A six sigma based multi-objective optimization for machine grouping control in flexible cellular manufacturing systems with guide-path flexibility

Effective design of automatic material handling devices is one of the most important decisions in flexible cellular manufacturing systems. Minimization of material handling operations could lead to optimization of overall operational costs. An automated guided vehicle (AGV) is a driverless vehicle used for the transportation of materials within a production plant partitioned into cells. The tandem layout is according to dividing workstations to some non-overlapping closed zones to which a tandem automated guided vehicle (TAGV) is allocated for internal transfers. This paper illustrates a non-linear multi-objective problem for minimizing the material flow intra and inter-loops and minimization of maximum amount of inter cell flow, considering the limitation of TAGV work-loading. For reducing variability of material flow and establishing balanced zone layout, some new constraints have been added to the problem based on six sigma approach. Due to the complexity of the machine grouping control problem, a modified ant colony optimization algorithm is used for solving this model. Finally, to validate the efficacy of the proposed model, numerical illustrations have been worked out.