arXiv subjects

Easa AliAbbasi

Publications and source records attributed to Easa AliAbbasi.

3 recordsLinked to original sources

arXiv2026

Scene2Hap: Generating Scene-Wide Haptics for VR from Scene Context with Multimodal LLMs

Haptic feedback contributes to immersive virtual reality (VR) experiences. However, designing such feedback at scale for all objects within a VR scene remains time-consuming. We present Scene2Hap, an LLM-centered system that automatically designs object-level vibrotactile feedback for entire VR scenes based on the objects' semantic attributes and physical context. Scene2Hap employs a multimodal large language model to estimate each object's semantics and physical context, including its material properties and vibration behavior, from multimodal information in the VR scene. These estimated attributes are then used to generate or retrieve audio signals, subsequently converted into plausible vibrotactile signals. For more realistic spatial haptic rendering, Scene2Hap estimates vibration propagation and attenuation from vibration sources to neighboring objects, considering the estimated material properties and spatial relationships of virtual objects in the scene. Three user studies confirm that Scene2Hap successfully estimates the vibration-related semantics and physical context of VR scenes and produces realistic vibrotactile signals.

cs.HC↗

arXiv2024

Electro-Mechanical Contact Interactions Between Human Finger and Touchscreen Under Electroadhesion

Electroadhesion (EA) has potential in robotics, automation, space missions, textiles, and tactile displays, but its physics remains underexplored due to limited models and experimental data. This thesis develops an electro-mechanical model to estimate electrostatic forces between human finger and touchscreen under EA and compares it to experimentally measured friction forces. The model aligns well with the data, showing that the electrostatic force changes mainly due to charge leakage from the Stratum Corneum at frequencies below 250 Hz and its electrical properties above 250 Hz. Additionally, a novel approach using electrical impedance measurements estimates electrostatic forces by subtracting skin and touchscreen impedances from the total impedance. This method is the first to experimentally estimate the average air gap between finger and voltage-induced capacitive touchscreen. The effect of electrode polarization impedance, particularly at low frequencies, was also studied, revealing its role in the charge leakage phenomenon. Tactile perception via EA was investigated using DC and AC voltage signals on a touchscreen with 10 participants of varying finger moisture levels. Results showed that AC voltage detection thresholds were significantly lower than for DC, explained by charge leakage at lower frequencies. Participants with moist fingers exhibited higher threshold levels, supported by impedance measurements. The thesis also investigated how touchscreen top coatings influence tactile perception, focusing on EA-free interactions. Psychophysical experiments and physical measurements demonstrated that coating materials significantly affect tactile perception, likely due to molecular interactions. These findings offer insights into finger-touchscreen interactions under EA and have potential applications in designing robotic systems and haptic interfaces using this technology.

cs.HC↗

arXiv2024

Tactile Perception of Electroadhesion: Effect of DC versus AC Stimulation and Finger Moisture

Electroadhesion has emerged as a viable technique for displaying tactile feedback on touch surfaces, particularly capacitive touchscreens found in smartphones and tablets. This involves applying a voltage signal to the conductive layer of the touchscreen to generate tactile sensations on the fingerpads of users. In our investigation, we explore the tactile perception of electroadhesion under DC and AC stimulations. Our tactile perception experiments with 10 participants demonstrate a significantly lower voltage detection threshold for AC signals compared to their DC counterparts. This discrepancy is elucidated by the underlying electro-mechanical interactions between the finger and the voltage-induced touchscreen and considering the response of mechanoreceptors in the fingerpad to electrostatic forces generated by electroadhesion. Additionally, our study highlights the impact of moisture on electroadhesive tactile perception. Participants with moist fingers exhibited markedly higher threshold levels. Our electrical impedance measurements show a substantial reduction in impedance magnitude when sweat is present at the finger-touchscreen interface, indicating increased conductivity. These findings not only contribute to our understanding of tactile perception under electroadhesion but also shed light on the underlying physics. In this regard, the results of this study extend beyond mobile devices to encompass other applications of this technology, including robotics, automation, space missions, and textiles.

cs.HC↗