This Electronics Seminar Topic deals with the following.
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.
- 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 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.
- Labels such as cool for the temperature and high for the fan speed are assigned and a set of simple English-like rules to control the systems are written.
- 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. The temperature controller described above can be defined in four simple rules:
- IF temperature IS cold THEN fan_speed IS high
- IF temperature IS cool THEN fan_speed IS medium
- IF temperature IS warm THEN fan_speed IS low
- IF temperature IS hot THEN fan_speed IS zero .
Fuzzy controller accepts an input value, performs some calculations, and generates an output value. This process is called the Fuzzy Inference Process.
The thermostat works in three steps
- Rule evaluation