This thesis presents the design of an autopilot capable of flying small unmanned aerial vehicles with wingspans less then 21 inches. The autopilot is extremely small and lightweight allowing it to fit in aircraft of this size. The autopilot features an advanced, highly autonomous flight control system with auto-launch and auto-landing algorithms. These features allow the autopilot to be operated by a wide spectrum of skilled and unskilled users. Innovative control techniques implemented in software, coupled with light weight, robust, and inexpensive hardware components were used in the design of the autopilot.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Wireless local area networks (WLANs) enable the extension of the Internet to aircrafts in flight. To establish this wireless network segment, commercial-of-the-shelve (COTS) 802.11b wireless Ethernet bridges were used. Wireless Ethernet bridges were chosen over optical wireless technology and Internet protocol (IP) satellite modems mainly because of their lower costs, ease and flexibility of implementation. Additionally, 802.11b wireless networks allow a wide range of mobile data devices such as laptop computers and personal digital assistance high-speed wireless access to critical information and applications resided on the aircrafts networks. Since 802.11b WLAN media is shared and traffic generated by other users will degrade the overall performance of the network. With the continual wide spread use of 802.11b WLAN, an aircraft in flight will experience network congestions and poor performance across all the frequency channels. The congestion and poor performance issues can be minimized by tracking the airborne wireless LAN using highly directional antenna and RF filtering. The method of tracking multiple 802.11 wirelesses LAN and the RF subsystem will be described. The applications of 802.11b wireless networks to man and unmanned aircrafts flight research will be discussed.

ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / Brigham Young University recently introduced a project for undergraduates in which a miniature unmanned aerial vehicle system is constructed. The system is capable of autonomous flight, takeoff, landing, and navigation through a planned path. In addition, through the use of video and telemetry collected by the vehicle, accurate geolocation of specified targets is performed. This paper outlines our approach and successes in facilitating this accomplishment at the undergraduate level.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Unmanned aerial vehicles with vertical take-off and landing capabilities have received extensive attention worldwide in the last decade. Their low detectability, high manoeuvrability in confined spaces, and their capability for out-of-sight operations make them practical solutions for an array of military and civilian missions. The main advantage of shrouded rotors in hover and low speed conditions is the decreased blade tip induced drag when the tip gap is small enough. A well-designed shroud augments the rotor thrust in hover and low axial flight conditions. It also provides noise reduction and safety. A contra-rotating rotor system eliminates the need for separate anti-torque devices, thus producing a smaller footprint and a more compact vehicle. In this study a more efficient coaxial rotor for the ducted coaxial rotor system as published by (Lee 2010) was developed. The first phase of the design process consisted of the selection and numerical analysis of the best suited parent airfoils for the rotors by using XFOIL and XFLR 5. The second phase dealt with the design of a counter-rotating rotor system for the existing cambered shroud as published by (Lee, 2010), using the DFDC-070ES2a two dimensional code, specifically written for ducted rotor optimization. The final phase of the study dealt with the Computational Fluid Dynamic (CFD) verification of the design in ANSYS-CFX 15.07. A comparison between the CFX predictions of the newly designed rotor system and the reference design indicates a 33% improvement in hover thrust at the design power input. / AFRIKAANSE OPSOMMING: Onbemande lugvaartuie met vertikale opstyg en landings vermoëns het uitgebreide aandag wêreldwyd in die laaste dekade geniet. Hul lae waarneembaarheid, hoë beweegbaarheid in beperkte ruimtes, en hul vermoë om buite-sig operasies uit te voer maak dat hulle praktiese oplossings vir 'n verskeidenheid van militêre en burgerlike missies is. Die grootste voordeel van gehulde rotors in hangvlug en lae spoed omstandighede is die afname in die lem punt sleepkrag wanneer die lem punt gaping klein genoeg is. 'n Goed ontwerpde omhulsel dra by tot die rotor stukrag in hangvlug en lae aksiale vlug omstandighede. Dit bied ook geraasreduksie en veiligheid. 'n Kontra-roterende rotorstelsel skakel die vereiste van afsonderlike anti-wringkrag toestelle uit, wat lei tot 'n kleiner voetspoor en 'n meer kompakte voertuig. In hierdie studie is 'n meer doeltreffende koaksiale rotor vir die gehulde koaksiale rotor stelsel soos gepubliseer deur (Lee 2010) ontwikkel. Die eerste fase van die ontwerp-proses het bestaan uit die seleksie en numeriese analise van die mees geskikte lemprofiele vir die rotors deur die gebruik van XFOIL en XFLR 5. Fase twee het die ontwerp van 'n teen-roterende rotor stelsel vir die bestaande omhulsel soos gebruik in (Lee, 2010) se publikasie behels. Die ontwerp is met behulp van DFDC-070ES2a, ‘n twee dimensionele kode wat spesifiek vir gehul-rotor optimering geskryf is, gedoen. Die verifikasie van die nuwe ontwerp is in die finale fase met behulp van die berekeings vloeidinamika sagteware, ANSYS-CFX 15.07 gedoen. ‘n Vergelyking tussen die CFX prestasie voorspelling vir die nuwe rotorstelsel en die gepubliseerde data van (Lee, 2010) toon ‘n 33% toename in hangvlug stukrag by die ontwerpsdrywing.

