a mathematical model for multiple-load agvs in tandem layout

Reducing cost of material handling has been a big challenge for companies. flexible manufacturing system employedautomated guided vehicles (agv) to maintain efficiency and flexibility. this paper presents a new non-linear mathematicalprogramming model to group n machines into n loops, to make an efficient configuration for agv system in tandem layout.the model minimizes both inter-loop, intra-loop flow and use balanced-loops strategy to balance workload in systemsimultaneously. this paper significantly considers multiple-load agvs, which has capability of reducing fleet size andwaiting time of works. a modified variable neighborhood search method is applied for large size problems, which has goodaccuracy for small and medium size problems. the results indicate that using multiple load agv instead of single load agvwill reduce system penalty cost up to 44%.