Development of a robotic system for CubeSat Attitude Determination and Control System ground tests Irina Gavrilovich To cite this version: Irina Gavrilovich. Development of a robotic system for CubeSat Attitude Determination and Control System ground tests. Automatic. Université Montpellier, 2016. English. NNT : 2016MONTT329. tel-01816985 HAL Id: tel-01816985 https://tel.archives-ouvertes.fr/tel-01816985 Submitted on 15 Jun 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. [Tapez une citation prise dans le document ou la synthèse d'un passage intéressant. Vous pouvez placer la Délivré par Université de Montpellier zone de texte n'importe où dans le document. Utilisez l'onglet Outils de zone de texte pour modifier la mise en Préparée au sein de l’école doctorale forme de la zone de texte de la citation.] Information, Structures, Systèmes (I2S) Et de l’unité de recherche Laboratoire d’Informatique, de Robotique et de Microélectronique de Montpellier (LIRMM) Spécialité : SYAM Présentée par Irina GAVRILOVICH DEVELOPMENT OF A ROBOTIC SYSTEM FOR CUBESAT ATTITUDE DETERMINATION AND CONTROL SYSTEM GROUND TESTS Soutenue le 14 Décembre 2016 devant le jury composé de Laurent Dusseau Professeur UM, Centre Spatial Universitaire Président François Pierrot DR CNRS LIRMM Directeur Sébastien Krut CR CNRS LIRMM Encadrant Marc Gouttefarde CR CNRS LIRMM Encadrant Gabriel Abba Professeur Université de Lorraine Rapporteur Paolo Tortora Assoc. Prof. Université de Bologne Rapporteur Sabrina Corpino Assist. Prof Ecole Polytechnique de Turin Examinateur RESUME Après le lancement du premier satellite artificiel en 1957, l'évolution de diverses technologies a favorisé la miniaturisation des satellites. En 1999, le développement des nano-satellites modulaires appelés CubeSats, qui ont la forme d'un cube d'un décimètre de côté et une masse de 1 kg à 10 kg, a été initié par un effort commun de l'Université polytechnique de Californie et de l'Université de Stanford. Depuis lors, grâce à l’utilisation de composants électroniques standards à faible coût, les CubeSats se sont largement répandus. Au cours des dernières années, le nombre de CubeSats lancés a régulièrement augmenté, mais moins de la moitié des missions ont atteint leurs objectifs. L'analyse des défaillances des CubeSats montre que la cause la plus évidente est le manque d ’essais adéquats des composants du système ou du système au complet. Parmi les tâches particulièrement difficiles, on compte les essais « hardware-in-the-loop » (HIL) du système de contrôle d'attitude et d'orbite (SCAO) d’un CubeSat. Un système dédié à ces essais doit permettre des simulations fiables de l'environnement spatial et des mouvements réalistes des CubeSats. La façon la plus appropriée d’obtenir de telles conditions d’essai repose sur l’utilisation d’un coussin d'air. Toutefois, les mouvements du satellite sont alors contraints par les limites géométriques, qui sont inhérentes aux coussins d'air. De plus, après 15 années de développements de CubeSats, la liste des systèmes proposés pour tester leur SCAO reste très limitée. Aussi, cette thèse est consacrée à l ’étude et à l a conception d’un système robotique innovant pour des essais HIL du SCAO d’un CubeSat . La nouveauté principale du système d'essai proposé est l’usage de quatre coussins d'air au lieu d'un seul et l’emploi d’ un robot manipulateur. Ce système doit permettre des mouvements non contraints du CubeSat. Outre la conception du système d'essai, cette thèse porte sur les questions liées: (i) à la détermination de l'orientation d’un CubeSat au moyen de mesures sans contact; (ii) au comportement de l’assemblage des coussins d'air; (iii) à l'équilibrage des masses du système. Afin de vérifier la faisabilité de la conception proposée, un prototype du système d'essai a été développé et testé. Plusieurs modifications destinées à en simplifier la structure et à réduire le temps de fabrication ont été effectuées. Un robot Adept Viper s650 est notamment utilisé à la place d'un mécanisme sphérique spécifiquement conçu. Une stratégie de commande est proposée dans le but d’assurer un mouvement adéquat du robot qui doit suivre les rotations du CubeSat. Finalement, les résultats obtenus sont présentés et une évaluation globale du système d'essai est discutée. ABSTRACT After the launch of the first artificial Earth satellite in 1957, the evolution of various technologies has fostered the miniaturization of satellites. In 1999, the development of standardized modular satellites with masses limited to a few kilograms, called CubeSats, was initiated by a joint effort of California Polytechnic State University and Stanford University. Since then, CubeSats became a widespread and significant