Doctor of Philosophy, The Ohio State University, 2015, Electrical and Computer Engineering

The Dual Mechanical Port (DMP) electric machine has two rotors that can be set to rotate at different speeds and directions. Compared to conventional electric machines with only one rotor, the DMP machine provides higher torque density and much better control flexibility. However, the DMP machine has a relatively complex structure, which makes it a challenge to model and control. In addition, the existing model and control algorithms for single rotor machines cannot directly be applied to the DMP machine. In this study, it has been explore that how the DMP machine can be applied to hybrid electric vehicles as an avenue for explaining the electromagnetic characteristics and functionality of this more complex mechanism. The model and the control algorithms for two different DMP machines are also investigated. The first DMP machine, which is called the PMDMP, uses two layers of permanent magnets within the outer rotor. The second one, which is referred to as the SCDMP machine, uses a single layer of squirrel cage within the outer rotor, The study of the modeling and control for the SCDMP machine is the major contribution of this work. Compared to other DMP machines, the PMDMP machine stands out for its high torque density and high efficiency. A detailed model derivation for the PMDMP is presented later in the work. The independent control of its two rotors is investigated and verified by simulations and experiments. To overcome the problems brought about by the position sensors, the effectiveness of position sensorless control algorithms for the PMDMP is investigated. High frequency injection and sliding mode sensorless control algorithms are applied to the PMDMP machine at low speed and high speed, respectively. The performance of the sensorless control algorithms in experiments matches well with the simulation results. To verify the functionality of the DMP machine in power split hybrid application, the power flow pattern in various operational modes are discusse (open full item for complete abstract)

Committee: Longya Xu Dr. (Advisor); Jin Wang Dr. (Committee Member); Mahesh Illindala Dr. (Committee Member) Subjects: Electrical Engineering; Electromagnetics; Energy

Doctor of Philosophy, University of Akron, 2022, Electrical Engineering

This research proposes a direct voltage control approach for electric motors, including the single-stage converter topology and the control algorithms. The proposed motor drive system achieves smooth output voltage waveforms for phase excitations and utilizes them to extend the drive capability besides improving the torque ripple, noise, and vibration performance. Applicable to various motor types, the direct voltage control (DVC) is mainly investigated for driving switched reluctance motor (SRM) in the scope of this thesis. Different voltage regulation-based control algorithms are studied. Since the capability of shaping the phase voltage precisely allows control of any motor variables, this ability enables regulating the phase currents, flux linkages, and phase voltages to obtain superior performance. A finite element analysis (FEA) is performed to characterize the motor for building a dynamic simulation model for an SRM. The developed DVC and the conventional control are simulated using this machine model in comparison to each other. A new dual polarity power converter (DPC) is modeled, which can buck and boost the DC bus voltage and provides a variable voltage generation (VVG). The DPC can process power in both directions and provide a variable voltage in both positive and negative polarities at the motor windings. Following the DPC design process, power boards and gate driver boards are manufactured and populated as modular systems for individual motor phases. The developed converter model is customized and sized to construct a motor drive for the targeted operating conditions of the investigated SRM. It includes a control board to enable the 3-phase operation and a single DC bus as the power source for all three modular power converters. A resistive load setup is built to test the converter's performance. After verifying the DPC's performance for its designed load conditions and position-dependent dynamics, the motor tests are performed. The motor tests (open full item for complete abstract)

Committee: Yilmaz Sozer (Advisor); Patrick Wilber (Committee Member); Alper Buldum (Committee Member); Igor Tsukerman (Committee Member); J. Alexis De Abreu Garcia (Committee Member) Subjects: Aerospace Engineering; Alternative Energy; Electrical Engineering; Electromagnetics; Electromagnetism; Energy; Engineering; Technology

Master of Science, The Ohio State University, 2013, Electrical and Computer Engineering

