Active vibration damping of large satellite solar array panels

In the present study the active damping of large satellite solar array panel is investigated, with focus on reduction of selected resonances below 200 Hz. Therefore a demonstration panel with piezoceramic patch actuators was designed and tested. A model of the panel has been created with finite element software and converted into state space representation for further controller design. An Acceleration Feedback controller and a LQG controller have been developed and compared in simulations and experiments. The Acceleration Feedback controller is tuned to mainly damp vibrations of two selected modes. Due to a high modal density a compromise is made between filter damping and frequency. Otherwise ongoing filter phase shifts will interconnect controllers and may reduce modal damping or lead the system into instability. In spite of small controller interconnection, modal damping can be notably increased. For further improvement a LQG controller has been developed. A set of sensor positions is selected by grammians to well observe modes of interest. The weighting matrices of the controller are set up to utilize actuator performance, i.e. limits on actuator voltages are reached for a given excitation level. It can be shown that damping of focused modes is increased drastically while other modes are not affected by the controller. A representative demonstration panel has been created in laboratory. Its dynamic behaviour has been obtained by experimental modal analysis and system identification. There were some differences between experiment and simulation, thus the simulation model has been modified to adequate describe the panel motion. Both controllers were implemented on a real time system and their impact on modal damping has been verified by experiments. Damping performance agrees well with simulation, but controller interconnections appeared differently in experiments.