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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.
51

Quantifying Vision Zero: Crash avoidance in rural and motorway accident scenarios by combination of ACC, AEB, and LKS projected to German accident occurrence

Stark, Lukas, Düring, Michael, Schoenawa, Stefan, Maschke, Jan Enno, Do, Cuong Manh 29 September 2020 (has links)
Objective: The Vision Zero initiative pursues the goal of eliminating all traffic fatalities and severe injuries. Today’s advanced driver assistance systems (ADAS) are an important part of the strategy toward Vision Zero. In Germany in 2018 more than 26,000 people were killed or severely injured by traffic accidents on motorways and rural roads due to road accidents. Focusing on collision avoidance, a simulative evaluation can be the key to estimating the performance of state-of-the-art ADAS and identifying resulting potentials for system improvements and future systems. This project deals with the effectiveness assessment of a combination of ADAS for longitudinal and lateral intervention based on German accident data. Considered systems are adaptive cruise control (ACC), autonomous emergency braking (AEB), and lane keeping support (LKS). Methods: As an approach for benefit estimation of ADAS, the method of prospective effectiveness assessment is applied. Using the software rateEFFECT, a closed-loop simulation is performed on accident scenario data from the German In-Depth Accident Study (GIDAS) precrash matrix (PCM). To enable projection of results, the simulative assessment is amended with detailed single case studies of all treated cases without PCM data. Results: Three categories among today’s accidents on German rural roads and motorways are reported in this study: Green, grey, and white spots. Green spots identify accidents that can be avoided by state-of-the-art ADAS ACC, AEB, and LKS. Grey spots contain scenarios that require minor system modifications, such as reducing the activation speed or increasing the steering torque. Scenarios in the white category cannot be addressed by state-of-the-art ADAS. Thus, which situations demand future systems are shown. The proportions of green, grey, and white spots are determined related to the considered data set and projected to the entire GIDAS. Conclusions: This article describes a systematic approach for assessing the effectiveness of ADAS using GIDAS PCM data to be able to project results to Germany. The closed-loop simulation run in rateEFFECT covers ACC, AEB, and LKS as well as relevant sensors for environment recognition and actuators for longitudinal and lateral vehicle control. Identification of green spots evaluates safety benefits of state-of-the-art level 0–2 functions as a baseline for further system improvements to address grey spots. Knowing which accidents could be avoided by standard ADAS helps focus the evolution of future driving functions on white spots and thus aim for Vision Zero.
52

Crash Prediction and Collision Avoidance using Hidden Markov Model

Prabu, Avinash 08 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Automotive technology has grown from strength to strength in the recent years. The main focus of research in the near past and the immediate future are autonomous vehicles. Autonomous vehicles range from level 1 to level 5, depending on the percentage of machine intervention while driving. To make a smooth transition from human driving and machine intervention, the prediction of human driving behavior is critical. This thesis is a subset of driving behavior prediction. The objective of this thesis is to predict the possibility of crash and implement an appropriate active safety system to prevent the same. The prediction of crash requires data of transition between lanes, and speed ranges. This is achieved through a variation of hidden Markov model. With the crash prediction and analysis of the Markov models, the required ADAS system is activated. The above concept is divided into sections and an algorithm was developed. The algorithm is then scripted into MATLAB for simulation. The results of the simulation is recorded and analyzed to prove the idea.
53

Leveraging Vehicle-to-Infrastructure Communications for Adaptive Traffic Signaling and Better Energy Utilization

Agrawal, Manas 30 August 2013 (has links)
No description available.
54

Extraction of Driving Modes for Dynamic Speed Adaptation in Curves / Extrahering av körlägen för dynamisk hastighetsanpassning i kurvor

