Accommodating FMS Operational Contingencies through Routing Flexibility

Overwhelmed by the complexity of the FMS Deadlock Avoidance problem, current research has, for the most part, ignored the aspects (and benefits) related to flexible (dynamic) job routing. Extending current structural control policies, based on static job routing, to accommodate routing flexibility is nontrivial, primarily due to the fact that the possible routing options for a single job can grow exponentially fast. Hence, computationally efficient techniques are required to incorporate the inherent FMS routing flexibility to current structural control schemes. This paper undertakes the investigation of the problem of integrating routing flexibility in FMS structural control, by addressing the problem of "optimal" job re-routing in case of operational contingencies. Analytical formulations and efficient solution algorithms are developed for the case that the FMS is structurally controlled by a class of recently emerging polynomial-complexity, one-step lookahead deadlock avoid..