Designing a single-vehicle automated guided vehicle system with multiple load capacity

Automated guided vehicle systems (AGVSs) play an important role in today’s factories. When properly designed and controlled they can provide significant cost savings in material handling cost and work-in-process inventory. The authors introduce an analytical approach for the design of a single-vehicle AGVS with multiple load capacity operating under a simple ‘go-when-filled’ dispatching rule. The AGVS supplements an existing non-automated material handling system. It delivers containers with raw material from a central depot to workcenters on the factory floor. The demand of the workcenters and the time until delivery are stochastic. The authors develop a non-linear binary integer progrm to determine which workcenters warrant automated guided vehicle delivery and the consequent path layout subject to constraints on maximum allowable mean waiting time for material delivery. They present an efficient branch-and-bound algorithm that solves the model optimally. Without the analytical solution method, one would have to simulate the system for all possible configurations of open and closed workcenters in order to determine the optimal AGVS design-an approach likely to be infeasible for most problems. The authors also discuss how the present model can be used to design a zoned multiple-vehicle AGVS where each zone is served by a single dedicated vehicle.