A control system for autonomous landing of an unmanned aerial vehicle (UAV)with high precision has been developed. The UAV is a medium sized model he-licopter. Measurements from a GPS, a camera and a compass are fused with anextended Kalman filter for state estimation of the helicopter. Four PID-controllers,one for each control signal of the helicopter, are used for the helicopter control.During the final test flights fifteen landings were performed with an average land-ing accuracy of 35 cm.    A bias in the GPS measurements makes it impossible to land the helicopter withhigh precision using only the GPS. Therefore, a vision system using a camera anda pattern provided landing platform has been developed. The vision system givesaccurate measurement of the 6-DOF pose of the helicopter relative the platform.These measurements are used to guide the helicopter to the landing target. Inorder to use the vision system in real time, fast image processing algorithms havebeen developed. The vision system can easily match up the with the camera framerate of 30 Hz. / Ett kontrolsystem för att autonomt landa en modellhelikopter har utvecklats.Mätdata från en GPS, en kamera samt en kompass fusioneras med ett Extend-ed Kalman Filter för tillståndsestimering av helikoptern. Fyra PID-regulatorer,en för varje kontrolsignal på helikoptern, har används för regleringen. Under densista provflygningen gjordes tre landingar av vilken den minst lyckade slutade35 cm från målet.    På grund av en drift i GPS-mätningarna är det omöjligt att landa helikopternmed hög precision med bara en GPS. Därför har ett bildbehandlingssystem som an-vänder en kamera samt ett mönster på platformen utvecklats. Bidbehandlingssys-temet mäter positionen och orienteringen av helikoptern relativt platformen. Dessamätningar används kompensera för GPS-mätningarnas drift. Snabba bildbehan-dlingsalgoritmer har utvecklats för att kunna använda bildbehandlingssystemet irealtid. Systemet är mycket snabbare än 30 bilder per sekund vilket är kameranshastighet.

Due to its complex and multidisciplinary nature, the conceptual design phase of helicopters becomes critical in meeting customer satisfaction. Statistical (probabilistic) design methods can be employed to understand the design better and target a design with lower variability. In this thesis, a conceptual design and helicopter sizing methodology is developed and shown on a helicopter design for Turkey.

This thesis reports on a design study, conducted for an advanced composite helmet shell for helicopter pilots. The helmet shell is expected to provide a level of protection against low velocity impacts with its weight criteria. Therefore, ergonomy, light weight, and the ability to withstand low velocity impact became the main issues for this study. For this purpose, an experimental program has been developed including low velocity impact tests on specimens. The drop height, drop weight, specimen stacking sequences and size were constant parameters. Test specimens were produced using the plate size of 220x220 mm having different thicknesses. Specimen materials were aramid, carbon, and a hybrid form of these two. Thus, the parameters of the study were specimen thickness and the material types. The impact tests are carried out on a specially designed test rig. The design decisions are made in accordance with the results of the experiments. In compliance with the lightweight and manufacturing criteria, the hybrid specimen was selected helmet shell. For the purpose of ergonomy a geometric design was also conducted from headfrom sizes of Turkish Army by using 3D design software. After specifying the composite material, manufactured helmet shell was tested in another test rig according to the ANSI Z90.1.1992. For the requirement of the acceleration level 300g, the helmet shell design was found to be successful at seven different and critical impact points.

