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BACKGROUND: The increasing electrification poses new challenges with respect to thermal comfort in vehicle passenger cabins. While conventional air heating with electric heaters is technically possible, it causes significant reductions in the electric driving range. OBJECTIVE: Two contradicting objectives are to be achieved: Fast heat up to provide thermal comfort and high energy efficiency to maximize the driving range under all conditions. METHODS: This apparent area of conflict can be eased by the usage of low temperature radiation reducing the energy intensive heat up of the cabin air. In order to provide high energy efficiency, the emitted radiation should mostly be directed towards relevant body regions of the passengers, resulting in the necessity to redesign the passenger cabin. RESULTS: A novel approach to redesign and optimize the dashboard and a resulting radiation heating system are presented. In order to reduce computational effort of such an optimization, the complex three-dimensional geometry is sliced into simplified two-dimensional regions which are considered individually. The resulting heating system has been manufactured and integrated into a class A vehicle. Objective thermal comfort measurements as well as subjective comfort ratings have been conducted to validate the simulative approach and the resulting energy savings of approximately 30 %. CONCLUSIONS: The developed approach to achieve a fast time to comfort as well as an increased energy efficiency shows promising results as the heating system based on it cuts performs well considering objective and subjective measurements.
Asunto(s)
Frío , Calefacción , Humanos , TemperaturaRESUMEN
Objective: In order to introduce automated vehicles on public roads, it is necessary to ensure that these vehicles are safe to operate in traffic. One challenge is to prove that all physically possible variations of situations can be handled safely within the operational design domain of the vehicle. A promising approach to handling the set of possible situations is to identify a manageable number of logical scenarios, which provide an abstraction for object properties and behavior within the situations. These can then be transferred into concrete scenarios defining all parameters necessary to reproduce the situation in different test environments. Methods: This article proposes a framework for defining safety-relevant scenarios based on the potential collision between the subject vehicle and a challenging object, which forces the subject vehicle to depart from its planned course of action to avoid a collision. This allows defining only safety-relevant scenarios, which can directly be related to accident classification. The first criterion for defining a scenario is the area of the subject vehicle with which the object would collide. As a second criterion, 8 different positions around the subject vehicle are considered. To account for other relevant objects in the scenario, factors that influence the challenge for the subject vehicle can be added to the scenario. These are grouped as action constraints, dynamic occlusions, and causal chains. Results: By applying the proposed systematics, a catalog of base scenarios for a vehicle traveling on controlled-access highways has been generated, which can directly be linked to parameters in accident classification. The catalog serves as a basis for scenario classification within the PEGASUS project. Conclusions: Defining a limited number of safety-relevant scenarios helps to realize a systematic safety assurance process for automated vehicles. Scenarios are defined based on the point of the potential collision of a challenging object with the subject vehicle and its initial position. This approach allows defining scenarios for different environments and different driving states of the subject vehicle using the same mechanisms. A next step is the generation of logical scenarios for other driving states of the subject vehicle and for other traffic environments.
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Automatización , Conducción de Automóvil , Seguridad , HumanosRESUMEN
OBJECTIVE: State-of-the-art collision avoidance and collision mitigation systems predict the behavior of pedestrians based on trivial models that assume a constant acceleration or velocity. New sources of sensor information-for example, smart devices such as smartphones, tablets, smartwatches, etc.-can support enhanced pedestrian behavior models. The objective of this article is the development and implementation of a V2Xpedestrian collision avoidance system that uses new information sources. METHODS: A literature review of existing state-of-the-art pedestrian collision avoidance systems, pedestrian behavior models in advanced driver assistance systems (ADAS), and traffic simulations is conducted together with an analysis of existing studies on typical pedestrian patterns in traffic. Based on this analysis, possible parameters for predicting pedestrian behavior were investigated. The results led to new requirements from which a concept was developed and implemented. RESULTS: The analysis of typical pedestrian behavior patterns in traffic situations showed the complexity of predicting pedestrian behavior. Requirements for an improved behavior prediction were derived. A concept for a V2X collision avoidance system, based on a cost function that predicts pedestrian near future presence, and its implementation is presented. The concept presented considers several challenges such as information privacy, inaccuracies of the localization, and inaccuracies of the prediction. CONCLUSION: A concept for an enhanced V2X pedestrian collision avoidance system was developed and introduced. The concept uses new information sources such as smart devices to improve the prediction of the pedestrian's presence in the near future and considers challenges that come along with the usage of these information sources.