A Compound Regulative Pneumatic Vibration Isolator With Quasi-Zero Stiffness Mechanism For Load Variable Instruments

Large precision instruments are essential for scientific research and precision manufacturing, which are extremely sensitive to environmental vibration. A compound regulative pneumatic vibration isolator (CRPVI) with quasi-zero stiffness mechanism which is built by combining four opposite horizontal air springs and one vertical air spring is presented to provide a micro-vibration environment. Multi-directional adjustments with adjustable stiffness have been designed to adapt to changes in the load on the instrument. Analytical models of the elastic restoring force and the dynamic response of the CRPVI are established. In order to determine the appropriate structural parameters, we theoretically discuss the influence of the geometrical parameters on the quasi-zero stiffness region, and a procedure of the CRPVI for variable load is presented. A test prototype has been built and experimentally verified that the designed vibration isolation components for measuring instruments are effective in providing better low-frequency vibration isolation for precision instruments with large loads.