The main characteristic attribute of the rotorcraft is the use of rotary wings to produce the thrust force necessary for motion. Therefore, rotorcraft have an advantage relative to fixed wing aircraft because they do not require any relative velocity to produce aerodynamic forces. Rotorcraft have been used in a wide range of missions of civilian and military applications. Particular interest has been concentrated in applications related to search and rescue in environments that impose restrictions to human presence and interference. The main representative of the rotorcraft family is the helicopter. Small scale helicopters retain all the flight characteristics and physical principles of their full scale counterpart. In addition, they are naturally more agile and dexterous compared to full scale helicopters. Their flight capabilities, reduced size and cost have monopolized the attention of the Unmanned Aerial Vehicles research community for the development of low cost and efficient autonomous flight platforms. Helicopters are highly nonlinear systems with significant dynamic coupling. In general, they are considered to be much more unstable than fixed wing aircraft and constant control must be sustained at all times. The goal of this dissertation is to investigate the challenging design problem of autonomous flight controllers for small scale helicopters. A typical flight control system is composed of a mathematical algorithm that produces the appropriate command signals required to perform autonomous flight. Modern control techniques are model based, since the controller architecture depends on the dynamic description of the system to be controlled. This principle applies to the helicopter as well, therefore, the flight control problem is tightly connected with the helicopter modeling. The helicopter dynamics can be represented by both linear and nonlinear models of ordinary differential equations. Theoretically, the validity of the linear models is restricted in a certain region around a specific operating point. Contrary, nonlinear models provide a global description of the helicopter dynamics. This work proposes several detailed control designs based on both dynamic representations of small scale helicopters. The controller objective is for the helicopter to autonomously track predefined position (or velocity) and heading reference trajectories. The controllers performance is evaluated using X-Plane, a realistic and commercially available flight simulator.

This thesis describes the analysis, fabrication and testing of a rotor with extremely flexible blades, focusing on application to a micro-helicopter. The flexibility of the rotor blades is such that they can be rolled into a compact volume and stowed inside the rotor hub. Stiffening and stabilization of the rotor is enabled by centrifugal forces acting on a tip mass. Centrifugal effects such as bifilar and propeller moments are investigated and the torsional equation of motion for a blade with low torsional stiffness is derived. Criteria for the design of the tip mass are also derived and it is chosen that the center of gravity of each blade section must be located ahead of the aerodynamic center. This thesis presents the design of 18-inch diameter two-bladed rotors having untwisted circular arc airfoil profile with constant chord. A systematic experimental investigation of the effect of various blade parameters on the stability of the rotor is conducted in hover and forward flight. These parameters include blade flexibility in bending and torsion, blade planform and mass distribution. Accordingly, several sets of blades varying these parameters are constructed and tested. It is observed that rotational speed and collective pitch angles have a significant effect on rotor stability. In addition, forward flight velocity is found to increase the blade stability. Next, the performance of flexible rotors is measured. In particular, they are compared to the performance of a rotor with rigid blades having an identical planform and airfoil section. It is found that the flexible blades are highly twisted during operation, resulting in a decreased efficiency compared to the rigid rotor blades. This induced twist is attributed to an unfavorable combination of tip body design and the propeller moment acting on it. Consequently, the blade design is modified and three different approaches to passively tailor the spanwise twist distribution for improved efficiency are investigated. In a first approach, extension-torsion composite material coupling is analyzed and it is shown that the centrifugal force acting on the tip mass is not large enough to balance the nose-down twist due to the propeller moment. The second concept makes use of the propeller moment acting on the tip mass located at an index angle to produce an untwisted blade in hover. It is constructed and tested. The result is an untwisted 18-inch diameter rotor whose maximum Figure of Merit is equal to 0.51 at a blade loading of 0.14. Moreover, this rotor is found to be stable for any collective pitch angle greater than 11 degrees. Finally, in a third approach, addition of a trailing-edge flap at the tip of the flexible rotor blade is investigated. This design is found to have a lower maximum Figure of Merit than that of an identical flexible rotor without a flap. However, addition of this control surface resulted in a stable rotor for any value of collective pitch angle. Future plans for increasing the efficiency of the flexible rotor blades and for developing an analytical model are described. / text

