A new bi-objective integrated dynamic cell formation and AGVs’ dwell point location problem on the inter-cell unidirectional single loop

In order to increase the flexibility, space utilization, product quality and safety, transferring the semi-manufactured parts between machines is performed by automated guided vehicles (AGVs). AGVs should be properly managed to maintain their efficiency as a material handling equipment in production systems. This AGVs’ management will be more important where the circumstances will be dynamic (i.e., where the volume and variety of demands are different one period to another). To determine one or several homes for idle AGVs (AGVs’ dwell point), the assignment of AGVs to manufacturing cell and to prevent the AGVs collisions are three basic aspects in their management. This paper proposes a new nonlinear mixed-integer bi-objective mathematical model of dynamic cell formation and dwell point location problem (DCFDPLP) for AGVs on unidirectional single loop in which AGVs assignment, location of dwell points for AGVs and transportation time of AGVs are considered besides cell reconfiguration, part families and machine groups formation in a dynamic environment. The first objective is to minimize the related costs, and the second one is to minimize the maximum response time for all AGVs. The nonlinear model is transformed to linear one. Due to the NP-hardness of DCFDPLP, a non-dominated sorting genetic algorithm (NSGA-II) is developed to solve the problem. Finally, randomly generated test problems are generated to demonstrate the performance of NSGA-II as a solution procedure.