• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • 2
  • 2
  • 1
  • Tagged with
  • 12
  • 5
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 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

Tethered Payload Control from an Autonomous Helicopter

May, James 26 October 2010 (has links)
A system is designed to deploy and support a tethered ground robot from an autonomous helicopter. A winch is designed and built. Electrical hardware for power distribution and control are designed. Several applied controls problems are investigated. A control architecture is established and low level controllers are designed to meet the demands of two higher level algorithms. A tether tension controller is designed to avoid the danger of excess slack in the tether interfering with the robot's mobility. A payload sway damping controller is investigated and simulated. Its is shown to be effective in damping dangerous payload oscillations by modulating the vertical manipulation of the winch during hoisting. Future design recommendations are given regarding improvements for a second design iteration. / Master of Science
2

Underslung Payload Tension Control from an Autonomous Unmanned Helicopter

McCabe, Brian John 07 June 2012 (has links)
A tension control algorithm for the deployment of a unmanned ground vehicle from an autonomous helicopter is designed and tested in this thesis. The physical hardware which the controller will run on is detailed. The plant model and underlying controllers are derived and modeled. The tension controller algorithm is selected, derived, and modeled. The parameters of the tension controller are chosen and simulations are run with the chosen parameters. The tension control algorithm is run on the physical hardware, successfully demonstrating tension control on a ground vehicle. Robustness simulations are run for a change in the radius of the spool and the length of the tether. Lastly, Future work is outlined on several paths to move forward with the tension controller. / Master of Science
3

Innovative Payloads for Small Unmanned Aerial System-Based Personal Remote Sensing and Applications

Jensen, Austin M. 01 May 2014 (has links)
Remote sensing enables the acquisition of large amounts of data, over a small period of time, in support of many ecological applications (i.e. precision agriculture, vegetation mapping, etc.) commonly from satellite or manned aircraft platforms. This dissertation focuses on using small unmanned aerial systems (UAS) as a remote sensing platform to collect aerial imagery from commercial-grade cameras and as a radio localization platform to track radio-tagged sh. The small, low-cost nature of small UAS enables remotely sensed data to be captured at a lower cost, higher spatial and temporal resolution, and in a more timely manner than conventional platforms. However, these same attributes limit the types of cameras and sensors that can be used on small UAS and introduce challenges in calibrating the imagery and converting it into actionable information for end users. A major contribution of this dissertation addresses this issue and includes a complete description on how to calibrate imagery from commercial-grade visual, near-infrared, and thermal cameras. This includes the presentation of novel surface temperature sampling methods, which can be used during the ight, to help calibrate thermal imagery. Landsat imagery is used to help evaluate these methods for accuracy; one of the methods performs very well and is logistically feasible for regular use. Another major contribution of this dissertation includes novel, simple methods to estimate the location of radio-tagged sh using multiple unmanned aircraft (UA). A simulation is created to test these methods, and Monte Carlo analysis is used to predict their performance in real-world scenarios. This analysis shows that the methods are able to locate the radio-tagged sh with good accuracy. When multiple UAs are used, the accuracy does not improve; however the sh is located much quicker than when one UA is used.
4

WIRELESS LAN FOR OPERATION OF HIGH RESOLUTION IMAGING PAYLOAD ON A HIGH ALTITUDE SOLAR-POWERED UNMANNED AERIAL VEHICLE

Herwitz, Stanley R., Leung, Joseph G., Aoyagi, Michio, Billings, Donald B., Wei, Mei Y., Dunagan, Stephen E., Higgins, Robert G., Sullivan, Donald V., Slye, Robert E. 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Two separate imaging payloads were successfully operated using a wireless line-of-sight telemetry system that was developed as part of a recently completed UAV (unmanned aerial vehicle) imaging campaign over the largest coffee plantation in the USA. The objective was to demonstrate the performance of “off-the-shelf” wireless technology in an effort to reduce the cost of line-of-sight telemetry for imaging payloads on UAVs. Pre-deployment tests using a conventional twin-engine piloted aircraft at a flight height of 10k ft demonstrated successful broadband connectivity between a rapidly moving (ca. 280 km hr^(-1)) airborne WLAN (wireless local area network) and a fixed ground station WLAN. This paper details the performance of the wireless telemetry system on a slow-flying (<50 km hr^(-1)) solar-powered UAV at a flight height of 6.4 km.
5

Developing Communication and Data Systems for Space Station Facility Class Payloads

