Ali Kasiri - Ph.D. Student, Aerospace Department, AMIRKABIR University of Technology
Farhad Fani Saberi - Assistant professor, Space Science and Technology Institute

A hybrid controller based on feedback linearization and model reference adaptive control scheme is derived using nonlinear dynamic of a rigid spacecraft. In fact, the proposed controller consists of two parts, first feedback linearization method is employed to cancel the couplings and nonlinearity of the dynamic equations to result in an equivalent linear system, and then we controlled thelinear dynamics of the spacecraft by model reference adaptive control. The combination of these two control laws brings unique capabilities for large-angle rotational maneuvers. Since there is always uncertainty in measuring the inertia of the satellite, the purpose of this study is to achieve the suitable performance of the controller in the presence of 10% uncertainty in the moment of inertia tensor. The tracking-error is described by the quaternion parameters vector and the body angular rate. Simulation results are presented to show that designed adaptive feedback linearization control has a great performance in resisting the external disturbances andcompensating the uncertainties of the system model.

adaptive feedback linearization, large-angle maneuver, spacecraft attitude control, agile spacecraft