Ichiro Nagashima

Variable gain feedback control technique of active mass damper and its application to hybrid structural control

A systematic design procedure and an algorithm are devised for variable gain feedback (VGF) control of buildings with active mass damper (AMD) systems. The limit of the stroke length of the auxiliary mass, which is considered to be one of the most important physical constraints for application of AMD systems to actual structures, is studied. A set of variable feedback gains is designed as a function of a single variable that indicates a trade-off between the reduction of the building response and the amplitude of the auxiliary mass stroke, and this variable is on-line controlled to keep the amplitude of the auxiliary mass stroke constant, and within its limits. A design method of static output feedback controller for modal control of buildings with non-classical damping is also presented. Next, an efficient control method for hybrid structural control is developed, with combined use of the VGF control and the static output feedback control. It is shown through numerical examples that the proposed control method effectively adapts the control performance according to the variation in the intensity level of the external excitations in such a manner that the amplitude of the auxiliary mass stroke is kept within its limits and the control power is restrained as well. The application range of the AMD systems is thereby improved significantly.