PhD Oral Exam - Steven Li, Electrical and Computer Engineering

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

Advanced Air Mobility (AAM) is set to transform urban and regional transportation by shifting the movement of people and goods from the ground to the sky while reducing the environmental impact of aviation. The electrification of aircraft propulsion systems is an important component of this transition. All-electric propulsion offers the potential for zero in-flight greenhouse gas emissions, while hybrid-electric propulsion can provide a pathway toward lower-emission aircraft with greater range and payload capabilities. This thesis focuses on the development of flight management systems and trajectory planning algorithms for the operation of all-electric and hybrid-electric aircraft to minimize operating costs and mitigate air risk in increasingly complex airspace. Three core challenges are addressed. The first challenge is to determine the minimum direct operating cost of an all-electric aircraft in cruise. The second is to establish the conditions under which all-electric operation minimizes the energy cost of a parallel hybrid-electric aircraft in cruise flight. The third is to develop risk-aware trajectory planning approaches that account for the probabilistic risk associated with surrounding air traffic. Numerical simulations demonstrate the influence of various system parameters on the optimal cruise airspeed and the feasibility of all-electric flight. Case studies conducted in collaboration with the National Research Council Canada (NRC), using NAV Canada air traffic data, demonstrate the importance of traffic directionality in estimating air risk and planning trajectories that balance risk and mission duration.