Kanter, Claudia January 2017 (has links)
Modern cars have a multitude of driver assistance functions that aim to support the driver in his/her everyday driving. One part of this is the Adaptive Cruise Control (ACC) that aims to keep a driver-specified speed. However, this set speed might be perceived as too high for some curves and as a result the driver will interrupt the system and take control again. To avoid this, a Curve Speed Adaptation (CSA) system aims to adapt the speed for an upcoming curve. Such a system should aim to mimic a driver and take into consideration how the driver would behave if he/she were to drive. This work aims to find a set of so-called Driving Modes that can describe how drivers with different driving styles drive through curves with different road properties by analysing recorded manual driving. A nested clustering approach is tested to divide curves into groups based on the driving style they were driven at and their road properties. The results show that this approach is able to capture different driving behaviours through curves. The road type and speed limit of a curve seem thereby to have the main influence on the driving behaviour. Clustering curves first by their driving style followed by the road properties yields thereby the more distinguishable Driving Modes. However, further improvements of the clustering methods are necessary to improve the obtained Driving Modes. The results of this thesis can form the basis for the development of a Curve Speed Adaptation system that adjusts for both the individual driver as well as particular road properties to improve the driver's comfort. / Moderna bilar har en mängd förarstödsystemer som syftar till att stödja föraren i sin dagligakörning. En av dem är Adaptive Cruise Control (ACC) som syftar till att hålla en hastighetspecificerad av föraren. Men denna hastighet kan uppfattas som för hög för vissa kurvoroch som resultat tar föraren kontrollen igen själv. För att undvika detta ska ett Curve SpeedAdaptation (CSA) system anpassa hastigheten för en kommande kurva. Ett sådant systembör sträva efter att efterlikna en förare och ta hänsyn till hur föraren skulle köra själv. Dethär examensarbetet syftar till att hitta så kallade körlägen som kan beskriva hur förare medolika körstilar kör genom kurvor med olika omständigheter genom att analysera manuellakörningar. En nestad klustringsmetod testas för att dela upp kurvor i grupper baserat påkörstilen som de kördes på och deras vägegenskaper. Resultaten visar att denna metod kanfånga olika körningsbeteenden genom kurvor. Vägtypen och hastighetsbegränsningen fören kurva verkar därmed ha huvudinverkan på körbeteendet. Att dela kurvorna först efterderas körstil följt av vägegenskaper ger bättre körlägena. Men ytterligare förbättringar avklustringsmetoderna är nödvändig för att förbättra de erhållna körningsmetoderna. Resul-taten av detta examensarbetet kan utgöra grunden för utvecklingen av ett kurvhastighetsanpassningssystem som anpassar både för den enskilda föraren och speciella vägegenskaperför att förbättra förarens komfort.
55

Simulation Studies of Impact of Heavy-Duty Vehicle Platoons on Road Traffic and Fuel Consumption

