Experimental Verification of an Optimal Linear Controller for a FlexibleStructure

摘要

Nanometer accuracy in many space applications requires that sensors be isolatedfrom vibration disturbances by the main spacecraft body. The Flexible Spacecraft Simulator (FSS) at the Naval Postgraduate School is designed for testing multiple control system designs. The experimental setup simulates a microgravity environment for a flexible structure. A twenty four state finite element model is used to characterize the flexible appendage. Piezoelectric ceramic wafers bonded to the structure are the actuators and sensors. A VisionServer external infrared camera provides direct feedback of the flexible structure's elbow and tip displacements to sub-millimeter accuracy. A Multiple Input Multiple Output (MIMO) Linear Quadratic Gaussian (LQG) controller is experimentally compared with a Positive Position Feedback Velocity feedback controller. The damping is increased on the order of 825% for both control implementations. The objective is to minimize the disturbance of the tip of the flexible structure, representing the reflector support point.