Minimizing the makespan for the problem of reactive production scheduling in a FMS with AGVs using a new structure of chromosome in a hybrid GA with TS

Scheduling of Simultaneous production of machines and AGVs in Flexible Manufacturing Systems involves modeling and searching methodologies in a wide solution space. A criterion often used in the analysis of results for this type of problem is makespan. Many search methods are being used in an attempt to minimize the makespan. This paper has two research objectives. The first consists in verifying the hypothesis that hybridization of a global search (Genetic Algorithm (GA)) with a local search (Tabu Search (TS)) can achieve better results in the problem of reactive scheduling production. The second consists in investigation of a new structure of the GA chromosome for the algorithm has higher correlation with the variable of minimization of the problem, the makespan. This proposal involves modeling tasks in Timed Petri nets during the fitness evaluation, considering the input buffers of machines, AGVs, and control flags for these buffers. The proposal was tested in one scenario of FMS and validated by comparing its results.