Table of Contents
PoCoPo is the first handheld pin-based shape display that can render various 2.5D shapes in hand in realtime. We designed the display small enough for a user to hold it in hand and carry it around, thereby enhancing the haptic experiences in a virtual environment. PoCoPo has 18 motor-driven pins on both sides of a cuboid, providing the sensation of skin contact on the user’s palm and fingers. We conducted two user studies to understand the capability of PoCoPo. The first study showed that the participants were generally successful in distinguishing the shapes rendered by PoCoPo with an average success rate of 88.5%. In the second study, we investigated the acceptable visual size of a virtual object when PoCoPo rendered a physical object of a certain size. The result led to a better understanding of the acceptable differences between the perceptions of visual size and haptic size.
Design and Mechanism #
PoCoPo is a modular design. PoCoPo leverages a worm gear mechanism to set the actuators orthogonal to the pins. In this manner, PoCoPo achieves its graspable size by placing the actuators and circuits in a direction that does not interfere with fingers and palm. This mechanism also contributes to the non-backdrivable feature of the pins; thus, avoiding a change of the rendered shape while the user is grasping the device.
PoCoPo can render static objects by controlling each pin length. In addition, by dynamically moving each pin length in the user’s hand, PoCoPo can render movements of VR objects in hand. In the VR application, the user can freely hold animals. As can be seen, the user holding the hedgehog experiences the extrusion of the needles of the hedgehog into their hand by changing pin lengths of PoCoPo. As for the hamster, the user feels the pulse of the hamster, which is represented by the expansion and contraction of the pins of PoCoPo. Meanwhile, if the user holds a snake, he/she feels the wiggle of the snake’s tail.
Antonin Cheymol, Yutaro Hirao, Shigeo Yoshida, and Hideaki Kuzuoka. 2022. Increasing the Perceived Speed of Dynamic Handheld Shape Displays through Visuo-Haptic Illusions. In Augmented Humans 2022 (AHs 2022). Association for Computing Machinery, New York, NY, USA, 218–229. https://doi.org/10.1145/3519391.3519410
Shigeo Yoshida, Yuqian Sun, Hideaki Kuzuoka. 2020. PoCoPo: Handheld Pin-based Shape Display for Haptic Rendering in Virtual Reality. In Proceedings of CHI Conference on Human Factors in Computing Systems Proceedings, Honolulu, HI, USA, April 25–30, 2020 (CHI 2020), 13 pages. https://doi.org/10.1145/3313831.3376358
The paper, presentation slides, and videos in this page can be used under the terms of Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0). https://creativecommons.org/licenses/by-nc-nd/4.0/
We would like to thank Ryunosuke Hirai for developing applications and Yuji Hatada for composing music for the videos of PoCoPo. We thank Taiju Aoki, Naoki Ishida and the members of Cyber Interface Laboratory for their help.