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Nowadays, the space industry is experiencing exponential growth, fueled by private companies and the conception of new and ambitious challenges. In recent years, the cost of reaching space has been drastically reduced, and to a certain extent, reusable rockets are to blame for that cost reduction. Unfortunately, and it has always been so, the space industry has always required a lot of resources and funding, and even with the drastic cost reduction with the incorporation of this new type of rockets, the development of technologies by students and researchers from universities around the world is still very difficult. To address this problem, this thesis will attempt, by reducing the cost to a maximum, to develop a system where it can study the dynamics of reusable rockets and be able to develop technologies around them. To do this, an unmanned aircraft system (UAS) will be designed from scratch with the main objective of imitating the behavior of this type of rocket while trying to reuse as many components already used by the university as possible, helping to reduce costs, and also helping to reduce the environmental impact of the project itself. Through the different chapters of this work, it can be seen, from the conception of the initial requirements and selection of the different components, to the 3D design and subsequent manufacturing of the system itself, which will be calibrated and tested in different test flights, taking advantage of the university's facilities. Ultimately, this work aims to serve as a useful tool for future students and researchers to deepen their knowledge of the attitude control of this type of rockets, and furthermore, to develop new technologies around the system that is intended to be designed and manufactured in this thesis.

The following project involves the design of a software capable of simulating take-off and landing operations to verify runway length requirements. To design the software, different mathematical models are studied and adapted according to the needs of the different phases into which both landing and take-off are divided. The simulations will be tested under different conditions of mass, weather, and wind.

Launched on 2 June 2003 and arriving at Mars on 25 December 2003 after a 7-month interplanetary cruise, Mars Express was the European Space Agency’s first mission to arrive at another planet. After more than 20 years in orbit, the spacecraft and science payload remain in good health and the mission has become the second oldest operational planetary orbiter after Mars Odyssey. This contribution summarizes the Mars Express mission operations, science planning and data archiving systems, processes, and teams that are necessary to run the mission, plan the scientific observations, and execute all necessary commands. It also describes the data download, the ground processing and distribution to the scientific community for the study and analysis of Mars sub-surface, surface, atmosphere, magnetosphere, and moons. This manuscript also describes the main challenges throughout the history of the mission, including several potentially mission-ending anomalies. We summarize the evolution of the ground segment to provide new capabilities not envisaged before launch, whilst simultaneously maintaining or even increasing the quality and quantity of scientific data generated. © The Author(s) 2024

The Generic Planning Tool (GPT) is a new software package being developed by the Flight Dynamics team at DLR. In an era where laser communications are becoming more and more relevant to data transmission for space missions, the GPT’s purpose is to compute highly accurate visibility windows and provide a wide variety of support information for both satellite-to-ground and inter-satellite links. What sets the GPT apart from previous products, is its shift from mission-specific to multi-mission and being able to accept various orbit and attitude data formats, thus enabling the support of multiple missions from DLR and external clients with flight dynamics information for mission planning applications. Its two main components are the core libraries written in Fortran, which serve as the powerhouse for the orbital mechanic’s computations, and the microservice architecture, enabled by JSON input/output files and Python scripts, which implement an automatic request-response service accessible over the network. This thesis will present why, how, and which GPT software functionalities were developed and tested during the internship at the German Space Operation Center., Det generiska planeringsverktyget, Generic planning tool (GPT), är ett nytt mjukvarupaket som utvecklas av den flygdynamiska avdelningen på DLR. I en tid när kommunikation med hjälp av laser blir alltmer relevant vid dataöverföringar för rymduppdrag, är syftet med GPT att beräkna mycket exakta öppningar för dataöverföringar, men också att bidra med en mängd olika sorters användbar information för både ”satellit-till-mark”- och ”satellit-tillsatellit”-länkar. Det som skiljer verktyget från tidigare produkter är dess omvandling från att vara uppdragsspecifik till att kunna hantera multipla uppdrag. I och med GPT:s förmåga att acceptera olika dataformat gällande omloppsbana och orientering, öppnar det upp för att kunna stödja multipla uppdrag från DLR och externa klienter med flygdynamisk information, för applikationer inom uppdragsplanering. GPT:s två huvudsakliga delar är, de centrala biblioteken skrivna i Fortran vilka verkar som ett kraftverk för de orbital-mekaniska beräkningarna, och mikroservice-arkitekturen skapad från JSON input/output-filer och Pythonskript, vilket implementerar en automatisk begär- och svarstjänst tillgänglig via nätverket. Detta examensarbete kommer presentera varför, hur och vilka av GPT:s mjukvarufunktioner som utvecklades och testades under praktikplatsen på German Space Operations Center (GSOC).

This thesis investigates the effectiveness of employing pretraining and a discrete "control signal" bottleneck layer in a neural network trained in aircraft navigation through deep reinforcement learning. The study defines two distinct tasks to assess the efficacy of this approach. The first task is utilized for pretraining specific parts of the network, while the second task evaluates the potential benefits of this technique. The experimental findings indicate that the network successfully learned three main macro actions during pretraining. flying straight ahead, turning left, and turning right, and achieved high rewards on the task. However, utilizing the pretrained network on the transfer task yielded poor performance, possibly due to the limited effective action space or deficiencies in the training process. The study discusses several potential solutions, such as incorporating multiple pretraining tasks and alterations of the training process as avenues for future research. Overall, this study highlights the challanges and opportunities associated with combining pretraining with a discrete bottleneck layer in the context of simulated aircraft navigation using reinforcement learning., Denna studie undersöker effektiviteten av att använda förträning och en diskret "styrsignal" som fungerar som flaskhals i ett neuralt nätverk tränat i flygnavigering med hjälp av djup förstärkande inlärning. Studien definierar två olika uppgifter för att bedöma effektiviteten hos denna metod. Den första uppgiften används för att förträna specifika delar at nätverket, medan den andra uppgiften utvärderar de potentiella fördelarna med denna teknik. De experimentella resultaten indikerar att nätverket framgångsrikt lärde sig tre huvudsakliga makrohandlingar under förträningen: att flyga rakt fram, att svänga vänster och att svänga höger, och uppnådde höga belöningar för uppgiften. Men att använda det förtränade nätverket för den uppföljande uppgiften gav dålig prestation, möjligen på grund av det begränsade effektiva handlingsutrymmet eller begränsningar i träningsprocessen. Studien diskuterar flera potentiella lösningar, såsom att inkorporera flera förträningsuppgifter och ändringar i träningsprocessen, som möjliga framtida forskningsvägar. Sammantaget belyser denna studie de utmaningar och möjligheter som är förknippade med att kombinera förträning med ett diskret flaskhalslager inom kontexten av simulerad flygnavigering och förstärkningsinlärning.

