30-05-2013, 03:36 PM
Fuzzy logic
ABSTRACT
With the advent of modern computer technology, the field of Artificial
Intelligence is showing a definite utility in all spectrum of life. In the
field of control, there is always a need for optimality with improved
controller performance. In this paper, the feasibility of Fuzzy Logic as
an effective control tool for DC motors is dealt with.
This Fuzzy Logic Controller (FLC) is showing a better performance
than conventional controllers in the form of increased robustness.
In this paper, the role of Fuzzy Logic as a controller and its
implementation is studied.
INTRODUCTION:
Fuzzy logic is a powerful problem solving methodology introduced
by Lotfi Zadeh in 1960’s.
It provides tools for dealing with imprecision due to uncertainty and
vagueness, which is intrinsic to many engineering problems.
It is a superset of Boolean or Crisp logic.
It emerged into mainstream of information technology in late
1980’s and early 1990
FUZZY LOGIC:
Fuzzy logic resembles human decision making with its ability to
work from approximate data and find precise solutions.
Classical logic or Boolean logic has two values or states. Eg. (true
or false). It requires a deep understanding of a system, exact
equations, and precise numeric values.
Fuzzy logic is a continuous form of logic. eg (bad, very bad, poor,
average). It allows modeling complex systems using a higher level
of abstraction originating from our knowledge and experience.
WORKING OF FUZZY LOGIC:
The working of fuzzy logic can be understood by considering a
simplified example of a thermostat controlling a heater fan.
The room temperature detected through a sensor is input to a
controller, which outputs a control force to adjust the heater fan
speed.
The first step in designing such a fuzzy controller is to characterize
the range of values for the input and output variables of the
controller.