A Hierarchical Modeling Approach for Coordinating Production Operations within a Multi-plant Supply Network

摘要

A hierarchical modelling approach is presented which coordinates the individual plant operations within a multi-plant supply network. The entire decision problem is subdivided into three consecutive stages. In the first stage, the length of the production runs, their timing, the corresponding material flows between the various plants, and equipment requirements have to be determined. At this stage, an aggregation scheme based on the concept of feasibility constraints is employed in order to reflect the limited availability of the various types of production equipment. This concept permits a feasible disaggregation at the lower assignment level. The second stage consists of an assignment model, which allocates the available equipment units between the production runs determined in the first stage of the solution procedure. Finally, resource conflicts are resolved, which may occur if set-up operations and minimal lengths of production runs have to be considered. At this stage, constraint logic programming is applied in order to time-shift individual operations. The proposed hierarchical approach allows a more compact model formulation compared to other approaches known from the literature. As a result, a very efficient and flexible solution procedure is obtained. Its applicability is demonstrated in an industrial application.