Modelica Newsletter 2009-3 (December 2009)
Table of Contents
- Letter from the Board
- Modelica Association News
- Successful Modelica Conference in Como
- Modelica Standard Library 3.1 Released
- New Library for Magnetic circuits (in MSL3.1)
- New Library for State Diagrams
- New Library for Linear Control Systems
- Educational News
- Library News
- Tool News
Dear Modelica Interested,
this is now already the third newsletter in this year, and still has plenty of information:
- The most important event of the Modelica Association in the last quarter was the 7th Modelica Conference, see below. Despite the economic crisis, the conference took place successfully with 30 % more articles as at the last Modelica conference and with exciting keynotes from Dassault Systèmes, Daimler and Siemens.
- A new version of the Modelica Standard Library was released containing two new sub-libraries (Fluid, Magnetics), see below. Additionally, two new, free libraries ( Modelica_StateGraph2, Modelica_LinearSystems2) are available for download. It is planned to include these libraries in a future version of the Modelica Standard Library.
- As you may have noticed, the Modelica Web was improved. Especially, the entry page was newly designed, a compact overview of 30 important free and commercial libraries is now available, and the web layout was slightly improved. If an important library is missing in the overview, please send an email to Martin Otter.
- In order to spread Modelica to people that do not yet have heared about it, a press release has been sent out to several hundred technical journals and online services via the press agency PR Newswire.
- Modelon and the department of vehicle engineering at TU München organized a seminar to teach model-based design of electrical vehicles with Modelica, see below. Contact Modelon, if you are interested in a similar seminar, especially to teach students in this hot topic.
- BAUSCH-GALL GmbH offers marketing and distribution of commercial Modelica libraries for all Modelica tools. They extend their library portfolio with two new libraries (Visualization, BG_RT), see below.
- Modelica tool vendors have further developed their tools (see below SimulationX Modelica Edition, Dymola 7.3).
In case you have some interesting news for the Modelica community, feel free to write a short article in plain html (and eventually png or jpg images) and send it to the newsletter editor (Michael Tiller) for possible inclusion in the next newsletter. The deadline for articles for the next newsletter is March 1, 2010.
Best wishes from the Board of the Modelica Association:
Martin Otter, Chairman (DLR Germany)
Peter Fritzson, Vice-Chairman (Linköping University, Sweden)
Michael Tiller, Secretary (Emmeskay, U.S.A.)
Hilding Elmqvist, Treasurer (Dassault Systèmes/Dynasim, Sweden)
Modelica Association News
The 7th International Modelica Conference, organized by the Modelica Association and Politecnico di Milano, successfully took place in Como, Italy, on September 20-22, 2009. The Conference was attended by 219 people from industry and academia. The five tutorials on Sunday afternoon were attended by over a hundred people. 83 regular papers and 22 poster papers were presented in the technical sessions, and a record number of nine Modelica-enable tools were presented in the tool presentation sessions. Three keynote talks were delivered by industry representatives from Dassault Systèmes, Daimler, and Siemens, outlining the status of three ITEA2 European projects which are focused on the use of Modelica for systems engineering in various domains.
All the conference material, including the papers, is available online as usual on the Modelica website. The full volume of the proceedings is also published by Linköping University Electronic Press, and is referenced through DOI: 10.3384/ecp0943.
There have been 6 applications for the Library award. These free, new libraries can be downloaded from the online proceedings. The Programme Chair and the Programme Board selected the following applications for this award:
- 1. Prize (500 €):
The FluidDissipation library from XRG Simulation GmbH is an outstanding free library providing heat transfer and pressure loss functions for fluid models. It is planned to include this library in a future version of the Modelica Standard Library.
- 2. Prize (250 €):
The WheelsAndTires library from Markus Andres, Vorarlberg University of Applied Sciences (master thesis at ETH Zürich, Prof. Cellier) provides an implementation of a seven-level tire model dedicated for real-time applications.
This article is provided by Francesco Casella (Politecnico di Milano) .
The new version 3.1 of the Modelica Standard Library was released on August 14, 2009. This open source library can be downloaded from www.modelica.org/libraries. It is already available in Dymola 7.3 and will be shipped with other Modelica tools soon. In the figure to the right, some new features are visualized. An overview of all sub-libraries is now available from the new "library overview" web page. Summary of the most important new features:
- The new version is backward compatible to versions 3.0 and 3.0.1. It contains about 920 models and 620 functions.
- The new sub-library Modelica.Fluid has been added to model 1-dim. thermo-fluid flow in networks of vessels, pipes, fluid machines, valves and fittings. All media from the Modelica.Media library can be used. The library is based on the stream-concept from Modelica 3.1 for reliable and efficient simulation of bi-directional thermo-fluid flow. (see also Newsletter 2009-1).
- The new sub-library Modelica.Magnetic.FluxTubes has been added to model electro-magnetic actuators based on the magnetic flux tubes concepts (see details below).
- Several new components have been added to the Modelica.Electrical.Analog library, such as: detailed operational amplifier, Z-Diode, thyristor, opener and closer with arc.
