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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

Design and Development of 75 mm Fixed-Wing Nano Air Vehicle

Pushpangathan, Jinraj V January 2017 (has links) (PDF)
This thesis deals with the design and development of a 75 mm fixed-wing nano-air vehicle (NAV). The NAV is designed to fit inside a cube with each side measuring 75 mm. The range and endurance of the NAV are 300 m and 2-3 minutes, respectively. The high-wing horizontal tailless NAV has a take-off weight of 19.5 g. The battery-powered single propeller NAV has two control surfaces in the form of elevator and rudder. This thesis contains a detailed account of the airfoil selection, selection of the configuration of NAV and the longitudinal, lateral and directional aerodynamic characterization of the NAV. The development of one of the lightweight autopilot hardware which weighs 1.8 g is also given in detail. The development of non-linear equations of motion of NAV including thrust and coupling effects is also discussed. The effects of the gyroscopic coupling and counter torque on the linear dynamics of the NAV are analyzed by conducting a parametric study about the variation of the eigenstructure attributable to the varying degree of coupling in the system matrix of the linear coupled model. A robust simultaneously stabilizing output feedback controller is synthesized for stabilizing the plants of the NAV. The synthesizing of the robust simultaneously stabilizing output feedback controller is based on a frequency-shaped central plant. A new procedure is developed to determine the frequency-shaped central plant utilizing the v-gap metric between the plants, the frequency-shaping of the plants with the pre and post compensators and the robust stabilization theory. An optimization problem is formulated to obtain these compensators. A novel iterative algorithm is developed to acquire the compensators by solving the optimization problem. Thereafter, an iterative algorithm is developed to find an output feedback controller for robust simultaneous stabilization by blending the existing features of robust stability condition of right co-prime uncertainty model of the frequency-shaped central plant, the maximum v-gap metric of the frequency-shaped central plant, H∞ loop-shaping and eigenstructure assignment algorithm for output feedback using the genetic algorithm. The six-degree-of-freedom numerical and hardware-in-loop simulations (HILS) of closed-loop non-linear and linear plants of NAV are performed to assess the performance of the controller and to validate the control algorithm implemented in the autopilot. The airworthiness of the aircraft is tested by conducting flight trials in radio-controlled (RC) mode without including the autopilot. The successful RC flight trial of the NAV indicates airworthiness of the aircraft which aided in freezing the configuration. This is one of the smallest fixed wing aerial vehicle that was successfully flown till date.
2

Prototypage d'un objet volant mimant l'insecte / Prototyping of a Nano air vehicle mimicking flying insect

Bontemps, Alexandre 09 December 2013 (has links)
Ce travail de thèse s'inscrit dans le contexte des drones vise à réaliser à terme un Nano-dispositif volant (Nano Aerial Vehicle) capable d'imiter le vol des insectes. Ce mode de locomotion est privilégié car il présente des caractéristiques très adaptées au vol en milieu confiné. La solution proposée consiste à développer un drone de la taille d'un insecte s'appuyant sur des ailes vibrantes pour se mouvoir et à utiliser les technologies MEMS pour répondre aux problématiques de fabrication et de réduction d'échelle. La réussite d'un tel projet soulève néanmoins de nombreux défis scientifiques et technologiques, en particulier, les aspects aéro-élastiques des ailes et l'autonomie du drone. Pour répondre à ces défis, nous proposons dans un premier temps de mettre en œuvre des concepts comme la résonance et la torsion passive sur des prototypes en polymère (SU-8) réalisés par photolithographie. Dans un second temps, les différents composants de la chaîne de puissance sont optimisés, notamment l'actionneur électromagnétique, la liaison et les ailes de manière à maximiser la force de portance générée. Suite à ces améliorations, nous démontrons de façon expérimentale que le prototype était capable non seulement de reproduire une cinématique complexe mais également de compenser 75% de son poids. / This manuscript reports a work which aims to develop a tiny flying robots inspired by natural flyers. Our main objective is to devise a flying robot mimicking insects in terms of kinematics and scale using MEMS technologies in order to answer the scale challenges: the large-scale manufacturing and the system's small scale. The success this project faces different challenges such as aeroelastic aspects of wings and drone autonomy.In this work we propose the use of original concepts like resonance and passive torsion of the wings which are implemented on all-polymer prototypes obtained using a micromachining SU-8 photoresist process. In order to achieve a better efficiency of the prototype, each element of the energy transduction has been carefully examined and optimized. Especially, the actuation, the transmission and the wings in order to increase the lift. These improvements demonstrate experimentally that the prototype is able to produce a complex kinematic and compensate 75 % of its weight.

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