Validation of trajectory planning strategies for automated driving under cooperative, urban, and interurban scenarios.

149 p.En esta Tesis se estudia, diseña e implementa una arquitectura de control para vehículos automatizados de forma dual, que permite realizar pruebas en simulación y en vehículos reales con los mínimos cambios posibles. La arquitectura descansa sobre seis módulos: adquisición de información de sensores, percepción del entorno, comunicaciones e interacción con otros agentes, decisión de maniobras, control y actuación, además de la generación de mapas en el módulo de decisión, que utiliza puntos simples para la descripción de las estructuras de la ruta (rotondas, intersecciones, tramos rectos y cambios de carril)Tecnali

A Comparative Analysis of Deep Reinforcement Learning-enabled Freeway Decision-making for Automated Vehicles

Deep reinforcement learning (DRL) is becoming a prevalent and powerful methodology to address the artificial intelligent problems. Owing to its tremendous potentials in self-learning and self-improvement, DRL is broadly serviced in many research fields. This article conducted a comprehensive comparison of multiple DRL approaches on the freeway decision-making problem for autonomous vehicles. These techniques include the common deep Q learning (DQL), double DQL (DDQL), dueling DQL, and prioritized replay DQL. First, the reinforcement learning (RL) framework is introduced. As an extension, the implementations of the above mentioned DRL methods are established mathematically. Then, the freeway driving scenario for the automated vehicles is constructed, wherein the decision-making problem is transferred as a control optimization problem. Finally, a series of simulation experiments are achieved to evaluate the control performance of these DRL-enabled decision-making strategies. A comparative analysis is realized to connect the autonomous driving results with the learning characteristics of these DRL techniques.Comment: 11 pages, 10 figure

A multiple-goal reinforcement learning method for complex vehicle overtaking maneuvers

In this paper, we present a learning method to solve the vehicle overtaking problem, which demands a multitude of abilities from the agent to tackle multiple criteria. To handle this problem, we propose to adopt a multiple-goal reinforcement learning (MGRL) framework as the basis of our solution. By considering seven different goals, either Q-learning (QL) or double-action QL is employed to determine action decisions based on whether the other vehicles interact with the agent for that particular goal. Furthermore, a fusion function is proposed according to the importance of each goal before arriving to an overall but consistent action decision. This offers a powerful approach for dealing with demanding situations such as overtaking, particularly when a number of other vehicles are within the proximity of the agent and are traveling at different and varying speeds. A large number of overtaking cases have been simulated to demonstrate its effectiveness. From the results, it can be concluded that the proposed method is capable of the following: 1) making correct action decisions for overtaking; 2) avoiding collisions with other vehicles; 3) reaching the target at reasonable time; 4) keeping almost steady speed; and 5) maintaining almost steady heading angle. In addition, it should also be noted that the proposed method performs lane keeping well when not overtaking and lane changing effectively when overtaking is in progress. © 2006 IEEE.published_or_final_versio

Ein Beitrag zur taktischen Verhaltensplanung für Fahrstreifenwechsel bei automatisierten Fahrzeugen

Automated driving within one lane is a fascinating experience. Yet, it is even more interesting to go a step ahead: Making automated lane changes without human driver interaction. This thesis presents a concept and implementation demonstrated in "Jack", the Audi A7 piloted driving concept vehicle. Given that automated driving is in the media every other day already, why is it still such a big issue to do tactical behavior planning for automated vehicles? It is one of the core areas where it is surprisingly obvious why humans are currently so much smarter than machines: Tactical driving behavior planning is a social task that requires cooperation, intention recognition, and complex situation assessment. Without complex cognitive capabilities in today's automated vehicles, it is core of this thesis to find simple algorithms that pretend intelligence in behavior planning. In fact, such behavior planning in automated driving is a constant trade-off between utility and risk: The vehicle has to balance value dimensions such as safety, legality, mobility, and additional aspects like creating user and third party satisfaction. This thesis provides a framework to boil down such abstract dimensions into a working implementation. Several of the foundations for this thesis were developed as part of the Stadtpilot project at TU Braunschweig. While there has been plenty of research on concepts being tested in perfect, simulated worlds only, the approaches in this thesis have been implemented and evaluated in real world traffic with uncertain and imperfect sensor data. The implementation has been tested, tweaked, and used in "Jack" for more than 50,000 km of automated driving in everyday traffic.Automatisiertes Fahren innerhalb eines Fahrstreifens ist eine faszinierende Erfahrung. Noch spannender ist es jedoch noch einen Schritt weiter zu gehen: Auch Fahrstreifenwechsel automatisiert auszuführen, ohne Interaktion mit einem Menschen als Fahrer. In dieser Dissertation wird hierfür ein Konzept und dessen Umsetzung in „Jack“ präsentiert, dem Audi A7 piloted driving concept Fahrzeug. Automatisiertes Fahren ist aktuell in den Medien in aller Munde. Warum ist es dennoch eine große Herausforderung taktische Verhaltensplanung für automatisierte Fahrzeuge wirklich umzusetzen? Es ist einer der Kernbereiche, in denen offensichtlich wird, warum Menschen aktuell Maschinen im Straßenverkehr noch weitaus überlegen sind: Taktische Verhaltensplanung ist eine soziale Aufgabe, welche Kooperation, das Erkennen von Absichten und der Bewertung komplexer Situationen bedarf. Mangels wirklicher kognitiver Fähigkeiten in den heutigen automatisierten Fahrzeugen ist es Kern dieser Dissertation Algorithmen zu finden, welche zumindest den Eindruck intelligenter Verhaltensplanung erzeugen. Eine solche Verhaltensplanung ist ein permanentes Abwägen von Nutzen und Risiken. Das Fahrzeug muss permanent Entscheidungen im Spannungsfeld zwischen Sicherheit, Legalität, Mobilität und weiten Aspekten wie Nutzerzufriedenheit und Zufriedenheit Dritter treffen. In dieser Dissertation wird ein Konzept entwickelt, um solche abstrakten Entscheidungsdimensionen in ein implementierbares Konzept herunterzubrechen. Viele Grundlagen dafür wurden im Rahmen des Stadtpilot Projekts der TU Braunschweig erarbeitet. In vorausgehenden Arbeiten wurden bereits viele Ansätze entwickelt und auf Basis von perfekten, simulierten Daten evaluiert. Der in dieser Arbeit präsentierte Ansatz ist in der Lage mit unsicherheits- und fehlerbehafteten Messdaten umzugehen. Der Ansatz aus dieser Dissertation wurde in dem automatisiert fahrenden Fahrzeug „Jack“ implementiert und bereits über 50.000 km im normalen Straßenverkehr genutzt und getestet

