Identification and frequency shaping control of a vibration isolation system

In the present paper, a vibration isolation control problem is considered for the case in which forced vibration disturbances that have a narrow-band frequency component are applied to a system. Such a control problem appears in the vibration isolation control of a rotating machine. Velocity feedback control including notch-filters attenuates the effects of such narrow-band frequency disturbances, but parameter tuning of a controller is difficult because the vibration isolation performance changes dramatically according to slight discrepancies in the controller parameters. In such cases, a direct frequency shaping method such as the H∞H∞ control is suitable for the controller design. In the present paper, a vibration isolation control problem for a mechanical experimental system, which simulates the characteristics of a rotating machine in space, is considered. A system model was created by performing system identification experiments, and a controller was designed by a frequency shaping method based on the H∞H∞ control. Control experiments were carried out successfully, and the controller was verified to provide the expected performance.