Les limitations d’atterrissage des hélicoptères ne sont pas valables dans l'environnement à bord d’un navire. Il n'existe aucune méthodologie approuvée de l'analyse ou de la simulation pour évaluer la compatibilité des hélicoptères-navires et préparer les essais de qualification hélicoptères-navires. Dans ce contexte, le présent travail présente le développement et l'analyse d'une méthodologie hors ligne pour déterminer les limites opérationnelles hélicoptères-navires, SHOLs, en fonction des prédictions d’un modèle de pilote humain. Pour cela, des essais pilotés par des humains sont effectués au simulateur de l’ONERA, Salon de Provence. Sur la base des résultats de ces tests, une méthodologie innovante est validée pour déterminer la limitation de la charge de travail de pilotage, à partir des mesures des déplacements des contrôles d'hélicoptère. En outre, sont validés des modifications innovantes sur un modèle de pilote humain pour pouvoir suivre les trajectoires souhaitées et fournir le même niveau d'activité aux contrôles qu'un véritable pilote. Un ensemble de critères objectifs, correspondant aux marges de sécurité, s'ajoute aux critères subjectifs, correspondant aux limitations de la charge de travail du pilote. Une routine de simulation hors ligne, appelée SholSim, est programmée pour réaliser des simulations avec le modèle pilote et vérifier l'acceptabilité des conditions de vol, selon les critères subjectifs et objectifs. Par conséquent, le présent travail présente la première estimation, dans la littérature, des SHOLs entièrement obtenus à partir d'outils hors ligne, basés uniquement sur les prédictions de modèle pilote. / Helicopter land-based limitations are not valid in the shipboard environment. There is no analytical or simulated approved methodology for evaluating shipboard helicopter compatibility issues and preparing for at-sea flight tests. In this context, the present work presents the development and analysis of an offline methodology to determine the Ship-Helicopter Operating Limitations, SHOLs, based on pilot model predictions. For this, pilot-in-the-loop simulation trials are performed at the engineering fixed-base simulation facility of ONERA, Salon de Provence. Based on these test results, an innovative methodology is proposed and validated to determine the safe pilot workload limitation, from the measurements of the helicopter control displacements. In addition, it is proposed and validated innovative modifications on a classical pilot model enabling to follow complex predefined desired trajectories and provide the same level of control activity of a real pilot. A set of objective criteria, corresponding to the safety margins, is established in addition to the subjective criteria, corresponding to the safe pilot workload limitations. An offline simulation routine, so-called SholSim, is coded to run all models and verify the acceptability of the flight conditions, according to the subjective and objective criteria. Therefore, the present work presents the first estimation, in the literature, of the SHOLs fully obtained from offline tools, based only on pilot model predictions. The proposed methodology is promising, confirmed by predicting coherent limits when compared to the ones defined by the pilot-in-the-loop simulation trials.

Made available in DSpace on 2016-08-29T11:12:16Z (GMT). No. of bitstreams: 1 tese_6649_Dissertação - André Manhães.pdf: 1047859 bytes, checksum: 5602733dce0d5f103f7c07c76367c8c4 (MD5) Previous issue date: 2013-09-16 / O petróleo é a principal fonte energética do mundo contemporâneo, insumo básico de diversos setores econômicos. Com a descoberta do Pré-sal, o Brasil tem a oportunidade de tornar-se um dos maiores produtores de petróleo. Entretanto, para que isso seja alcançado, vários desafios deverão ser superados e, dentre eles, encontra-se o problema de transporte de empregados para operarem as plataformas offshore, distantes até 300km de distância da costa brasileira. Os problemas referentes ao deslocamento de empregados por meio de helicópteros são usualmente tratados como o Capacitated Helicopter Routing Problem (CHRP). Com base nas restrições de origem e de destino de cada cliente, no número de veículos e na capacidade e restrições de voo dos helicópteros, neste tipo de problema deseja-se minimizar os custos de aluguel de helicópteros mais o custo total de quilômetros voados. A presente dissertação propõe um modelo de Programação Linear Inteira Mista (PLIM) para o problema de roteirização de helicópteros com base no Dial-a-Ride Problem (DARP). Além do modelo apresentado, foram apresentados duas abordagens para a execução do modelo de forma exata: i) abordagem sem agrupamento, na qual as requisições que possuem origens iguais e destinos iguais são modeladas como requisições distintas e ii) abordagem com agrupamento, na qual requisições que possuem origens iguais e destinos iguais são aglutinados numa nova e única requisição. O modelo matemático foi executado no software CPLEX e os resultados mostraram que instâncias com até 25 requisições podem ser resolvidas pela abordagem com agrupamento / Oil is the main energy source of contemporary world; it is basic inputs of various economic sectors. With the discovery of Brazil pre-salt, there is an opportunity to become one of the largest oil producers. However, to achieve her own goals, Brazil must overcome several challenges, including the problem of transporting employees to operate offshore platforms 300km distant away from the Brazilian coast. Problems related to displacement of employees by helicopters are usually treated as Capacitated Helicopter Routing Problem (CHRP). Based on source and destination restrictions of each client, the number of vehicles, capacity and helicopter flight constraints, this type of problem proposes to minimize the cost of renting helicopters and the total cost of flown kilometers. This dissertation proposes a model of Mixed Integer Linear Programming (MILP) for the helicopters routing problem based on a Dial-a-Ride Problem (DARP). Besides the presented model, we presented two approaches to implementing the model in an exact way: i) non-clustered approach, in which requests that have the same origin and destination are equal modeled as separate requests; and ii) clustered approach, in which requests that have the same origins and destinations are clumped together in a new single request. The mathematical model was implemented in software CPLEX and results showed that instances with up to 25 requests can be resolved in the clustered approach