Safety of autonomous vehicles: A survey on Model-based vs. AI-based approaches

The growing advancements in Autonomous Vehicles (AVs) have emphasized the critical need to prioritize the absolute safety of AV maneuvers, especially in dynamic and unpredictable environments or situations. This objective becomes even more challenging due to the uniqueness of every traffic situation/condition. To cope with all these very constrained and complex configurations, AVs must have appropriate control architectures with reliable and real-time Risk Assessment and Management Strategies (RAMS). These targeted RAMS must lead to reduce drastically the navigation risks. However, the lack of safety guarantees proves, which is one of the key challenges to be addressed, limit drastically the ambition to introduce more broadly AVs on our roads and restrict the use of AVs to very limited use cases. Therefore, the focus and the ambition of this paper is to survey research on autonomous vehicles while focusing on the important topic of safety guarantee of AVs. For this purpose, it is proposed to review research on relevant methods and concepts defining an overall control architecture for AVs, with an emphasis on the safety assessment and decision-making systems composing these architectures. Moreover, it is intended through this reviewing process to highlight researches that use either model-based methods or AI-based approaches. This is performed while emphasizing the strengths and weaknesses of each methodology and investigating the research that proposes a comprehensive multi-modal design that combines model-based and AI approaches. This paper ends with discussions on the methods used to guarantee the safety of AVs namely: safety verification techniques and the standardization/generalization of safety frameworks

Learning Behavior Models for Interpreting and Predicting Traffic Situations

In this thesis, we present Bayesian state estimation and machine learning methods for predicting traffic situations. The cognitive ability to assess situations and behaviors of traffic participants, and to anticipate possible developments is an essential requirement for several applications in the traffic domain, especially for self-driving cars. We present a method for learning behavior models from unlabeled traffic observations and develop improved learning methods for decision trees

Modeling Drivers’ Strategy When Overtaking Cyclists in the Presence of Oncoming Traffic

Overtaking a cyclist on a two-lane rural road with oncoming traffic is a challenging task for any driver. Failing this task can lead to severe injuries or even death, because of the potentially high impact speed in a possible collision. To avoid a rear-end collision with the cyclist, drivers need to make a timely and accurate decision about whether to steer and overtake the cyclist, or brake and let the oncoming traffic pass first. If this decision is delayed, for instance because the driver is distracted, neither braking nor steering may eventually keep the driver from crashing—at that point, rear-ending a cyclist may be the safest alternative for the driver. Active safety systems such as forward collision warning that help drivers being alert and avoiding collisions may be enhanced with driver models to reduce activations perceived as false positive. In this study, we developed a driver model based on logistic regression using data from a test-track experiment. The model can predict the probability and confidence of drivers braking and steering while approaching a cyclist during an overtaking, and therefore this model may improve collision warning systems. In both an in-sample and out-of-sample evaluation, the model identified drivers’ intent to overtake with high accuracy (0.99 and 0.90, respectively). The model can be integrated into a warning system that leverages the deviance of the actual driver behavior from the behavior predicted by the model to allow timely warnings without compromising driver acceptance