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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

Pitch and Altitude Control of an Unmanned Airship with Sliding Gondola

Alsayed, Ahmad January 2017 (has links)
An unmanned airship has an ability of heavy lifting capabilities, low environmental footprint, and long endurance, however, the unmanned airships are faced challenges linked to the maneuverability during landing and the reliability of control. In this thesis, the six degrees of freedom equations of motion of a miniature unmanned airship with a sliding gondola have been derived. Then the model was implemented and simulated in the Matlab/Simulink. The wind disturbance was also implemented in the model. The model was then trimmed and linearized in to obtain pitch and altitude PID controllers using the gondola position as an input. Both controllers were simulated with different reference inputs and disturbances. The experimental platform, hardware, sensors and graphical user interface of the ground station were described. Then, experimental flight tests were performed to evaluate the pitch controller.
2

Assessing the cost competitiveness of a cargo airship for freight re-supply in isolated regions in northern Canada

Adaman, Matthew 07 October 2013 (has links)
The East Side of Lake Winnipeg, North Western Ontario, and the Kivalliq region in Central Nunavut are selected as case regions in which the cost competitiveness of the cargo airship can be estimated. Data from the North West Company that describes freight movements and associated costs are used in this comparative analysis. A cargo airship developer provided operating cost data that are operationalized using the North West Company’s data. Results show that using a cargo airship could produce annual transportation cost savings of between 12.5% and 38.3% per year. These results are similar across all three regions and vary based on the scenario modelled within each case region. The findings from this research are subject to the assumptions that the operating cost model described by the cargo airship developer is accurate, and is limited in scope because it focuses solely on one company’s shipping needs in select regions.
3

Assessing the cost competitiveness of a cargo airship for freight re-supply in isolated regions in northern Canada

Adaman, Matthew 07 October 2013 (has links)
The East Side of Lake Winnipeg, North Western Ontario, and the Kivalliq region in Central Nunavut are selected as case regions in which the cost competitiveness of the cargo airship can be estimated. Data from the North West Company that describes freight movements and associated costs are used in this comparative analysis. A cargo airship developer provided operating cost data that are operationalized using the North West Company’s data. Results show that using a cargo airship could produce annual transportation cost savings of between 12.5% and 38.3% per year. These results are similar across all three regions and vary based on the scenario modelled within each case region. The findings from this research are subject to the assumptions that the operating cost model described by the cargo airship developer is accurate, and is limited in scope because it focuses solely on one company’s shipping needs in select regions.
4

The UAV logger as a potential alternative for timber transportation in the Canadian boreal forest

Wychreschuk, Alena 14 August 2012 (has links)
The Canadian boreal forest has substantial natural resources located in remote isolated areas that are of economic interest. Requirements of the log extraction operation are to minimize impact on the ecosystem and its inhabitants. Transportation is one of the largest direct costs of forestry operations and many potential harvest areas are left untouched because of the high costs to build and maintain logging roads and water crossings. Alternatives to the traditional surface transportation system could benefit the industry, the residents and the ecosystem. The economics of a Lighter-Than-Air UAV Logger concept for log transportation is compared to the current truck and road build option using a cost comparison model and three harvest area case studies. At the engineered price estimate of $4.1 million, the results suggest that the UAV Logger is an uneconomic transportation alternative in the boreal forest at current product prices and supply availability. Conditions that favour the UAV Logger as a competitive economic alternative include small harvest volumes and high road build costs.
5

The UAV logger as a potential alternative for timber transportation in the Canadian boreal forest

Wychreschuk, Alena 14 August 2012 (has links)
The Canadian boreal forest has substantial natural resources located in remote isolated areas that are of economic interest. Requirements of the log extraction operation are to minimize impact on the ecosystem and its inhabitants. Transportation is one of the largest direct costs of forestry operations and many potential harvest areas are left untouched because of the high costs to build and maintain logging roads and water crossings. Alternatives to the traditional surface transportation system could benefit the industry, the residents and the ecosystem. The economics of a Lighter-Than-Air UAV Logger concept for log transportation is compared to the current truck and road build option using a cost comparison model and three harvest area case studies. At the engineered price estimate of $4.1 million, the results suggest that the UAV Logger is an uneconomic transportation alternative in the boreal forest at current product prices and supply availability. Conditions that favour the UAV Logger as a competitive economic alternative include small harvest volumes and high road build costs.
6

