Process Dynamics-Aware Flexible Manufacturing for Industry 4.0.

This paper studies the following basic flexible manufacturing problem: Given N machines that can perform the same job on a production item (e.g., drilling or tapping) but with different capabilities (e.g., energy requirements and speeds), what is an optimal schedule for the job on these machines? While this is a well-studied problem, the main innovation this paper introduces is the explicit modeling of the underlying process dynamics-i.e., the physical interaction of the item and the machine-using differential equations. The resulting scheduling problem is in a hybrid systems setting that involves determining the transition times between states, where the system evolution in each state is defined by differential equations. To the best of our knowledge, such a cyber-physical systems (CPS) oriented approach to machine scheduling has not been studied before, although it lies at the core of flexible manufacturing in Industry 4.0. We believe that this new formulation might lead to a renewed interest in machine scheduling problems, but now in a hybrid/CPS-oriented setting.