Small unmanned aircraft and electric vertical takeoff and landing (eVTOL) aircraft have recently emerged as vehicles able to perform new missions and stimulate future air transportation methods. This dissertation presents several system identification research advancements for these modern aircraft configurations enabling accurate mathematical model development for flight dynamics simulations based on wind-tunnel and flight-test data. The first part of the dissertation focuses on advances in flight-test system identification methods using small, fixed-wing, remotely-piloted, electric, propeller-driven aircraft. A generalized approach for flight dynamics model development for small fixed-wing aircraft from flight data is described and is followed by presentation of novel flight-test system identification applications, including: aero-propulsive model development for propeller aircraft and nonlinear dynamic model identification without mass properties. The second part of the dissertation builds on established fixed-wing and rotary-wing aircraft system identification methods to develop modeling strategies for transitioning, distributed propulsion, eVTOL aircraft. Novel wind-tunnel experiment designs and aero-propulsive modeling approaches are developed using a subscale, tandem tilt-wing, eVTOL aircraft, leveraging design of experiments and response surface methodology techniques. Additionally, a method applying orthogonal phase-optimized multisine input excitations to aircraft control effectors in wind-tunnel testing is developed to improve test efficiency and identified model utility. Finally, the culmination of this dissertation is synthesis of the techniques described throughout the document to form a flight-test system identification approach for eVTOL aircraft that is demonstrated using a high-fidelity flight dynamics simulation. The research findings highlighted throughout the dissertation constitute substantial progress in efficient empirical aircraft modeling s

Flexible aircraft designs with high-aspect-ratio wings and lightweight structures are increasingly adopted to achieve improved fuel efficiency. To design a controller for a flexible aircraft, a low-order model of its dynamics that captures the aeroelastic behavior is needed. One approach to establishing such a low-order model is to extend the six-degree-of-freedom rigid aircraft model with additional elastic states. However, most of the existing models along these lines are based on simplified aerodynamics models (e.g., experimentally corrected aerodynamic coefficients), which limits the applicability of such low-order models in early design stages. In this work, a semi-analytical model of flexible aircraft is established through the combination of the dynamics of elastic body and the numerical linearization of high-order structure and aerodynamics models. The proposed model is derived in the body-fixed axes formulation, represents full flight dynamics (both longitudinal and lateral), and preserves the physical meanings for the states and all the derived terms. Static residualization is also adopted to enhance the model's accuracy with a limited number of elastic states. Using the proposed approach, low-order semi-analytical models are exemplified for different complexity aircraft representations and verified against the corresponding nonlinear high-order models.

With a booming eVTOL market, many new companies will design their own vision of the future of urban transport. Therefore, a MATLAB flight dynamics model is needed to accurately design a Lift + Cruise Aircraft in the preliminary design phase. The MATLAB program is based on the EVE V3 aircraft by Embraer. The model successfully simulates an input flightpath and is highly customizable, providing preliminary design engineers with flexibility to modify and enhance the eVTOL aircraft. The program optimizes the input aircraft, accommodating up to 12 upward facing engines, 6 forward engines, 2 wings, and 2 stabilizers. The simulation-based approach reduces the need for physical prototyping and testing, offering a cost-effective tool for early-stage eVTOL aircraft development. Overall, this flight dynamics simulation proves instrumental in the preliminary design of Lift + Cruise eVTOL aircraft, providing engineers and designers with an indispensable asset for developing efficient, safe, and high-performance eVTOL technology., Aerospace Engineering

As the Flying-V goes through subsequent design iterations, each new model requires dedicated handling qualities research. A part of that work, namely obtaining the handling qualities predictions, is highly repetitive and can be automated. To address that issue, a Python library for automated handling qualities prediction evaluations of the Flying-V was developed. The library's functionalities cover model implementation, trim and linearization, model reductions, identification of the modal parameters, and finally, the evaluation of the requirements. The library takes a semi 'black-box' approach toward the model structure, relying on defining it through a set of functions instead of parameters. With that, it can accommodate various sources and formulations of the model. The library was successfully validated on two different aircraft models. Part of the validation was replicating some of the previous Flying-V handling qualities research data. It is expected that the use of the library will bring time savings to future handling qualities research of the Flying-V, as well as reduce the risk of mistakes in the process., Aerospace Engineering

Flight testing has been the historical standard for determining aircraft airworthiness - however, increases in the cost of flight testing and the accuracy of inexpensive CFD promote certification by analysis to reduce or replace flight testing. A framework is introduced to predict the performance in the special case of a modification to an existing, previously certified aircraft. This framework uses a combination of existing flight test or high fidelity data of the original aircraft as well as lower fidelity data of the original and modified configurations. Two methods are presented which estimate the model form uncertainty of the modified configuration, which is then used to conduct non-deterministic simulations. The framework is applied to an example aircraft system with simulated flight test data to demonstrate the ability to predict the performance and associated uncertainty of modified aircraft configurations. However, it is important that the models and methods used are applicable and accurate throughout the intended use domain. The factors and limitations of the framework are explored to determine the range of applicability of the framework. The effects of these factors on the performance and uncertainty results are demonstrated using the example aircraft system. The framework is then applied to NASA's X-57 Maxwell and each of its modifications. The estimated performance and associated uncertainties are then compared to the airworthiness criteria to evaluate the potential of the framework as a component to the certification by analysis process.

