《Active Vibration Isolation Using an Electrical》.pdf

IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, VOL. 16, NO. 2, MARCH 2008 245 Active Vibration Isolation Using an Electrical Damper or an Electrical Dynamic Absorber Sang-Myeong Kim, Stanislaw Pietrzko, and Michael J. Brennan Abstract— This paper describes a theoretical and experimental tation of a skyhook damper for vibration isolation, where an ac- study to show how an electrical damper or an electrical dynamic tuator is collocated with a sensor attached to a piece of equip- absorber, implemented using an electromagnetic actuator and an ment at one end and supported by a base structure at the other accelerometer, can control vibration transmission through a vibra- tion isolator. The electrical damper is realized by feeding back the (i.e., structure-borne actuator installation) [3]. For a true skyhook equipment velocity to the actuator with constant gain. The elec- damper to be realized, the base motion should not be affected trical dynamic absorber is realized by feeding back the equipment by the vibration induced by the actuator (i.e., a weakly coupled acceleration through a second-order low-pass filter. Because it is base). In such cases, structure-borne actuators can be regarded found that the plant on a flexible base is asymptotically similar to as grounded and the electrical dampers are exactly equivalent to that on a rigid base, the optimal parameters of the control filter mechanical dampers. The control system is therefore uncondi- are determined analytically, independent of the base dynamics. Ex- perimental results show that the electrical dynamic absorber has tionally stable. Kim et al. [4], [5