Hazra, Tushar K., Sun, Charles, Mian, Arshad M., Picinich, Louis M. 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / The driving force in modern space mission control has been directed towards developing cost effective and reliable communication and data systems. The objective is to maintain and ensure error-free payload commanding and data acquisition as well as efficient processing of the payload data for concurrent, real time and future use. While Mainframe computing still comprises a majority of commercially available communication and data systems, a significant diversion can be noticed towards utilizing a distributed network of workstations and commercially available software and hardware. This motivation reflects advances in modem computer technology and the trend in space mission control today and in the future. The development of communication and data involves the implementation of distributed and parallel processing concepts in a network of highly powerful client server environments. This paper addresses major issues related to developing and integrating communication and data system and the significance for future developments.
6

Utvärdering av signaturdatabaser i systemet Snort / Evaluation of Signature Databases in the System Snort

Steinvall, Daniel January 2019 (has links)
Konstant uppkoppling till internet idag är en självklarhet för många världen över. Internet bidrar till en global förbindelse som aldrig tidigare varit möjligt, vilken kan tyckas vara underbart i många avseenden. Dessvärre kan denna digitala förbindelse missbrukas och användas för ondsinta ändamål vilket har lett till behov av säkerhetslösningar som bland annat nätverks-intrångsdetektionssystem. Ett av de mest omtalade verktygen som är ett exempel på ett sådant system är Snort som studeras i denna studie. Utöver analysering av Snort, evalueras även olika signaturdatabasers detektionsförmåga av angrepp. Totalt exekverades 1143 angrepp från 2008-2019 och dessa utvärderades av tre Snort-versioner daterade 2012, 2016 och 2018. Varje Snort-version analyserade angreppen med 18 signaturdatabaser daterade 2011-2019 från tre olika utgivare. Resultaten visar att det stor skillnad mellan de olika utgivarnas signaturdatabaser där den bästa detekterade runt 70% av angreppen medan den sämsta endast detekterade runt 1%. Även hur Snort konfigurerades hade stor inverkan på resultatet där Snort med för-processorn detekterade omkring 15% fler angrepp än utan den. / For many people all over the world being constantly connected to the Internet is taken for granted. The Internet connects people globally in a way that has never been possible before, which in many ways is a fantastic thing. Unfortunately, this global connection can be abused for malicious purposes which have led to the need for security solutions such as network intrusion detection systems. One prominent example of such a system is Snort which is the subject of evaluation in this thesis. This study investigates the ability of signature databases for Snort to detect cyberattacks. In total, we executed 1143 attacks released between 2008-2019 and recorded the network traffic. We then analyzed the network traffic using three versions of Snort released 2012, 2016, and 2018. For each version, we used 18 different signature databases dated 2011-2019 from three different publishers. Our results show that there are a significant difference between the different publishers’ signature databases, where the best signature database detected around 70% of the attacks and the worst only detected around 1%. The configuration of Snort also had a significant impact on the results, where Snort with the pre-processor detected about 15% more attacks than without it.
7

Desenvolvimento de uma plataforma para teste e controle de cargas-úteis baseada em arquitetura reconfigurável / Reconfigurable architecture based platform for test and control of satellite payloads

Guareschi, William do Nascimento January 2015 (has links)
O uso de pequenos satélites tem aumentado substancialmente nos últimos anos devido ao custo reduzido de desenvolvimento e lançamento, assim como pela flexibilidade oferecida pela utilização de componentes comerciais. Este trabalho propõe o projeto e a implementação de uma plataforma para teste, controle e qualificação de circuitos integrados (Integrated Circuits, CIs) comerciais e customizados para uso em aplicações espaciais. Esta plataforma flexível pode ser ajustada a uma gama de dispositivos e interfaces, e reduz os esforços de integração desses componentes e, portanto, acelera o desenvolvimento de todo o projeto. O sistema proposto é sintetizado em um tecnologia de Arranjo de Portas Programáveis em Campo (Field Programmable Gate Array) baseado em memória Flash, que, apesar de não ser classificado para uso aeroespacial, testes demonstram a viabilidade de seu uso. Este sistema adaptável permite o controle de novas cargas-úteis e softcores para o teste e validação antes da sua aplicação em voo. A comunicação com dispositivos é feita através de protocolos préimplementados. Os resultados de testes funcionais in loco sugerem a possibilidade de aplicação desta plataforma para uso em Cubesats. A primeira aplicação desta plataforma foi no teste do controle da placa de carga-útil do NanoSatC-BR1, o primeiro nanossatélite científico brasileiro, lançado em órbita em 2014. / The number of small satellites has substantially increased in the last years due to reduced development and launching costs, as well as due to the flexibility brought by the usage of commercial off the shelf components. This work purposes the design and implementation of a platform for test, control and qualification of commercial and customized integrated circuits for space applications. This flexible platform can be adjusted to control a wide range of devices and interfaces, and is intended to reduce the integration difficulties, resulting in the speed up of some of the project stages. The platform is synthesized in a Flash-based Field Programmable Gate Array technology. The target device is not qualified for aerospace projects. Nevertheless, previous radiation tests demonstrated its hardness for space missions. The system is adaptable and makes it possible to control, test and validate new payloads and softcores before flight. The communication between devices is done through pre-implemented protocols. Functional tests suggested the possibility to apply the platform in Cubesats projects. The first application of this platform was in the NanoSatC-BR1, the first Brazilian scientific nanosatellite, to test the controller of the payload board.
8

