Global ETD Search

1	Modeling and control of a cabel driven parallel manipulator suspended by a heavy lift airship / Modélisation et commande d'un robot parallèle à câbles suspendus à un dirigeable gros porteur Ben abdallah, Fida 12 July 2019 (has links) A l'heure où le monde entier appelle à développer de nouvelles technologies de transport afin de faire face au défi écologique, des projets de dirigeables gros porteurs permettent de relever ce défi. En outre, les dernières avancées technologiques dans le domaine de l'aérospatiale ont permis de résoudre un certain nombre de problèmes responsables de l'hibernation des grands dirigeables pendant plus d'un demi-siècle. Ceci a donné naissance à de nouveaux types de dirigeables gros porteurs. Dans cette thèse, le modèle dynamique du dirigeable gros porteur est défini afin de concevoir un contrôleur efficient.La particularité du dirigeable présenté est sa capacité de charger et de décharger le fret en vol stationnaire, ce qui permet de réduire l'apport logistique et humain par rapport à des scénarios comportant un atterrissage et permet ainsi l'utilisation de cet engin dans des zones ayant peu ou pas d'infrastructure.Ce dirigeable est muni d'une grue formée par un robot parallèle à câbles (RPC) permettant d'optimiser le chargement et déchargement. Cette phase étant la plus sensible, car la charge suspendue peut osciller dangereusement notamment sous l'effet de bourrasques de vent sur le dirigeable. Nous avons concentré nos efforts dans cette thèse à l'analyse de cette phase critique.Le dirigeable gros porteur sera représenté par un système multi-corps composé de plusieurs corps reliés entre eux par des articulations. Les contributions de la thèse sont présentées en deux parties. Dans la première partie, nous supposons qu'il n'y a pas de couplage inertiel entre le dirigeable et le RPC. Ainsi nos recherches ne concernent que le RPC en tenant compte de la mobilité de la base suspendue par des câbles considérés dans un premier temps comme idéaux, puis les phénomènes d'affaissement et de flexibilité des câbles seront pris en compte. La conception de la commande de ce système doit aussi intégrer une répartition optimale de la tension car les câbles doivent à chaque configuration rester tendus. Dans la deuxième partie, nous abordons l'analyse du système global en considérant l'effet de couplage inertiel entre la charge utile suspendue et le dirigeable. Le modèle dynamique de ce système multicorps formé par le dirigeable et le RPC peut être modélisé comme une interconnexion de sous-systèmes d'ordre inférieur. Nous supposons que le dirigeable gros porteur est un sous-système faiblement couplé. En se basant sur cette hypothèse, un contrôleur décentralisé est proposé permettant de contrôler indépendamment le dirigeable et le RPC. Les résultats des simulations numériques sont présentés et montrent la puissance de ce contrôleur. / In the recent years, researchers have become increasingly interested in the development of radically new and sustainable transportation modes for both passengers and cargo. These challenges have led to study in areas of knowledge that were dormant, such as the potential of using lighter than air aircraft for cargo transportation. The focus of this thesis is the development of a control architecture that can be integrated on autonomous heavy lift airship and thereby enables safe cargo exchange process. Besides, the dynamic model of the heavy lift airship must be clarified before designing a controller. This system makes use of a Cable Driven Parallel Manipulator (CDPM), allowing the airship to load and unload cargo while hovering. The heavy lift airship is a multi-body systems in which multiple rigid bodies are joined together. During loading and unloading process, the transferred cargo can oscillate due toairship maneuvers. On the other hand, the pendulum-like behavior of suspended load canalter the flight characteristics of the airship. The thesis contributions are presented in two parts. In the first part, we assume that there is no inertial coupling between the airship and CDPM. Hence, our researches concern only the CDPM tacking into account the base mobility at first and then the cable sagging phenomena. The control design should integrate an optimal tension distribution since cables must remain in tension.In the second part, we address the analysis of the heavy lift airship considering the coupling effect between the suspended payload and the airship. To describe the dynamics coupling, the basic motion of one subsystem is regarded as an external disturbance input for the other one. Hence, the dynamic model of this multi-body system composed of the airship and the CDPM can be modeled as an interconnection of lower order subsystems. We assume that the heavy lift airship is a weakly coupled subsystems. Based on this assumption, we design a decentralized controller, which makes it possible to control the airship and the CDPM independently. Numerical simulation results are presented and stability analysis are provided to confirm the accuracy of our derivations. Dirigeable gros porteur Heavy lift airship
