Modelling, Identification and Validation of Flexible Appendages for Satellite Applications to In-Orbit Assembly

November 20, 2025

The evolution of space systems toward larger, modular, and reconfigurable structures has introduced significant challenges in the modelling, identification and control of flexible appendages, commonly represented by cantilever beams. However, most studies focus on masses attached at its free tip, limiting applicability to scenarios where masses are attached at arbitrary positions or structures that evolve during assembly. This thesis investigates the dynamics of a cantilever beam with a mass positioned arbitrarily and its interaction with a hub simulating a spacecraft platform, providing both experimental and analytical insights. First, the mechanical and dynamic properties, such as critical load, natural frequencies and damping ratio of the beam are characterized, ensuring suitability for subsequent experiments. A series of experimental tests are then performed to evaluate the beam’s dynamic response under various mass positions and then comparing those results with analytical and finite element models. These experiments emphasize the influence of intermediate masses and validate the accuracy of the proposed modelling approaches. Subsequently, a linear dynamic model of the coupled hub-beam system is developed and validated using experimental data from the In-Orbit Assembly of Large Antennas (IOANT) project, capturing the rigid-flexible interactions and configurations relevant to on-orbit assembly scenarios. This work contributes with a validated methodology for modelling and experimentally characterizing cantilever beams with arbitrary mass distributions, providing essential data for robust design of flexible structures, useful for both Mechanical Engineering and Guidance, Navigation and Control (GNC) strategies.

Authors in the community:

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  M

  Mariana Roldão Ferreira

  ist1110894

Supervisors of this institution:

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  A

  Aurélio Lima Araújo

  ist62256

mechanical-engineering - Mechanical engineering

eng - English

Instituto Superior Técnico