A solution for the shortest time path problem with time-windows of arrival and departure time constraints

The number of automated guided vehicles (AGVs) installed in factories has been increasing annually. It is essential to avoid such interference among AGVs as deadlocks or blockages for efficient operation of many AGVs in a transfer system. This study considers the routing problem in which a certain AGV is requested to arrive at a given destination as soon as possible without any interference. This problem is formulated as a shortest time path problem with time-windows on nodes and arcs of a transfer network. Time-windows are constraints on the arrival and departure time of the requested AGV to avoid interference. In previous studies, time-windows were dealt with as constraints only for the departure time. Therefore their solution algorithm cannot be applied in this problem. We propose a solution algorithm based on a branch-and-bound method.