ElaStick: A Handheld Variable Stiffness Display for Rendering Dynamic Haptic Response of Flexible Object

Haptic controllers have an important role in providing rich and immersive Virtual Reality (VR) experiences. While previous works have succeeded in creating handheld devices that simulate dynamic properties of rigid objects, such as weight, shape, and movement, recreating the behavior of flexible objects with different stiffness using ungrounded controllers remains an open challenge. In this paper we present ElaStick, a variable-stiffness controller that simulates the dynamic response resulting from shaking or swinging flexible virtual objects. This is achieved by dynamically changing the stiffness of four custom elastic tendons along a joint that effectively increase and reduce the overall stiffness of a perceived object in 2-DoF. We show that with the proposed mechanism, we can render stiffness with high precision and granularity in a continuous range between 10.8 and 71.5Nmm/degree. We estimate the threshold of the human perception of stiffness with a just-noticeable difference (JND) study and investigate the levels of immersion, realism, and enjoyment using a VR application.

@inproceedings{10.1145/3379337.3415862,
author = {Ryu, Neung and Lee, Woojin and Kim, Myung Jin and Bianchi, Andrea},
title = {ElaStick: A Handheld Variable Stiffness Display for Rendering Dynamic Haptic Response of Flexible Object},
year = {2020},
isbn = {9781450375146},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/3379337.3415862},
doi = {10.1145/3379337.3415862},
booktitle = {Proceedings of the 33rd Annual ACM Symposium on User Interface Software and Technology},
pages = {1035–1045},
numpages = {11},
keywords = {controller, dynamic force response, haptics, stiffness, virtual reality},
location = {Virtual Event, USA},
series = {UIST '20}
}

Additional Publication

Neung Ryu, Myung Jin Kim, and Andrea Bianchi. 2020. Demonstration of ElaStick: A Variable Stiffness Display for Rendering Handheld Flexible Object. In SIGGRAPH Asia 2020 Emerging Technologies (SA '20). Association for Computing Machinery, New York, NY, USA, Article 5, 1–2. https://doi.org/10.1145/3415255.3422894