Faculté des Sciences appliquées
Faculté des Sciences appliquées

Master thesis and internship[BR]- Master's Thesis : Identification and analysis of vibration sources in a micro-CMG[BR]- Internship (linked to master's thesis)

Noiset, Guillaume ULiège
Promotor(s) : Kerschen, Gaëtan ULiège
Date of defense : 25-Jun-2020/26-Jun-2020 • Permalink :
Title : Master thesis and internship[BR]- Master's Thesis : Identification and analysis of vibration sources in a micro-CMG[BR]- Internship (linked to master's thesis)
Translated title : [fr] Identification et analyse des sources de vibrations au sein d'un micro-CMG
Author : Noiset, Guillaume ULiège
Date of defense  : 25-Jun-2020/26-Jun-2020
Advisor(s) : Kerschen, Gaëtan ULiège
Committee's member(s) : Bruls, Olivier ULiège
Collette, Christophe ULiège
Demonty, Julien 
Language : English
Number of pages : 54
Keywords : [en] Micro-CMG
[en] Vibrations
[en] Experimentation
Discipline(s) : Engineering, computing & technology > Aerospace & aeronautics engineering
Institution(s) : Université de Liège, Liège, Belgique
Degree: Master en ingénieur civil en aérospatiale, à finalité spécialisée en "aerospace engineering"
Faculty: Master thesis of the Faculté des Sciences appliquées


[en] Control moment gyroscopes are efficient systems of attitude control for satellites. As every rotating assembly, they produce undesirable vibrations in spacecrafts. Instead of isolating the satellite from these systems to prevent the spread of the perturbations, it is important to first decrease the generation of vibrations itself. The main vibration sources have been identified as the balance of the flywheel, the impurities in the bearings and the motor ripple.

The key parameters influencing the generation of the vibrations explored in this work are the balance of the wheel, the preload, the contact angle and the quality of the bearings. An experimental set-up is then designed to highlight their impact on the frequency spectrum: an aluminium structure embracing a bearing pair holds the flywheel concentric with the axis of the motor. To study all the key parameters, the set-ups use several pairs of bearings and wheels. By adapting the rotation speeds, the flywheel, the bearings and the preload, multiple test plans are elaborated to compare the influence of the various parameters.

Preliminary studies prove that the structure is fit to sustain the applied loads. Further, they predict an optima speed of 4,000 RPM for an ideal lubricant layer in the bearings, reducing the friction while providing good wear protection. A last study predicts a maximum rotation speed of about 5,000 RPM, due to the grease generating high friction, while the driving torque is limited.

The different protocols established in this work aim at highlighting a decrease of the vibration generation through a lower preload, a balanced wheel and high quality bearings protected from external bodies.



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  • Noiset, Guillaume ULiège Université de Liège > Master ingé. civ. aérospat., à fin.


Committee's member(s)

  • Bruls, Olivier ULiège Université de Liège - ULiège > Département d'aérospatiale et mécanique > Laboratoire des Systèmes Multicorps et Mécatroniques
    ORBi View his publications on ORBi
  • Collette, Christophe ULiège Université de Liège - ULiège > Département d'aérospatiale et mécanique > Active aerospace struct. and adv. mecha. systems
    ORBi View his publications on ORBi
  • Demonty, Julien VEOWARE
  • Total number of views 26
  • Total number of downloads 0

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