Johansson, Ingrid January 2018 (has links)
The demand for road freight transport continues to grow with the growing economy, resulting in increased fossil fuel consumption and emissions. At the same time, the fossil fuel use needs to decrease substantially to counteract the ongoing global warming. One way to reduce fuel consumption is to utilize emerging intelligent transport system (ITS) technologies and introduce heavy-duty vehicle (HDV) platooning, i.e. HDVs driving with small inter-vehicle gaps enabled by the use of sensors and controllers. It is of importance for transport authorities and industries to investigate the effects of introducing HDV platooning. Previous studies have investigated the potential benefits, but the effects in real traffic, both for the platoons and for the surrounding vehicles, have barely been explored. To further utilize ITS and optimize the platoons, information about the traffic situation ahead can be used to optimize the vehicle trajectories for the platoons. Paper I presents a dynamic programming-based optimal speed control including information of the traffic situation ahead. The optimal control is applied to HDV platoons in a deceleration case and the potential fuel consumption reduction is evaluated by a microscopic traffic simulation study with HDV platoons driving in real traffic conditions. The effects for the surrounding traffic are also analysed. Paper II and Paper III present a simulation platform to assess the effects of HDV platooning in real traffic conditions. Through simulation studies, the potential fuel consumption reduction by adopting HDV platooning on a real highway stretch is evaluated, and the effects for the other vehicles in the network are investigated. / Efterfrågan på godstransporter på väg fortsätter att öka i takt med den växande ekonomin, vilket resulterar i ökad förbrukning av fossila bränslen och ökade utsläpp. Samtidigt behöver användandet av fossila bränslen minska för att motverka den pågående globala uppvärmningen. Ett sätt för att minska bränsleförbrukningen är att utnyttja den teknik kring intelligenta transportsystem som är under utveckling och introducera lastbilskonvojer, det vill säga lastbilar som använder sensorer och regulatorer för att kunna köra med korta avstånd mellan sig. För transportföretag och -myndigheter är det viktigt att undersöka effekterna av att införa lastbilskonvojkörning. Tidigare studier har undersökt de möjliga fördelarna, men effekterna vid körning i trafik, både för konvojerna och för omgivande fordon, är outforskade. För att ytterligare utnyttja intelligenta transportsystem och optimera konvojerna kan information om trafiksituationen längre fram på vägen användas för att optimera konvojernas körning. Artikel I presenterar en optimal hastighetsregulator baserad på dynamisk programmering och som inkluderar information om trafiksituationen längre fram. Den optimala regulatorn appliceras på lastbilskonvojer under ett inbromsningsscenario och den potentiella minskningen i bränsleförbrukning utvärderas genom en mikroskopisk trafiksimuleringsstudie där lastbilskonvojerna kör i verkliga trafikförhållanden. Effekterna för omgivande fordon är också analyserade.Artikel II och artikel III presenterar en simuleringsplattform för att utvärdera effekterna av lastbilskonvojkörning i verkliga trafikförhållanden. Genom simuleringsstudier analyseras den potentiella bränsleförbrukningsminskningen då lastbilskonvojer körs på en verklig motorvägssträcka och effekterna för de övriga fordonen på vägen undersöks. / <p>QC 20180516</p>
56

Stability of a Vision Based Platooning System

Köling, Ann, Kjellberg, Kristina January 2021 (has links)
The current development of autonomous vehiclesallow for several new applications to form and evolve. One ofthese are platooning, where several vehicles drive closely togetherwith automatic car following. The method of getting informationabout the other vehicles in a platoon can vary. One of thesemethods is using visual information from a camera. Having acamera on-board an autonomous vehicle has further potential, forexample for recognition of objects in the vehicle’s surroundings.This bachelor thesis uses small RC vehicles to test an example ofa vision based platooning system. The system is then evaluatedusing a step response, from which the stability of the systemis analyzed. Additionally, a previously developed communicationbased platooning system was tested in the same way and it’sstability compared. The main conclusion of this thesis is that it isfeasible to use a camera, ArUco marker and an Optimal VelocityRelative Velocity model to achieve a vision based platoon on asmall set of RC vehicles. / Forskningsframsteg inom området autonoma fordon möjliggör utveckling av ett flertal nya tillämpningar. En av dessa är platooning, som innebär att flera fordon kör nära varandra med automatisk farthållning. Metoden för att erhålla information om de andra fordonen i platoonen kan variera. En av dessa metoder är att använda visuell information från en kamera. Att ha en kamera ombord på ett autonomt fordon har stor potential, exempelvis för detektering av objekt i fordonets omgivning. Det här kandidatexamensarbetet använder små radiostyrda bilar för att testa ett exempel av ett kamerabaserat platooning-system. Systemet är sedan utvärderat med hjälp av ett stegsvar, från vilket stabiliteten av systemet är analyserat. Dessutom testas ett tidigare utvecklat kommunikationsbaserat platooning-system, hittills bara testat i simulering, på samma uppsättning bilar. Den huvudsakliga slutsatsen av detta arbete är att det är möjligt att använda en kamera, ArUco markör och en Optimal Velocity Relative Velocity modell för att uppnå kamerabaserad platoon med en liten uppsättning radiostyrda bilar. / Kandidatexjobb i elektroteknik 2021, KTH, Stockholm
57

