This dissertation demonstrates that a magnetic-levitation (maglev) stage has the capabilities to control movements and reject vibration simultaneously. The mathematical model and vibration control scheme with a 6-degree-of-freedom (6-DOF) maglev stage for nanoscale positioning are developed for disturbance rejection. The derived full nonlinear dynamic equation of motions (EOMs) of the maglev stage include translational and rotational motions with differential kinematics. The derived EOMs and the magnetic forces are linearized to design a multivariable controller, a Linear Quadratic Gaussian with Loop Transfer Recovery (LQG/LTR), for vibration disturbance rejection in a multi-input multi-output (MIMO) system. For a more accurate model, the dynamics of an optical table with a pneumatic passive isolation system is also considered. The model of the maglev stage with the optical table is validated by experiments. Dual-loop controllers are designed to minimize the influence of the vibration disturbance between the moving platen and the optical table in the x-, y-, and z-axes motions. The inner-loop compensator regulates the velocity to reject vibration disturbance and the outer-loop compensator tracks positioning commands. When the vibration disturbances of 10 to 100 Hz are applied, the vibration-reduction ratios are about 30 to 65 percent in horizontal motion and 20 to 45 percent in vertical motion. In addition, the vibration disturbances of 45.45 Hz are attenuated by about 4 to 40 percent in angular motions. The vibration control schemes are effective in not only translational but rotational motions. In step responses, the vibration control schemes reduce the wandering range in the travel from the origin to another location. Positioning and tracking accuracies with the vibration controller are better than those without the vibration controller. In summary, these dual-loop control schemes with velocity feedback control improved the nanopositioning and vibration/disturbance rejection capabilities of a maglev system.

This dissertation is the first attempt to demonstrate the use of magnetic-levitation (maglev) positioners for commercial applications requiring nanopositioning. The key objectives of this research were to devise the control strategies and motion planning to overcome the inherent technical challenges of the maglev systems, and test them on the developed maglev systems to demonstrate their capabilities as the next-generation nanopositioners. Two maglev positioners based on novel actuation schemes and capable of generating all the six-axis motions with a single levitated platen were used in this research. These light-weight single-moving platens have very simple and compact structures, which give them an edge over most of the prevailing nanopositioning technologies and allow them to be used as a cluster tool for a variety of applications. The six-axis motion is generated using minimum number of actuators and sensors. The two positioners operate with a repeatable position resolution of better than 3 nm at the control bandwidth of 110 Hz. In particular, the Y-stage has extended travel range of 5 mm × 5 mm. They can carry a payload of as much as 0.3 kg and retain the regulated position under abruptly and continuously varying load conditions. This research comprised analytical design and development, followed by experimental verification and validation. Preliminary analysis and testing included open-loop stabilization and rigorous set-point change and load-change testing to demonstrate the precision-positioning and load-carrying capabilities of the maglev positioners. Decentralized single-input-single-output (SISO) proportional-integral-derivative (PID) control was designed for this analysis. The effect of actuator nonlinearities were reduced through actuator characterization and nonlinear feedback linearization to allow consistent performance over the large travel range. Closed-loop system identification and order-reduction algorithm were developed in order to analyze and model the plant behavior accurately, and to reduce the effect of unmodeled plant dynamics and inaccuracies in the assembly. Coupling among the axes and subsequent undesired motions and crosstalk of disturbances was reduced by employing multivariable optimal linear-quadratic regulator (LQR). Finally, application-specific nanoscale path planning strategies and multiscale control were devised to meet the specified conflicting time-domain performance specifications. All the developed methodologies and algorithms were implemented, individually as well as collectively, for experimental verification. Some of these applications included nanoscale lithography, patterning, fabrication, manipulation, and scanning. With the developed control strategies and motion planning techniques, the two maglev positioners are ready to be used for the targeted applications.

