A SQUELCHY blob, the octobot doesn’t bear any resemblance to the Terminator-style robots of popular imagination, yet it heralds a revolution in robotics.

Created by a team from Harvard University, the octobot has no wires, no batteries and was pumped out for peanuts by a 3-D printer.

Yet this is the world’s first entirely autonomous, completely soft robot and is expected to pave the way for a new generation of such machines.

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Like its namesake the octopus, the octobot could, in time, slither its way to places other robots can’t reach and become a vital tool in medical operations or even in rescue missions.

While the potential for soft robots has long been realised, until now engineers have struggled to build entirely compliant models.

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.

“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 Professor Robert Wood of Harvard’s Wyss Institute for Biologically Inspired Engineering. “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.”

WHAT CAN IT DO?

While the octobot signals a massive breakthrough in robotic design, its movement is very limited. It can slowly move its legs up and down but can’t move from the spot.

The key point is that the movement is powered solely by the robot’s own internal pneumatic design.

“Many of the previous embodiments required tethers to external controllers or power sources,” said PhD student Ryan Truby.

“What we’ve tried to do is actually to replace these hardware components entirely and have a completely soft robotic system.”

The silicone gel that forms its body means the octobot is more compatible for use with the human body than robots made from rigid materials.

“Where everybody’s really excited to see soft robots come in is right at the human-robot interface,” said Truby.

“Humans ourselves, we’re very soft… and soft robots are made of materials that are safe for us to interact with.

“Right now he’s kind of flopping back and forth, but it’d be nice to create soft robots that know when they’re interacting with their environment – that have more complicated modes of autonomous functionality.”

HOW DOES IT WORK?

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.

“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, co-first author of the research.

To control the reaction, the team used a microfluidic logic circuit based on pioneering work by co-author and chemist George Whitesides, also from the Wyss Institute. The circuit allows the octobot to shut down the inflation of one set of limbs and begin the inflation of another without any external need for power.

“It’s an analogy of what would be an electrical circuit normally,” said Wood. “Instead of passing electrons around, we’re passing liquids and gases.” The innovation has been welcomed by scientists.

“The combination of the microfluidics with the chemical reaction is really interesting,” said Cecilia Laschi, of the Sant’Anna School of Advanced Studies in Pisa, Italy. “It’s a completely new way to see soft robots.”

WHAT’S NEXT?

The simplicity of the assembly process could lead to 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.”

Professor Jonathan Rossiter of the Bristol Robotics Laboratory said the octobot would be a catalyst for other soft robot designs.

“It’s made in a really nice way. It’s made in a way that other people can look at and say, we could use these technologies ourselves – we can make ones that have better fuel systems, or have better control systems, or a more sophisticated body,” he said. “This is a good demonstration of bringing everything together. That’s not easy, and they’ve done a good job.”

Truby pointed out that 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,” he said.

Experts are already looking at how the design can be developed.

“Now what needs to be worked out is how to reprogram the robots to perform different actions, to respond to the environment, and not just perform a pre-programmed sequence,” says materials engineer Robert Shepherd of New York’s Cornell University.