In this paper, conventional and hedge - algebras - based fuzzy controllers, respectively denoted by FC and HAFC, are designed to suppress vibrations of a three - story building against earthquake. The structural system is simulated against the ground accelerations of the El Centro earthquake in USA on May 18th, 1940; the Northridge earthquake in USA on January 17th, 1994 and the Kobe earthquake in Japan on January 16th, 1995. | Vietnam Journal of Mechanics, VAST, Vol. 33, No. 2 (2011), pp. 79 – 94 ACTIVE CONTROL OF A THREE - STORY BUILDING USING HEDGE - ALGEBRAS - BASED FUZZY CONTROLLER Bui Hai Le Hanoi University of Science and Technology Abstract. In this paper, conventional and hedge - algebras - based fuzzy controllers, respectively denoted by FC and HAFC, are designed to suppress vibrations of a three story building against earthquake. The structural system is simulated against the ground accelerations of the El Centro earthquake in USA on May 18th, 1940; the Northridge earthquake in USA on January 17th, 1994 and the Kobe earthquake in Japan on January 16th, 1995. The control effects of FC and HAFC are compared via the time history of the story displacements of the structure. Keywords: Active control, fuzzy control, hedge algebras, earthquake. 1. INTRODUCTION Undesired vibrations result in structural fatigue, lowering the strength and safety of the structure, and reducing the accuracy and reliability of equipments. The problem of undesired vibration reduction is known for many years and it has become more attractive nowadays to ensure the safety of structure, and increase the reliability and durability of equipment [1,2]. A critical aspect in the design of civil engineering structures is the reduction of response quantities such as velocities, deflections and forces induced by environmental dynamic loadings (., wind and earthquake). In recent years, the reduction of structural response, caused by dynamic effects, has become a subject of research, and many structural control concepts have been implemented in practice [3-7]. Depending on the control methods, vibration control in the structure can be divided into two categories, namely, passive control and active control. The idea of passive structural control is energy absorption, so as to reduce displacement in the structure. Recent development of control theory and technique has brought vibration control from passive to active
