findings shed light on signal ambiguity and presence constructs within VR-based haptic stimulation. We contribute insights into artificial biosignals and their influence on VR proxemics, with cautionary considerations should the boundaries blur between physical and virtual touch.
https://dl.acm.org/doi/10.1145/3706598.3713231