An Inter-cell Scheduling Approach Considering Flexible Routes Using Pheromone-Based Agent Negotiation

In practical application, due to the diversification of products and the limited production capacity within units, exceptional some parts have to be processed in different cells. In order to schedule these exceptional parts, collaboration among different cells is needed for integrated production processing path decision.The related work is studied and analyzed first. Based on the actual conditions of manufacturing production, the issue of inter-cell scheduling under flexible routings is proposed. Aiming at the problem of scheduling with exceptional parts that need to visit machines located in multiple job shop cells, a pheromone-based approach (PBA) is proposed in this paper. Multi-agents are used to develop the model of CMS. The negotiation mechanism is based on pheromone derived from ant colony optimization (ACO). Redundant cells are defined and redundant paths are taken out from the flexible processing routes, so that the negotiation range of agents is restricted. Besides, agent coalitions are established to reduce communication cost and to make the solution more global.To our limited knowledge, this is the first paper addressing the intercell scheduling problem using multi-agents. The contribution of this approach includes: considering flexible routes and intercell moves at the same time; allowing dynamic arrival of orders/raw material; restricting the occurrence of intercell moves; and constructing coalitions of agents to improve the global performance and relieve the communication load.Finally, the performance of the approach is evaluated via both therotical analysis and simulation experiments. Simulation results show that compared to the common scheduling rules and their combination, the proposed approach has significant advantages in average flow time, makespan, average tardiness, the ratio of tardy parts, and the ratio of inter-cell moves.