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By Courtney Porter Martin
It's
the last day of class, and Pablo Iglesias' students are facing
a test that will determine 30 percent of their grades—the
model helicopter test. Iglesias, 37, teaches Control Systems Design,
a class for engineering students at Johns Hopkins University.
Control systems
are automatic devices that direct a machine to control certain
tasks. Examples of control systems include a plane's autopilot
or a car's cruise control. Thermostats also incorporate control
systems to regulate temperature throughout the day. Iglesias'
students have worked on projects such as designing a control system
that could direct a car to automatically speed up and pass another
vehicle without intervention from the driver.
After five
years of teaching the course using computer simulations, Iglesias
and his TA, Christian Furtmueller, 26, spent a year wiring a computer
program to model helicopters, so students can see if the commands
they've used on the computer actually work. Students work
in small groups for about a month doing the simulations before
they're ready to try it out on the helicopters. The 'copter
is a key teaching tool in a demanding electrical engineering course
aimed at preparing students for high-tech jobs in the aviation
and automotive industries.
Iglesias
initially considered using a model car or plane to demonstrate
control systems, but it was too difficult to connect the car to
a computer, and a plane would work better outside than in a classroom.
The helicopter was fairly easy to connect to a computer, because
it's on a stand.
During the
final class, students input commands on a keyboard. Iglesias tells
each group what he wants their helicopter to do, such as ascend
12 inches and turn 45 degrees in an arc. Students are actually
controlling the speed and angle of the rotor blades.
“I'm
trying to get them to do more hands-on design,” Professor
Iglesias says. “A lot of design courses are very canned exercises.”
The helicopters
themselves are fairly inexpensive, at about $500, and have electric
motors. Add in the computers and the stands, and you're looking
at about $4,000 for the entire set-up. Model helicopters like
these are usually bought by adults who fly them with remote controls.
The
helicopters are about 32 inches long, and the main rotor blade
is 35 inches long. Iglesias purchased six different models from
hobby stores and recently bought a bigger helicopter for $1,700.
His next project is to fly the helicopters without a stand, which
means he'll have to put a computer and sensors inside the
helicopter. The craft will be easier to fly when the weight of
the computer and sensors is proportionally smaller than the helicopter
itself.
The big advantage
to trying out simulations on physical objects is that students
get to experience all the variables that can affect the success
of the control system, such as the vibrations produced when helicopters
fly.
“The
real world always behaves a little differently than
computer simulations,” Furtmueller says. “Whatever you
model isn't always perfect.”
Courtney Porter Martin is an associate editor of Prism.
During the
American Solar Challenge race last summer, students found themselves
yelling at enthusiastic supporters to “Please stand back!”
It wasn't that they lacked an appreciation for their audience.
But if too many people started to crowd around the sleek, aerodynamic
cars, the very energy source that powered them might be blocked.
And for the 30 teams competing for the finish line, every ray
of sunlight mattered.
Sponsored
by the U.S. Department of Energy, the biennial event gives students
and other qualifying teams an opportunity to investigate solar
energy by designing, building, and racing solar-powered vehicles.
“It is one of the best ways to inspire young people to pursue
careers in science and engineering,” says John Horst, spokesperson
for the American Solar Challenge.
Last
summer's ten-day race began on July 15th and followed much
of Route 66 for 2,300 miles from Chicago to Claremont, Calif.
Teams raced from 9 a.m. to 5 p.m. and were required to pull into
14 checkpoints along the route. Some of the top cars averaged
300 miles per day and the winner, the University of Michigan,
made it to Claremont in just over 56 hours.
“It
is a fantastic educational opportunity to learn how to build a
solar car, to be creative, and to push the limits,” says
Nader Shwayhat, Michigan's 2001 team leader. Michigan has
won three of the past six challenges (technically called Sunrayce
before 2001) and the team's success, says Shwayhat, stems
from its professional attitude and its ideal mix of engineering
and business students. “We try to model ourselves after professional
racing teams or corporations. We have a lot of experienced members
who have seen what happens if you don't pay attention to
details.” The Michigan team hopes that this experience will
also pay off at their next stop: the World Solar Challenge, an
1800-mile race stretching across the Australian outback. The race
takes place this month.
To prepare
for the American Solar Challenge, most teams spend the first year
fundraising and designing the one-person cars and the second year
constructing them. Because teams might spend more than $500,000
on the project, they find that marketing the car demands almost
as much effort as building it. “We're on the phone everyday,”
says mechanical engineering student Valerie Sandefur, the 2003
team leader for Iowa State's Team PrISUm. Sandefur says Iowa's
outreach efforts, along with its creative “adopt a solar
cell” program, have paid off with more than 900 people contributing
in the last year. “A lot of the donating companies are excited
to see students who make a commitment and show leadership, students
who understand what real engineering is,” she says. “And
they get the publicity of being associated with alternative energy.”
Support for
the team was also apparent during the 2001 race as “groupies”
followed the Iowa State students for the entire event and alumni
showed up along the road to cheer them on. “It's an
expensive race and it's difficult to logistically organize,
so when we get that kind of support, it's very comforting,”
says Sandefur.
Like most
teams, Iowa State not only brought a solar car to the race, but
it also brought a wide array of support vehicles including a lead
van, a chase van, an advance van to scope out the route, and an
RV full of parents who did all of the cooking and laundry. “The
joke is that it takes more gas to race a solar car than a regular
car,” says Sandefur.
Because solar
vehicle design is still at such an experimental stage, race participants
say the likelihood of having solar cars as a practical means of
transportation is a long way off. But they also believe the concepts
and the technology they're mastering today will be applied
to vehicles using alternative energy sources in the future. For
instance, solar energy might be used in charging stations to re-fuel
electric vehicles.
While winning
is always a consideration, most teams ultimately focus on the
challenge of building an efficient and reliable solar car and
finishing the race in the time allotted. “Finishing is as
good as winning,” says Sandefur. Spokesperson Horst agrees.
“It's the thrill of knowing they've made it through
the race, that they've gone the distance, and they've
moved a car only on the energy of the sun.”
Alice Daniel is a freelance writer based in Fresno, California.
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