Vibration isolation controller design by frequency shaping

In this paper, we consider a vibration isolation problem of a vibration isolation system using an active damping control. The active damping feedback control stabilizes vibration modes of the system. At the same time, the controller can improve vibration isolation performances. For example, if we know frequencies of disturbances in advance, we can shape the frequency response of the feedback control system in order to reduce the influence of the disturbance to the system. For this purpose, notch-filters are used in conventional methods. However, we sometimes spend time and effort on specifying the parameters of the filters because the control performance highly changes according to slight change of parameters of the controller. In this paper, we show a problem of a conventional design method and provide a method by frequency shaping using H-infinity control design.