SysML for Automotive Software
Development and Integration
Dr. Arun Chakrapani Rao
Arun.Chakrapani-Rao@warwick.ac.uk
© 2006 IARC
Agenda for this presentation
Background for SysML
Introduction to SysML
Guiding questions for our research
Introduction to Case Study
Discussion of the SysML model
Conclusions
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Background
Systems Modelling Language (SysML) - based on the Unified Modelling
Language (UML).
•
•
UML is a de-facto standard in many industries.
•
Visual language.
•
Simulation features for many diagrams.
•
Automatic code generation through tool vendors.
© 2006 IARC
SysML for Automotive Software Development and Integration
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Limitations and practical problems
•
Language and semantics:
•
large number of diagrams.
Assembly
Use Case
Internal
Block
Block
Defn.
Sequence
State Machine
Class
Activity
Requirement
Timing
•
•
Inadequate for modelling timing constraints.
•
Inadequate for modelling relationships between hardware and software.
Practical usage:
•
Mainly used for high-level requirements capture.
•
Inappropriate use of the language.
•
Issues of model transfer between tools – ex. Rational Rose to I-Logix
Rhapsody.
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Aims of SysML consortium
• Help capture systems information in a precise and efficient
manner to enable integration and reuse in a wider context.
• Help communicate systems information correctly and
consistently among various stakeholders.
• Help analyse and evaluate the system being specified, to
identify and resolve system requirements and design issues, and
to support trade-offs.
© 2006 IARC
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SysML Diagrams
Version 0.9
SysML
Structure
Class
Assembly
Activity
Sequence
Behaviour
Requirement
Timing
State Machine
Parametric
Use Case
Interaction Overview
New
Modified from UML 2.0
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Software tools that support SysML
Tools
•
iLogix Rhapsody
•
ARTiSAN Real-time Studio
•
Telelogic TAU
Important Features
•
Support requirements through to implementation and test.
•
Support SysML diagrams.
•
Add-ons? For scenario-based test and validation; generation of test cases.
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Guiding questions for the research
•
How does SysML support software development?
•
Is the use of SysML only appropriate to a higher level of
abstraction?
•
Is software development possible in a systems engineering
framework?
•
Who needs to know and use which diagrams – as OEM, as
supplier?
•
Will it help produce highly reliable automotive software?
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Case study
4X4i Driver Information
System for a Premium Vehicle
•
Related documentation
W
•
E
•
Requirements specification documents including updates.
•
Documentation and experiences of minor/major problems
faced during the current process of specifying.
•
Conferences, workshops, training and white papers from
websites.
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Requirements Capture
Driver Information System Use Cases
View Navigation
Information
Access Rear
Entertainment
Access Front
Entertainment
Access
4X4iInfo
Driver
Rear
Passenger
Phone
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Refine Use Cases
Refinement of a “Access 4X4i Info” use case:
Access
4X4iInfo
«include»
View Steering
Angle
«include»
View Gear
Position
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Importance/questions – Use Cases
•
clear and concise unlike current documents
•
high-level to refined ones
easy to use items in other diagrams i.e., duplications
reduced
•
•
helps model functionality further, easier to plan V & V
Consistency check in tools– actors connected to use cases
and vice-versa etc.
•
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A generalised platform using assembly diagram
«assembly»
Vehicle Platform 1 Configuration
: Subsys P
: Phone
: Rear Seat
Entertainment
: Bus 3
: Driver InfoSys
Display
: Gateway 2
: Bus 2
: Gateway 1
: Bus 1
:
Steering
Col
: Bus 4
m1 : Bus 4 Msg
m2 : Bus 4 Msg
Bus4 Port
ABS : ECU
Air Sus : ECU
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Different configurations
• Variants
• Optional components
::Vehicle Platform
::Vehicle Platform 1 Configuration
::Vehicle Platform 2 Configuration
Class diagram
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Class diagram
::BUS
::MOST
::CAN
::CAN 11
::LIN
::HS CAN
generalisation - subclass to superclass
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Sequence description (Platform 1)
SCENARIO 1: Mode Change - CD - OFF Road InformationL322
DESCRIPTION: The sequence describes how the user changes from CD mode to OffRoad Compass mode by depressing the OffRoad hard key on the HLDF.