2	Drive System Design Methodology for a Single Main Rotor Helicopter Bellocchio, Andrew Thomas 21 November 2005 (has links) The transformation of Joint forces to be lighter, more lethal, and capable of deploying from multiple dispersed locations free of prepared landing zones requires a dedicated heavy lift VTOL aircraft capable of rapidly delivering large payloads, such as the 20 to 26 ton Future Combat System, at extended ranges in demanding terrain and environmental conditions. Current estimates for a single main rotor configuration place the design weight over 130,000 pounds with an installed power of approximately 30,000 horsepower. Helicopter drive systems capable of delivering torque of this magnitude succeeded in the Russian Mi-26 helicopters split-torque design and the Boeing VERTOL Heavy Lift Helicopter (HLH) prototypes traditional multi-stage planetary design. The square-cube law and historical trends show that the transmission stage weight varies approximately as the two-thirds power of torque; hence, as the size and weight of the vehicle grows, the transmissions weight becomes an ever-increasing portion of total gross weight. At this scale, optimal gearbox configuration and component design holds great potential to save significant weight and reduce the required installed power. The drive system design methodology creates a set of integrated tools to estimate system weight and rapidly model the preliminary design of drives system components. Tools are provided for gearbox weight estimation and efficiency, gearing, shafting, and cooling. Within the same architecture, the designer may add similar tools to model subcomponents such as support bearings, gearbox housing, freewheeling units, and rotor brakes. Measuring the relationships between key design variables and system performance metrics reveals insight into the performance and behavior of a heavy lift drive system. A parametric study of select design variables is accomplished through an intelligent Design of Experiments that utilizes Response Surface Methodology to build a multivariate regression weight model. The model permits visualization of the design space and assists in optimization of the drive system preliminary design. This methodology is applied to both the Boeing HLH and the Russian Mi-26 main gearboxes. This study applies the drive system design methodology to compare the Mi-26 split-torque gearbox over the Boeing HLH multi-stage planetary gearbox in a single main rotor heavy lift helicopter. Split torque Weight estimate Shaft Gear Transmission Helicopter Heavy lift Drive system
3	A plm implementation for aerospace systems engineering-conceptual rotorcraft design Hart, Peter Bartholomew 08 April 2009 (has links) The thesis will discuss the Systems Engineering phase of an original Conceptual Design Engineering Methodology for Aerospace Engineering-Vehicle Synthesis. This iterative phase is shown to benefit from digitization of Integrated Product&Process Design (IPPD) activities, through the application of Product Lifecycle Management (PLM) technologies. Requirements analysis through the use of Quality Function Deployment (QFD) and 7 MaP tools is explored as an illustration. A "Requirements Data Manager" (RDM) is used to show the ability to reduce the time and cost to design for both new and legacy/derivative designs. Here the COTS tool Teamcenter Systems Engineering (TCSE) is used as the RDM. The utility of the new methodology is explored through consideration of a legacy RFP based vehicle design proposal and associated aerospace engineering. The 2001 American Helicopter Society (AHS) 18th Student Design Competition RFP is considered as a starting point for the Systems Engineering phase. A Conceptual Design Engineering activity was conducted in 2000/2001 by Graduate students (including the author) in Rotorcraft Engineering at the Daniel Guggenheim School of Aerospace Engineering at the Georgia Institute of Technology, Atlanta GA. This resulted in the "Kingfisher" vehicle design, an advanced search and rescue rotorcraft capable of performing the "Perfect Storm" mission, from the movie of the same name. The associated requirements, architectures, and work breakdown structure data sets for the Kingfisher are used to relate the capabilities of the proposed Integrated Digital Environment (IDE). The IDE is discussed as a repository for legacy knowledge capture, management, and design template creation. A primary thesis theme is to promote the automation of the up-front conceptual definition of complex systems, specifically aerospace vehicles, while anticipating downstream preliminary and full spectrum lifecycle design activities. The thesis forms a basis for additional discussions of PLM tool integration across the engineering, manufacturing, MRO and EOL lifecycle phases to support business management processes. Teamcenter systems engineering Teamcenter community Teamcenter unified Teamcenter engineering Teamcenter manufacturing CATIA V5 Rotorcraft design Boeing AHS Joint heavy lift VPLM MBOM EBOM Product change control Product definition Configuration management Product structure architecture Design engineering Aerospace engineering System engineering PLM CIE IDE SE Affordability Cost savings Executive helicopter Joint chiefs of staff Marine CAE CAD CAM CAA MDO RSM DOE Consulting Engineering management Perfect storm Engineering software Requirements data management CATIA V4 NX Engineering communications RFP Digitization Air Force Navy Army BAMS FIPER ACSYNT Sikorsky Bell Georgia Tech Engineering methodology Requirements engineering System engineering Search Rescue IDE Integrated digital environment Kingfisher Search and rescue Helicopter Helicopter engineering QFD Legacy design IPPD Quality engineering Defense systems acquisition Coast Guard Decision support systems Rotors (Helicopters) Design Concurrent engineering

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