Analysis And Design Of Array Combined Magnetic Negative Stiffness Mechanism With High Linearity In Large Stroke

Large-stroke near-zero and ultra-stable vibration reduction is the key to ensuring the normal operation of advanced manufacturing/measurement equipment and advanced optoelectronic equipment in major equipment for aerospace and navigation.The contradiction between near-zero stiffness and large bearing capacity is difficult to balance,and it is a common technical challenge faced by high-performance vibration isolation devices in limited space.Introducing the negative stiffness mechanism(NSM) in parallel with the positive stiffness mechanism is a good way to reduce the damping frequency and improve the vibration damping performance under the premise of ensuring the bearing capacity.However,the stiffness of the conventional NSM has a problem of large-stroke linearity difference,which results in difficulty in achieving near-zero damping frequency and insufficient vibration-stable stability,which seriously lags behind the development needs of advanced equipment.Partially supported by the National Science and Technology Major Project and the National Natural Science Foundation of China,this thesis proposes an array combined magnetic negative stiffness mechanism for the large load capacity and ultra-stability of the precision vibration isolation system,which has large stroke and high linearity stiffness characteristics and can realize large negative stiffness value.Effectively solves the problems faced by the MNS technology in the field of vibration reduction.Based on the analysis of the traditional MNSM,a combined magnetic negative stiffness mechanism composed of suction and repulsive magnetic negative stiffness mechanisms is proposed,and its magnetic analytical expression is derived.Through numerical calculation and comparison,it is found that compared with the simple suction type MNSM,the linear stroke of the combined magnetic negative stiffness mechanism with linearity less than 10% is increased by 228.6%,compared with the repulsion type MNSM by 253.8.%,achieves a large stroke and high linearity magnetic negative stiffness characteristics.Based on the modeling and analysis of the array magnetic negative stiffness mechanism,an array combined magnetic negative stiffness mechanism is proposed and its magnetic analytical expression is derived.Through numerical calculation and comparison,it is found that the negative stiffness value of the array combined magnetic negative stiffness mechanism is increased by 127.7% compared with the array suction type MNSM,which is increased by 181.3% compared with the array repulsion type MNSM.Large negative stiffness under large stroke and high linearity is achieved.According to the actual needs of the vibration isolation system,a magnetic negative stiffness mechanism is designed.The static stiffness measurement experiment and the vibration-reduction performance test of the MNSM are carried out.It is proved that the array combined magnetic negative stiffness mechanism increases the linear stroke with linearity less than 5% from 2.5mm to over 10 mm.The negative stiffness value of the the array magnetic negative stiffness mechanism is 47% higher than the traditional negative stiffness mechanism.Under the condition of 53.74 Kg load,the natural frequency of the vibration isolation system is reduced from 6.00 Hz to 1.25 Hz,offsets the system's positive stiffness of 95.66%,which proves that the large stroke and high linearity magnetic negative stiffness mechanism can effectively reduce the natural frequency of the damping system and has high stability.The research results of this thesis are part of the 2018 Hubei Province Technology Invention First Prize "Near-zero stiffness damping technology and device in nanometer precision manufacturing and measurement".This technology has now been adopted by immersion lithography vibration isolation systems and quantum communication antenna vibration isolation systems.