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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Model Predictive Control for Heavy Duty Vehicle Platooning / Modellbaserad prediktionsreglering för tunga fordon i fordonståg

Kemppainen, Josefin January 2012 (has links)
The aim of platooning is to enable several vehicles to drive in a convoy while each vehicle is controlled autonomously in longitudinal direction. All vehicles in the platoon are equipped with WiFi and can therefore apply Vehicle-to-Vehicle (V2V) communication. As a result, a short intermediate distance between the vehicles can be maintained. Reduction of the aerodynamic drag is the result of the short distance, which in turn, reduces the consumed fuel. This thesis is a part of a larger project, consisting of two other theses that investigate estimation of the sensor data. Other scenarios that may arise with the platooning concept, e.g. packet losses and time synchronization of the different sensors are also analyzed. The purpose of this master thesis is to develop and evaluate a Model Predictive Control (MPC) in the concept of platooning. The main focus lies on implementation of two types of MPC, centralized and distributed, and later on integration with the other two subsystems is performed. Results from the MPC itself are evaluated, principally in terms of fuel con- sumption and computational demand. The major part of the results are based on the complete system as one unit and covers different test scenarios such as WiFi loss and non-transmitting vehicle entering the platoon. A comparison of how much energy that is consumed by the engine between an HDV driving with its cruise control and an HDV driving in a platoon has been performed. With an intermediate distance of 10 meters, driving with varying velocity and ideal signals the energy consumption got reduced with an average of 11%. / Syftet med platooning är att flera tunga fordon kör tätt efter varandra i ett fordonståg. Varje fordon regleras autonomt i longitudinell riktning och är utrustad med WiFi. Detta bidrar till att fordonen kan kommunicera med varandra och denna kommunikation, även kallad Vehicle-to-Vehicle (V2V) - communication, leder till att det relativa avståndet mellan fordonen kan minskas, vilket i sin tur leder till minskat luftmotstånd och därmed minskad bränsleförbrukning. Detta examensarbete är en del av ett större projekt som består av ytterligare två examensarbeten. De andra två hanterar estimeringen av sensordata samt behandlar förlorat sensordata och tidssynkronisering av de olika sensorerna som används. Syftet med detta examensarbete är att utveckla och utvärdera en MPC regu- lator i platooning sammanhang. Huvudfokuset ligger på implementeringen, både centraliserad och distribuerad MPC, och integreringen med de två andra delsystemen. Resultaten från enbart MPC utvärderas i termer av bränsleförbrukning och även beräkningskapactiet, då MPC är känt för att vara väldigt beräkningskrävan- de och är ofta en begränsning för hårdvaran. Den största delen av resultaten är baserade på hela systemet och täcker olika scenarion som exempelvis dålig WiFi uppkoppling och att icke−sändande fordon intar platoonen. En jämförelse av hur mycket energi motorn förbrukade har gjorts mellan ett tungt fordon som kör med farthållaren påslagen och ett tungt fordon som kör i en platoon. Med ett relativt avstånd på 10 meter, varierande hastighet och icke brusiga signaler kan bränsleförbrukning minskas med ett medel på approximativt 11%.
12

Modeling Automated Highway System Guideway Operations

Siess, Eric Joseph 04 February 1998 (has links)
The purpose of this research is to explore the operational characteristics of a Maglev-based Automated Highway System and how it would interact with freeway operations. The extension of traditional traffic flow phenomenon, including weaving, merging, and stopping distance, into the automated system is looked at. These are also extended into platoon operations and their effect on such properties as gap control and ultimately the capacity of such a system. The ability to incorporate an AHS system into the existing Interstate Highway System is investigated. This includes placing the magways in the right-of-way of the highway system and interfacing the AHS with the existing freeways. A model is developed and run to simulate the assignment of traffic between the freeway and the guideway links. Both operational concepts of user equilibrium and system optimal conditions are explored, and equations are found to estimate the amount of traffic which can be found on the links based on the total traffic volume. / Master of Science
13

