Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: A strategy for the design of an effective, practically feasible, robust, computationally efficient autopilot for three dimensional manoeuvre flight control of Unmanned Aerial Vehicles is presented. The core feature of the strategy is the design of attitude independent inner loop acceleration controllers. With these controllers implemented, the aircraft is reduced to a point mass with a steerable acceleration vector when viewed from an outer loop guidance perspective. Trajectory generation is also simplified with reference trajectories only required to be kinematically feasible. Robustness is achieved through uncertainty encapsulation and disturbance rejection at an acceleration level. The detailed design and associated analysis of the inner loop acceleration controllers is carried out for the case where the airflow incidence angles are small. For this case it is shown that under mild practically feasible conditions the inner loop dynamics decouple and become linear, thereby allowing the derivation of closed form pole placement solutions. Dimensional and normalised non-dimensional time variants of the inner loop controllers are designed and their respective advantages highlighted. Pole placement constraints that arise due to the typically weak non-minimum phase nature of aircraft dynamics are developed. A generic, aircraft independent guidance control algorithm, well suited for use with the inner loop acceleration controllers, is also presented. The guidance algorithm regulates the aircraft about a kinematically feasible reference trajectory. A number of fundamental basis trajectories are presented which are easily linkable to form complex three dimensional manoeuvres. Results from simulations with a number of different aircraft and reference trajectories illustrate the versatility and functionality of the autopilot. Key words: Aircraft control, Autonomous vehicles, UAV flight control, Acceleration control, Aircraft guidance, Trajectory tracking, Manoeuvre flight control. / AFRIKAANSE OPSOMMING: ’n Strategie vir die ontwerp van ’n effektiewe, prakties haalbaar, robuuste, rekenkundig effektiewe outoloods vir drie dimensionele maneuver vlugbeheer van onbemande vliegtuie word voorgestel. Die kerneienskap van die strategie is die ontwerp van oriëntasie-onafhanklike binnelus-versnellingbeheerders. Hierdie beheerders stel die navigasie buitelus in staat om die voertuig as ’n puntmassa met ’n stuurbare versnellingsvektor te beskou. Trajekgenerasie is ook vereenvoudig deurdat verwysingstrajekte slegs kinematies haalbaar hoef te wees. Robuustheid word verkry deur onsekerhede en versteuringsverwerping op ’n versnellingsvlak te hanteer. Die gedetaileerde ontwerp en saamhangende analise van die binnelus versnellingsbeheerders word uitgevoer vir die geval waar die invalshoeke klein is. Dit word aangetoon dat, onder praktiese omstandighede, die binnelus dinamika ontkoppel kan word en lineêr word, wat die afleiding van geslotevorm poolplasingoplossings toelaat. Dimensionele en genormaliseerde, nie-dimensionele tydvariante van die binnelusbeheerders word ontwerp en hul onderskeidelike voordele word uitgewys. Poolplasing beperkings, wat ontstaan as gevolg van die tipiese geringe nie-minimum fasegedrag van voertuigdinamika, word ontwikkel. ’n Gepaste generiese, voertuig onafhanklike navigasiebeheer algoritme vir gebruik saam met die binnelus-versnellingsbeheerders word voorgestel. Die voertuig word om ’n kinematies haalbare verwysingstrajek deur hierdie navigasie algoritme gereguleer. ’n Aantal fundamentele trajekte word voorgestel wat maklik gekombineer kan word om komplekse drie dimensionele maneuvers te vorm. Die veelsydigheid en funksionaliteit van die outoloods word deur simulasieresultate met ’n verskeidenheid voertuie en verwysingstrajekte gedemonstreer.

