Petri Net Modeling Method to Scheduling Problemof Holonic Manufacturing System (HMS) and Its Solutionwith a Hybrid PSO Algorithm

摘要

Holonic manufacturing is a highly distributed control paradigm basedrnon a kind of autonomous and cooperative entity called “holon”. It can bothrnguarantee performance stability, predictability and global optimization ofrnhierarchical control, and provide flexibility and adaptability of heterarchicalrncontrol. In this paper, A new class of Time Petri Nets(TPN), Buffer-nets, forrndefining a Scheduling Holon is proposed, A TPN represents a set of establishedrncontracts among the agents in HMS to fulfill an order. To complete processingrnof orders, liveness of TPNs must be maintained. As different orders may competernfor limited resources, conflicts must be resolved by coordination amongrnTPNs. A liveness condition for a set of TPNs is provided to facilitate feasibilityrntest of commitments.which enhances the modeling techniques for manufacturingrnsystems with features that are considered difficult to model. A schedulingrnarchitecture, which integrates TPN models and AI techniques is proposed. Byrnintroducing dynamic individuals into the reproducing pool randomly accordingrnto their fitness, a variable population-size genetic algorithm is presented to enhancernthe convergence speed of GA. Based on the Novel GA and the particlernswarm optimization (PSO) algorithms, a Hybrid PSO-GA algorithm (HPGA) isrnalso proposed in this paper. Simulation results show that the proposed methodrnare effective for the optimization problems.