Decoupling control law for structural control implementation

Multi-story buildings, subjected to wind or earthquake excitation, can be m odeled as multi-degree of freedom (MDOF) systems defined by a set of couple d second order ordinary differential equations. In this paper, the dynamic coupling characteristics of multi-story building are examined, and it is fo und that the coupled property in a system can be described as a positive fe edback from the control theory point of view. This positive feedback proper ty of a MDOF system may intensify structural vibration. For the structural control implementation, open-loop and closed-loop decoupling control laws a re proposed. All coupled "channels" of the system are "broken off" when the vibration control design is based on the proposed control laws. A complex MDOF structural system, therefore, is equivalent to a set of single degree of freedom (SDOF) systems, and the control design can be carried out indepe ndently for any specific degree of freedom. Thus, the proposed control laws provide an efficient tool by which the vibration of a selected floor can b e suppressed without any effect on its neighboring floors because the contr ol is one to one. Meanwhile, the computational procedure of the control des ign can be significantly simplified because all analyses and design are con ducted based on SDOF systems. (C) 2001 Elsevier Science Ltd. All rights res erved.