A constraint programming approach for AGVS flow control

This paper presents a new approach for distributed control of automatic guided vehicle system (AGVS) that uses constraint logic programming formalism to model system operation. The proposed method constructs a feasible schedule by exploiting the constraint propagation mechanism determining the flow of automated guided vehicles. The AGVS is treated as a distributed system composed of autonomous and repetitive processes of automated guided vehicle (AGV) flows. Its periodic behaviour follows from a class of repetitive job shops considered. The approach employs a concept of asynchronous traffic semaphores that provide local mechanism (a dispatching rule) for vehicle flows synchronization. Setting and allocation of particular dispatching rules results in distributed control of vehicle flows possessing self-synchronization features.