The advances in power electronics devices have opened the possibility of counting on Synchronous Reluctance Motors (SRM) in applications where variations of speed are required. Evidently, for many years the Induction Motors (IM) have successfully supplied this demand, and they have become in undeniable leaders in the field. The strategy preferred to control both motors is based upon vector control, which allows them to operate in a wide range of speed. The necessity of having motors with low-cost and robust construction opened up to discussion and comparison between these two types of motors. In this study, a new approach based upon the Differential Evolution (DE) Algorithm was developed in order to design a 55Kw Induction Motor for variable speed applications, posteriorly, the performance of the final design was optimized by means of Finite Element Method (FEM) and evaluated through Indirect Field Oriented Current Control (IFOCC) strategy. Likewise, an equivalent Synchronous Reluctance Motor with inductance ratio in the range of 6-10 was also designed by using the same stator than the Induction Motor. A Vector Control (VC) strategy based upon the point of maximum power factor was implemented to test its performance. Initial sizing and torque density optimization of an Inverter-driven Induction Motor were performed by using a novel algorithm based upon the Differential Evolution paradigm, the resultant geometry demonstrated containing the transient and steady state responses desired. Finally, both motors optimized for variable speed applications were compared under the same variations of load, voltage and frequency in order to assess their consumption from an input apparent power point of view. By assuming a limit for the input power through the same Variable Frequency Driver (VFD), the Induction Motor was able to bear a higher overload, whereas the Synchronous Reluctance Motor compared favorably and showed lower power consumption in average under in (open full item for complete abstract)

Committee: Longya Xu (Advisor); Mahesh Illindala (Committee Member) Subjects: Electrical Engineering

Doctor of Philosophy, Case Western Reserve University, 2024, Applied Mathematics

Physiological systems underlying vital behaviors, such as breathing, walking, and feeding, are controlled by closed-loop systems integrating central neural circuitry, biomechanics, and sensory feedback. The brain and body orchestration allows these motor systems to demonstrate crucial biological phenomena such as homeostasis, adaptability, and robustness. In this thesis, we investigate the role of sensory feedback in motor dynamics and control, based on an abstract model for motor pattern generation that combines central pattern generator (CPG) dynamics with a sensory feedback mechanism. Given the underdevelopment of control theory for limit cycle systems, we extend recently developed variational tools, which allow us to characterize the sensitivity of the systems to perturbations and changing conditions both within and outside the body. As concrete examples, we apply our methods to several closed-loop models with sensory feedback in place, including locomotion, ingestion, and respiration. Our analytic framework provides a mathematically grounded numerical quantification of the effects of a sustained perturbation on the rhythm performance and robustness, which is also broad enough to study control of oscillations in any nonlinear dynamical systems. Moreover, the observations we obtain from the examples provide important information for future work modeling neuro-motor rhythm generation and insights that have the potential to inform the design of control or rehabilitation systems.

Committee: Peter Thomas (Advisor); David Gurarie (Committee Member); Erkki Somersalo (Committee Member); Hillel Chiel (Committee Member) Subjects: Applied Mathematics; Behavioral Sciences; Biology; Engineering; Mathematics; Neurosciences; Physiology

PhD, University of Cincinnati, 2022, Arts and Sciences: Psychology

After stroke, physical therapists must determine when an individual requires assistance (e.g., physical support) to complete a task and when an individual can execute a motor skill with less assistance. The decision about the amount of support to provide is often based on deviations of movement patterns from expected “norms.” In standing postural control, for instance, a therapist may provide steadying support with the intent to minimize postural fluctuations, even when support is not required to maintain standing balance. When therapists view deviations from norms as “incorrect” in individuals with stroke, they make an assumption that neurotypical individuals exemplify idealized movement patterns and that any variation from that comparator represents an error in performance. “Variability as error” is a pervasive clinical assumption, but it contrasts with the complexity science perspective that motor variability is not just randomness. Variability in motor performance is now understood as an expression of flexibility, allowing an individual to select a motor strategy to fit a given context. The purpose of this study was to determine the effect of physical therapist postural assistance during the practice of an upper-limb task on task performance and underlying motor control patterns in individuals with stroke. It was hypothesized that providing unnecessary assistance (postural stabilization) during practice would result in (a) faster improvements in task performance but (b) reduced immediate retention and more limited transfer; and (c) reduced task-sensitive postural control adjustments at transfer and following practice. Individuals with chronic stroke (n = 23) who were independent in standing balance participated. Participants stood on a force plate while immersed in a virtual scene displaying an anterior target. They aimed to position a virtual laser pointer (via handheld device) in the target. All participants then engaged in a practice period whe (open full item for complete abstract)

