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An efficient and simple non-linear active control method called Bounded-Force Control (BFC) method has been developed. The theoretical development and application examples of the BFC method has been presented in several publications 1-3 where it was shown that the BFC is more efficient than the Linear Quadratic Regulator (LQR) method in terms of maximum control force and power requirements when applied to an Active Tuned Mass Damper (ATMD) system. Following a brief review of the fundamental concept of the BFC and a discussion of its main advantages, the results of an experimental investigation using a three-storey shear building model excited by a shaking table and controlled by an electromagnetic linear motor are presented. The experimental results were in perfect agreement with the analytical results, thus confirming the validity of the proposed BFC algorithm.

A new control strategy to improve a tuned mass damper (TMD) is developed for the vibration control of a large structure subjected to external disturbances. The feedback gain of the proposed algorithm is linear to the response acceleration of the primal system and it is optimized in the frequency domain under a harmonic excitation. According to this method both the feedback gain and the TMD parameters are optimized in the frequency domain and they are expressed in a set of closed form solutions. The performance of the proposed control method is discussed and compared with that of a passive TMD.

A hybrid mass damper system has been developed with a view to counteracting wind- and earthquake-excited vibrations of large high-rise building structures. In order to eliminate the large space needed to accommodate a pendulum-type mass damper adapted to the long period of high-rise building, mechanism has been devised for suspending the auxiliary mass on a V-shaped rail sliding on rollers. The base angle of the V-shaped rail is varied for adjusting the natural period of the mass damper system. A suboptimal algorithm based on the minimum norm method has been adopted for designing the auxiliary mass driving system. Three units of this damper system, each equipped with auxiliary mass weighing 110 tons, have been installed on a 52-story building. Satisfactory performance conforming in all practical aspects with design has been verified from vibration test on actual building after installation. As sequel, the functioning of the system during the first year of service is also reported.