Attitude Stabilization Control for Underactuated Spacecraft: A Predefined-Time Method

The attitude controller design for the underactuated rigid spacecraft is addressed by considering that there are only 2 reaction wheels in the spacecraft. Most of the existing attitude control methods for underactuated spacecraft suffer from long system state convergence times and large overshoots. To improve the rapidity and stability of the attitude control system, in this paper, the predefined-time control technique is investigated for solving the attitude stabilization control issue for the underactuated spacecraft for the first time. By combining the sliding control method, a kind of predefined-time attitude stabilization control scheme is developed for the underactuated spacecraft. It is shown that the attitude variables and the angular velocity of the underactuated spacecraft are convergent into 2 non-empty sets within a predefined time by theoretical analysis. The simulation results illustrate the predefined-time convergence of the presented control scheme. In addition, the advantages of the proposed control strategy in this paper are demonstrated by comparing it with some existing control methods.