Performance of inflatable wings was investigated through laboratory, wind tunnel and flight-testing. Three airfoils were investigated, an inflatable-rigidazable wing, an inflatable polyurethane wing and a fabric wing restraint with a polyurethane bladder. The inflatable wings developed and used within this research had a unique outer airfoil profile. The airfoil surface consisted of a series of chord-wise \bumps.andamp;quot; The effect of the bumps or \surface perturbationsandamp;quot; on the performance of the wings was of concern and was investigated through smoke-wire flow visualization. Aerodynamic measurements and predictions were made to determine the performance of the wings at varying chord based Reynolds Numbers and angles of attack. The inflatable baffes were found to introduce turbulence into the free-stream boundary layer, which delayed separation and improved performance. Another area of concern was aeroelasticity. The wings contain no solid structural members and thus rely exclusively on inflation pressure for stiffness. Inflation pressure was varied below the design pressure in order to examine the effect on wingtip twist and bending. This lead to investigations into wing deformation due to aerodynamic loading and an investigation of wing flutter. Photogrammetry and laser displacement sensors were used to determine the wing deflections. The inflatable wings exhibited wash-in deformation behavior. Alternately, as the wings do not contain structural members, the relationship between stiffness and inflation pressure was exploited to actively manipulate wing through wing warping. Several warping techniques were developed and employed within this re-search. The goal was to actively influence the shape of the inflatable wings to affect the flight dynamics of the vehicle employing them. Researchers have developed inflatable beam theory and models to analyze torsion and bending of inflatable beams and other inflatable structures. This research was used to model the inflatable wings to predict the performance of the inflatable wings during flight. Design elements of inflatable wings incorporated on the UAVs used within this research are also discussed. Finally, damage resistance of the inflatable wings is shown from results of flight tests.

Recent miniaturization of computer hardware, MEMs sensors, and high energy density batteries have enabled highly capable mobile robots to become available at low cost. This has driven the rapid expansion of interest in multi-rotor unmanned aerial vehicles. Another area which has expanded simultaneously is small powerful computers, in the form of smartphones, which nearly always have a camera attached, many of which now contain a OpenCL compatible graphics processing units. By combining the results of those two developments a low-cost multi-rotor UAV can be produced with a low-power onboard computer capable of real-time computer vision. The system should also use general purpose computer vision software to facilitate a variety of experiments. To demonstrate this I have built a quadrotor UAV based on control hardware from the Pixhawk project, and paired it with an ARM based single board computer, similar those in high-end smartphones. The quadrotor weights 980 g and has a flight time of 10 minutes. The onboard computer capable of running a pose estimation algorithm above the 10 Hz requirement for stable visual control of a quadrotor. A feature tracking algorithm was developed for efficient pose estimation, which relaxed the requirement for outlier rejection during matching. Compared with a RANSAC- only algorithm the pose estimates were less variable with a Z-axis standard deviation 0.2 cm compared with 2.4 cm for RANSAC. Processing time per frame was also faster with tracking, with 95 % confidence that tracking would process the frame within 50 ms, while for RANSAC the 95 % confidence time was 73 ms. The onboard computer ran the algorithm with a total system load of less than 25 %. All computer vision software uses the OpenCV library for common computer vision algorithms, fulfilling the requirement for running general purpose software. The tracking algorithm was used to demonstrate the capability of the system by per- forming visual servoing of the quadrotor (after manual takeoff). Response to external perturbations was poor however, requiring manual intervention to avoid crashing. This was due to poor visual controller tuning, and to variations in image acquisition and attitude estimate timing due to using free running image acquisition. The system, and the tracking algorithm, serve as proof of concept that visual control of a quadrotor is possible using small low-power computers and general purpose computer vision software.

