1. Introduction to fmi technology
INCOSE-NAFEMS SMSWG Meeting. January 28, 2014
Hubertus Tummescheit, Modelon

2. Overview Modelon: who are we Motivation FMI for Model Exchange
FMI for Co-Simulation
Tools & Interoperability process
FMI 2.0 Outlook
FMI Use Cases
Summary

3. Modelon Overview & Locations
Modelon AB
Lund
Gothenburg
Modelon Inc.
Ann Arbor, MI
Hartford, CT
Modelon KK
Tokyo
Modelon GmbH
Munich
Stuttgart
Hamburg
Global premier provider of Modelica and FMI based solutions for systems engineering
~80 engineers (MSc / PhD levels) dedicated to Modelica and FMI
Global customers mostly among Fortune 500 technology companies in Automotive, Aerospace, Energy and Industrial Equipment
>30% annual organic growth
© Modelon

4. Motivation
Analytic Model Based Systems Engineering: Processes & tools for fully integrated system simulation rapidly evolving
Lack of standards & standardized interfaces
Process inefficiencies: re-work due to lack of interfaces & interoperability
Model deployment expensive
Value Stream Mapping: Missing or fragile interfaces part of most process troubles!

5. We Don’t want to end up in the next edition of this one!
Motivation
We Don’t want to end up in the next edition of this one!
Placeholder: might put a failure video of some sorts in
© Modelon

6. Problem 1
Models of a system often have to be developed using different modeling and simulation environments.
In order to simulate the complete system, the different programs have to interact with each other. ?
supplier1
supplier2
supplier3
supplier4
supplier5
OEM
From the official FMI presentation (adapted)

7. Solution: a standard interface
As a universal solution to this problem the Functional Mockup Interface (FMI) was developed by MODELISAR and is now organized under the umbrella of the Modelica Association. !
supplier1
supplier2
supplier3
supplier4
supplier5
OEM
supplier1
tool 1
supplier2
supplier3
supplier4
supplier5
tool 2
tool 3
tool 4
tool 5
FMI
OEM
One FMU
Inside FMU: IP is protected, compiled model, can be deployed to 3rd parties
From the official FMI presentation (adapted)

8. Walled gardens Current CAE space? FMI helps break down the walls!!
© Modelon

9. Problem 2 Real World example: Construction equipment
System complexity increases while
Required time to market decreases (most industries)
Without disruptive changes, an impossible equation to solve.
Real World example: Construction equipment
50 Engineers involved in design that need models
Very few authoring specialist in a given domain: how can they chare their models?
Hydraulically actuated, mechatronic system: MBS, Hydraulics, Electrical, FEM, Controls, Fluids: Ficticious tool names (specialSim + cost)
250k of software/seat
Source: DARPA AVM pres.

10. Solution: Pervasive use of models
Pervasive use of models in system design are a disruptive change!
Analytic MBSE requires high quality models, from many tools, but CAE tools are expensive
Modelica / 1-D Systems Simulation
CFD
FEA
Sequential tasks have to be executed in parallel
Analysis tasks have to be automated
Block diagrams
FMI-based System Simulation
© Modelon

11. FMI: a business model innovation
FMI-compliant tools often allow liberally licensed export of models for distribution in the organization
Exported FMU’s most often don’t require a license from the model authoring tool
Analytic MBSE can be brought from few simulation specialists to designers, domain specialists, control engineers.
One FMU used by many engineers (control design)
One FMU run on many cores (robust design)
© Modelon

12. THE FMI project Goal of the FMI project in the Modelica Association
From the official FMI presentation (adapted)

13. 1. Model Exchange
Overall goal of the FMI project in the Modelica Association
Model-in-the-loop Software-in-the-loop Hardware-in-the-Loop

14. 2. Tool Interoperability
Model-/Software-/
Hardware-in-the-Loop
Co-Simulation & Tool Interoperability
FEA of brake disc & Tire
Hydraulic System
Chassis
e.g. Dymola
Overall goal of the FMI project in the Modelica Association
e.g. Adams
e.g. Abaqus

15. 3. Enterprise Model Deployment
Any Modelica tool
Standardized deployment of models inside and in-between organizations
Systems
Simulink or Scade
Control
Mechanical
“Daimer, QTronic and Vector describe how Mercedes-Benz currently uses virtual ECUs to validate transmission control software for about 200 variants of the Sprinter series in a highly automated way on Windows PC”

16. FMU: a model with standard interface
A component which implements the FMI standard 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
Information & Interface specification:
From the official FMI presentation (adapted)

17. FMI – two variants FMI for Model Exchange: FMI for Co-Simulation:
Version 1.0 released in January 2010
FMI for Co-Simulation:
Reuses as much as possible from FMI for Model Exchange standard
Version 1.0 released in October 2010
Tool
Solver
FMU
Model
FMU
Model
Solver
Tool
From the official FMI presentation (adapted)

18. XML schema (.xsd) defined by the FMI specification
From the official FMI presentation (adapted)

19. FMI XML Schema
Information not needed during execution is stored in one xml-file:
Complex data structures give still simple interface.
Reduced overhead in terms of memory.
Definition of display units
Definition of type defaults
Default stop time, tol. etc.
Tool specific data
Variable names and attributes
From the official FMI presentation (adapted)

20. C-interface Two C-header files:
Platform dependent definitions (basic types):
C-functions:
18 core functions
6 utility functions
no macros
C-function name: <ModelIdentifier>_<name>, e.g. Drive_fmiSetTime"
From the official FMI presentation (adapted)

