PhD, University of Cincinnati, 2020, Engineering and Applied Science: Aerospace Engineering

A novel approach to parameterize and solve for optimal satellite attitude state trajectories is presented. The optimal trajectories are parameterized using fuzzy inference systems (FISs), and the FISs are optimized using a genetic algorithm. Eight different constrained optimization problems are solved. The objective of each optimization problem is either battery charge maximization, link margin (equivalent to antenna gain) maximization, or experiment temperature minimization. All optimization problems consider reaction wheel angular velocity and reaction wheel angular acceleration constraints, and five of the optimization problems consider either battery charge constraints, antenna gain constraints, or both battery charge and antenna gain constraints. Reaction wheel constraints are satisfied using an attitude state filter at the output of the FISs and an optimal magnetic torque / reaction wheel desaturation algorithm, the design of both of which is presented herein. Optimal attitude state trajectory, or attitude profile, FISs are compared with a nominal attitude profile. It is shown that, while the nominal attitude profile offers good performance with respect to both battery charge and link margin, the optimal attitude profile FISs are able to outperform the nominal profile with respect to all objectives, and a minimum temperature attitude profile FIS is able to achieve average experiment temperatures 30–40 K lower than the nominal attitude profile. The attitude state trajectory optimization solutions presented in this work are motivated by the needs and constraints of the CryoCube-1 mission. Because this work is integral to the functionality of the CryoCube-1 satellite system, the effort taken to successfully build, test, deliver, launch, and deploy this CubeSat is detailed. The intent of providing this systems view is to provide the context necessary to understand exactly how the attitude state trajectory optimization results were used within the satellite system.

Committee: Kelly Cohen Ph.D. (Committee Chair); Manish Kumar Ph.D. (Committee Member); Ou Ma Ph.D. (Committee Member); Phil Putman Ph.D. (Committee Member); Anoop Sathyan Ph.D. (Committee Member) Subjects: Aerospace Materials

MS, University of Cincinnati, 2015, Engineering and Applied Science: Aerospace Engineering

UAVs are being increasingly used today than ever before in both military and civil applications. They are heavily preferred in “dull, dirty or dangerous” mission scenarios. Increasingly, UAVs of all kinds are being used in policing, fire-fighting, inspection of structures, pipelines etc. Recently, the FAA gave its permission for UAVs to be used on film sets for motion capture and high definition video recording. The rapid development in MEMS and actuator technology has made possible a plethora of UAVs that are suited for commercial applications in an increasingly cost effective manner. An emerging popular rotary wing UAV platform is the Quadrotor A Quadrotor is a helicopter with four rotors, that make it more stable; but more complex to model and control. Characteristics that provide a clear advantage over other fixed wing UAVs are VTOL and hovering capabilities as well as a greater maneuverability. It is also simple in construction and design compared to a scaled single rotorcraft. Flying such UAVs using a traditional radio Transmitter-Receiver setup can be a daunting task especially in high stress situations. In order to make such platforms widely applicable, a certain level of autonomy is imperative to the future of such UAVs. This thesis paper presents a methodology for the autonomous control of a Quadrotor UAV using Fuzzy Logic. Fuzzy logic control has been chosen over conventional control methods as it can deal effectively with highly nonlinear systems, allows for imprecise data and is extremely modular. Modularity and adaptability are the key cornerstones of FLC. The objective of this thesis is to present the steps of designing, building and simulating an intelligent flight control module for a Quadrotor UAV. In the course of this research effort, a Quadrotor UAV is indigenously developed utilizing the resources of an online open source project called Aeroquad. System design is comprehensively dealt with. A math model for the Quadrotor is developed and (open full item for complete abstract)

Committee: Kelly Cohen Ph.D. (Committee Chair); Elad Kivelevitch Ph.D. (Committee Member); Bruce Walker Sc.D. (Committee Member) Subjects: Aerospace Materials

Doctor of Philosophy (PhD), Ohio University, 2024, Communication Studies (Communication)

SIKAPOKOO, GRACE O., Ph.D., May 2024, Communication Studies Helping Black Breast Cancer Survivors Make Healthy Lifestyle Changes: How Family Communication Influences Progression Through the Stages of Change Director of Dissertation: Amy E. Chadwick In this dissertation, I set out to understand how family communication could influence and motivate behavior change for Black breast cancer survivors (BCSs) to improve their overall well-being and quality of life (QoL). Using the stages of change (SoC) model, the theory of planned behavior (TPB), and social support, I developed a model by integrating the SoC model with the TPB variables as a first layer on behavior change and take social support as a second layer to the model to hypothesize how family communication, through social support could help with the behavior change process for Black BCSs. To determine the role of family communication in behavior change, I conducted semi-structured interviews, which lasted between 45-75 minutes each on average. I interviewed 20 Black BCSs who had completed their breast cancer surgeries and treatment, had recovered, and were living in the United States. The interviews were conducted via video conferencing with automatically generated transcripts from Otter AI. The study found that family communication through social support can support Black BCSs to change their behaviors and improve their overall well-being and QoL. The study confirmed that family communication can positively influence TPB variables. As the variables change positively, they increase in behavioral intention alongside the progression of the stages of change, leading to the adoption of a new behavior. The study also found that social support received through family communication can help to progress people through the stages of change, to achieve behavior change. In addition, the study identified four domains for well-being that had had specific differences regarding the types of social support receive (open full item for complete abstract)

