A soft 6-axis active vibration isolator

The paper presents analytical and experimental results with a 6-axis actively controlled vibration isolator. The isolator was designed to attenuate vibrations from reaction wheels, cryogenic coolers and other noisy machines located on board precision optical-class spacecraft. It consists of six active struts each of which includes an electromagnetic voice coil actuator in parallel with a soft spring. Six decoupled analog controllers were used to close broadband feedback loops around six force sensors and the isolator multi-axis transmissibility was measured with twelve accelerometers (six on the noisy side and six on the quite side). Experimental results show a ten-fold improvement in performance over passive isolation alone.