In nature, some organisms use bioluminescence to communicate. A soft robot developed by a team that includes Harvard University Fellow Stephen Morin and R&D Magazine Scientist of the Year George Whitesides achieves the same glowing effect by pumping chemiluminescent solutions through channels in the robot’s color layer. Image: DARPA
team of researchers led by George Whitesides, the Woodford L. and Ann
A. Flowers University Professor, has already broken new engineering
ground with the development of soft, silicone-based robots inspired by
creatures like starfish and squid.
Now, they’re working to give those robots the ability to disguise themselves.
As demonstrated in an August 16 paper published in Science,
researchers have developed a system—again, inspired by nature—that
allows the soft robots to either camouflage themselves against a
background, or to make bold color displays. Such a “dynamic coloration”
system could one day have a host of uses, ranging from helping doctors
plan complex surgeries to acting as a visual marker to help search crews
following a disaster, said Stephen Morin, a Post-Doctoral Fellow in
Chemistry and Chemical Biology and first author of the paper.
we began working on soft robots, we were inspired by soft organisms,
including octopi and squid,” Morin said. “One of the fascinating
characteristics of these animals is their ability to control their
appearance, and that inspired us to take this idea further and explore
dynamic coloration. I think the important thing we’ve shown in this
paper is that even when using simple systems—in this case we have
simple, open-ended micro-channels—you can achieve a great deal in terms
of your ability to camouflage an object, or to display where an object
of the most interesting questions in science is ‘Why do animals have
the shape, and color, and capabilities that they do?'” said Whitesides.
“Evolution might lead to a particular form, but why? One function of our
work on robotics is to give us, and others interested in this kind of
question, systems that we can use to test ideas. Here the question might
be: ‘How does a small crawling organism most efficiently disguise (or
advertise) itself in leaves?’ These robots are test-beds for ideas about
form and color and movement.”
The microfluidic networks used for camouflage or display are contained in thin silicone sheets referred to as color layers. Various heated or cooled dye, chemiluminescent and fluorescent solutions and water can be pumped through the color layers to adjust temperature and appearance. Image: DARPA
as with the soft robots, the “color layers” used in the camouflage
start as molds created using 3D printers. Silicone is then poured into
the molds to create micro-channels, which are topped with another layer
of silicone. The layers can be created as a separate sheet that sits
atop the soft robots, or incorporated directly into their structure.
Once created, researchers can pump colored liquids into the channels,
causing the robot to mimic the colors and patterns of its environment.
The system’s camouflage capabilities aren’t limited to visible colors though.
pumping heated or cooled liquids into the channels, researchers can
camouflage the robots thermally (infrared color). Other tests described
in the Science paper used fluorescent liquids that allowed the color
layers to literally glow in the dark.
The uses for the color-layer technology, however, don’t end at camouflage.
as animals use color change to communicate, Morin envisions robots
using the system as a way to signal their position, both to other
robots, and to the public. As an example, he cited the possible use of
the soft machines during search and rescue operations following a
disaster. In dimly lit conditions, he said, a robot that stands out from
its surroundings (or even glows in the dark) could be useful in leading
rescue crews trying to locate survivors.
we hope is that this work can inspire other researchers to think about
these problems and approach them from different angles,” he continued.
“There are many biologists who are studying animal behavior as it
relates to camouflage, and they use different models to do that. We
think something like this might enable them to explore new questions,
and that will be valuable.”
Camouflage and Display for Soft Machines
Source: Harvard University