An execution sequence approach of interacting subsystem is presented for non-iterative co-simulation frameworks. Local behaviour of coupling signals and subsystems are used to describe a general optimization problem o...
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ISBN:
(纸本)9789897583810
An execution sequence approach of interacting subsystem is presented for non-iterative co-simulation frameworks. Local behaviour of coupling signals and subsystems are used to describe a general optimization problem of co-simulation. Therefore the linking matrix is weighted by analysis of the coupling signals within fuzzy integrated expert knowledge. The weighted linking matrix is transferred to a directed co-simulation graph, which can be interpreted as an appropriate travelling sales man problem. The solution of this co-simulation graph provides an optimized trigger sequence of the subsystems.
Modular simulation requires efficient coupling of the involved subsystems. Subsystems are independently solved and synchronized at coupling time instants. By the commonly used non-iterativecoupling approach the extra...
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ISBN:
(纸本)9780769550732
Modular simulation requires efficient coupling of the involved subsystems. Subsystems are independently solved and synchronized at coupling time instants. By the commonly used non-iterativecoupling approach the extrapolation of some coupling quantities is necessary because of bidirectional dependencies between subsystems. Thus, a coupling step-size dependent coupling error is introduced. Required sampling of the coupling signals may lead to aliasing effects and unintentional discontinuities at coupling time instants occur. A recently developed coupling error compensation approach seems to be able to solve the typical problems concerning non-iterative co-simulation. However, for adequate usage of the available functionalities proper settings of the proposed coupling scheme are mandatory. In this work, the basic nearly energy-preserving coupling approach is explained and significant extensions are proposed. Especially, the resulting enhanced coupling performance enables smoothing of the coupling signals without degradation of the overall system behavior. The resulting effects as well as the specific adjustments are discussed, which leads to supporting parameterization guidelines.
This paper explores the improvement of non-iterative co-simulation master. A simple hybrid system is depicted and analyzed. Based on this analysis guidelines for calculating the calling sequence are introduced. Guidel...
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ISBN:
(纸本)9781450350921
This paper explores the improvement of non-iterative co-simulation master. A simple hybrid system is depicted and analyzed. Based on this analysis guidelines for calculating the calling sequence are introduced. Guidelines allow the implementation of a new constraint programming algorithm. This algorithm allows better calling sequence selection based solely on information about connecting the co-simulation network. The algorithm is confirmed by the example of co-simulation of a hybrid electric vehicle. In this example, the constraint programming algorithm found a subjectively good calling sequence without any involvement of the model developer.
co-simulation has become a trending topic of simulation techniques in the recent years with an emerging need for complex system development. However it can show inconsistent results compared with mono-simulation due t...
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co-simulation has become a trending topic of simulation techniques in the recent years with an emerging need for complex system development. However it can show inconsistent results compared with mono-simulation due to the drawbacks of modular integration. Many research works have been done on various types of co-simulation. The scope of this thesis is to have a fundamental understanding including stability and error analysis for parallel co-simulation with force/displace- ment coupling. In the thesis we have shown that the co-simulation error is dom- inated by the coupling error rather than error by numerical method. In addition the causality and interface selection have an important effect on the robustness of co-simulation results, which can further implies to higher degree extrapolation and multi-subsystems. The study based on a basic dual mass-spring-damper research model can indicate how a complex system can be partitioned in a robust manner. Besides, a state-of-the-art co-simulation technique called nearly energy-preserving- coupling-element (NEPCE) has been referred and evaluated. The techniques is based on the concept of preserving energy in the power bond and use the resid- ual energy as the error indicator. From the analytical and numerical results of the thesis it is shown that the concept has a limited usage in our research model. A new "causality-based extrapolation" method has been proposed based on the rough knowledge of the system and interface dynamics. It is more accurate than mono- lower-degree extrapolation and faster than mono-higher-degree extrapolation. In certain cases, the improvement can be almost as good as mono-higher-degree ex- trapolation. This discovery is extendable to multi-subsystems as well. Lastly the different designs of interface and extrapolation methods have been tested on a co-simulation case study of high fidelity electric power assisted steering (EPAS) model and chassis model.
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