Committee: Michael Riley Ph.D. (Committee Member); Tehran Davis (Committee Member); Paula Silva Ph.D. (Committee Member) Subjects: Experiments

PhD, University of Cincinnati, 2020, Arts and Sciences: Psychology

When grasping and manipulating a hand-held object, the grip force (GF) a person applies has been typically reported as finely tuned to the object's load force (LF) as LF varies due to object accelerations, with GF adjustments exhibiting continuously synchronous and proportionate coordination with LF variations. Considering the existence of inherent sensorimotor feedback delays, synchronous GF-LF coordination thus indicates that GF anticipates future changes in LF. Prevailing theoretical accounts of GF control account for this anticipation via internal models that generate explicit predictions of future sensorimotor states on the basis of efference copies of outbound motor commands to enable feedforward (i.e., preprogrammed) anticipatory GF control. There are several theoretical issues with the internal model approach, however. In particular, it fails to properly acknowledge various computational limitations faced by the CNS. With regard to GF control, the internal model approach has not addressed the act of manipulating mechanically complex objects, which are objects that exhibit complex internal dynamics due to nonlinear, underactuated degrees of freedom. The pervasive ability for humans to skillfully manipulate complex objects raises a critical issue for the internal model approach as the underactuated, nonlinear dynamics of a complex object cannot be encoded by an efference copy, which makes internally modeling those dynamics unfeasible. An internal model account of GF control would therefore expect that GF would be unable to anticipate the changing LF exerted by a complex object as it is actively manipulated. However, other lines of research, such as the anticipatory synchronization framework, offer evidence that anticipatory control of complex dynamics can arise without needing to invoke internal model constructs. The current study aimed to critically test the internal model approach's pivotal claim—that efference copies of motor commands are essential to (open full item for complete abstract)

Committee: Michael Riley Ph.D. (Committee Chair); Tamara Lorenz Ph.D. (Committee Member); Paula Silva Ph.D. (Committee Member) Subjects: Psychology

Doctor of Philosophy, Case Western Reserve University, 2020, EECS - Electrical Engineering

A motor drive system implementing direct torque control (DTC) and a resonant link inverter to drive a permanent magnet synchronous motor (PMSM) is designed, built, tested, and analyzed, and performance is compared to a standard drive system using field oriented control (FOC) and a hard switching inverter (HSI). Models and simulations of both systems are developed and presented. Simulations and design, build, and testing of the selected resonant inverter topology, the active clamped resonant link inverter (ACRLI), are discussed. A description of the specification and buildup of the motor lab for this effort, including the motor controller implementation, the motor under test, the test load, and support equipment is also provided. DTC performance improvement efforts are discussed, including the implementation of multiple flux and torque estimation schemes. Experimental results on the research system, the DTC-ACRLI, studying the effects of inverter and controller parameters on performance, are discussed. Comparisons of two key system performance metrics (system efficiency and noise) between the baseline FOC-HSI system and the research DTC-ACRLI system are presented. Conclusions, contributions of the work, and suggested areas for future work are also discussed.

