Versatile and structurally efficient aerial systems assembled from polyhedral rotorcraft modules

Abstract

Autonomous multirotor vehicles have become widespread tools for many industries. They are used to perform tasks for a fraction of the cost than the traditional methods they supplant and with greater safety. Most payloads carried by drones for current applications are sensors used to gather data in otherwise hard-to-reach places or over large distances or areas quickly. Cargo transportation via autonomous drones is also being explored by several companies, as a mean to provide fast last-mile delivery, for intra-logistics, or to serve remote locations. A few companies have already demonstrated the usefulness of drones to deliver emergency medical supplies to places isolated from transportation networks. The wide variety of drone payloads, from today's numerous sensors to tomorrow's airlifted supplies, and the tight performance envelope of electrically powered platforms result in a myriad of purpose-built vehicles. Modular, reconfigurable autonomous vehicles that can adapt to diverse payloads have been proposed as a replacement of conventional systems for greater flexibility of operations. Because of the necessity to limit interactions between rotors, prior art has been mostly defined by modules that assemble in a horizontal plane.This assembly rule inevitably leads to a decrease in stiffness of vehicles as they grow in size and to several related issues. Novel modular rotorcraft designs and assembly schemes based on polyhedral modules intended to remedy these limitations are explored in this thesis. Structural and dynamical properties of the introduced modular vehicles are studied. In particular, these properties are characterized in a way making the determination of optimal vehicle configurations possible with efficient algorithms. Multiple modular configurations with different capabilities are studied as examples in this thesis. Finally, several prototypes that were designed, fabricated, and flown are presented.