Towards Unified System Modeling
with the
ModelicaML UML Profile
Adrian Pop, David Akhvlediani, Peter Fritzson
Programming Environments Laboratory,
Department of Computer and Information Science
Linköping University
adrpo@ida.liu.se
EOLT’2007, 2007-07-30
Outline
ƒ Introduction
ƒ System Modeling Language (SysML™)
ƒ Modelica
ƒ ModelicaML: a UML profile for Modelica
ƒ Overview and Purpose
ƒ Diagrams
ƒ Package Diagram
ƒ Class Diagram and Internal Class Diagram
ƒ Equation Diagram
ƒ Simulation Diagram
ƒ Conclusions and Future Work
2
System Modeling Language (SysML™)
ƒ Graphical modeling language for Systems
Engineering constructed as a UML2 Profile
ƒ Designed to provide simple but powerful
constructs for modeling a wide range of systems
engineering problems
ƒ Effective in specifying requirements, structure,
behavior, allocations, and constraints on system
properties to support engineering analysis
ƒ Intended to support multiple processes and
methods such as structured, object-oriented, etc.
3
SysML™ - Diagrams
4
SysML™ - Block Definitions
5
Modelica – General Formalism to Model Complex Systems
Robotics
Automotive
Aircrafts
Satellites
Biomechanics
Power plants
Hardware-in-the-loop,
real-time simulation
ƒ etc
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
6
Modelica – The Next Generation Modeling Language
ƒ Declarative language
ƒ Equations and mathematical functions allow acausal
modeling, high level specification, increased
correctness
ƒ Multi-domain modeling
ƒ Combine electrical, mechanical, thermodynamic,
hydraulic, biological, control, event, real-time, etc...
ƒ Everything is a class
ƒ Strongly typed object-oriented language with a
general class concept, Java & Matlab like syntax
ƒ Visual component programming
ƒ Hierarchical system architecture capabilities
ƒ Efficient, nonproprietary
ƒ Efficiency comparable to C; advanced equation
compilation, e.g. 300 000 equations
7
Modelica Language Properties
ƒ Declarative and Object-Oriented
ƒ Equation-based; continuous and discrete
equations
ƒ Parallel process modeling of concurrent
applications, according to synchronous data flow
principle
ƒ Functions with algorithms without global sideeffects
(but local data updates allowed)
ƒ Type system inspired by
Abadi/Cardelli (Theory of Objects)
ƒ Everything is a class – Real, Integer, models,
functions, packages, parameterized classes....
8
Modelica Acausal Modeling Semantics
ƒ What is acausal modeling/design?
ƒ Why does it increase reuse?
ƒ The acausality makes Modelica classes more
reusable than traditional classes containing
assignment statements where the input-output
causality is fixed.
ƒ Example: a resistor equation:
R*i = v;
ƒ can be used in three ways:
i := v/R;
v := R*i;
R := v/i;
9
Connector Classes, Components and Connections
connector Pin
Voltage v;
flow Current i;
end Pin;
Keyword flow indicates
that currents of
connected pins sums to
zero.
A connect statement in Modelica
connect(Pin1,Pin2)
corresponds to equations:
Pin1.v = Pin2.v
Pin1.i + Pin2.i = 0
Connection between Pin1 and Pin2
10
Modelica - Reusable Class Libraries
R=
C=
L=
Info
Info
G
shaft3DS= shaft3D=
S
S
S
shaft=
gear1=
D
T
:1
+
Op
shaftS=
cylBody=bodyShape=
diff=
bearing
V
gear2=
planetary=
ring=
cyl=
S
moveS
c=
move
torque
fric=
C
y
x
barC2=
force
fricTab
clutch=
a
rev=
univ
planar=
sphere
sphereC
c=
d=
prism=
free
cSer=
C
sensor
lineForce=
r
torque
converter
w
S
S
screw =
barC=
d=
freeS
S
sun=
fixTooth
S
prismS= screw S=
planarS= sphereS
S
S
S
revS=
univS
i
E
cylS=
S
planet=
bodyBar=
inertial
Is
Vs
DC=
AC=
Info
body=
bar=
lineTorque=
advanced
drive
translation
Library
Library
Library
lineSensor
s
sd
t
fixedBase
S
state
11
Graphical Modeling - Drag and Drop Composition
12
Hierarchical Composition Diagram for a Model of a Robot
k2
i
qddRef
qdRef
qRef
1
1
S
S
k1
cut joint
r3Control
r3Motor
i
axis6
tn
r3Drive1
1
qd
axis5
l
qdRef
Kd
S
rel
0.03
Jmotor=J
0.3
sum
w Sum
+1
+1
-
rate2
rate3
b(s)
340.8
a(s)
S
S
iRef
axis4
gear=i
axis3
rate1
tacho2
b(s)
b(s)
a(s)
a(s)
tacho1
PT1
g5
q
qd
axis2
C=0.004*D/w m
Rd1=100
Rp1=200
Rd2=100
-
Ri=10
-
Ra=250 La=(250/(2*D*w m))
Rp2=50
-
Kv
fric=Rv0
pSum
axis1
+
Srel = n*n' + (identity(3) - n*n')*cos(q)
- skew(n)*sin(q);
diff
pow er
+
OpI
wrela = n*qd;
zrela = n*qdd;
Rd4=100
emf
Sb = Sa*Srel';
r0b = r0a;
g3
vb = Srel*va;
g1
wb = Srel*(wa + wrela);
ab = Srel*aa;
hall1
w
zb = Srel*(za + zrela + cross(wa, wrela));
fa = Srel'*fb;
ta = Srel'*tb;
g4
+
Vs
Rd3=100
qRef
joint=0
spring=c
hall2
g2
qd
q
y
x
inertial
r
13
Multi-Domain Modelica Model - DCMotor
ƒ A DC motor can be thought of as an electrical circuit
which also contains an electromechanical component.
