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Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006
Frédéric BairFrédéric Bair, ANAST (University of Liege), Belgium, , ANAST (University of Liege), Belgium, [email protected]@ulg.ac.beYves LangerYves Langer, n-Side, Belgium, [email protected], n-Side, Belgium, [email protected] RigoPhilippe Rigo, ANAST (University of Liege), Belgium, , ANAST (University of Liege), Belgium, [email protected]@ulg.ac.be
Modelling, Simulation and Modelling, Simulation and Optimization of a Optimization of a
Shipbuilding WorkshopShipbuilding Workshop
Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006
AAAA
Summary Summary ::
Welding Shipbuilding Workshop (ALSTOM, Welding Shipbuilding Workshop (ALSTOM, « Chantiers de l’Atlantique »)« Chantiers de l’Atlantique »)
Software used: eM-Plant (Tecnomatix)Software used: eM-Plant (Tecnomatix)
Treatment of the huge database (Access)Treatment of the huge database (Access)
Very detailed modelVery detailed model
StochasticStochastic
Optimization: Genetic AlgorithmOptimization: Genetic Algorithm
Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006
Welding Workshop
Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006
Side ASide A- Assembly 1- Assembly 1- Assembly 2- Assembly 2- Assembly 3- Assembly 3- Assembly 4- Assembly 4- Assembly 5- Assembly 5- …- …- Assembly n-1- Assembly n-1- Assembly n- Assembly n
- …- …- …- …- …- …- …- …- …- …- Assembly m- Assembly m
Kit 1
Kit 2
Kit i
Group 1
Group 2
SideSide B B- - Assembly m+1Assembly m+1
- Assembly m+2- Assembly m+2
- Assembly m+3- Assembly m+3
- Assembly m+4- Assembly m+4
- Assembly m+5- Assembly m+5
- …- …
- …- …
- …- …
- …- …
- …- …
- …- …
- …- …
- …- …Group k
Group k+1
Kit j
Kit j+1
Group k+2
Group l
Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006
Objective: minimize production timewith following characteristics :
Assemblies belong to fixed Kit
Kits belong to fixed Group
Orders of groups fixed
Can optimize only position of kits among Groups
Sequence optimization
Useful for Genetic Algorithm (GA)
Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006
2 different sequences (functioning): half-workshop sequence avoid stack up
Half-Cell 1
Half-Cell 2
Half-Cell 3
Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006
Half-cell sequence better to equilibrate both sides (saturation of welding robot)
Half-Cell 1
Half-Cell 2
Half-Cell 3
Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006
Operation Time for each Kit : Preparation – Tacking – Welding –
Finishing
Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006
Other possible results of one simulation:
Occupation Times of welding robots, mechanized gripper, crane bridges, workers
Gantt diagram (for each half-cell)
Total times of each operation (by assembly, by kit, by group)
Storage Times
…
Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006
Optimization:
Genetic Algorithm : 1 individual by a given sequence
Low variance
Not necessary to multiply simulations
Half-cell sequence better than half-workshop sequence
Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006
Evolution of the population :
Gain > 8% between a random sequence and best solution
Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006
Conclusion and perspectives:
Simulation useful even without
optimization
Optimization development Time <
Modelling development Time
Not optimal solution but interesting gains
Automatic Kits creation