Aerospace Engineering

As the necessity of sustainable mobility rises, the demand to reduce the environmental impact of transporting mediums increases. The SUGAR Truss-Braced Wing (TBW) aircraft is a venture of Boeing, NASA and Virginia Tech for the N+3 generation of aircraft. These high-aspect-ratio aircraft are being designed with the aim to improve the structural and aerodynamic performance by implementing advanced technologies. Aerodynamics is a major factor influencing the performance of the aircraft, affecting the fuel consumption and emissions, especially due to drag. The multidisciplinary design optimization architecture for truss-braced-wing aircraft is dedicated to generate configurations with low fuel burn, maximum weight carrying capabilities and aircraft stability for long and medium range missions. The incorporation of flight dynamics at the conceptual design stage offers enhanced aerodynamic performance and wing flexibility for the aircraft. A robust flight dynamic system would need a detailed aerodynamic analysis of the aircraft with the focus on aeroelasticity. In this thesis, various aerodynamic coefficients and stability derivatives are investigated by applying Vortex-Lattice Method using OpenVSP, an open-source platform. The variation in aerodynamic parameters with changes in configurations and flow conditions are discussed as well. OpenVSP allows for study of these results with low computational expense. This will aid in efficient aerodynamic design and lay basis for flight dynamics analysis and its inclusion in the Multidisciplinary Design Analysis and Optimization (MDAO) framework.

Birds have always been a source of inspiration for humans. From the record distances crossed by the bar-tailed godwit during its migrations, to swifts staying aloft continuously for up to ten months, they are capable of achievements that artificial devices are still far from reproducing. We still have a lot to learn from the flight of birds, and the unveiling of the mechanisms behind their efficiency could open the way to new levels of performances for our man-made air vehicles. While many works have relied on observations and experimental measurements conducted on birds and have led us to a certain knowledge of their flight mechanisms, the present work builds upon the idea that reproducing bird flight in simulation can shed light on what makes them so efficient. Indeed, plain mimicry of the natural flight of birds does little toward the better understanding of its underlying principles whereas the numerical reproduction of the broad range of phenomena involved allows us to test various hypotheses. In this thesis, we report on the development of a model for bird flapping flight. This model includes a representation of the wing skeleton and the main flight feathers, controllers aimed at the stabilization of flight and a faithful modeling of the wake behind a bird. The model is applied to the study of the dynamics of a bird in controlled flight, the analysis of its wake and of the interactions between two birds flying in formation. In the results, we present predictions regarding the distribution of aerodynamic forces and the contributions to the flight power. We also analyze the structure of a bird wake, verifying hypotheses concerning the positioning of a bird flying behind another, and we simulate the formation flight of two birds, exploring the control strategies that stabilize the follower, and how its position affects the reduction in its flight power., Les oiseaux ont toujours été une source d’inspiration pour l’humanité. De la distance record parcourue par la barge rousse durant ses migrations annuelles, aux hirondelles capables de rester en vol ininterrompu pendant dix mois, ils sont capables de performances que nous sommes encore loin de pouvoir reproduire artificiellement. Nous avons encore beaucoup à apprendre du vol des oiseaux, et découvrir les mécanismes à l’origine de leur efficacité peut mener à de nouveaux niveaux de performances pour nos appareils volants. Malgré de nombreux travaux basés sur l’observation et des mesures expérimentales du vol des oiseaux, qui nous ont amené une certaine connaissance des mécanismes de leur vol, ce travail se base sur l’idée que la reproduction de ce vol en simulation peut nous éclairer sur ce qui le rend si efficace. En effet, une simple reproduction du vol des oiseaux tel qu’observé dans la nature ne suffit pas pour comprendre ses principes fondamentaux, tandis que la reproduction numérique de la large gamme de phénomènes impliqués dans le vol des oiseaux nous permet de tester des hypothèses. Dans cette thèse, nous présentons le développement d’un modèle du vol de l’oiseau à ailes battantes. Ce modèle comprend une représentation du squelette de l’aile et de ses principales plumes, des contrôleurs pour la stabilisation du vol, et un modèle fidèle du sillage derrière un oiseau. Le modèle est utilisé pour l’étude de la dynamique d’un oiseau en vol contrôlé, l’analyse de son sillage et les interaction entre deux oiseaux volant en formation. Dans les résultats nous présentons des prédictions concernant la distribution des forces aérodynamiques pendant le vol, et les différentes contributions à la consommation d’énergie. Nous analysons aussi la structure du sillage et vérifions des hypothèses concernant le positionnement d’un oiseau volant derrière un autre. Finalement, nous simulons le vol en formation de deux oiseaux, explorant ainsi les stratégies de contrôle disponibles, (FSA - Sciences de l'ingénieur) -- UCL, 2022

Flight testing has been the historical standard for determining aircraft airworthiness. However, increases in the cost of flight testing and the accuracy of inexpensive CFD encourage the adoption of certification by analysis to reduce or replace flight testing. A framework is introduced to predict the performance in the special case of a modification to an existing, previously certified aircraft. This framework uses a combination of existing flight tests or high fidelity data of the original aircraft as well as lower fidelity data from CFD or wind tunnel testing of the original and modified configurations to create 6-DOF flight dynamics models. Two methods are presented which generate an updated flight dynamics model and estimate the model form uncertainty for the modified aircraft configuration using knowledge of the original aircraft. This updated dynamics model and uncertainty estimate are then used to conduct non-deterministic simulations with wind turbulence included. The framework is applied to an example aircraft system to demonstrate the ability to predict the performance and associated model from the uncertainty of modified aircraft configurations.

Advancements in aircraft performance require increasingly complex design processes and tools. Simulating the unsteady non-linear aerodynamic interaction between a maneuvering aircraft and the surrounding flowfield poses serious challenges. High-Fidelity Computational Fluid Dynamics (CFD) methods, based on the numerical solution of the Navier-Stokes equations, can in general provide accurate solutions but at a computational cost that is often unfeasible for many applications that require real-time evaluation of the aerodynamic responses over a large range of conditions. Reduced Order Models (ROMs) are methods that can alleviate the computational burden of performing High-Fidelity simulations while providing accurate solutions over a wide extent of parametric variations. In the context of unsteady aerodynamics simulations, most traditional Reduced Order Models are limited to the prediction of integral loads and do not scale well for the treatment of high-dimensional systems. Recently, within the Science and Technology Organization work-group of NATO, a data-driven ROM based on the Proper Orthogonal Decomposition and Neural Networks (POD-LSTM) has been proposed for the prediction of the unsteady pressure fields on the UCAV MULDICON aircraft configuration, showing good potential in terms of computational efficiency and interpretability compared to the previously developed ROM based on end-to-end Convolutional Neural Networks. The POD-LSTM model is limited by the linear modal decomposition method that shows a slow convergence rate, in terms of latent space dimension, to the full-order solution. The high-projection error, localized in specific regions of the parameter space, translates into a consistent inaccuracy in the prediction of integral loads. In order to overcome these limitations, two main methodologies are proposed to replace the Global POD basis with modal bases localized in i) the computational space or ii) in the parameter space, yielding, Aerospace Engineering

[ES] Estudio aerodinámico del avión Panavia Tornado, incluyendo las dos posiciones extremas de la flecha alar. Estudio del comportamiento cuasiestacionario y dinámico, en una envolvente de vuelo limitada al régimen subsónico en su zona pre-crítica. Dinámica Lineal y algunos casos de la dinámica no Lineal., [EN] Aerodynamic study of the Panavia Tornado aircraft, including the wing sweep limit positions. Study of the near-steady and dynamic behavior, in a flight envelope limited to the subsonic regime in its pre-critical zone. Linear dynamics and some cases of non-linear dynamics.

