In recent years unmanned aircraft systems (UAS) have been successfully used in a wide variety of applications. Their value as surveillance platforms has been proven repeatedly in both military and civilian domains. As substitutes to human inhabited aircraft, they fulfill missions that are dull, dirty and dangerous. Representative examples of successful use of UAS are in areas including battlefield assessment, reconnaissance, port security, wildlife protection, wildfire detection, search and rescue missions, border security, resource exploration and oil spill detection. The reliance of almost every UAS application on the ability to sense, detect, see and avoid from a distance has motivated this thesis, attempting to further investigate this issue. In particular, among the various types of UAS, small scale unmanned rotorcraft or Vertically Take-off and Landing, (VTOL) vehicles have been chosen to serve as the sensor carrier platforms because of their operational flexibility. In this work we address the problem of object identification and tracking in a largely unknown dynamic environment under the additional constraint of real-time operation and limited computational power. In brief, the scope of this thesis can be stated as follows: Design a vision system for a small autonomous helicopter that will be able to: Identify arbitrary objects using a minimal description model and a-priori knowledge; Track objects of interest; Operate in real-time; Operate in a largely unknown, dynamically changing, outdoors environment under the following constraints: Limited processing power and payload; Low cost, off-the-shelf components. The main design directives remain that of real-time execution and low price, high availability components. It is in a sense an investigation for the minimum required hardware and algorithmic complexity to accomplish the desired tasks. After development, the system was evaluated as to its suitability in an array of applications. The ones that were chosen for that purpose were: Detection of semi-concealed objects; Detection of a group of ground robots; Traffic monitoring. Adequate performance was demonstrated in all of the above cases.

No description available.

Rotorcraft vehicles are highly sensitive to ice accretion. When ice forms on helicopter rotor blades, performance degradation ensues due to a loss of lift and rise in drag. The presence of ice increases torque, power required, and leads to rotor vibrations. Due to these undesirable changes in the vehicle's performance, the FAA requires intensive certification to determine the helicopter’s airworthiness in icing conditions. Since flight tests and icing tunnel tests are very expensive and cannot simulate all conditions required for certification, it is becoming necessary to use computational solvers to model ice growth and subsequent performance degradation. Currently, most solvers use the strip theory approach for 3D shapes. However, rotor blades can experience significant span-wise flow from separation or centrifugal forces. The goal of this work is to investigate the influence of span-wise flow on ice accretion. The classical strip theory approach is compared to a curved surface streamline based approach to assess the relative differences in ice formation.

Sedan helikopterns introduktion har den använts på en olika sätt i många olika militäroperationer. Dess unika egenskaper gör den till en bra vapenplattform. Trots detta har dess roller inom modern krigföring aldrig riktigt definierats. Studien syftar till att ta reda på vilka roller helikoptern kan ha inom manöverkrigföring. Detta görs genom att analysera manöverkrigföringens utmärkande drag mot helikopterns utmärkande drag. Därefter används fallstudier av Operation Desert Storm och Operation Iraqi Freedom för att se hur helikoptern har använts. Studien visar att helikopterns viktigaste roller inom manöverkrigföring är att stödja markförbanden med rörlighet och verkan. / Since the introduction of the helicopter it has been used in a variety of ways in many different military operations. Its unique properties make it a good weapon platform. Despite this, its roles in modern warfare have never really been defined. This study aims to find out what roles the helicopter may have in maneuver warfare. This is done by analyzing the characteristics of maneuver warfare and comparing it to the helicopter's characteristics. The study will use case studies of Operation Desert Storm and Operation Iraqi Freedom to see how the helicopter has been used. This study shows that the helicopter's main roles in maneuver warfare are to support ground troops with mobility and firepower

Thesis (M.S.M.E.)--Baylor University, 2008. / Includes bibliographical references (p. 101-102).

Thesis (M.S.)--Royal Roads University, 2005. / Includes bibliographical references (leaf 71-75). Project presentation at BC Mountain Goat Workshop (March 1, 2005) also available electronically via Internet.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: With a view to future ship deck landings, a moving platform landing algorithm for an unmanned autonomous helicopter was successfully designed and a number of systems were developed in order to implement the landing algorithm. Through a combination of an MCA-based ship motion prediction algorithm and the appropriate analysis of platform motion criteria, a system was developed which can identify valid landing opportunities in real ship motion data recorded at sea state 4 for up to 5 s into the future with a 75% success rate. The bandwidth of the heave motion estimator and controller of the helicopter were increased by the implementation of GPS latency compensation, and velocity and acceleration feed forward terms respectively. The resulting bandwidth of at least 0.2 Hz is sufficient to track the heave motion of a platform which is simulating the motion of a ship at sea state 4 or lower. After the various systems were integrated they were coordinated in a landing state machine. A stationary platform landing was demonstrated successfully during flight tests, verifying the functionality of the landing state machine and the integration of the system. Landings on a platform simulating the motion of a ship at sea state 4 were demonstrated successfully in hardware-in-the-loop simulations. / AFRIKAANSE OPSOMMING: Met die oog op toekomstige skip dek landings, is 'n bewegende platformlandingsalgoritme vir 'n onbemande outonome helikopter suksesvol ontwerp en 'n aantal stelsels ontwikkel om die landingsalgoritme te implementeer. Deur 'n kombinasie van 'n MCA-gebaseerde skipbewegingvoorspellingsalgoritme en die toepaslike ontleding van platformbewegingkriteria, is 'n stelsel ontwikkel wat geldige landingsgeleenthede in realeskipbewegingsdata kan identifiseer. Vir skipbewegingsdata wat by seetoestand 4 opgeneem is kan landingsgeleenthede 5 s in die toekoms met ‘n 75% sekerheid identifiseer word. Die bandwydte van die afgeebewegingafskatter en beheerder van die helikopter is deur die implementering van GPS vertragingkompensasie, en snelheid en versnelling vorentoe-voer terme onderskeidelik verhoog. Die gevolglike bandwydte van minstens 0.2 Hz is voldoende om die afgeebeweging van 'n platform te volg wat die beweging van 'n skip by seetoestand 4 of laer simuleer. Nadat die stelsels geïntegreer is is hulle gekoördineer in 'n landingtoestandsmasjien. 'n Stilstaande platform landing is suksesvol gedemonstreer tydens vlugtoetse, wat die funksionaliteit van die landingtoestandsmasjien en die integrasie van die stelsel bewys. Landings op 'n platform wat die beweging van 'n skip by seetoestand 4 simuleer is suksesvol in hardeware-in-die-lus simulasies gedemonstreer.

