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USF inventor has trouble digesting robotic rumors


© St. Petersburg Times, published July 31, 2000

TAMPA -- Stuart Wilkinson is not -- and we want to be very clear on this -- not keeping a flesh-eating monster robot in his laboratory at the University of South Florida.

The thing is more choo-choo than Chew Chew, although the latter is its nickname. And it eats sugar cubes, not meat.

That said, it is true that Wilkinson, an associate professor of mechanical engineering, has invented a gastrobot. Actually, he invented the machine and the word. The sign on his office door reads, "Gastrobotics & Gizmology."

And it is also true that Chew Chew, a harmless contraption that looks like a toy train and has never hurt a soul, somehow got identified on the Internet as a dangerous meat eater, a threat to the kids and the dog -- "a toy train with a taste for flesh."

Wilkinson, a member of the USF engineering faculty for 16 years, rolls his eyes and sighs. In the past few days he has taken calls from reporters from all over the globe, he says. France and Chile were among the latest on the line.

"It's wrong to call this a flesh-eating robot," he says. "On the other hand, if the article had not mentioned meat, the story would not have generated the same interest."

A gastrobot, Wilkinson explains, is "an intelligent machine that digests real food for energy." It does this by putting bacteria to work eating carbohydrates, then converting the chemical energy produced into electrical energy.

Imagine a gastrobot in your back yard. You've told it to look after your lawn. It mows, and as it does it picks up the clippings and -- there is no other word for it -- eats them. It pushes them through an opening into its own mechanical stomach, a bacteria repository. The bacteria break down the grass and make electricity, which the gastrobot uses to cut more grass.

This kind of work is going on elsewhere, too.

In England, where the moist soil is inhabited by lots of troublesome slugs, there's a group at the University of West England working on a roving gastrobot, a farmer's friend. A small roving robot gathers a plateful of the chubby little gastropods, carries them to a nearby, centralized "stomach" and tosses them in. Other rovers do the same.

The stomach digests the creatures and converts the chemical energy, in this case methane, into electricity, which it stores. The rovers drive up, plug in to charge up, then scurry off to find more slugs.

If all this sounds a little farfetched, it is. Then again, it isn't.

"At the moment gastrobots can be considered a novelty," Wilkinson readily concedes. "But you can think realistically of things like robotic lawn mowers. There's no reason why it can't be done."

The key, of course, is the device that transforms chemical energy into electricity. It's called an MFC, or microbial fuel cell, and they're not new. Wilkinson credits a man named Peter Bennetto with developing the microbial fuel cell in the 1980s.

"Robotics were not up to the task back then," he says, "but in recent years there has been a lot of progress in the field. We were able to marry the fuel cell with robotics."

In a typical fuel cell, the bacteria produce enzymes that break down carbohydrates. "The molecules in sugar are very large," Wilkinson explains. "When you break them down they release electrons, which are kind of the glue that holds molecules together."

So far so good. But the process does not produce enough electrons to make Chew Chew move. So Wilkinson trickles the electrons into a battery carried on the robot. After 12 to 18 hours of charging, it has enough juice to move Chew Chew slowly ahead for about 15 minutes.

So far, it has moved only once, three months ago.

"It went about to the end of the table it was on, and we turned it off," said Wilkinson. "We were just demonstrating that it would go."

How, then, did this modest little train become a carnivore?

Wilkinson says it began when New Scientist magazine noticed a paper on gastrobotics he had prepared for an upcoming conference in Hawaii. The magazine published a story in July, noting that Chew Chew eats only sugar cubes, but also quoting Wilkinson saying that the ideal fuel, in terms of potential energy, is meat.

"Vegetation is not nearly as nutritious," Wilkinson says in the article.

Reuters noted the New Scientist piece and published an Internet story that began thus: "Man really is in danger of being swallowed up by technology after U.S. scientists announced on Wednesday they had designed a robot that runs on meat."

The word spread, and soon inquiries about the "flesh-eating robot" were pouring in from all over. A variety of Internet sites carried stories based on reports on other Internet sites.

A few, notably the BBC, stayed with the facts, Wilkinson says, but more have been of the "flesh-eating-monster" variety.

Throughout it all, Wilkinson has managed to keep his sense of humor. Only when one story quoted him saying, "Chew Chew prefers to eat flesh," did he call to complain.

"I don't mind people having some fun with this," he said, "but that was going too far."

Now it's back to work. Gastrobots have intriguing potential, but there are many unanswered questions.

Although Chew Chew doesn't produce much in the way of waste -- just carbon dioxide and water -- it would produce more if it ate vegetation or meat.

Wilkinson lightly calls what's left over "robo-poop," but acknowledges that the waste problem is a potential gastrobotic show-stopper. The whole point of a gastrobot is that it would look after itself. Too much maintenance would make the thing pointless.

So, Chew Chew needs a kidney, and Wilkinson says he is working on making one. "I have an idea about that, but I can't discuss it with you now," he says.

After that, maybe a lung to help with respiration.

"Eventually," he says with a smile, "the thing has ended up being us. At that point, why bother?

"Just get a cow."

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