High-precision instruments such as electron microscopes and
coordinate measuring machines are very sensitive to internal and
external vibrations. There are two types of techniques to isolate
and control the vibrations, namely active and passive isolation.
Active isolation limits or controls the vibrations near the sources;
whereas passive isolation protects the instrument from the effect
of surrounding vibrating sources. Lei and Benli [1] and Collette
et al. [2] stated that the active isolation was more effective than
the passive isolation, especially for low frequency vibration isolation
purposes, however it was not a practical and economical solution
for external ground-borne vibrations caused by heavy vehicles
such as trucks and crawler vehicles [3]. Due to cost problems and
uncertainty of ground borne vibrations, passive isolation is usually
preferred to meet limit vibration criteria for the proper operation
of the high-precision instruments.
Working machinery and human activities in buildings are the
main sources of internal vibrations whereas, external vibrations