The aim of the present paper is to present an understanding of the control characteristics for representative eVTOL (Electric Vertical Takeoff and Landing) quadcopters having the same properties of interest as the eVTOL configurations developed presently in Urban Air Mobility. In this context, the paper concentrates on eVTOL quadcopters with pure rpm control, pure propeller pitch control and both rpm and propeller pitch control. Dynamic effects of electric motors can potentially have significant effects on the flight characteristics of these vehicles. The paper will demonstrate for a pitch manoeuvre that while varying purely the rpm of the rotors results in a system that behaves as an acceleration-control system, varying purely the propeller pitch corresponds more to a velocity-control system. The rotor pitch control is more sensitive to the coupling rotor-motor and its transients dynamics. Varying both the rpm and the rotor pitch for controlling the pitch manoeuvre is the best option as this brings the system more towards velocity-control behaviour and dampens the transients due to the motor dynamics., Control & Simulation

A tiltrotor has the features of both a fixed-wing aircraft and a helicopter, thereby blending the vertical flight capabilities of helicopters with the speed, altitude, and range of fixed-wing aircraft. However, as an important aspect of piloted aircraft, the handling qualities of tiltrotor aircraft have not been studied extensively. This thesis presented a conceptual design and optimization framework to improve the handling qualities of the XV-15 tiltrotor aircraft. Handling qualities deficiencies of the XV-15 in conversion mode were investigated. The results in this thesis exhibited the influence of each design parameter on the handling qualities. The optimization results demonstrated that the handling qualities can be improved by adjusting the design parameters, but the increases in aircraft empty weight and power required are inevitable. The work done in this thesis contributes to the understanding of these design parameters' role in tiltrotor handling qualities, thus provides future tiltrotor designs with valuable knowledge., Aerospace Engineering

The research presented in this paper focuses on the development of a quasi-Linear Parameter Varying (qLPV) model for the XV-15 tiltrotor aircraft. The specific category of qLPV modeling technique, known as the model stitching technique, is employed to model the time-varying dynamics of XV-15 tiltrotor aircraft over the entire flight envelope. In this modeling approach, discrete linear state-space models are interpolated through lookup tables as function of scheduling parameters with the implementation of nonlinear equations of motion. The XV-15 qLPV model is configured with four scheduling parameters: altitude, nacelle incidence angle, wing flap angle and velocity. Additionally, a computational complexity analysis is presented. In particular, computational sensitivity of qLPV models configured with lookup tables to number of states and number of scheduling parameters is demonstrated. This is done to show the feasibility of real-time implementation of qLPV models with increasing fidelity (number of states) and expanding dynamic flight envelope (number of scheduling parameters)., Control & Simulation

Hydrobatic AUVsare very agile, and can perform challenging maneuvers that encompass the full 0 degrees-360 degrees flight envelope. Such AUVs can be beneficial in novel use cases in ocean production, environmental sensing, and security, by enabling new capabilities for docking, inspection, or under-ice operations. To further explore their capabilities in such scenarios, it is crucial to be able to model their flight dynamics over the full envelope, which includes strong nonlinear effects and turbulence at high angles of attack. With accurate and efficient simulation models, new hydrobatic maneuvers can be generated and control strategies can be developed. Therefore, this article contributes with a strategy to perform efficient and accurate simulations of hydrobatic maneuvers in real time. A multifidelity hydrodynamic database is synthesized by combining analytical, semiempirical, and numerical methods, thereby capturing fluid forces and moments over the full envelope. A component buildup workflow is used to assemble a nonlinear flight dynamics model using lookup tables generated from the database. This simulation model is used to perform real-time simulations of advanced hydrobatic maneuvers. Simulation results show agreement with literature and experiment, and the simulator shows utility as a development tool in designing new maneuvers and control strategies., QC 20211105

The study is conducted to determine practical modelling and simulation techniques to perform dynamic stability and performance analysis on a 3 Degrees of freedom aircraft model using a Modelica-based commercial tool called Modelon Impact. This study is based on a conceptual aircraft model where in-depth details about the aircraft configuration are unknown and the aim is to determine a suitable model that can capture the longitudinal dynamics and aerodynamic constraints of the aircraft during the conceptual design phase. Requirements include short execution time, easy model development, and minimal data requirements. Therefore, this thesis aims at developing plant and control architectures in Modelon Impact which can be utilized for the rapid development of aircraft concepts with adequate fidelity in a longitudinal mission-based tracking environment. In a conceptual aircraft design environment, to identify a suitable methodology that mitigates the limitations of a traditional feedback controller, two methodologies are considered for comparison: Sequential DAE resolution (SDR) and Dynamic inversion (DI) control which is discussed from an object-oriented aircraft model. The advantages and shortcomings of each of the models discussed above are compared by conducting several experiments in increasing order of longitudinal mission complexity, and the most appropriate model among the two for a conceptual stage of aircraft design development is ascertained. The two methodologies discussed are compared for their level of complexity, code structure, readability, and ease of usability.

