Throughput maximization and buffer design of robotized flexible production systems with feeder renewals and priority rules

Automation is a powerful way to reduce production costs. The growing market demand for a wide set of models and small batch production make flexible automated production systems an emerging need in several industries. The aim of this paper is to analyze and to maximize the performance of robotized flexible production systems consisting of a robot, feeder, working station, and unloading station, where the operations of the working cycle are scheduled using a sequencing algorithm based on priority rules. Since the working cycle is not predefined, the cycle time is strongly influenced by the parameters characterizing the workcell such as the workcell layout, the robot transfer movements, the feeder, the working operations, and the presence of a buffer between stations. In this work, we modeled the working cycle of a simple but representative layout of an industrial robotized flexible production system with and without buffer, and we implemented a recursive algorithm to estimate the cycle time. The analytical model derived was compared to the experimental results, obtained by using a prototype of the flexible production workcell. The results show that the analytical model is a powerful tool to estimate the performance of the workcell and to identify the design variables or their combinations that maximize the throughput.