In an old converted textile mill along the banks of the Merrimack River in Manchester, New Hampshire, Dean Kamen thinks he's come up with a device that will eliminate congestion in cities and improve the productivity of city dwellers worldwide. If nothing else, he's certainly invented one of the coolest ways available to cruise around town.
The Segway Human Transport (HT) is a two-wheeled device that resembles a child's scooter on steroids. It was originally conceived as a transportation method for disabled people, but Kamen and his team quickly realized that it held more potential for able-bodied travelers. It balances on two wheels through an intricate system of gyroscopes, processors and sensors that keeps the rider upright, simulating the balancing ability of the human body.
"When you walk, your inner ear is the gyroscope, your inner brain the computer, and your feet the wheels," Kamen says.
One of the overwhelming principles in the design of the HT was this simple credo: "Man Max, Machine Min." Or more simply, when the design teams needed to make a choice between more room for the rider or more room for the machinery, they chose the rider every time, said Scott Waters, industrial design engineer at Segway LLC. This resulted in the HT's small footprint, which takes up no more area than a regular person standing in the same place would.
One of most amazing things about the HT is its ability to remain upright in that small area, even when subjected to stresses and speeds. Five gyroscopes (normally used in fighter jets) made by Silicon Sensing Systems Ltd. work together with two tilt sensors to constantly evaluate the position of the rider's body. The system then compensates for the rider's movements, propelling the HT forward or backward to keep the platform directly underneath the rider's feet.
These systems not only need to perform constantly, but to detect faults in their own performance and decide how to handle them. When you break your ankle, pain tells you to stop walking, so you don't ruin the joint. A machine needs to be able to do the same thing, so it doesn't ruin itself or speed out of control down a long hill.
"We don't only have to deal with failures; we have to assess what failed. We have to build a completely fail-safe device. That's a very difficult challenge," Kamen says.
That's where the "sisterboards" come in. Two processors from Texas Instruments Inc. control the movements of the HT, taking in information from the tilt sensors and gyroscopes and feeding it to the motors. Each sisterboard can operate independently if needed, but they share the workload under normal circumstances. The entire brain of the HT fits into a neat package underneath the rider's feet, about six inches off the ground.
To move forward on the HT, lean forward. To come to a stop or reverse direction, lean back. To turn, twist the handle on the left side of the handlebar. That's it. Even your grandmother could learn to operate it in about five or 10 minutes.
Kamen gives this example: When you take a step forward, you actually lean slightly forward and your brain reminds you to put a foot out in front of your body lest you smack your nose on the pavement. The HT does the same thing, except a gyroscope senses your forward lean, sending that information to the sisterboards, which remind the motor to move the wheels forward lest you smack your nose on the pavement.
After you lean forward and pick up speed, the HT will return to an upright position, regardless of whether you're on a hill or flat ground. If you strike an object, the force of the impact will drive the control shaft back, which will stop the HT in its tracks.
Despite the ease with which an inexperienced rider can jump on the HT and go, Kamen doesn't see his company offering it for sale to consumers for at least another year.
Trials are ongoing with several organizations, such as the U.S. Postal Service, the City of Boston's emergency medical technicians and Amazon.com Inc., and Kamen thinks the business market will keep his company busy for a while.
In fact, he has deviated from his usual practice of licensing his inventions created at his product design company, Deka Research and Development Corp., to outside manufacturers. Segway LLC is the first company he has set up for one of his own inventions, illustrating his desire to keep control over the future direction of the HT and rake in the potential profits.
Kamen loves to talk about the future. He thinks Europe will be an ideal introductory consumer market for the HT, due to the makeup of its cities and citizens. "Europe is way ahead. They are greener, the cities are smaller, there's more mass transit and people are more accustomed to walking. Society in Europe is more likely to embrace the Segway." Asia is the long-term market, he feels, since so many of its cities have yet to be built, and its cities can be designed for the HT.
His eyes brighten as he considers the possibilities: "Clearly, we've moved the technology forward."
Kamen believes the HT has the potential over time to do for urban transportation what the car did for farmers and rural transportation. The car changed what was once an all-day ordeal into town for supplies via horse and buggy to a more manageable trip, freeing time for other pursuits.
"I'd like to think of this as the Model-T -- the technology that changed the world."
It will be years before we know for sure whether Kamen has created a truly revolutionary technology or just another toy for rich people to play with. But if you have a chance to ride one, jump on it. You've never ridden anything like it.