A rocket is a vehicle that launches into space or describes a suborbital flight. It’s subjected to the forces of weight, thrust, and the aerodynamic forces, lift and drag. The relative magnitude and direction of the forces determines the flight trajectory of the rocket. The objectives of this paper are to model the rocket’s take-off trajectory and understand the tradeoff when using the main engine in conjunction with the lateral thrusters. Also, to obtain a linear model that represents the altitude obtained by the rocket in the ascending phase and to examine system behavior through stability and sensitivity analysis. Rocket’s trajectory is obtained in four situations depends on the engine or thrusters that are in operation. Linearization methods were used to replace the model by a simpler function due to the possibility of use tools for studying linear systems to analyze the behavior of a nonlinear function near a given point and because a linear model is required for certain types of analysis such as stability analysis. Finally, sensitivity analysis of the parameters of the model is used to study how the uncertainty in the output of a mathematical model can be apportioned to different sources of uncertainty in its inputs

This paper presents a rapid software prototyping environment (RSPE) for the design, simulation, and real-time implementation of a control system for an autonomous mini-helicopter. The software prototyping environment consists of diverse modules, including a mini-helicopter simulation model, a navigation filter, different controllers, a ground control station, and linearization and parameter identification tools. The environment is intended to reduce development time and costs, giving the designer more time to focus on mathematical and algorithmic methods. A hardware-in-the-loop (HIL) simulation example is presented to study the use and advantages of the prototyping environment in control design and simulation. Copyright © 2006 by EAFIT University.

[ES] El ISA 180 Seeker es un avión de doble brazo diseñado por el diseñador de aviones Ivan Shaw. Es un pequeño avión con capacidad para una persona. Con una longitud de 5,2 m y una envergadura de 5,8 m, este avión tiene una aerodinámica muy buena gracias a su condición de doble botavara y ala casi voladora. Estas características, además de un peso vacío de 260 kg, lo convierten en un avión ideal para estudiar la conversión a propulsión eléctrica. Por lo tanto, el proyecto consistirá en el diseño de un sistema de propulsión eléctrica adecuado para esta aeronave que sustituya al actual motor bóxer de 4 cilindros (Rotax 912 iS) y al resto del tren motopropulsor actual. Además, con el nuevo sistema de propulsión será necesario obtener un cierto nivel de rendimiento en términos de calidad de vuelo y especificaciones. Como punto de partida, Ivan Shaw compartió con nosotros el modelo X-Plane de su aeronave, y nos permitirá estudiar las actuales cualidades de vuelo y rendimiento para llevar a cabo el estudio deseado. En primer lugar, será necesario obtener datos técnicos de los datos actuales en términos de rendimiento aerodinámico, valores actuales de velocidad, pesos, ubicaciones, etc. Pero, la principal fuente de información serán los datos del modelo X Plane dado. Como hemos mencionado, el proyecto consistirá en estudiar una nueva configuración de propulsión eléctrica para esta aeronave en particular. Para ello, será necesario llevar a cabo una enorme investigación sobre las centrales eléctricas, utilizando como referencia algunos prototipos diseñados por las empresas (i.e. AIRBUS E-fan) o utilizando como guía para las baterías de la industria del automóvil, cuando se ha hecho una gran cantidad de mejoras en términos de almacenamiento de energía. (i.e. Tesla y Toyota). Será necesario determinar la batería óptima, el motor, los ESC de alta corriente, etc. En este proyecto también se evaluará la posibilidad de utilizar más de un motor, más de una batería y evaluar más de, [EN] The ISA 180 Seeker is a twin-boom aircraft designed by the aircraft designer Ivan Shaw. It is a small aircraft with capacity for one person. With a length of 5.2 m and a wingspan of 5.8 m, this aircraft has a very good aerodynamics thank to its condition of twin boom and almost flying wing. This Features, in addition to an Empty weigh of 260 kg, make it an ideal aircraft to study the conversion to electrical propulsion. Therefore, the project will consist on the design of a suitable electrical propulsion system for this aircraft replacing the current 4 cylinders boxer engine (Rotax 912 iS) and the rest of the current power train. Moreover, it will be necessary to obtain certain level of performance in terms of flying qualities and specifications with the new propulsion system. As a point of departure Ivan Shaw shared with us the X-Plane model of his aircraft, and it will allow us to study the current flying qualities and performance to carry out the desired study. First of all, it will be necessary to obtain technical data from the current data in terms of aerodynamic performance, current values of speed, weighs, locations, etc. But, the main source of information will be data from the X Plane model given. As we have mentioned the project will consist on study a new electrical propulsion configuration for this particular aircraft. For that, it will be necessary carry out a huge research on electrical power plants, using as a reference some prototypes designed by Companies (i.e. AIRBUS E-Fan) or using as a guide for batteries the automotive industry, when a large amount of improvements in term of energy storage has been done. (i.e. Tesla and Toyota). It will be necessary to determine the optimum battery, engine, high-current ESCs, etc. On this project it will be also assessed the possibility of using more than one engine, more than one battery and asses more than one type of power train configuration. Also giving to the aircraft a redundant propulsion system. On

The NASA Performance Adaptive Aeroelastic Wing (PAAW) project goals include significant reductions in fuel burn, emissions, and noise via efficient aeroelastic design and improvements in propulsion systems. As modern transport airplane designs become increasingly lightweight and incorporate high aspect-ratio wings, aeroservoelastic effects gain prominence in modeling and design considerations. As a result, the influence of the flight dynamics and controls on the optimal structural and aerodynamic design needs to be captured in the design process. There is an increasing interest in more integrated aircraft multidisciplinary design optimization (MDAO) processes that can bring flight control design into the early stage of an aircraft design cycle. So, in this thesis different flight dynamics modeling methodologies are presented that can be integrated within the MDAO framework. MDAO studies are conducted to maximize the controllability and observability of a UAV type aircraft using curvilinear SpaRibs and straight spars and ribs as the internal structural layout. The impulse residues and controllability Gramians are used as surrogates for the control objectives in the MDAO to maximize the controllability and observability of the aircraft. The optimal control designs are compared with those obtained using weight minimization as the design objective. It is found that using the aforementioned control objectives, the resulting aircraft design is more controllable and can be used to expand the flight envelope by up to 50% as compared to the weight minimized design.

