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ENG prof: Segway's maxed-out gyro will limit affordability

By David J. Craig

The new Segway Human Transporter is expected to be the most hyped high-tech product since the Apple Macintosh when it becomes available to consumers in about a year. Inventor Dean Kamen and his backers hope the Segway, or "IT" as the mystery invention was commonly referred to before being publicly unveiled this month, will revolutionize short-distance travel. And if you believe the popular press, the device could have an impact on our everyday lives as dramatic as the Internet.

John Baillieul, chairman of the ENG aerospace and mechanical engineering department, says the new Segway scooter will remain very expensive, even if it is mass-produced, because the gyroscope technology it uses was perfected decades ago. Photo by Vernon Doucette

But John Baillieul, chairman of the ENG aerospace and mechanical engineering department, says that the Segway's operating mechanism, which mimics the way the human ear balances the body, relies on gyroscope technology that is anything but revolutionary, and may limit the product's affordability and popularity.

There are two general types of gyroscopes, he says. Conventional mechanical gyroscopes, the type found in the Segway, are used to physically balance objects (think of how the axis of a toy gyroscope wants to keep pointing in the same direction). Newer gyroscopes that rely on MEMS (micro-electro-mechanical system) and fiber-optic technology are used in inertial navigational devices, such as the sensing mechanisms that guide missiles. The MEMS gyroscopes are tiny and move so little that they are virtually indestructible. The fiber-optic gyroscopes, meanwhile, have no moving parts, and therefore, according to Baillieul, are "the world's most perfect machines."

But the mechanical gyroscope was "perfected 25 years ago," Baillieul says. That means the Segway probably will not benefit from rapid technological advances such as those in computing technology that made personal computers so quickly affordable. So when a consumer model becomes available for $3,000 in about a year, don't expect to see it get any cheaper soon afterwards unless competitors produce greatly inferior knock-offs.
"The cost of all the scooter's essential technologies -- the drives, the gears, the electric motor, the batteries, as well as the gyroscope -- have been stable for many years, and they're intrinsically very costly to make," says Baillieul. "They will remain costly even if the scooter achieves widespread acceptance and it's mass-produced. So I don't think you're going to see significant cost reduction over the next 10 years with these scooters."

That's not to say that Baillieul doesn't think the invention is noteworthy. The Segway, which is said to be able to move a 250-pound person and 75 pounds of cargo at up to 17 miles per hour, is much more agile than existing robots, he says, and could be useful for accomplishing specialized tasks, such as carrying military troops and supplies and performing military reconnaissance. "I wouldn't mind getting one or two for my lab," he says. "I'd love to load another robot onto the scooter, instead of a human, and see what it could do carrying some cameras and sensing tools. A lot of the robots used by the military now are quite noisy, but because the Segway is battery-powered, it would be a lot more stealthy. I bet it could go into an urban environment and search out a sniper in a building."

The Segway was developed by DEKA Research, a research and development lab founded by Kamen 20 years ago to create medical devices. The Segway's design is based largely on technology used in the IBOT, a highly mobile wheelchair that DEKA created for Johnson and Johnson in 1999. Both machines use gyroscopes to react to the subtle movements of their human passenger to keep them upright. Segway Company, with financial backing from John Doerr, the venture capitalist behind Netscape and Amazon.com, has built a 77,000-square-foot factory in Manchester, N.H., which will be able to produce 40,000 Segways a month by the end of next year.

At Boston's yearly First Night celebration on December 31, the Boston Police Department will be the first law enforcement body in the country to have officers patrol using an $8,000 industrial-strength version of the Segway scooter. The U.S. Postal Service, the city of Atlanta, and Amazon.com also are among the first wave of institutions to test the scooter.

14 December 2001
Boston University
Office of University Relations