Functional Mockup Interface for Tool and Model Interoperability (towards FMI 2.0)

Transcription

1 Functional Mockup Interface for Tool and Model Interoperability (towards FMI 2.0) Bernhard Bachmann, Willi Braun Acknowledgements: MODELISAR Project has been developing FMI. Most slides in this presentation by Martin Otter, Torsten Blochwitz, et al. Also some slides by Azam Zia and Peter Fritzson

2 FMI Motivation 1 Problems / Needs Component development by supplier Integration by OEM Many different simulation tools supplier1 supplier2 supplier3 supplier4 supplier5 OEM? Solution supplier1 supplier2 supplier3 supplier4 supplier5 Reuse of supplier models by OEM: DLL (model import) and/or Tool coupling (co-simulation) Protection of model IP of supplier tool 1 tool 2 tool 3 tool 4 tool 5 FMI OEM Added Value Early validation of design Increased process efficiency and quality supplier1 supplier2! OEM slide from Nick Suyam, Daimler (adapted) supplier3

3 No standards available for: FMI Motivation 2 Model interface based on C or binaries Co-simulation between simulation tools Lots of proprietary interfaces: Simulink: S-function Modelica: external function, external object interface QTronic Silver: Silver-Module API SimulationX: External Model Interface NI LabVIEW: External Model Interface, Simulation Interface Toolkit Simpack: uforce routines ADAMS: user routines Solution: Functional Mockup Interface (FMI) standard

4 Functional Mock-up Interface (FMI) Overview etc. Engine with ECU Gearbox with ECU Thermal systems Automated cargo door Chassis components, roadway, ECU (e.g. ESP) functional mockup interface for model exchange and tool coupling The FMI development is part of the ITEA2 MODELISAR project. ( ; 29 Partner, Budget 30 Mill. ) FMI development is initiated, organized and headed by Daimler AG Improved Software/Model/Hardware-in-the-Loop Simulation, of physical models from different vendors Open Standard 14 automotive use cases for evaluation in MODELISAR courtesy Daimler

5 FMI Main Design Idea A component which implements the interface is called Functional Mockup Unit (FMU) Separation of Description of interface data (XML file) Functionality (C code or binary) A FMU is a zipped file (*.fmu) containing the XML description file and the implementation in source or binary form Additional data and functionality can be included

6 FMI Specifications and Information ( FMI for Model Exchange (Jan. 2010, Version 1.0) Tool FMU Solver Model FMI for Co-Simulation (Oct. 2010, Version 1.0) Tool FMU Model Solver FMI for Model Exchange and Co-Simulation (Nov. 2011, Version 2.0 Beta 3, Release planned for March 2012)

7 FMI for Model Exchange Tool FMU Solver Model

8 FMI for Model Exchange: Export/Import/Simulation Export subsystem model as FMU-archive model description (xml-file) executable dll-file containing model equations optionally C source code Simulation Tool 1 User Interface Sub-system 1 Solver Tool 1 Sub-system 1.fmu Import subsystem model by reading FMU-archive model information from xml-file connecting subsystem variables running system simulation Simulation Tool 2 User Interface Sub-system 2 Subsystem 1.fmu Solver Tool 2

9 Model Distribution as a zip-file (FMU-archive) XML model description file All model information that is not needed during integration of model, e.g., signal names and attributes. Advantage: No overhead for model execution. Tools can read this information (= complicated data structure) with their prefered language (C++, C#, Java,...) Model equations defined by a small set of C-functions. In zip-file: C source code and/or Binary code (DLL) for one or more platforms (Windows, Linux,...) Resources Documentation (html files) Model icon (bitmap file) Maps and tables (read by model during initialization) Sub-system 2.fmu

10 FMU-Archive for Model Exchange XML schema (.xsd) defined by the FMI specification

11 FMI - Interfaces to Simulation Tool Equation structure: robot from Dymola demo

12 FMI - Interfaces to Simulation Tool Piecewise continuous system Continuous and discrete states Event indicators

13 FMI - Interfaces to Simulation Tool

14 FMI - Interfaces to Simulation Tool

15 FMI - Interfaces to Simulation Tool Information not needed for execution is stored in one xml-file: Complex data structures give still simple interface. Reduced overhead in terms of memory. robot from Dymola demo