Committee: Kenneth Loparo Ph.D. (Committee Chair); Cenk Cavusoglu Ph.D. (Committee Member); Vira Chankong Ph.D. (Committee Member); Wei Lin Ph.D. (Committee Member) Subjects: Electrical Engineering

PhD, University of Cincinnati, 2020, Arts and Sciences: Psychology

Individuals who are skilled in a given motor task possess the ability to reliably achieve a desirable level of performance under variations in contextual conditions, even those not previously experienced. This ability is restricted in individuals with motor control impairments (MCI), whose functional performance in a variety of tasks is disturbed by contextual change. Previous research suggests that skilled individuals are resilient to contextual change not because they have discovered (with experience) generally effective task solutions but because they learned to leverage perceptual information in task space to swiftly adjust task solutions as conditions demand. Individuals with MCI seem to increase their attentional focus to the body and use a more deliberate, visually guided style of body control, which may restrict their ability to couple task solutions to circumstance. These findings support the central hypothesis of this dissertation: the impact of MCI on performance may depend on the extent to which individuals experiencing such impairment remain flexible and adapt task solutions to contextual change. To test this hypothesis, forty-five undergraduate students performed an object transportation task in virtual reality (VR). The task consists of using a virtual pad (controlled by hand movement) to move pucks across a bridge (extending forward) and into a container. Participants were free to choose their (global) task strategy: push the pucks and carefully position them inside the container, hit the puck from its initial position or any solutions in between (e.g., push the puck a particular distance before hitting). Participants performed the transportation task while standing on a force platform which provided a measure of their postural patterns used to describe their task solution at a lower scale of analysis. Sixty-five pucks were presented in each trial. Puck presentation rate was manipulated to vary contextual conditions. To induce the experience of reduc (open full item for complete abstract)

Committee: Anthony Chemero Ph.D. (Committee Chair); Paula Silva Ph.D. (Committee Chair); Tehran Davis Ph.D. (Committee Member) Subjects: Psychology

Doctor of Philosophy, University of Akron, 2018, Electrical Engineering

This dissertation addresses advanced control methodologies for the five-phase permanent magnet assisted synchronous reluctance motor (F-PMa-SynRM) drive under various open phase fault conditions. F-PMa-SynRMs are principally reluctance-type machines which contain fewer magnets than permanent magnet machines. The major advantage of F-PMa-SynRMs is their inherent fault-tolerant capability, which makes them suitable for critical applications in the automotive and aerospace industries. However, under different open phase faults, F-PMa-SynRMs lose their primary advantages due to reduced average torque and higher torque ripple creating severe vibrations that may cause immediate system shutdown. Additionally, the parameter estimation becomes challenging due to the temperature variations and the presence of current harmonics. In these situations, it is essential to develop advanced fault-tolerant control (FTC) methods for F-PMa-SynRMs targeting the maximization of average torque, minimization of torque ripple, and accurate estimation of temperature. Also, during the FTC, a fault detector is necessary to implement any feedback control methods. An optimal phase advance control method is proposed to maximize the reluctance torque with a minimum phase current under different open phase fault coniii ditions. Then, an active torque ripple minimization (TRM) technique adopting three major steps is proposed as follows: (i) active current harmonic identification, (ii) percentile harmonic injection, and (iii) vector rotation of healthy phases. After that, an analytical method is proposed to estimate magnet temperature in the F-PMa-SynRM without needing any temperature sensors. Finally, this dissertation develops a simplified fault detection method based on five-phase symmetrical component (SC) theory. Extensive simulation using MATLAB and finite element method is done to validate the theoretical claims. For further validation, experiments have been conducted on a 2.9 kW F-PMa-S (open full item for complete abstract)

