Fuzzy Logic
Definition
Fuzzy logic is an approach to computing based on "degrees of truth" rather than the usual "true or false" (0 or 1) Boolean logic on which the modern computer is based.
Application Area
Aerospace
Altitude control spacecraft
Satellite altitude control
Flow and mixture regulation in aircraft deicing vehicles
Automotive
Trainable fuzzy systems for idle speed control
Improving efficiency of automatic transmissions
Electronics
Air conditioning systems
Washing machine timing
Vacuum cleaners
Finance
Banknote transfer control
Fund management
Stock market predictions
Securities
Decision systems for securities trading
Various security appliances
Architecture
Fuzzification Module
It transforms the system inputs, which are crisp numbers, into fuzzy sets.
Knowledge Base
It stores IF-THEN rules provided by experts.
Inference Engine
It simulates the human reasoning process by making fuzzy inference on the inputs and IF-THEN rules.
It simulates the human reasoning process by making fuzzy inference on the inputs and IF-THEN rules.
Algorithms
Define linguistic variables and terms.
Construct membership functions for them.
Construct knowledge base of rules.
Evaluate rules in the rule base. (Inference Engine)
Combine results from each rule. (Inference Engine)
Advantages
Mathematical concepts within fuzzy reasoning are very simple.
You can modify a FLS by just adding or deleting rules because of its flexibility
Fuzzy logic Systems can take imprecise, distorted, noisy input information.
FLSs are easy to construct and understand.
Fuzzy logic is a solution to complex problems in all fields
Disadvantages
no systematic approach to fuzzy system designing.
understandable only when simple.
only suitable for the problems which do not need high accuracy.
History
Study began since 1920s as infinite valued logic
Fuzzy logic was introduced by Lotfi Zadeh in 1965
A sub way system was built using fuzzy logic in Japan in 1987