Galilean moon tour using simplified trajectory computational techniques

Williams, Ryan. January 2006 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 23, 2007) Includes bibliographical references.
9

Adaptive glide slope control for parafoil and payload aircraft

Ward, Michael 21 May 2012 (has links)
Airdrop systems provide a unique capability of delivering large payloads to undeveloped and inaccessible locations. Traditionally, these systems have been unguided, requiring large landing zones and drops from low altitude. The invention of the steerable, gliding, ram-air parafoil enabled the possibility of precision aerial payload delivery. In practice, the gliding ability of the ram-air parafoil can actually create major problems for airdrop systems by making them more susceptible to winds and allowing them to achieve far greater miss distances than were previously possible. Research and development work on guided airdrop systems has focused primarily on evolutionary improvements to the guidance algorithm, while the navigation and control algorithms have changed little since the initial autnomous systems were developed. Furthermore, the control mechanisms have not changed since the invention of the ram-air canopy in the 1960's. The primary contributions of this dissertation are: 1) the development of a reliable and robust method to identify a flight dynamic model for a parafoil and payload aircraft using minimal sensor data; 2) the first demonstration in flight test of the ability to achieve large changes in glide slope over ground using coupled incidence angle variation and trailing edge brake deflection; 3) the first development of a control law to implement glide slope control on an autonomous system; 4) the first flight tests of autonomous landing with a glide slope control mechanism demonstrating an improvement in landing accuracy by a factor of 2 or more in especially windy conditions, and 5) the first demonstrations in both simulation and flight test of the ability to perform in-flight system identification to adapt the internal control mappings to flight data and provide dramatic improvements in landing accuracy when there is a significant discrepancy between the assumed and actual flight characteristics.
10

Desenvolvimento de uma plataforma para teste e controle de cargas-úteis baseada em arquitetura reconfigurável / Reconfigurable architecture based platform for test and control of satellite payloads

Guareschi, William do Nascimento January 2015 (has links)
O uso de pequenos satélites tem aumentado substancialmente nos últimos anos devido ao custo reduzido de desenvolvimento e lançamento, assim como pela flexibilidade oferecida pela utilização de componentes comerciais. Este trabalho propõe o projeto e a implementação de uma plataforma para teste, controle e qualificação de circuitos integrados (Integrated Circuits, CIs) comerciais e customizados para uso em aplicações espaciais. Esta plataforma flexível pode ser ajustada a uma gama de dispositivos e interfaces, e reduz os esforços de integração desses componentes e, portanto, acelera o desenvolvimento de todo o projeto. O sistema proposto é sintetizado em um tecnologia de Arranjo de Portas Programáveis em Campo (Field Programmable Gate Array) baseado em memória Flash, que, apesar de não ser classificado para uso aeroespacial, testes demonstram a viabilidade de seu uso. Este sistema adaptável permite o controle de novas cargas-úteis e softcores para o teste e validação antes da sua aplicação em voo. A comunicação com dispositivos é feita através de protocolos préimplementados. Os resultados de testes funcionais in loco sugerem a possibilidade de aplicação desta plataforma para uso em Cubesats. A primeira aplicação desta plataforma foi no teste do controle da placa de carga-útil do NanoSatC-BR1, o primeiro nanossatélite científico brasileiro, lançado em órbita em 2014. / The number of small satellites has substantially increased in the last years due to reduced development and launching costs, as well as due to the flexibility brought by the usage of commercial off the shelf components. This work purposes the design and implementation of a platform for test, control and qualification of commercial and customized integrated circuits for space applications. This flexible platform can be adjusted to control a wide range of devices and interfaces, and is intended to reduce the integration difficulties, resulting in the speed up of some of the project stages. The platform is synthesized in a Flash-based Field Programmable Gate Array technology. The target device is not qualified for aerospace projects. Nevertheless, previous radiation tests demonstrated its hardness for space missions. The system is adaptable and makes it possible to control, test and validate new payloads and softcores before flight. The communication between devices is done through pre-implemented protocols. Functional tests suggested the possibility to apply the platform in Cubesats projects. The first application of this platform was in the NanoSatC-BR1, the first Brazilian scientific nanosatellite, to test the controller of the payload board.

Page generated in 0.06 seconds