Design of Analog Fuzzy Logic Controllers in CMOS Technologies 下载

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].