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Coupling of RT Systems

Full Title: Fault-Tolerant Coupling of Real-Time Systems: A Case Study

Language: EN


This paper demonstrates the application of a model-based coupling approach to cope with non negligible coupling imperfections and faults of interconnected real-time systems. Performance degradation of the coupled overall system is prevented via model-based prediction schemes, which compensate for effects caused by e.g. deadline violations of the coupled real-time systems or data losses and transmission time delays due to the communication network. As an example, the real-time co-simulation setup of a modular driving simulator demonstrates the practical applicability and effectiveness of the proposed coupling approach.



FIR-Filter Design for RT Systems

Full Title: Recursive FIR-Filter Design for Fault-Tolerant Real-Time Co-Simulation

Language: EN


The coupling of real-time and non-real-time systems is directly related to different types of faults which require adequate handling. These faults, such as communication time-delays, data-loss or noisy measurements, originate from the incorporation of real hardware (real-time system) and lead to significant challenges in the coupling process. Without compensating their destabilizing effects the simulation results are corrupted. Ignoring those effects can even result in unstable closed-loop systems in the worst case, which may in turn result in hardware damage. This work proposes a recursive FIRfilter design approach which compensates such fault effects. The effectiveness of the proposed coupling filters is demonstrated by a representative example.




Model based coupling to control a magnetic levitation system

Full Title: Control of a magnetic levitation system with communication imperfections: A model-based coupling approach

Language: EN


This work presents a control strategy to control a magnetic levitation system under the influence of coupling imperfections (disturbances). To overcome problems arising whenever the interconnections between plant and controller have a non-negligible influence on the control-loop behavior a so-called model-based coupling approach is used. The main idea of this coupling approach is to use prediction schemes based on recursively identified plant and controller models which compensate for performance degradation due to coupling imperfections. Coupling failures such as time-delays, data-losses and noise drastically influence the controlloop performance. Especially when systems in form of real hardware (real-time systems) are present such disturbances have to be handled adequately. To demonstrate the effectiveness of the model-based coupling approach, a control-loop of a magnetic levitation system is analyzed in simulation as well as in real world laboratory setup (HiL simulation). Furthermore a first insight into the stability analysis of closed-loop systems including the model-based coupling technique is performed for a simplified configuration.


Modellbasierte Echtzeit-Co-Simulation

Full Title: Modellbasierte Echtzeit-Co-Simulation: Überblick und praktische Anwendungsbeispiele

Language: DE


Diese Arbeit behandelt die sogenannte Echtzeit-Co-Simulationsproblematik. Im Speziellen wird die Einbindung von Hardwarekomponenten in einen Softwareverbund durch kommunikationsbedingte Latenzzeiten und Messrauschen erschwert. Zur Behandlung dieser Störungen wird ein modellbasierter Kopplungsansatz vorgestellt. Mittels Prädiktion von Koppelgrößen können die Auswirkungen von Störeinflüssen deutlich reduziert werden. Die Effektivität dieses Kopplungsansatzes wird an einem Labormodell demonstriert. Darüber hinaus werden einige typische industrielle Anwendungsszenarien skizziert.