Fuzzy Logic has played a pivotal part in this age of rapid technological development .In this paper we have elaborated on the automation process used in a washing machine. This paper has focused on the two subsystems of the washing machine namely the sensor mechanism and the controller unit. It also discuss on the use of singletons for fuzzy sets. This paper also highlights the use of a fuzzy controller to give the correct wash time. The use of fuzzy controller has the advantage of managing time, increasing equipment efficiency and diagnosing malfunctions.
Fuzzy logic is used for solving problems with expert systems and real-time systems that must react to an imperfect environment of highly variable, volatile or unpredictable conditions. It "smoothes the edges" so to speak, circumventing abrupt changes in operation that could result from relying on traditional either-or and all-or-nothing logic.
Fuzzy logic was conceived by Lotfi Zadeh, former chairman of the electrical engineering and computer science department at the University of California at Berkeley. In 1964, while contemplating how computers could be programmed for handwriting recognition, Zadeh expanded on traditional set theory by making membership in a set a matter of degree rather than a yes-no situation.
A conventional thermostat works like an ON/OFF switch (fig.2). If we set it at 78F then the heater is activated only when the temperature falls below 75F.When it reaches 81F the heater is turned off .As a result the desired room temperature is either too warm or too hot.
A fuzzy thermostat works in shades of gray where the temperature is treated as a series of overlapping ranges .For example, 78F is 60% warm and 20% hot .The controller is programmed with simple if-then rules that tell the heater fan how fast to run. As a result, when the temperature changes the fan speed will continuously adjust to keep the temperature at desired level. Our first step in designing such a fuzzy controller is to characterize the range of values for the input and output variables of the controller. Then we assign labels such as cool for the temperature and high for the fan speed, and we write a set of simple English-like rules to control the system. Inside the controller all temperature regulating actions will be based on how the current room temperature falls into these ranges and the rules describing the system behavior .The controller’s output will vary continuously to adjust the fan speed.
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