Finite-time attitude control of rigid spacecrafts using immersion and invariance

This paper proposes two constructive approaches to design an attitude controller for a rigid spacecraft. Standard I&I control strategy gives a new insight into the attitude controller design where the manifold is rendered invariant and attractive. Finite-time I&I control strategy improves the performance by driving the off-the-manifold variable to converge to zero in finite time. Detailed theoretical proof and derivation of finite time are provided. Performance of the proposed controllers are demonstrated by simulations, and comparison with backstepping method is also given to prove the effectiveness of the proposed control strategies.