This thesis proposes a general approach to solve the offline flight-maneuver identification problem using machine learning methods. The purpose of the study was to provide means for the aircraft professionals at the flight test and verification department of Saab Aeronautics to automate the procedure of analyzing flight test data. The suggested approach succeeded in generating binary classifiers and multiclass classifiers that identified six flight maneuvers of different complexity from real flight test data. The binary classifiers solved the problem of identifying one maneuver from flight test data at a time, while the multiclass classifiers solved the problem of identifying several maneuvers from flight test data simultaneously. To achieve these results, the difficulties that this time series classification problem entailed were simplified by using different strategies. One strategy was to develop a maneuver extraction algorithm that used handcrafted rules. Another strategy was to represent the time series data by statistical measures. There was also an issue of an imbalanced dataset, where one class far outweighed others in number of samples. This was solved by using a modified oversampling method on the dataset that was used for training. Logistic Regression, Support Vector Machines with both linear and nonlinear kernels, and Artifical Neural Networks were explored, where the hyperparameters for each machine learning algorithm were chosen during model estimation by 4-fold cross-validation and solving an optimization problem based on important performance metrics. A feature selection algorithm was also used during model estimation to evaluate how the performance changes depending on how many features were used. The machine learning models were then evaluated on test data consisting of 24 flight tests. The results given by the test data set showed that the simplifications done were reasonable, but the maneuver extraction algorithm could sometimes fail. Some maneuv

This paper aims at describing the effort performed by the joint research group of Politecnico di Torino and ZHAW (Zurich University of Applied Sciences) in achieving a novel implementation of a mathematical model for real-time flight simulation of tilt-rotors and tilt-wings aircraft. The focus is on the description of the current stage of the project, the achievements of the first version of the model, on-going improvements and future developments. The first part of the work describes the initial development of the overall simulation model: relying on several NASA reports on the Generic Tilt Rotor Simulator (GTRS), the mathematical model is revised and the rotor dynamic model is improved in order to enhance computational performance. In particular, the model uses the conventional mathematical formulation for non-dynamic inflow modelling based on Blade Element Momentum Theory. A novel but simple numerical method is used to ensure the convergence of the non-linear equation in every tested condition. The resulting simulation model and its development and implementation in the MATLAB/Simulink® environment is described. The second part of the work deals with the integration of the model in the ZHAW Research and Didactics Simulator (ReDSim), the replacement of the pilot controls by the introduction of a center stick and the corresponding adjustment of the force-feel system to suitable values for the tilt-rotor model. Subsequently, several pilot tests are carried out and preliminary feedbacks about the overall behaviour of the system are collected. Limits and weaknesses of the first release of the model are investigated and future necessary improvements are assessed, such as the development of a novel generic prop-rotor mathematical model. The third part introduces the novel multi-purpose rotor mathematical model which was developed to improve the overall tilt-rotor simulation model. The multi-purpose rotor model implements non-approximated flapping dynamics and inflow dyn

Differential thrust can be used for directional control on distributed electric propulsion aircraft. This thesis presents an assessment of flight dynamics and control of differential thrust aircraft under engine inoperative conditions with minimum control speed. A methodology consisting of an aerodynamic data acquisition module and a non-linear six-degrees-of-freedom flight dynamics model is proposed. The data acquisition module uses FlightStream solver to capture the aerodynamic performance data. The assessment consists of studying the aero-propulsive effects, control of the aircraft, rudder removal, and vertical tailplane size reduction. The directional control is achieved in the flight dynamics model by using a proportional–integral–derivative controller to generate a yaw command, which is distributed to the propulsors by thrust mapping. Additionally, drag mode is investigated, in which the outermost idling propulsors are used to generate maximum drag, allowing the non-idling inner propulsors to produce more thrust. A modified version of the NASA X-57 aircraft is selected as the case study aircraft. Results show that during the engine inoperative conditions at minimum control speed, the aircraft experiences significant loss in thrust and power augmented lift due to the failed propulsors and the directional control effort. Therefore, the stall and minimum control speed are increased, and the aircraft must accelerate to prevent a stall. Consequently, the aircraft experiences a temporary reduction in altitude during the recovery maneuver. Vertical tailplane reduction is seen possible, with differential thrust fully replacing the performance of the rudder. It was seen that the response time of the directional control has a significant impact on the maximum yawing angle and temporary altitude reduction. Finally, the use of drag mode reduced the maximum yaw angle and increased the climb gradient., Aerospace Engineering

Background: When seeking a human for a blood meal, mosquitoes use several cues to detect and find their hosts. From this knowledge, counter-flow odour-baited traps have been developed that use a combination of CO2, odour-blend, visual cues and circulating airflow to attract and capture mosquitoes. Initially developed for monitoring, these traps are now also being considered as promising vector control tools. These traps are attractive to host-seeking mosquitoes, but their capture efficiency is low. It has been hypothesized that the lack of short-range host cues such as heat and increased local humidity often prevents mosquitoes from getting close enough to get caught; this lack might even trigger avoidance manoeuvres near the capture region. Methods: We tested how close-range host cues affect the flight behaviour of Anopheles female malaria mosquitoes around odour-baited traps, and how this affects trap capture performance. For this, a novel counter-flow odour-baited trap was developed, the M-Tego. In addition to the usual CO2 and odour-blend, this trap can provide the short-range host cues heat and humidity. By systematically adding or removing these two cues, we tested how this affected the trap capture percentages and flight behaviour. We first compared capture percentages of the M-Tego with and without short-range host cues to the BG-Suna trap, in both laboratory and semi-field testing. Then, we used machine-vision techniques to track the three-dimensional flight movements of mosquitoes around the M-Tego. Results: With heat and humidity present, the M-Tego captured significantly more mosquitoes as capture percentages almost doubled. Comparing the flight behaviour around the M-Tego with variable close-range host cues showed that when these cues were present, flying mosquitoes were more attracted to the trap and spent more time there. In addition, we found that the M-Tego has a better capture mechanism than the BG-Suna, most likely because it does not elicit previ

As multi-rotor vehicles become integrated into the national airspace for applications such as package delivery and videography, it is important that the inner-loop control system be robust and able to meet ever-demanding performance constraints. To achieve high bandwidth control designs, it is necessary to have accurate and high bandwidth open-loop models. The material covered in this dissertation was aimed towards the flight-based identification and comprehensive understanding of the open-loop dynamics and aerodynamics of a multi-rotor vehicle despite the active feedback control system. The analytical first principles modeling and the discussion of system identification techniques informed the process for identifying the unstable multi-rotor dynamics. The inherently unstable nature of the vehicle, combined with the available measurements, necessitated a methodical approach towards identification from flight experiments. The non-negligible issue of unstable system identification was addressed by both the experiment design and the applied estimation technique. An individual propulsion system was tested on a hover stand to understand both the static and dynamic behavior of the combined propeller, motor, and electronic speed controller system. The results of the ground experiments influenced the design of the flight experiments, the postulation of the models, and the understanding of the estimated model parameters. The methodology for flight-based multi-rotor system identification involved the combined application of manual pilot inputs and automated multi-sine inputs added to the output of the controller. A series of five main flight tests were conducted for the identification of a high bandwidth open-loop linear rigid body model and two aerodynamic models of a multi-rotor vehicle. The comparison of the linear rigid body model with the two aerodynamics models emphasized the clear and substantial importance of the nonlinear rigid body coupling terms even in operations

