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Segway Smart MotionTM - The science behind the
technology
When Dean Kamen unveiled the
Segway® Personal Transporter (PT) on ABC's Good Morning
America, he described the machine as "the world's first
self-balancing human transporter." When you look at the
machine in motion, you get an idea of what he's talking
about. Unlike a car, the Segway PT only has two wheels,
yet it manages to stay upright by itself.
To move
forward or backward on the Segway PT, the rider just
leans slightly forward or backward. To turn left or
right, the rider simply moves the LeanSteer frame left
or right.
How
dynamic stabilization works
The ability to
balance on its own is the most amazing thing about the
Segway PT, and it is the key to its operation. To
understand how this system works, it helps to consider
Kamen's model for the device—the human body.
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If you stand up and lean
forward so that you are out of balance, you probably
won't fall on your face. Your brain knows you are out of
balance, because fluid in your inner ear shifts, so it
triggers you to put your leg forward and stop the fall.
If you keep leaning forward, your brain will keep
putting your legs forward to keep you upright. Instead
of falling, you walk forward, one step at a time.
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The Segway PT does pretty
much the same thing, except it has wheels instead of legs, a
motor instead of muscles, a collection of microprocessors
instead of a brain and a set of sophisticated tilt sensors and
gyroscopic sensors instead of an inner-ear balancing system.
Like your brain, the Segway PT knows when you are leaning
forward. To maintain balance, it turns the wheels at just the
right speed, so you move forward. Segway calls this behavior
dynamic stabilization and has patented the unique process that
allows the Segway PT to balance on just two wheels.
The brains and the
brawn
The Segway PT is controlled by an
intelligent network of sensors, mechanical assemblies,
propulsion, and control systems. The second you step on,
five micro-machined gyroscopic sensors and two
accelerometers sense the changing terrain and your body
position at 100 times per second – faster than the brain
can think.
Segway PTs use a special solid-state
angular rate sensor constructed using silicon. This type
of gyroscopic sensor determines an object's rotation
using the Coriolis effect on a very small scale.
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Simply
put, the Coriolis effect is the apparent turning of a moving
object in relation to another rotating object. For example, an
airplane trying to travel in a straight line can appear to
turn because the Earth is rotating underneath it.
The
Segway PT has five gyroscopic sensors, though it only needs
three to detect leaning forward or backward (termed "pitch"),
leaning to the left or right (termed "roll") and steering to
the left or right (termed "yaw"). The extra sensors add
redundancy, to make the product more reliable. All of this
leaning and steering information, as well as information from
additional tilt sensors, is passed on to the brain of the
device.
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The brains and brawn are made
up of two identical and redundant sets of
microprocessor-based electronic controller circuit
boards, batteries and motor windings that operate
together and share the load of driving the wheels. The
Segway PT has a number of additional onboard
microprocessors. The vehicle requires this much brain
power because it needs to quickly make precise
adjustments to keep from falling over. If one controller
board (or it’s associated battery, motor windings or
wiring) breaks down, the other set will take over all
functions so that the system can notify the rider of a
failure and shut down
gracefully.
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The
microprocessors run an advanced piece of software that
controls the Segway PT. This program monitors all of the
stability information coming from the gyroscopic sensors and
adjusts the speed of the electric motors in response to this
information. The electric motors, which are powered by a pair
of rechargeable lithium-ion batteries, can turn each of the
wheels independently at variable speeds.
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motors drive both wheels forward to keep the PT from
tilting over. When the PT leans backward, the motors
drive both wheels backward. When the rider moves the
LeanSteer frame to turn left or right, the motors drive
one wheel faster than the other, or if traveling slowly
enough, drive the wheels in opposite directions, so that
the Segway PT rotates (steers). When under way, the
Segway PT will generate precisely the right radius of
turn so that your lean is balanced by the centripetal
acceleration generated by the turn. |
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 Contact Form
FAQ
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Future Concepts Ltd. 25/7 Cuu Long Street, Ward
2, Tan Binh District, Ho Chi Minh City, Vietnam
info@segway.com.vn
- Telephone: +84 (0)8 88487816, Fax: +84 (0)8 8446007
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