Flexible spacecraft control using robust feedback linearization

Abstract

In this paper, the problem of automated attitude control of a 3D nonlinear flexible spacecraft is investigated. Two nonlinear controller designs are presented. These controllers are composed of feedback linearization and μ-synthesis controllers. The first controller is based on classic feedback linearization, while the second one is robust feedback linearization. The robust feedback linearization method gives a linearizing control law that transforms the nonlinear system into a linear system based on operating condition. It is assumed that only three torques in three directions on the hub are used. Actuator saturation is considered in the design of controllers. The performances of the proposed controllers are compared in terms of nominal performance, robustness to uncertainties, vibration suppression of panel, sensitivity to measurement noise, environment disturbance and nonlinearity in large maneuvers. To evaluate the performance of the proposed controllers, an extensive number of simulations on a nonlinear model of the spacecraft are performed. Simulation results show the ability of the proposed controller in tracking the attitude trajectory and damping panel vibration. It is also verified that the perturbations, environment disturbance and measurement errors have only slight effects on the tracking and damping performance. Copyright © 2010 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.