Six-DOF Spacecraft Dynamics Simulator For Testing Translation and Attitude Control

TL;DR

This paper introduces a control method for a spacecraft simulator that accurately replicates the motion of a free-floating spacecraft in a laboratory setting, enabling zero-g emulation for testing purposes.

Contribution

It presents a novel control approach combining motion and force feedback to emulate spacecraft dynamics, including flexible appendages, in a ground-based simulator.

Findings

System remains stable under certain inertial conditions

Calibration and sensor noise sensitivity are analyzed

Method enables accurate zero-g spacecraft simulation

Abstract

This paper presents a method to control a manipulator system grasping a rigid-body payload so that the motion of the combined system in consequence of externally applied forces to be the same as another free-floating rigid-body (with different inertial properties). This allows zero-g emulation of a scaled spacecraft prototype under the test in a 1-g laboratory environment. The controller consisting of motion feedback and force/moment feedback adjusts the motion of the test spacecraft so as to match that of the flight spacecraft, even if the latter has flexible appendages (such as solar panels) and the former is rigid. The stability of the overall system is analytically investigated, and the results show that the system remains stable provided that the inertial properties of two spacecraft are different and that an upperbound on the norm of the inertia ratio of the payload to manipulator is respected. Important practical issues such as calibration and sensitivity analysis to sensor noise and quantization are also presented.