Solving Flexible Job-Shop Scheduling Problem using Hybrid Algorithm Based on Gravitational Search Algorithm and Particle Swarm Optimization

Job Shop scheduling problem has significant importance in many researching fields such as production management and programming and also combined optimizing. Job Shop scheduling problem includes two sub-problems: machine assignment and sequence operation performing. In this paper combination of particle swarm optimization algorithm (PSO) and gravitational search algorithm (GSA) have been presented for solving Job Shop Scheduling problem with criteria of minimizing the maximal completion time of all the operations, which is denoted by Makespan. In this combined algorithm, first gravitational search algorithm finds best mass with minimum spent time for a job and then particle swarm Optimization algorithm is performed for optimal processing all jobs. Experimental results show that proposed algorithm for solving job shop scheduling problem, especially for solving larger problem presents better efficiency. Combined proposed algorithm has been named GSPSO