Agent-based dynamic integrated process planning and scheduling in flexible manufacturing systems

Process planning and scheduling are important manufacturing planning activities which deal with resource utilisation and time span of manufacturing operations. The process plans and the schedules generated in the planning phase will be modified in the execution phase due to the unforeseen disturbances in the manufacturing systems. This paper deals with a multi-agent architecture of an integrated and dynamic system for process planning and scheduling for multiple jobs. A negotiation protocol is discussed, in this paper, to generate the process plans and the schedules of the manufacturing resources and the individual jobs, dynamically and incrementally, based on the alternative manufacturing processes. The alternative manufacturing processes are presented by the process plan networks discussed in the previous paper [Tehrani etal. 2007. A search algorithm for generating alternative process plans in flexible manufacturing system. Journal of Advanced Mechanical Design, System, and Manufacturing, 1 (5), 706-716], and the suitable process plans and schedules are searched and generated to cope with both the dynamic status and the disturbances of the manufacturing systems. Coordination agents are proposed to generate a suitable assignment of the job agents to the machine tool agents at each step of the negotiation. Simulation software has been developed to carry out case studies, aimed at verifying the performance and it has been integrated with open robot interface network (ORIN) architecture for practical application of the multi-agent system in a real manufacturing system.