16 FMI - Interfaces to Simulation Tool Structure of xml-file: Model attributes <?xml version="1.0" encoding="utf8"?> <fmimodeldescription fmiversion="2.0" modelname="mylibrary.examples.friction" guid="{8c4e810f-3df3-4a fa3c9f9e0}"... numberofcontinuousstates="6" numberofeventindicators="34"/>... </fmimodeldescription>

17 FMI - Interfaces to Simulation Tool Structure of xml-file: Model variables <ModelVariables> <ScalarVariable name="inertia1.j" valuereference=" " description="moment of load inertia" simpletype="modelica.siunits.inertia" causality="parameter" variability="fixed"> <Real start="1"/> </ScalarVariable>

18 FMI - Interfaces to Simulation Tool Structure of xml-file: Unit definition unit checking possible mapped on 7 SI base units and derived unit rad <UnitDefinitions> <Unit name="rad"> <BaseUnit rad="1"/> <DisplayUnit name="deg" factor=" "/> </Unit> <Unit name="rad/s"> <BaseUnit s="-1" rad="1"/> </Unit> <Unit name="n.m"> <BaseUnit kg="1" m="2" s="-2"/> </Unit> </UnitDefinitions>

19 FMI for Co-Simulation Tool FMU Model Solver

20 FMI for Co-Simulation Definition: Coupling of several simulation tools Each tool treats one part of a modular coupled problem Data exchange is restricted to discrete communication points Subsystems are solved independently between communication points Motivation: Simulation of heterogeneous systems Partitioning and parallelization of large systems Multirate integration Hardware-in-the-loop simulation

21 FMI for Co-Simulation Master/slave architecture Considers different capabilities of simulation tools Support of simple and sophisticated coupling algorithms: Iterative and straight forward algorithms Constant and variable communication step size Allows (higher order) interpolation of continuous inputs Support of local and distributed co-simulation scenarios FMI for Co-Simulation does not define: Co-simulation algorithms Communication technology for distributed scenarios

22 FMI for Co-Simulation (tool coupling) Use Case Co-Simulation stand alone Co-simulation tool

23 FMI for Co-Simulation (tool coupling) Use Case Distributed co-simulation scenario Data exchange is handled by a communication layer which is implemented by a special FMI wrapper Master and slave utilize FMI for Co-Simulation only

24 FMI - Interfaces for Co-Simulation Equation structure: t, p,inital values (a subset of v( t )) 0 0 Enclosing Co-Simulation Model Master v u y Model t External Model Solver (FMU instance) Co-Simulation Slave (FMU instance) robot from Dymola demo t x x, m, z Solver

25 FMI - Interfaces to Simulation Tool

26 FMI Specifications and Information ( FMI for Model Exchange (Jan. 2010, Version 1.0) Tool FMU Solver Model FMI for Co-Simulation (Oct. 2010, Version 1.0) Tool FMU Model Solver FMI for Model Exchange and Co-Simulation (Nov. 2011, Version 2.0 Beta 3, Release planned for March 2012)

27 Tools supporting FMI (more on FMI web site [currently 33])) AMESim. (export, import, co-simulation (slave)). By LMS CATIA Systems. (all). By Dassault Systèmes. Dymola (all). By Dassault Systèmes. Simulation X. (all). By ITI Systems. SIMULINK. (export, import, co-simulation (master)) via Dymola 2012, Modelon). JModelica.org. (all). By Modelon. Silver/TestWeaver. (import, co-simulation (master)). Qtronic SIMPACK. (all). By SIMPACK OpenModelica. (export, import). By OSMC...

28 FMI Model Exchange and Co-Simulation (not backwards compatible) Documents, schema and header files merged Changes to model variable attributes Variability, Causality, tunable Improvements to unit definition (SI base) Save complete FMU state (Restart of simulation possible) Jacobian matrix (linearization) can be provided as c-function Sparsity pattern of Jacobians can be defined in xml-file Directional derivatives are available (FMU in algebraic loop)

29 Conclusions FMI Advantages over other approaches Advanced co-simulation interface Support for higher order extrapolation/interpolation of interface variables, variable communication step-size, rejecting a communication step. Reliable event handling for hybrid systems Clean state event handling + event iteration over simulation model Reliable and efficient handling of algebraic equations in model. If no convergence of equation solver, model can request step-size reduction in simulator. Solution of equation systems are cached for reuse of subsequent calls. Support for efficient storing results of internal variables Allows to store results of many (e.g ) variables in a practical way. Optimized if e.g. a = b, then only time response of "a" needs to be stored. For Modelica models size of result files is typically reduced by factor 4-5.