Abstract: A method for determining a node based penalty for use in a path finding algorithm for an automated material handling system (AMHS) is described. The AMHS includes a track interconnecting a plurality of nodes, and on which a plurality of material transport vehicles (MTVs) move. In particular, each of the nodes and MTVs provide queue-blocking data that is stored in a queue-blocking database along with a time tag indicating the time the data was collected. The AMHS retrieves data from the queue-blocking database that has a time tag within a predetermined time window and determines a queue blocking metric for each node in the material transport system. The queue blocking time is converted from to a node based penalty that is the additional distance that an MTV would travel while blocked. Thus, the node based penalty distance is added to the physical distance between a pair of nodes to provide a distance metric indicative of the current traffic conditions.

Abstract: A method for determining a node based penalty for use in a path finding algorithm for an automated material handling system (AMHS) is described. The AMHS includes a track interconnecting a plurality of nodes, and on which a plurality of material transport vehicles (MTVs) move. In particular, each of the nodes and MTVs provide queue-blocking data that is stored in a queue-blocking database along with a time tag indicating the time the data was collected. The AMHS retrieves data from the queue-blocking database that has a time tag within a predetermined time window and determines a queue blocking metric for each node in the material transport system. The queue blocking time is converted from to a node based penalty that is the additional distance that an MTV would travel while blocked. Thus, the node based penalty distance is added to the physical distance between a pair of nodes to provide a distance metric indicative of the current traffic conditions.