Effects of Communication Delay and Kinematic Variation in Vehicle Platooning

Emmons, Megan R. 01 August 2013 (has links)
Vehicle platoons are efficient, closely-spaced groups of robotically controlled vehicles which travel at high speeds down the road, similar to carts in a train. Within this thesis, a promising control algorithm for vehicle platooning is explored. The control algorithm was previously demonstrated in a sterile setting which significantly reduced the challenges facing full-scale implementation of platoons, most notably loss of shared data and imprecision within the data. As found within this work, transmission loss and imprecise position, velocity, and acceleration data significantly degraded the control algorithm's performance. Vehicles in the platoon became more closely spaced, changed speeds more frequently, and expended far more energy than necessary. Introducing a measure of each following vehicle's position with respect to the lead vehicle into the control algorithm noticeably reduced platoon contraction. Adjusting the control algorithm's responsiveness based on what data was successfully received reduced the speed-variations by vehicles. Finally, using past behavior to predict the next acceleration reduced the energy used by each vehicle. Combining these modifications with a model of the proposed communication scheme shows platoons of up to 25 vehicles are feasible.
14

Visualizing simulations of heavy duty vehicle platooning : A participatory design study

Strid, Erik January 2020 (has links)
Research in automatic control has enabled trucks to use adaptive cruise control to drive very close to each other and form platoons. This reduces drag and improves efficiency by lowering fuel consumption. A central challenge to understanding the formation of these platoons is that not all trucks are emerging from the same origin or reaching the same destination; they only share parts of their joint trip. This study uses participatory design methodologies to create a design for an interactive visualization system to enable researchers to study the formation of platoons in simulated scenarios. Three transport researchers participated in interviews and a set of two workshops to establish their needs and formulate tasks that would improve their understanding of the simulations. The main research-through-design question was “when do platoons form and how large are they?” To forward and ground the discussion, I developed a prototype with increasing fidelity after each round of participatory design. The interface consists four panels: 1) a spatial panel that contains a map view; 2) a temporal panel with context and focus timelines: 3) an adaptation panel with details on inter-truck relationships; and 4) a filtering panel with a parallel coordinate system. The results indicate a need for a flexible interactive visualization system that enables researchers to study how trucks are affected by plan recalculations and how they adapt to their partners influencing the costs and benefits of platooning. / Forskning inom reglerteknik och fordonsstyrning har gett lastbilar och andra tunga fordon möjlighet använda adaptiv farthållning till att köra med ett litet mellanrum och bilda vägkolonner. De kan då utnyttja vindsuget från fordonet framför och på så vis sänka bränsleförbrukningen. En central utmaning i skapandet av dessa kolonner är att fordonen inte har gemensamma startpunkter och destinationer. De delar i de flesta fall endast stycken av sin rutt med andra fordon, och turerna behöver då sammanfalla i tid. Denna studie använder deltagande designmetodik för att designa ett interaktivt visualiseringsverktyg som kan hjälpa forskare att studera skapandet av lastbilskolonner i simulerade scenarion. Tre transportforskare deltog i intervjuer och två cykler av workshops för att synliggöra och formulera arbetsuppgifter som kunde förbättra deras förståelse av simulationerna. Den primära deltagande design-frågan var “när bildas kolonner och hur stora är de?” För att förankra och driva diskussionen kring designen framåt utvecklades en prototyp som viderutvecklades efter varje deltagande designcykel. Interfacet i den resulterande prototypen och består av fyra paneler: 1) en geografisk panel som innehåller en kartvy; 2) en panel med tidslinjer för både fokus och kontext; 3) en anpassningspanel med detaljer på fordonens relationer; och 4) en filtreringspanel med ett parallellt koordinatsystem. Resultatet av studien indikerar ett behov ett flexibel visuellt analysverktyg som tillåter forskare att studera hur fordonen påverkas av förändringar i resplaner och vilken anpassning som krävs för att möta upp andra fordon för kolonnbildning.
15

Trajectory Tracking Control of Unmanned Ground Vehicles using an Intermittent Learning Algorithm