Committee: Seungdeog Choi (Advisor) Subjects: Engineering

Doctor of Philosophy, The Ohio State University, 2017, Mechanical Engineering

With the fast development of batteries, sensors, and electric motors in the past decade, the ground vehicles are being increasingly electrified. With more sensors and actuators being equipped, they may suffer from increased possibility of sensor and actuator faults. This dissertation therefore addresses the fault estimation for sensors and actuators as well as fault-tolerant control for one type of electrified ground vehicle, i.e., the in-wheel motor electric vehicle. First, a prototype in-wheel motor electric vehicle is presented and the experimental platform is discussed. Then the problem of sensor fault estimation and reconstruction of contaminated signal is studied. Vehicle yaw rate signal is chosen as the contaminated signal and a robust gain-scheduling observer is proposed accordingly. Second, the steering motor fault estimation approach is developed because steering motor faults always impose a great threat to vehicle stability and safety. Furthermore, fault-type identification is also considered, which can provide detailed information of the type and magnitude of the actuator fault. Last, to deal with actuator fault and recover the faulty vehicle, an active fault-tolerant control system is proposed for in-wheel motor electric vehicles. It uses a baseline controller to accommodate actuator faults and stabilize the faulty vehicle when an actuator fault occurs. Actuator fault is detected and estimated by the fault detection and diagnosis mechanism. After that, a proper reconfigurable controller is switched on to recover the faulty vehicle. The proposed sensor and actuator fault estimation approaches and active fault-tolerant control system have been validated through simulations in CarSim® and/or vehicle experimental tests on an electric vehicle. At the end, future work and directions are given, which may further address the problems discussed in this dissertation.

Committee: Junmin Wang (Advisor); Ahmet Kahraman (Committee Member); Chia-Hsiang Menq (Committee Member); Yiying Wu (Other) Subjects: Engineering; Mechanical Engineering

Doctor of Philosophy, Case Western Reserve University, 2015, EECS - System and Control Engineering

A new class of algorithms for the identification and cancellation of harmonic disturbances on rotary dynamic systems is proposed and demonstrated with applications on the Green Bank Telescope (GBT). The approach is a model-based iterative algorithm that exploits the structure of the problem to significantly reduce the number of tests needed to perform identification. During each such test, the system is in steady-state periodic operation. The crucial trick involves constructing a correspondence between the coefficients of disturbance terms and their time-periodic harmonics. This transformation enables the modeling and calibration of the system in a compact, harmonic representation. This approach has numerous advantages. The harmonic model fully captures the behavior of arbitrarily complex linear systems. It is not a feedback approach and therefore will not destabilize existing controllers. The algorithm displays rapid convergence and requires a minimal number of tests to construct a model. Finally, a previously identified model may be reused to quickly update a calibration. All of these properties make it ideal for the calibration of feedforward compensators on a wide range of systems. The nature of cogging on the GBT motors is rigorously studied. Various system identification tests are performed to characterize the behavior of the cogging with respect to operating conditions. A single motor calibration routine is developed and deployed on telescope hardware. The performance of the GBT with individually calibrated motors is tested. Additionally, the algorithm is extended to handle multiple interacting motors. A solution method is presented that yields reliable, physically reasonable solutions to the multiple motor problem. The calibration method is updated to compensate for the GBT encoder measurement error. The behavior of interpolation error was studied on two different encoders. Global variation of encoder calibrations is studied over the r (open full item for complete abstract)

Committee: Mario Garcia-Sanz Dr. (Advisor); M. Cenk Cavusoglu Dr. (Committee Member); Vira Chankong Dr. (Committee Member); Roger Quinn Dr. (Committee Member) Subjects: Engineering

Doctor of Philosophy, The Ohio State University, 2011, Mechanical Engineering

This work studies spatial reaching motion in healthy humans. Research suggests that for individual instances of movement, the central nervous system (CNS) composes an explicit wrist path, which is transformed into joint motions in a time-invariant fashion. This is the time invariance hypothesis (TIH), and its validation for spatial motion is the first goal of this study. The human arm is typically modeled as a multi-link, serial chain. When one joint of a serial chain is actuated, it simultaneously causes movement at other joints because of interaction effects. Based on horizontal-plane reaching studies, the leading joint hypothesis (LJH) proposes that the interaction effects at (mostly) the proximal joint in the multi-link serial-chain model of the arm are low. Therefore, the CNS ignores this interaction effect to simplify the computation of joint torques and control of the joint trajectory. The second objective of this dissertation is to validate the LJH for spatial motion. In a spatial reaching experiment, healthy subjects performed point-to-point reaching movements at three distinct speeds. Data analysis revealed time-invariant wrist paths only for some subjects in some reaching tasks, suggesting that the TIH is not a truly general organizing principle for spatial reaching motion. Therefore, this hypothesis needs refinement and further investigation. On the other hand, the interaction effects at the shoulder joint were small for a majority of the movements in this experiment so, the LJH was successfully extended to spatial motion. The TIH identifies the inputs and outputs of the first stage in the process of composing the muscle activations for a given motor task. A computational algorithm that can potentially be used to execute this transformation was developed next. The algorithm, called speed-ratio control, also has beneficial applications in commercial robot control. It is demonstrated that the application of this algorithm to robotic serial chains provides (open full item for complete abstract)

