Road traffic safety has been a subject of worldwide concern. Dedicated short range communications (DSRC) is widely regarded as a promising enabling technology for collaborative safety applications (CSA), which can provide robust communication and affordable performance to build large scale CSA system. The main focus of this thesis is to develop solutions for DSRC QoS control in order to provide robust QoS support for CSA. The first design objective is to ensure robust and reliable message delivery services for safety applications from the DSRC networks. As the spectrum resources allocated to DSRC network are expected to be shared by both safety and non-safety applications, the second design objective is to make QoS control schemes bandwidth-efficient in order to leave as much as possible bandwidth for non-safety applications. The first part of the thesis investigates QoS control in infrastructure based DSRC networks, where roadside access points (AP) are available to control QoS control at road intersections. After analyse DSRC network capabilities on QoS provisioning without congestion control, we propose a two-phases adaptive QoS control method for DSRC vehicle networks. In the first phase an offline simulation based approach is used to and out the best possible system configurations (e.g. message rate and transmit power) with given numbers of vehicles and QoS requirements. It is noted that with different utility functions the values of optimal parameters proposed by the two phases centralized QoS control scheme will be different. The conclusions obtained with the proposed scheme are dependent on the chosen utility functions. But the proposed two phases centralized QoS control scheme is general and is applicable to different utility functions. In the second phase, these configurations are used online by roadside AP adaptively according to dynamic traffic loads. The second part of the thesis is focused on distributed QoS control for DSRC networks. A framework of collaborative QoS control is proposed, following which we utilize the local channel busy time as the indicator of network congestion and adaptively adjust safety message rate by a modified additive increase and multiplicative decrease (AIMD) method in a distributed way. Numerical results demonstrate the effectiveness of the proposed QoS control schemes.

[pt] O presente trabalho apresenta um conceito para um sistema de evasão de colisões, simulado usando modelos 3D de três veículos diferentes implementados em MATLAB. Dois destes veículos foram parametrizados com dados genéricos, caracterizando automóveis de médio e grande porte. Em seguida, utilizados para realização de simulações iniciais e demonstração de conceitos. O terceiro conjunto de dados foi construído com informações do Apollo N, um veículo super esportivo. Estes diferentes conjuntos de dados foram utilizados para avaliar a capacidade do controlador de trabalhar com veículos de diferentes portes e dinâmicas de direção. A abordagem para acionar o sistema baseia-se no cálculo do tempo para a colisão (TTC; timeto- collision). O conceito foi adotado para detectar situações onde o motorista não é capaz de evitar um acidente. Depois de ser acionado, o sistema deve decidir qual manobra é a mais apropriada, dadas as condições de aderência da pista e o risco associado. O primeiro objetivo deste trabalho é desenvolver um sistema autônomo de frenagem que deve ser capaz de avaliar o risco de uma possível colisão e decidir se o condutor é capaz de evitá-la. Uma vez que o motorista não tenha tempo suficiente para reagir, o sistema deve acionar os freios automaticamente a fim de evitar um possível acidente. Além disso, o veículo possui um sistema anti-travamento (ABS), desenvolvido usando controle Fuzzy. O desempenho do controlador ABS foi avaliado em simulações usando os conjuntos de dados e testado em um veículo em escala. Em casos mais críticos, quando há baixa aderência, o veículo não é capaz de frear em uma distância razoável. Levando-se em consideração tal situação, um controle autônomo de esterçamento também foi desenvolvido, visando a possibilidade de uma manobra alternativa de evasão. Este segundo sistema foi avaliado em simulações utilizando veículos com características subesterçantes e sobreesterçantes. Os resultados mostraram que o controle de esterçamento foi capaz de realizar manobras evasivas produzindo valores razoáveis de acelerações laterais, em veículos com diferentes dinâmicas de direção. / [en] This work presents a concept for a collision avoidance system simulated using 3D-models of three different vehicles implemented in MATLAB. Two of the vehicle data sets were built with generic information, used to characterize mid-size and full-size vehicles. These standard vehicles were used in initial simulations and for demonstration of some concepts. The third data set was built with information from the Apollo N, a super sportive car. These different data sets were used to evaluate the controller s capacity to work with a range of vehicles, with different sizes and driving characteristics. The approach for triggering the system is based on the time-to-colision (TTC) estimation. This concept was adopted to recognize when the driver is not able to avoid an accident. After being triggered, the system must decide which maneuver is the most appropriate for the given friction and risk conditions. The first goal of this work is to develop an autonomous braking system which evaluates the risk of a possible collision and decides if the driver is able to avoid it. Once the driver has not enough time to react, the system must trigger the brakes automatically in order to avoid the accident. The vehicle is equipped with an embedded Anti-lock Brake System (ABS) developed using Fuzzy control. The ABS controller s performance was evaluated in simulations using the data sets and tested in a scaled vehicle. In more critical cases, when there is low friction, the vehicle is not able to brake in a reasonable distance. Considering this situation, an autonomous steering control was implemented in order to make an alternative avoidance maneuver. This second system was evaluated in simulations using vehicles with understeering and oversteering characteristics. The results pointed out that the autonomous steering control was able to perform avoidance maneuvers in a reasonable range of lateral accelerations, in vehicles with different driving tendencies. / [de] Die vorliegende Arbeit prasentiert ein Konzept fur ein Kollisionsvermeidungssystem. Dieses wird anhand von drei verschiedenen 3DFahrzeugmodellen mit Hilfe von MATLAB simuliert. Zwei der FahrzeugDatensatze basieren auf generischen Informationen, die jeweils ein Automobil der Mittelklasse und der Oberklasse reprasentieren. Diese Standardfahrzeuge wurden fur anfangliche Simulationen und zur Demonstration einiger Konzepte verwendet. Das dritte Fahrzeugmodell wurde mit Hilfe der Daten des Sportwagens Apollo N aufgebaut. Durch die Verwendung der verschiedenen Datensatze soll die Funktionsfahigkeit der Regelung auch bei verschiedenen Fahrzeugtypen mit unterschiedlichen Dimensionen und Fahreigenschaften uberpruft werden.Die Grundlage zum Auslosen des Systems ist die Abschatzung der Zeit bis zur Kollision (TTC; time-to-collision). Dieses Konzept wurde aufgegriffen, um zu entscheiden, wann der Fahrer nicht mehr in der Lage ist einen Unfall zu vermeiden. Nachdem das System ausgelost wird muss dieses anhand der Traktionsverhaltnisse und Gefahrensituation entscheiden, welches Manover am besten geeignet ist. Das erste Teilziel ist die Entwicklung eines autonomen Bremssystems, welches eine bevorstehende Kollision erkennen muss und entscheidet ob der Fahrer die Kollision eigenstandig vermeiden kann. Sobald der Fahrer nicht mehr genug Zeit hat selbst zu reagieren, muss das System die Bremsen automatisch betatigen um den Unfall zu vermeiden. Hierzu ist das Fahrzeug mit einem Antiblockiersystem (ABS) ausgestattet. Dieses wurde mit Hilfe eines Fuzzy-Kontrollers realisiert. Die Funktionstuchtigkeit der ABS-Regelung wurde mit Simulationen und anhand eines realen, skalierten Fahrzeugmodells getestet. In kritischen Situationen, kann es aufgrund der Traktionsverhaltnisse vorkommen, dass das Fahrzeug nicht mehr in der Lage ist innerhalb einer ausreichenden Strecke zum Stehen zu kommen. Um fur solche Situationen ein alternatives Ausweichmanöver anwenden zu konnen, wurde ein automatischer Lenkeingriff implementiert. Dieses System wurde anhand von Simulationen an Fahrzeugmodellen mit Ubersteuernden und Untersteuernden Eigenschaften uberprüft. Die Ergebnisse zeigten, dass die automatische Lenkeingriff-Regelung in der Lage war auch bei Fahrzeugen mit unterschiedlichen Fahreigenschaften Ausweichmanöver unter Einhaltung angemessener Querbeschleunigungen durchzufuhren.