This thesis explores the potential impact of a World’s Fair on urban mobility in Los Angeles County by 2022. A brief historical account of World’s Fairs, and their impact on technological innovations in transportation will be given in conjunction with the development of transportation in Los Angeles. These accounts will help to contextualize an analysis of current plans to provide Los Angeles with transportation solutions, in light of the oversaturated automobile landscape in place today. Specifically, my research has revealed that the further development of light-speed rail systems paired alongside a mass adoption of autonomous vehicles would both alleviate contemporary transportation issues across Los Angeles County and accommodate the audience of international spectators that future mega-events may attract. Particular attention is paid to the Los Angeles World’s Fair for its ability to galvanize the resources and support that these transportation innovations require. I therefore conclude that the Los Angeles World Fair should direct its focus principally in support of these aforementioned technologies, as opposed to other less feasible transportations solutions such as the Hyperloop.

Un des buts de la recherche et du développement des systèmes de transport intelligents est d'augmenter le confort et la sécurité des passagers, tout en réduisant la consommation d'énergie, la pollution de l'air et le temps de déplacement. L'introduction de voitures complètement autonomes sur la voie publique nécessite la résolution d'un certain nombre de problèmes techniques et en particulier de disposer de modules de planification de trajectoire robustes. Ce travail de thèse s'inscrit dans ce cadre. Il propose une architecture modulaire pour la planification de trajectoire d'un véhicule autonome. La méthode permet de générer des trajectoires constituées de courbes interpolées adaptées à des environnements complexes comme des virages, des ronds-points, etc., tout en garantissant la sécurité et le confort des passagers. La prise en compte de l'incertitude des systèmes de perception, des limites physiques du véhicule, de la disposition des routes et des règles de circulation est aussi assurée dans le calcul de la trajectoire. L'algorithme est capable de modifier en temps réel la trajectoire prédéfinie de façon à éviter les collisions. Le calcul de la nouvelle trajectoire maintient les accélérations latérales à leur minimum, assurant ainsi le confort du passager. L'approche proposée a été évaluée et validée dans des environnements simulés et sur des véhicules réels. Cette méthode permet d'éviter les obstacles statiques et dynamiques repérés par le système de perception.Un système d'aide à la conduite pour le contrôle partagé basé sur cette architecture est introduit. Il prend en compte l'arbitrage, la surveillance et le partage de la conduite tout en maintenant le conducteur dans la boucle de contrôle. Il laisse le conducteur agir tant qu'il n'y a pas de danger et interagit avec le conducteur dans le cas contraire. L'algorithme se décompose donc en deux processus : 1) évaluation du risque et, s'il y a un risque avéré 2) partage du contrôle à l'aide de signaux haptiques via le volant.La méthode de planification de trajectoire présentée dans cette thèse est modulaire et générique. Elle peut être intégrée facilement dans toute architecture d'un véhicule autonome. / Developments in the Intelligent Transportation Systems (ITS) field show promising results at increasing passengers comfort and safety, while decreasing energy consumption, emissions and travel time. In road transportation, the appearance of automated vehicles is significantly aiding drivers by reducing some driving-associated tedious tasks. However, there is still a long way to go before making the transition between automated vehicles (i.e. vehicles with some automated features) and autonomous vehicles on public roads (i.e. fully autonomous driving), specially from the motion planning point of view. With this in mind, the present PhD thesis proposes the design of a generic modular architecture for automated vehicles motion planning. It implements and improves curve interpolation techniques in the motion planning literature by including comfort as the main design parameter, addressing complex environments such as turns, intersections and roundabouts. It will be able to generate suitable trajectories that consider measurements' incertitude from the perception system, vehicle’s physical limits, the road layout and traffic rules. In case future collision states are detected, the proposed approach is able to change---in real-time---the current trajectory and avoid the obstacle in front. It permits to avoid obstacles in conflict with the current trajectory of the ego-vehicle, considering comfort limits and developing a new trajectory that keeps lateral accelerations at its minimum. The proposed approach is tested in simulated and real urban environments, including turns and two-lane roundabouts with different radii. Static and dynamic obstacles are considered as to face and interact with other road actors, avoiding collisions when detected. The functional architecture is also tested in shared control and arbitration applications, focusing in keeping the driver in the control loop to addition the system's supervision over drivers’ knowledge and skills in the driving task. The control sharing advanced driver assistance system (ADAS) is proposed in two steps: 1) risk assessment of the situation in hand, based on the optimal trajectory and driving boundaries identified by the motion planning architecture and; 2) control sharing via haptic signals sent to the driver through the steering wheel. The approach demonstrates the modularity of the functional architecture as it proposes a general solution for some of today's unsolved challenges in the automated driving field.

