Post on 17-Jan-2016
Design of Discrete-Event Systems Using Templates
Lenko Grigorov1, José Eduardo Ribeiro Cury2 and Karen Rudie1
1 Queen’s University, Kingston, Canada2 Federal University of Santa Catarina, Brazil
June, 2008 Grigorov, Cury and Rudie, QueensU & UFSC
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Discrete Event Systems
Ramadge and Wonham '86
Model as FSAs
System Supervisor
events
controldecisions
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System
Robotic armPress
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Requirements
Collision prevention Process
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Problem 1: synchronization
Collision prevention Process
Press
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Problem 2: explicit specs
Collision prevention Process
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Supervisors
Trivial example Real system
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Problem 3: implementation
?
Abstract supervisor Programmable Logic Controller(PLC) code for real system
(50 states, 200 transitions)
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Conceptual design framework What we really talk about is
Event generators Protocols
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Conceptual design framework What we really talk about is
Event generators Protocols
Santos et al. '01 Active components Passive components Connections between them Simultaneous structural & functional
design
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Example diagram
Press Arm Welder
Avoid collision
Transport belt
Process control
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Example diagram
Press Arm Welder
Avoid collision
Transport belt
Process control
Event synchronization
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Templates (abstract)
Abstract common behavior
template
abstract
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Templates (instantiate)
Instantiate existing templates
template
instantiate
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Templates
Faster No need to remodel similar behavior
More robust Can be thoroughly tested
Easier Graphical conceptual designs
June, 2008 Grigorov, Cury and Rudie, QueensU & UFSC
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Process
1.Model templates as FSAs
2.Instantiate graphically the templates
3.Link graphically the events to synchronize the template instances
4.Enter custom PLC code for events
5.Click “GO” to automatically Make implicit specifications explicit Compute modular supervisors Obtain PLC code for download to controller
June, 2008 Grigorov, Cury and Rudie, QueensU & UFSC
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1.Model templates as FSAs
2.Instantiate graphically the templates
3.Link graphically the events to synchronize the template instances
4.Enter custom PLC code for events
5.Click “GO” to automatically Make implicit specifications explicit Compute modular supervisors Obtain PLC code for download to controller
Process
June, 2008 Grigorov, Cury and Rudie, QueensU & UFSC
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1.Model templates as FSAs
2.Instantiate graphically the templates
3.Link graphically the events to synchronize the template instances
4.Enter custom PLC code for events
5.Click “GO” to automatically Make implicit specifications explicit Compute modular supervisors Obtain PLC code for download to controller
ProcessControl engineer
Programmer
June, 2008 Grigorov, Cury and Rudie, QueensU & UFSC
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Example application
Methodology used to design controllers for a robotic testbed at DAS, UFSC
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Benefits of thetemplate design methodology Operates in the standard DES
framework Saves time and testing effort Reduces likelihood of errors Facilitates integration of expertise Focuses on conceptual design Supports quick prototyping
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Future work
Improve user interface Focus on fast design prototyping
Conceptual designs with “placeholder” components
Parametrization Scaling of templates
Two-way real-time interaction between DES model and PLC
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