ABSTRACT
Active vibration isolation involves the use of an active system to reduce the transmission of vibration from one body or structure to another. A broader definition would also include the reduction of vibration of a machine or structure by an active vibration absorber. Passive vibration isolation is covered adequately in many textbooks (see, for example, Bies and Hansen, 2009) and will not be discussed here. In the analyses discussed in this chapter, a constant force (or infinite impedance) source is assumed. That is, it is assumed that the driving force is independent of the structure and does not change significantly if the dynamics of the structure change. Although this idealised case is not often found in practice, the constant force assumption simplifies complex analyses, and the results obtained are indicative of what can be achieved in many practical cases.