model DCMotor
Resistor R(R=100);
Inductor L(L=100);
VsourceDC DC(f=10);
Ground G;
ElectroMechanicalElement EM(k=10,J=10, b=2);
Inertia load;
equation
R
L
connect(DC.p,R.n);
connect(R.p,L.n);
DC
connect(L.p, EM.n);
connect(EM.p, DC.n);
connect(DC.n,G.p);
connect(EM.flange,load.flange);
G
end DCMotor
EM
load
14
SysML vs. Modelica
ƒ SysML
ƒ Pros
ƒ Can model all aspects of complex system design
ƒ Cons
ƒ Precise behavior can be described but not simulated
(executed)
ƒ Modelica
ƒ Pros
ƒ Precise behavior can be described and simulated
ƒ Cons
ƒ Cannot model all aspects of complex system design,
i.e. requirements, inheritance diagrams, etc
15
Outline so far
ƒ Introduction
ƒ System Modeling Language (SysML™)
ƒ Modelica
ƒ ModelicaML: a UML profile for Modelica
ƒ Overview and Purpose
ƒ Diagrams
ƒ Package Diagram
ƒ Class Diagram and Internal Class Diagram
ƒ Equation Diagram
ƒ Simulation Diagram
ƒ Conclusions and Future Work
16
ModelicaML - a UML profile for Modelica
ƒ Supports modeling with all Modelica constructs i.e.
restricted classes, equations, generics, discrete variables,
etc.
ƒ Multiple aspects of a system being designed are supported
ƒ system development process phases such as requirements
analysis, design, implementation, verification, validation and
integration.
ƒ Supports mathematical modeling with equations (to
specify system behavior). Algorithm sections are also
supported.
ƒ Simulation diagrams are introduced to configure, model
and document simulation parameters and results in a
consistent and usable way.
ƒ The ModelicaML meta-model is consistent with SysML in
order to provide SysML-to-ModelicaML conversion and
back.
17
ModelicaML - Purpose
ƒ Targeted to Modelica and SysML users
ƒ Provide a SysML/UML view of Modelica for
ƒ Documentation purposes
ƒ Language understanding
ƒ To extend Modelica with additional design
capabilities (requirements modeling,
inheritance diagrams, etc)
ƒ To support translation between Modelica and
SysML models via XMI
18
ModelicaML - Overview
19
ModelicaML – Package Diagram
ƒ The Package Diagram groups logically connected user
defined elements into packages.
ƒ The primarily purpose of this diagram is to support the
specifics of the Modelica packages.
20
ModelicaML – Class Diagram
ƒ ModelicaML provides
extensions to SysML in order
to support the full set of
Modelica constructs.
ƒ ModelicaML defines unique
class definition types
ModelicaClass,
ModelicaModel,
ModelicaBlock,
ModelicaConnector,
ModelicaFunction and
ModelicaRecord that
correspond to class,
model, block,
connector, function and
record restricted Modelica
classes.
ƒ Modelica specific restricted
classes are included because
a modeling tool needs to
impose their semantic
restrictions (for example a
record cannot have equations,
etc).
Class Diagram defines Modelica
classes and relationships between
classes, like generalizations,
association and dependencies
21
ModelicaML - Internal Class Diagram
ƒ Internal Class Diagram shows the internal
structure of a class in terms of parts and
connections
22
ModelicaML – Equation Diagram
ƒ behavior is specified using Equation Diagrams
ƒ all Modelica equations have their specific diagram:
ƒ initial, when, for, if equations
23
ModelicaML – Simulation Diagram
ƒ Used to model, configure and document simulation
parameters and results
ƒ Simulation diagrams can be integrated with any Modelica
modeling and simulation environment (OpenModelica)
24
Outline so far
ƒ Introduction
ƒ System Modeling Language (SysML™)
ƒ Modelica
ƒ ModelicaML: a UML profile for Modelica
ƒ Overview and Purpose
ƒ Diagrams
ƒ Package Diagram
ƒ Class Diagram and Internal Class Diagram
ƒ Equation Diagram
ƒ Simulation Diagram
ƒ Conclusions and Future Work
25
Conclusions
ƒ ModelicaML – UML profile for Modelica
ƒ Targeted to Modelica and SysML users
ƒ Provides a SysML/UML view of Modelica for
ƒ Documentation purposes
ƒ Language understanding
ƒ extends Modelica with additional design
capabilities (requirements modeling,
inheritance diagrams, etc)
ƒ supports translation between Modelica and
SysML models via XMI
26
Future Work
ƒ integration with Modelica Development Tooling (MDT) and the
OpenModelica Compiler
ƒ Translation between Modelica, ModelicaML and SysML
ƒ Further improvements to ModelicaML specification
27
End
Thank You!
Questions?
Modelica Development Tooling (MDT)
http://www.ida.liu.se/~pelab/modelica/OpenModelica/MDT/
OpenModelica Project
http://www.ida.liu.se/~pelab/modelica/OpenModelica.html
28