Coupled Vehicle Design and Network Flow Optimization for Air Transportation Systems

1 Abstract Traditionally, the design of a transportation system has focused on either vehicle design or the network ∞ow, assuming the other as given. However, to deflne a system level architecture for a transportation system, it is advantageous to expand the system boundary during the design process to include the network routing, the vehicle speciflcations, and the operations, which couple the vehicle(s) and the network. In this paper, the transportation architecture is decomposed into these fundamental sub-systems by classifying the decisions required to deflne each sub-system. Utilizing an integrated transportation system formulation, the design of the transportation architecture can be obtained by concurrently optimizing the vehicle design and network ∞ow. This is accomplished by embedding a linear programming (LP) solver in the perturbation step of Simulated Annealing in order to solve for the large number of linear constraints imposed by the capacity and demand requirements of the network. The beneflts of this new formulation are illustrated through an example of an air transportation system for an overnight package delivery network where a ten percent improvement in cost is obtained over traditional network-∞ow optimization. The improvement in system cost obtained can be attributed to the reduction in operational ine‐ciencies for the transportation system. Nomenclature