Attitude Analysis and Robust Adaptive Backstepping Sliding Mode Control of Spacecrafts Orbiting Irregular Asteroids

Chunhui Liang,Yuanchun Li

doi:10.1155/2014/367163

Abstract

Attitude stability analysis and robust control algorithms for spacecrafts orbiting irregular asteroids are investigated in the presence of model uncertainties and external disturbances. Rigid spacecraft nonlinear attitude models are considered and detailed attitude stability analysis of spacecraft subjected to the gravity gradient torque in an irregular central gravity field is included in retrograde orbits and direct orbits using linearized system model. The robust adaptive backstepping sliding mode control laws are designed to make the attitude of the spacecrafts stabilized and responded accurately to the expectation in the presence of disturbances and parametric uncertainties. Numerical simulations are included to illustrate the spacecraft performance obtained using the proposed control laws.

Highlights

SMALL bodies including mainly asteroids and comets are studied by scientists because of the insight they can give into the history of the solar system
Wang and Xu find that the attitude stability domain is modified significantly due to the significantly nonspherical shape and rapid rotation of the asteroid, and attitude stability subjected to the disturbance of the gravity gradient torque is generalized to a rigid spacecraft on a stationary orbit around an asteroid [10, 11]
This paper has focused on the attitude dynamics and effect control algorithms for spacecraft orbiting rotating asteroids

Summary

Introduction

SMALL bodies including mainly asteroids and comets are studied by scientists because of the insight they can give into the history of the solar system. An asteroid’s irregular shape, mass distribution, and the state of its rotation (rapid or slow) have significant effects on the evolution of spacecraft orbit and attitude motion Scheeres and his coworkers have made a large number of contributions to the study of orbital motion about asteroids [6,7,8,9]. The robust adaptive backstepping sliding mode control laws are proposed to compensate the uncertainties and perturbations and make the attitude angles decay and reach the null state, which ensure orbiting motion and space mission.

System Equations of Motion

Analysis of Motion for Orbiting Circular Orbits

Controller Design

Conclusions