- The components in the Modelica.Electrical.Analog and Modelica.Electrical.MultiPhase sub-libraries that have losses (resistor, transistor etc.) have now an optional heat port to connect to a thermal network defined by the Modelica.Thermal.HeatTransfer library. When enabled, the generated heat can be, e.g., distributed from the electrical components to the environment.
- The Modelica.Mechanics.MultiBody library has been extended with components to model ideal rolling wheels and wheel pairs.
- The new top level package ModelicaServices has been introduced. Inspired by services in Java, this library shall contain models and functions to be used in the Modelica Standard Library that requires a tool specific implementation. In this first version, the 3-dim. animation defined with Modelica.Mechanics.MultiBody.Visualizers.Advanced.Shape was moved to ModelicaServices. Tool vendors and interested users can now provide their own implementation of the animation in a much easier way. It is planned to extend ModelicaServices in the next releases with more tool-specific features.
This article is provided by Martin Otter (DLR-RM) .
The method of magnetic flux tubes is used since many decades for rough design of the magnetic circuit of transformers, electric motors and generators or electromagnetic actuators. It consists of an approximation of a magnetic field by simple geometric shapes for which a magnetic reluctance or permeance can be calculated. Flux densities and actuator forces can be obtained from the resulting lumped magnetic network models.
The FluxTubes library, developed by Thomas Bödrich, is included in the Modelica Standard Library 3.1 as Modelica.Magnetic.FluxTubes. It is an improved version of the Magnetic library which has been available for download at the Modelica web site for more than two years. It contains network elements for many flux tube shapes as well as material characteristics of selected soft and hard magnetic materials. A converter between electric and magnetic energy (coil) and converters between magnetic and translatory mechanical energy (various flux tube elements) allow for dynamic simulation of magnetic network models at system level. At present, components and examples for modelling of translatory electromagnetic and electrodynamic actuators are provided. If needed, these components can be adapted to network modelling of rotational electrical machines.
This article is provided by Thomas Boedrich (Technische Universität Dresden) .
Library Modelica_StateGraph2 is a new free Modelica package providing components to model discrete event, reactive and hybrid systems in a convenient way with deterministic hierarchical state diagrams. It was developed within the EUROSYSLIB project. The library can be downloaded from www.modelica.org/libraries. It is already shipped with Dymola 7.3. In the figure to the right, a typical example is shown. A more detailed description is given in an article of the Modelica'2009 conference. It is planned to include this library as Modelica.StateGraph, version 2.0, in a future version of the Modelica Standard Library replacing the current Modelica.StateGraph, version 1.0, library.
The library has the following basic components: Step, Transition, Parallel. The Parallel component is both used as "composite step" (so only one branch), as well as "parallel step" (so several execution branches). The branches can be synchronized (as in "Sequential Function Charts") or can run unsynchronized to each other (as in "Statecharts"). In both cases a Parallel component can be suspended and resumed. A sub-library contains input/output blocks to define actions that depend on the active step, such as MultiSwitch, OnDelay, TriggeredAdd blocks.
The library supports safe state diagrams: (a) Wrong graphs give a translation error, e.g. two initial steps. (b) Several transitions can fire at an event instant. Still, there is an upper bound on the execution time since every loop must have one delayed transition. (c) The state diagrams are deterministic since every variable must be defined exactly by one equation.
This article is provided by Martin Otter (DLR-RM) and Martin Malmheden (Dassault Systèmes/Dynasim) .
Library Modelica_LinearSystems2 is a new free Modelica package providing different representations of linear, time invariant differential and difference equation systems. Operators are overloaded to work conveniently with these system descriptions in an interactive environment, e.g., to multiply transfer functions or to operate on complex numbers. About 180 Modelica functions are provided to operate on these data structures, e.g., to compute eigen values, zeros, step responses, to design pole-placement and LQG controllers, to plot step responses, frequency responses, eigen values, to convert between different description forms, or to generate a linear system description by linearization of a Modelica model.
Furthermore, sublibrary Controller contains about 20 input/output blocks of linear systems that are based on the different representation forms, e.g., PID, StateSpace, Filter blocks. A unique feature of these blocks is that it is very convenient to quickly switch between a continuous and a discrete block representation. Also, templates are provided to quickly built-up standard controller structures using replaceable models.
A more detailed description of this library is given in an article of the Modelica'2009 conference. It can be downloaded from www.modelica.org/libraries. It is planned to include the library in a future version of the Modelica Standard Library. The library uses the open source LAPACK software for the core numerical operations (clapack 3.1.1) and was developed within the EUROSYSLIB project.
This article is provided by Marcus Bauer (DLR-RM) .
The last week in October, a seminar about Dymola, Modelica and the Vehicle Dynamics Library was given at the Technische Universität München (TUM), department for Vehicle Engineering (FTM). FTM has a strong focus on vehicle handling and electric mobility and are developing among other things the Experimental Handling Vehicle and EF1. The EF1 is an electric vehicle with four in-wheel motors that opens up for new ways of vehicle dynamics control to improve active safety and driving agility.
