Adaptive Super-Twisting Sliding Mode Control Based Hazard Avoidance Guidance for Asteroid Landing

Future asteroid landing and sampling missions will be selected in areas with higher scientific value, such as terrain hazard, and Spacecraft need to have the ability of autonomous hazard avoidance. In this paper, an adaptive super-twisting sliding mode control method is proposed for the asteroid landing with hazard avoidance. The unknown upper bound uncertainty is introduced in the asteroid landing model and the sliding mode surface with artificial potential function gradient is established. Then, the adaptive super-twisting sliding mode controller is designed using quadratic Lyapunov function and the stability of closed-loop system is demonstrated. The simulation results show that the proposed control law has good robustness with unknown upper bound uncertainty, ensures the rapid convergence of the system to the sliding surface and effectively suppresses chattering, and achieves accurate landing and hazard avoidance of the spacecraft.