Hybrid assembly line design and user's preferences

The paper describes a new method to deal with the hybrid assembly line design, taking multiple objectives into account. It aims to assign a set of tasks to stations and to select the resources to perform each of them, while minimizing the total cost of the line and integrating design and operation issues. A grouping genetic algorithm was developed to solve the problem, hybridized with a branch-and-cut algorithm and the multicriteria decision-aid method PROMETHEE II. The study presents the method used for the allotment of tasks to stations and the determination of the assembly equipment used for each operation. It also introduces a manner to take into account user's preferences 'transparently' in multiple objectives' design problems. The essential concepts adopted in this approach are described and the application of the algorithm to an industrial case study is presented.