Integrating AADL and FMI to Extend Virtual Integration Capability

Virtual Integration Capability is paramount to perform early validation of Cyber Physical Systems. The objective is to guide the systems engineer so as to ensure that the system under design meets multiple criteria through high-fidelity simulation. In this paper, we present an integration scheme that leverages the FMI (Functional Mock-Up interface) standard and the AADL architecture description language. Their combination allows for validation of systems combining embedded platform captured by the AADL, and FMI components that represent physical elements, either mechanical parts, or the environment. We present one approach, and demonstrator case studies

Scaling of Distributed Multi-Simulations on Multi-Core Clusters

International audienceDACCOSIM is a multi-simulation environment for continuous time systems, relying on FMI standard, making easy the design of a multi-simulation graph, and specially developed for multi-core PC clusters, in order to achieve speedup and size up. However, the distribution of the simulation graph remains complex and is still the responsibility of the simulation developer. This paper introduces DACCOSIM parallel and distributed architecture, and our strategies to achieve efficient multi-simulation graph distribution on multi-core clusters. Some performance experiments on two clusters, running up to 81 simulation components (FMU) and using up to 16 multi-core computing nodes, are shown. Performances measured on our faster cluster exhibit a good scalability, but some limitations of current DACCOSIM implementation are discussed

Future Perspectives of Co-Simulation in the Smart Grid Domain

The recent attention towards research and development in cyber-physical energy systems has introduced the necessity of emerging multi-domain co-simulation tools. Different educational, research and industrial efforts have been set to tackle the co-simulation topic from several perspectives. The majority of previous works has addressed the standardization of models and interfaces for data exchange, automation of simulation, as well as improving performance and accuracy of co-simulation setups. Furthermore, the domains of interest so far have involved communication, control, markets and the environment in addition to physical energy systems. However, the current characteristics and state of co-simulation testbeds need to be re-evaluated for future research demands. These demands vary from new domains of interest, such as human and social behavior models, to new applications of co-simulation, such as holistic prognosis and system planning. This paper aims to formulate these research demands that can then be used as a road map and guideline for future development of co-simulation in cyber-physical energy systems

Cyber-physical energy systems modeling, test specification, and co-simulation based testing

The gradual deployment of intelligent and coordinated devices in the electrical power system needs careful investigation of the interactions between the various domains involved. Especially due to the coupling between ICT and power systems a holistic approach for testing and validating is required. Taking existing (quasi-) standardised smart grid system and test specification methods as a starting point, we are developing a holistic testing and validation approach that allows a very flexible way of assessing the system level aspects by various types of experiments (including virtual, real, and mixed lab settings). This paper describes the formal holistic test case specification method and applies it to a particular co-simulation experimental setup. The various building blocks of such a simulation (i.e., FMI, mosaik, domain-specific simulation federates) are covered in more detail. The presented method addresses most modeling and specification challenges in cyber-physical energy systems and is extensible for future additions such as uncertainty quantification

Investigating Concurrency in the Co-Simulation Orchestration Engine for INTO-CPS

There is a tendency to expect, that taking advantage of multicore systems by using concurrency improves the performance of an application. To investigate if this is true, a case study was performed where different concurrency principles were applied to an existing application called the Co-Simulation Orchestration Engine (COE), which did not utilize concurrency. This was explored in the context of Co-Simulation using the Functional Mock-up Interface, as applications executing Co-Simulations should be performant to enable the use of increasingly complex models.Co-Simulation can be useful in the development of Cyber-Physical Systems, as it can be used to simulate coupled technical systems or models and thereby examine the behavior of the systems.The investigation was carried out by refactoring the COE to make it suitable for implementing concurrency by limiting the spawning of threads and synchronization between threads, along with maximizing the workload for each thread. Three different concurrency features were used in three different implementations: Parallel collections, futures, and actors, which were evaluated based on selected quality attributes. These implementations were tested against the non-refactored sequential COE and each other by performing different simulations using different models.The case study showed, that concurrency can be used to increase the performance of the COE in some cases. Based on the analysis carried out in this thesis project, a set of guidelines were created to generalize the process of applying concurrency to an existing application

FMI for Co-Simulation of Embedded Control Software

Increased complexity of cyber-physical systems within the maritime industry demands closer cooperation be-tween engineering disciplines. The functional mockup interface (FMI) is an initiative aiding cross-discipline in-teraction by providing, a widely accepted, standard for model exchange and co-simulation. The standard is sup-ported by a number of modelling tools. However, to im-plement it on an existing platform requires adaptation. This paper investigates how to adapt the software of an embedded control system to comply with the FMI for co-simulation standard. In particular, we suggest a way of advancing the clock of a real time operating system (RTOS), by overwriting the idle thread and waiting for a signal to start execution until return to idle. This ap-proach ensures a deterministic and temporal execution of the simulation across multiple nodes. As proof of concept, a co-simulation is conducted, showing that the control system of an SCR (selective catalyst reduction) emission reduction system can be packed in a functional mockup unit (FMU) and co-simulated with a physical model, built in Ptolemy II. Results show that FMI can be used for co-simulation of an embedded SCR control soft-ware and for control software development