IEEE Spectrum August, 2010 - 10

Sonar navigation
system

One of seven
thrusters

Syntactic foam
flotation block
HD video
cameras
and LED
floodlights
Robotic
manipulator
arms

seafloor Workhorse: Work-class rOVs are designed to do power-intensive work
hundreds of meters below the surface. photo: schillinG robotics

of the robots at the spill site in the
Gulf. Despite the BP disaster, analysts
expect deep-water oil production
worldwide to rise from 6 million to
10 million barrels a day within five
years. And that will drive the total
number of work-class ROVs to 1250
by 2014, according to market analysts
at Douglas-Westwood, in Canterbury,
England. By then work-class ROV
manufacturing and services will be a
US $3.2 billion business, says the firm.
Almost all such ROVs serve oil and
gas companies. (The remainder maintain
subsea telecom cables, aid scientific
research, and mine for diamonds.) Most
offshore operations need just a few robots
for construction and maintenance-
laying cables, operating valves, and
anchoring equipment, among other tasks.
As companies expand operations
with deeper wells and horizontal
drilling, "facilities on the seafloor
will get more and more populated
[with equipment], and more and
more complex operations will have
to be run," says Julio Guerrero, a
mechanical systems and robotics
expert at Schlumberger-Doll
Research Center, in Cambridge,

In early May, after oil in the Gulf of Mexico
began lapping at the Louisiana coast,
James Bellingham of the Monterey
Bay Aquarium Research Institute, in
California, sent a flurry of e-mails to
colleagues, asking if they could deploy

Na * IEEE spEctrum * august 2010

150-kilowatt
hydraulic
power unit
Cargo space for
instruments and tools

Gliders in the Gulf

10

Fiber-optic video
transport and
control system

Mass. "That is what will require
development of more sophisticated
technology," Guerrero says.
This includes more sophisticated
robots. "ROVs will be called on to
do more varied tasks and a greater
proportion of them," Schilling
says. They will likely work in larger
numbers and in closer proximity,
not unlike the congested operation
unfolding around BP's blownout well in the Gulf of Mexico.
And with so many ROVs working
in such close quarters, mishaps are
more likely. In early June, two ROVs
collided, dislodging a tube inserted
into a riser pipe. Later that month,
an ROV likely nudged a valve shut
on the containment cap that was
siphoning oil to the surface. The
cap had to be removed for a day and
repaired. "There are an unbelievable
number of ROVs operating down
there," retired Coast Guard Admiral
Thad Allen told reporters after the
incident. Two setbacks in two months
of work "is a pretty good record."
But some ROV experts think this
record could be improved. The solution
probably won't involve engineering

"gliders" to track the spread of the
slick. By the fifth week of the disaster,
the autonomous, torpedo-shaped
submersibles started showing up, sent
by Rutgers University, iRobot, and others.
The robotic technology, just a decade old,
was ready to take on a new challenge.
The gliders move by repeatedly

changing their buoyancies, collecting
data from the ocean while undulating
through it [see "Yellow Submarine,"
IEEE Spectrum, March 2010]. Little by
little, they're building a picture of what's
happening to the oil-where the currents
are carrying it, and how the chemical
dispersants applied at the spill site are

spectrum.ieee.org

yanwU ZhanG/Mbari

work, they sent ROVs to saw off the
busted pipe, position a four-story dome
over the well, and later install a smaller
oil-collecting cap in its place. "In those
kinds of water depths, nothing happens
without an ROV," Schilling says.
Sending human divers below
200 meters is risky and expensive.
BP's gusher sits at 1500 meters-easily
reachable by ROVs, which can work at
depths as great as 7000 meters when
equipped with blocks of syntactic
foam. The blocks, made of epoxy and
glass microspheres, compose much of
the robot's bulk and keep it buoyant.
A "work-class" ROV requires a lot
of power to drive its hydraulic pumps,
which spin thrusters and animate
manipulator arms and tools, allowing the
robot to haul half a metric ton. Electricity,
at as many as 3600 volts, flows from
a generator on board a surface ship to
the ROV through its massive tether.
Unwieldy and cumbersome beasts,
tethers stretch as far as 8 kilometers and
weigh up to 15 metric tons, about three
times the weight of the ROV itself. "Most
of the energy in piloting an ROV goes
into moving the cable through the water,"
says Craig Dawe, chief ROV pilot at
the Monterey Bay Aquarium Research
Institute (MBARI), in California.
Work-class robots make up less than
a third of the world's ROVs, but they are
the industry's fastest growing sector.
Since shortly after the Arab oil embargo
in 1973, the global work-class ROV
fleet has grown from just three to more
than 700. Texas-based Oceaneering
International dominates the market
with 253 ROVs and is supplying most
http://spectrum.ieee.org
Table of Contents for the Digital Edition of IEEE Spectrum August, 2010
