Tommi Karhela

OPEN ONTOLOGY-BASED INTEGRATION PLATFORM FOR MODELING AND SIMULATION IN ENGINEERING

The benefits of the use of modeling and simulation in engineering are acknowledged widely. It has proven its advantages e.g., in virtual prototyping i.e., simulation aided design and testing as well as in training and R&D. It is recognized to be a tool for modern decision making. However, there are still reasons that slow down the wider utilization of modeling and simulation in companies. Modeling and simulation tools are separate and are not an integrated part of the other engineering information management in the company networks. They do not integrate well enough into the used CAD, PLM/PDM and control systems. The co-use of the simulation tools themselves is poor and the whole modeling process is considered often to be too laborious. In this article we introduce an integration solution for modeling and simulation based on the semantic data modeling approach. Semantic data modeling and ontology mapping techniques have been used in database system integration, but the novelty of this work is in utilizing these techniques in the domain of modeling and simulation. The benefits and drawbacks of the chosen approach are discussed. Furthermore, we describe real industrial project cases where this new approach has been applied.

Developing a mobile, service-based augmented reality tool for modern maintenance work

In the VTT PLAMOS (Plant Model Services for Mobile Process Maintenance Engineer) project new tools were developed for modern maintenance work carried out in industrial plants by either the plant personnel or personnel of an industrial service provider. To formulate the requirements for new tools the work of a maintenance man was studied with a particular method, the Core-Task Analysis which has its roots in study and development of work in complex settings. The aim was to develop and create concepts for novel tools that would support the development of good work practices in a situation where the work is concurrently undergoing several transformations. Hence, the new tools should have potential to enable and affect new ways of working.

A toolset for model checking of PLC software

Model checking is a powerful formal verification method that can also be used to evaluate PLC software. A lot of manual work and some expertise are still needed. Proposed methods for automating the process rely on standardised specification languages, but PLC software is often vendor-specific, and the source code for function blocks may not even be available. We propose a toolset for model checking of function block based software. After manually modelling the elementary function block library, the model of any block diagram can be specified with easy-to-use graphical tools. The counterexamples output by the model checker can also be visualised using a “living” function block diagram. Our toolset is based on integrating the popular model checker NuSMV with the open source modelling platform Simantics.

A hybrid approach for the initialization of tracking simulation systems

In the online and tracking simulation context, precise model initialization is highly important to ensure the quality of predictions made based on simulation. This paper presents a hybrid approach for the initialization of tracking simulation systems that combines different techniques and utilizes the persistent communication between model and process in order to initialize the simulation model. In the proposed approach, the model initialization is performed throughout different stages. A model is first fed with initial conditions that are close to the physical plants state. Then, the model is run to the same state as the physical system using a process control system. Possible mass or energy errors in the state of the simulation model are corrected before the actual tracking process is started. This paper first introduces previously studied initialization techniques for online simulation systems. Then the proposed hybrid initialization method is elaborated. Finally, its implementation is demonstrated using a simple but representative process system.

Co-simulation of a dynamic process simulator and an event-based control system: Case district heating system

A smart electric grid incorporating local generation and storage is an area of active research in the industrial automation community. Very little attention has been given to similar possibilities in hot water grids that are used extensively for district heating in several countries, especially in Central and Northern Europe. In this paper, possibilities for heat trade in such a grid are investigated through simulation, considering the thermo-hydraulic properties of such a grid. For the distributed automation of several independent producer-consumers, an event based IEC 61499 solution is presented. The paper proposes a co-simulation environment for a dynamic process simulator and an event based control system, which is applied to the district heating case.

Requirement verification in simulation-based automation testing

The emergence of the Industrial Internet results in an increasing number of complicated temporal interdependencies between automation systems and the processes to be controlled. There is a need for verification methods that scale better than formal verification methods and which are more exact than testing. Simulation-based runtime verification is proposed as such a method, and an application of Metric temporal logic is presented as a contribution. The practical scalability of the proposed approach is validated against a production process designed by an industrial partner, resulting in the discovery of requirement violations.

Capturing Deviations From Design Intent in Building Simulation Models for Risk Assessment

Simulation-based methods are emerging to address the challenges of complex systems risk assessment, and this paper identifies two problems related to the use of such methods. First, the methods cannot identify new hazards if the simulation model builders are expected to foresee the hazards and incorporate the abnormal behavior related to the hazard into the simulation model. Therefore, this paper uses the concept of deviation from design intent to systematically capture abnormal conditions that may lead to component failures, hazards, or both. Second, simulation-based risk assessment methods should explicitly consider what expertise is required from the experts that build and use the simulation models—the transfer of the methods to real engineering practice will be severely hindered if they must be performed by persons that are expert in domain safety as well as advanced computer simulation-based methods. This paper addresses both problems in the context of the functional failure identification and propagation (FFIP) method. One industrially established risk assessment method, hazard and operability study (HAZOP), is harnessed to systematically obtain the deviations from design intent in the application under study. An information system presents a user interface that is understandable to HAZOP professionals, so that their inputs are transparently entered to a data model that captures the deviations. From the data model, instructions for configuring FFIP simulation models are printed in a form that is understandable for FFIP experts. The method is demonstrated for discovering a hazard resulting from system-wide fault propagation in a boiling water reactor case.

An Unstructured Semantic Mesh Definition Suitable for Finite Element Method

Numerical methods, such as finite element method (FEM), are widely used for computations on meshes in variety of simulation related software applications. As these methods become more popular in engineering, also information management requirements for these models are growing. Neutral data formats and standards are needed in order to achieve vendor independence and transformation between different tools. Semantic data modelling is one modern and potential technique that can be used for this purpose. In this paper, we propose our Semantic mesh data structure that can be used in development of semantic software applications, which use meshes. The proposed structure is universal and can be used for representing meshes used in wide number of popular FEM applications such as e.g. Abaqus FEA, I-DEAS or MSC Adams. Our Semantic mesh proposal can be also used for mesh based simulations with other methods than FEM, such as e.g. finite volume method used in computational fluid dynamics (CFD). Also it can be used outside focus of numerical simulations, e.g. for projects related to scientific data visualization and computer graphics. We provide a description of our Semantic mesh, together with an example of a very simple 2D mesh, illustrating our proposal. The implementation is using the semantic database in Simantics software platform.

Automated Process Design Using Web-Service based Parameterised Constructors

This paper introduces a web-service based approach in conceptual process design, parameterised constructors, which are able to construct process and initial data for control system configuration. Constructors use unit process or larger sub-process templates readily available in a plant model library. The templates consist of upper level process structures, control descriptions and detailed process structures. Thus, the preliminary process design can be defined in a more general level and as the design process proceeds, more accurate models (e.g. PI and automation diagrams, simulation models) are composed and used. Definitions of a common data model are also discussed.

Internet-based equipment and model gallery

Abstract The paper presents an Internet-based integrated design environment, which aims to enhance the efficiency and quality of process and control design in process industry. The main idea is to improve the utilisation and distribution of simulation models and vendor-based equipment information to the designers and other customers in a ready available form. The information can be directly utilised by equipment selection tools and various process simulators both steady state and dynamic. The system is based on the use of Internet as a distribution channel and on the presentation form of information, which makes it compatible to different end user software.