Cyber-physical systems (CPSs) encompass a network of sensors and actuators that are monitored, controlled and integrated by a computing and communication core. As autonomous underwater vehicles (AUVs) become more intelligent and connected, new use cases in ocean production, security and environmental monitoring become feasible. Swarms of small, affordable and hydrobatic AUVs can be beneficial in substance cloud tracking and algae farming, and a CPS linking the AUVs with multi-fidelity simulations can improve performance while reducing risks and costs. In this paper, we present a CPS concept tightly linking the AUV network in ROS to virtual validation using Simulink and Gazebo. A robust hardware-software interface using the open-source UAVCAN-ROS bridge is described for enabling hardware-in-the-loop validation. Hardware features of the hydrobatic SAM AUV are described, with a focus on subsystem integration. Results presented include pre-tuning of controllers, validation of mission plans in simulation and real time subsystem performance in tank tests. These first results demonstrate the interconnection between different system elements and offer a proof of concept., QC 20201118

[EN] Project of helicopter flight dynamics, aerodynamic theory and flight mechanics.

Aircraft system identification has been widely used to this day in applications like control law design, building simulators or extending flight envelopes. It can also be utilized for determining flight-mechanical characteristics in the preliminary design phase of a flight vehicle. In this thesis, three common time-domain methods were implemented in MATLAB for determining the aerodynamic derivatives of a subscale aircraft. For parameter estimation, the equation-error method is quick, robust and can provide good parameter estimates on its own. The output-error method is computationally intensive but keeps account of the aircraft's evolution in time, being more suitable for fine-tuning predictive models. A new model structure is identified using multivariate orthogonal functions with a predicted squared error stopping criteria. This method is based on linear regression (equation-error). The code written is flexible and can also be used for other aircraft and with other aerodynamic models. Simulations are compared with experimental data from a previous flight test campaign for validation. In the future, this tool may help taking decisions in conceptual design after a prototype is tested.

Autopilot systems are used to complete missions without any human intervention or to assist the pilot durimng flight. In other words, they are used to make flight missions more reliable and efficient. The fiist step is a stabilizer mode when it comes to autopilot designing. Conventional autopilot systems have at least one inner an done outer loops. The stabilizer mode is the inner loop and, additional missions, such as speed, altitude, and heading hold are outer part of the system. From past to present, to control an autopilot system several types of methods are used. Although at th beginning classical control methods are used frequently, designing an autopilot system with modern control methods is much more preferable now. In this study with H_? loop-shaping contorl method which is one of the modern techniques, automatic flight for fixed-wing unmanned aerial vehicle will be provided. Primarily, the inner loop which is the stabilizer mode then outer loop which is the altitude hold is modeled in the MATLAB/Simulink environment. Flight dynamic coefficients and stability control derivatives are calculated for the generated aircraft model to be included in the control system. After the theorical steps above are taken, generated autopilot tested in both simulation and real flight. The main improvement of this thesis to literature is already existed H_? loop shaping control method is used for an autopilot which is designed including the full state flight dynamics and applied to real system., Otopilot sistemleri, insan müdahalesi gerektirmeden herhangi bir görevi tamamlamak için veya uçuşta pilota yardımcı olmak için kullanılan sistemlerdir. Bir başka deyişle, uçağın gerçekleştireceği görevi daha güvenilir ve etkili kılmak için kullanılırlar. Otopilot tasarımı sırasında ilk atılan adım otopilotun dengeleyici modudur. Geleneksel otopilot sistemlerinde en az bir iç ve bir de dış döngü bulunur. Dengeleyici mod otopilotun iç döngüsü olup, eklenecek diğer (hız, yükseklik, yön tutuşu gibi) görevler otopilotun dış döngüsünü oluşturur. Bir otopilot sistemini kontrol edebilmek için geçmişten günümüze pek çok yöntem uygulanmıştır. Başlangıçta klasik kontrol yöntemleri sıkça kullanılsa da günümüzde modern yöntemlerle tasarlanan otopilot sistemleri ağırlık kazanmıştır. Bu çalışmada, modern kontrol yöntemlerinden biri olan H_? çevrim şekillendirme kontrol metodu ile sabit kanatlı bir insansız hava aracının otomatik uçuşu sağlanacaktır. Önce otopilotun dengeleyici modu olan iç döngü, ardından yükseklik kontrolü yapan dış döngü, MATLAB/Simulink ortamında modellenmiştir. Kontrol sisteminde kullanılmak üzere, oluşturulan uçak modelinin uçuş dinamik katsayıları ve kararlılık kontrol türevleri belirlenmiştir. Yukarıdaki kuramsal adımlar atıldıktan sonra tasarlanan otopilot, sanal ortamda ve gerçek uçuş deneylerinde test edilmiştir. Önerilen tezin literatüre en büyük katkısı çevrim şekillendirme kontrol yönteminin uçuş dinamiklerinin tüm durumlarını kapsayacak şekilde tasarlanan bir otopilot sisteminde kullanılması ve gerçek sisteme uygulanmasıdır.