<div>Class 8 trucks on average drive the most miles and consume the most fuel of any major vehicle category annually. Indiana specifically is the fifth busiest state for commercial freight traffic and moves $750 billion dollars of freight annually, and this number is expected to grow by 60% by 2040. Reducing fuel consumption for class 8 trucks would have a significant benefit on business and the proportional decrease in CO₂ would be exceptionally beneficial for the environment.</div><div><br></div><div>Platooning is one of the most important strategies for increasing class 8 truck fuel savings. Platooning alone can help trucks save upwards of 7% platoon average fuel savings on flat ground. However, it can be difficult for a platooning controller to maintain a desired truck separation during uncoordinated shifting events. Using a high-fidelity simulation model, it is shown that simultaneous shifting–having the follow truck shift whenever the lead truck shifts (unless shifting would cause its engine to overspeed or underspeed)–decreases maximum truck separation by 24% on a moderately challenging grade route and 40% on a heavy grade route.</div><div><br></div><div>Model Predictive Control (MPC) of the follow truck is considered as a means to reduce the distance the follow truck falls behind during uncoordinated shifting events. The result in simulation is a reduction in maximum truck separation of 1% on a moderately challenging grade route and 19% on a heavy grade route. However, simultaneous shifting largely alleviates the need for MPC for the sake of tracking for the follow truck.</div><div><br></div><div>A different MPC formulation is considered to dynamically change the desired set point for truck separation for routes through a strategy called Route Optimized Gap Growth (ROGG). The result in simulation is 1% greater fuel savings on a moderately challenging grade route and 7% greater fuel savings on a route with heavy grade for the follow truck.</div>

In the last couple of decades, there has been an unparalleled growth in number of people who can afford motorized vehicles. This is increasing the number of vehicles on roads at an alarming rate and existing infrastructure and conventional methods of traffic management are becoming inefficient both on highways and in urban areas. It is very important that our highways are up and running 24/7 as they not only provide a passage for human beings to move from one place to another, but also are the most important mode for intercity or international transfer of goods. There is an utter need of adapting the new world order, where daily processes are driven with the help of innovative technologies. It is highly likely that technological advancements like autonomous or connected vehicles, big data and the Internet of things can provide highway operators with a solution that might resolve unforeseeable challenges. This investigative exploratory research identifies and highlights the impact of new technological advancements in the automotive industry on highways and highway operators. The data for this research was collected on a Likert scale type online survey, from different organizations around the world (actively or passively involved in highway operations). The data was further tested for its empirical significance with non-parametric binomial and Wilcoxon signed rank tests, supported by a descriptive analysis. The results of this study are in line with theoretical and conceptual work done by several independent corporations and academic researchers. It is evident form the opinions of seasoned professionals that these technological advancements withhold the potential to resolve all potential challenges and revolutionize highway operations.

