A fuzzy set-theoretic regulator design for power plant components

A set-theoretic regulator design in which the bounds are fuzzy is proposed for power plant components. As a preliminary study, only box bounds, which are computationally much simpler than the ellipsoid bounds originally advocated in a book by F.C. Schweppe (1973), are considered. The definition of the membership function of a variable derived from fuzzy variables deviates from L.A. Zadeh´s (IEEE Trans. Syst. Man Cybern., vol.SMC-3, no.1, p.28-44, 1973) original work. A third-order example of a steam boiler, subjected to external load changes, is treated as an illustration of the theory. Results indicate that a range of allowed disturbance magnitudes is obtained for which the system does not violate a prespecified range of state and control constraints