Minimum Energy Control Strategy for an Uninhabited Airship with a Moving Gondola

Mansur, Ali 07 January 2022 (has links)
An airship with a moving gondola is investigated with the goal of achieving a large pitch angle and of minimizing the total energy consumption required to goal position. The airship in this study is equipped with different actuation tools such as a moving gondola and a vectoring thrust, which can be used for various flight modes. The efficiency of the actuation methods employed is studied and compared in various flight scenarios, based on the airship’s ability to reach the desired position while consuming the least amount of energy. The nonlinear dynamic model is derived using Newton-Euler equations. Backstepping and incremental nonlinear dynamic inversion (INDI) controllers are designed to track a desired trajectory by controlling the position of the gondola and the thrust. The dynamic models are then implemented and simulated in the Matlab/Simulink to evaluate the effectiveness of the controllers in different environmental conditions. The simulation results show the effectiveness of the controllers used, and a larger pitch angle of -89o, can be reached thanks to the movement of the gondola to the front of the airship on the curved keel. The airship prototype was used for the experimental test to evaluate the pitch tracking performance of each of the controllers. The experimental results show that the prototype used can generate a -90o pitch angle, thereby improving manoeuvrability and allowing for rapid changes in altitude. The energy model is developed to evaluate and compare the energy required by the airship for ascent, cruise, and descent flights, using different actuation methods. The effectiveness of the composite control strategy is demonstrated by completing the flight mission with the least amount of energy consumed. An optimization method is then developed to find the optimum design configuration to reduce the cost function, based on energy consumption, of the different flight scenarios while always respecting the design constraints. The Heuristic technique is used to obtain the optimal flight trajectory based on the platform’s ability to complete the desired mission while minimising energy consumption. The results show that for pitch tracking, the vectored thrust has a rapid response, and the required thrust is high. Therefore, this configuration requires more energy than the moving gondola control configuration, in all cases studied. The composite configuration is found to be the most efficient method for completing the flight trajectory with the least amount of energy. The total energy consumption of the entire flight is reduced by about 17% by using the optimization algorithm to select the best actuation method for each flight mode.
7

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.
8

DECELERATION : Mobility Designed to be Slow / : A Mobility Designed to be Slow

Chen, Xintao January 2017 (has links)
What is next for the luxury experience when autonomous technology is replacing your private chau eur and there is no need for improving the performance of a vehicle? What if consumers simply get bored of rare and expensive materials as the only reference to luxury? There is a potential to change the mindset and rethink the value of mobility. As it is already happening, people start to treasure experiences rather than ownership. Vehicles play multiple important roles in our lives and some of our most precious stories can happen during a ride. Inspired by such insights, this project pushed the boundaries to envision a new kind of luxurious mobility experience designed to be slow. Research, ideation, storytelling, 3D modelling and visualisation were used to propose a shared airborne mobility service for the megacity. A system composed of dirigibles and docking stations, inspired and fictitiously operated by the Lexus brand.
9

Volvo Volem

Seifert, Moritz January 2018 (has links)
What if the future of transportation was more diverse, more exciting and more responsible? What if Volvo became a true mobility provider with a broader product palette? What if the airship would finally get its great renaissance and what would it look like if Volvo developed it? With these questions in mind, I started my thesis and eventually designed an airship for Volvo. The word Volvo is derived from Latin and means “I roll” which inspired me to pick the name “Volem” which is equally derived from Latin and means “I fly”. The focus of the degree work is transport in tourism and the final concept is a holistic service design for continental round-trips provided by Volvo. It is not just an airship but rather an entirely new way of traveling suited to the needs of future tourism. A journey of this future should be environmentally responsible, experientially enriching, educational and exciting. The key to this future is “Volvo Volem”. “Volvo Volem” has a comfortable main deck, an extraordinary lounge and an observation balcony which provides an unforgettable experience with its views. During the design process, I conducted some research in the field of tourism and in LTA (lighter-than-air) technologies. I used traditional design tools like sketching and 3D-modelling to refine my ideas. To get an impression of the interior I got the opportunity to test the geometry in virtual reality, which turned out to be a very helpful technology with increasingly indispensable characteristics in the design field.
10

Trajectory Optimization of a Small Airship

Blouin, Charles January 2015 (has links)
Pseudo-spectral optimal solvers are used to optimize numerically a performance index of a dynamical system with differential constraints. Although these solvers are commonly used for space vehicles and space launchers for trajectory optimization, few experimental papers exist on optimal control of small airships. The objective of this thesis is to evaluate the use of a pseudo-spectral optimal control solver for generating dynamically constrained, minimal time trajectories. A dynamical model of a small airship is presented, with its experimental virtual mass, drag and motor experimentally modeled. The problems are solved in PSOPT, a pseudo-spectral optimal control code. Experimental tests with a small scale model are performed to evaluate the generated paths. Although drift occurs, as a consequence of an open loop control, the vehicle is capable of following the path. This results of this thesis may find uses in verifying how close to optimal discreet path planners are, to plan complex trajectories on short distances, or to generate dynamic maneuverer such as take-off or landing. Ultimately, improving path planning of small airships will improve their safety, maneuverability and flight-time, which makes them fit for scientific monitoring, for search and rescue, or as mobile telecommunications platforms.

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