Introduction: Simple Way To Understand Fuzzy Logic Concept

Before we discuss on application of Fuzzy Logic for control system using Verilog HDL, we will try to understand Fuzzy Logic concept through a simple way, not using mathematical with its complexity. 

What is Fuzzy Logic?
Fuzzy Logic is a methodology to describe operational statement of a system with the expression language (not using mathematics operation).  

Many systems especially very large systems are too complex to be modeled with mathematical equation accurately. Fuzzy Logic uses the expression language approaches to define the operational characteristics of the system, therefore Fuzzy Logic becomes a better & easier solution. The expression language for system characteristics are usually expressed in terms of logical implications: IF – THEN.

History of Fuzzy Logic

History of Fuzzy Logic was started in 1965 where Prof. Lotfi Zadeh (A Professor in Electrical Engineering Faculty, U.C. Berkeley, USA) set the foundation of the "Fuzzy Set Theory and introduced the theory during in seminar paper on "Fuzzy Logic". 

Professor Lotfi Zadeh, the inventor of fuzzy logic, contends that a computer cannot solve problems as well as human experts unless it is able to think in the characteristic manner of a human being. As humans, we often rely on imprecise expressions like "usually", "expensive", or "far". But the comprehension of a computer is limited to a black-white, everything-or-nothing, or true-false mode of thinking. In this context, Lotfi Zadeh emphasizes the fact that we easily let ourselves be dragged along by a desire to attain the highest possible precision without paying attention to the imprecise character of reality [2].

Industrial Applications of Fuzzy Logic
The following is important histories of Fuzzy Logic application in worldwide:

• 1965:  Paper seminar on Fuzzy Logic by Prof. Lotfi Zadeh 
• 1970:  First application of Fuzzy Logic in control engineering (Europe)
• 1975:  Introduction of Fuzzy Logic in Japan
• 1980:  Empirical verification of Fuzzy Logic in Europe
• 1985:  Broad application of Fuzzy Logic in Japan
• 1990:  Broad application of Fuzzy Logic in Europe
• 1995:  Broad application of Fuzzy Logic in the U. S.
• 2000: Fuzzy Logic becomes a standard technology and its also applied in data and sensor signal analysis, business and finance. 

Today, Fuzzy Logic has become a standard technology for control systems, and many electronic device systems have used this technology. 

Eventhough this technology was coming from U. S., Europe is the first in adopting Fuzzy Logic in real application. Japan is the first country in Asia adopted the technology and the first country in the world to implement Fuzzy Logic in broad applications.

Reference:

1. Industrial Application of Fuzzy Logic Control (slide presentations), Inform Software Corporation, 20001  Midwest Rd., Oak Brook, IL 60521, U. S. A.
2. www.fuzzytech.com