Prism Magazine - Novmber 2001
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Teaching Tolbox

On Campus - Whirling About in Class

- 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.

On CAmpus - A Race in the Sun

- By Alice Daniel

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.