NSF REU-SITE: Unmanned Aerial Systems with Real-World Applications in Oklahoma

Project No. 1

Title: Vision-Based Control of UAS Swarm

Mentor: Dr. Wei Sun

Nowadays many aerial systems (UAs) utilize the fusion of multiple sensors to accurately estimate vehicle position and orientation. These sensors normally include GPS and Inertial Measurement Units and lead to expensive, heavy and complex navigation systems that are not suitable for a swarm of small UAS operating in tricky environments, such as indoor or urban environments where the GPS signals are disrupted. Swarm systems can complete tasks in a collaborative manner that are quite difficult for a single agent to achieve. Furthermore, a swarm of UAS is much more flexible in performing tasks compared to a single agent and is adaptive to both exogenous influence and endogenous disturbance. Objectives: This research aims to develop vision-based navigation and control of a swarm of UAS where each vehicle is mounted with a single camera to generate navigation information for autonomous guidance and control. For the vision-based guidance and control task at hand, the noisy measurements produced by each camera need to pass through a nonlinear filter to estimate the position, velocity and orientation of each UAS. Differences between consecutive camera images and image information collected by neighboring UAS-mounted cameras need to be fused to determine relative states of the UAS, which will then be utilized to control the swarm of UAS. In terms of the control design, a formation control approach, which treats the swarm as a unity or leader-follower and adopts the control strategies developed for a single agent for the swarm, will be utilized. Graph theoretic methods and differential game methods in multi-agent networks need to be explored to achieve coordinated control and collision avoidance of the swarm. The guidance and control scheme of the swarm of UAS developed in this research will first be evaluated in a simulation environment and then validated by Quadcopter flight tests. The flight tests will be performed in the DroneDome at Dr. Sun’s Lab. The REU group will also conduct testing in the open field with an application in mind—package delivery. The team will travel to the Choctaw Nation Unmanned Aircraft System Integration Pilot Program (UASIPP) test site for testing in an open environment. The Choctaw Nation UASIPP test site provides a unique landscape (trees, ponds, wind, large distances between targets, etc.) for the REU team to study the delivery of packages.

Project No. 2

Title: Aerial Sampling of Pollutants (Particulate Matter) from Human Generated Activities

Mentor: Dr. Wilson Merchan-Merchan

REU interns will apply drones to collect particulate matter in an open atmosphere. At OU we have developed and perfected various intrusive techniques for collecting samples of particulate matter (carbon and metal oxide particulates) directly from within the volume of a variety of flame geometries. In recent years, aerial sampling in open atmosphere has been conducted using drones to study gaseous emissions released from human activity into our environment. An innovative approach will be used in this study to sample airborne particulate matter emissions generated from human activity. In the framework of the project, a sampling device will be mounted on a remote-controlled drone and elevated to certain altitudes in the atmosphere to collect samples of soot particulates/urban dust emitted into the atmosphere from combustion and other industrial activities. The sampling device mounted on the drone is composed of an Al disk with double sided carbon tape that serves to trap airborne particulates/emissions. The disk holder assembly securing the Al disk is attached to a lightweight carbon fiber tube to distance the sampler holder from the drone propellers. The REU participants involved in this project will study the physicochemical properties of the collected PM samples (airborne) using low and high transmission electron microscopy (HR/LR-TEM), Electron Energy Loss Spectroscopy (EELS), scanning electron microscopy (SEM) and energy disperse x-ray spectroscopy (EDX). Objectives: The REU team will develop and implement a novel aerial method to collect particulate matter from an open environment. This will be done using a drone and a customized collection device mounted on the drone. Participants will learn the importance of drone payloads (structural & stability aspects), drone control, combustion fundamentals, and fundamentals of electron microscopy. The sampling method designs should be dynamic with adaptive and high-resolution sampling capabilities to function in laminar, transition and turbulent flow environments. REU interns will also have the unique opportunity to work with electron microscopy for sample analysis; they will be exposed to sample preparation, SEM/TEM/EELS/EDX image capturing, and the analysis of the collected images.

