Hierarchical route control in DCV-based baggage handling systems

Modern baggage handling systems transport baggage at high speeds, on track networks, using Destination Coded Vehicles (DCV). To ensure optimal DCVs routing, we propose a hierarchical control framework that consists of local switch controllers providing switch position instructions and a supervisory network controller. The routing control problem for the network controller is a nonlinear optimisation problem with high computational requirements. Therefore, we present an alternative approach for reducing the computational complexity by approximating the nonlinear optimisation and rewriting it as a Mixed Integer Linear Programming (MILP) problem. The advantage is that for MILP problems solvers are available that can efficiently compute the global optimal solution. The MILP solution is then used for computing optimal switch control actions. For a benchmark case study we compare the hierarchical route control with previously developed switch control approaches. Results indicate that the proposed hierarchical control offers a balanced trade-off between optimality and computational effort.