Control analysis for a contactless de-tumbling method based on eddy currents: problem definition and approximate proposed solutions

摘要

Existing active debris removal (ADR) methods that require physical contact with the target have applicability limitations depending on the maximum angular momentum that can be absorbed. Therefore, a de-tumbling phase prior to the capturing phase may be necessary. The aim of this article is to present the on-going work on the control module of a contactless de-tumbling subsystem based on eddy currents ('Eddy Brake'). This research is being carried out in the framework of the Agora mission (Active Grabbing & Orbital Removal of Ariane), which employs a robotic spacecraft concept to demonstrate technologies to autonomously de-tumble, capture and de-orbit an Ariane rocket body. The article first presents the 'Eddy Brake' method and the Guidance, Navigation and Control (GNC) architecture of a chaser spacecraft. Furthermore, the linear and rotational dynamics based on the Magnetic Tensor Theory (MTT) are explained. Then, a control strategy is presented to keep a constant relative distance between the two objects and a suitable relative pointing of the coil towards the target object. A simplified analytical solution for the control of the two objects in the 2D problem is presented and the stability of the system in the vicinity of a stable asymptotic state is analysed. Finally, two case studies are presented on the Ariane-4 H10 and Ariane-5 EPS upper stages.