Large angle attitude maneuver control for rigid spacecraft with delayed inputs and disturbances

Time delays and disturbances are two phenomena which influence a spacecraft performance in the real world applications. First, the stability problem for a spacecraft system in the presence of time-delay systems is investigated. It is assumed that there exists an unknown constant time delay in the inputs (actuators) and only its upper bound is known as priori. The simple conditions for the stability of nominal systems are derived. Second, this paper is dedicated to examine the robustness of the developed controller with respect to model uncertainties and external disturbances. Based on input-to-state stability concept, it is proven that the proposed controller can drive the closed-loop trajectories to a small region in the neighborhood of the origin in the presence of external disturbances and model uncertainties. The response of the closed-loop system under large angle attitude maneuver is simulated to illustrate the effectiveness of the design.