Document Type


Publication Date


Publication Title

NASA CR-193268




The main objectives of our research are to present a self-contained overview of fuzzy sets and fuzzy logic, develop a methodology for control system design using fuzzy logic controllers, and to design and implement a fuzzy logic controller for a real system. We first present the fundamental concepts of fuzzy sets and fuzzy logic. Fuzzy sets and basic fuzzy operations are defined. In addition, for control systems, it is important to understand the concepts of linguistic values, term sets, fuzzy rule base, inference methods, and defuzzification methods. Second, we introduce a four-step fuzzy logic control system design procedure. The design procedure is illustrated via four examples, showing the capabilities and robustness of fuzzy logic control systems. This is followed by a tuning procedure that we developed from our design experience. Third, we present two Lyapunov based techniques for stability analysis. Finally, we present our design and implementation of a fuzzy logic controller for a linear actuator to be used to control the direction of the Free Flight Rotorcraft Research Vehicle at LaRC.

Original Publication Citation

Abihana, O. A., & Gonzalez, O. R. (1993). Design and implementation of fuzzy logic controllers. Thesis final report, 27 July 1992 - 1 January 1993. NASA Contractor Report: NASA CR-193268. Hampton, VA: NASA Langley Research Center.


0000-0001-9503-4171 (Gonzalez)