1. SysML-based Reference Models for Fluid Power Components
Chris Paredis, Raphael Kobi
Product & Systems Lifecycle Management (PSLM) Center
Systems Realization Laboratory
G.W. Woodruff School of Mechanical Engineering
Georgia Institute of Technology
February 14, 2006

2. Reference Models for Fluid Power Components
Aim:
To organize knowledge about fluid power components into standardized, reusable and extensible models
To develop methods for (re-)using this knowledge in support of the design of fluid power systems
Method:
Define an ontology for describing fluid power components and systems
Define reference models as standardized containers that include knowledge and information about the form, function and behavior of components
Formalize the ontology and reference models in SysML
Create semantic mappings between SysML and authoring and analysis tools

3. Initial Focus: Wrapping Modelica Models
Make wrappers of Modelica models available in SysML so that they can be used to create models of new systems
Not the intent to replace Modelica authoring tools (e.g., Dymola)
To use Modelica models, only the interface needs to be available
Includes: Modelica connectors + parameters
Modelica connectors  SysML InternalProperty
Modelica parameters  SysML public value
Note: "parameter" denotes a quantity that remains constant for the duration of a simulation
Other model info is included for completeness
But no semantics – unstructured text

4. Semantic Mapping: SysML <=> Modelica
Modelica is object oriented  many concepts map directly to SysML
Examples:
Modelica class  SysML class
Modelica model SysML block
Modelica partial class  SysML abstract class
But some mismatches due to richer Modelica semantics
Special types of classes: model, record, block, connector, type, package, function
encapsulated class  ??
Modelica Real has attributes: unit, quantity, displayUnit, nominal, fixed, start, min, max, … …

5. Approach: Modelica Profile
Extend Semantics of SysML classes
Extends Association Semantics
Extend Semantics of SysML Types
Note: work in progress…feedback welcome

6. SysML versions of Modelica Libraries
Use Modelica Profile to Define the Interfaces of Models in Modelica Libraries
Note: work in progress…

7. Example: Hydraulic Motor
[… internal definition of ConMot…]
The connectors are defined in this parent model
parameters are quantities that remain constant during a simulation, and are publicly accessible

8. Example: Hydraulic Motor
(NOTE: We have been using Artisan RTS SysML v0.9)
Modelica (Dymola)
SysML (Artisan)

9. Example: Using Motor in Hydraulic Circuit
model VerticalLifter
HyLibLight.Pumps.Tank tank;
HyLibLight.Pumps.ConMot motor;
HyLibLight.Pumps.Basic.IdFlowSource source;
equation
connect(tank.port_A, motor.port_B);
connect(motor.port_A, source.port_B);
end VerticalLifter;
Automatically Generated Modelica Model

10. Next Steps Get feedback from SysML community on semantic mapping
Expand the semantic mapping for
Implement / modify the mapping for updated SysML spec
We will wait for update of spec in Artisan RTS
Implement tool for automatically mapping Modelica XML libraries into SysML wrappers