AI – CS364 Fuzzy Logic Fuzzy Logic Real World Examples 19 th October 2006 Dr Bogdan L. Vrusias

AI – CS364 Fuzzy Logic 19 th October 2006Bogdan L. Vrusias © Contents Air conditioner (Mitsubishi) Vacuum cleaner (Panasonic) Automatic transmission system (Nissan, Subaru, Mitsubishi) 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.

AI – CS364 Fuzzy Logic 19 th October 2006Bogdan L. Vrusias © 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).

AI – CS364 Fuzzy Logic 19 th October 2006Bogdan L. Vrusias © 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.

AI – CS364 Fuzzy Logic 19 th October 2006Bogdan L. Vrusias © 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-wheel- drive (traction), steering, and air conditioning.

AI – CS364 Fuzzy Logic 19 th October 2006Bogdan L. Vrusias © 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.

AI – CS364 Fuzzy Logic 19 th October 2006Bogdan L. Vrusias © 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.

AI – CS364 Fuzzy Logic 19 th October 2006Bogdan L. Vrusias © 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 hand- written 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.

AI – CS364 Fuzzy Logic 19 th October 2006Bogdan L. Vrusias © 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.

AI – CS364 Fuzzy Logic 19 th October 2006Bogdan L. Vrusias © Closing Questions??? Remarks??? Comments!!! Evaluation!