The present work draws together all current literature on particle separating devices and presents a review of the current research on rotor downwash-induced dust clouds. There are three types of particle separating device: vortex tube separators; inlet barrier filters; and inlet particle separators. Of the three, the latter has the longest development history; the former two are relatively new retrofit technologies. Consequently, the latter is well-represented in the literature, especially by computational fluid dynamics simulations, whereas the other two technologies, with specific application to rotorcraft, are found to be lacking in theoretical or numerical analyses. Due to their growing attendance on many rotorcraft currently in operation, they are selected for deeper investigation in the present work.The inlet barrier filter comprises a pleated filter element through which engine bound air flows, permitting the capture of particles. The filter is pleated to increase its surface area, which reduces the pressure loss and increases the mass retention capability. As particles are captured, the filter's particle removal rate increases at the expense of pressure loss. The act of pleating introduces a secondary source of pressure loss, which gives rise to an optimum pleat shape for minimum pressure drop. Another optimum shape exists for maximum mass retention. The two optimum points however are not aligned. In the design of inlet barrier filters both factors are important. The present work proposes a new method for designing and analysing barrier filters. It is found that increasing the filter area by 20% increases cycle life by 46%. The inherent inertial separation ability of side-facing intakes decreases as particles become finer; for the same fine sand, forward-facing intakes ingest 30% less particulate than side-facing intakes. Knowledge of ingestion rates affords the prediction of filter endurance. A filter for one helicopter is predicted to last 8.5 minutes in a cloud of 0.5 grams of dust per cubic metre, before the pressure loss reaches 3000 Pascals. This equates to 22 dust landings.An analytical model is adapted to determine the performance of vortex tube separators for rotorcraft engine protection. Vortex tubes spin particles to the periphery by a helical vane, whose pitch is found to be the main agent of efficacy. In order to remove particles a scavenge flow must be enacted, which draws a percentage of the inlet flow. This is also common to the inlet particle separator. Results generated from vortex tube theory, and data taken from literature on inlet particle separators permit a comparison of the three devices. The vortex tube separators are found to achieve the lowest pressure drop, while the barrier filters exhibit the highest particle removal rate. The inlet particle separator creates the lowest drag. The barrier filter and vortex tube separators are much superior to the inlet particle separator in improving the engine lifetime, based on erosion by uncaptured particles. The erosion rate predicted when vortex tube separators are used is two times that of a barrier filter, however the latter experiences a temporal (but recoverable post-cleaning) loss of approximately 1% power.

This thesis deals with design, development and testing of device for collecting fly data in ultralight airplane or helicopter. The basic collected value is a count of fly hours of each pilot. Additional fly data are latitude, longitude and altitude. Purpose of this device is a fair pricing for use of the airplane. Another utilization is in analysis of flight path or in pilot training. This device is succesfully made from miniature computer Raspberry Pi and uses GPS data. A reader will be informed about aviation regulations, embedded systems, global positioning system and wireless internet connection.

The concept of human-powered vertical flight was studied in great depth. Through the manipulation of preexisting theory and analytical methods, a collection of design tools was created to expediently conceptualize and then analyze virtually any rotor. The tools were then arranged as part of a complete helicopter rotor design process. The lessons learned as a result of studying this process—and the tools of which it consists—are presented in the following discussion. It is the belief of the author that by utilizing these tools, as well as the suggestions that accompany them, future engineers may someday build a human-powered helicopter capable of winning the Sikorsky Prize.