Gundu, Pavan Kumar 21 August 2019 (has links)
Traffic congestion and safety has become a major issue in the modern world's commute. Congestion has been causing people to travel billions of hours more and to purchase billions of gallons of fuel extra which account to congestion cost of billions of dollars. Autonomous driving vehicles have been one solution to this problem because of their huge impact on efficiency, pollution, and human safety. Also, extensive research has been carried out on control design of vehicular platoons because a further improvement in traffic throughput while not compromising the safety is possible when the vehicles in the platoon are provided with better predictive abilities. Motion control is a key area of autonomous driving research that handles moving parts of vehicles in a deliberate and controlled manner. A widely worked on problem in motion control concerned with time parameterized reference tracking is trajectory tracking. Having an efficient and effective tracking algorithm embedded in the autonomous driving system is the key for better performance in terms of resources consumed and tracking error. Many tracking control algorithms in literature rely on an accurate model of the vehicle and often, it can be an intimidating task to come up with an accurate model taking into consideration various conditions like friction, heat effects, ageing processes etc. And typically, control algorithms rely on periodic execution of the tasks that update the control actions, but such updates might not be required, which result in unnecessary actions that waste resources. The main focus of this work is to design an intermittent model-free optimal control algorithm in order to enable autonomous vehicles to track trajectories at high-speeds. To obtain a solution which is model-free, a Q-learning setup with an actor-network to approximate the optimal intermittent controller and a critic network to approximate the optimal cost, resulting in the appropriate tuning laws is considered. / Master of Science / A risen research effort in the area of autonomous vehicles has been witnessed in the past few decades because these systems improve safety, comfort, transport time and energy consumption which are some of the main issues humans are facing in the modern world’s highway systems. Systems like emergency braking, automatic parking, blind angle vehicle detection are creating a safer driving environment in populated areas. Advanced driver assistance systems (ADAS) are what such kind of systems are known as. An extension of these partially automated ADAS are vehicles with fully automated driving abilities, which are able to drive by themselves without any human involvement. An extensively proposed approach for making traffic throughput more efficient on existing highways is to assemble autonomous vehicles into platoons. Small intervehicle spacing and many vehicles constituting each platoon formation improve the traffic throughput significantly. Lately, the advancements in computational capabilities, in terms of both algorithms and hardware, communications, and navigation and sensing devices contributed a lot to the development of autonomous systems (both single and multiagent) that operate with high reliability in uncertain/dynamic operating conditions and environments. Motion control is an important area in the autonomous vehicles research. Trajectory-tracking is a widely studied motion control scenario which is about designing control laws that force a system to follow some time-dependent reference path and it is important to have an effective and efficient trajectory-tracking control law in an autonomous vehicle to reduce the resources consumed and tracking error. The goal of this work is to design an intermittent model-free trajectory tracking control algorithm where there is no need of any mathematical model of the vehicle system being controlled and which can reduce the controller updates by allowing the system to evolve in an open loop fashion and close the loop only when an user defined triggering condition is satisfied. The approach is energy efficient in that the control updates are limited to instances when they are needed rather than unnecessary periodic updates. Q-learning which is a model-free reinforcement learning technique is used in the trajectory tracking motion control algorithm to make the vehicles track their respective reference trajectories without any requirement of their motion model, the knowledge of which is generally needed when dealing with a motion control problem. The testing of the designed algorithm in simulations and experiments is presented in this work. The study and development of a vehicle platform in order to perform the experiments is also discussed. Different motion control and sensing techniques are presented and used. The vehicle platform is shown to track a reference trajectory autonomously without any human intervention, both in simulations and experiments, proving the effectiveness of the proposed algorithm.
16

