Attitude stabilization control for rigid spacecraft with actuator misalignment and saturation

A novel control scheme is presented in this work to address the attitude stabilization problem in the presence of actuator saturation, misalignment and lack of inertia information. Taking a hyperbolic tangent function in its formulation, the control signal explicitly obeys a known maximum-torque constraint. Considering the possible actuator misalignment, a dynamic attitude gain is introduced to accommodate the unknown but bounded configuration uncertainty. The configuration uncertainty assumption is this work is a relatively mild one. The saturated controller can be viewed as smooth nonlinear proportional-derivative control law. Asymptotical convergence of the closed-loop attitude system is guaranteed theoretically. Simulations have been carried out to demonstrate the effectiveness of the proposed strategy.