Multi-Axis Attitude Control of Flexible Spacecraft Using Smart Structures and Hybrid Control Scheme

Abstract

This paper presents a hybrid control design approach for simultaneous three axis attitude manoeuvre and active vibration suppression of a flexible spacecraft, in the presence of sensor noises and external bounded disturbances. The spacecraft considered as a rigid hub with two elastic appendages embedded with piezoelectric sensor/actuator patches. Using a modified sliding mode control by introducing a synthesized sliding manifold ensures that the spacecraft follows the shortest possible path to the desired orientation and highly reduce the switching action and excitation of flexible modes. A modified positive feedback scheme is developed to design a more symmetrical way to stabilize the vibration modes. Stability proof of the overall closed loop system is given via Lyapunov analysis. Numerical simulation results are presented to show the merit of this approach.