  This study presents the analysis and design of a novel quasi-zero-stiffness
(QZS) based vibration sensor system for measuring absolute displacement of
vibrating platforms/objects. The sensor system is constructed by using positive
and negative-stiffness springs, which makes it possible to achieve an
equivalent QZS and consequently to create a broadband vibration-free point for
absolute displacement measurement in vibrating platforms. Theoretic analysis is
conducted for the analysis and design of the influence of structure parameters
on system measurement performance. A prototype is designed which can avoid the
drawback of instability in existing QZS systems with negative stiffness, and
the corresponding data-processing software is developed to fulfill time domain
and frequency domain measurements simultaneously. Both simulation and
experiment results verify the effectiveness of this novel sensor system.