The initiative to the seminar was taken in order to further strengthen FTM's position in especially model-based design of electrical vehicles, based on Modelica. The seminar was organised by Robert Pietsch and Peter Burda from FTM, and given in cooperation with Modelon, represented by Johannes Gerl and Johan Andreasson. The seminar will be given as a university course on regular basis, open for students at TUM.
This article is provided by Johan Andreasson (Modelon AB) .
In the last Modelica newsletter, BAUSCH-GALL announced the (world-wide) distribution of the commercial Modelica Libraries Belts, FlexibleBodies and HumanComfort. Today, two more commercial libraries are announced which will be soon distributed:
- Visualization Library (from DLR-RM)
This library provides model integrated, offline and online, animation for Modelica models, especially in the mechanical, fluid and electrical area. Components are attached to a model with a Frame connector of the Modelica.Mechanics.MultiBody library. The library contains visualizers for elementary shapes (boxes, spheres etc.), CAD files (3ds, dxf, obj, stl), flexible shapes (based on CAD files), flexible surfaces with textures, flow visualizers, text, light, head-up displays, and particle effects (rain, snow, fog, etc.). The library supports multi-camera scenes, a full-screen mode, several monitors, replays and stereo/wireframe modes, and is based on the OpenSceneGraph software. Animation replays can be exported as Windows Media, Flash, MPEG4, and Lossless HUFF video. The library is available for Dymola 7. It is planned to make it available for SimulationX soon.
- BG_RT (from BAUSCH-GALL GmbH)
This library provides components to access data acquisition (DAQ) cards directly from a Modelica simulator. It was designed to allow the usage of the Dymola Realtime option with DAQ cards without any further programming effort. Currently we support the card NI-USB6009 from National Instruments. Functions for reading and writing analog and digital data are provided. BG_RT allows easy and low cost HiL-simulation. Only a standard Windows PC with Dymola, option Realtime and a DAQ card are needed. The library is delivered with complete source code, including the code of all C-routines. Therefore it can be used as programming template for other DAQ cards. The library is available for Dymola 7. It is planned to make it available for SimulationX soon.
A small catalog of Modelica Libraries is available at www.bausch-gall.de/prod.htm. If you need more information, or if you are interested in a demo version, or if you are looking for a company to market your commercial Modelica library, please contact email@example.com.
This article is provided by Ingrid Bausch-Gall (BAUSCH-GALL GmbH) .
CAE specialist ITI GmbH launches the new Modelica Edition of its multi-domain software platform SimulationX.
SimulationX has long proven its capability to fully support Modelica language. No matter if the model is part of the Modelica standard library or whether it is purely based on the Modelica language definition, any model can be easily executed. Integrated Modelica Smart Editor tools such as the SimulationX TypeDesigner guide through every step of the modeling process and thus simplify the development of even most complex models considerably.
New in upcoming SimulationX 3.3 (All Editions)
The creation of real-time capable Modelica models is significantly improved in the upcoming SimulationX release:
- Model reductions are often necessary in order to achieve real time behavior. Using the SimulationX Performance Analyzer in combination with the new fix step solvers critical parts can be localized and optimized purposefully.
- Addition of the support of National Instruments tools to the SimulationX Code Export. Modelica models can now be seamlessly integrated with LabVIEW and NI's new software environment NI Veristand for configuring real-time testing applications.
- New Modelica editor with syntax highlighting and autocompletion
- Improved Documentation View for quick access to reference manuals
- Fully editable connection lines with automatic generation of junctions
For further information, please contact firstname.lastname@example.org or visit www.simulationx.com.
LabVIEW, NI and NI Veristand are trademarks of National Instruments.
This article is provided by Manuela Noetzel (ITI GmbH) .
Dymola 7.3 was released in September 2009. It contains many enhancements and extensions, for example:
New editor for Modelica text
- Syntax highlighting and indentation while you type.
- Word completion and bracket matching.
- Improved support for displaying model structure and toggling of annotations.
Mathematical rendering of expressions
- Mathematical rendering of Modelica expressions makes model equations and command output much easier to comprehend.
Documentation and user interface
- Built-in browser for model documentation.
- Direct-manipulation HTML editor facilitates model documentation.
- The graphical editor and the plot window support convenient zooming and panning using the mouse.
- Editor to annotate the command window for report generation.
Support for Modelica 3.1 language and standard library
- Operator overloading, already used for Modelica_LinearSystems2.
- Improved handling of arrays of records.
- Automatic differentiation extended for more cases.
- Includes Modelica Standard Library 3.1.
New model libraries
- Vehicle Dynamics - Active Safety Library. A platform for complete systems integration of the driver environment-vehicle-safety systems behavior.
- Modelica_LinearSystems2 library. Used to analyze (e.g. eigenvalues, zeros, controllability, stability) and design (e.g. LQG controllers) linear systems.
- Modelica_StateGraph2 library. Used to model hierarchical state diagrams in combination with any Modelica model.
For more information on Dymola, see http://www.dymola.com.
This article is provided by Dag Brück (Dassault Systèmes/Dynasim) .