Multiple agents routing and scheduling algorithms for network-based transportation systems.

This research attempts to develop effective and practical algorithms that enable multiple agents to address routing and scheduling problems simultaneously: given a set of initial points and final points for multiple agents in a route network, separation-compliant routes and speed profiles are to be found for every agent while maximising a performance index subject to satisfy operational constraints. The algorithms are applicable to many transportation systems that consider many operational factors such as flight planning problems in the Air Traffic Management (ATM) system, and analysing urban airspace structure for an Unmanned Aircraft System (UAS) Traffic Management (UTM) system. This thesis focuses on an investigation of a new horizontal Routing and Scheduling (R&S) algorithm for homogeneous multiple arrivals at a single airport. Importantly, this study is the first to investigate the routing problem and scheduling problem simultaneously in the ATM domain, and it is found that a time-based separation concept and a flight time weighting scheme applied in the proposed algorithm allows for horizontal separation-compliant routing and scheduling for each flight. Simulation results show that the current flight planning approach would benefit from the proposed R&S algorithm that provides detailed flight plans in a less computation time. Another part of this thesis focuses on the extension of the R&S algorithm to deal with multiple heterogeneous aircraft arriving at multiple airports, and also to cope with three-dimensional route network. With these extensions, the proposed R&S algorithm can be adopted to handle a wider range of operational conditions represented by various combinations of aircraft types in a fleet and neighbour-dependent separation requirements. Numerical simulation using a simple route network model shows that the R&S algorithm can find the near-optimal route and schedule within polynomial time. As a more realistic case study, we tested the algorithm into the London Terminal Manoeuvring Area (LTMA). The numerical experiment shows that the algorithm provides a separation-compliant route and schedule for multiple heterogeneous aircraft in the three-dimensional LTMA efficiently. By modifying the proposed algorithm, we address flight planning problems that arise in drone delivery, which is one of the most promising applications of the UTM system. As a preliminary study, we demonstrate two last-mile delivery cases (1-to-M) and one first-mile delivery case (M-to-1) within a route network over roads. The results of each case show that detailed flight plans could support analysis of the route network capacity and help to establish requirements for safe and efficient operations. On the basis of this observation, the analysis of the structured urban airspace capacity is performed for four different types of drone delivery operation (1-to-M, M-to-1, N - to-M, and M-to-N ) using the proposed algorithms, where we suggest four intuitive metrics calculated from the detailed flight plans. We apply two different sequencing algorithms (First Come First Served algorithm and Last Come First Served algorithm) - an outer loop of the R&S algorithms - for each operation type. Monte Carlo simulation results suggest to use either more efficient sequencing algorithm or both of the algorithms together in a timely manner for each operation type. From the simulation results, we could expect that the proposed algorithms provide the analysis and suggestions for designing urban airspace to support designers, regulators, and policymakers. Collectively, the algorithms proposed in this thesis may play a key role in many network-based transport planning problems regarding effective and safe operations, along with future works on extension of the algorithm to real-time planning algorithms and to other transportation systems.