A declarative approach for AGVs modeling and cyclic scheduling

In this paper, we deal with the cyclic scheduling problem usually observed in the FMS producing multi-type parts where the AGVS plays a role of a material handling system. Finding the conditions guaranteeing the AGVs dead-lock-free and collision-free movement policy is the aim of this work. The AGVs co-sharing the common parts of the transportation route while executing repetitive processes, i.e. being assigned to AGVs passing along machines in a cyclic way, can be modeled in terms of Cyclic Concurrent Process Systems (CCPS). Schedulability analysis for a given CCPS answers the question whether a cyclic schedule exists or not. The paper suggests a novel approach for schedulability analysis employing the declarative modeling. The sufficient conditions guaranteeing CCPS schedulability are discussed and the recursive approach to their designing is proposed.