Vibration control of uncertain structures with actuator saturation using hedge-algebras-based fuzzy controller

In this study, the problem of vibration control of structures involving parameter uncertainties and actuator saturation using hedge-algebras-based fuzzy controller (HAC) is presented. When structural damping and stiffness cannot always be measured easily and precisely, their uncertainties are assumed to be norm-bounded. The proposed controller is designed based on hedge algebras theory, where inherent order relationships between linguistic values of each linguistic variable, determined by isomorphisms mapping called semantically quantifying mapping based on few fuzziness parameters of each linguistic variable instead of using any fuzzy sets, are always ensured. The performance of the proposed controller is investigated by numerical simulations on active control of a benchmark three-storey building structure with active bracing system subjected to excitation of typical earthquakes. A conventional fuzzy controller, designed based on parameters similar to those of HAC, is also considered for the purpose of comparing effectiveness between controllers in order to shown advantages of the proposed method.