Active Negative Stiffness Regulation and Precision Micro-Vibration Isolation Technology Based on Composite Feedback of Acceleration and Velocity

An active negative stiffness regulation and precision micro-vibration isolation technology (ANSVIT) based on composite feedback of acceleration and velocity is proposed to realize the low-frequency isolation of air floating isolators with heavy loads. Adjustable negative stiffness generated by acceleration feedback realizes low-frequency isolation, and absolute velocity feedback is combined to reduce the peak vibration transmissibility and improve isolation performance. The effects of feedback coefficients in the frequency domain are analyzed based on the dynamics model. And the relationship of feedback coefficients that achieves low natural frequency and lower peak vibration transmissibility than passive vibration isolation is derived to guide design. Furthermore, the effects of ANSVIT on vibrations in the low-frequency region, resonance region, and isolation region are investigated numerically in the time domain. Finally, an experimental setup is built, and experiments are conducted. Experimental results show that the introduction of ANSVIT attenuates the natural frequency by 61.54% and achieves lower peak vibration transmissibility and higher vibration level than passive vibration isolation. The promise of the proposed ANSVIT for improving the isolation performance is verified.