Finite-Time Spacecraft’s Soft Landing on Asteroids Using PD and Nonsingular Terminal Sliding Mode Control

Abstract

This paper presents a continuous control law of probe, which consists of PD (proportional-derivative) controller and nonsingular terminal sliding mode controller for probe descending and landing phases, respectively, in the case of the asteroid irregular shape and low gravity. The probe dynamic model is deduced in the landing site coordinate system firstly. Then the reference trajectory based on optimal polynomial in open-loop state is designed, with the suboptimal fuel consumption. Taking into account different characteristics of phases, PD controller and nonsingular terminal sliding mode controller can be employed in the descending phase and the landing phase, respectively, to track the designed reference trajectory. The controller which used the corresponding control methods can meet the motion characteristics and requirements of each stage. Finally simulation experiments are carried out to demonstrate the effectiveness of the proposed method, which can ensure the safe landing of probe and achieve continuous control.

Robust Linear Quadratic Regulator via Sliding Mode Guidance for Spacecraft Orbiting a Tumbling Asteroid

“…Furfaro et al [6] investigated a novel closed-loop autonomous guidance law based on multiple sliding surfaces for the soft landing of the spacecraft on the designated point on the asteroid. Liu et al [7] presented orbital control law for the spacecraft, which consists of PD controller and a nonsingular terminal sliding mode controller, to track the soft landing trajectory. Guelman [8] investigated a simple three-dimensional guidance law for the orbit transfer to a quasi-circular orbit about a rotating small celestial body using continuous thrust.…”

A Computationally Inexpensive Optimal Guidance via Radial-Basis-Function Neural Network for Autonomous Soft Landing on Asteroids

“…Based on the autonomous navigation system using the feature tracking technology, Huang et al [ 2 ] planned desired descent landing trajectories of the spacecraft as the three power polynomial form with the initial and terminal constraint, and then applied a variable structure control to track the trajectory. This reference trajectory guidance based on the three power polynomial technology was widely applied [ 3 – 5 ]. Roberto Furfaro et al [ 6 ] developed a novel closed-loop autonomous guidance law based on multiple sliding surfaces for the soft landing of the spacecraft on the designated point on the asteroid.…”