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Applications abound
for nanocrystalline
diamond coatings
Diamond’s “precious” physical properties
enable the hardest known material
to be a desirable coating for an array
of applications.
“I’m excited about a slew of things,”
said Dr. Patrick J. Heaney, founding
member and chief technology officer
for NCD Technologies LLC, a Madison,
Wis.-based provider of nanoscale polycrystalline,
or nanocrystalline, diamond
(NCD) coatings. “I’m really excited
about coating medical devices.”
Those include implants. Because dia-
SMALLstuff
Nano-quadrotors: robots that fly
Earthquakes collapse buildings, bad guys take hostages,
nuclear power plants melt down. Terrible events happen
every day that put first responders in harm’s way. But what
if there were a safer way to locate trapped survivors, gather
information on radiation and gas leaks, or discreetly identify
the capabilities of criminals without risking the lives of
fire and safety personnel?
Professor Vijay Kumar and his team at the University of
Pennsylvania General Robotics, Automation, Sensing and
Perception (GRASP) Lab have designed devices that do just
that. Their “autonomous agile aerial robots” can maneuver
through doorways and windows, navigate around obstacles
and perform complex aerial acrobatics, all while mapping
their surroundings in real time.
A nano-quadrotor fits in the palm of your hand. It looks
a bit like a pair of popsicle sticks taped into a + shape and
is festooned with microchips, sensors and miniature batteries,
which, according to Kumar, are sometimes secured
with duct tape. “They’re not high tech,” he said. “The frame
consists of carbon fiber rods with a main controller board
attached to the center. We use off-the-shelf components for
most of it. About the only thing high tech is the software we
load onto the chips.”
The software controls the robot’s four independent rotors,
explained Kumar. “Using feedback from on-board
accelerometers and gyros, motor commands are calculated
600 times per second,” enabling the rotors to respond
instantaneously, adjusting pitch, roll and yaw by simply
speeding up or slowing down each motor.
Nano-quadrotors can maintain position relative to their
surroundings, as well as to each other. This allows them to
6 | MAY/JUNE 2012 | MICROmanufacturing
NCD Technologies
Tools coated with nanocrystalline diamond.
mond is biocompatible, it could be deposited
as a coating on various implanted
metals that often cause health problems
in patients sensitive to metals, such
as cobalt, chromium and nickel. Heaney
added that diamond has beneficial antibacterial
properties, making it difficult
for bacteria to grow on it.
Because it is so hard, diamond is
highly wear-resistant. Compared to conventional
metal and polymer implants,
artificial joints coated with nanocrystalline
diamond would offer a marked
reduction in wear debris and should
prevent inflammation and toxicity that
results when the body’s immune system
attacks the debris caused by wear,
GRASP Lab
Nano-quadrotors flying in formation.
fly like a flock of birds—or other creatures. “We studied the
insect and animal worlds and were able to mimic the capabilities
of, for example, a group of ants,” said Kumar. “The
robots monitor the separation between each other as they
fly and maintain an equal distance, avoiding collisions and
coordinating movement across the group.”
And, by working together, they can lift items much heavier
than any individual robot.
But one of the robot’s main virtues—its size—is also
one of its disadvantages. “The smallest ones have a battery
life of about 10 minutes, depending on their payload,” said
Kumar. “Quadrotors are not particularly efficient.” To get
around this problem, Kumar and his team have deployed
teams of robots on motherships to the work site, allowing
them to conserve energy for the primary mission. “We’ve
also developed automated charging capabilities. The robots
know when they’re running out of juice, and they go
find a charging station.”
—Kip Hanson
Videos of the nano-quadrotors in flight can be found at www.
micromanufacturing.com.—Ed