Trade-off between process scheduling and production cost in cyclic flexible robotic cells

In this study, a bi-objective scheduling problem of a flexible robotic cell is considered aiming to a trade-off between cell’s processes scheduling and the production cost. At the cell, machines are identical and parallel and in line. There is an input buffer for the raw materials and an output buffer for the products. A robot is in charge of loading and unloading of the items from the input buffer to machines and from machines to the out put buffer. The system is cyclic means repeats the same processes in every cycle. It is assumed that each machine processes one part in each cycle. A bi-objective mathematical model is presented to solve the problem, and as an alternative, an NSGAII is developed for large-sized problems. Several numerical examples are solved for examining the proposed mathematical model and NSGAII method.