Please Don't Eat the Daisies

Photo: Sumanee
In cartoons and the sillier side of sci-fi, robots tend to chow down on nuts, bolts, and odd bits of metal, wires, and circuit boards. But in real life, we know, robots don't eat at all. Right? Guess again.

Stuart Wilkinson, an associate professor of mechanical engineering at the University of South Florida at Tampa, has invented a “gastrobot” that does indeed eat—and it doesn't like hardware. This one snacks on sugar, but eventually Wilkinson's machines will dine on vegetation and fruit.

And it's no joke. Wilkinson is part of a movement called “biomimetics.” The idea is, when you have a technical problem to solve, you look to nature for solutions. “You mimic biology,” he says. In this case, there is a problem with how long robots can work outdoors before losing power. Batteries run out, and sockets and long plug wires are too limiting, as are photocells. So the notion was to invent a robot that can forage.

Wilkinson designed the gastrobot to convert consumed food to energy inside its anaerobic “stomach” using a fairly harmless form of the E. coli bacterium. That process creates electrons. Another chemical, HNQ, derived from the henna plant, collects the electrons, delivers them to a fuel cell, then flows back to the robot's guts for more.

Sugar works fine, but cubes of sucrose are rarely found lying around. So a working model will have to be able to graze on whatever vegetation is handy. The problem with feeding the gastrobot plants is, ahem, waste. “We call it robo-poo,” Wilkinson jokes. The difficulty is not creating little piles of robo-poo, it's how to dump the liquid and solid wastes without losing any of the HNQ. Sugar works because the only resulting waste is a tiny amount of carbon dioxide, which is easily emitted. And yes, the robot belches a bit.Photo: USF

Once Wilkinson gets to the bottom of the waste-removal dilemma, he sees all sorts of practical applications. Robots that mow lawns, eat the clippings, and fertilize. Robots that live in gutters and eat their way through dead leaves. Robots that help keep weeds and noxious plants under control.

Meanwhile, the current version is happily lapping up sugar cubes. Made from three wagon-like parts, the gastrobot moves on 12 wheels, and is about three feet long and 18 inches tall. “It looks a bit like a train,” Wilkinson says. Hence its nickname: Chew-Chew.

Some Mighty Big Fries on Mars


CHRISTCHURCH, New Zealand—New Zealanders are every bit as proud of their potatoes as farmers in Idaho, but new research may dampen their spirits somewhat. What's more, the findings could have implications for educators preparing future engineers for inter-planetary exploration.

Michael Mautner is an avid gardener. He's also a chemist in the soil science department at Lincoln University, based near Christchurch on South Island. In a comparison of potatoes and asparagus grown in the fertile agricultural soil of the island's Canterbury region with samples grown in soil taken from Martian meteors, Mautner found that plants grown in phosphate-rich meteor soil were bigger than those reared in New Zealand soil. He presented his findings at a recent astrobiology conference at NASA's Ames Research Center in California.

Photo: SumaneeThe research is important because we may have to turn skyward to feed the world's population as it continues to expand. “One of the resources we'll have to use to grow food will be soils found in various objects in the solar system,” Mautner says.

The lack of availability of water on Mars and its generally cold and unpredictable surface temperatures may make such farming difficult. “To use these soils, we'll have to create an atmosphere and control the temperature with a good deal of planetary engineering,” Mautner says, adding some other parts of the solar system have abundant water.

“In terms of soil resources, we can be more sure now than before that Mars can support all this expansion,” he says. Maybe, but from an earthling's perspective Martian potatoes certainly won't qualify as fast food.

The Combustion Engine's Air Apparent?

JOHANNESBURG, SOUTH AFRICA—The showstopper at the Auto Africa Expo 2000 was neither a powerful sports car nor a sumptuous luxury sedan, but rather a dumpy little van with a top speed of 68 miles per hour. So what's the attraction? It runs on air. Compressed air, that is.

Called the MDI e.volution, the vehicle's tiny 35-kilogram piston engine is powered by 100 kilograms of compressed air from a 30-liter raft of tanks lined up below the body. Emissions are so cool and clean that the Web site for the South African company licensed to manufacture the car, Zero Pollution Motors South Africa, features a video of a man inhaling at the tailpipe. Perhaps more important to potential buyers, the car is supposed to cost less than U.S. 32 cents to drive 100 kilometers (62 miles) in South Africa, where gasoline is expensive and electricity—used to compress the air—is cheap. The MDI e.volution is designed to travel 124 miles at city speeds before it needs to be pumped up again.

Compressed-air engines are hardly new. Many factory tools and even forklifts run on compressed gases. Formula One engine designer Guy Negre was familiar with such motors because they are used to start racing cars. The French engineer built an engine that maximizes efficiency by reheating the decompressing air in stages. He then designed a lightweight van around this 37-kilowatt engine and his company, MDI, licensed it to 21 small manufacturers throughout the world. The French and South African factories plan to be first in commercial production, by 2002 and 2003, respectively.

The extraordinary claims of Negre and Zero Pollution Motors have raised some skepticism within the South African engineering community. Costa Rallis, professor emeritus of thermodynamics and mechanical engineering at the University of the Witwatersrand and a leading designer of unconventional engines, agrees that a breakthrough in the staging of the expansion of air could improve the efficiency of such an engine. But he warns that compressed air has traditionally been “one of the least efficient methods of powering an engine.”
There are working prototype vehicles on the road, but about the only people who have driven them are the investors in MDI. Doubts about the technology's viability can only be addressed when the manufacturers make prototypes available for testing, perhaps later this year.

Hybrid Cars a Hit on the Hill

Representative Baird, Senator Boxer, and the PriusJapan's gasoline-electric hybrid cars have now been available in the U.S. for nearly a year, and they are proving quite popular. According to Toyota, the waiting list for its Prius averages five to six months. The Honda Insight is available from most dealers with little or no waiting. Each of the cars has a high EPA city/highway mileage rate, with the Insight getting 61/68 to the Prius's 45/52. Both models sell best in areas where there are high emission restrictions. California, for example, accounts for 36 percent of all Prius sales. Denver and Chicago are also hot markets.
Even members of Congress are fans of the hybrid car. Rep. Brian Baird (D-WA) owns a Prius, and he believes the car's best feature is the environmental aspect. When at a stop, the Prius doesn't burn energy. Rep. Connie Morella (R-MD) describes the Prius as a “green car with green technology.” Rep. Darrell Issa (R-MD) believes that such luxury cars as Cadillac and Lincoln will eventually embrace the hybrid technology. All three representatives chose the four-door Prius for its roomier interior and back seat; the Insight is a two-door, two passenger hatchback.

Reps. Roscoe Bartlett (R-MD), and Senator Barbara Boxer (D) have also snapped up the Prius, and there might be more Congressional buyers on the way. Baird says that since he has started driving his new car at least a dozen colleagues have asked about it.