Fabrice Pellichero

A multiple objective grouping genetic algorithm for assembly line design

The purpose of this paper is to describe some of the main problems concerning assembly line design. The focus will be on the following steps: (1) the input data preparation, (2) the elaboration of the logical layout of the line, which consists in the distribution of operations among stations along the line and an assignment of resources to the different stations, (3) finally the mapping phase using a simulation package to check the obtained results. This work presents a new method to tackle the hybrid assembly line design, dealing with multiple objectives. The goal is to minimize the total cost of the line by integrating design (station space, cost, etc.) and operation issues (cycle time, precedence constraints, availability, etc.). This paper also presents in detail a very promising approach to solve multiple objective problems. It is a multiple objective grouping genetic algorithm hybridized with the multicriteria decision-aid method PROMETHEE II. An approach to deal with users preferences in design problems is also introduced. The essential concepts adopted by the method are described and its application to an industrial case study is presented.

Applying the equal piles problem to balance assembly lines

The equal piles problem applied to assembly lines seeks to assign assembly tasks to a fixed number of workstations in such a way that the workload on each station is nearly equal. We present a new algorithm to treat this special application of the assembly line balancing problem. The algorithm uses a grouping genetic algorithm (GCA), based on an equal piles approach, and heavily modified with respect the precedence constraints between operations. The main concern is the quality of the resulting line in terms of balancing, and its suitability to the users preferences. The essential and distinct concepts adopted by the method are described along with its step-by-step execution procedure and an illustrative example.

A new philosophy for the design of a product and its assembly line

The main objective of the research presented is to develop a new philosophy for product and assembly line design. Most methodologies usually do not consider the interaction between the two design processes in presence. Moreover, most concurrent engineering approaches do not deal with multi-variant products. A research project was initiated to tackle this problem. The computer tool under development, called CISAL, is applicable to multi-variant products, leading to a unique assembly line for all variants. It is subdivided into three main modules, with possible feedback between them: product analysis, operating modes and assembly techniques, and line layout. We present the framework of this project and the underlying methodology.

Dealing with User's Preferences in Hybrid Assembly Lines Design

Abstract This work presents a new method to address the hybrid assembly line design problem with multiple objectives. The aim is to assign a set of tasks to stations and select the resources to perform each of them. The goal is to minimize the total cost of the line by integrating design and operation issues. The authors used a grouping genetic algorithm to tackle the problem, hybridised with a branch-and-cut algorithm and the multi-criteria decision-aid method Promethee IT. The paper presents the method that assigns tasks to stations and selects assembly equipment for each station. It also introduces the way to deal with users preferences in design problems. The essential concepts adopted by the method are described. The application of the algorithm to an industrial case study is also presented.