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Christian Hammel, Technische Universität Dresden Matthias Schöps, Globalfoundries Dresden. Network Optimization prior to Dynamic Simulation of AMHS. Agenda. Introduction Network model basics Optimization approach Application areas Case study: Introduction Simulation Results.
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Christian Hammel, Technische Universität Dresden Matthias Schöps, Globalfoundries Dresden Network Optimization prior to Dynamic Simulation of AMHS
Agenda • Introduction • Network model basics • Optimization approach • Application areas • Case study: • Introduction • Simulation • Results
Routing in complex AMHS • Mainly based on shortest paths • Mainly static as availability of information is insufficient for dynamic approach • Risk of congestions even without failures shortest path
Common Approach • Manual adjustments of routing • using dynamic simulations • only in selected points • expensively developed and tested • No holistic approach feasible • The bigger the system gets the more time-consuming and difficult this approach
Network Approach source / sink nodes AMHStrack ZFS step 1 step 2 source / sink information attached to links toolports inter-section node links toolqueues • Transfer AMHS network model • Shortest paths easy to find, sophisticated algorithms • No dynamic behaviour
Track Utilization high sources linkutilization mid sinks low • Average transports per unit of time transports as flows • Idea: limit utilization, lower than technical limit because of dynamic behaviour • If all tracks keep this limit: • Congestions because of traffic should be rare • Impacts of failures should be lower (higher robustness)
Traffic Distribution high linkutilization mid low sources sinks • Virtually adjusting lengths (=costs) of links enables manipulating routing with no or minor software changes (and without hardware changes) • Analytic approach to keep all limits not feasible because of run time • Iterative algorithm increasing costs of over-utilized links
Algorithm high utilization mid low + $ • Iteratively increase costs of over-utilized links • Possibilities: • One by one • All over-utilized links at once • Amount to increase depending on over-utilization
Simulation = ? • Network optimization prior to dynamic simulation of AMHS • Gained insights from network analysis also help interpreting simulation behaviour and results
Application Large and complex transport networks • New / adjusted transport layouts • Evaluation of layout alternatives • Analysis of max. TP / bottlenecks • Existing transport systems • Performance improvement without physical modification • Case Study
GF Fab1 Module1 • 51 Stocker with 8120 storage bins • ZFGs with up to 2850 storage bins • Cleanroom area • 14,000m² at level3 • 2,000m² at level1 (Test+metrology area) • Tools direct deliverable by AMHS • 740 at level3 • 15 at level1 • AMHS is ~10 years old system from Murata • ~6.5 km of track • 280 Vehicle (235 then) • ~850 intersections
Iteration Process - 220 tph - 110 tph - 0 tph Iterativelychangingcost factors • Calculate track utilization by adding shortest paths • Increase costs of most used pieces of track (depending on amount of utilization lowering and of mean shortest path length increase)
Validation by Simulation Change in averagetraveldistance: + 4.8 % Change in 95-percentile ofdelivery time in sim.: +/- 0% .. – 20% Change in maximumthroughput in simulation: + 10.9 % Model impact to AMHS by dynamic simulation Original setting Adjusted cost setting
Real System Implementation transports / h DT in mins transport load performance of AMHS date of change Impact on transport performance
Summary • Network approach for traffic distribution in large transport systems • Providing further insight into system behaviour • More general system optimization possible because of • Shorter run time than dynamic simulation • Algorithm is distributing traffic by static routes • Throughput increase by changing routes without physical system modification • No negative impact to transport times
Thank you for your attention! Network Optimization prior to Dynamic Simulation of AMHS Christian Hammel, Technische Universität DresdenTel.: +49 351 463 32539E-mail: christian.hammel@tu-dresden.deMatthias Schöps, Globalfoundries DresdenTel.: +49 351 277 3255E-Mail: matthias.schoeps@globalfoundries.com