SysML-based%20Reference%20Models%20for%20Fluid%20Power%20Components

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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

December 6, 2005 www.srl.gatech.edu
www.pslm.gatech.edu
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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

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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

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Semantic Mapping SysML ltgt 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,

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Approach Modelica Profile
Extend Semantics of SysML classes
Extends Association Semantics
Extend Semantics of SysML Types
Note work in progressfeedback welcome
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SysML versions of Modelica Libraries
Use Modelica Profile to Define the Interfacesof
Models in Modelica Libraries
Note work in progress
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Example Hydraulic Motor
The connectors are defined in this parent model
parameters are quantities that remain constant
during a simulation, and are publicly accessible
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Example Hydraulic Motor
(NOTE We have been using Artisan RTS SysML
v0.9)

• Modelica (Dymola)

• SysML (Artisan)

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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 GeneratedModelica Model
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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