Modelling, Dynamic Analysis and Robotic Control Strategies for the Deorbiting Operations of the ESA Satellite Envisat

Abstract

This master thesis was developed in the context of the e.Deorbit project. Firstly, the force for the deorbiting manoeuvre was analysed in order to find a profile that does not induce detachment between the Servicer module and Envisat when a clamping mechanism is not considered. Then, the proposed configurations with a four points clamping connection and a clamping to the payload adapter of Envisat were modelled and analysed. A special focus was posed on the flexibility of the 16 meter long solar panel of Envisat: this was considered divided in rigid sections and flexible joints. Additionally, the detumbling manoeuvre was analysed in order to validate the feasibility of this manoeuvre with the robotic arm grasped to the target. The main part of the work was to analyse a closed loop configuration: the aim was to reduce the oscillation of the solar panel during the deorbiting operations. In order to simulate that configuration, a the Loop Joint method by Featherstone was implemented and included in the SpaceDyn library. After testing the written algorithms, a damping control was simulated.