Committee: James P. Schmiedeler Dr (Advisor); Gary L. Kinzel Dr (Advisor); Robert A. Siston Dr (Committee Member); Richard J. Jagacinski Dr (Committee Member) Subjects: Kinesiology; Mechanical Engineering; Robotics

Master of Science (MS), Ohio University, 2007, Electrical Engineering & Computer Science (Engineering and Technology)

This thesis presents an improvement in the performance of a three degrees of freedom differential thrust control testbed by considering the actuator dynamics. The testbed consists of three propellers that are used to produce thrust as well as attitude control for vertical takeoff and landing flight. Actuator dynamics consist of the motor-propeller dynamics and the nonlinear mapping relating the aerodynamic torques to the propeller speed. A previous controller was designed by neglecting the motor-propeller dynamics and the control allocation was done assuming a linear static relationship between aerodynamic torques and motor voltages. This work will determine the nonlinear control allocation mapping and model the motor-propeller dynamics as a first-order linear system. Simulation and real-time results showing an improvement in the performance of the testbed are presented by replacing the linear control allocation with nonlinear control allocation and by compensating for the motor-propeller dynamics. Further, the existing controller is redesigned considering the gyroscopic effects produced due to the spinning propellers.

Committee: Jianchao Zhu (Advisor) Subjects:

Master of Arts, Miami University, 2009, Psychology

Prospective control can be characterized as the ability to anticipate future events and act in an anticipatory manner to arrive at a desired goal. If this process is disturbed, one must actively explore the environment to properly detect new mappings. Virtual environments are able to circumvent the limitations of the physical environment and therefore can aid in determining the boundaries of people's ability to engage in prospective control. However, it has not been shown that the behaviors exhibited in these contexts are generalizable. Participants' head motion was recorded while they navigated through a physical or virtual maze. The results indicated main effects of time and segment as well as a time x segment interaction for both yaw and pitch rotations. There was no significant difference between the physical and virtual conditions nor were there any significant interactions involving condition. These changes reflect how behavior is modified to regain prospectivity.

Committee: L. James Smart PhD (Advisor); Robin D. Thomas PhD (Committee Member); David A. Waller PhD (Committee Member) Subjects: Psychology; Technology

Master of Arts, Miami University, 2007, Psychology

The general goal of this research was to describe how people maintain postural coordination under various constraints such as stress. In particular, the goal is to see how postural coordination changes when different types of stressors are employed. To accomplish this goal, participants were asked to balance on a beam while being exposed to a stressor. Both a cognitive stressor and a perceptual stressor were used. There were three levels of stress for each stress type. It was predicted that variability and range of postural motion would be constrained as stress levels increased and velocity of postural motion would increase with increased stress level. It was also predicted that participants would exhibit more random postural motion with increased stress levels. While many of the analyses failed to reveal significant differences among conditions, the results suggest a constraining of postural motion with higher stress levels. Results also showed a complex relationship between stress and performance for postural motion.

