Abstract
This paper presents the results of a two-year proof-of-concept program to prepare for the foreseen needs to master microvibrations on-board high pointing accuracy platforms, through the design, prototyping and experimental validation of four microvibration control systems: (1) an elastomer-based passive isolator for six degree-of-freedom isolation of a disturbance source (reaction wheel or mechanical cooler). Attenuation performance exceeding 20 dB above 25 Hz and 40 dB above 50 Hz has been demonstrated. (2) A passive vibration damping system, based on distributed piezoceramic wafers connected to a dissipative electrical circuit. Such simple, standalone devices are shown to have interesting applications (up 20 dB attenuation) when applied to the damping of a local flexible mode with concentrated strain energy. (3) Active damping with two-dimensional smart structures by using positive position feedback on pairs of collocated piezo-electric wafers used as sensors and actuators. Modal damping from 10 to 20 dB on the best controlled modes has been demonstrated, but some less controllable modes remain essentially undamped. (4) A centralized anti-phase control scheme operating on distributed sensors and actuators to compensate for stationary harmonic disturbances. The sensors are accelerometers and the actuators piezoelectric wafers or active struts equipped with a stack of piezoceramic wafers. The harmonic disturbance (for instance a reaction wheel unbalanced force) is estimated and compensated, with demonstrated attenuation from 30 to 40 dB.
Follow-on activities in the domain are focused on the development of flight prototypes of the two active control concepts, for validation through on-orbit experimentation.
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