Riding the HT
They don't let you just jump on, but I am shocked when I'm not required to sign a liability waiver. Senior Vice President of Marketing R. Gary Bridge takes me through the basics of the HT in the company's testing lab, holding onto the handlebars as I step onto the riding platform.
He inserts the key, which looks more like a watch battery than a key, which powers up the HT without any audible noises from the motor. The HT has a simple user interface, with a traffic light warning system indicating the running status of the machine, and the image of a smiling human face backlit in green stared up at me as I get my bearings.
I'm fairly tall, at 6'3" (1.9 meters), but the HT's handlebar adjusts to fit just about any conceivable human size. My size-47 feet (U.S. size 12) barely fit on the platform, though, so basketball players might have trouble staying on the platform.
Bridge holds on to the handlebar, and gives me a few brief instructions. The turning mechanism is located on the left handlebar, at the insistence of Dean Kamen, Bridge says. Because an overwhelming majority of the population is right-handed, the left-handed steering mechanism allows riders to keep their right hand free for making adjustments to their cargo, or drawing their gun -- police officers are one of the initial test markets for the HT.
A slight lean forward, and I'm off. The surface is carpeted, and the HT set on low-speed (or "CEO" mode, as it's jokingly called), but Bridge needs to break into a slight jog to keep up with me.
The machine cruises effortlessly, with a quiet whine from the motors only noticeable because most of the lab staff fall silent, watching the maiden voyage of another HT convert. Turning is quick and decisive because the wheels move in opposite directions during a turn.
Stopping is even easier. I had been very skeptical about the stopping power of the HT, a key feature if it is ever to take off in a crowded and bumpy metropolis like Boston. The harder you lean back, the faster it stops, within a few feet in CEO mode.
A few laps around the development lab and I'm ready for some new challenges. Bridge puts the HT on the highest speed setting and right away things are different. The acceleration is quicker and the stopping power matches it. Hard turns require a bit more preparation, bending your knees as you enter the turn.
The HT will not tip over, no matter how fast I am speeding when I violently crank the turning handle. However, if you're not prepared for the turn, it would be possible to lose your balance as it pivots. The HT slows down some when the turning handle is given a hard twist, but a rider who fails to anticipate the turn could be in for some problems, assuming they aren't holding on tightly and have a weak sense of balance.
We take it outside to test it on hills, sidewalks and grass, none of which present a challenge for the HT or its stability. It's rated to travel through water or snow, as long as it doesn't exceed the height of the floor panel and has a range of between 11 to 17 miles (17.6 to 27.2 kilometers), depending on what user mode is set.
My biggest problem with the HT? Keeping still. Every time I try to come to a complete stop and remain in place, I have difficulty keeping the HT from moving slightly back and forth in a rocking motion. I have never been accused of being a tightrope walker, however, and my colleague Scarlet Pruitt had no difficultly with this task.
And if that's my only issue with the HT, I'll just keep riding.
The motors are high-speed electric devices from Pacific Scientific Co. that produce no emissions and put out 2 horsepower. Each wheel is driven independently by its own motor, which can turn the HT quickly and sharply, propelling one wheel forward and the other backward.
Power is supplied to the motors by either nickel cadmium or nickel metal hydride batteries, depending on the requirements of the purchaser. Nickel metal hydride batteries provide higher performance, but nickel cadmium batteries are cheaper. The batteries are recharged simply by plugging any monitor power cord from the base of the steering shaft into a wall outlet. The power unit is able to use either AC or DC outlets.
HT currently uses batteries from Saft Batteries, a subsidiary of Alcatel SA, but the company is "battery agnostic," according to Bridge. Any power sources that meet the HT's requirements will be considered for future versions; the company is currently eyeing lithium ion batteries, which are too expensive for mass use right now, he said. However, don't look for nuclear-powered HTs any time soon.
Michelin North America Inc. makes the HT's tires, which are resilient. Most tires are reinforced on the sides, since when the vehicle turns, the tires will slide on their edges. Since the HT turns so differently from conventional vehicles, its tires never go on edge. Therefore, the strength of the tires needs to be centered on the base, requiring a custom design.
The outer shell of the HT is made from a specially designed plastic from GE Plastics, which is resistant to cracks and breaks. One of the key features of the plastic is the use of NePro, a thin clear film that allows the HT to have a shiny coat resembling paint, but without ruining the ability to recycle its plastic shell. Painting plastic ruins the chance of recycling that material, and is environmentally unfriendly, according to the HT's design engineers.