Project No. 3

Title: Development and Characterization of Carbon Nanotube-Based Hydrophobic Coatings for Aerospace Ice Mitigation Applications

Mentor: Dr. Jingyao Dai

Due to the critical impact of ice formation on aerospace systems, significant research has focused on developing hydrophobic and superhydrophobic surfaces to reduce water adhesion and mitigate ice accumulation. Surface engineering techniques such as nanoimprint lithography, plasma etching, chemical vapor deposition, and electrospinning have been used to create textured and chemically modified surfaces with enhanced water repellency. More recently, efforts have shifted toward multifunctional coatings that combine hydrophobicity with improved durability, corrosion resistance, scratch resistance, and environmental stability. Carbon-based coatings, particularly carbon nanotube (CNT) films, have shown considerable promise because they provide excellent water repellency while protecting metallic substrates from oxidation and degradation. These multifunctional properties make CNT-based coatings attractive for aerospace applications, including aircraft components, rotor blades, sensors, and unmanned aerial systems operating in cold and humid environments. Objectives: REU participants will work closely with Dr. Dai to fabricate well-aligned carbon nanotube (CNT) coatings on different substrates using a chemical vapor deposition reactor. Students will investigate the relationship between CNT microstructure and hydrophobic performance through scanning electron microscopy and other surface characterization techniques. Hydrophobicity will be evaluated using water contact angle measurements, while a high-speed camera will capture droplet impact and spreading behavior on the engineered surfaces. Coating durability will be assessed by exposing samples to repeated water droplet impacts at different velocities. Environmental performance will also be evaluated through temperature cycling experiments (e.g., 0°C to 120°C) to investigate the effects of thermal expansion, changes in surface morphology, and potential microcrack formation. Contact angle measurements before and after environmental testing will be used to quantify changes in hydrophobic performance and coating durability. Through this project, participants will gain hands-on experience in nanomaterial fabrication, electron microscopy, surface characterization, and environmental testing relevant to next-generation aerospace systems.

Project No. 4

Title: Multifunctional Aerospace Composite Structures Enabled by Aligned Nanotube Arrays

Mentor: Dr. Jingyao Dai

Fiber-reinforced polymer composites are widely used in aerospace structures because of their high specific stiffness and strength. However, conventional composites primarily provide mechanical load-bearing capability and often require separate heaters, sensors, wiring, and thermal-management components to achieve additional functions. Integrating these systems can increase structural weight, manufacturing complexity, and maintenance requirements. Nanomaterials offer a promising approach for creating multifunctional composite structures that combine mechanical performance with heating, sensing, and thermal-management capabilities. In particular, carbon nanotubes (CNTs) possess high aspect ratios, electrical conductivity, and strain-sensitive resistance, making them attractive for resistive heating and structural sensing. Boron nitride nanotubes (BNNTs) provide high thermal conductivity while remaining electrically insulating and may therefore enable heat spreading and thermal management in electrically sensitive structures. When arranged as aligned arrays, CNTs and BNNTs can be applied as lightweight surface coatings or embedded as functional interlayers within composite laminates. Objectives: REU participants will work closely with Dr. Dai to fabricate and characterize multifunctional composite specimens containing aligned CNT or BNNT arrays. The nanotube arrays will be synthesized using an in-house chemical vapor deposition system and examined using optical and scanning electron microscopy to evaluate their alignment, thickness, and uniformity. The arrays will then be transferred onto the surfaces of carbon fiber-reinforced polymer composites or embedded between composite plies during laminate manufacturing. For CNT-enabled specimens, participants will investigate Joule-heating behavior by applying controlled electrical voltage and measuring heating rate, maximum temperature, temperature uniformity, and performance over repeated heating cycles. Infrared imaging or thermocouples will be used to monitor the temperature distribution. The potential of the CNT layers for strain and damage sensing will also be evaluated by measuring changes in electrical resistance during mechanical loading, bending, or repeated deformation. BNNT-enabled specimens will be studied as electrically insulating thermal coatings or interlayers, with emphasis on their effects on heat spreading and thermal response. Cross-sectional microscopy and mechanical testing may be used to assess nanotube integration, interfacial quality, durability, and potential effects on the structural performance of the composite laminates. Through these activities, participants will gain hands-on experience in nanomaterial synthesis, composite manufacturing, microscopy, electrical and thermal characterization, and multifunctional aerospace materials design.

Project No. 5

Title: Design Refinement and Spray Performance Evaluation of a Modular Hexacopter UAV Sprayer System

