PID plus fuzzy controller structures as a design base for industrial applications

This paper investigates the practical ways of designing effective combinations of classical PID controllers and emerging intelligent technologies for real-life industrial projects. It analyses the evolution of fuzzy controller (FC) design methodology. Based on the analysis, structures and methods that combine both approaches are proposed and considered. The paper is not intended to develop a mathematical theory, but to give some practical recommendations on replacing control by a human operator control with fuzzy control, and an on-line parameter tuning of FC parameters. These two main points are illustrated with two application projects, which are studied in greater detail. The first one includes the design of a FC supervising a PID control system in an automatic aircraft guidance system. The second project describes the tuning of the scaling factors of a fuzzy PID-type controller with other fuzzy systems, used in the excitation control of a synchronous power generator connected to an infinite bus through a transmission line. (C) 2000 Published by Elsevier Science Ltd.