Modelling, Simulation and Optimization of a Shipbuilding Workshop

1. Modelling, Simulation and Optimization of a Shipbuilding Workshop Frédéric Bair, ANAST (University of Liege), Belgium, F.Bair@ulg.ac.be Yves Langer, n-Side, Belgium, Yves.Langer@ulg.ac.be Philippe Rigo, ANAST (University of Liege), Belgium, Ph.Rigo@ulg.ac.be Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006

2. Summary : • Welding Shipbuilding Workshop (ALSTOM, « Chantiers de l’Atlantique ») • Software used: eM-Plant (Tecnomatix) • Treatment of the huge database (Access) • Very detailed model • Stochastic • Optimization: Genetic Algorithm Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006

3. Welding Workshop Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006

4. Side A - Assembly 1 - Assembly 2 - Assembly 3 - Assembly 4 - Assembly 5 - … - Assembly n-1 - Assembly n - … - … - … - … - … - Assembly m Side B - Assembly m+1 - Assembly m+2 - Assembly m+3 - Assembly m+4 - Assembly m+5 - … - … - … - … - … - … - … - … Kit j Kit 1 Group k+1 Group 1 Kit 2 Kit j+1 Kit i Group k+2 Group 2 Group l Group k Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006

5. Objective: minimize production time • with 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

6. 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

7. 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

8. Operation Time for each Kit : Preparation – Tacking – Welding – Finishing Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006

9. 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

10. 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

11. Evolution of the population : Gain > 8% between a random sequence and best solution Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006

12. Conclusion and perspectives: • Simulation useful even without optimization • Optimization development Time < Modelling development Time • Not optimal solution but interesting gains • Automatic Kits creation Optimization and Engineering – Louvain-La-Neuve – Wednesday May 24th 2006