Modeling Human And Machine-In-The-Loop In Car-Following Theory

Fadhloun, Karim 29 October 2019 (has links)
Most phenomena in engineering fields involve physical variables that can potentially be predicted using simple or complex mathematical models. However, traffic engineers and researchers are faced with a complex challenge since they have to deal with the human element. For instance, it can be stated that the biggest challenge facing researchers in the area of car-following theory relates to accounting for the human-in-the-loop while modeling the longitudinal motion of the vehicles. In fact, a major drawback of existing car-following models is that the human-in-the-loop is not modeled explicitly. This is specifically important since the output from car-following models directly impacts several other factors and measures of effectiveness, such as vehicle emissions and fuel consumption levels. The main contribution of this research relates to modeling and incorporating, in an explicit and independent manner, the human-in-the-loop component in car-following theory in such a way that it can be either activated or deactivated depending on if a human driver is in control of the vehicle. That would ensure that a car-following model is able to reflect the different control and autonomy levels that a vehicle could be operated under. Besides that, this thesis offers a better understanding of how humans behave and differ from each other. In fact, through the implementation of explicit parameters representing the human-in-the-loop element, the heterogeneity of human behavior, in terms of driving patterns and styles, is captured. To achieve its contributions, the study starts by modifying the maximum acceleration vehicle-dynamics model by explicitly incorporating parameters that aim to model driver behavior in its expression making it suitable for the representation of typical acceleration behavior. The modified variant of the model is demonstrated to have a flexible shape that allows it to model different types of variations that drivers can generate, and to be superior to other similar models in that it predicts more accurate acceleration levels in all domains. The resulting model is then integrated in the Rakha-Pasumarthy-Adjerid car-following model, which uses a steady-state formulation along with acceleration and collision avoidance constraints to model the longitudinal motion of vehicles. The validation of the model using a naturalistic dataset found that the modified formulation successfully integrated the human behavior component in the model and that the new formulation decreases the modeling error. Thereafter, this dissertation proposes a new car-following model, which we term the Fadhloun-Rakha model. Even though structurally different, the developed model incorporates the key components of the Rakha-Pasumarthy-Adjerid model in that it uses the same steady state formulation, respects vehicle dynamics, and uses very similar collision-avoidance strategies to ensure safe following distances between vehicles. Besides offering a better fit to empirical data, the Fadhloun-Rakha model is inclusive of the following characteristics: (1) it models the driver throttle and brake pedal input; (2) it captures driver variability; (3) it allows for shorter than steady-state following distances when following faster leading vehicles; (4) it offers a much smoother acceleration profile; and (5) it explicitly captures driver perception and control inaccuracies and errors. Through a quantitative and qualitative evaluation using naturalistic data, the new model is demonstrated to outperform other state-of-the-practice car-following models. In fact, the model is proved to result in a significant decrease in the modeling error, and to generate trajectories that are highly consistent with the observed car-following behavior. The final part of this study investigates a case in which the driver is excluded and the vehicles are operating in a connected environment. This section aims to showcase a scenario in which the human-in-the-loop is deactivated through the development of a platooning strategy that governs the motion of connected cooperative multi-vehicle platoons. / Doctor of Philosophy / Even though the study of the longitudinal motion of vehicles spanned over several decades leading to the development of more precise and complex car-following models, an important aspect was constantly overlooked in those models. In fact, due to the complexity of modeling the human-in-the-loop, the vehicle and the driver were almost always assumed to represent a single entity. More specifically, ignoring driver behavior and integrating it to the vehicle allowed avoiding to deal with the challenges related to modeling human behavior. The difficulty of mathematically modeling the vehicle and the driver as two independent components rather than one unique system is due to two main reasons. First, there are numerous car models and types that make it difficult to determine the different parameters impacting the performance of the vehicle as they differ from vehicle to vehicle. Second, different driving patterns exist and the fact that they are mostly dependent on human behavior and psychology makes them very difficult to replicate mathematically. The research presented in this thesis provides a comprehensive investigation of the human-in-the-loop component in car-following theory leading to a better understanding of the human-vehicle interaction. This study was initiated due to the noticeable overlooking of driver behavior in the existing literature which, as a result, fails to capture the effect of human control and perception errors.
17

Aerodynamisk analys av platooning : Hur olika fordonsformer, hastigheter, avstånd och antal fordon påverkar energibesparingen i fordonskolonner

