Institute Homepage
Institute Homepage DE Sign In

Back

Article 2018

A Soft, Bistable Valve for Autonomous Control of Soft Actuators

Robotic Materials
Philipp Rothemund
Tenure track professor University of Stuttgart

Almost all pneumatic and hydraulic actuators useful for mesoscale functions rely on hard valves for control. This article describes a soft, elastomeric valve that contains a bistable membrane, which acts as a mechanical “switch” to control air flow. A structural instability—often called “snap-through”—enables rapid transition between two stable states of the membrane. The snap-upward pressure, DP1 (kilopascals), of the membrane differs from the snap-downward pressure, DP2 (kilopascals). The values DP1 andDP2 can be designed by changing the geometry and the material of the membrane. The valve does not require power to remain in either “open” or “closed” states (although switching does require energy), can be designed to be bistable, and can remain in either state without further applied pressure. When integrated in a feedback pneumatic circuit, the valve functions as a pneumatic oscillator (between the pressures DP1 and DP2), generating periodic motion using air from a single source of constant pressure. The valve, as a component of pneumatic circuits, enables (i) a gripper to grasp a ball autonomously and (ii) autonomous earthworm-like locomotion using an air source of constant pressure. These valves are fabricated using straightforward molding and offer a way of integrating simple control and logic functions directly into soft actuators and robots.

Author(s): Philipp Rothemund and Alar Ainla and Lee Belding and Daniel J. Preston and Sarah Kurihara and Zhigang Suo and George M. Whitesides
Journal: Science Robotics
Volume: 3
Number (issue): 16
Pages: eaar7986
Year: 2018
BibTeX Type: Article (article)
DOI: 10.1126/scirobotics.aar7986
Electronic Archiving: grant_archive

BibTeX 

@article{Rothemund18-SCIR-Valve,
  title = {A Soft, Bistable Valve for Autonomous Control of Soft Actuators},
  journal = {Science Robotics},
  abstract = {Almost all pneumatic and hydraulic actuators useful for mesoscale functions rely on hard valves for control. This article describes a soft, elastomeric valve that contains a bistable membrane, which acts as a mechanical “switch” to control air flow. A structural instability—often called “snap-through”—enables rapid transition between two stable states of the membrane. The snap-upward pressure, DP1 (kilopascals), of the membrane differs from the snap-downward pressure, DP2 (kilopascals). The values DP1 andDP2 can be designed by changing the geometry and the material of the membrane. The valve does not require power to remain in either “open” or “closed” states (although switching does require energy), can be designed to be bistable, and can remain in either state without further applied pressure. When integrated in a feedback pneumatic circuit, the valve functions as a pneumatic oscillator (between the pressures DP1 and DP2), generating periodic motion using air from a single source of constant pressure. The valve, as a component of pneumatic circuits, enables (i) a gripper to grasp a ball autonomously and (ii) autonomous earthworm-like locomotion using an air source of constant pressure. These valves are fabricated using straightforward molding and offer a way of integrating simple control and logic functions directly into soft actuators and robots.},
  volume = {3},
  number = {16},
  pages = {eaar7986},
  year = {2018},
  author = {Rothemund, Philipp and Ainla, Alar and Belding, Lee and Preston, Daniel J. and Kurihara, Sarah and Suo, Zhigang and Whitesides, George M.},
  doi = {10.1126/scirobotics.aar7986}
}