Exploiting Process Dynamics in Multi-Stage Schedule Optimization for Flexible Manufacturing.

The core idea of flexible manufacturing is adapting to changes. In this domain, the machine is not confined to a single fixed type of process but can perform different jobs (e.g., cutting, drilling) in different ways (e.g., varying speed, tool, power consumption). This adaptability should be enabled by a detailed view of how the machines work. The idea is to perform machine scheduling by exploiting the dynamical models-expressed as differential equations-of manufacturing processes, i.e., both machines and production items. The main innovation in this paper is the ability to compute a machine's schedule where the state of the product does not linearly evolve in time but is determined by the set of differential equations instead. Finding the schedule is defined as a multi-objective optimization problem-manufacturers may seek a trade-off between processing time, energy consumption, and other cost functions. The proposed optimization is evaluated using accurate process models, exemplifying how it works and harnesses the expressiveness of differential equations.