Rickardsson, Alve, Olajos, William January 2024 (has links)
Rapporten behandlar en analys av de aerodynamiska aspekterna av fordonskonceptet platooning. Syftet är att avgöra hur olika aspekter påverkar luftmotståndet och i slutändan energibesparingen av att färdas i en fordonskolonn. Aspekterna som studeras är olika fordonsformer, hastigheter, avstånd och antal fordon i kolonnen. För att besvara frågeställningarna har en litteraturstudie genomförts där femton källor har analyserats. För att underbygga vissa av frågeställningarna ytterligare har även en förenklad beräkningsströmningsdynamik-analys (CFD) genomförts i 2D. CFD-analysen är gjord på en personbil av typen Volvo V60. Energibesparingen har beräknats utifrån en jämförelse med om samma bil hade färdats isolerat.  CFD-simuleringen genomfördes i tre steg. I det första steget varierades hastigheten för en given kolonn för att kunna avgöra hastighetens inverkan på energibesparingen. Därefter varierades fordonsavståndet för att avgöra dess inverkan och i sista steget varierades fordonsantalet. Slutsatserna som kan dras från arbetet utifrån den ställda frågeställningen är att i fordonskolonner med fordon av olika form ska fordonen med mest lik form placeras i anslutning till varandra så att de bildar en normalfördelningsform där de största fordonen placeras i mitten och de minsta i början och slutet av kolonnen. Slutsatsen drogs också att ur ett aerodynamiskt perspektiv ökar varje tillagt fordon till en kolonn energibesparingarna, dock är detta inte genomförbart ur ett trafiksäkerhetsperspektiv för ett oändligt antal fordon. Vidare drogs slutsatserna att de mellersta bilarna, det vill säga de som har en bil framför och bakom sig står för de största relativa energibesparingen vid små fordonsavstånd. Slutligen drogs de generella slutsatserna att minsta möjliga avstånd, och högsta möjliga hastighet gör att de relativa energibesparingarna blir så stora som möjligt.
18

Platoon Coordination of Electric Trucks at a Charging Station

Björklund, Elin, Lindstedt, Ebba January 2022 (has links)
Electric trucks and platooning technology are expected to be part of the transportation system in the near future. Therefore, it is important to develop platoon coordination strategies and study the potential of platooning for when trucks are electric. In this paper, we study the platoon coordination problem at a single charging station where electric trucks can charge while they wait for other trucks to form platoons with.We assume all trucks to have identical routes after the charging station. The objective is to maximize the total reward of all trucks, including the platooning profit and cost of waiting.Moreover, the trucks have waiting time constraints to respect their mission deadlines and charging time constraints to make sure they can travel between the hub and destination without running out of battery. The energy consumption is decreased when driving as a follower truck in a platoon, which decreases the minimum charging time for the truck. We formulate the platoon coordination problem of electric trucks as a linear integer optimization problem. To evaluate the method, it was compared to a simpler coordination method. The savings from platooning with electric vehicles, using both coordination methods, were also compared to platooning with diesel trucks. The results showed that platooning with electric vehicles can save up to 10% of the driving cost and therefore have significant economic benefits. It was also shown that the method has an acceptable computational efficiency for real-time coordination. / Inom en snar framtid förväntas elektriska lastbilar och platooning vara en del av transportsystemet. Det är därför viktigt att utveckla strategier för platoonkoordinering och undersöka potentialen av platooning med elektriska lastbilar. I det här pappret studerar vi ett platoonkoordineringsproblem med en gemensam startpunkt och en gemensam slutpunkt för alla lastbilar. Startpunkten är en laddningsstation där lastbilarna kan kombinera laddning med att vänta in andra lastbilar att forma platooner med. Lastbilarna i systemet har även samma rutt mellan de två punkterna. Målet är att maximera den totala vinsten för alla lastbilar, med hänsyn till både platooningvinsten och kostnaden för att vänta. Utöver det har lastbilarna begränsad väntetid för att hålla sina deadlines. Vi behöver även ta hänsyn till lastbilarnas laddningstider då de behöver ha tillräckligt med laddning för att åka hela resan från startpunkt till slutdestination. Energikonsumtionen minskar när en lastbil åker som följare vilket minskar den minimala laddningstiden som behövs för att åka hela sträckan. Vi formulerar koordineringsproblemet med elektriska lastbilar som ett linjärt heltalsoptimeringsproblem. För att utvärdera metoden jämfördes den med en enklare koorineringsmetod. Besparingarna från platooning med elektriska lastbilar, med båda koordineringsmetoderna, jämfördes även med platooning med diesellastbilar. Resultatet visade att platooning med ellastbilar kan spara upp till 10% av körkostnaderna och har därför betydande ekonomiska fördelar. Det visades också att metoden har en acceptabel beräkningseffektivitet för koordinering i realtid. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm
19

