The English-language thesaurus has the following synonyms for “fuzzy”: ill-defined, indefinite, indistinct, murky, obscure, unclear, vague, and so on. These are words that English-speaking people associate with fuzzy logic, fuzzy control, fuzzy identification, and fuzzy systems. They are not words that anyone would want associated with engineering systems, on which may depend large sums of money, or even worse, peoples’ lives. It is unfortunate that the word “fuzzy” was chosen to describe the type of identification and control described in this book. Japanese has no such negative connotations associated with the word “fuzzy,” hence systems utilizing fuzzy identification and control are far more prevalent in Japan than in English-speaking countries.
Fuzzy logic, as will be seen in Chapter 3, is modeled on the human reasoning process. Therefore, fuzzy logic is about as “fuzzy” as humans are. A well-designed system utilizing fuzzy logic to perform a task is roughly as dependable at performing the task as a human competent at performing the task would be. Two fuzzy systems designed by different designers to perform the same task may perform it slightly differently, depending on several choices made in the designs. This difference is analogous to the difference that would exist when two different people perform the task, or even the same person on different days. For example, two pilots will land an airplane slightly differently, but each can land it unfailingly ...