Formal Modelling of Cruise Control System Using Event-B and Rodin Platform

Predut, S., Ipate, F., Gheorghe, Marian, Campean, Felician 28 June 2018 (has links)
no / Formal modelling is essential for precisely defining, understanding and reasoning when designing complex systems, such as cyberphysical systems. In this paper we present a formal specification using Event-B and Rodin platform for a case study of a cruise control system for a hybrid propulsion vehicle and electric bicycle (e-Bike). Our work uses the EventB method, a formal approach for reliable systems specification and verification, being supported by the Rodin platform, based on theorem proving, allowing a stepwise specification process based on refinement. We also use, from the same platform, the ProB model checker for the verification of the B-Machine and iUML plug-in to visualize our model. This approach shows the benefits of using a formal modelling platform, in the context of cyberphysical systems, which provides multiple ways of analysing a system. / Romanian National Authority for Scientific Research, CNCS-UEFISCDI, project number PN-III-P4-ID-PCE-20160210.
58

Evolução de uma unidade de gerenciamento eletrônico de um motor VW 2.0L e desenvolvimento de controle de cruzeiro: Projeto Otto IV / Enhancement of an electronic management unit for a VW 2.0L engine and development of cruise control: Otto IV Project.

Bruno César Fernandes Pereira 25 August 2017 (has links)
Com o passar do tempo, nota-se um aumento gradativo da demanda por veículos mais econômicos e que disponham de itens capazes de aumentar o conforto e a segurança. Citase, como exemplo, o controle de cruzeiro (Cruise Control) que, atualmente presente em diversos veículos, é responsável por controlar a velocidade do veículo de maneira autônoma, sem a necessidade de intervenção do condutor no pedal de aceleração, resultando em um aumento de conforto ao reduzir o esforço para dirigir, além de prover efetividade para manter a velocidade do veículo em torno de um valor desejado. Neste contexto, o presente trabalho apresenta o desenvolvimento de um controlador de cruzeiro para operar em um veículo modelo Volkswagen Polo Sedan 2.0L 2004, o qual não possui este recurso em seu estado de fábrica. Para a implementação deste recurso, o trabalho faz uso de uma unidade de gerenciamento eletrônico (conhecida também por Electronic Control Unit - ECU) desenvolvida em 2013, no âmbito do projeto Otto II (PEREIRA, 2013), para controle do motor presente no respectivo veículo, viabilizando, desta forma, a validação do controle de cruzeiro por meio de testes utilizando o veículo em um dinamômetro inercial. Entretanto, previamente ao projeto do controlador de cruzeiro, o presente trabalho teve como foco o aperfeiçoamento do funcionamento desta ECU, visando a sua evolução no que diz respeito ao estado da arte de unidades de gerenciamento eletrônico de motores. Para isto, em sua primeira fase, o trabalho realizou diversas melhorias nas malhas de controle já existentes no firmware de 2013, tais como controle de marcha lenta, controle da borboleta eletrônica e controle de partida. Ao mesmo tempo, novos recursos foram implementados em firmware: controle de torque, controle da mistura ar/combustível em malha fechada (sonda lambda), segurança na comunicação entre blocos da ECU, identificação de marcha, suporte para diagnóstico via OBD-II, dentre outros. Além destas atividades envolvendo desenvolvimento de firmware, o trabalho, ainda em sua primeira fase, promoveu o desenvolvimento de uma nova ferramenta de software que, além de ser capaz de monitorar diversos parâmetros da ECU em tempo real, integra diversas funções, tais como função de computador de bordo alternativo, opção para controle do motor através da simulação do pedal de aceleração, opção para alteração da rotação de marcha lenta e função para automatização do ensaio de identificação do veículo (tarefa necessária para o projeto do controlador de cruzeiro). / Over time, there is a gradual increase of the demand for economical vehicles equipped with items capable of increasing the comfort and safety. As an example, the Cruise Control, which is already available in several vehicles, is responsible to control the vehicle speed in an autonomous manner, without the driver intervention on the throttle pedal. As a result, a greater comfort is achieved by reducing the effort to drive, besides providing effectiveness to keep the vehicle speed around a desired value. In this context, this project aims the development of a Cruise Control applied to a vehicle Volkswagen Polo Sedan 2.0L 2004, in which such resource is not available. To implement this resource, the project uses an electronic engine management unit (also known as Electronic Control Unit - ECU) developed in 2013 by the Otto II project (PEREIRA, 2013). This ECU is responsible to control the engine of the respective vehicle, which allows the Cruise Control validation through a set of tests performed with the vehicle on an inertial dynamometer. However, prior to the Cruise Control design, this project focused on the ECU operation enhancement, in order to achieve the state of the art in electronic engine management units. For this goal, the project, during its first phase, performed several improvements on the control algorithms already existing in the firmware developed in 2013, such as idle speed control, electronic throttle valve control and engine starting control. At the same time, new features were fully implemented in firmware: torque control, closed loop air/fuel ratio control (lambda control), safety for the communication among ECU blocks, gear identification, support to OBD-II diagnostic, among others. In addition to the firmware development activities, the project, still in its first phase, developed a new software tool capable of monitoring several ECU parameters in real time, besides providing many functions, such as alternative board computer, an option to control the engine by simulating the throttle pedal, an option to change the idle speed and a function to automate the system identification test (task required for the Cruise Control design).
59

