A Trajectory Based Methods for Parallel Scheduling of Machines and AGV’S in an FMS Environment

Abstract

Now a days latest manufacturing sectors facing difficulty with two different categories of processing of parts like semi-finished jobs and finished jobs. In literature it is assumed that, for machine scheduling models, either there is infinite number of handling or carrier systems for the job to reach desired location or jobs are distributed on the spot from one workstation to other without travel time involved. Further it is observed that simultaneous scheduling of machines and AGVs in the FMS environments involves certain exceptional difficulties as they are treated as NP hard problems. Those difficulties are assigning AGV in sequence of task along with operation sequence of machines and operation order of machines based on precedence constraints. Trajectory based methods are powerful metaheuristic for solving combinatorial optimization problems like NP hard problems such as scheduling. In this paper, author addressed about parallel scheduling of machines and AGV’s for determining minimum makespan, mean makespan and tardiness using simulated annealing algorithm and tested over 20 standard benchmark problems collected from literature. Finally, the proposed method is compared with literature results and conclusions are depicted.