State observation and variable structure control of rotational maneuvers of a flexible spacecraft

Abstract

In this paper, a state observation approach and a variable structure control strategy are presented for single-axis large-angle maneuvers of a flexible spacecraft. According to special structures of high-dimensional and nonlinear equations of the motion, a linear time-varying and partial-order state observer with exponentially decaying error is constructed so that the elastic modes of the spacecraft can be available at all instants of time using fewer sensors. Furthermore, a dynamic output feedback variable structure control using outputs of the system and states of the observer is applied to the flexible spacecraft. Some new properties of this simultaneously observed and controlled system are presented. Simulation results demonstrated for a control maneuver from one attitude to another effectively justify the solutions developed in this paper.