Robust control of automated manufacturing systems with flexibility embedded synchronizations using Petri nets

Abstract

Deadlock resolutions have been an active area of research in automated manufacturing systems (AMSs). Most researchers assume that allocated resources do not fail while few of them addresses the discrete-event supervision of AMSs that are subject to resource failures. In practice, resource failures occur unexpectedly in the context of complex system structures, e.g., AMSs with assembly operations and flexible routes. Therefore, we consider robust deadlock-free issue in systems with unreliable resources in this paper. Our objective is to develop a robust supervisory control policy that allocates resources so that parts requiring failed resources do not block the production of parts not necessarily requiring failed resources. To be specific, we hope that concerned parts can advance into the buffer space of an unreliable resource at any time in case the unreliable resource fails. Our approach is distributed, distinguished from conventional methods based on structure-oriented and monolithic specifications. One only concerns about whether currently-available resources are enough in their quantity to assist a concerned token to reach its desired destination.