Abstract

Global warming has become one of the biggest environmental issues. To reduce its effect on climate change, the aviation industry is constantly looking for ways to decrease fuel emissions of modern airplanes, either by applying new technologies to existing airplane structures or by increasing the aircraft performance in flight. These measures could reduce significantly the fuel consumption of today’s commercial airplanes. Among other solutions proposed by various engineers, the use of renewable energy sources looks especially promising since electric engines could provide near emission-free propulsion.

This thesis proposes an optimal control framework for flight management systems of turbofan and all-electric aircraft. The optimal control problem of economy mode is solved using Pontryagin’s minimum principle. The economy mode optimization problem corresponds to the minimization of a functional parameterized by a coefficient index that performs a trade-off between the cost of fuel or battery charge and time-related costs. For the turbofan, a sub-optimal numerical solution for the true airspeed of an aircraft flying at cruise altitude is obtained. The speed can be easily computed using fast-converging algorithms such as Newton’s method. For all-electric aircraft, an optimal algebraic solution for the true airspeed during the cruise segment is obtained. Additionally, the maximum endurance and the maximum range are obtained as analytical expressions of the parameters.

Overall, the developments presented in this thesis provide a method to obtain the optimal speed schedules for on-board flight management systems of commercial airplanes and also extend the theory of aircraft performance to the case of electric airplanes.