Design and Characterization of a Pneumatic Tunable-Stiffness Bellows Actuator

TL;DR

A self-contained pneumatic actuator that achieves a 1.43× stiffness gain (1332 → 1913 N/m) with no external air source or valves: an air-chamber bellows and a spring bellows are connected and sealed, and compressing the air chamber modulates the stiffness.

Key contributions:

• Analytical models for the volume, pressurized force, and stiffness of a single bellows, composed to predict the stiffness change of the dual-bellows actuator.
• Detailed fabrication process and model verification on the physical prototype.
• A tunable-stiffness building block for robots demanding strength and adaptability — it later became the leg of our HASTA hopping robot.

Learn more

Design and fabrication details are documented on the project page.

BibTeX

@inproceedings{chen2024design,
  title={Design and Characterization of a Pneumatic Tunable-Stiffness Bellows Actuator},
  author={Chen, Rongqian and Kwon, Jun and Chen, Wei-Hsi and Sung, Cynthia},
  booktitle={2024 IEEE 7th International Conference on Soft Robotics (RoboSoft)},
  pages={997--1003},
  year={2024},
  organization={IEEE}
}