Center-of-Mass and Attitude Control of an Orbital Manipulator: A Novel Control Strategy

Abstract

In this work, we propose a novel control strategy for the displacement of an orbital manipulator equipped with a thruster module at its end-effector. In contrast to the use of base-mounted thrusters, which often leads to allocation problems and fuel inefficiencies, the proposed approach achieves center-of-mass (CoM) maneuvers using only the end-effector thruster. The main challenge is to translate the CoM while maintaining the satellite base attitude fixed and avoiding angular momentum generation. The strategy consists of two phases: first, the manipulator orients the thruster while maintaining the base orientation via reaction wheels; second, the thruster generates an external force required to relocate the CoM while conserving attitude. This coordinated use of manipulator motion and end-effector actuation enables effective CoM control under attitude constraints. The proposed controller is validated with multi-body dynamic simulations and an Hardware-in-the-Loop robotic facility.