A flatness-based predictive controller for six-degrees of freedom spacecraft rendezvous

TL;DR

This paper introduces a flatness-based predictive control approach for six-degrees of freedom spacecraft rendezvous, optimizing fuel use and operational constraints while effectively managing disturbances in a complex orbital environment.

Contribution

It develops a novel guidance algorithm combining flatness-based transformation, B-spline discretization, and model predictive control for precise spacecraft rendezvous.

Findings

The method achieves fuel-efficient rendezvous maneuvers.

It effectively handles disturbances and operational constraints.

Numerical simulations validate the approach's effectiveness.

Abstract

This work presents a closed-loop guidance algorithm for six-degrees of freedom spacecraft rendezvous with a passive target flying in an eccentric orbit. The main assumption is that the chaser vehicle has an attitude control system, based on reaction wheels, providing the necessary torque to change its orientation whereas the number of thrusters is arbitrary. The goal is to design fuel optimal maneuvers while satisfying operational constraints and rejecting disturbances. The proposed method is as follows; first, the coupled translational and angular dynamics are transformed to equivalent algebraic relations using the relative translational states transition matrix and the attitude flatness property. Then, a direct transcription method, based on B-splines parameterization and discretization of time continuous constraints, is developed to obtain a tractable static program. Finally, a Model Predictive Controller, based on linearization around the previously computed solution, is considered to handle disturbances. Numerical results are shown and discussed.