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CEAS EuroGNC 2026

Tractor-Beam: An Experimental Testbed for Control of In-Orbit Service Systems with Varying Flexible Dynamics and Inertia
Jose F. Briz GNC Engineer, GMV Innovating Solutions, Madrid, Spain.
Eduardo de Brito Software Engineer, GMV Innovating Solutions, Lisbon, Portugal. Instituto Superior Técnico (IST), Lisbon, Portugal.
Marco Rubaga Systems Engineer, GMV Innovating Solutions, Lisbon, Portugal. Delft University of Technology, Delft, The Netherlands.
Mariana Ferreira Structural Engineer, GMV Innovating Solutions, Lisbon, Portugal. Instituto Superior Técnico, Lisbon, Portugal.
Luís Ferreira GNC Engineer, GMV Innovating Solutions, Lisbon, Portugal. Instituto Superior Técnico, Lisbon, Portugal.
Hugo Pereira GNC Engineer, GMV Innovating Solutions, Lisbon, Portugal.
Diogo Oliveira Software Engineer, GMV Innovating Solutions, Lisbon, Portugal.
Iñaki Colmenarejo Hardware Technician, GMV Innovating Solutions, Madrid, Spain.
Nuno Paulino Project Manager, GMV Innovating Solutions, Lisbon, Portugal.
Pedro Lourenço Section Head Advanced Guidance & Control, GMV Innovating Solutions, Lisbon, Portugal.
Valentin Preda Technical Officer, ESTEC, Noordwijk, The Netherlands.
Abstract:
In the last few years, In-Orbit Servicing, Assembly and Manufacturing (ISAM) has become one of the main and most discussed topics in space operations, ensuring increased flexibility, scalability and allowing mission concepts not feasible with current approaches based on ground assembly. From the point of view of Guidance, Navigation and Control (GNC), one of the main challenges of ISAM operations is accurate control of systems whose properties change over time or are not known precisely, due to recurring operations of docking, separation, assembly and disassembly. Here, we introduce the TRACTOR-beam experimental test rig, used in rapid prototyping and testing for research in control and system identification with time-varying bending modes, inertia properties or additional effects which can be added in a modular fashion. The setup is comprised of a 1 Degree of Freedom (DoF) rotating platform on a low friction support, actuated with a reaction wheel, and it combines a central hub, a flexible appendage, and a robotic walker that moves along the appendage. The latter allows for variation of inertia and bending properties during the experiments. The setup realizes a ground surrogate experiment which captures the problems and challenges faced during ISAM, with low friction attitude dynamics, the robotic walker changing the system properties by moving on top of the flexible beam, and a space-representative set of sensors and actuators. The TRACTOR platform follows a modular architecture which supports distributed intelligence and modular expansion. A digital twin of the test setup was developed in MATLAB/Simulink, replicating the main dynamic effects, sensors and actuators. The wireless communication interfaces with MATLAB/Simulink provide a streamlined deployment of OBSW and management of the experiment, and an end-to-end validation chain enabling rapid prototyping and testing cycle. The paper provides a description of the test setup, digital twin with its SW interface, and experimental preliminary results in closed-loop, as well as system identification for different mass configurations.
Keywords: ISAM; In-Orbit Assembly; AOCS; Surrogate Experiments; Flexible Structures; Attitude Control; Hardware-in-the-loop; HIL (Hardware-in-the-loop); Validation
 View PDF CEAS-GNC-2026-062 doi: 10.82124/CEAS-GNC-2026-062


Jose F. Briz, Eduardo de Brito, Marco Rubaga, Mariana Ferreira, Luís Ferreira, Hugo Pereira, Diogo Oliveira, Iñaki Colmenarejo, Nuno Paulino, Pedro Lourenço, Valentin Preda: Tractor-Beam: An Experimental Testbed for Control of In-Orbit Service Systems with Varying Flexible Dynamics and Inertia. Proceedings of the 2026 CEAS EuroGNC conference. Madrid, Spain. May 2026. doi: 10.82124/CEAS-GNC-2026-062.
BibTeX entry (UTF-8):

@Incollection{CEAS-GNC-2026-062,
    author = {Briz, Jose F. and de Brito, Eduardo and Rubaga, Marco and Ferreira, Mariana and Ferreira, Luís and Pereira, Hugo and Oliveira, Diogo and Colmenarejo, Iñaki and Paulino, Nuno and Lourenço, Pedro and Preda, Valentin},
    title = {Tractor-Beam: An Experimental Testbed for Control of In-Orbit Service Systems with Varying Flexible Dynamics and Inertia},
    booktitle = {Proceedings of the 2026 {CEAS EuroGNC} conference},
    address = {Madrid, Spain},
    month = may,
    year = {2026},
    doi = {10.82124/CEAS-GNC-2026-062}
}