Cooperative Mobility in Urban Environments

Hardes, Tobias 15 July 2024 (has links)
Platooning ermöglicht koordiniertes Fahren in Konvois, um Straßenauslastung, Emissionen, Verkehrsfluss und Sicherheit zu optimieren. Obwohl ursprünglich für Autobahnen entwickelt, könnten besonders urbane Gebiete, die mit Luftverschmutzung, Unfällen und Staus konfrontiert sind, von Platooning profitieren. Bisherige Platooning-Konzepte sind jedoch nicht speziell für urbane Umgebungen ausgelegt. In dieser Dissertation untersuchen wir erstmalig die Vorteile und Herausforderungen des urbanen Platoonings, speziell in Bezug auf Intra- und Inter-Platoon Kommunikation und Koordination in urbanen Gebieten. Zu diesem Zweck evaluieren wir die Realisierbarkeit von Platooning in urbanen Umgebungen unter Beachtung von Mobilitäts- und drahtlosen Kommunikationsaspekten. Unser Ansatz zur dynamischen Bildung von Platoons bringt deutliche Verbesserungen hinsichtlich der Fahrzeit und des Kraftstoffverbrauchs im urbanen Kontext im Vergleich zum konventionellen Fahren. Ferner zeigen wir die Limitationen der Nutzung von reiner IEEE 802.11p-basierten Kommunikation und zeigen die Schwächen von Vehicular Visible Light Communication (V-VLC) in urbanen Umgebungen, verglichen mit dessen vorteilhafter Anwendung auf Autobahnen. Zweitens stellen wir innovative Strategien für die Kommunikation innerhalb eines Platoons vor. Das Ergebnis ist LUNA, ein neuartiger Ansatz, der Beamforming und Full-Duplex Relaying (FDR) für urbanes Platooning kombiniert. Unsere Untersuchungen zeigen, dass LUNA im Gegensatz zu traditionellen Ansätzen wie V-VLC, sowohl für Autobahn- als auch für urbane Szenarien geeignet ist, mit einer PDR von 100 % und nahezu keinem Paketverlust in urbanen Umgebungen. Drittens untersuchen wir das Potenzial urbaner Infrastruktur zur Koordination zwischen Platoons in Smart Cities. Wir zeigen, dass der opportunistische Einsatz von unbemannten Luftfahrzeugen (UAVs) zur Weiterleitung drahtloser Übertragungen von Fahrzeugen nicht nur gewinnbringender ist als ein dedizierter UAV-Einsatz, sondern auch den Kanalzugriff über mehrere Platoons koordinieren kann. Dies reduziert den Paketverlust im Vergleich zu Szenarien ohne UAVs erheblich. Diese Arbeit demonstriert die Machbarkeit von Urban Platooning, stellt Methoden für zuverlässige drahtlose Kommunikation vor und legt damit einen Grundstein für zukünftige Forschungen.:Abstract Kurzfassung 1 Introduction 2 Fundamentals 2.1 Control Systems............................... 12 2.2 Communication in Vehicular Networks ................. 16 2.3 Intra-Platoon Communication ...................... 31 2.4 Unmanned Aerial Vehicles in Smart Cities .................. 33 3. Urban Platoon Formation 39 3.1 State of the Art ............................... 42 3.2 Platoon Formation ............................. 44 3.3 Simulative Evaluation ........................... 48 3.4 Lessons Learned............................... 52 4 Wireless Communication Challenges for Urban Platooning 53 4.1 State of the Art ............................... 56 4.2 Heterogeneous Communication Protocols using Vehicular Visible Light Communication(V-VLC).......................... 57 4.3 Simulative Evaluation ........................... 59 4.4 Lessons Learned............................... 67 5 Beamforming for Platoons 71 5.1 State of the Art ............................... 74 5.2 Experimental Validation .......................... 76 5.3 Simulative Evaluation ........................... 79 5.4 Lessons Learned............................... 87 6 Full-Duplex Relaying and Beamforming for Platoons 89 6.1 State of the Art:Full-Duplex Relaying ................. 92 6.2 The Need for Multi-Hop Relaying Approaches for Platoons . . . . . 94 6.3 LUNA (full duplex relaying with beamforming) . . . . . . . . . . . 94 6.4 Simulative Evaluation: Freeway Platooning . . . . . . . . . . . . . . 96 6.5 Lessons Learned:Freeway Platooning ................. 104 6.6 State of the Art: Full-Duplex Relaying for Urban Environments . . 105 6.7 Simulative Evaluation: Urban Platooning . . . . . . . . . . . . . . . 106 6.8 Lessons Learned:Urban Platooning................... 112 7 Utilization of Unmanned Aerial Vehicles (UAVs) in Cooperative Urban Wireless Networks 117 7.1 An Open-Source Fully Modular Multi Unmanned Aerial Vehicle (UAV) Simulation Framework........................... 122 7.2 State of the Art: Unmanned Aerial Vehicles (UAVs) in Wireless Networks ..................................... 133 7.3 Opportunistic Relaying........................... 135 7.4 Simulative Evaluation ........................... 136 7.5 Influences on Opportunistic Relay Success . . . . . . . . . . . . . . . 139 7.6 Optimized Missions vs. Opportunistic Relaying . . . . . . . . . . . . 147 7.7 Lessons Learned............................... 148 8 Unmanned Aerial Vehicle (UAV) Supported Urban Platooning 151 8.1 State of the Art ............................... 154 8.2 Inter-Platoon Channel Access Coordination with Unmanned Aerial Vehicles(UAVs) ............................... 154 8.3 Simulative Evaluation ........................... 157 8.4 Lessons Learned............................... 