Frédéric Etienne Kracht

Generalized Method for Real-Time Object-Oriented Modeling and Simulation of Systems Applied to a Vehicle Wheel Suspension Mechanism

It is becoming increasingly important to simulate the dynamic behavior of complex systems in order to make real-time predictions about the performance of the system. The modeling technique has to be computationally efficient and accurate. In this work, a novel object-oriented modeling method is presented, which is characterized by high modularity and computational efficiency. This method is particularly useful for performing real-time simulations and is characterized by a high degree of configurability, scalability and is found to be faster than the established multibody simulation software like ADAMS and DYMOLA. The developed method can be used to predict the dynamic behavior of open-loop as well as closed-loop systems in real time. The method is demonstrated by using it to model a vehicle suspension system for predicting the dynamic response of the mechanism.

Observing the Durability Effects of a Formula Student Electric Car using Acceleration and Strain Signals

This paper presents the durability analysis of suspension system from an electric Formula Student race car using strain and acceleration signals. To have outstanding performance in a competition, the Formula Student car was required to have light weight but safe design. To evaluate the suspension design of the vehicle, strain and acceleration signals were collected under a vehicle double lane change event according to the ISO 3888 testing procedure. Strain signals were measured on the wheel carrier and lower control arm of the Formula Student car. Meanwhile, tri-axis accelerations were measured on the wheel and chassis of the vehicle during the testing. In addition, the wheel displacement relative to vehicle chassis was measured using laser sensors. The fatigue life of the lower arm and wheel carrier were predicted using the measured strain signals. Due to limited instrument, a quarter car model was simulated using wheel displacement signals to obtain spring force signals for fatigue estimation. The simulation model was validated using the measured chassis acceleration signal. Ride and whole-body vibration of the vehicle were also assessed using the measured acceleration signals. Through this analysis, the durability effects of the Formula Student car suspension system were identified. The Formula Student car suspension design could be improved through understanding the vibration behaviour.

Passing Control Between Driver and Highly Automated Driving Functions

In this paper challenges to face in “taking over control from highly automated driving mode” are derived from human driving patterns and a technological analysis of the vehicle state. On the same basis, an automated driving model (driver model) is generated and used for studies in a driving simulator. Finally, strategies, which support the driver in taking over control from highly automated driving are designed in three different levels, implemented and tested in a driving simulator.

Advantages and potentials of a blown film cooling system with a complete housing of the tube formation zone

In a prior work, a novel cooling approach for the blown film application was developed, called Multi-Jet. In contrast to a conventional cooling ring, this alternative cooling system guides the air vertically on the film surface, using several slit nozzles over the whole tube formation zone. In addition, the bubble expansion zone is surrounded by a housing. In this context, the cooling jets penetrate the boundary sublayer on the film surface that is developed by the fast flowing cooling air. The advantage of the housing can been seen in the disablement of the interaction of the cooling jet and the static ambient air. Besides the exhausting of the monomer loaded air, the housing allows to realize a heat recovery of the warmed cooling air. In this paper, an experimental and numerical investigation of the novel cooling system is shown. Here a comparison is done for several different process conditions with and without the use of the housing for the tube formation zone. By the means of a CFD-simulation, the co...

An experimental comparison between a novel and a conventional cooling system for the blown film process

The blown film extrusion is a significant manufacturing process of plastic films. Compared to other extrusion processes, the productivity is limited by the cooling of the extrudate. A conventional cooling system for the blown film application provides the cooling air tangentially, homogeneous over the whole circumference of the bubble, using a single or dual lip cooling ring. In prior works, major effects could be identified that are responsible for a bad heat transfer. Besides the formation of a boundary sublayer on the film surface due to the fast flowing cooling air, there is the interaction between the cooling jet and the ambient air. In order to intensify the cooling of a tubular film, a new cooling approach was developed, called Multi-Jet. This system guides the air vertically on the film surface, using several slit nozzles over the whole tube formation zone. Hence, the jets penetrate the sublayer. To avoid the interaction with the ambient air, the bubble expansion zone is surrounded by a housing. B...

Einfluss der Radaufhängungskomponenten auf die Energieeffizienz des Gesamtfahrzeugs

Wahrend der letzten Jahre gestattete die Entwicklung innovativer Systeme in der Fahrzeugtechnik insbesondere im Bereich des Antriebsstranges eine signifikante Steigerung der Energieeffizienz des Gesamtfahrzeugs. Motiviert wird dieser Trend unter anderem darauf, dass die fossilen Brennstoffe endlich sind und eine Ressourcenknappheit in der mittleren Zukunft zu erwarten ist. Getrieben wird diese Entwicklung durch den stetigen Wachstum der Weltbevolkerung (ein Plus von ca. 80 Millionen Menschen pro Jahr [1]) und mit diesem auch die steigende Anzahl der potenziellen Autofahrer (Prognose fur 2030: 1475,5 Millionen Fahrzeuge weltweit [2]).

Development of a chassis model including elastic behavior for real-time applications

For the prediction of the dynamics of vehicles, various mathematical models have been used successfully for many years. The complexity of these models ranges from very sophisticated to rather straightforward approaches. The right to exist for simple models often results from the need for short computation times due to many iterations associated with optimization tasks or even from real-time applications. If the models are to be used as part of driving dynamics control systems these computations have to be performed on ECUs affordable for series applications.