Multi Agent model based on Chemical Reaction Optimization with Greedy algorithm for Flexible Job shop Scheduling Problem

Scheduling in production systems consists in assigning operations on a set of available resources in order to achieve defined objectives. The Flexible Job shop Scheduling Problem (FJSP) is one of the scheduling problems and also an extension of classical Job shop Scheduling Problem (JSP) such that each operation can be processed on different machine and its processing time depends on the used machine. The FJSP is classified, as most of scheduling problems, NP-Hard in complexity theory and can be decomposed into two sub-problems: a routing sub-problem, which consists of assigning each operation to a machine out of a set of alternative machines, and a scheduling sub-problem, which consists of sequencing the assigned operations on all selected machines in order to attain a feasible schedule with optimized objectives. In this paper, we propose a decentralized model named Multi Agent model based on Chemical Reaction Optimization with Greedy algorithm (MACROG-FJSP) to solve the FJSP in order to minimize the maximum completion time (Makespan). Experiments are performed on well known benchmark instances proposed in the literature which are Fattahi, Kacem, Brandimarte and Hurink instances to evaluate the performance of our model.