CMOS技术在模拟模糊逻辑控制器的设计

Fuzzy Logic was originally developed in the early 1960’s by Professor

Lotfi Zadeh, who claimed for a new kind of computaTIonal paradigm capable

of modeling the own uncertainness of human reasoning. In 1965, Zadeh

published the first ideas on fuzzy sets, the key concept in Fuzzy Logic (FL).

The acceptance of this soft-compuTIng technique by the highly

"determinisTIc" scienTIfic community was not immediate. At the beginning,

the most popular applications of Fuzzy Logic were found in the domain of

Control System. On one hand, many conservative engineers in such area

claim that Fuzzy Control does not convey to better solutions than the

classical ones and that Fuzzy Logic is just a marketing hype. On the other

hand, several non-specialist researchers misinterpret the fact that Fuzzy

Logic deals with uncertainness claiming that ”fuzzy systems reason as

humans do ”, as they use to say. This misunderstanding leads some people to

believe that Fuzzy Logic is a kind of cure-all that can solve any kind of

problem.

Away from any kind of fanaticism however, Fuzzy Logic is a rigorous

mathematical field [Godj97]. Fuzzy reasoning is nothing else than a

straightforward formalism for encoding human knowledge or common sense

in a numerical framework. In a Fuzzy Controller, human experience is

codified by means of linguistic if-then rules that build up a so-called Fuzzy

Inference System, which computes control actions upon given conditions.

Fuzzy Logic has been applied to problems that are either difficult to face

mathematically or applications where the use of Fuzzy Logic provides

improved performance and/or simpler implementations. One of its main

advantages lies in the fact that it offers methods to control non-linear plants,

known difficult to model.

Since the first reported application of Fuzzy Logic [HoOs82], the number

of industrial and commercial developments, covering a wide range of

technological domains, has grown incessantly. Nowadays, countless

researchers from different areas are hardly working on the subject while

contributing with smart and interesting solutions for engineering. Table 1.1,

which summarizes the historical development of Fuzzy Logic, highlights

some of its most significant milestones as reported by [KaLa98].