Hierarchical planning-scheduling-control -- Optimality surrogates and derivative-free optimization
Abstract
Planning, scheduling, and control typically constitute separate decision-making units within chemical companies. Traditionally, their integration is modelled sequentially, but recent efforts prioritize lower-level feasibility and optimality, leading to large-scale, potentially multi-level, hierarchical formulations. Data-driven techniques, like optimality surrogates or derivative-free optimization, become essential in addressing ensuing tractability challenges. We demonstrate a step-by-step workflow to find a tractable solution to a tri-level formulation of a multi-site, multi-product planning-scheduling-control case study. We discuss solution tractability-accuracy trade-offs and scaling properties for both methods. Despite individual improvements over conventional heuristics, both approaches present drawbacks. Consequently, we synthesize our findings into a methodology combining their strengths. Our approach remains agnostic to the level-specific formulations when the linking variables are identified and retains the heuristic sequential solution as fallback option. We advance the field by leveraging parallelization, hyperparameter tuning, and a combination of off- and on-line computation, to find tractable solutions to more accurate multi-level formulations.
Cite
@article{arxiv.2310.07870,
title = {Hierarchical planning-scheduling-control -- Optimality surrogates and derivative-free optimization},
author = {Damien van de Berg and Nilay Shah and Ehecatl Antonio del Rio-Chanona},
journal= {arXiv preprint arXiv:2310.07870},
year = {2023}
}