Mentor: Dr. Srikanth Bashetty

Unmanned aerial systems (UAS) have become valuable tools for precision agriculture by enabling efficient crop monitoring, targeted chemical application, and improved resource management. Compared with conventional ground-based spraying methods, UAV-based spray systems can reduce chemical usage, minimize soil compaction, improve application efficiency, and access areas that are difficult to reach with traditional equipment. As agricultural drones continue to evolve, there is an increasing need for lightweight, modular spray systems that can be integrated with different UAV platforms while maintaining stable flight characteristics and uniform spray performance. Additional research is needed to understand how spray system design, rotor aerodynamics, and nozzle placement affect droplet distribution and application efficiency. Objectives: REU participants will build upon an existing modular spray system designed for integration with a hexacopter UAV. The system has undergone preliminary ground, hover, and indoor flight testing in the University of Oklahoma Drone Dome, but additional design refinement and spray characterization are needed before outdoor deployment. A key objective is the design of a lightweight protective cover to minimize spray drift onto sensitive UAV electronics. Participants will develop computer-aided design (CAD) models, fabricate prototype components using additive manufacturing (3D printing), and integrate the protective cover with the existing spray system. Laboratory experiments conducted in the Drone Dome will evaluate spray pattern uniformity, flow rate, droplet distribution, and overall system performance under different operating conditions. Students will use a patternator to measure the spatial distribution of liquid sprayed by the UAV and determine the coefficient of variation (CV), a key metric for spray uniformity. These measurements will address an important gap in the current project because comprehensive patternator testing has not yet been completed. Experimental results will be compared with numerical simulations performed by a graduate student to improve understanding of UAV spray performance and guide future design optimization. If time, weather, and safety approvals permit, the refined system may also be evaluated at the OPENLAB outdoor testing facility under representative agricultural conditions. Through this project, participants will gain hands-on experience in CAD, additive manufacturing, UAV integration, and spray characterization for precision agriculture.

Project No. 6

Title: Natural Gas Leak Detection Using Unmanned Aerial Vehicle (UAV)

Mentor: Dr. Pejman Kazempoor

REU participants will be exposed to novel/modern technology to quantify natural gas leaks using a drone equipped with a gas sensor. They will learn to design and develop a sensor package mounted onto a drone for detecting and quantifying natural gas leaks. Recent studies show the oil and gas sector leak this potent greenhouse gas far more than previously thought. Unmanned aerial systems can increase the reliability and speed of methane detection and quantification, especially in remote and hazardous locations. The main objective of this project is to develop an aerial-based methane detection platform, including a laser-based sensor (or an infrared camera) and a commercial drone. The expected product will help oil and gas companies protect the environment by detecting harmful leaks. Objectives: The REU team will have an excellent opportunity to work with drones and sensors while learning how the emissions data can be measured, transferred, and interpreted. Interns will be introduced to current practices and future prospects in the field of collecting methane emissions/leaks via an autonomous aerial platform. Currently, the detection of gas leaks using UAS is challenging. The accuracy of this new method is hampered by the limit of UAS payload and measurement interference from the engine’s vibrations. Other non-controllable scenarios that make the application of UAS for this task very challenging is the flow environment (subject to turbulence). Therefore, the REU team working on this task will collaborate with the wind tunnel group to expose the drone to a simulated turbulent flow. The desired end product is a drone capable of detecting gas leaks in less than ideal conditions.

Project No. 7

Title: Optimization of UAV Propeller Performance Using Vortex Generators for High-Altitude and Planetary Applications

Mentor: Dr. Wilson Merchan-Merchan & Dr. Diogo Merguizo Sanchez

As unmanned aerial systems are increasingly considered for high-altitude and planetary exploration missions, the reduction in atmospheric density presents significant challenges for rotor performance. Conventional rotor blades designed for near-sea-level conditions experience reduced lift generation and aerodynamic efficiency in low-density environments. Therefore, the development of optimized blade geometries and lightweight propulsion systems is essential for achieving reliable flight under reduced atmospheric pressure conditions. The application of aerodynamic surface modifications, including vortex generators (VGs) with different shapes and configurations, has been explored as a strategy to improve aerodynamic performance under challenging flow conditions. However, most existing research has focused on airplane wings and large wind turbine blades rather than UAV propeller blades, resulting in limited understanding of VG applications for small-scale aerial vehicles. Objectives: In this project, REU participants will design drone frames by incorporating vortex generators (VGs) on propellers and on supporting structures. The number, arrangement, and configuration of propellers, as well as the geometry and placement of VGs, will be considered during the CAD design and modeling process. Participants will investigate different materials and manufacturing approaches for producing VGs and integrating them onto UAV propellers and frames. The REU team will experimentally evaluate the performance of modified propellers using a Tyto Robotics thrust stand. This testing system will provide measurements of thrust, torque, rotational speed (RPM), voltage, current, and overall propeller performance. Different VG configurations will be compared to determine their influence on propulsion efficiency. To evaluate UAV performance under reduced atmospheric density conditions, the thrust stand and modified propellers will be tested inside a low-pressure environmental chamber to simulate high-altitude Earth conditions and planetary environments with reduced atmospheric pressure. The study will also investigate the effects of low-temperature conditions on UAV performance by exposing the systems to controlled temperature variations representative of high-altitude atmospheric environments. The REU participants will utilize advanced manufacturing techniques, including additive manufacturing and stereolithography, to fabricate drone propellers/VGs based on their designs. Through these activities, participants will gain hands-on experience in UAV design, aerodynamic optimization, additive manufacturing, experimental testing, and environmental simulation. The development of rotor systems capable of operating efficiently under low-density atmospheric conditions is critical for future aerial vehicles, ranging from high-altitude Earth applications to planetary exploration missions such as Mars.

