View
224
Download
0
Category
Preview:
Citation preview
PROSA, a reference architecturefor holonic manufacturing systems
dr. ir. Jo Wyns KULeuven / RealSoftware
PMA KULeuven
Jo.Wyns@advalvas.be
http://www.mech.kuleuven.ac.be/~jwyns
the key to support evolution and reconfiguration
Manufacturing control
• logistical planning
• technological planning, late design decisions
• resource allocation
• downloading of NC-programs
• tracking of materials, tools, people, ...
• etc.
=> but broad in space and time
Problem statement
• Disturbances– machine break-down
– rush order
– missing tools
– missing materials
– absenteism
– etc.
• On-line manufacturing control algorithm
• Changes– new technology
– new markets
– new products
– new organisational structures
– etc.
• Manufacturing control system architecture
Reference architecture
Manufacturingcontrol system
System architecture
Referencearchitecture
HW/SW,implementation
blueprint,components,interactions
style, types of components andinteractions
executeabstraction, communication, indicate vital components
reduce development time, increase quality,unif. terminology
buildingplans, sketches, specifications
building style, constructionelements, ...
Wha
tG
oal
Ana
logy
Hierarchical control (ex.)
Heterarchical control (ex.)
Hierarchical vs. heterarchical control
• Every child node has only 1 parent.
• Master - Slave
• Low Adaptability
• Low support for Evolution
• => for large systems
• => not for dynamic systems(changes/disturbances)
• Distributed
• No supervisory control
• Negociation
• No global optimisation
• => for homogeneous systems
• => not for large systems
Holonic manufacturing systems (HMS)
Manufacturing holon
Holon• whole, autonomy• part, co-operation
Stability• decoupling• self-similar
PROSA: basic holons
Basic holons
Holonic Manufacturing System
Order holon
0..*
0..*
Product holon
0..*
1..*
10..*
Resource holon
0..*
1..*1..*
0..*
1..*
0..*
0..*
0..*
0..*
1..*
0..*
1..*
Process knowledgeProcess execution knowledge
Production knowledge
1..*
0..*
10..*
1..*
0..*
Aggregation
• hiding details in aggregated structures
• open-ended at top and bottom
• multiple aggregations (not tree-shaped)
• not static, may change dynamically
• resource, product, order aggregations
Aggregation
Resource holon
0..*0..* 0..*0..* 0..*0..*Equipment holon Shop holon
0..*0..*
Workstation holon0..*0..* 0..*0..* Factory holon
0..*0..*
0..*0..*
0..*0..*
0..*0..*
0..*0..*
0..*0..*
Specialisation
• Different types of resources: – Processing resources, workstations, – Transport resources, transport system– ...
• Different types of orders and products:– Stock orders, customer orders– Different product families
Specialisation
Resource holon
Shop holon Workstation holonEquipment holon
Assembly shop Milling shop
CMM station Milling station Assembly station
Robot NC-machine Conveyor
Staff holons
• Basic holons + aggregation + specialisation– only heterarchical control
(aggregation contains no control functionality)– distributed system
• But ...– centralised problem solving is sometimes easier
(e.g. scheduling)– hierarchical structures in factories
Staff holons
• Expert gives advise to the basic holons
• Holonisch manufacturing system– distributed system:
robust and adaptable– ability for centralised functions
• Behaviour: hierarchical, heterarchical, and mengvormen zijn mogelijk
Staff holons (3)
0..*
1..*
announce work-to-do
0..*
Order holon
provide order schedule
0..1
announce capacity
0..*
Resource holon
0..*
1..*
Process execution knowledge
provide resource schedule
0..1
Scheduler holon
0..*
0..1
0..*
0..1
Flexible assembly system
• Apply PROSA to real machines (robots & PLC)
• Switch between real machines and simulation (virtual factory)
• Logistical decisions– replaceable dynamic market mechanism– reactive centralised scheduler and
schedule execution
Flexible assembly system
Example
Horizontal self-similarity
• Specialisation uses inheritance (OO)
• All kind of resource holons share common interface and behaviour; idem for order holons and product holons
• => Special cases/types can be handles similar to nominal ones
• e.g. rush order; first-of order; high volume vs. high quality product;
Vertical self-similarity
• Holarchy is a resource holon on itself;resource holon can internally be a holarchy
• Homogeneity in internal functioning of holarchies
• Resource holon is independent of holarchy to which it belongs
• e.g. belong to multiple holarchies at the same time (human)
Self-similarity (3)
0..*0..*
0..*0..*
0..*
0..*
Order holon
0..*0..*
0..*0..*
0..*
Resource holon
0..*0..*
0..*
0..* 1..*
Product holon
0..*0..*
0..*
1..*
Conclusion
• PROSA: Product-Resource-Order-Staff Architecture– necessary basic holons– optional staff holons – generalisation of hierarchical and
heterarchical architectures– software framework
Conclusion
• Evolution & reconfiguration– decoupling of control algorithm from system
architecture– decoupling of logistical and technological
aspects– self-similarity
More details on PROSA
• Van Brussel, H., J. Wyns, P. Valckenaers, L. Bongaerts, P. Peeters, (1998) Reference Architecture for Holonic Manufacturing Systems: PROSA, Computers In Industry, Special Issue on Intelligent Manufacturing Systems, Vol. 37, No. 3, pp. 255 – 276.
• Wyns, J. (1999), Reference architecture for holonic manufacturing systems - The key to support evolution and reconfiguration, Ph.D. thesis, ISBN 90-5682-164-4, K.U.Leuven.
• http://www.mech.kuleuven.ac.be/pma/research/hms
• http://www.mech.kuleuven.ac.be/~jwyns
Integration with scheduling
• Planning = advise: – what, when, how?– not: invent standard for planning advise– but: design pattern for integration
• Solution: multiple decision taking algorithms + one selection algorithm in order holons
Integration with scheduling
theOrder : Order
theRAAlgorithm : RAAlgorithmtheRASelectionAlgorithm :
RASelectionAlgorithm
selectedRATask suggestedRATask3: getSuggestion(possibleResource[])
4: select(suggestedRATask[])
aScheduler : Staff systemConfigurator : Staff
1: setRASelectionAlgorithm(RASelectionAlgorithm)
2: addRAAlgorithm(RAAlgorithm)
Man-machine interface
Recommended