Performance enhancing strategies for aerial aquatic robotic vehicles
File(s)
Author(s)
Ortega Ancel, Alejandro
Type
Thesis
Abstract
Aerial-aquatic robotic vehicles show great potential to assist in disaster response and envi-ronmental monitoring. However, to undertake these missions they need to overcome thechallenges of large power requirements for take-off, having a relatively short range due toenergy density constraints and the difficulty of operating reliably in air and water. This thesispresents a range of design features and strategies to enhance the capabilities of these roboticvehicles, offering solutions to these challenges.Firstly, the use of superhydrophobic surfaces to help overcome these challenges isanalysed. A variety of superhydrophobic surfaces were manufactured, including lasermicro-machined brass presenting a contact angle of up to 172.4°. The tested surfaces werefound to provide friction reduction of up to 15% in channel flow. In addition, applyinga superhydrophobic surface to the hull of a sailing-flying robot was found to result in adrag reduction averaging 45% in the hydroplaning regime, reducing the take-off powerrequirements as well as increasing range. On the other hand, air-water transition experimentswith projectiles found that neither these surfaces nor their shape significantly affected theirdrag for the conditions tested.Moreover, a propulsion system was integrated into a robotic vehicle to demonstratemultiple continuous jet gliding sequences over a body of water, by reacting a solid fuelsource with the surrounding water to achieve a jet-gliding distance of 26 metres per flight.Furthermore, shape morphing was implemented on a robot to enable it to extend its missionby harnessing energy from the environment. The advantages of shape morphing are furtheranalysed by studying the aerodynamics of a variety of butterfly wings as they change theirconfiguration. The performance enhancing strategies presented can be used to overcome thechallenges of large power requirement, low range and reliability for aerial-aquatic vehicles,expanding their capabilities and laying the foundation for further research in this area.
Version
Open Access
Date Issued
2019-08
Date Awarded
2020-02
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Kovac, Mirko
Sponsor
Engineering and Physical Sciences Research Council
Publisher Department
Aeronautics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)