Ahybrid mass damper combining a tuned mass damper and an actuator is a powerful structrual control device ・ for reducing the response of a tall building when subjected to strong winds . To clarify the characteristics of a hybrid mass damper, the energy flow between the tall building and the mass damper is evaluated comparing to a tuned mass damper or an active mass damper. The energy flow is decomposed into seve [al components to identify the roles of a spring , a dashpot and an actuator , The

more »

... cQIltrol algorithms for a hybrid mass damper are also investigated consider − ing optimum state feedback , acceleration feedback and displacement feedback contfols . It is shown that the simple acceleration feedback Qr displacement feedback centrol may achieve the same performance with the optimum state feedback control but requiring larger control forces and powers than the optimum state feedback control