Semiactive vibration suppression with electrorheological-fluid dampers

Semiactive vibration suppression with electrorheological (ER)-fluid variable dampers Is proposed and demonstrated to be a robust approach to suppressing the vibration of space structures. The principal characteristics of an ER-fluid variable damper are measured, and a simple mathematical model of the damper is proposed. Based on the mathematical model of the damper, several semiactive on-off control laws are proposed. Their performance is investigated through both numerical simulations and experiments of cantilevered truss beams with ER-fluid variable dampers. Simulation results indicate that most of the proposed laws result in much more effective vibration suppression than is obtained when using an optimally tuned passive system. Under an ill condition, they are also shown to be much more robust than linear quadratic Gaussian active vibration controls whose vibration suppression performance is almost the same. A semiactive vibration suppression experiment with a cantilevered ill-bay truss beam demonstrates that vibrations are suppressed effectively by the ER-fluid variable damper.