arXiv subjects

Takeru Hashimoto

Publications and source records attributed to Takeru Hashimoto.

5 recordsLinked to original sources

arXiv2026

MetamorphX: An Ungrounded 3-DoF Moment Display that Changes its Physical Properties through Rotational Impedance Control

Humans can estimate the properties of wielded objects (e.g., inertia and viscosity) using the force applied to the hand. We focused on this mechanism and aimed to represent the properties of wielded objects by dynamically changing the force applied to the hand. We propose MetamorphX, which uses control moment gyroscopes (CMGs) to generate ungrounded, 3-degrees of freedom moment feedback. The high-response moments obtained from CMGs allow the inertia and viscosity of motion to be set to the desired values via impedance control. A technical evaluation indicated that our device can generate a moment with a 60-ms delay. The inertia and viscosity of motion were varied by $0.01\,\mathrm{kg\,m^2}$ and $0.1\,\mathrm{N\,s}$, respectively. Additionally, we demonstrated that our device can dynamically change the inertia and viscosity of motion through virtual reality applications.

cs.HC↗

arXiv2026

Selfrionette: A Fingertip Force-Input Controller for Continuous Full-Body Avatar Manipulation and Diverse Haptic Interactions

We propose Selfrionette, a controller that uses fingertip force input to drive avatar movements in virtual reality (VR). This system enables users to interact with virtual objects and walk in VR using only fingertip force, overcoming physical and spatial constraints. Additionally, by fixing users' fingers, it provides users with counterforces equivalent to the applied force, allowing for diverse and wide dynamic range haptic feedback by adjusting the relationship between force input and virtual movement. To evaluate the effectiveness of the proposed method, this paper focuses on hand interaction as a first step. In User Study 1, we measured usability and embodiment during reaching tasks under Selfrionette, body tracking, and finger tracking conditions. In User Study 2, we investigated whether users could perceive haptic properties such as weight, friction, and compliance under the same conditions as User Study 1. Selfrionette was found to be comparable to body tracking in realism of haptic interaction, enabling embodied avatar experiences even in limited spatial conditions.

cs.HC↗

arXiv2026

Information-Preserving SGS model based on the local inter-scale equilibrium hypothesis

Large eddy simulation has been widely used to simulate turbulence at balanced computational cost and accuracy. Many Subgrid-Scale (SGS) models have been proposed over the years, where data-driven and machine learning-aided approaches set the recent trend. To address the problem of extrapolation in these models, we propose a new data-driven SGS model based on an information-theoretic picture of turbulence. To this end, we estimate the model parameters by maximizing mutual information, which correspond to the scale-by-scale local equilibrium hypothesis in developed turbulence or "information preservation." An a priori test confirmed that the estimated parameters are in good agreement with the previously reported empirical values. Furthermore, a posteriori tests on periodic box turbulence and channel turbulence exhibited accuracy comparable to the existing models. These results suggest the utility of the information-theoretic picture of turbulence for constructing more generic SGS models without the need for empirically prescribed model parameters, while enhancing physical interpretability beyond black-box approaches.

physics.flu-dyn↗

arXiv2025

Perceptual Dimensions of Physical Properties of Handheld Objects Induced by Impedance Changes

Haptics in virtual reality is the emerging dimension after audiovisual experiences. Researchers designed several handheld VR controllers to simulate haptic experiences in virtual reality environments. Some of these devices, equipped to deliver active force, can dynamically alter the timing and intensity of force feedback, potentially offering a wide array of haptic sensations. Past research primarily used a single index to evaluate how users perceive physical property parameters, potentially limiting the assessment to the designer's intended scope and neglecting other potential perceptual experiences. Therefore, this study evaluates not how much but how humans feel a physical property when stimuli are changed. We conducted interviews to investigate how people feel when a haptic device changes motion impedance. We used thematic analysis to abstract the results of the interviews and gain an understanding of how humans attribute force feedback to a phenomenon. We also generated a vocabulary from the themes obtained from the interviews and asked users to evaluate force feedback using the semantic difference method. A factor analysis was used to investigate how changing the basic elements of motion, such as inertia, viscosity, and stiffness of the motion system, affects haptic perception. As a result, we obtained four critical factors: size, viscosity, weight, and flexibility factor, and clarified the correspondence between these factors and the change of impedance.

cs.HC↗

arXiv2024

Bridging Player Intentions: Exploring the Potential of Synchronized Haptic Controllers in Multiplayer Game

In multiplayer cooperative video games, players traditionally use individual controllers, inferring others' actions through on-screen visuals and their own movements. This indirect understanding limits truly collaborative gameplay. Research in Joint Action shows that when manipulating a single object, motor performance improves when two people operate together while sensing each other's movements. Building on this, we developed a controller allowing multiple players to operate simultaneously while sharing haptic sensations. We showcased our system at exhibitions, gathering feedback from over 150 participants on how shared sensory input affects their gaming experience. This approach could transform player interaction, enhance cooperation, and redefine multiplayer gaming experiences.

cs.HC↗