Veículos autônomos são objeto de crescente estudo em todo o mundo. Face à Engenharia de Transportes, é tema que deve provocar uma revolução nas próximas décadas, pois é concreta a tendência ao uso destes veículos na sociedade. Podem se citar como grandes beneficiados a segurança, a logística, o fluxo de trânsito, o meio ambiente e também os portadores de deficiências. Com o objetivo de fazer um veículo atingir um ponto com coordenadas conhecidas de forma autônoma, uma plataforma veicular terrestre em escala foi utilizada, a qual recebeu um sistema computacional micro controlado e tecnologias para proporcionar mobilidade através de motores elétricos para tração e servo-motores para direcionamento; posicionamento por satélite através de receptor GNSS e bússola eletrônica para orientação; sensoriamento por ultra-som para evitar colisões; e comunicação sem fio, a fim de se realizar remotamente monitoramento e instrução em tempo real através de um aplicativo para computador pessoal (PC). Foi desenvolvido um algoritmo de navegação que, fazendo uso dos recursos disponíveis, proporcionou autonomia ao veículo, de forma a navegar para pontos com coordenadas conhecidas sem controle humano. Os testes realizados visaram avaliar a capacidade de autonomia do veículo, a trajetória de navegação realizada e a acurácia de chegada aos pontos de destino. O veículo foi capaz de atingir os pontos em todos os testes realizados, sendo considerado funcional seu algoritmo de navegação e também os sistemas de mobilidade, posicionamento, sensoriamento e comunicação. / Autonomous vehicles are an on growing research target around the world. Face to Transports Engineering, it is a subject which is expected to make a revolution on the next decades. The great benefits are on security, logistic, traffic flow, environment and handicap. With the goal to make a vehicle navigate autonomously to known geodesics coordinates, a reduced scale terrestrial vehicular platform was used. This platform received a microcontrolled computational system and technologies to give it mobility, through electrical motors for traction and servo-motors for direction; satellite positioning, through a GNSS receiver and magnetic compass for orientation; ultrasound sensing in order to avoid collision; and wireless communication, in order to do remote monitoring and instruction at real time through a PC application. It was developed a navigation algorithm which, from the available resources, gave autonomy to the vehicle, in order to navigate to known geodesics coordinates without human control. The test set was intended to evaluate the autonomy capacity of the vehicle, the navigation trajectory that was done and the arrival accuracy to the destination points. The vehicle reached the destination points on all tests done, being evaluated as functional its navigation algorithm and also the mobility, positioning, sensing and communication systems.

Vehicular communication technologies, also called Vehicle-to-everything (V2X) systems, are expected to become common in the future, providing better effciency and safety in transportation. This envisioned large-scale deployment, however, critically depends on addressing some requirements. For example, to prevent abuse by drivers, messages exchanged among authorized vehicles must be authenticated, which implies the need of a Vehicular Public Key Infrastructure (VPKI). Unlike traditional Public Key Infrastructures (PKIs), though, VPKIs are also expected to preserve the drivers\' privacy; in particular, neither eavesdroppers or system entities should be able to easily identify or track the movements of vehicles using non-revoked certificates. One promising VPKI solution, which copes with such requirements and is among the main candidates for standardization in the United States and Europe, is Security Credential Management System (SCMS). In this thesis, aiming to address shortcomings identified in the SCMS architecture, three main contributions are provided. First, a mechanism for improving the exibility of revocation is described, allowing certificates and their owner\'s privacy to be temporarily revoked in an eficient manner; this functionality is useful, for example, in case a software malfunction is detected and a patch still needs to be released. Second, two birthday attacks against SCMS\'s certificate revocation process are detailed and then fixed, thus preventing the system\'s security degradation with the number of issued and revoked certificates. Finally, a method is proposed which simplifies SCMS\'s system architecture, removing the need for the so-called Linkage Authorities (LAs); this not only reduces the cost for SCMS\'s deployment, but also improves its security and privacy due to the removal of one potential point of failure/collusion. / Espera-se que as tecnologias de comunicação veicular, também chamadas de sistemas V2X (Vehicle-to-everything, em inglês), se tornem comuns no futuro, proporcionando melhor eficiência e segurança no transporte. Essa implantação planejada em larga escala, no entanto, depende criticamente de abordar alguns requisitos. Por exemplo, para prevenir abusos por