Abstract: A virtual sky hook vibration isolation system provides reduction of transmissibility at resonance without significantly increasing high frequency transmissibility. Isolation is achieved passively and without the need for an inertial reference frame. Design of the primary and secondary suspension systems is performed concurrently to achieve the desired performance. The primary suspension affords the necessary static deflection properties and high frequency isolation. The secondary system couples to the system at resonance and provides damping to the dynamic response. This combination yields the isolation benefits of the skyhook damper concept. The penalty for this performance is the necessity of a secondary spring-mass-damper device. However, results indicated that good performance can be achieved using a relatively small secondary mass (5% of the primary mass).

Abstract: A whole-spacecraft passive isolation system consisting of a plurality of titanium flexures that act as soft springs to isolate a satellite from its launch vehicle is improved by the addition of piezoceramic wafers attached to the flexures. A low-pass filter feedforward controller is used to cancel out disturbances by applying out-of-phase signals to the piezoceramic wafers thereby creating a hybrid isolation system that significantly reduces the dynamic loads on the spacecraft.