Dynamic control allocation for attitude stabilization of spacecraft considering actuator misalignment

A backstepping design based adaptive control algorithm is developed for attitude stabilization of a rigid spacecraft, in which the uncertainties of actuators misalignment and external disturbances are considered. Lyapunov stability analysis shows that the attitude and angular velocity converge to zero, and an novel updating law is employed to implement attitude control law as well, in which the possible singularity problem caused by the estimation of uncertainties due to actuator misalignment is avoided effectively. In addition, a dynamic control allocation is investigated to distribute the desired control command among redundant actuators. This method extends the conventional quadratic-programming control allocation by penalizing the previous step before sampling intervals and minimize the energy consume. Finally, a numerical simulation example for a spacecraft attitude control system is included to illustrate effectiveness and feasibility of the proposed control scheme.