Project No. 8

Title: 3D Printing of Drone Parts Using Sustainable and Lightweight Composites

Mentor: Dr. Yijie Jiang

This project focuses on developing advanced 3D printable composites based on cellulose and food-derived resources for sustainable unmanned aerial system (UAS) applications. Drone components, including propeller blades and structural frames, will be designed, fabricated, and evaluated using these bio-based composites. Three-dimensional (3D) printing has become an important manufacturing technology for producing lightweight, customized components for UASs. While most 3D-printed drone components rely on petroleum-based polymers, growing environmental concerns have increased interest in sustainable alternatives. Cellulose, the most abundant natural polymer, together with food-derived biopolymers such as starch and proteins, offers renewable, biodegradable, and low-cost materials for developing lightweight composite structures with the potential for UAS applications. The development of cellulose- and food-based 3D printed composites is needed to reduce dependence on fossil-based plastics while enabling more sustainable manufacturing of drone components. Advances in bio-based materials and printing technologies can lead to environmentally friendly airframes, payload structures, and mission-specific components that maintain the lightweight characteristics required for UAS performance while promoting sustainable manufacturing and more efficient use of renewable resources. Objectives: The objective of this project is to develop and evaluate 3D printable composites derived from cellulose and food-based resources for lightweight UAS components. Students will formulate and characterize sustainable printable materials, create CAD models of drone components, fabricate prototypes using additive manufacturing, and evaluate their structural and mechanical performance through laboratory testing. Selected components, such as propeller blades and airframe structures, will also be integrated into small UAS platforms for flight testing to assess their performance under realistic operating conditions. Throughout the project, students will gain hands-on experience with computer-aided design, additive manufacturing, material formulation, mechanical characterization, and drone testing. They will also be introduced to a variety of 3D printing technologies, including a hybrid direct ink writing (DIW)-fused deposition modeling (FDM) printer, as well as equipment used for composite preparation, curing, and materials characterization.

Project No. 9

Title: Dynamics and Control of a Low-Cost Quadcopter-Based Reusable Rocket Testbed

Mentor: Dr. Diogo Merguizo Sanchez

Reusable rockets have the potential to significantly reduce the cost of space access and reduce the increasing amount of space debris that endangers satellites and other spacecraft. However, developing and testing reusable rockets can be complex and expensive. On the other hand, Unmanned Aerial Vehicles (UAVs), such as quadcopters, share many similarities in dynamics and control, making them a suitable platform for testing and validating reusable rocket control algorithms, and they are small and lightweight. Therefore, the development of quadcopter-based testbeds can be a cost-effective and efficient way to advance the field of reusable rocket technology. Quadcopter-based testbed approaches vary from using a rigid structure directly attached to the top of the quadcopter to using a pivoting/gimbal-joint configuration and have been used in several works. However, most of these works have focused on developing the quadcopter-based testbed itself rather than developing and validating reusable rocket control algorithms. Objectives: In this project, REU participants will design a simple quadcopter-based reusable rocket testbed, based on the rigid attachment approach, and develop and validate reusable rocket control algorithms using the testbed. The project will involve both theoretical and experimental work, including the design and implementation of control algorithms, the development of a simulation environment, and the testing and validation of the algorithms on the physical testbed. The REU team will evaluate the performance of the developed control algorithms when the quadcopter's center of mass is shifted by changing the position of the payload, which is a common scenario in reusable rocket applications. The mass distribution and size of the payload will vary in the firmly attached structure. The team will use MATLAB/Simulink, specifically the Robotics System Toolbox, to develop a simulation environment for the quadcopter-based testbed and to design and implement the control algorithms. To experimentally evaluate the control algorithm, the REU participants will utilize advanced manufacturing techniques, including additive manufacturing and stereolithography, to fabricate the payload based on their designs. The project will provide an opportunity for REU participants to gain hands-on experience in reusable rocket technology and contribute to the advancement of this important area of research. The development of the Quadcopter-based testbed and the control algorithm is critical for developing new and improved generations of reusable rockets for space exploration.