Micro-vibration isolation measurement platform using permanent magnet negative-stiffness devices and air springs

Environmental micro-vibration affects the accuracy of precision measurement devices. Passive isolation system can isolate most external vibration, decreasing its stiffness will improve isolation effect. Permanent magnet negative-stiffness device (PMNSD), which is mainly constructed from three permanent magnets, can decrease the system dynamic stiffness of isolation system without any effect to the static stiffness, when it is used parallel with positive-stiffness isolator. The mechanism of its negative stiffness is analyzed, and its stiffness is calculated by theory method and finite element method, it proves that the stiffness will decrease with the decrease of the initial air gap of magnets. A micro-vibration isolation platform using PMNSDs and air springs is constructed, it can carry many kinds of measurement instruments which weight 0-2000 Kg, keeping the system natural frequency under 1 Hz, it has good isolation capacity for micro-vibration over 2 Hz. The PMNSD will have greatly practical applications for its tunable negative stiffness, zero static stiffness, contact free, long life and so on.