Fuzzy control; evaluative expressions; fuzzy/linguistic IF-THEN rules; linguistic description

This paper is devoted to the original idea of fuzzy control --- to apply genuine linguistic description of a control strategy. We present the concept of fuzzy logic control which differs from the generally used techniques (based on Mamdani-Assilian or Takagi-Sugeno rules). The leading idea is to ``teach'' computer to ``understand'' genuine linguistic description of a control strategy and follow it analogously as people do. Our technique applies mathematical theory of the meaning of special expressions of natural language and mathematical theory of formal logical deduction on the basis of (vague) linguistic descriptions. The result is a specific control technique which has several advantages, namely intelligibility, robustness, generality, and also adaptation and learning. We present several examples and mention practical applications.