trend, due to a number of available off-the-shelf low cost components. In last years, the number of launched CubeSats constantly grows, but less than half of all CubeSat missions achieved their goals (either partly or completely). The analysis of these failures shows that the most evident cause is a lack of proper component-level and system- level CubeSat testing. An especially challenging task is Hardware-In-the-Loop (HIL) tests of the Attitude Determination and Control System (ADCS). A system devoted to these tests shall offer reliable simulations of the space environment and allow realistic CubeSat motions. The most relevant approach to provide a satellite with such test conditions consists in using air bearing platforms. However, the possible satellite motions are strictly constrained because of geometrical limitations, which are inherent in the air bearing platforms. Despite 15 years of CubeSat history, the list of the air bearing platforms suitable for CubeSat ADCS test is very limited. This thesis is devoted to the design and development of an air bearing testbed for CubeSat ADCS HIL testing. The main novelty of the proposed testbed design consists in using four air bearings instead of one and in utilizing a robotic arm, which allows potentially unconstrained CubeSat motions. Besides the testbed design principle, this thesis deals with the related issues of the determination of the CubeSat orientation by means of contactless measurements, and of the behavior of the air bearings, as well as with the need of a mass balancing method. In order to verify the feasibility of the proposed design, a prototype of the testbed is developed and tested. Several modifications aimed at simplifying the structure and at shortening the fabrication timeline have been made. For this reason, the Adept Viper s650 robot is involved in place of a custom-designed 4DoF robotic arm. A control strategy is proposed in order to provide the robot with a proper motion to follow the CubeSat orientation. Finally, the obtained results are presented and the overall assessment of the proposed testbed is put into perspective. ACKNOWLEDGEMENTS First and foremost I would like to acknowledge my thesis director, Prof. François Pierrot, who accepted me as a Ph.D student at the LIRMM and has believed in my research. I would like to express my sincere gratitude to my thesis advisors, Sébastien Krut and Marc Gouttefarde, for they continuous support and guidance during these 3 years. Sébastien was the first person who welcomed me at the LIRMM and since then he has always provided me with encouragement and valuable advices whenever it was needed. I am very grateful to him for knowledge he has shared with me and all time he has spent to facilitate my habituation to the new domain. I appreciate all his contributions of energy, ideas and funding to make my research productive. Besides that he has helped me identify my professional strengths and accept them. I would like to thank Marc for his assistant with all my writings and his patience to correct them. I dare to believe that all his efforts to improve my writing skills were not in vain. They both, Sébastien and Marc, have taught me, equally consciously and unconsciously, how good research is done. My research would not have been possible without support of the Montpellier-Nîmes University Space Center (CSU) and funding from the Van Allen Foundation. I wish to thank these organizations and personally Prof. Laurent Dusseau and Prof. Frédéric Saigné for giving me the invaluable opportunity to fulfill myself as a researcher, to present results of my work on several conferences and to write this thesis. I would like to thank my colleagues from the Robotics Department for their readiness to help and to share their experience. Especially, I am grateful to Samah Shayya for his short in time, but very informative introduction to the Simulink Real-Time and Speedgoat target, and to Alonso Sanches who has aided me deal with the Viper robot and provided his C++ code that saved me a good half-year of work. Let me also mention my friends who have been responsible for the entertainment aspects of my life during these years: Nastya, Artem, Andrey, Roman, Viyas. I appreciate their support, advices and all wonderful moments we have spent together, and I hope our friendship will last long despite distances and boarders. I would like to express my deepest gratitude to my family that was the most supportive and motivating team I could ever imagine. I warmly thank my mom who bravely let me go in my big journey abroad and has always selflessly supported me in all my pursuits. And I especially thank my beloved husband who has always been on my side during these years.