Volflex++ is haptic shape-changing interface, capable of altering its size and rigidity simultaneously for presenting characteristics of virtual objects physically. The haptic interface is composed of an array of computer-controlled balloons, with two mechanisms, one for changing size and one for changing rigidity
Currently, shape-changing interfaces do not hold a defined position in the current VR / AR research.
We provide basic knowledge for developing novel types of haptic interfaces that can enhance the haptic perception of virtual objects, allowing rich embodied interactions, and synchronize the virtual and the physical world through computationally-controlled materiality.
The results of this study have been presented at the IEEE VR Conference 2019 in Osaka (JP).
PHSYCOPHYSICAL EXPERIMENT: Haptic Perception of Size and Rigidity
We conducted a study using psychophysics to measure the human tactile perception of these changes. We provide three psychophysical metrics, such as PSE, JND, and WF.
The experiment consisted of two sessions, one dedicated to studying the human haptic perception of changes of rigidity, and a second for the changes of size.
Our results can contribute to the understanding of the perception of variable physical cues oriented to the design of shape-changing interfaces for AR and VR.
Point of Subjective Equality (PSE)
Results of ANOVA: three rigidites / size can be correctly discriminated
The third condition (stiff and large) is the most uniform
Just-Noticeable Difference (JND)
- For Rigidity:
– Complex interplay of sensory informations .
– Force-feedback can influence perception, resulting in large JND .
– Visual stimuli can enhance perception .
– JND increases with the increasing of the reference stimuli .
The WF is larger for small stimuli and small for larger stimuli .
Spherical objects seem to not follow this pattern .
We used contour-following while  used hand’s enclosure, which provides only gross information.
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- Volflex++ has the potential to present a wide variety of sizes and rigidities that are distinguishable by touch.
- Such cues might be perceived by human touch similarly to physical materials with similar characteristics.
- It can be used to represent virtual objects physically, with dynamic size and rigidity.
Alberto Boem, Yuuki Enzaki, Hiroaki Yano, Hiroo Iwata. 2019. Human Perception of a Haptic Shape-changing Interface with Variable Rigidity and Size. In Proceedings of the IEEE Conference on Virtual Reality and 3D User Interfaces, Osaka (JP), 2019. DOI:10.1109/VR.2019.8798214 [pdf]