Robust control of automated manufacturing systems with assembly operations using petri nets

Abstract

Automated manufacturing systems (AMSs) with complex topologies have become increasingly active in the area of research. However, a prerequisite is indispensable for numerous researchers to investigate AMSs. That is resources are presumptively and arbitrarily assumed never to fail; nevertheless, this does not completely match the reality. In this paper, we consider deadlock and blocking problems in AMSs with unreliable resources and assembly operations. Our objective is to develop a robust supervisory control policy that allocates resources so that parts requiring the failed resource do not block the production of parts not necessarily requiring the failed resource in case any unreliable resource fails unexpectedly. Conventional methods are based on structure-oriented and monolithic specifications. On the contrary, our supervisory policy looks ahead to anticipate whether currently-available resources are enough in their quantity to assist a concerned token to reach its desired destination without knowing the global information. Our strategy is achieved in a local and dynamic manner. It can effectively respond to resource failures.