Browsing by Author "Till, Markus"

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Open Access
Digital development process for the drive system of a balanced two-wheel scooter
(2021) Holder, Kevin; Schumacher, Sven; Friedrich, Matthias; Till, Markus; Stetter, Ralf; Fichter, Walter; Rudolph, Stephan
Graph-based design languages have received increasing attention in the research community, because they offer a promising approach to address several major issues in engineering, e.g., the frequent manual data transfer between computer-aided design (CAD) and computer-aided engineering (CAE) systems. Currently, these issues prevent the realization of machine executable digital design processes of complex systems such as vehicles. Promising scenarios for urban transportation include an interconnection of mass transportation systems such as buses and subways with individual vehicles for the so-called “last mile” transport. For several reasons, these vehicles should be as small and light as possible. A considerable reduction in weight and size can be achieved, if such vehicles are tailored to the individual size, weight and proportion of the individual user. However, tailoring vehicles for the individual characteristics of each user go beyond a simple building set and require a continuous digital design process. Consequently, the topic of this paper is a digital design process of a self-balanced scooter, which can be used as an individual last-mile means of transport. This process is based on graph-based design languages, because in these languages, a digital system model is generated, which contains all relevant information about a design and can be fed into any simulation tool which is needed to evaluate the impact of a possible design variation on the resulting product performance. As this process can be automated by digital compilers, it is possible to perform systematic design variations for an almost infinite amount of parameters and topological variants. Consequently, these kinds of graph-based languages are a powerful means to generate viable design alternatives and thus permit fast evaluations. The paper demonstrates the design process, focusing on the drive system of the respective balanced two-wheel scooter and highlights the advantages (data integration and possibility for machine execution).
Open Access
Digital function modeling in graph-based design languages
(2022) Elwert, Michael; Ramsaier, Manuel; Eisenbart, Boris; Stetter, Ralf; Till, Markus; Rudolph, Stephan
The main focus of this paper is the integration of an integrated function modeling (IFM) framework in an engineering framework based on graph-based design languages (GBDLs). Over the last decade, GBDLs have received increasing attention as they offer a promising approach for addressing several important challenges in engineering, such as the frequent and time-consuming transfer of data between different computer aided engineering (CAE) tools. This absorbs significant amounts of manual labor in engineering design projects. GBDLs create digital system models at a meta level, encompassing all relevant information concerning a certain product design and feeding this into the relevant simulation tools needed for evaluating the impact of possible design variations on the performance of the resulting products/parts. It is possible to automate this process using digital compilers. Because of this, it is also possible to realize systematic design variations for a very large number of parameters and topological variants. Therefore, these kinds of graph-based languages are a powerful means for creating a large number of viable design alternatives and for permitting fast evaluation processes against the given specifications. While, thus far, such analyses tend to be based on a more or less fully defined system, this paper proposes an expansion of the applicability of GBDLs into the domain of product functions to cohesively link conceptual with embodiment design stages. This will also help with early systematic, automated generation and the validation of design alternatives through relevant simulation tools during embodiment design. Further, it will permit the automated exploration of function paths and enable extended analysis possibilities, such as the detection of functional bottlenecks, while enhancing the traceability of the design over the development process. For these extended analysis possibilities, a function analysis tool was developed that adopts core ideas of the failure mode and effects analysis (FMEA). In this, the functional distinction between function carriers and function-related processes allows the goal-directed assessment of component reliabilities and the detectability and importance of processes in a technical system. In the paper, the graph-based modeling of functions and the function analysis tools are demonstrated on the example of a multicopter.
Open Access
Simulation-based prediction of the cold start behavior of gerotor pumps for precise design of electric oil pumps
(2024) Schumacher, Sven; Stetter, Ralf; Till, Markus; Laviolette, Nicolas; Algret, Benoît; Rudolph, Stephan
The development of electric gerotor pumps is a complex multiphysical optimization problem. To develop optimal systems, accurate simulation models are required to increase digital reliability. An important challenge is the accurate prediction of the pump behavior for extreme temperatures in automotive applications from -40°C to 110 °C, where the viscosity of the fluid changes significantly. Therefore, simulation-based methods (numerical methods for calculating viscous friction) were developed and validated by measurements, including climatic chamber tests. The results show a strong correlation between simulated and measured performance characteristics, especially in terms of volumetric flow rate ( <5%), pump torque and efficiency ( <7%) at different temperature and viscosity conditions over a wide speed range (1000-5000 rpm) and different system pressures (0.5-5 bar). A novel method for simulating the cold start behavior of pumps (journal bearing approach for outer gear in pump housing) was introduced and validated by measurements. The methods presented significantly reduce the need for physical testing and accelerate the development process, as the pump behavior at each operating point can be accurately predicted before a hardware prototype is built. This improves the understanding of gerotor pump characteristics and provides insights to further improve the model-based development of electric oil pumps for the automotive industry.