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Simulation and experiment on the performance of a passive/active micro-vibration isolator

In this paper, a passive/active hybrid vibration isolator is proposed to isolate micro-vibration. The passive element of the isolator is a spring-damper constructed with oil-filled corrugated pipes and the active one is an inertial actuator. A numerical model of the isolator is established through theoretical modeling of the stiffness and damping of the spring-damper and the subsystem synthesis method. On the basis of this model, frequency response functions of the disturbance and control channels are computed to describe the characteristics of the isolator. An adaptive control method based on the least mean squares algorithm is adopted to suppress transmission of micro-vibration caused by tonal, chirp or random disturbances. To verify the modeling as well as the isolation performance, tests and experiments are carried out and the results show that the computation of stiffness is effective and the passive element of the isolator has a reasonable amplification factor and a decreasing slope of –40 dB/decade. Furthermore, the active element is able to achieve remarkable attenuation of random and tonal disturbances.