UNIVERSITY OF TECHNOLOGY CONTROL LAB
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وسن شاكر محمود االسم
ميكا -صباحي الشعبة
SEGWAY SYSTEM الموضوع:
30/6/2020 التاربخ:
What is a Segway?
The Segway is a two wheeled, self-balancing electric vehicle invented by Dean
Kamen. It is produced by Segway Inc. of New Hampshire, USA.
Computers and motors in the base of the device keep the Segway upright when
powered on with balancing enabled. Users lean forward to go forward, lean back
to go backward, and turn by using a "Lean Steer" handlebar, leaning it left or
right. Segways are driven by electric servos at up to 20 kilometres per hour.
Gyroscopic sensors are used to detect tilting of the device, which indicates a
departure from perfect balance. Motors driving the wheels are commanded as
needed to bring the Segway back into balance.
A Segway is often used to transport a user across mid range distances in urban
environments. It has more degrees of freedom than car/bike and is faster than
pedestrian. However a navigation system designed for it has not been researched.
The existing navigation systems are adapted for car drivers or pedestrians. Using
such systems on the Segway can increase the driver’s cognitive workload and
generate safety risks
Segway Technology
The dynamics of the Segway are identical to a classic control problem, the
inverted pendulum. The Segway has electric servos powered by Valence
Technology phosphate based lithium-ion batteries which can be charged from
household current. It balances with the help of dual computers running
proprietary software, two tilt sensors, and five gyroscopes (the gyroscopes do not
affect the balance; they are merely used as sensors). The servos rotate the
wheels forwards or backwards as needed for balance or propulsion. The rider
accelerates or decelerates by simply leaning forward or backwards in the direction
he or she wishes to travel. Segway 'gliding' is quick and natural to learn.
The Segway is built to stay balanced in one place. Designed to mirror the process
of human walking, if the rider standing on an initially balanced Segway leans
forward, therefore upsetting the balance, then moves forward to regain balance
just as in walking a leg moves forward to retain balance. With the Segway,
changes from a balanced status are first detected by the gyroscopes, and signals
are passed on to the on board computers, which then direct motors to regain
balance. This process occurs about 100 times per second, so small adjustments to
maintain balance occur almost immediately after the balance is upset by the rider.
The side effect of this balancing system is that as the Segway balances itself the
entire unit changes position in the direction it has moved to restore balance. (For
example, if the rider leans forward, the entire Segway will move forward from its
original position, until the rider restores an upright position on the unit.) This is
precisely how the Segway is controlled — the balancing and movement is
essentially one combined system.
The Segway features a governor (speed limiting) mechanism. When the Segway
approaches the maximum speed allowed by the software, it intentionally begins to
tilt slightly backwards. This moves the platform out in front, and leans the
handlebars backwards towards the rider, eventually nudging the rider to lean back
slightly and slow the Segway down. If not for the governor, riders would be able
to lean farther than the motor could ever compensate for. The Segway also slows
or stops immediately if the handlebar of the unit (or forward bag) nudges into any
obstacle.
Where we can find Segway system in practice ?
1- In 2011 the Segway i2 was being marketed to the emergency
medical services community.
2- The special police forces trained to protect the public during the
2008 summer Olympics used the Segway for mobility.
3- In 2018, the police of Stockholm adopted segways as permanent
transportation method for the patrollers of the old town.
4- The Segway miniPro is also available to be used as the mobility
section of a robot.
What is the main control problem of Segway
system in general?
The two-wheeled inverted pendulum been proposed as a portable
transporter due to its high maneuverability and small footprint. It has
been suggested as a suitable unit for home and uncertain environments
Controlling such a system is a challenging problem due to its
nonlinearities, complex dynamics, and uncertain environmental
conditions. The modeling of the system is also complex because of the
rolling/slipping constraints of the wheels. In spite of its dynamic
complexity, numerous two-wheeled inverted pendulums have been
. created by research institutions and companies