PREREQUISITES: User is listening to CD. DisplayView is CD. 6-Disk CDC Changer
present. Previous Off Road view was Compass. Vehicle is stationary.
SEQUENCE:
User presses OffRoad hard key to request mode change.
User → HLDF: HardKey(OffRoadInfo);
TouchScreenApplication within HLDF internally switches to Off Road View to Compass
(Last used state).
Off Road Information is displayed.
CD is still playing.
End of data flow.
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APPLICABILITY: RADIO
SysML for Automotive Software Development and Integration
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Sequence diagrams (Platform 1)
Platform 1 - Mode Change CD - OffRoad
Driver
Presses OffRoad
System updates
display to
previous OffRoad
...
Front Passenger
OffRoad Button
Touch Screen Display
Driver InfoSys
OffRoad Pressed
Update Display to last OffRoad
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Sequence description (Same functionality, Platform 2)
SCENARIO 2: Mode Change - CD - OFF Road InformationT5
DESCRIPTION: The sequence describes how the user changes from CD mode to OffRoad Suspension mode by depressing the Menu hard key on the HLDF.
PREREQUISITES: User is listening to CD. DisplayView is CD. 6-Disk CDC Changer
present. Previous Off Road view was Suspension. Vehicle is stationary.
SEQUENCE:
User presses Menu hard key to request mode change.
User → HLDF: HardKey(Menu);
TouchScreenApplication within HLDF internally switches to Menu
From Menu screen user presses 4x4i info soft key.
User → HLDF: SoftKey(4x4iInfo);
TouchScreenApplication within HLDF internally switches to Suspension (last used
state)
Off Road Information is displayed.
CD is still playing.
End of data flow.
© 2006 IARC
APPLICABILITY: RADIO
SysML for Automotive Software Development and Integration
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Sequence diagrams (Platform 2)
Platform 2 - Mode Change CD - OffRoad
Driver
Presses Menu
HardKey
Front Passenger
Menu Button
4X4iInfo Button
Touch Screen Display
Driver InfoSys
Menu HardKey Pressed
Update Display to Menu
seq
seq
seq
4X4iInfo SoftKey Pressed
Update Display to last OffRoad
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Sequence diagrams
View steering angle (relates to corresponding use case)
Front Occupant
Presses
4X4iInfo
HardKey
Driver
4X4iInfoButton
Touch Screen Display
Steering Wheel
Driver InfoSys
4X4iInfo HardKey Pressed
If first time
selection
seq
Update Display to Compass View
else
seq
Update Display to last of (VentureCam, Chassis, Compass)
end alt
Driver steers
seq
Steer Left
Update Road Wheel Angle
Information on which parts of
the Driver InfoSys are involved is
shown on a seperate diagram.
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Sequence diagrams
Steering angle information flow through the systems
Touch Screen Display Bus 3
Gateway 2
Bus 2
Gateway 1
Bus 1
steering angle to Bus 1
steering angle to Bus 1
Gateway reads information
{10 ms}
Converted message
gatewayed
steering angle info. displayed
read Bus 1 msg
converted msg to Bus 2
Gateway reads information
Converted message
gatewayed
Steering Col
read Bus 2 msg
converted msg to Bus 3
update steering angle info.
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Conclusions
SysML
• A SysML model could augment
paper specifications
• Assembly diagrams
• Use case, sequence diagrams
• Links to all phases of the system
development lifecycle
OEM
Supplier
Requirement
Use Case
Assembly
Class
Class
Sequence
Sequence
State Machine
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Next Steps
Completion of case study
Results of modelling; evaluations by partners etc.
Define and implement Technology transfer mechanisms
Appropriate training.
Final report on application of the technique
Available to research partners.
Develop recommendations for further research
Comparative study of SysML and alternatives (AADL).
Continuation in new projects
DTI funded Validation of Complex Systems.
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