Home' Army Acquisition Logistics and Technology Magazine : Army ALT April-June 2011 Contents The Micro Autonomous Systems and
Alliance (MAST-CTA) of the U.S.
Army Research Laboratory (ARL) is
working to deliver technology to enable
the development of such systems to
team with Soldiers.
"We are trying to enhance tactical
situational awareness in urban and
complex terrain. That is our mission,
and that is the environment we're
working in," said Joseph Mait, Ph.D.,
Senior Technical Researcher for
Electromagnetics at ARL. "Platforms
need to be capable of stable,
robust mobility and air-to-ground
collaboration, and they need to be
able to identify points of ingress."
Mait, who chaired a panel on MAST
Dec. 2 at the 27th Army Science
Conference, emphasized how such
small platforms could provide sub-
stantial capabilities for situational
awareness, including path planning,
threat identification and labeling,
and map generation.
Ronald Fearing, Ph.D., Professor in the
Department of Electrical Engineering
and Computer Sciences at the University
of California, Berkeley, and a member
of the MAST-CTA, discussed several
challenges facing micro-autonomous
systems. Energy management was one
challenge, echoed by panel members.
"It's not just the amount of energy
we have available in a rechargeable
battery or how much we can generate
from a motor, but how we can use that
energy," Fearing said.
Flight, for example, takes a signifi-
cant amount of power. According to
Fearing, battery capacity is the limit-
ing factor, providing a hover time of
about 10 minutes or less on average.
He explained that trade-offs must be
made between climbing and flying
capabilities, and between covering long
distances or operating for long periods.
"What if we make a robot that can
either fly when it needs to fly, or run
or walk when it needs to run or walk?"
Additionally, power for computa-
tion and communication on such a
small scale creates an energy struggle.
Computation costs can be reduced, but
communication energy costs generally
reflect a fixed need for power, Fearing
said. "As a robot gets smaller, the
amount of power we have available for
computation needs to scale," he said.
Another challenge the experts addressed
was lack of a Global Positioning System
signal in operational areas. To address
this problem, "[Robotic] ensembles
must be adaptive ... responsive to
human commands and responsive to
adversarial settings," said Vijay Kumar,
Ph.D., UPS Foundation Professor and
Deputy Dean for Education at the
University of Pennsylvania's School of
Engineering and Applied Science, and
Director of the MAST-CTA Center for
Processing and Autonomous Operation.
The MAST robots must navigate using
cameras or laser range finders and
collaborate as a cohesive unit to map
locations. "Can one operator control a
robot to go through a whole complex?
We think big, but in this case, we want
to deliver small and many," Kumar said.
Actuation was another challenge the
experts discussed. "As motors get small-
er, performance goes down," Fearing
said. "There are always trade-offs
between power density and efficiency
and how fast these things operate."
Robert J. Wood, Ph.D., Assistant
Professor at the Harvard University
School of Engineering and Applied
Sciences, discussed robotic insects
and flight. "We want to use biologi-
cal trends to guide us," he said. As
an example, he cited the Harvard
Microbiotic Fly, which has demonstrat-
ed flapping wings capable of tethered
takeoff, but noted that this develop-
ment also highlights several areas for
future improvement in flight: fabrica-
tion, power, control, and aerodynamics.
Robert Full, Ph.D., Chancellor
Professor and Director of the Poly-
PEDAL (Performance, Energetics,
Dynamics, Animal Locomotion)
Laboratory at the University of
California, Berkeley, reiterated the
importance of biological inspiration.
"We need to look at the organism and
the robot environment as if they were
one," he said. "Nature has a huge num-
ber of sensors. Ultimately, we need
multiple sensors. Robustness is critical.
... Nature can learn, and in the future,
I think we will be able to move to
something far more adaptable."
"Lots of insects have hairs on them
for a variety of reasons---sensing,
navigation, protection," said Kamal
Sarabandi, Ph.D., Rufus S. Teesdale
Professor of Engineering and Director
of the Radiation Laboratory in the
Department of Electrical Engineering
and Computer Science at the Univer-
sity of Michigan, and Director of
the MAST-CTA Center for Microelec-
tronics. "We are developing hair sensors
that can do the same things."
Advantages of Going Smaller
"We're going smaller and gaining some
advantages by having more robots
that are cheaper, disposable, and more
mobile than one large robot," Fearing
said. He posed a disaster situation
involving collapsed rubble, in which a
microrobot would be useful. The tiny
robot could easily navigate through
small spaces to find trapped Soldiers
or civilians, as opposed to a large robot
that would be unable to fit through.
Reduced cost is another great advantage
of microsystems. "They can be made
very inexpensively, without much raw
material in them," Fearing said. "You're
not going to worry as much if you've
got 100 or even 1,000 small robots at
42 APRIL--JUNE 2011
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