UNCERTAINTY IMPACT ON MICRO-VIBRATION CONTROL OF AN ORBITING LARGE ADAPTIVE SPACE STRUCTURE

Large deployable structures are required for the advancement of modern space activities. A wide variety of EO (Earth Observation) satellites are actually using and will profit by large antenna systems supported by truss-like structures with low mass and stiffness. A net of smart actuators can be embedded in the supporting frame elements to make the structure adaptive itself and to limit undesired elastic vibrations. In the present paper, the supporting structure of a very large mesh reflector is investigated. An optimization procedure has been carried out to evaluate the damping efficacy of the actuators. After having assessed the best authority of the devices belonging to the active net, a control strategy has been implemented to coordinate their simultaneous action. One of the most relevant issue to ensure a good performance of a spacecraft integrated control strategy is related to its robustness when some uncertainty parameters are considered at design stage. In addition, the properties of space modules may be affected by slight changes due to launch loads. The effects of the attitude control authority and its robustness to uncertainties on mechanical and elastic parameters of both passive structure and actuators have been analysed and discussed.