159 9 Conclusion 161 Bibliography 177 / Platooning empowers vehicles to drive in coordinated convoys, improving road utilization, emissions, traffic flow, and road safety. To realize platooning, reliable wireless communication is required. Although designed for freeways, platooning could be especially beneficial in urban environments facing pollution, accidents, and congestion challenges. However, current system designs for platooning are not tailored to the characteristics of urban environments. This dissertation addresses the benefits and challenges of wireless communication among platooning vehicles (intra-platoon communication) and the coordination of multiple platoons (inter-platoon coordination) for the first time with a dedicated focus on urban environments. For this, we first evaluate the viability of platooning in urban environments, considering mobility and wireless communication aspects. Using our approach for dynamic platoon formation, we show that urban platooning massively enhances travel time and fuel consumption compared to traditional driving. Additionally, we demonstrate the limitations of solely using Radio Frequency (RF) communication and underscore the shortcomings of Vehicular Visible Light Communication (V-VLC) in urban environments compared to its beneficial use on freeways. Second, we present novel strategies for intra-platoon communication, resulting in LUNA, a novel approach combining beamforming and Full-Duplex Relaying (FDR) for urban platooning. Our evaluation shows that LUNA, unlike traditional approaches such as V-VLC, is appropriate for freeway and urban scenarios, achieving a 100 % PDR on freeways and negligible packet loss in an urban environment. Third, we investigate the potential of urban infrastructure for inter-platoon coordination in future smart cities. We show that an opportunistic use of Unmanned Aerial Vehicles (UAVs) to relay wireless transmissions of vehicles outperforms a dedicated UAV deployment and can further coordinate wireless channel access, substantially reducing packet loss compared to scenarios without UAVs. In this thesis, we demonstrate the feasibility of urban platooning and present approaches for reliable wireless communication, thereby providing a step towards its realization and the foundation for future research.:Abstract Kurzfassung 1 Introduction 2 Fundamentals 2.1 Control Systems............................... 12 2.2 Communication in Vehicular Networks ................. 16 2.3 Intra-Platoon Communication ...................... 31 2.4 Unmanned Aerial Vehicles in Smart Cities .................. 33 3. Urban Platoon Formation 39 3.1 State of the Art ............................... 42 3.2 Platoon Formation ............................. 44 3.3 Simulative Evaluation ........................... 48 3.4 Lessons Learned............................... 52 4 Wireless Communication Challenges for Urban Platooning 53 4.1 State of the Art ............................... 56 4.2 Heterogeneous Communication Protocols using Vehicular Visible Light Communication(V-VLC).......................... 57 4.3 Simulative Evaluation ........................... 59 4.4 Lessons Learned............................... 67 5 Beamforming for Platoons 71 5.1 State of the Art ............................... 74 5.2 Experimental Validation .......................... 76 5.3 Simulative Evaluation ........................... 79 5.4 Lessons Learned............................... 87 6 Full-Duplex Relaying and Beamforming for Platoons 89 6.1 State of the Art:Full-Duplex Relaying ................. 92 6.2 The Need for Multi-Hop Relaying Approaches for Platoons . . . . . 94 6.3 LUNA (full duplex relaying with beamforming) . . . . . . . . . . . 94 6.4 Simulative Evaluation: Freeway Platooning . . . . . . . . . . . . . . 96 6.5 Lessons Learned:Freeway Platooning ................. 104 6.6 State of the Art: Full-Duplex Relaying for Urban Environments . . 105 6.7 Simulative Evaluation: Urban Platooning . . . . . . . . . . . . . . . 106 6.8 Lessons Learned:Urban Platooning................... 112 7 Utilization of Unmanned Aerial Vehicles (UAVs) in Cooperative Urban Wireless Networks 117 7.1 An Open-Source Fully Modular Multi Unmanned Aerial Vehicle (UAV) Simulation Framework........................... 122 7.2 State of the Art: Unmanned Aerial Vehicles (UAVs) in Wireless Networks ..................................... 133 7.3 Opportunistic Relaying........................... 135 7.4 Simulative Evaluation ........................... 136 7.5 Influences on Opportunistic Relay Success . . . . . . . . . . . . . . . 139 7.6 Optimized Missions vs. Opportunistic Relaying . . . . . . . . . . . . 147 7.7 Lessons Learned............................... 148 8 Unmanned Aerial Vehicle (UAV) Supported Urban Platooning 151 8.1 State of the Art ............................... 154 8.2 Inter-Platoon Channel Access Coordination with Unmanned Aerial Vehicles(UAVs) ............................... 154 8.3 Simulative Evaluation ........................... 157 8.4 Lessons Learned............................... 159 9 Conclusion 161 Bibliography 177
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The operational and safety effects of heavy duty vehicles platooning