Committee: L. James Smart (Advisor) Subjects:

Doctor of Philosophy, Miami University, 2004, Psychology

Coordination of joints has not been well studied during quiet stance or non-locomotive suprapostural activity. This dissertation consists of three experiments examining multi-segmental postural coordination. Experiment 1, tested the effect of vision and support surface on multi-segmental postural kinematics and joint angles during upright quiet stance. Eight participants stood still on four surfaces (flat, foam surface, foam roller, wood beam) with eyes open and closed. Postural motion was recorded by an electromagnetic tracking device from the head, trunk, sacrum, hip, knee and ankle. Overall postural (head) sway and joint motion was influenced by both surface of support and vision. More sway and sagittal joint rotation occurred under non-visual and non-flat conditions. An ankle strategy as opposed to a hip strategy is primary in maintaining voluntary, upright balance on non-flat surfaces. In experiments 2 and 3, surface of support (hard surface vs. foam roller) and suprapostural task (head-tracking frequency) were manipulated simultaneously. Twelve different participants in each experiment stood on each surface with hands behind their back looking at a computer monitor in front of them. They were instructed to maintain balance while tracking a simulated oscillating (fore-aft) computer target with their head at different frequencies. In Experiment 2, a rest was given between trials (frequencies), whereas no rest was given between trials in Experiment 3. The effects of discrete (rest), and changing frequency modulation (no rest) on postural dynamics were then determined. Results demonstrate that people use a continuum of coordination strategies to accomplish head-tracking at different frequencies. On both surfaces, a predominantly anti-phase, hip-ankle relationship was seen with only gradual postural transitions observed. Dynamic standing tasks exhibit many similarities in postural coordination whether performed at a singular frequency or by modulating frequency. Ho (open full item for complete abstract)

Committee: Leonard Smart (Advisor) Subjects:

Doctor of Philosophy, Case Western Reserve University, 2025, Biomedical Engineering

This dissertation focuses on non-perceptual effects of artificial sensation measured by effects in the motor system. Tactile feedback is used throughout the brain, from the “highest” cortical level to the “lower” spinal or brain stem level. Touch is first used before perception, or pre-perceptually, by the brain stem in simple, automatic modulation of the motor system. For example, carrying an object from place to place or even shifting it in one's hand involves many changing tactile signals. Even a single ridge of a fingertip supplies a unique signal for use in object manipulation. If one had to actively perceive and act upon all this information, merely picking up an object would become overwhelming. Fortunately, the lower levels of our brain automatically make minor adjustments to grip based on tactile information. What is not known is how relevant perceptual qualities are to these automatic corrections to grip. The cortex, not the brainstem, is the location of tactile perception, so it stands to reason that the brainstem does not require “natural” qualities of tactile feedback. Our lab has a group of participants with peripheral nerve cuff electrodes we can stimulation through. We tested how well artificial tactile feedback would integrate with the sensorimotor system in tasks of increasing complexity. We found that peripheral nerve stimulation is processed similarly to naturally generated touch with and without perception and may engage with the motor system as seen by the intent to modulate grip force.

Committee: Dustin Tyler (Advisor); A Bolu Ajiboye (Committee Chair); Hillel Chiel (Committee Member); M. Cenk Çavuşoğlu (Committee Member) Subjects: Biomedical Engineering; Engineering; Neurosciences

Master of Science (M.S.), University of Dayton, 2024, Mechanical Engineering

The average physical therapy clinic lacks the funding and resources to install highly specific movement assessment and rehabilitation tools. Moreover, engagement of patients during rehabilitation is difficult to maintain due to the mundane nature of the routines. Virtual Reality (VR) systems have the capacity to become an all-in-one system that gives an engaging and highly customizable experience for each user. VR also incorporates wearable sensors that allow for tracking the position and orientation of individual segments. This study has two primary aims, the first is to validate that a VR system is capable of upper extremity movement motion capture comparable to the golden standard of infrared motion capture. The second aim is to assess movement task data extracted from a VR game to see if quantification of a cohort with spinal cord injury (SCI) is possible through a simulated task. Two cohorts were included in this study, a group of persons with history of SCI (n=7), and a control group (n=9). Each participant was asked to play a modified commercially available VR game known as BeatSaber. The levels were separated into therapy-based mirrored, opposing, and unilateral tasks. Moreover, each task was defined by its position and orientation relative to the user. Additionally, task color was used to distinguish which hand to perform the task with. Results from the VR system compared to the IR system showed that the overall error between the two systems was on average between 4.2°-8.6° and showed small instantaneous errors with all joint angles being less than 2°. Moreover, the instantaneous error was even lower at peak values reported in the IR system. Results allowed for a comparison of performance data for a combination of seven SCI with seven age and gender matched control groups. Task related data showed that SCI tended to have asymmetrical impact from injury and performed worse compared to the control group.

