A 6-DOF micro-vibration isolation platform based on the quasi-zero-stiffness isolator

Micro-vibrations generated by rotating machinery could influence the working performance of the precise instruments equipped in industrial facilities, aircraft, ships, etc. Isolation systems are thus essential for preventing the high-sensitive instruments from being disturbed. In this work, a 6 degrees-of-freedom (DOF) micro-vibration isolation platform is proposed based on the quasi-zero-stiffness (QZS) isolator. The structure of the isolation platform is a conventional Stewart mechanism equipped with the QZS isolators in each leg. To analyze the stiffness of the leg, the static analysis is carried out. Afterwards, the stiffness of the platform in six directions are also discussed. Moreover, the dynamical equations of the isolation platform are formulated by the Lagrange Equation. Finally, the dynamic response of the proposed model is investigated and compared with the linear case whose stiffness of the leg is linear. The results show that the newly designed QZS platform in this work has a good isolation performance, which can attenuate the external vibrations significantly within a broad frequency band. Parametric analysis shows that the structure parameters, damping and excitation amplitude have a great influence on the isolation performance of the QZS platform. Delightfully, the result of indicates that, (a) the newly designed QZS platform is able to provide an excellent isolation performance in all the six DOFs, which advances the dynamic study of multi-dimensional QZS vibration isolation; (b) The multi-dimensional vibration isolation platform is innovatively designed using geometric nonlinear technology, there is no influence of the magnetic sources to the precision instruments when compared with the previous designs; (c) the regulation mechanism of the structure parameters of the QZS isolation platform on the dynamic transmission characteristics of the system is revealed, which indicates that the platform is particularly suitable for micro-vibration isolation whose vibration magnitude and frequency are quite low.