Ph.D. Thesis Proposal

By

Etienne Demers Bouchard

(Advisor: Prof. Dimitri N. Mavris)

9:00 AM, Tuesday, January 30th, 2018

Weber Space Science and Technology Building (SST-II)

Collaborative Visualization Environment (CoVE)

Development of a Control Architecture for a Multiple Tethered Aircraft VTOL Concept

ABSTRACT:

Vertical Takeoff and Landing (VTOL) aircraft play an important role in our society by accomplishing a wide range of missions. Many concepts have been proposed to increase the maximum speed of helicopters. This characteristic has usually been conflicting with hover endurance due to the high disk loading typical to high-speed vehicle. However, there has been interest in long endurance flight, highlighted by the AHS International Igor I. Sikorsky 24 Hour Hover Challenge.

Since 2015, there has been renewed effort to study the use of fixed wing aircraft tethered to a load to perform VTOL. The Electric Powered Reconfigurable Rotor (EPR2) aims at leveraging the advantages of electric propulsion to fully explore the potential of this concept. Preliminary studies suggested that the system is expected to perform long endurance missions efficiently, due to the possible low empty weight fraction and the very low equivalent disk loading.

In 2016, Rancourt presented multiple advanced flight paths that efficiently use the degrees of freedom unique to the tethered aircraft to further reduce the power required in hover and to perform advancing flight at high equivalent advance ratio. The inverse dynamics analysis included the dynamic characteristics relevant to the identification of the power required. However, important epistemic uncertainty still remains on the dynamic behavior and controllability of the system.

The present dissertation aims at presenting a methodology to assess the dynamic characteristics of the system and develop a controller for the EPR2 VTOL concept. First, a dynamic simulation environment that incorporates the main characteristics of the system will be developed while consideration is given to complexity and runtime. The open-loop characteristics of the system will then be evaluated for the system in hover. Because some of the system design characteristics and some of the nominal flight path parameters are expected to have an important impact on the dynamics, a method to select them with the system level performance as an objective will be proposed. Finally, with the identified dynamic characteristics as a foundation, a control architecture will be developed.

Committee Members: Dr Dimitri Mavris, Dr JVR Prasad, Dr David Rancourt (Universite de Sherbrooke)