Cooperation schemes for heterogeneous material-handling vehicle fleets

This study deals with an organization which utilizes wire-guided vehicles as its material-handling system and undergoes an expansion; as a result additional material-handling devices are required. In the event, choosing similar vehicles to those currently operating in the manufacturing facility is not a viable alternative, the organization can still decide to maintain a homogeneous vehicle fleet by replacing all vehicles with advanced more expensive free-ranging vehicles. On the other hand, the organization can decide to reuse the old wire-guided vehicles while purchasing only a few new free-ranging vehicles, creating a heterogeneous vehicle fleet. This study presents two different cooperation schemes to control a heterogeneous vehicle fleet, which achieve similar operational performances as a homogeneous fleet of free-ranging vehicles. The study uses simulation to develop control strategies and to determine the system's parameters. Three different scenarios are used to test these control strategies. Finally, an operational and economical comparison analysis between the different cooperation schemes is performed.