Robert Wood, the Charles River Professor of Engineering and Applied Sciences, and Jennifer A. Lewis, the Hansjorg Wyss Professor of Biologically Inspired Engineering at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), led the research.
Lewis and Wood are also core faculty members of the Wyss Institute for Biologically Inspired Engineering at Harvard University.
“One longstanding vision for the field of soft robotics has been to create robots that are entirely soft, but the struggle has always been in replacing rigid components like batteries and electronic controls with analogous soft systems and then putting it all together,” said Wood. “This research demonstrates that we can easily manufacture the key components of a simple, entirely soft robot, which lays the foundation for more complex designs.”
It is said that octopuses have long been a source of inspiration in soft robotics. These curious creatures can perform incredible feats of strength and dexterity with no internal skeleton.
Harvard’s octobot is pneumatic-based, and so is powered by gas under pressure. A reaction inside the bot transforms a small amount of liquid fuel (hydrogen peroxide) into a large amount of gas, which flows into the octobot’s arms and inflates them like balloons.
To control the reaction, the team used a microfluidic logic circuit based on the work by co-author and chemist George Whitesides, the Woodford L. and Ann A. Flowers University Professor and a core faculty member of the Wyss. The circuit, a soft analog of a simple electronic oscillator, controls when hydrogen peroxide decomposes to gas in the octobot.
“The entire system is simple to fabricate. By combining three fabrication methods — soft lithography, molding, and 3-D printing — we can quickly manufacture these devices,” said Ryan Truby, a graduate student in the Lewis lab and co-first author of the paper.
The simplicity of the assembly process paves the way for designs of greater complexity. Next, the Harvard team hopes to design an octobot that can crawl, swim, and interact with its environment.
“This research is a proof of concept,” Truby said. “We hope that our approach for creating autonomous soft robots inspires roboticists, material scientists, and researchers focused on advanced manufacturing.”
The paper was co-authored by Daniel Fitzgerald of the Wyss Institute and Bobak Mosadegh of Cornell University. The research was supported by the National Science Foundation through the Materials Research Science and Engineering Center at Harvard and by the Wyss Institute.