motoristas, mensagens trocadas entre veículos autorizados devem ser autenticadas, o que implica na necessidade de uma Infraestrutura de Chaves Públicas Veicular (VPKI, do inglês, Vehicular Public Key Infrastructure). Diferente de Infraestruturas de Chaves Públicas (ICPs) tradicionais, porém, é esperado também que as VPKIs preservem a privacidade dos motoristas; em particular, que nem bisbilhoteiros, nem entidades do sistema possam identificar veículos ou rastrear seus movimentos facilmente utilizando certificados n~ao revogados. Uma solução promissora para VPKI, que lida com tais requisitos e está entre os principais candidatos para padronização nos Estados Unidos e na Europa é o Sistema de gerenciamento de credenciais de segurança (SCMS, do inglês, Security Credential Management System). Nessa dissertação, com o objetivo de abordar deficiências identificadas na arquitetura do SCMS, são fornecidas três contribuições principais. Primeiro, um mecanismo para melhorar a exibilidade do processo de revogação é descrito, permitindo que certificados e a privacidade de seus proprietários sejam revogados temporariamente de maneira eficiente; essa funcionalidade é útil, por exemplo, em caso de uma falha de software ser detectada e ser necessário a liberação de uma correção. Em segundo lugar, dois ataques do aniversário contra o processo de revogação do SCMS são detalhados e posteriormente corrigidos, assim, prevenindo a degradação de segurança do sistema com o número de certificados emitidos e revogados. Por fim, é proposto um método que simplifica a arquitetura do sistema SCMS, removendo a necessidade das chamadas Autoridades de Ligação (LAs, do inglês, Linkage Authorites); o que não só reduz o custo de implantação do SCMS, mas também aumenta sua segurança e privacidade devido à remoção de um potencial ponto de falha/conluio.

This dissertation focuses on real-time decision-making for large-scale domain search and object classification using Multiple Autonomous Vehicles (MAV). In recent years, MAV systems have attracted considerable attention and have been widely utilized. Of particular interest is their application to search and classification under limited sensory capabilities. Since search requires sensor mobility and classification requires a sensor to stay within the vicinity of an object, search and classification are two competing tasks. Therefore, there is a need to develop real-time sensor allocation decision-making strategies to guarantee task accomplishment. These decisions are especially crucial when the domain is much larger than the field-of-view of a sensor, or when the number of objects to be found and classified is much larger than that of available sensors. In this work, the search problem is formulated as a coverage control problem, which aims at collecting enough data at every point within the domain to construct an awareness map. The object classification problem seeks to satisfactorily categorize the property of each found object of interest. The decision-making strategies include both sensor allocation decisions and vehicle motion control. The awareness-, Bayesian-, and risk-based decision-making strategies are developed in sequence. The awareness-based approach is developed under a deterministic framework, while the latter two are developed under a probabilistic framework where uncertainty in sensor measurement is taken into account. The risk-based decision-making strategy also analyzes the effect of measurement cost. It is further extended to an integrated detection and estimation problem with applications in optimal sensor management. Simulation-based studies are performed to confirm the effectiveness of the proposed algorithms.

Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 2015. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student-submitted PDF version of thesis. Vita. / Includes bibliographical references (pages 203-213). / The capabilities of autonomous underwater vehicles (AUVs) and their ability to perform tasks both autonomously and adaptively are rapidly improving, and the desire to quickly and efficiently sample the ocean environment as Earth's climate changes and natural disasters occur has increased significantly in the last decade. As such, this thesis proposes to develop a method for single and multiple AUVs to collaborate autonomously underwater while autonomously adapting their motion to changes in their local environments, allowing them to sample and track various features of interest with greater efficiency and synopticity than previously possible with preplanned AUV or ship-based surveys. This concept is demonstrated to work in field testing on multiple occasions: with a single AUV autonomously and adaptively tracking the depth range of a thermocline or acousticline, and with two AUVs coordinating their motion to collect a data set in which internal waves could be detected. This research is then taken to the next level by exploring the problem of adaptively and autonomously tracking spatiotemporally dynamic underwater fronts and plumes using individual and autonomously collaborating AUVs. / by Stephanie Marie Petillo. / Ph. D.

