Adaptive Nonsingular Predefined-Time Control for Attitude Stabilization of Rigid Spacecrafts

This article proposes a novel adaptive nonsingular predefined-time control strategy for rigid spacecrafts with inertia uncertainties. Following the backstepping recursive design procedures, an adaptive attitude controller is systematically presented to ensure that the spacecraft attitude can converge into a small region around the origin within a predefined time, which can be explicitly determined in advance by assigning a simple parameter. Moreover, by designing quadratic functions in the controllers, the singularity can be avoided directly without using any filters or piecewise continuous functions, such that the stability analysis becomes more concise and straightforward. Simulations are conducted to show the effectiveness of the presented method.