A 3-DOF modular vibration isolation system using zero-power magnetic suspension with adjustable negative stiffness

This paper presents a 3-DOF vibration isolation system combining three vibration isolation modules. Each vibration isolation module is constructed by connecting a positive stiffness spring in series with a negative stiffness spring. The positive and negative spring is realized by an active controlled magnetic suspension. In the previous system, conventional zero-power control system has been used to generate negative stiffness, and the stiffness depends on the capacity of the permanent magnets or the gap-force coefficient of the magnets. This is one of the bottlenecks in the fields of application of zero-power control where the adjustment of stiffness is necessary. On the other hand, the suspension system was used in the vertical and horizontal directions, which made the system complicated. To overcome the above problems, a vibration isolation system is developed with three modules connected by parallel mechanism. Some experiments have been carried out to measure the efficacy of the control system, as well as the vibration isolation system.