If you’ve ever marveled at a flock
of birds moving in complex patterns as if it were one single large organism,
you’re not alone. Researchers at South Dakota School of Mines & Technology
are working to infuse similar cooperative behavior on a collection of flying
robots. This is not an easy task, birds have millions of years of evolution
that allow them to flock, researchers developing swarm robotics are writing mathematical
models to mimic some of this behavior. Developing the ability for drones to
work together in swarms could have wide-ranging applications—from agriculture
to military use. But many scientific hurdles remain.
“These decision-making problems are
very challenging because each independent robot in the swarm has to predict how
others will behave in the future and then make its own decisions accordingly,” says
Shankarachary Ragi, Ph.D., an assistant professor in
the Department of Electrical and Computer Engineering at SD Mines who is leading the
research. Ragi and his team are helping to develop mathematical models, or
algorithms, that enable these kinds of cooperative behaviors in drones.
Decades ago, computer scientists
realized they could build a virtual supercomputer by making several normal-
sized computers work together in a network. Today relatively powerful computing
is available in small packages. Similarly, a collection of drones the size of
hummingbirds programmed to work cooperatively, can multiply their individual capabilities
and act like a single powerful entity. In previous years, robotic swarms were
controlled by a single centralized computer. The holy grail for those working
on swarm technology is to develop algorithms that enable a swarm of drones to
make decisions in a decentralized manner and recover from any mistakes in real
time. “Even if the swarm makes a mistake, something goes wrong, the swarm needs
to learn from this mistake, by immediately reacting and then evolving,” says
Ragi. “Basically, we are developing robust algorithms to account for sudden, unexpected
changes.” It’s a huge challenge; in truth, this process is not easy for living
organisms—after all, birds occasionally fly into windows.
If fully developed, swarm
technology has wide ranging applications. Each individual drone can use its own
on-board sensors (e.g., optical/thermal cameras), to detect and identify
objects of interest--so each drone in a swarm has its own version of part of
the bigger picture. Researchers are also working to build software that allows a
swarm of drones to piece together all images the swarm is seeing and then collectively
identify and differentiate various objects of interest.
Dr. Magesh Rajan, professor and
department head of electrical and computer engineering said, “Our electrical
engineering faculty at SD Mines work at the cutting edge of research in their
fields providing invaluable learning opportunities for students and collaborate
with colleagues across disciplines and around the world to address society's
biggest challenges."
Imagine a new form of organic
precision agriculture where swarms of drones are programmed to recognize and
remove weeds from a field while leaving the crops intact. Or, drones with special
sensors detecting one part of the field that is nutrient deficient, deploying fertilizer
in exactly the right place with the amount needed. Drone swarms could also be
used for building or bridge inspection; detecting tiny changes or stress points
in the structure enabling engineers to plan maintenance and repair well before
any problems occur. These swarms also have military and public safety
applications, such as taking down rogue drones. Recently, privately operated
drones flown too close to a runway caused the shutdown of the
United Kingdom’s second largest airport. Swarm technology could someday
be deployed to stop unwanted private drone activity in any area.
Furthermore, the algorithms
developed to help a swarm of drones make decisions and recover from mistakes
can optimize problem solving in other areas. This research could have further
applications in agriculture, medicine, engineering or in any field where
complex problem-solving is needed.