Large Flexible Structure Control Technology Experiment and Facility Design 1

Abstract A new facility is being developed for experimental validation of static and dynamic control technologies associated with large flexible space structures. The test article resembles a wrap-rib antenna design, with a horizontal dish of 7.2 meter diameter consisting of 12 ribs attached to a rigid, central hub and interconnected with stretched wires under tension, and a 3.6 meter long flexible boom hanging vertically downward from its center. A complex levitation system using counterweights and low friction pulleys provides support of the structure to prevent its collapse due to gravity. Sensing instrumentation includes a two-axis hub-angle sensor, 28 rib displacement sensors, and 16 electro-optical sensor targets which can be moved about fairly easily. A two-axis torquer acts on the hub, and one speaker-coil actuator on each of the 12 ribs completes the complement of actuators. The facility is scheduled to be operational in nine months at which time experimentation in the areas of Static Shape Determination and Control, Dynamic Identification, Unified Modeling/Control Design, and Adaptive Control will commence This paper gives a system level analysis of the facility design, provides an overview of its modeling, presents initial simulation results giving open loop response to impulsive inputs, and discusses the planned technology experiments intended to be performed using the facility