Multi-level production scheduling for a class of flexible machining and assembly systems

A class of machining and assembly systems characterised by a flat assembly component structure, and existence of families of similar items, non-negligible setups and fast material flow between work-centres is considered. A hierarchical production scheduling framework is proposed for this class of systems. The decision problems at each level of the hierarchy are identified and formulated. The formulations constitute a sufficiently accurate reflection of reality, while at the same time leading to tractable mathematical models that can be handled by carefully chosen and adapted optimisation techniques. The models can, when combined with suitable knowledge bases form the core of an effective multi-pass, hierarchical decision support system. Possible strategies for coordinating the various decision problems at the different levels of the hierarchy are also discussed.