A Robust Formulation for U-shaped Assembly Line Balancing Problem Under Task Time Uncertainty by Considering Worker Skills

2021 ◽

Vol 14 (4) ◽

pp. 733

Author(s):

Nessren Zamzam ◽

Ahmed Elakkad

Keyword(s):

Genetic Algorithm ◽

Assembly Line ◽

Real Life ◽

Assembly Line Balancing ◽

Line Balancing ◽

Initial Population ◽

Time And Space ◽

Task Time ◽

Assembly Line Balancing Problem ◽

Simple Assembly

Purpose: Time and Space assembly line balancing problem (TSALBP) is the problem of balancing the line taking the area required by the task and to store the tools into consideration. This area is important to be considered to minimize unplanned traveling distance by the workers and consequently unplanned time waste. Although TSALBP is a realistic problem that express the real-life situation, and it became more practical to consider multi-manned assembly line to get better space utilization, few literatures addressed the problem of time and space in simple assembly line and only one in multi-manned assembly line. In this paper the problem of balancing bi-objective time and space multi-manned assembly line is proposedDesign/methodology/approach: Hybrid genetic algorithm under time and space constraints besides assembly line conventional constraints is used to model this problem. The initial population is generated based on conventional assembly line heuristic added to random generations. The objective of this model is to minimize number of workers and number of stations.Findings: The results showed the effectiveness of the proposed model in solving multi-manned time and space assembly line problem. The proposed method gets better results in solving real-life Nissan problem compared to the literature. It is also found that there is a relationship between the variability of task time, maximum task time and cycle time on the solution of the problem. In some problem features it is more appropriate to solve the problem as simple assembly line than multi-manned assembly line.Originality/value: It is the first article to solve the problem of balancing multi-manned assembly line under time and area constraint using genetic algorithm. A relationship between the problem features and the solution is found according to it, the solution method (one sided or multi-manned) is defined.

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Robust optimization for U-shaped assembly line worker assignment and balancing problem with uncertain task times

Croatian Operational Research Review ◽

10.17535/crorr.2020.0018 ◽

2020 ◽

Vol 11 (2) ◽

pp. 229-239

Author(s):

Ömer Faruk Yılmaz

Keyword(s):

Robust Optimization ◽

Assembly Line ◽

Assembly Line Balancing ◽

Great Majority ◽

Line Balancing ◽

Worker Assignment ◽

Uncertainty Set ◽

Task Time ◽

Assembly Line Balancing Problem ◽

Water Meters

Awareness of the importance of U-shaped assembly line balancing problems is all on the rise. In the U-shaped assembly line, balancing is affected by the uncertainty associated with the assembly task times. Therefore, it is crucial to develop an approach to respond to the uncertainty caused by the task times. When the great majority of existing literature related to uncertainty in the assembly line is considered, it is observed that the U-shaped assembly line balancing problem under uncertainty is scarcely investigated. That being the case, we aim to fill this research gap by proposing a robust counterpart formulation for the addressed problem. In this study, a robust optimization model is developed for the U-shaped assembly line worker assignment and balancing problem (UALWABP) to cope with the task time uncertainty characterized by a combined interval and polyhedral uncertainty set. A real case study is conducted through data from a company producing water meters.

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