Devido à grande importância do ambiente aquático sobre a vida humana e às dificuldades inerentes ao seu estudo e exploração, a aplicação de AUVs tem se mostrado bastante benéfica e seu uso vem crescendo ao longo dos anos. Este trabalho apresenta um estudo sobre o desenvolvimento de veículos autônomos submarinos para realização de missões oceanográficas, com foco nas características de seus sistemas embarcados que permitam atender melhor os requisitos desta aplicação. Analisando trabalhos publicados nos últimos anos pode-se notar uma grande quantidade de AUVs desenvolvidos ou adaptados para aplicações em oceanografia, com uma grande variedade de soluções aplicadas em seus diversos sistemas, visando a realização de diversos tipos de missões necessárias para tais estudos. Como estudo de caso, foi apresentada a adaptação do AUV Pirajuba, desenvolvido inicialmente como uma plataforma de testes hidrodinâmicos, para aplicação em missões de levantamento de dados para estudos oceanográficos. Para tal, foi necessário realizar uma série de modificações em seus subsistemas, permitindo a instalação de novos sensores e equipamentos para aumento da segurança nas operações em mar aberto. As modificações necessárias envolveram tanto o sistema hidromecânico do veículo, com instalação de novos módulos no casco, quanto no seu sistema embarcado, implicando no desenvolvimento de uma nova versão do sistema de hardware e uma atualização no software de controle. Tendo em vista esta necessidade, foi proposto um estudo dos requisitos da aplicação oceanográfica de AUVs e os impactos no seu desenvolvimento. Para isso, foi realizado um levantamento dos requisitos das principais aplicações oceanográficas e seus impactos no desenvolvimento dos veículos, envolvendo os sistemas hidromecânico, energia, navegação, comunicação e controle. Foi realizado também um estudo da arquitetura de controle CANARMES, desenvolvida para o AUV Pirajuba, envolvendo os requisitos de seu projeto e as principais características da arquitetura de controle, que serviu como base para a atualização do veículo para as novas aplicações. São apresentados os resultados obtidos em testes de campo realizados no litoral de Ubatuba - SP, nos quais foram feitas manobras com movimentação vertical com a aquisição de dados de diversos sensores oceanográficos, utilizados para o estudo de detecção de camadas finas. / Due to the great importance of the aquatic environment on human life and the inherent difficulties of its study and exploration, the application of AUVs has been shown to be very beneficial and its use has been growing over the years. This work presents a study on the development of autonomous submarine vehicles for the accomplishment of oceanographic missions, focusing on the characteristics of the embedded systems of these vehicles in order to better meet the application requirements. Analyzing published works in the last five years, it can be noticed a great amount of AUVs developed or adapted for applications in oceanography, with a great variety of solutions applied in their embedded systems, involving both hardware and software, aiming at the accomplishment of several types of missions necessary for such studies. As a case study, the adaptation of the AUV Pirajuba, initially developed as a platform for hydrodynamic tests, was presented for application in data collection missions for oceanographic studies. For this, it was necessary to make a series of modifications in its subsystems, allowing the installation of new sensors and equipment to increase the safety in the operations in the open sea. The necessary modifications involved both the vehicle\'s hydromechanical system, with the installation of new modules in the hull, and in its embedded system, requiring the development of a new version of the hardware system and an update in the control software. Due to this necessities, a study was proposed to better understand the requirements of AUVs for oceanographic application and the impacts on their development. For that, a survey was made of the requirements of the main oceanographic applications and their impacts on the development of the vehicles, involving the hydromechanical, energy, navigation, communication and control systems. A study of the CANARMES control architecture, developed for the Pirajuba AUV, was carried out, involving the requirements of its design and the main characteristics of the control architecture, which served as a basis for updating the vehicle for new applications. We present the results obtained in field tests conducted in the coastal area of Ubatuba - SP, Brazil, in which maneuvers were performed with vertical movement, while acquiring data from several oceanographic sensors, used for the study of thin layer detection.