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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Towards A Mobile Damping Robot For Vibration Reduction of Power Lines

Kakou, Paul-Camille 18 May 2021 (has links)
As power demand across communities increases, focus has been given to the maintenance of power lines against harsh environments such as wind-induced vibration (WIV). Currently, Inspection robots are used for maintenance efforts while fixed tuned mass dampers (FTMDs) are used to prevent structural damages. However, both solutions are facing many challenges. Inspection robots are limited by their size and considerable power demand, while FTMDs are narrowband and unable to adapt to changing wind characteristics, and thus are unable to reposition themselves at the antinodes of the vibrating loop. In view of these shortcomings, we propose a mobile damping robot (MDR) that integrates inspection robots' mobility and FTMDs WIV vibration control to help maintain power lines. In this effort, we model the conductor and the MDR by using Hamilton's principle and we consider the two-way nonlinear interaction between the MDR and the cable. The MDR is driven by a Proportional-Derivative controller to the optimal vibration location (i.e, antinodes) as the wind characteristics vary. The numerical simulations suggest that the MDR outperforms FTMDs for vibration mitigation. Furthermore, the key parameters that influence the performance of the MDR are identified through a parametric study. The findings could set up a platform to design a prototype and experimentally evaluate the performance of the MDR. / Master of Science / Power lines are civil structures that span more than 160000 miles across the United States. They help electrify businesses, factories and homes. However, power lines are subject to harsh environments with strong winds, which can cause Aeolian vibration. Vibration in this context corresponds to the oscillation of power lines in response to the wind. Aeolian vibration can cause significant structural damages that impact public safety and result in a significant economic loss. Today, different solutions have been explored to limit the damages to these key structures. For example, the lines are commonly inspected by foot patrol, helicopters, or inspection robots. These inspection techniques are labor intensive and expensive. Furthermore, Stockbridge dampers, mechanical vibration devices, can be used to reduce the vibration of the power line. However, Stockbridge dampers can get stuck at location called nodes, where they have zero efficiency. To tackle this issue, we propose a mobile damping robot that can re-adjust itself to points of maximum vibration to maximize vibration reduction. In this thesis, we explore the potential of this proposed solution and draw some conclusions of the numerical simulations.
2

Simultaneous Vibration Control and Energy Harvesting of Nonlinear Systems Applied to Power Lines

Kakou, Paul-Camille 28 May 2024 (has links)
The resilience of power infrastructure against environmental challenges, particularly wind-induced vibrations, is crucial for ensuring the reliability and longevity of overhead power lines. This dissertation extends the development of the Mobile Damping Robot (MDR) as a novel solution for mitigating wind-induced vibrations through adaptive repositioning and energy harvesting capabilities. Through comprehensive experimental and numerical analyses, the research delineates the design, optimization, and application of the MDR, encompassing its dynamic adaptability and energy harvesting potential in response to varying wind conditions. The study begins with the development and validation of a linearized model for the MDR, transitioning to advanced nonlinear models that more accurately depict the complex interactions between the robot, cable system, and environmental forces. A global stability analysis provides crucial insights into the operational limits and safety parameters of the system. Further, the research explores a multi-degree-of-freedom system model to evaluate the MDR's efficacy in real-world scenarios, emphasizing its energy harvesting efficiency and potential for sustainable operation. Findings from this research show the clear promise for the development of the MDR with the consideration of the nonlinear dynamics in play between the robot, the cable, and the wind. This work lays a foundational framework for future innovations in infrastructure maintenance, paving the way for the practical implementation of mobile damping technologies in energy systems. / Doctor of Philosophy / Across the United States, over 160,000 miles of power lines crisscross the landscape, powering everything from small homes to large industrial complexes. These critical infrastructures, however, are constantly battered by the elements, particularly by strong winds capable of inducing Aeolian vibrations. Such vibrations lead to oscillations in the power lines due to wind forces, potentially causing severe structural damage, compromising public safety, and incurring considerable economic costs. In response to these challenges, various mitigation strategies have been employed. Traditional methods include regular inspections carried out by foot patrols, helicopters, or sophisticated inspection robots, though these approaches are notably resource-intensive and costly. Additionally, mechanical devices like Stockbridge dampers are utilized to dampen the vibrations, but they suffer from efficiency issues when misaligned with the vibration nodes. This dissertation extends the study to an innovative solution to overcome these limitations: a mobile damping robot designed to navigate along power lines and autonomously position itself at the points of highest vibration amplitude, thereby optimizing vibration dampening. This study delves into the feasibility and effectiveness of such a solution, supported by thorough numerical simulations. The aim is to demonstrate how this advanced approach could redefine maintenance strategies for power lines, enhancing their resilience against wind-induced vibrations and reducing the reliance on laborious inspection methods and static damping devices with limited efficiency.

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