Optimality Issues in the Free-Flight Merging of Aircraft.

摘要

This dissertation presents a partial exploration of two fundamentally new paradigms in air traffic control: free flight and decentralization. These ideas are viewed as possible avenues for the next generations of air traffic control systems, which will have to manage a substantially larger amount of traffic.;With the idea of free flight immediately arises the question of trajectory synthesis, and the related issues of optimality, safety, and robustness to uncertain disturbances. The problem of merging aircraft into a single flow (before landing for instance) is a situation where the choice of trajectories is complex, and requires particular attention from the controller. Part I of this thesis presents an algorithmic approach to the synthesis of safe, minimum-turn merging trajectories. The algorithm is based on principles of optimal control theory, and a complete solution to the minimum-turn single-aircraft merging problem is obtained. Examples involving up to five aircraft are treated, and solutions with various degrees of complexity are given. Also, analytical and empirical characterizations of the a priori chances of success of the algorithm are made.;In multi-agent systems, decentralized control introduces several unresolved questions, one of which being the appropriate information topology (possibly constrained) to perform a given task. In Part II of this thesis, a methodology to quantify the relative value of the measurement information at each node of the system is developed for a discrete Linear Quadratic Gaussian framework. Periodicity of the measurements is imposed to interpret the results as data exchange rates, and this assumption allows the reduction of the infinite horizon problem to a finite problem, for which the numerical computations are then feasible. Applied to the classical problem of a string of vehicles, the method results in a topology which is classically valued for its string stability property.;As air traffic increases further. the necessary efforts to redefine the air traffic management system will continue. The work presented in this thesis provides answers to a few of the many questions that will arise along the way, and possibly some inspiration for future research.