On-Orbit Servicing Satellite Docking Mechanism Modeling and Simulation

Abstract: Docking mechanism of two spacecraft is considered as one of the main challenging aspects of an on-orbit servicing mission. This thesis presents the modeling, analysis and software simulation of one of the docking mechanisms called "probe and drogue". The aim of this thesis is to model the docking mechanism, simulate the docking process and use the results as a reference for the Hardware-In-the-Loop simulation (HIL) of the docking mechanism, in order to verify and validate it. Modeling of the two spacecraft, docking mechanism and the contact dynamics are the most challenging parts of this thesis. The spacecraft motion's modeling is done using Newton-Euler equations, with consideration of the homogeneous transformations of the different coordinate frames. Contact dynamics modeling included the Hertz dynamics, different types of damping models and a modified Coulomb's friction model. Simulink/ Matlab 2013b are used to build two models, one for numerical analysis of the model and another one for the HIL simulation. Results are analyzed in Matlab and visualized using the 3D visualization program that is built within the scope of this thesis. The results are then used as a guide for the requirements of the robotic hardware that will carry out the HIL simulation. Also, two different robotics hardware are proposed in this thesis to carry out the HIL simulation. The work has a lot of aspects in common with the satellite of the German Space Agency (DLR) called, "DEutsche Orbitale Servicing Mission" (DEOS). This work took place in Friedrichshafen/Germany at the facilities of Airbus Defence and Space (the prime contractor of DEOS) in collaboration with Würzburg university in Germany and Luleå university of technology in Sweden.