Contrôle et optimisation des systèmes de transport intelligents dans le voisinage des intersections / Control and optimization for intelligent transportation systems in vicinity of intersections

Liu, Bing 09 September 2016 (has links)
Cette thèse est consacrée à étudier les applications potentielles de véhicules autonomes et communications V2X pour construire les systèmes de transport intelligents. Premièrement, le comportement de caravane dans un environnement de véhicule connecté est étudié. Un algorithme de commande de caravane est conçu pour obtenir l'espacement sécuritaire ainsi que la conformité de la vitesse et de l'accélération. Deuxièmement, à plus grande échelle, les caravanes autour d'une intersection sont considérées. Le débit pendant une période de signal de trafic peut être amélioré en tirant profit de la capacité redondante de la route. Dans diverses contraintes, les véhicules peuvent choisir d'accélérer et rejoindre la caravane précédente ou à décélérer de déroger à l'actuel. Troisièmement, une intersection sans signalisation en VANET est considérée. Dans des conditions de faible trafic, les véhicules peuvent réguler leur vitesse avant d'arriver à l'intersection en fonction du temps d'occupation de la zone de conflit (TOZC) stocké au niveau du gestionnaire, afin qu'ils puissent traverser l'intersection sans collision ni arrêt. Le délai peut être réduit en conséquence. Enfin, un algorithme de gestion d'intersection autonome universelle, qui peut fonctionner même avec le trafic lourd, est développé. Le véhicule cherche à sécuriser les fenêtres entrant dans le TOZC. Ensuite, sur la base des fenêtres trouvées et le mouvement du véhicule qui précède, les trajectoires des véhicules peuvent être planifiées en utilisant une méthode de programmation dynamique segmentée. Tous les algorithmes conçus sont testés et vérifiés avec succès par des simulations dans scénarios différents / This thesis is devoted to study the potential applications of autonomous vehicles and V2X communications to construct the intelligent transportation systems. Firstly, the behavior of platoon in connected vehicle environment is studied. A platoon control algorithm is designed to obtain safe spacing as well as accordance of velocity and acceleration for vehicles in the same lane. Secondly, in larger scale, the platoons around an intersection are considered. The throughput in a traffic signal period can be improved by taking advantage of the redundant road capacity. Within diverse constraints, vehicles can choose to accelerate to join in the preceding platoon or to decelerate to depart from the current one. Thirdly, an unsignalized intersection in VANET is considered. In light traffic conditions, vehicles can regulate their velocities before arriving at the intersection according to the conflict zone occupancy time (CZOT) stored at the manager, so that they could get through the intersection without collision or stop. The delay can be reduced accordingly. Finally, an universal autonomous intersection management algorithm, which can work even with heavy traffic, is developed. The vehicle searches for safe entering windows in the CZOT. Then based on the found windows and the motion of preceding vehicle, the trajectories of vehicles can be planned using a segmented dynamic programming method. All the designed algorithms are successfully tested and verified by simulations in various scenarios
60

