Bi-Criteria Robotic Cell Scheduling and Operation Allocation in the Presence of Break-downs

This paper focused on scheduling problems arising in a two-machine, identical parts robotic cell, which was configured in a flow shop. Through the current research, a mathematical programming model on minimizing cycle time as well as operational cost, considering the availability of a robotic cell as a constraint, was proposed to search for the optimum allocation and schedule of operations for both two machines. Two solution procedures, including weighted sum method and ε-constraint method, were provided. Based on the weighted sum method, like some previous studies, sensitivity analysis on model parameters was done, and the optimum solutions were compared with previous results, while ε-constraint method could find the Pareto optimal solutions to problems with up to 18 operations in a reasonable time.