Study On Variable Stiffness Vibration Isolator

The traditional passive vibration isolation system can reduce the vibration transmission greatly while the interrupt frequency is more than 2^1/2 times its resonance frequency.But to the lower frequency vibration, it does not work because the restricts of structure space and stability.The semi-active isolation technique based on adjustable parameter isolator is a good choice.The electromagnetic spring with tooth structure is adopted in this paper to adjust the stiffness of isolator, which make the isolator work with different stiffness in different excited frequencies. So the isolation performance is improved as the resonance frequency is eliminated in a broad band.The variable stiffness vibration isolator in this paper is designed on the basis of the vibration isolation theory, the design data of stepping motor and the related research information. The electromagnetic spring used in the vibration isolator is designed by the aid of ANSOFT, which is finite element analysis software for electromagnet. The design steps of variable stiffness vibration isolator are summarized for the further development. Then the semi-active control scheme is discussed.The prototype of variable stiffness vibration isolator is developed and its characteristics are tested after constructing the test bed. Firstly the static property of electromagnetic spring is measured. The result shows that the static stiffness of electromagnetic spring has a good linear property in the permitted displacement and it can completely fulfill the role in this paper. Secondly, another experiment is conducted about the isolating property for this variable stiffness vibration isolator. The result demonstrates that the isolator achieves the aim of moving the resonance frequency in lower frequency to improve the performance of vibration isolation. At last, the semi-active isolating experiment with different electromagnetic stiffness is conducted to for single frequency in low-frequency band. The result shows the isolator with bigger stiffness not only solves the resonance of isolation system in low-frequency...