Notice bibliographique
Résumé
Small satellites flying in formation present a more efficient and affordable way of achieving the same or better performance than a large satellite because of low cost, high density of functionality and a short development cycle. A key technology for achieving mission objectives is the attitude and orbit control system. The overall objective of this dissertation research focuses on developing advanced control strategies and fault tolerant control for satellite formation flying. It is necessary to design and operate the satellite formation flying system to reduce fuel consumption and improve control accuracy. This is a very challenging task due to the nonlinear nature of satellite formation dynamics and the risk of thrusters’ failures and sensors’ faults in the absence of hardware redundancy. A class of nonlinear leader-follower satellite formation flying systems subject to uncertain thrusters’ and sensors’ faults and external J2 disturbances has been studied applying fault detection and identification and second order sliding mode control methodologies. New fault detection and identification and fault tolerant control algorithms were compared with model based fault detection and identification and fault tolerant control algorithms in presence of large initial errors, timevarying external disturbances, and parameter uncertainties. The faults considered were modeled as constant or ramp faults. Numerical results demonstrated the effectiveness of the proposed active fault tolerant control under actuators’ and sensors’ faults. It has been shown that the proposed second order sliding mode control scheme can guarantee local asymptotic stability after system faults. Simulation results confirmed that the suggested control methodologies yield high formation keeping precision and effectiveness for leaderfollower formation flying systems. The tracking errors of the proposed second order sliding mode control, adaptive fuzzy sliding mode control, chattering free sliding mode control and classic sliding mode control resulting from the thruster faults are within 2 m, 4 m, 10 m and 1 m, respectively. The fuel consumption of the proposed second order sliding mode control was the least. It is also necessary to design a fault tolerant satellite attitude control system to reduce fuel consumption and improve control performance accuracy. The proposed fault tolerant attitude control algorithms were based on first order and higher order sliding mode control theory as well as fuzzy logic systems to achieve real time autonomous fault tolerant control. These algorithms were applied to attitude synchronization in both leader-follower formation flying and decentralized formation flying. Attitude synchronization during formation flying was examined considering actuator dynamics while decentralized attitude ynchronization was studied using graph theory with quaternion kinematics. The proposed fault tolerant control algorithm was compared with the existing satellite attitude system controllers in the literature and it was found that the proposed algorithm resulted in three axis attitude stabilization within 0.041◦ in all axes for the fault cases. The reaction wheels’ Coulomb friction, saturations, noise, dead-zones, bias fault and external disturbances are considered. Finally, a nonlinear adaptive fuzzy sliding mode controller was tested using embedded nanosatellite hardware on a frictionless spherical air bearing system. The test results showed attitude errors of 0.8◦ using the proposed controller while a proportional integral derivative controller resulted in 5◦ attitude errors.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».