Abstract
Developments in lightweight computer and battery technology are beginning to usher in a new age of high speed delivery through the use of unmanned aerial vehicles, or drones. The near instantaneous communication potential of the internet has resulted in an increasingly high speed world, and there is little doubt that drones will be pressed into service as last mile package delivery tools in order to match this fast pace. Due to the novel nature of the technology, however, there is little prior knowledge on its most effective implementation. This poses a series of important questions for those designing and fielding drones: first and foremost, how can they be designed to maximize package delivery utility while minimizing negative impact on the public? The question of utility ultimately becomes one of monetary value and profit for the companies designing and fielding the drones: what is the cheapest, fastest, most energy efficient vehicle capable of delivering products to customers. Minimizing negative impact is a less straightforward process, as it is a more multifaceted problem. One of these impacts will be noise. Noise has the potential to wreak havoc on the physical and mental wellbeing of those who experience it and, depending on their design, large scale drones are capable of producing more than enough noise to effect individuals. The other impacts may be equally important, but are beyond the scope of this thesis.
This technical project revolved around designing a package delivery drone capable of flying a five pound package up to ten miles away. This weight was chosen because the majority of packages shipped in the United States, particularly those with purchasers who would be interested in near-instantaneous shipping, weigh less than five pounds. Additionally, the range was chosen in order to satisfy the needs of as large an area as possible without requiring a prohibitively large power source. This range is also sufficient to cover the majority of urban areas effectively. The project was performed iteratively, starting with a thorough study of existing literature on drone designs and on the designs of competing package delivery drones. From this study it was determined that the most energy-efficient design would feature tilting wings such that the vehicle could take off vertically and cruise horizontally utilizing lift from wings. From this point the design was refined, including the selection of batteries, motors, and airfoils that would produce a stable and energy efficient craft capable of fulfilling mission requirements. This process was, again, performed iteratively, utilizing CFD software to simulate the in flight performance of the aircraft with various design specifications and components. The final design resulted in a powerful vehicle capable of performing up to and beyond requirements, at the expense of a large final size.
The STS research project focused on a single, albeit still significant, element of drone design and how it could impact human population: aircraft noise. This study was motivated by existing research which found that drone noise could be as, if not more, irritating at a given volume than other sources of noise and that noise of any kind could have significant health and mental wellbeing effects on people, particularly vulnerable groups such as the elderly and mentally ill. By evaluating research performed on individual elements of the drone noise problem, including how many drones may be used, how much noise each drone produces, what the impact of noise is on a person in different environments, and how groups have historically responded to noise pollution, a thorough synthesis was performed. The final results of this project found that, in their current form, drones pose a substantial risk to the wellbeing of vulnerable individuals and to the economic output of urban areas. Individual drones at altitudes above 300 feet are unlikely to have a noticeable impact on those at ground level, but the noise experienced at similar elevations, or near packs of multiple drones, may be significant enough to disrupt sleep at night or workplace productivity during the day. This suggests that there is sufficient risk to elicit a response from at least drone designers and operators, if not also a regulatory response, such as noise ordinances restricting volume or the timing of noise.
Overall, this thesis represents a significant increase in the understanding of package delivery drones, particularly their acoustic impact. The technical thesis proposes a viable design for package delivery drones which can be used in comparisons against radically different designs or to adapt into something even more successful. The research paper assessed the risks that drone noise may present, found that they could be significant for certain populations and gave recommendations for solutions to the problem. In the future, additional research should be performed on specific drone designs, improving on the delivery capabilities to the point of a product that can be used in the field. Then this design should be assessed acoustically using information produced during testing, in a similar manner as this paper, to determine exactly what regulation is necessary for the vehicle to be safe.
Notes
School of Engineering and Applied Sciences
Bachelor of Science in Aerospace Engineering
Technical Advisor: James McDaniel
STS Advisor: Kent Wayland
Technical Team Members: David Normansell, Cristhian Vasquez, Brett Brunsink, Henry Smith III, Timothy Mather, Daniel Choi, Derrick Devairakkam, Gino Giansante, JD Parker, Joseff Medina, Justin Robinson, Philip Hays, Alejandro Britos