Indiana University-Purdue University Indianapolis (IUPUI) / Pedestrian Automatic Emergency Braking (PAEB) system for avoiding/mitigating pedestrian crashes have been equipped on some passenger vehicles. At present, there are many e orts for the development of common standard for the performance evaluation of PAEB. The Transportation Active Safety Institute (TASI) at Indiana University-Purdue University-Indianapolis has been studying the problems and ad- dressing the concerns related to the establishment of such a standard with support from Toyota Collaborative Safety Research Center (CSRC). One of the important components in the PAEB evaluation is the development of standard testing facili- ties at night, in which 70% pedestrian crash social costs occurs [1]. The test facility should include representative low-illuminance environment to enable the examination of sensing and control functions of di erent PAEB systems. This thesis work focuses on modeling low-illuminance driving environment and describes an approach to recon- struct the lighting conditions. The goal of this research is to characterize and model light sources at a potential collision case at low-illuminance environment and deter- mine possible recreation of such environment for PAEB evaluation. This research is conducted in ve steps. The rst step is to identify lighting components that ap- pear frequently on a low-illuminance environment that a ect the performance of the PAEB. The identi ed lighting components include ambient light, same side/opposite side light poles, opposite side car headlight. Next step is to collect all potential pedes- trian collision cases at night with GPS coordinate information from TASI 110 CAR naturalistic driving study video database. Thirdly, since ambient lighting is relatively random and lack of a certain pattern, ambient light intensity for each potential col- lision case is de ned and processed as the average value of a region of interest on all video frames in this case. Fourth step is to classify interested light sources from the selected videos. The temporal pro le method, which compressing region of interest in video data (x,y,t) to image data (x,y), is introduced to scan certain prede ned region on the video. Due to the fact that light sources (except ambient light) impose distinct light patterns on the road, image patterns corresponding to speci c light sources can be recognized and classi ed. All light sources obtained are stamped with GPS coordinates and time information which are provided in corresponding data les along with the video. Lastly, by grouping all light source information of each repre- sentative street category, representative light description of each street category can be generated. Such light description can be used for lighting construction of PAEB test facility.

Indiana University-Purdue University Indianapolis (IUPUI) / The Pedestrian Automatic Emergency Braking System (PAEB) can utilize on-board sensors to detect pedestrians and take safety related actions. However, PAEB system only benefits the individual vehicle and the pedestrians detected by its PAEB. Additionally, due to the range limitations of PAEB sensors and speed limitations of sensory data processing, PAEB system often cannot detect or do not have sufficient time to respond to a potential crash with pedestrians. For further improving pedestrian safety, we proposed the idea for integrating the complimentary capabilities of V2V and PAEB (V2V-PAEB), which allows the vehicles to share the information of pedestrians detected by PAEB system in the V2V network. So a V2V-PAEB enabled vehicle uses not only its on-board sensors of the PAEB system, but also the received V2V messages from other vehicles to detect potential collisions with pedestrians and make better safety related decisions. In this thesis, we discussed the architecture and the information processing stages of the V2V-PAEB system. In addition, a comprehensive Matlab/Simulink based simulation model of the V2V-PAEB system is also developed in PreScan simulation environment. The simulation result shows that this simulation model works properly and the V2V-PAEB system can improve pedestrian safety significantly.