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Projecte llegit

Títol: Design and construction of a prototype to measure inertia tensors

Estudiants que han llegit aquest projecte:

Director/a: GUTIÉRREZ CABELLO, JORDI

Departament: FIS

Títol: Design and construction of a prototype to measure inertia tensors

Data inici oferta: 03-02-2025     Data finalització oferta: 03-10-2025


Estudis d'assignació del projecte:
    GR ENG SIST AEROESP
Tipus: Individual
 
Lloc de realització: EETAC
 
Segon director/a (UPC): GIL PONS, PILAR
 
Paraules clau:
Microsatellites, attitude determination and control, inertia tensor, torsion pendulum
 
Descripció del contingut i pla d'activitats:
As small satellite missions become more ambitious, the attitude determination and control subsystem (ADCS) becomes increasingly relevant. The accurate operation of ADCS requires precise knowledge of the satellite's dynamic properties, mainly its centre of mass and inertia tensor.
Commercial devices that can measure inertia tensors are very expensive, although their operation and design foundations are relatively simple. In this project, we propose the design of an experimental setup to measure the inertia tensors of CubeSats of up to 6U. We also intend to design and build a prototype to probe different construction alternatives and test the precision with which inertia tensors can be measured. The central idea of the setup consists of a torsion pendulum whose period is related to the inertia moment of the objects placed on that pendulum. Different setups of lasers and mirrors will be used to measure high-precision pendulum periods.
The project will also include the design of an interface to securely tie the satellite to the pendulum and allow different orientations of the satellite to obtain all its inertia tensor components.
The prototype's simplicity and inexpensiveness allow it to be constructed at the EETAC laboratories with a very moderate budget. Once built, it can be used for practical demonstrations of rotational dynamics in classical mechanics lessons (Aerospace and Satellite Engineering degrees), so it must be robust and easy to operate.
 
Overview (resum en anglès):
As small satellite missions become more popular and ambitious, the attitude determination and control subsystem (ADCS) becomes increasingly relevant and plays a more critical role. The accurate operation of ADCS relies heavily on precise knowledge of the satellite's dynamic properties, mainly its centre of mass and inertia tensor. Given the structural complexity of a satellite (particularly due to its internal circuitry, payloads, and other integrated components) analytically computing its inertia tensor becomes extremely challenging. As a result, determining this property through experimental methods emerges as the most practical and reliable approach. The project begins by studying the theoretical background of three-dimensional rotational dynamics and explores the physics behind torsion pendulums, which form the basis of the experimental setup.

Commercial devices that can measure inertia tensors are very expensive, despite their relatively straightforward operating principles and design. Therefore, this project aims to design and build a cost-efficient prototype capable of experimentally measuring the inertia tensors of simple objects. This pendulum prototype will set the basis of a future larger pendulum capable of measuring the inertia tensor of CubeSats. The central idea of the setup consists of a torsion pendulum whose period is related to the inertia moment of the objects placed on that pendulum. An Arduino-based system, using a laser emitter and detector, will be used to measure the periods of oscillation of the pendulum. The project will also include the software needed to perform the measurements and carry out data analysis, including a thorough assessment of uncertainty in the calculations.

The prototype's simplicity and inexpensiveness allow it to be constructed at the EETAC laboratories with a very moderate budget, using accessible materials and resources. Once completed, it can be used as a useful tool for demonstrating rotational dynamics in classical mechanics practical lessons within Aerospace and Satellite Engineering degrees, so it must be robust and easy to operate.

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