Committee: Amy Chadwick (Committee Chair); Angela Hosek (Committee Member); Lynn Harter (Committee Member); Anna Kerr (Committee Member) Subjects: Black Studies; Communication; Families and Family Life; Health

Doctor of Philosophy, The Ohio State University, 1974, Graduate School

Committee: Not Provided (Other) Subjects: Engineering

MS, University of Cincinnati, 2013, Engineering and Applied Science: Aerospace Engineering

The problem of magnetic attitude control of a CubeSat is analyzed. Three controller types are examined: a Constant-Gain Simple PD controller, a Linear Constant-Gain Optimal PD controller (i.e. an LQR), and a Fuzzy Gain-Scheduled PD controller. Each subsequent controller type utilizes a more-complex design algorithm. The Simple PD controller is tuned by hand iteration, the LQR is tuned using rule-of-thumb algorithms, and the Fuzzy Gain-Scheduled PD controller is designed using a Genetic Algorithm operating on two Fuzzy Inference Systems. Though the basic structures of these three controllers are identical, the differing design processes lead to different controller performance. The use of a Genetic-Fuzzy System is of particular interest, because this demonstrates the use of an intelligent algorithm to automate the controller design process. The techniques presented herein are directly applicable to any magnetically actuated satellite that can be modeled as a rigid body, although the mass distribution, geometry, and orbit of the satellite will determine controller-specific constants.

Committee: Kelly Cohen Ph.D. (Committee Chair); Elad Kivelevitch Ph.D. (Committee Member); Phil Putman Ph.D. (Committee Member); Grant Schaffner Ph.D. (Committee Member) Subjects: Aerospace Materials

Master of Science, University of Toledo, 2010, Mechanical Engineering

This CFD study investigates the effectiveness of transpiration channels for attitude control of a high-speed missile. The channel geometry is progressively adjusted based on the flow results from CFD studies to develop an optimized configuration. Additional sensitivity studies are conducted with the chosen best channel geometry on the effects of geometric parameters, Mach number, and angle-of-attack (AOA). In order to compare the control moments generated and the drag induced by the transpiration channels with the more commonly used spoiler, the Mach number and AOA CFD sensitivity studies are repeated on a generic spoiler geometry. The CFD study shows that the transpiration channels generate the control moments desired, but at a smaller magnitude and with much less drag than the spoilers. Once optimized, the performance of the transpiration channels is relatively insensitive to small changes in geometric parameters. The one exception is the channel cross sectional area, where the larger the channel cross-sectional area the larger the control moment produced. Lowering the Mach number and increasing the AOA both decrease the magnitude of the pitch moment produced, while yaw decreases and roll increases with increase in AOA. Similarly, the spoiler studies show decreased pitch moment with lower speed and increased AOA.

Committee: Terry Ng (Committee Chair); Sorin Cioc (Committee Member); Abdollah Afjeh (Committee Member) Subjects: Engineering; Fluid Dynamics; Mechanical Engineering

Master of Arts, The Ohio State University, 2010, Psychology

Perception, according to Bruner (1957), necessarily involves categorization. In deciding what something is, we have to attribute to it a given category that distinguishes it from anything outside of that category. Categorization, further, affects our evaluation of that object. A piece of cake categorized as a birthday gift will be evaluated more positively than a piece of cake categorized as a fatty food. The question here becomes how one can make one potential category more likely to dominate the categorization process. Previous research has demonstrated that attitude accessibility increases the likelihood of attending to a visual object (Roskos-Ewoldsen & Fazio, 1992) or a potential categorization (Smith, Fazio, & Cejka, 1996). The current research focuses on the use of attitude rehearsal to influence the use of one category (or one dimension, as in Experiment 2) over another in evaluating a related category member, and finds that categories (dimensions) towards which participants have accessible attitudes have more bearing on the evaluation of related target objects than categories (dimensions) which are less attitude-evoking.

Committee: Russell Fazio Ph.D. (Advisor); Kentaro Fujita Ph.D. (Committee Member); William Cunningham Ph.D. (Committee Member) Subjects: Psychology