and ROBOTS

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www.servomagazine.com/index.php?/magazine/article/december2010_GeerHead
The researchers manufacture the nanofabric in a
manner similar to the process of producing wood-based
paper. Because the material can separate many other types
of elements and compounds from water, users can apply it
to many types of water clean-up scenarios.
Light It Up
The environment’s powerful new robot ally rids oil by
one of three methods, actually still under development. The
most likely method is simply burning it off as the fabric
passes through a heat chamber in the head of the robot.
Researchers construct the fabric with potassium manganese
oxide-based nanowires that easily survive temperatures
above oil’s boiling point. The oil evaporates quickly as a
result, according to Adam Pruden, a seaswarm
representative. With the burning method, the material
could stay in the water in continual use for weeks at a time.
Alternate oil processing methods under consideration
include digestion by microorganisms or squeezing the oil
out of the nanofabric and bagging it for later retrieval.
Researchers power the seaswarm robots using solar
cells on top of the head of the robot. Solar panels two
meters by two meters covering each robotic head could
supply the 300W of power necessary to run the bot. With
this amount of power, the robot could do all its processing
and move through the water at a rate of 10 kilometers
per hour.
The robot could even store surplus energy in its
onboard batteries so the robot could continue to move and
process oil throughout the dark hours of the night. As solar
cells become more powerful in coming years, researchers
could make the seaswarm power scenario more efficient.
Sensing and Communications
Seaswarm robots work together, and for that they
need a communications modality. The robots are completely
autonomous and use a variety of sensor technologies to
attend to all their duties. The robots count on precise oil
spill location images sent from satellites via Wi-Fi, as well as
their own onboard sensors to locate the oil. They count on
onboard GPS to tell themselves and each other where each
robot is located in relation to the others. The robots sense
their water bound surroundings as a group rather than
individually. In this way, the sensing capabilities of all the
robots combine to tell each robot where to go. The robots
also send images they take using onboard cameras as
streaming video back to the scientists via the web.
The robots intelligence — comprised of very mature
algorithms — works to coordinate the search patterns the
robots use to find the oil. The robots can tell the oil apart
from other matter by sharing sensor data. To do this, the
next seaswarm prototype may use any of the following
sensing options: Garmin USB (GPS), Pontech (embedded
controllers), Seiko PS 050 (servos), fit-PC2 (computer),
Arduino (boards), or MOOS (software).
Clean-Up
In an actual clean-up scenario, the robots would start
at the outer edge of a spill location and move inward until
all the oil is cleaned from that site. They would then move
on to the next spill site and follow the same protocol.
Robot Snakes
GEERHEAD
Robot snakes are particularly significant because of
their form factor and means of locomotion which enable
them to navigate tight spots such as pipes and unusual
surfaces that other robots would stumble over. Places such
as sewers with muck and other substances, as well as trees
or inside vertical pipes are easily scaled by robot snakes.
CMU has been experimenting with five or more snake
robots that have different gaits, purposes, and levels of
development. The scientists achieve the gaits by applying
input to the different joint angles to make them move in a
certain way, to provide locomotion of a certain manner on
a given course. (Think biological gaits.)
Default gaits don’t suit every situation. So, gaits are
fine-tuned or scripted on a case by case basis to address the
difficulty of the area the snakes must scale and the
limitations of the snake such as lack of motor strength for
specific tasks. Tasks requiring special gates include crossing
gaps, reaching or climbing into a hole in a wall, climbing
stairs, crossing railroad tracks, and scanning an area using
Snake robot climbs a tree to get a better look
(extension cord shown).
SERVO 12.2010 11
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