Modern aerodynamic analysis tools, such as free-vortex wake models and CFD-based techniques, include fewer theoretical limitations and approximations than classical simplified schemes, and represent the state-of-the-art in rotorcraft aerodynamic modeling, including for coaxial and other advanced configurations. However, they are impractical or impossible to apply to many flight dynamics problems because they are not formulated in ordinary differential equation (ODE) form, and they are often computationally intensive. Inflow models, for any configuration type, that couple the accuracy of high-fidelity aerodynamic models with the simplicity and ODE form of dynamic inflow-type theories would be an important contribution to the field of flight dynamics and control. This dissertation presents the methodology for the extraction of linearized ODE models from computed inflow data acquired from detailed aerodynamic free-vortex wake models, using frequency domain system identification. These methods are very general and applicable to any aerodynamic model, and are first demonstrated with a free wake model in hover and forward flight, for a single main rotor, and subsequently for the prediction of induced flow off the rotor as well, at locations such as the tail or fuselage. The methods are then applied to the extraction of first order linearized ODE inflow models for a coaxial rotor in hover. Subsequent analysis concluded that free-vortex wake models show that the behavior of the inflow of a coaxial configuration may be higher-order. Also, tip-path plane motion of a coaxial rotor causes wake distortion which has an impact on the inflow behavior. Therefore, the methodology is expanded to the identification of a second order inflow representation which is shown to better capture from all of the relevant dynamics from free-vortex wake models, including wake distortion. With ODE models of inflow defined for an advanced coaxial configuration, this dissertation then presents a comp

У раду је представљен интегрални приступ истраживању параметара пројектовања ракета са аспекта усаглашавања ограничења проистеклих из задатака механике при посебним условима гађања балистичких циљева који намећу различите конструктивне компромисе..., An integral approach has been presented on the research of missile design parameters from the aspect of harmonizing the limitations arising from the tasks of mechanics under the special conditions of hiting ballistic targets that impose various constructive compromises. Shooting target was analyzed for the most complex procedure of defense against ballistic targets. Basis on previous, it was establish criteria for require missile impact parameters and its ideal limit capabilities. The required normal acceleration, miss distance and control effort for each of the threshold missions are estimated. Based on the established criteria, a further aerodynamic design procedure is given, which is manifested through the selection of body geometric and aerodynamic performances, as well as appropriate control concepts for the requirements of the required maximum normal acceleration in the conditions of threshold flight missions. The synthesis of the autopilot of the vertical launch of the missile was performed, as well as the determination performances of the selected type of thrust vector control system and aerodynmaics for the purpose of hybrid control analysis. In particular, the propulsion performance assessment was carried out to integrate total flight and impact assessment of axial acceleration during the initial phase after vertical launch. The results of the influence parameters on the dynamic characteristics of the vertical launch of the missile in the active phase for hybrid control are presented. A mathematical model of possible use of a warhead for direct hit by an explosive-formed projectile was performed. Design approach and application of explosively-formed projectiles is presented as a potential useful warhead based on the adopted analytical and numerical methods.

Hydrobatics refers to agile maneuvering of under-water vehicles just like aerobatics represents agile maneuvering of aerial vehicles. Performance trade-offs between flight and hover style autonomous underwater vehicles (AUVs) means that either maneuverability or range is compromised. Hydrobatic capabilities in flight style AUVs can bridge this gap and lead to more efficient and agile vehicles; thereby encouraging disruptive designs. As this is a relatively new area of research with very limited published research work, the focus of this paper is to present a multidisciplinary literature review to provide a path forward for further research. Relevant impact areas in ocean production, environmental sensing and security are discussed. Technical challenges are described in underactuated control and flight dynamics modeling. Synergies and opportunities are explored with aerospace engineering, robotics and artificial intelligence. As a part of this study, a simulation and verification framework is suggested and ongoing work is presented., QC 20191024

Differential-geometric control theory exploits \textit{differential geometry} in the analysis of dynamical control systems. Differential geometry is a mathematical discipline that is concerned with studying calculus on curved (non-Euclidean) spaces. The main focus of this Dissertation is to formulate modern aeronautical engineering applications in a differential-geometric control framework. Nonlinear controllability analysis is one of the most important aspects of differential-geometric control theory. Its importance emanates from the fact that linear controllability conditions for linearized systems are not necessary. That is, there exists a class of nonlinear systems that are linearly uncontrollable but nonlinearly controllable. In particular, it allows for identification of the ability to generate motions along unactuated (nonintuitive) directions through specific interactions between the system dynamics and control inputs. In this Dissertation, differential-geometric control theory is utilized to analyze the nonlinear controllability of airplane flight dynamics. This study lead to several discoveries. First, it is found that an airplane in an upset situation where all control surfaces are blocked (inoperative) and linear controllability is lost, nonlinear controllability can be recovered using engine control only. More importantly, the study reveals unconventional mechanisms to generate motion along different directions in the state space. In particular, a novel roll mechanism that relies on nonlinear interactions between the elevator and aileron control surfaces is discovered. This novel roll mechanism is found to be superior in comparison to the conventional one (using ailerons only) near stall. Using differential-geometric control tools (e.g., non-holonomic motion planning and Fliess functional expansion), it is shown that the discovered roll mechanism can provide four times rolling motion near stall in comparison to the conventional roll control using ailero

[CA] El present Treball Final de Grau té com a objectiu l’estudi de l’aeronau SAAB J29F (TUNNAN) i l’estudi d’algunes maniobres que va poder realitzar al llarg de la seua vida útil., [ES] El presente Trabajo Final de Grado tiene como objetivo el estudio de la aeronave SAAB J29F (TUNNAN ) y el estudio de algunas maniobras que la aeronave pudo realizar a lo largo de su vida útil.

U radu je predstavljen integralni pristup istraživanju parametara projektovanja raketa sa aspekta usaglašavanja ograničenja proisteklih iz zadataka mehanike pri posebnim uslovima gađanja balističkih ciljeva koji nameću različite konstruktivne kompromise..., An integral approach has been presented on the research of missile design parameters from the aspect of harmonizing the limitations arising from the tasks of mechanics under the special conditions of hiting ballistic targets that impose various constructive compromises. Shooting target was analyzed for the most complex procedure of defense against ballistic targets. Basis on previous, it was establish criteria for require missile impact parameters and its ideal limit capabilities. The required normal acceleration, miss distance and control effort for each of the threshold missions are estimated. Based on the established criteria, a further aerodynamic design procedure is given, which is manifested through the selection of body geometric and aerodynamic performances, as well as appropriate control concepts for the requirements of the required maximum normal acceleration in the conditions of threshold flight missions. The synthesis of the autopilot of the vertical launch of the missile was performed, as well as the determination performances of the selected type of thrust vector control system and aerodynmaics for the purpose of hybrid control analysis. In particular, the propulsion performance assessment was carried out to integrate total flight and impact assessment of axial acceleration during the initial phase after vertical launch. The results of the influence parameters on the dynamic characteristics of the vertical launch of the missile in the active phase for hybrid control are presented. A mathematical model of possible use of a warhead for direct hit by an explosive-formed projectile was performed. Design approach and application of explosively-formed projectiles is presented as a potential useful warhead based on the adopted analytical and numerical methods.