Matching Items (6)
Description
As electric powered unmanned aerial vehicles enter a new age of commercial viability, market opportunities in the small UAV sector are expanding. Extending UAV flight time through a combination of fuel cell and battery technologies enhance the scope of potential applications. A brief survey of UAV history provides context and examples of modern day UAVs powered by fuel cells are given. Conventional hybrid power system management employs DC-to-DC converters to control the power split between battery and fuel cell. In this study, a transistor replaces the DC-to-DC converter which lowers weight and cost. Simulation models of a lithium ion battery and a proton exchange membrane fuel cell are developed and integrated into a UAV power system model. Flight simulations demonstrate the operation of the transistor-based power management scheme and quantify the amount of hydrogen consumed by a 5.5 kg fixed wing UAV during a six hour flight. Battery power assists the fuel cell during high throttle periods but may also augment fuel cell power during cruise flight. Simulations demonstrate a 60 liter reduction in hydrogen consumption when battery power assists the fuel cell during cruise flight. Over the full duration of the flight, averaged efficiency of the power system exceeds 98%. For scenarios where inflight battery recharge is desirable, a constant current battery charger is integrated into the UAV power system. Simulation of inflight battery recharge is performed. Design of UAV hybrid power systems must consider power system weight against potential flight time. Data from the flight simulations are used to identify a simple formula that predicts flight time as a function of energy stored onboard the modeled UAV. A small selection of commercially available batteries, fuel cells, and compressed air storage tanks are listed to characterize the weight of possible systems. The formula is then used in conjunction with the weight data to generate a graph of power system weight versus potential flight times. Combinations of the listed batteries, fuel cells, and storage tanks are plotted on the graph to evaluate various hybrid power system configurations.
ContributorsStrele, Thomas (Author) / Nam, Changho (Thesis advisor) / Kannan, Arunachalanadar M (Committee member) / Pollat, Scott L (Committee member) / Arizona State University (Publisher)
Created2016
Energy efficient optimal formation control of a multiple quadrotor UAV system with uncertain payload
Description
This thesis presents the design and simulation of an energy efficient controller for a system of three drones transporting a payload in a net. The object ensnared in the net is represented as a mass connected by massless stiff springs to each drone. Both a pole-placement approach and an optimal control approach are used to design a trajectory controller for the system. Results are simulated for a single drone and the three drone system both without and with payload.
ContributorsHayden, Alexander (Author) / Grewal, Anoop (Thesis director) / Berman, Spring (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Historical, Philosophical & Religious Studies, Sch (Contributor)
Created2022-05
Description
A swarm of unmanned aerial vehicles (UAVs) has many potential applications including disaster relief, search and rescue, and area surveillance. A critical factor to a UAV swarm’s success is its ability to collectively locate and pursue targets determined to be of high quality with minimal and decentralized communication. Prior work has investigated nature-based solutions to this problem, in particular the behavior of honeybees when making decisions on future nest sites. A UAV swarm may mimic this behavior for similar ends, taking advantage of widespread sensor coverage induced by a large population. To determine whether the proven success of honeybee strategies may still be found in UAV swarms in more complex and difficult conditions, a series of simulations were created in Python using a behavior modeled after the work of Cooke et al. UAV and environmental properties were varied to determine the importance of each to the success of the swarm and to find emergent behaviors caused by combinations of variables. From the simulation work done, it was found that agent population and lifespan were the two most important factors to swarm success, with preference towards small teams with long-lasting UAVs.
ContributorsGao, Max (Author) / Berman, Spring (Thesis director) / Pavlic, Theodore (Committee member) / Barrett, The Honors College (Contributor) / College of Integrative Sciences and Arts (Contributor) / Engineering Programs (Contributor)
Created2023-05
Description
Control algorithm development for quadrotor is usually based solely on rigid body dynamics neglecting aerodynamics. Recent work has demonstrated that such a model is suited only when operating at or near hover conditions and low-speed flight. When operating in confined spaces or during aggressive maneuvers destabilizing forces and moments are induced due to aerodynamic effects. Studies indicate that blade flapping, induced drag, and propeller drag influence forward flight performance while other effects like vortex ring state, ground effect affect vertical flight performance. In this thesis, an offboard data-driven approach is used to derive models for parasitic (bare-airframe) drag and propeller drag. Moreover, thrust and torque coefficients are identified from static bench tests. Among the two, parasitic drag is compensated for in the position controller module in the PX4 firmware. 2-D circular, straight line, and minimum snap rectangular trajectories with corridor constraints are tested exploiting differential flatness property wherein altitude and yaw angle are constant. Flight tests are conducted at ASU Drone Studio and results of tracking performance with default controller and with drag compensated position controller are presented. Root mean squared tracking error in individual axes is used as a metric to evaluate the model performance. Results indicate that, for circular trajectory, the root mean squared error in the x-axis has reduced by 44.54% and in the y-axis by 39.47%. Compensation in turn degrades the tracking in both axis by a maximum under 12% when compared to the default controller for rectangular trajectory case. The x-axis tracking error for the straight-line case has improved by 44.96% with almost no observable change in the y-axis.
ContributorsNolastname, Kashyap Sathyamurthy (Author) / Zhang, Wenlong (Thesis advisor) / Yong, Sze Zheng (Committee member) / Berman, Spring (Committee member) / Arizona State University (Publisher)
Created2020
Description
Unmanned Aerial Vehicles (UAVs) have become readily available for both the average consumer and professional due to decreases in price and increases in technological capabilities. This work ventured to explore the feasible use of UAV-technology in the area of roof analysis for facilities management purposes and contrast it to traditional techniques of inspection. An underlying goal of this work was two-fold. First, it was to calculate the upfront cost of investing in appropriate UAV equipment and training for a typical staff member to become proficient at doing such maintenance work in the practice of actual roof inspections on a sample set of roofs. Secondly, it was to compare the value of using this UAV method of investigation to traditional practices of inspecting roofs manually by personally viewing and walking roofs. The two methods for inspecting roofs were compared using various metrics, including time, cost, value, safety, and other relevant measurables. In addition to the study goals, this research was able to identify specific benefits and hazards for both methods of inspection through empirical trials. These points illustrate the study as Lessons Learned from the experience, which may be of interest to those Facilities Managers who are considering investing resources in UAV training and equipment for industrial purposes. Overall, this study helps to identify the utility of UAV technology in a well-established professional field in a way that has not been previously conducted in academia.
ContributorsBodily, Jordan (Author) / Sullivan, Kenneth (Thesis advisor) / Smithwick, Jake (Committee member) / Stone, Brian (Committee member) / Arizona State University (Publisher)
Created2020
Description
Within the scope of Humanitarian Assistance and Disaster Relief (HADR), this thesis reviews some major challenges during mass evacuations, illustrated by incidents during actual mass evacuation scenarios, and identifies several potential applications of autonomous unmanned aerial vehicles (UAVs) in the effort to ease the transition of evacuees out of a disaster area. System requirements and example UAV platforms are identified for applications in which autonomous UAVs monitor traffic conditions along evacuation routes, distribute information to the public, and establish a communications network for first responders.
ContributorsTaylor, Zachary (Author) / Berman, Spring (Thesis director) / Gerber, Brian (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2022-05