Optimal linear quadratic Gaussian controller design for a flexible spacecraft simulator

Abstract

The experimental verification of active control methods for vibration suppression of large flexible structures in space is essential for precision optical and military payload operations. The Flexible-Spacecraft Simulator (FSS) at the Naval Postgraduate School is designed for testing such control designs. The experimental setup simulates the pitch axis motion of a rigid body spacecraft with a flexible antenna support structure connected to a rigid reflector. A twenty-four state finite element analytical model is used to characterize the flexible appendage. Piezoelectric sensors and actuators are used for feedback control for vibration suppression. In addition, an external infrared camera provides direct feedback of the flexible structure's elbow and tip displacements and rotations. A Multiple-Input- Multiple-Output (MIMO) linear quadratic gaussian (LQ(t) controller is designed using linear quadratic regulator (LQR) optimal control theory and an optimal Kalman estimator as the state observer to meet desired performance specifications. The objective is to minimize the motion of the reflector. (AN)