Este trabalho aborda o estudo de um sistema de referência inercial de posição e atitude e um sistema de controle para um helicóptero autônomo utilizando, como base para formulação e testes, o modelo linearizado da aeronave Yamaha R-MAX. Um sistema de referência inercial (INS) e um sistema de referência de atitude e orientação (AHRS) são utilizados para estimar a posição e atitude da aeronave, e estimadores robustos baseados no filtro de Kalman são empregados para minimizar os efeitos de incertezas paramétricas. É utilizada uma estratégia de controle em cascata com três malhas consistindo de uma malha interna para garantir a estabilidade do helicóptero (são utilizadas as técnicas LQR e H \'INFINITO\', separadamente), uma malha intermediária baseada em linearização por realimentação (FLC) para desacoplar os pares entrada/saída e uma malha externa baseada em um controlador proporcional-derivativo (PD) para permitir o rastreamento da trajetória. Resultados de simulação são apresentados para avaliar o desempenho de cada abordagem. / This work concerns the study of an inertial reference system and a control system for an autonomous helicopter using, as basis for the formulation and testing, the linearized mo del of the aircraft Yamaha R-MAX. An inertial navigation system (INS) and an attitude and orientation reference system (AHRS) are used to estimate the position and attitude of the aircraft and robust estimators based on Kalman filter are employed to minimize the effects of parametric uncertainties. A cascaded control architecture with three control methodologies is used, consisting of an inner-loop to ensure stability of the helicopter (the LQR and H \'INFINITE\' techniques are used, separately), a mid-loop based on linearization feedback (FLC) to decouple the dynamics ofthe lateral, longitudinal, vertical and heading axes and an outer-loop based on a proportional-derivative (PD) controller to enable trajectory tracking. Simulation results are presented to evaluate the performance of each approach.

När en helikopter befinner sig i brownout saknar besättningen referenser till omvärlden vilket kan försämra det spatiala medvetandet. Om besättningen inte har koll på helikopterns position i luftrummet kan det leda till skador på både materiel och besättning i samband med landning. Denna rapport undersökte, på ett övergripande plan, vilka möjligheter sensorer inom det elektromagnetiska spektret hade att bidra med information till det spatiala medvetandet. Rapporten fann att sensorerna behöver vara anpassningsbara till följd av stoftmolnets vida varierande karaktäristik. Sensorerna hade möjlighet att generera en bild av landningsplatsen före brownout inträffar. Radar lämpade sig bäst till att uppdatera bilden när brownout inträffat då de elektrooptiska sensorerna kraftigt begränsas av stoftmolnet. Däremot genererade de elektrooptiska sensorerna en bild av omgivningen som motsvarade ögats tolkning av samma omgivning, något som en radar har svårare att göra. / When a helicopter is in brownout the crew looses references to the world outside which could decrease the spatial awareness. If the crew does not know the accurate position of the helicopter it can lead to damage on both equipment and crew when landing. This report examined, on a general level, how sensors within the electromagnetic spectrum could contribute with information to the spatial awareness. The report found that the sensors need to be adaptable due to the widely varying characteristics of the dustcloud. The sensors were able to generate an image of the landingsite prior to brownout. Radar was best suited to updating the image when brownout had occurred, whereas the electro-optical sensors are highly attenuated by the dust cloud. However, the electro-optical sensors generated an image of the environment corresponding to the eye's interpretation of the same surrounding, something that a radar has greater difficulty with accomplishing.

Helikoptern som sjuktransport är ett väl beprövat system. Dess förmåga att landa och starta på nästintill vilka platser som helts gör den mycket lämplig för denna typ av arbete. Även om förmågan funnits i nästan 50 år är teoribildningen kring MEDEVAC bristande. I arbetet kommer helikopterns användande som MEDEVAC-­‐resurs under Vietnamkriget och Afghanistankriget att analyseras. I båda dessa fall analyseras även de doktriner som styr användandet av MEDEVAC. Brister i teoribildning kring MEDEVAC är centralt för detta arbete, då syftet är att belysa de brister i utveckling som det kan ha inneburit. De slutsatser som dras av dessa analyser är att den taktiska och doktrinära utvecklingen inte utvecklats i någon större utsträckning under denna period. De framsteg som har gjorts har framför allt varit teknisk utveckling samt att resursen värderas mer och används på ett försiktigare sätt. / The helicopter is regularly used for performing evacuation of sick and wounded. Its ability to take off and land almost anywhere makes it especially useful for these kinds of missions. Even though the ability to do this has been around for nearly 50 years, theories concerning MEDEVAC are lacking. This essay will examine the helicopters role as a MEDEVAC resource during the Vietnam war and the war in Afghanistan. The respective doctrines and Field Manuals that guide the usage of MEDEVAC helicopters will also be examined. The lack of theories in this field will be central in this essay, since the goal is to point out if any shortcomings in the evolution of the MEDEVAC helicopter could be a result of this.