Alzahrani, Ahmed 01 January 2019 (has links)
Abstract Although researchers have studied the effects of platooning, most of the work done so far has focused on fuel consumption. There are a few studies that have targeted the impact of platooning on the highway operations and safety. This thesis focuses on the impact of heavy-duty vehicles (HDVs) platooning on highway characteristics. Specifically, this study aims at evaluating the effects of platooning of HDVs on capacity, safety, and CO2 emissions. This study is based on a hypothetical model that was created using the VISSIM software. VISSIM is a powerful simulation software designed to mimic the field traffic flow conditions. For model validity, the model outputs were compared with recommended values from guidelines such as the Highway Capacity Manual (HCM) (Transportation Research Board, 2016). VISSIM was used to obtain the simulation results regarding capacity. However, in addition to VISSIM, two other software packages were used to obtain outputs that cannot be assessed in VISSIM. MOVES and SSAM are two simulation software packages that were used for emission and safety metrics, respectively. Both software packages depended on input from VISSIM for analysis. It was found that with the presence of HDVs in the model, the capacity, the emission of CO2, and the safety of the roadway would improve positively. A capacity of 4200 PCE/h/ln could be achieved when there are enough HDVs in platoons. Furthermore, more than 3% of the traffic flow emission of CO2 reduction is possible when 100% of the HDVs used in the model are in platoons. In addition to that, a reduction of more than 75% of the total number of conflicts might be obtained. Furthermore, with the analysis of the full factorial method and the Design of Experiment (DOE) conducted by using Excel and Minitab respectively, it was possible to investigate the impact of the platoons’ factors on the highway parameters. Most of these factors affect the parameters significantly. However, the change in the desired speed was found to insignificantly affect the highway parameters, due to the high penetration rate. Keywords: VISSIM, MOVES, SSAM, COM-interface, HDVs, Platooning, Number of Conflicts

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