Job-Shop Scheduling with Robot Synchronization for Transport Operations

We consider a Job Shop Scheduling Problem with transport (JSPT) which consists in jointly scheduling machines and robots. In contrast with the literature, we assume that a transport operation may involve several robots simultaneously, which requires resource synchronization over time. We formulate this problem as a Mixed Integer Linear Programming (MILP) formulation. Then we propose a GRASP-ELS meta-heuristic and a local search procedure where we use a Bierwith’s sequence approach to evaluate a solution. In a numerical study, we have adapted instances from the literature to our problem. The meta-heuristic competes with the exact resolution providing high quality solution in reduced computation time, which lead us to consider that both the modeling and local search are accurate.