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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A decision problem involving the introduction of RTOL aircraft into commercial air transportation systems

Schmitt, Gary Allen 24 July 2012 (has links)
This study is concerned with determining the feasibility of introducing a reduced takeoff and landing (RTOL) aircraft into the national aviation system. In considering this problem, a multiple criteria decision model based on the responses of airline executives was developed to describe the RTOL utilization problem. The exact problem that is considered in this thesis is, for a given set of itineraries, determine the itineraries for which aircraft (RTOL or CTOL, conventional takeoff and landing) are to be assigned such that the amount of fuel used, delay and noise levels are to be minimized. These assignments are subject to aircraft, airport, system and budgetary constraints. A decision-making procedure was formulated to solve the decision problem utilizing an interactive, multicriteria programming procedure. This procedure was developed to consider the use of 0-l decision variables. Two example problems are presented. The air transportation systems considered in the examples include (a) six airports in New York State and (b) five major airport hub areas in the north-eastern section of the United States. / Master of Science
2

Advanced take-off and flight control algorithms for fixed wing unmanned aerial vehicles

De Hart, Ruan Dirk 03 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This thesis presents the development and implementation of a position based kinematic guidance system, the derivation and testing of a Dynamic Pursuit Navigation algorithm and a thorough analysis of an aircraft’s runway interactions, which is used to implement automated take-off of a fixed wing UAV. The analysis of the runway is focussed on the aircraft’s lateral modes. Undercarriage and aerodynamic effects are first analysed individually, after which the combined system is analysed. The various types of feedback control are investigated and the best solution suggested. Supporting controllers are designed and combined to successfully implement autonomous take-off, with acceleration based guidance. A computationally efficient position based kinematic guidance architecture is designed and implemented that allows a large percentage of the flight envelope to be utilised. An airspeed controller that allows for aggressive flight is designed and implemented by applying Feedback Linearisation techniques. A Dynamic Pursuit Navigation algorithm is derived that allows following of a moving ground based object at a constant distance (radius). This algorithm is implemented and verified through non-linear simulation. / AFRIKAANSE OPSOMMING: Hierdie tesis handel oor die ontwikkeling en toepassing van posisie-afhanklike, kinematiese leidings-algoritmes, die ontwikkeling van ’n Dinamiese Volgings-navigasie-algoritme en ’n deeglike analise van die interaksie van ’n lugraam met ’n aanloopbaan sodat outonome opstygprosedure van ’n vastevlerk vliegtuig bewerkstellig kan word. Die bogenoemde analise het gefokus op die laterale modus van ’n vastevlerk vliegtuig en is tweeledig behartig. Die eerste gedeelte het gefokus op die analise van die onderstel, terwyl die lugraam en die aerodinamiese effekte in die tweede gedeelte ondersoek is. Verskillende tipes terugvoerbeheer vir die outonome opstygprosedure is ondersoek om die mees geskikte tegniek te bepaal. Addisionele beheerders, wat deur die versnellingsbeheer gebaseerde opstygprosedure benodig word, is ontwerp. ’n Posisie gebaseerde kinematiese leidingsbeheerstruktuur om ’n groot persentasie van die vlugvermoë te benut, is ontwikkel. Terugvoer linearisering is toegepas om ’n lugspoedbeheerder , wat in staat is tot aggressiewe vlug, te ontwerp. ’n Dinamiese Volgingsnavigasie-algoritme wat in staat is om ’n bewegende grondvoorwerp te volg, is ontwikkel. Hierdie algoritme is geïmplementeer en bevestig deur nie-lineêre simulasie.

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