Reference:
A.N. Tarau,
B. De Schutter, and
J. Hellendoorn,
"Hierarchical route control in DCV-based baggage handling systems,"
International Journal of Services Operations and Informatics,
vol. 6, no. 1/2, pp. 5-29, Jan. 2011.
Abstract:
State-of-the-art baggage handling systems transport the baggage at
high speeds, on a network of tracks, using destination coded vehicles
(DCV). In order to ensure the optimal routing of DCVs, in this paper
we propose a hierarchical control framework. In this framework switch
controllers provide position instructions for each switch in the
network. The switch controllers are then supervised by a so-called
network controller that mainly takes care of flows of DCVs. The
routing control problem for the network controller is a nonlinear,
mixed integer optimization problem, with high computational
requirements, which makes it intractable in practice. Therefore, we
present an alternative approach for reducing the complexity of the
computations by approximating the nonlinear optimization problem and
rewriting it as a mixed integer linear programming (MILP) problem. The
advantage is that for MILP problems solvers are available that allow
us to efficiently compute the global optimal solution. The solution of
the MILP problem is then used for computing optimal switch control
actions. For a benchmark case study we compare the hierarchical route
control with switch control approaches that have been developed
previously. Results indicate that the proposed hierarchical control
offers a balanced trade-off between optimality and computational
efficiency.