Fault tolerant analysis of multi-agent manufacturing systems based Petri nets

Abstract

Holonic manufacturing system (HMS) is a paradigm based on multi-agent system theory that allows fast reconfiguration of available resources to cope with changing product demands in highly uncertain manufacturing environment. The advantage and flexibility offered by HMS poses new challenges and complexities in modeling and design of production control systems. For example, HMS is largely based on multi-agent system (MAS). Contract net protocol is a well-known negotiation and task distribution mechanism for MAS. However, production processes cannot be modeled with contract net protocol. Instead, most existing literatures model production processes based on Petri net theory. The lack of integration among different modeling tools makes it deficient to apply existing tools to model, planning and control HMS. A promising solution to model HMS is to combine the flexibility and robustness of multi-agent theory with the modeling and analytical power of Petri net. This paper focuses on development of a framework to model HMS by extending the contract net protocol with timed Petri net model. The main results include: (1) a nominal collaborative Petri net (CPN) agent model for HMS. (2) Liveness conditions for (CPN) and (3) a resource unavailability model to capture the effects of resource failures. (4) Fault tolerant conditions to test whether a certain type of resource failures are allowed based on Petri net agent model of HMS and (5) a collaborative algorithm to test the feasibility of a solution.