Editorial Feature

Invisible Robots – Looking to Nature for Inspiration

The race to explore the most conventional techniques to robot structures is long and competitive. The majority of sophisticated robot structures currently being tested in research are designed and engineered by adapting characteristics of the human body.

A good example of this is ASIMO, the world’s most advanced humanoid robot applied to synchronize with humans, push a cart, and perform simple tasks such as pouring a drink into a cup. Indeed, this is a rather large step forward in exploring how one day our society may integrate more with automated technology to benefit our needs. On a more creative angle, researchers are now beginning to look at the structures to other forms of life (i.e., marine life) and how such life forms could be used as a template to design robotic structures for their application in future rescue and search operations.

It is known that certain marine animals such as the Cephalopod, a member of the molluscan class Cephalopoda (e.g., octopuses, cuttlefish, and squid) have coloured pigments known as chromatophores that look absolutely startling when projected by these animals in the abyssal zone of the ocean. Take a look at the following video. The clip shows a cuttlefish swimming near the Great Barrier Reef in Australia. As the cameraman moves closer to this fish, it immediately shifts its colour display to blend in with its background as a way of protection.

The key function to this colourful display is to camouflage the animal into the background, with this being the main attraction to researchers aiming to engineer robots that carry the same characteristic.

Research

Researchers at Harvard University have attracted a flurry of media attention for designing a robot inspired by camouflage capabilities of the cephalopod – a study that was published in Science 2012 titled: ‘Camouflage and Display for Soft Machines’. Stephen Morin and a team of researchers explored the use of microfluidic networks to introduce changes in the colour, contrast, and surface temperature of soft polymer robotic systems (see an introductory video on this ground-breaking research).

So How Can Soft Polymer Systems Move and Change Colour to Camouflage into their Surrounding Environment?

It appears that a soft lithiography method can be applied to colour the transparent structure to a soft robot. The same Harvard University research team published a paper in the Proceedings of the National Academy of Sciences that helps explain the design and engineering of a camouflage robot. The robot designed by this team has no sensors and so you’re probably wondering how this system can communicate with its surrounding environment, right? This soft robot functions purely on five actuators and a valving system. The robot navigates its way through difficult obstacles by a adopting a crawling technique.

Pneumatic networks have been incorporated into the design of the camouflage robot. Pneumatic structures will affect the mechanical motion of a system upon applying pressurized gas. Designing a robot with a pneumatic network makes the system economical and simple to control. To explain the structure in more detail: pneumatic networks encompass a group of chambers within a thin elastomer material. These small pockets react by expanding when exposed to pressurized gas. The two layers of elastomer that sandwich the pocket of gas will carry different levels of strain that forces the soft robot structure to bend.

The robot looks like a jellyfish, with each of the five pneumatic networks performing movement as a result of pressurized gas being fed into these chambers via an external source. Flexible tubes have been used to deliver the gas from a valve to a hub on the robot. Recent evolution of this system has involved incorporating a network of microchip channels that will deliver dye into the silicon-based polymer robot body to help camouflage this structure into its environment (see video below).

One of the main advantages to building camouflage soft robots is so that these systems have the advantage of manipulation, maneuverability, and fabrication in contrast to some of the hard robots that would require large costs during their production phase. The researchers behind this novel camouflage system are interested in looking at how robots designed with this unique skill will be useful for carrying out basic functions in an open environment without causing a major distraction to the inhabitants. Researchers are also interested in how this camouflage ability could be beneficial in surgery and for safety and rescue measures.

References

  • Morin, S.A., Shepherd, R.F., Kwok, A.S, et al. Camouflage and Display for Soft Machines. Science 2012;337:828–832.
  • Shepherd, R.F., Ilievski, F., Choi, W., et al. Multigait soft robot. PNAS 2011;108(51):20400–20403.

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