Abstract
This paper presents a new seismic isolation system which is composed of two layers with a magneto-rheological fluid(MR) damper on each layer. We design a gain-scheduled controller based on H∞ theory for the semi-active seismic isolation system for a multi-degree-of-freedom structure.,so that the lower layer has a role to isolate the vibration transferred from seismic excitation and the upper layer has a role to suppress the structural vibration. By dividing the roles into two layers, it is expected that the total damping force of the traditional seismic isolation system is reduced and performance of isolation is held or improved. It is demonstrated by simulation and experiments that seismic responses by the new isolation system are compared with those by the one-layer isolation system. It is verified that the new system is superior to the traditional one and the gain-scheduled controller designed is effective for seismic isolation.
