07 Fakultät Konstruktions-, Produktions- und Fahrzeugtechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/8
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Item Open Access Towards learning human-seat interactions for optimally controlled multibody models to generate realistic occupant motion(2023) Fahse, Niklas; Harant, Monika; Roller, Michael; Kempter, Fabian; Obentheuer, Marius; Linn, Joachim; Fehr, JörgItem Open Access On the validation of human body models with a driver-in-the-loop simulator(2018) Kempter, Fabian; Fehr, Jörg; Stutzig, Norman; Siebert, TobiasFor the development of modern integrated safety systems, standard simulation models of anthropometric test devices, often called crash test dummies, are inappropriate for Pre-Crash investigations due to missing activation possibilities, tuned characteristics for one specific accident scenario and high passive stiffness properties. To validate safety concepts getting active prior to the crash new tools like suitable virtual models of human occupants are required. Human Body Models (HBM) provide a higher biofidelity and can be equipped with active muscle elements enabling different muscle activation strategies. To improve the muscle activation strategy and the stiffness properties of active HBMs, validation processes on the basis of low-acceleration experiments are inevitable. In contrast to Post Mortem Human Surrogates only low-severity tests can be performed with real human subjects. This paper presents the workflow of a validation process based on an academic scale Driver-in-the-Loop (DiL) simulator in combination with a synchronized measurement chain consisting of an Optitrack stereo vision and an electromyography detection system.Item Open Access Finite element simulations of motorcyclist interaction with a novel passive safety concept for motorcycles(2021) Maier, Steffen; Doléac, Laurent; Hertneck, Holger; Stahlschmidt, Sebastian; Fehr, JörgItem Open Access Evaluation of a novel passive safety concept for motorcycles with combined multi-body and finite element simulations(2020) Maier, Steffen; Doléac, Laurent; Hertneck, Holger; Stahlschmidt, Sebastian; Fehr, JörgItem Open Access Accident simulations of a novel restraint safety concept for motorcyclists(2023) Maier, Steffen; Fehr, JörgItem Open Access Combining knowledge and information - graph-based description of driving scenarios to enable holistic vehicle safety(2023) Bechler, Florian; Fehr, Jörg; Neininger, Fabian; Knöß, Stefan; Grotz, BernhardCurrently, vehicle safety is based on knowledge from injury values, crash pulses, and driving kinematics which leads to intervention strategies separated into isolated domains of active and passive safety. In this contribution, it is shown how vehicle safety can be approached holistically, allowing for human-centered and scenario-based safety decision-making. For this purpose, information from interior and exterior vehicle sensors can be linked by a mathematical framework, combining the knowledge that is already available in the individual domains. A universal graph representation for driving scenarios is developed to master the complexity of driving scenarios and allow for an optimized and scenario-based intervention strategy to minimize occupant injury values. This novel approach allows for the inclusion of sub-models, expert knowledge, results from previous simulations, and annotated databases. The resulting graph can be expanded dynamically for other objects or occupants to reflect all available information to be considered in case of urgency. As input, interior and exterior vehicle sensor data is used. Further information about the driving situation is subsequently derived from this input and the interaction between those states is described by the graph dynamically. For example, occupant attentiveness is derived from measurable eye gaze and eyelid position. From this quantity, reaction time can be estimated in turn. Combined with exterior information, it is possible to decide on the intervention strategy like e.g. alerting the driver. Physical or data-based functional dependencies can be used to represent such interactions. The uncertainties of the inputs and from the surrogate models are included in the graph to ensure a reliable decision-making process. An example of the decision-making process, by modeling the states and actuators as partially observable Markov decision process (POMDP), shows how to optimize the airbag efficiency by influencing the head position prior to an impact. This approach can be extended by additional parameters like driving environment, occupant occupancy, and seating positions in further iterations to optimize the intervention strategy for occupants. The proposed framework integrates scenario-based driving dynamics and existing knowledge from so far separated safety systems with individual activation logic and trigger points to enable holistic vehicle safety intervention strategies for the first time. It lays the foundation to consider new safety hardware, sensor information, and safety functions through a modular, and holistic approach.Item Open Access Characterisation of an energy absorbing foam for motorcycle rider protection in LS-DYNA(2021) Maier, Steffen; Helbig, Martin; Hertneck, Holger; Fehr, JörgItem Open Access Positioning and simulation of human body models on a motorcycle with a novel restraint system(2022) Maier, Steffen; Kempter, Fabian; Kronwitter, Stefan; Fehr, JörgItem Open Access Muscular posture-adaption approach maintaining ligamentous stresses and strains(2021) Kempter, Fabian; Fehr, JörgItem Open Access Correlations of seat pressure distribution and perception of (dis)comfort in autonomous driving to parametrize digital human models(2024) Reinhard, René; Harant, Monika; Emmerich, Sebastian; Obentheuer, Marius; Fahse, Niklas; Fehr, Jörg; Kleer, Michael; Linn, JoachimWhile the driving position in a human-operated car restricts the driver’s body to a certain functional position, dictated by the requirements of observing the surrounding while having all the necessary controls in reach, for highly automated vehicles (SAE level 3 and up), these restrictions are lowered. This new freedom allows to perform non-driving-related tasks along with new seating positions including resting. The current driving simu lator study explores possible correlations between the subjective perception of (dis)comfort and the bodies’ mo tion, tracked by seat pressure mats and motion tracking sensors. The participants were confronted with evasive maneuvers with notable accelerations in lateral direction and yaw angle, while being seated in three different conditions in the driver’s seat inside the driving simulator RODOS®: (1) an alert condition, with their hands on the steering wheel, (2) a hands-free condition, where the seat was still in upright position, but the attention was not necessarily on the road, and (3), a reclined position, lying back in a reclined seat. This work identifies a correlation between the seat pressure distribution and the subjective (dis)comfort and shows its independence to the seating condition.