Electronic circuits dedicated to fuzzy logic controller

The viewpoint of this paper is based on the hypothesis that human expert know-how is represented and stored in natural fuzzy linguistic terms. Know-how is obtained by the summarization of numerous experiences over a long period of time and expressed with a set of fuzzy IF-THEN rules. This paper describes the electronic circuits, both in current and voltage modes including semiconductor chips that were developed from 1980–1997, and dedicated to fuzzy information processing. A set of fuzzy IF-THEN rules with a fuzzy inference engine has a good ability to describe complicated systems that are nonlinear, time-varying, multivariable, chaotic, unpredictable, etc. The focus of this paper lies not only on a fuzzy inference engine and defuzzifier, but also on a fuzzy memory device, fuzzy PLA, a grade-controllable membership function circuit and time-sweeping mode fuzzy computer hardware. Distinctive features of a fuzzy logic controller are presented by employing benchmark tests, such as an inverted pendulum, wine glass stabilization and mouse stabilization. These experimental results show that fuzzy logic control is effective, even in cases where the mathematical model is not available.