Nonlinear local stabilization control of flexible satellite attitude system

Based on the polynomial sum of squares(SOS) techniques, a nonlinear local stabilization control approach is proposed for the problem of flexible satellite attitude maneuver and vibration suppression. According to the structural features of attitude system, a nonlinear local stabilization controller is developed and the complexity of attitude control design is reduced effectively by employing a separation principle for the reduced-order observer and state feedback. On this basis, the corresponding conditions of nonlinear local stabilization, which can be checked through convex optimization algorithms, are presented by using the SOS and S-procedure theory, and the analytical solution of nonlinear attitude controller can be constructed if the optimization problem is solvable. Finally, this method is applied to the attitude control of a flexible satellite and the simulation results show that both the fast large angle attitude maneuver and the vibration suppression are well realized.