SysML-Modelica Transformation Specification

(SE DSIG Meeting, Jacksonville, 3/22/2010)

Chris ParedisGeorgia Tech

On behalf of the SysML-Modelica Working Group1

Presentation Overview

• Objectives, Focus, Scope• What is Modelica?• Transformation

Roadmap• Current Status• Details of Specification• Implementation: Demo• Summary

2

Active Working GroupMembers

• Yves Bernard (EADS)• Roger Burkhart (Deere & Co)• Hans-Peter De Koning (ESA)• Sandy Friedenthal (Lockheed Martin)• Peter Fritzson (Linköping University)• Nerijus Jankevicius (NoMagic)• Alek Kerzhner (Georgia Tech)• Chris Paredis (Georgia Tech)• Axel Reichwein (Georgia Tech)• Nicolas Rouquette (JPL)• Wladimir Schamai (EADS)

Working Group Focus and Scope• Objective:

– Leverage the strengths of both SysML and Modelica by integrating them to create a more expressive and formal MBSE language.

– Define a formal Transformation Specification: a SysML4Modelica profile and a mapping between Modelica and the profile

• Scope:– Cover the Modelica constructs needed for the Modelica

Standard Library to be used in SysML– Generate corresponding SysML constructs that fit within the

profiling mechanism

3

What is Modelica?• State-of-the-art Modeling Language

for System Dynamics– Differential Algebraic Equations (DAE)– Discrete Events

• Formal, object-oriented language• Ports represent energy flow (undirected) or

signal flow (directed)• Acausal, equation-based, declarative• Multi-domain modeling• Standardized by the Modelica Association

4

Modelica: Standard Library

5

mot

or to

rque

Other Modelica Libraries• Modelica association — 20+ free libs (www.modelica.org)• EUROSYSLIB project — 20+ libs under development

(http://www.itea2.org/public/project_leaflets/EUROSYSLIB_profile_oct-07.pdf)

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Roadmap – FutureSysML SysML-Modelica Modelica

December, 2009Initial Draft of Transformation Specification

January 2010Open Source Reference implementations

March June, 2010Submit RFC proposal, AB Approval

March-June June-September 2010Comment period

June September 2010 meetingTF approval

September December 2010 meetingSubmission for adoption

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Current Status

• Draft of Transformation Specification Part I — Introduction final editing Part II — SysML4Modelica profile final editing Part III — Modelica meta-model final editing Part IV — SysML-Modelica mapping

a bidirectional mapping between the SysML4Modelica profile and the Modelica meta-model

ongoing implementation, verification Annex A – Robotic Sample Problemto be completed

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Organization of Transformation

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SysML-Modelica Transformation follows MDA principles

(ormsc/09-02-01: MDA Foundation Model - Santa Clara AB initial comments draft http://www.omg.org/members/cgi-bin/doc?ormsc/09-02-01.pdf)

Presentation Overview• Objectives, Focus, Scope• What is Modelica?• Transformation Roadmap• Current Status• Details of Specification

– Classes, Components, Equations, Connections• Implementation: Demo• Summary

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Two-Tank Example

• Maintain levels at 0.25m and 0.4m• Source produces 0.02 m3/s,

increasing to 0.06 m3/s at time=150s

(From: Peter Fritzson, Principles of Object-Oriented Modeling and Simulation with Modelica 2.1, Wiley-IEEE Computer Society Press, 2003. ) 11

sour...

tank1 tank2piCo... piCo...

Two-Tank Example – Dynamics

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0 100 200 300 400 500

0.0

0.2

0.4

0.6

0.8

1.0 [m

]

tank1.h tank2.h

0 100 200 300 400 5000.0150.0200.0250.0300.0350.0400.0450.0500.0550.0600.065

[m3/

s]

source.qOut.lflow

Modelica Restricted Classes

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Modelica Restricted Classes

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Modelica Restricted Classes —SysML4Modelica Stereotypes

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ModelicaPredefinedTypes

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Modelica Components = Properties• No distinction between types of properties

– record, type «modelicaValueProperty»– connector «modelicaPort»– model, class, block «modelicaPart»– function,

package no usage,only definition

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control

Modelica Components = Properties

18

control

Modelica Components = PropertiesSysML4Modelica Stereotypes

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• Several of these attributes are captured as opaque Modelica expressions

Modelica Components = PropertiesSysML4Modelica Stereotypes

• Several of these attributes are captured as opaque Modelica expressions

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Local Type Modifications

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Local Type Modifications

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Modelica Equations/Algorithms

• Equations– Declarative– Must hold at all times

• Algorithms– Imperative– Must hold at all times– Execute in zero

simulation time23

Modelica Equations/Algorithms —SysML4Modelica Stereotypes

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Modelica Connections

25

Modelica Connections• Alternative:

Leave connect statements in equation section

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Modelica Connections

• parameter N is only known at compilation time

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R=R

resistor1

L=L

inductor1

R=R

resistor2

L=L

inductor2

C=C

capacitor1

G=G

conductor1

C=C

capacitor2

G=G

conductor2

R=R

resistor3

L=L

inductor3

O-Line

Modelica Simulation

• May need to specify additional information:– Solver algorithm– Accuracy

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Tough Issues

• Typing– Structural vs. nominal typing

• Local type modifications– Requires reification– Used extensively — no “instances” in Modelica

• Expressions– Opaque

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Presentation Overview• Objectives, Focus, Scope• What is Modelica?• Transformation Roadmap• Current Status• Details of Specification

– Classes, Components, Equations, Connections• Implementation: Demo• Summary

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Implementation Target 1

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OpenModelicaCompiler

MOFLON TGG

MOFLONgenerated

Java

hand-codedJava

MagicDraw

Implementation Target 2

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OpenModelicaCompiler

QVT

Eclipse

hand-codedJava

MagicDraw /Papyrus

Implementation 3

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OpenModelicaCompiler

Eclipse

hand-codedJava

Papyrus

Acceleo

SysML4Modelica in Context

34SysML4ModelicaAnalytical Model

SysMLDescriptive Model

SysML4Modelica in Context

35

mas

s1

m=1

sprin

g1

fixed1

ModelicaModel

SysML4ModelicaAnalytical Model

SysML Descriptive Modelin Analysis Context

Current Status

• Draft of Transformation Specification Part I — Introduction final editing Part II — SysML4Modelica profile final editing Part III — Modelica meta-model final editing Part IV — SysML-Modelica mapping

a bidirectional mapping between the SysML4Modelica profile and the Modelica meta-model

ongoing implementation, verification Annex A – Robotic Sample Problemto be completed

36

Next Steps

• Complete Reference Implementation– Are the vendors willing to help?

• Final editing + Robot example– Working session on Thursday 9-5 in City Terrace 9

• Review of Spec Document• Workflow for how to use SysML4Modelica

• Submission of RFC– Letters of Intent 37

Discussion?

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