Robust MPC Autonomous Landing of Tethered Rover for Asteroids Exploration

This paper proposes an innovative asteroid landing rover, employing a tethered space system, which aims to improve mission success rates and ensure landing safety compared to conventional asteroid detection and landing methods. The irregular shape of the asteroid, resulting in the existence of a complex gravitational field in the surrounding space, which may lead to violent time-varying disturbance Furthermore, the tethered space system exhibits a strong coupling effect, which leads to large variations in tether tension during landing, with serious consequences for the stability of the system. In this paper, a nominal robust model predictive control (RMPC) algorithm is proposed. Through robust state constraints and parameter selection, it ensures recursive feasibility and system stability and has a better robustness to the gravitational field of the asteroid. Considering the strong coupling characteristics caused by the space tether, the tether tension is predictively controlled to ensure the stability during landing and the accuracy of the trajectory tracking. Simulation results show that the system completes the release landing process along the desired trajectory, and also maintains stable tracking of tether length and tension under the complex gravitational field environment of the asteroid.