Analyse de Performances de Régulateurs de Vitesse Adaptatifs Coopératifs / Cooperative Adaptive Cruise Control Performance Analysis

Sun, Qi 15 December 2016 (has links)
Cette thèse est consacrée à l'analyse de performance de Régulateurs de Vitesse Adaptatifs Coopératifs(CACC) pour un train de véhicules intelligents afin de réduire la congestion du trafic et améliorer la sécurité routière.Premièrement, la politique d'espacement, à Intervalles Constants de Temps (CTH) est introduite. Basé sur cette politique d'espacement, un nouveau système décentralisé de Deux-Véhicules-Devant CACC (TVACACC) est proposé, dans lequel l'accélération souhaitée de deux véhicules précédents est prise en compte. Ensuite, la stabilité de la chaîne du système proposé est analysée théoriquement. Il est démontré que grâce à l'aide de la communication multiple entre véhicules, une meilleure stabilité de la chaîne est obtenue par rapport au système conventionnel. Un train de véhicules dans le scénario Stop-and-Go est simulé avec une communication parfaite puis dégradée. Le système proposé donne un comportement stable de la chaîne, correspondant à l'analyse théorique.Deuxièmement, une technique de dégradation pour CACC est présentée comme stratégie alternative lorsque la communication sans fil est partiellement ou complètement perdue. La stratégie proposée, appelée DTVACACC, utilise le filtre de Kalman pour estimer l'accélération actuelle du véhicule précédent qui remplace l'accélération souhaitée. Il est démontré que la performance pour le DTVACACC, peut être maintenue à un niveau beaucoup plus élevé.Enfin, une approche d’Apprentissage par Renforcement (RL) pour système CACC est proposée. L' algorithme politique- gradient est introduit pour réaliser le contrôle longitudinal . Ensuite, la simulation a montré que cette nouvelle approche de RL est efficace pour CACC / This PhD thesis is dedicated to the performance analysis of Cooperative Adaptive Cruise Control (CACC) system for intelligent vehicle platoon with the main aims of alleviating traffic congestion and improving traffic safety. At first, the Constant Time Headway (CTH) spacing policy for vehicle platoon is introduced. Based on this spacing policy, a novel decentralized Two-Vehicle-Ahead CACC (TVACACC) system is proposed, in which the desired acceleration of two front vehicles is taken into account. Then the string stability of the proposed system is theoretically analyzed. It is shown that by using the multiple wireless communication among vehicles, a better string stability is obtained compared to the conventional system. Vehicle platoon in Stop-and-Go scenario is simulated with both normal and degraded communication.Secondly, a graceful degradation technique for CACC was presented, as an alternative fallback strategy when wireless communication is lost or badly degraded. The proposed strategy, which is referred to DTVACACC, uses Kalman filter to estimate the preceding vehicle’s current acceleration as a replacement of the desired acceleration. It is shown that the performance is maintained at a much higher level.Finally, a Reinforcement Learning (RL) approach of CACC system is proposed. The policy-gradient algorithm is introduced to achieve the longitudinal control. Then simulation has shown that this new RL approach results in efficient performance for CACC.

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