Assembly line balancing problems basically consist in assigning a set of tasks to a group of workstations while maintaining the tasks' precedence relations, which are represented by a predetermined precedence graph. However, one or more parts of a product's assembly process may admit alternative precedence subgraphs, which represent possible assembly variants. In general, because of the great difficulty of the problem and the impossibility of representing alternative subgraphs in a precedence graph, the system designer will decide to select, a priori, one of such alternative subgraphs. This paper presents, characterizes and formulates a new general assembly line balancing problem with practical relevance: the Alternative Subgraphs Assembly Line Balancing Problem (ASALBP). Its novel characteristic is that it considers the possibility of having alternative assembly subgraphs, with the processing times and/or the precedence relations of certain tasks dependent on the assembly subgraph selected. Therefore, solving this problem implies simultaneously selecting an assembly subgraph for each part of the assembly that allows alternatives and balancing the line. The potentially positive effects of this on the solution of the problem are shown in a numerical example. Finally, a simple mathematical programming model is described and the results of a brief computational experiment are presented.

http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=04120398International audienceThis paper studies the performance of a group of heuristic methods developed to solve the Alternative Subgraphs Assembly Line Balancing Problem. This problem implies selecting an assembly subgraph for each subassembly that allows alternatives and assigning the tasks to the workstations, simultaneously. A computational experiment is carried out to analyse and compare the efficiency of the proposed procedures considering medium and large scale problems. Test results are reported

International audienceThis paper evaluates a set of constructive heuristic methods developed to solve the novel Alternative Subgraphs Assembly Line Balancing Problem (ASALBP), which considers variants for different parts of a production or manufacturing process. Each variant is represented by a precedence subgraph that defines the tasks to be performed and their processing times. The proposed methods use priority rules and random choice to select the assembly subgraphs and to assign the tasks to the stations in order to minimize the number of required workstations. The methods are evaluated by a computational experiment based on medium- and large-scale benchmark problems