Observer-Based Fault-Tolerant Spacecraft Attitude Tracking Using Sequential Lyapunov Analyses

TL;DR

This paper presents an observer-based control approach for spacecraft attitude tracking that ensures robustness against actuator faults and uncertainties, with a method to predict steady-state performance bounds.

Contribution

It introduces a sequential Lyapunov analysis method to derive tighter steady-state error bounds and integrates it with a sliding mode controller using observer estimates.

Findings

Ensures robust stability with bounded estimation errors.

Provides a systematic way to predict and tune steady-state tracking performance.

Demonstrates effectiveness through numerical simulations.

Abstract

The spacecraft attitude tracking problem is addressed with actuator faults and uncertainties among inertias, external disturbances, and, in particular, state estimates. A continuous sliding mode attitude controller is designed using attitude and angular velocity estimates from an arbitrary stable stand-alone observer. Rigorous analysis shows that the controller ensures robust stability of the entire closed-loop system as long as the observer yields state estimates with uniformly ultimately bounded estimation errors. In addition, a sequential Lyapunov analysis is utilized to obtain a convergent sequence of analytical, successively tighter upper bounds on the steady-state tracking error. Therefore, our results can be used to predict steady-state performance bounds given selected gains or facilitate gain selection given steady-state performance bounds. Numerical examples demonstrate the utility of the proposed theory.