21. C-interface
Instantiation: fmiComponent fmiInstantiateXXX(fmiString instanceName, ...)
fmiComponent is a parameter of the other interface functions
Opaque void* for the importing tool
Used by FMU to hold any necessary information.
Functions for initialization, termination, destruction
Support of real, integer, boolean, and string inputs, outputs, parameters
Set and Get functions for each type: fmiStatus fmiSetReal (fmiComponent c, const fmiValueReference vr[], size_t nvr, const fmiReal value[]) fmiStatus fmiSetInteger(fmiComponent c, const fmiValueReference vr[], size_t nvr, const fmiInteger value[])
Identification by valueReference, defined in the XML description file for each variable
From the official FMI presentation (adapted)

22. FMI for Model Exchange
Import and export of input/output blocks (FMU – Functional Mock-up Unit)
Described by
differential-, algebraic-, discrete equations,
with time-, state, and step-events
FMU can be large (e.g variables)
FMU can be used in an embedded system (small overhead)
FMUs can be connected together
From the official FMI presentation (adapted)

23. Signals of a Model Exchange FMU
For example: 10 input/output signals (u/y) for connection and internal variables (v) for plotting
From the official FMI presentation (adapted)

24. Co-simulation Definition: Motivation:
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
Multi-rate integration
Software-in-the-loop simulation
Hardware-in-the-loop simulation
From the official FMI presentation (adapted)

25. 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
From the official FMI presentation (adapted)

26. FMI for Co-Simulation Signals of an FMU for Co-Simulation
Inputs, outputs, and parameters, status information
Derivatives of inputs, outputs w.r.t. time can be set/retreived for supporting of higher order approximation v
t0, p
Enclosing Model
Co-Simulation Master
Solver x t
External Model (FMU instance)
Co-Simulation Slave (FMU instance) t
Model
Solver u y
From the official FMI presentation (adapted)

27. FMI Co-Simulation: Use case
Co-Simulation stand alone:
Co-Simulation tool:
Executable
Library (DLL)
Slave
Model
Solver
Master
Process
Executable
Library (DLL)
Simulation tool
Master
FMI Wrapper
FMI Wrapper
FMI Wrapper
FMI Wrapper
Slave
Model
Solver
Process 1
Process 2

28. FMI for Co-Simulation: 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

29. FMI Development Organization
An independent project under the umbrella of the Modelica Association
Open to anyone that is willing to invest time!
Web site:
All documents, and a standards compliance checker, available for download
Many open source tools available to help vendors implement the standard: BSD-licensed library with basic functionality of the FMI API, developed by Modelon

30. Tools (from FMI website)

31. Cross-checking rules
Standard procedures to ensure compatibility of FMI tools from different vendors
Cross-check table is maintained at fmi-standard.org
Base level compliance: FMI Compliance Checker
Each vendor is encouraged:
Export: provide test FMUs
Import: simulate using test FMUs from other vendors

32. Chassis components, roadway, ECU (e.g. ESP)
Outlook – FMI 2.0
Significant improvements over FMI-ME 1.0 and FMI-CS-1.0
Harmonization - ME and CS specifications are merged
Improved handling of hybrid and discrete models
Efficient interface to Jacobian matrices
Optimization applications (dynamic & steady-state design)
Tunable parameters for interactive simulation
Controller tuning
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
courtesy Daimler

33. FMI Use Cases More FMI Resources: http://www.fmi-standard.org
FMI Tutorial at Modelica conference (March 10-12, Lund Sweden)
FMI 2.0 introduction
FMI for Hardware-In-The-Loop
FMI track at March 11th on Modelica conference
© Modelon

34. Robust Design of Hydraulic Valve
Task: robust design of the dynamic response of a pressure reducing valve (e.g. for fuel supply system)
Tools:
FMU export from Dymola, Hydraulics Library
FMU import into Simulink for open loop stability analysis
FMU interface: FMI Toolbox from Modelon

35. Virtual integration & Test
Silver runs a virtual prototype:
On standard Windows PC
Connecting virtual control and virtual plant using SiL-technology
Using compiled behavioural models from many different tools without sources
Allowing efficient and intuitive communication definition
Allowing simple interaction with the virtual prototype: User “drives” system
Silver allows:
Easy sharing of information/results
Use of simulation technology by non-specialists, without the simulation tool
Protection of IP
System behaviour on the laptop of every engineer (concurrent engineer.)
Extremely fast change-validation- change cycles (few minutes!)
Engineers immediately experience their changes in a system context
FMU export: any FMI compatible tool
FMU import: Silver

36. Coupling Multibody Mechanics to Hydraulics
© Modelon

37. Model Deployment
Model Deployment from Simulation Experts to Reactor Design Experts
Custom-built, pre-packaged work flow based on FMI Excel interface by Modelon
FMU exporter: Dymola
FMU Importer: Microsoft Excel
© Modelon

38. summary
FMI has a high potential being widely accepted in the CAE world:
Initiated and pushed by Daimler to significantly improve the exchange of simulation models between suppliers and OEMs.
Defined in close collaboration of different tool vendors.
Industrial users were involved in the proof of concept.
FMI can already be used with many CAE tools: several Modelica tools, Simulink, multi-body and other tools.
A cost efficient way to deploy models widely
Supported by Industry groups (Global Automotive Alliance Group, GAAG, > 15 Automotive OEM world-wide)
Supported by standards-driving non-profit organization ( as part of PLM standardization)
With material from the official FMI presentation