This project is part of research funded by NASA Langley in field of Unmanned Aerial Vehicles (UAVs) and is based on past work conducted at Virginia Commonwealth University. Dr. Mark A. Motter of NASA Langley intends to use the new autopilot system to test aircraft with many control surfaces. The goal of this project is to port an existing UAV autopilot system that has more computing power than the previous generation system to allow for more advanced flight control algorithms.The steps taken to complete this project include choosing a new hardware platform, porting C flight control software from a MicroBlaze platform to a PowerPC platform, and developing FPGA based hardware to interface with external sensors. The Suzaku-V based system was shown to have much better computing performance than the previous system, and several successful test flights have proved the viability of the new autopilot system.

The main objective of this thesis is to introduce a simulation platform, which has been developed utilizing Pogamut and USARSim, for cooperative aerial surveillance using multiple unmanned aerial vehicles (UAVs). The graphical user interface (GUI) of the simulator contains the automatically created bird's eye view of a 3D virtual environment. This is used to enter locations and parameters of objects (UAVs, charging stations and areas) and also to visualize the process of a simulation. The thesis proposes a system for the analysis of the quality of surveillance, whose results are presented in the GUI in the form of a time graph and a heat map. Part of the proposed platform is a UAV objective-based control system including charging stations scheduling. A total of seven algorithms for cooperative surveillance has been implemented, tested in three different scenarios and analyzed for coverage quality. Powered by TCPDF (www.tcpdf.org)

Unmanned Aerial Vehicle (UAV) is any flying vehicle which is not controlled by actual human pilots sitting in the cockpit but is installed with proper avionics that can either fly autonomously or by using the commands from its base. Some rotorcraft UAVs use a ducted propeller for two main reasons- safety and to increase the thrust produced by the propellers. While ducted rotors can increase the thrust produced, it also adds weight to the UAV. It was therefore hypothesized that by removing part of the duct materials (i.e. adding perforations in the duct) would benefit from both decreased duct weight and increased thrust. However, it is not clear how much trade-off would be between these two factors. Hence, the objective of this study is to explore the relationship between the change of thrust and addition of different numbers or sizes of perforations. Cases with and without duct, and duct with perforations were simulated using a commercial computational fluid dynamic (CFD) software Ansys/Fluent. The physics of the rotating propeller was modeled by a simplified disc with a pressure jump across an infinitesimal volume. Three different RPM speeds of the propellers were simulated by varying the strength of the pressure jump. The results show that the thrust decreases as the duct is added. As perforations are added, the result shows that with more perforations (i.e. more open area on the duct wall), the thrust increases accordingly until the thrust reaches a maximum value without the duct. The result is in contrast to a published experimental data stating that installation of duct can increase thrust. It is speculated that the current duct with a flat wall has caused such difference from the experimental data. Further study is recommended to continue more detailed computational simulation using a duct with cambered airfoil configuration to reduce the aerodynamic losses.

The popularity of using UAV in image-taking for the production of 3D models and orthophotos has increased over time. Karlskoga Municipality has recently acquired an UAV to produce their own 3D models and orthophotos. This project paper aims to study the geospatial accuracy of the orthophotos and DEM files produced using the images taken with their UAV. The flight takes only a few minutes but a considerable time is spent in the production processes. Difficulty is experienced in determining the right center point for most GCPs. Produced orthophotos in the software Photoscan have a resolution from 1.7 to 2.4 centimeters while DEM files have a resolution from 3.4 to 4.8 centimeters. Four orthophotos and four DEM files are produced where GCPs are used and not used and at two different flight heights, 76 and 105 meters. The spatial data of the ten GCPs are identified on the orthophotos and DEM files in ArcMap and compared with GNSS NRTK measurements and Lantmäteriet's data. A visual control in terms of completeness of data, alignment, residual tilt and scale is also done. Standard deviations in plane for orthophotos there GCPs are not used are greater than 2 meters, while there GCPs are used are around 0.7 meters. Standard deviations for DEM files are observed at 0.8 meters.