Abstract: A method of attenuating vibrations, and a vibration attenuating actuator for attachment to a vibration transmitting structural member include an annular proof mass for attenuating vibrations. The proof mass is concentrically mounted without bearings on the strut so as to attenuate vibrations being transmitted therethrough without imparting a moment to the strut, and without affecting the structural integrity of the strut. The annular proof mass is moved parallel to the strut's longitudinal axis so that the actuator imparts a vibration attenuating force coaxial with the strut's longitudinal axis. The actuator may be used with feedforward and feedback controllers.

Abstract: An active isolation device and method reduces the transmission of vibrations from interconnected elements. The device maintains a high stiffness between interconnected elements while actively reducing the transmission of relative movements, such as vibration. In one embodiment, the device uses accelerometers to measure the vibrations experienced by each of the interconnected elements and selectively operates an actuator between the two elements to maintain the position of one of the elements. In another embodiment, plural of the devices are used cooperatively to reduce the vibrations that would otherwise be transmitted from one element to a platform, permitting simultaneous control of multiple degrees of freedom of movement.

Abstract: A high precision linear actuator for compensating short stroke, high frequency vibrations in a space deployed structure comprises a set of cylindrical magnetic pole pieces affixed to respective ones of a pair of graphite flexures, that are mounted to a thermally conductive cylindrical housing, which is to be affixed to the space deployed structure. Reaction against the "proof mass" pole pieces is achieved by a magnetic field produced by set of stationary magnetic coils that surround the pole pieces and are energized by a vibration compensation reaction current supplied from a sense/control processor. Coaxial with and mounted integrally with the cylindrical pole pieces of the proof mass is an internal accelerater, which generates an output signal representative of the force to which the proof mass is subjected.