Network flow modeling for flexible manufacturing systems with re-entrant lines
A relaxed version of the steady state material flow planning problem for flexible manufacturing systems/cells (FMS/FMC) such as flexible flow shops and general job shops is formulated using a simple extension of multicommodity network flow problems. Our formulation allows for simultaneous routing and resouce allocation, and also captures the case of re-entrant lines (recirculation). It can be used to perform rapid, albeit crude, explorations of the combinatorial space of possible FMS configurations and of failure scenarios. The technique can also provide bounds on the limits of system performance (eg: throughput, link usage, bottlenecks, etc). This can be used to guide the design of FMS architectures. Our flow based technique can model the transformation of the components from one form to another, as well as their movement from one location to another. Since the flow model ingnores discretization, it solves a less constrained problem, hence it will produce a bound on performance which is always more optimistic than the true optimal. This means that flow model could be used as an admissible heuristic for pruning AI-based planning and scheduling methods.
Hindi, H. ; Ruml, W. Network flow modeling for flexible manufacturing systems with re-entrant lines. IEEE Conference on Decision and Control 2006; 2006 December 13-15; San Diego; CA; USA.