Robust finite time control of heliostationary flight over asteroids

Maintaining a heliostationary flight over an asteroid is challenging because of the complex dynamical environment. During exploration, external disturbances and uncertainties make it difficult for a spacecraft to stably hover at the libration point to complete its mission. In this paper, a globally robust finite time control law is proposed to solve this problem. First, we design a time variant sliding mode control law for the convergence of the tracking error to zero. Based on this, a nonsingular terminal sliding mode control law is designed to maintain the underlying track error at zero. The performance of the proposed control law is demonstrated through numerical simulations.