First soft octopus-like robot runs without batteries, circuits

In a first, Harvard scientists have created a 3D-printed, octopus-like robot that is entirely made of soft components and is powered by chemical reactions instead of rigid batteries and circuit boards.

The robot, nicknamed octobot, could pave the way for a new generation of completely soft, autonomous machines.

Soft robotics could revolutionise how humans interact with machines. However, researchers have struggled to build entirely compliant robots.

Electric power and control systems - such as batteries and circuit boards - are rigid and until now soft-bodied robots have been either tethered to an off-board system or rigged with hard components.

Researchers at Harvard University  in the US with expertise in 3D printing, mechanical engineering and microfluidics developed the first autonomous, untethered, entirely soft robot.

"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," said Robert Wood, professor at Harvard John A Paulson School of Engineering and Applied Sciences (SEAS).

"Through our hybrid assembly approach, we were able to 3D print each of the functional components required within the soft robot body, including the fuel storage, power and actuation, in a rapid manner," said Jennifer A Lewis, from the Wyss Institute for Biologically Inspired Engineering at Harvard.

"The octobot is a simple embodiment designed to demonstrate our integrated design and additive fabrication strategy for embedding autonomous functionality," Lewis said.

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, researchers said.

The octobot is pneumatic-based - 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 a balloon.

"The wonderful thing about hydrogen peroxide is that a simple reaction between the chemical and a catalyst - in this case platinum - allows us to replace rigid power sources," said Michael Wehner, a postdoctoral fellow in the Wood lab.

To control the reaction, the team used a microfluidic logic circuit. The circuit, a soft analogue of a simple electronic oscillator, controls when hydrogen peroxide decomposes to gas in the octobot.

The simplicity of the assembly process paves the way for more complex designs. Researchers hope to create an octobot that can crawl, swim and interact with the environment.

The research appears in the journal Nature.