Integrated process planning and scheduling/rescheduling – an agent-based approach

This paper presents a hybrid-based multi-agent system (MAS) for integrating process planning with scheduling/rescheduling in job shops or similar kinds of flexible manufacturing environments. The approach is called Online Hybrid Agent-based Negotiation (oHAN). It employs the affected operations rescheduling approach to reschedule the operations affected directly or indirectly by the disruptions. The proposed MAS architecture comprises local agents, which are the part and machine agents, and a supervisor agent. The local agents detect the production disturbances and reschedule the affected operations via decentralized negotiations. A comprehensive set of process plan flexibilities including flexible routings and alternative machines is considered during rescheduling. The supervisor agent coordinates and monitors the rescheduling process in order to ensure the observance of a global rescheduling objective. An online hybrid contract-net negotiation protocol (oHCNP) has been established to control the interactions and communications among agents. Two types of disturbances, machine breakdown and new part arrival, are investigated in this paper. Extensive experiments have been conducted and the results show that the proposed approach is effective in solving a large-scale rescheduling problem in a reasonable time. With the introduction of the supervisory control into the decentralized negotiations, the hybrid approach is able to provide solutions with a better global performance.