AI – CS364
Fuzzy Logic
Fuzzy Logic Real World Examples
19th October 2006
Dr Bogdan L. Vrusias
b.vrusias@surrey.ac.uk
AI – CS364
Fuzzy Logic
Contents
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Air conditioner (Mitsubishi)
Vacuum cleaner (Panasonic)
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Automatic transmission system (Nissan, Subaru, Mitsubishi)
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Washing machine (Matsushita, Hitachi)
Camcorder (Panasonic, Sanyo, Fisher, Canon)
Other…
Examples taken from the book: Soft Computing and Intelligent
System Design, by F.O. Karray & C. de Silva, 2004.
19th October 2006
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AI – CS364
Fuzzy Logic
Air conditioner (Mitsubishi)
• Conventional air conditioning systems use on-off controllers. When
the temperature drops below a preset level the unit is automatically
turned off. When the temperature rises above a preset level the unit is
turned on. The former preset value is slightly lower than the latter
preset value, providing a dead zone, so that high-frequency on-off
cycling (chatter) is avoided. The thermostat in the system controls the
on-off action. For example, "when the temperature rises to 25°C, turn
on the unit, and when the temperature falls to 20°C, turn off the unit."
The Mitsubishi air conditioner controls by using fuzzy rules such as:
"If the ambient air is getting warmer, turn the cooling power up a little;
if the air is getting chilly, turn the power down moderately, etc." The
machine becomes smoother as a result. This means less wear and tear
of the air conditioner, more consistent comfortable room temperatures,
and increased efficiency (energy savings).
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Bogdan L. Vrusias © 2006
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AI – CS364
Fuzzy Logic
Vacuum cleaner (Panasonic)
• Characteristics of the floor and the amount of dust are
sensed by an infrared sensor, and the microprocessor
selects the appropriate power by fuzzy control according to
these characteristics. The floor characteristics include the
type (hardwood, cement, tile, carpet softness, carpet
thickness, etc.). The changing pattern of the amount of dust
passing through the infrared sensor is established as well.
The microprocessor establishes the appropriate setting of
the vacuum head and the power of the motor, using a fuzzy
control scheme. Red and green lamps of the vacuum
cleaner show the amount of dust left on the floor.
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Bogdan L. Vrusias © 2006
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AI – CS364
Fuzzy Logic
Automatic transmission system (Nissan, Subaru, Mitsubishi)
• In a conventional automatic transmission system, electronic sensors
measure the vehicle speed and throttle opening, and gears are shifted
based on the predetermined values of these variables. According to
Nissan, this type of system is incapable of uniformly providing
satisfactory control performance to a driver because it provides only
about three different shift patterns. The fuzzy control transmission
senses several variables including vehicle speed and acceleration,
throttle opening, the rate of change of throttle opening, engine load,
and driving style. Each sensed value is given a weight, and a fuzzy
aggregate is calculated to decide whether to shift gears. This controller
is said to be more flexible, smooth, and efficient, providing better
performance. Also, an integrated system developed by Mitsubishi uses
fuzzy logic for active control of the suspension system, four-wheeldrive (traction), steering, and air conditioning.
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AI – CS364
Fuzzy Logic
Washing machine (Matsushita, Hitachi)
• The control system senses both quality and quantity of dirt,
load size, and fabric type, and adjusts the washing cycle
and detergent amount accordingly. Clarity of water in the
washing machine is measured by light sensors. At the start
of the cycle, dirt from clothes will not have yet reached the
water, so light will pass through it easily. The water
becomes more discoloured as the wash cycle proceeds, and
less light will pass through. This information is analyzed
and control decisions are made using fuzzy logic.
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Bogdan L. Vrusias © 2006
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AI – CS364
Fuzzy Logic
Camcorder (Panasonic, Sanyo, Fisher, Canon)
• The video camera determines the best focus and lighting,
particularly when several objects are in the picture. Also, it
has a digital image stabilizer to remove hand jitter. Fuzzy
decision-making is used in these actions. For example, the
following scheme is used for image stabilization. The
present image frame is compared with the previous frame
from memory. A typically stationary object (e.g., house) is
identified and its shift coordinates are computed. This shift
is subtracted from the image to compensate for the hand
jitter. A fuzzy algorithm provides a smooth
control/compensation action.
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Bogdan L. Vrusias © 2006
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AI – CS364
Fuzzy Logic
Other…
• Elevator control (Fujitec, Toshiba): A fuzzy scheme evaluates
passenger traffic and the elevator variables (load, speed, etc.) to
determine car announcement and stopping time. This reduces waiting
time and improves the efficiency and reliability of operation.
• Handheld computer (Sony): A fuzzy logic scheme reads the handwritten input and interprets the characters for data entry.
• Television (Sony): A fuzzy logic scheme uses sensed variables such as
ambient lighting, time of day, and user profile, and adjusts such
parameters as screen brightness, colour, contrast, and sound.
• Antilock braking system (Nissan): The system senses wheel speed,
road conditions, and driving pattern, and the fuzzy ABS determines the
braking action, with skid control.
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Bogdan L. Vrusias © 2006
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AI – CS364
Fuzzy Logic
Other…
• Subway train (Sendai): A fuzzy decision scheme is used by the
subway trains in Sendai, Japan, to determine the speed and stopping
routine. Ride comfort and safety are used as performance
requirements.
• Other applications of fuzzy logic include a hot water heater
(Matsushita), a rice cooker (Hitachi), and a cement kiln (Denmark).
A fuzzy stock-trading program can manage stock portfolios. A fuzzy
golf diagnostic system is able to select the best golf club based on
size, characteristics, and swing of a golfer. A fuzzy mug search
system helps in criminal investigations by analyzing mug shots
(photos of the suspects) along with other input data (say, statements
such as "short, heavy-set, and young-looking . . ." from witnesses) to
determine the most likely criminal. Gift-wrapped chocolates with
fuzzy statements are available for Valentine's Day. Even a Yamaha
"fuzzy" scooter was spotted in Taipei.
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Bogdan L. Vrusias © 2006
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AI – CS364
Fuzzy Logic
Closing
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Questions???
Remarks???
Comments!!!
Evaluation!
19th October 2006
Bogdan L. Vrusias © 2006
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