Committee: Allison Kinney (Advisor); Megan Reissman (Advisor) Subjects: Biomechanics; Biomedical Engineering; Biomedical Research; Mechanical Engineering; Rehabilitation

PhD, University of Cincinnati, 2024, Medicine: Neuroscience/Medical Science Scholars Interdisciplinary

Sports-related brain injuries, including both sports-related concussions (SRCs) and repetitive head impacts (RHI), are forms of brain injury that result from a direct hit to the head or biomechanical forces that are transmitted from the body to the head. It is estimated that 1.6 to 3.8 million SRCs occur annually with approximately 1.9 million occurring annually in adolescent athletes. With previous research focused on the management of neurocognitive and neurobehavioral symptoms following SRC, neuromuscular control deficits are also present in athletes following concussion. Neuromuscular control alterations have been noted up to two years following initial injury, potentially placing athletes at an increased risk for lower extremity injury following clearance of return to play. Additionally, athletes with a prior history of SRC have demonstrated a ~2.5 times greater risk for subsequent lower extremity injury compared to uninjured controls. Behavioral data has provided initial insight into the relationship between SRC and lower extremity injury, however, changes in the central nervous system (CNS) underlying this relationship have not been fully realized. Characterizing neural alterations associated with motor control may provide further insight as to why athletes with a history of SRC display neuromuscular deficits. Additionally, there is an unclear understanding of how RHI exposure may precipitate to the development of motor control deficits. Unlike athletes with an SRC, the absence of overt clinical symptoms, behavioral changes, or neurocognitive manifestations may lead to this population being overlooked. To characterize how sports-related brain injuries may lead to motor control deficits, a literature review is warranted to present the current evidence as it relates to sport-related head injuries, and subsequent lower extremity injury. The literature synthesis (Chapter 1) will provide a comprehensive overview of SRC, RHIs, and previous work that has identified (open full item for complete abstract)

Committee: Mark Baccei Ph.D. (Committee Chair); Jed Diekfuss Ph.D. (Committee Member); Michael Riley Ph.D. (Committee Member); Gregory Myer (Committee Member); Weihong Yuan Ph.D. (Committee Member); Russell Gore M.D. (Committee Member) Subjects: Neurosciences

Master of Science, The Ohio State University, 2023, Electrical and Computer Engineering

In this study, a user-friendly graphical user interface (GUI) was designed for the NeXUS Laser system, a state-of-the-art experimental setup comprising multiple beamlines, vacuum chambers, and end-stations. The GUI seamlessly integrated controls for motors, shutters, and cameras, facilitating their use during scientific experiments. Moreover, it provided real-time results, enabling users to process data concurrently. The development was underpinned by a comprehensive suite of libraries and frameworks in Python, complemented by the robust cross-platform capabilities of the QT framework. The study introduced a primary control panel concerning experimental processing, which was interconnected with both the motor control panel and the camera control panel. Notably, the emphasis was placed on refining a scanning mode for the experiment. To reduce execution time, concurrency was necessary for the program, transforming its execution in sequential to parallel. In this study, the multithreading technique was successfully incorporated into the scanning mode of the experiment. The results indicated that the use of multithreading effectively reduced the execution time of the scanning mode by 66%.

Committee: Xiaorui Wang (Advisor); Lisa Fiorentini (Committee Member) Subjects: Electrical Engineering