This dissertation reports the investigation conducted on the static and dynamic behavior of the passive diamagnetic levitation systems. Attachment of a device to a substrate hinders the optimum performance ability of vibrating devices by altering the dynamic behavior of the moving part whilst introducing higher overall stiffness. The significance of this effect is prominent especially in vibration based energy harvesters as higher stiffness elevates the resonance frequency of the system, making it difficult to tune into ambient low frequencies. Other advantages of the proposed method are given by the removal of mechanical bending elements, which are often the source of energy dissipation through thermo-elastic damping and affects device reliability and durability. In this research, diamagnetically levitated resonators that can be utilized in energy harvesting were proposed and investigated as a possible solution to overcome these problems. Permanent magnets in an opposite neighboring poles (ONP) configuration were used to provide the magnetic field required for levitation. Pyrolytic graphite (PG), which is the known highest diamagnetic material, serves as the levitating proof mass. Experimental results show that the static levitation height has a linear dependence on the thickness and a nonlinear dependence on the area of the levitating proof mass that can be approximated to a third order polynomial equation. Also, the study proved that a thinner proof mass provides a higher air gap while length of the proof mass beyond a certain value (l >10 mm for the experimental system considered in this dissertation) has no significant effect on increasing the air gap. It was also observed that levitation can slightly increase by attaching magnets to a sheet of steel (ferromagnetic material). To the best of my knowledge, this dissertation is the first to address the parameterized studies in the dynamics of diamagnetic levitated objects by permanent magnets. Measurements performed on a diamagnetic levitating prototype system show that the resonance frequencies are lowered by approximately 3- 4 orders of magnitude in levitated systems compared to the attached systems demonstrating the feasibility of using levitating techniques for micro to meso scale energy harvester applications. Also, there is a significant dissimilarity observed in this study compared to the mechanically attached systems: The resonance frequency has a dependence on magnetic field strength, and is shifting towards lower values when increasing the strength of the magnetic field. This indicates that the virtual spring of a levitated proof mass is not a constant and therefore, the resonance frequency of the diamagnetic levitated systems is able to be fine-tuned by varying the magnetic field. Finite Element Method (FEM) models were developed using COMSOL software that can simulate 3D magnetic flux formation of an array of permanent magnets and the diamagnetic levitation. The appropriate magnetic force equation from the two force equations that exist in the literature was established for the static levitation with the help of experimental and simulation results. Moreover, these models are able to provide the magnetic force exerted on diamagnetic objects at different heights, stable levitation height and position and also an indication of the maximum stably levitated size of the diamagnetic material. Future endeavor of this study is to realize the diamagnetic levitation in energy harvesters. The results obtained from this research will not be limited to harvester applications but will also be beneficial to other diamagnetic levitation related systems, as these parameters are fundamental and necessary for the foundation of the research in the field of interest.

The implementation of high-speed passenger trains (HST) within existing highway right-of-way (ROW) offers a solution for regions with a demand for the capacity and service offered by HST but lacking the support for sharing freight rail ROW or acquiring new ROW corridors. The states of Florida, Colorado, California and Nevada propose to use highway ROW for their HST projects to increase the capacity of the corridor, prevent or minimize impacts and prevent disruption of freight rail operations. Despite the constraints of using existing highway ROW, such as speed-limiting degrees of curvature and safety concerns, solutions and mitigation measures exist. The purpose of this thesis is to present the HST projects in the United States proposing use of highway ROW, the potential benefits and engineering issues to consider and the feasibility of using the existing I-35 ROW in Texas for HST. / text

<p>High precision magnetic levitation control methodologies during the manufacture of Organic light-emitting diode (OLED) displays are designed, manipulated, and experimentally validated in this thesis. OLED displays have many advantages over conventional display technologies including thinner, lighter, lower power consumption, higher resolutions, and greater brightness. However, OLED displays require tighter environmental conditions of the manufacturing processes without the introduction of vibration and contamination. For this reason, magnetic levitation is used to transport the displays attached on the carrier during the manufacturing process. This thesis addresses several critical problems related to implement the levitation control performance of the carrier's motion during the manufacturing process. </p> <p>Attractive magnetic levitation requires measurement of the airgap between the carrier and the levitation electromagnets. An algorithm for modeling the gap sensor installation errors was developed and subsequently used for controller development. A levitation controller only was initiated as the stationary point for optimal state feedback controller-observer compensator developed in this study. This optimal state feedback controller-observer compensator allows the carrier to be passed from support fixtures without the introduction of vibration. This controller was designed, and its levitation control performance confirmed with both simulation and experimental validation. To implement the levitation control performance of the carrier's motion, a second order notch filter and a first order low pass filter are designed to minimize the mechanical resonance and noise from the gap sensor, respectively. To reduce the sudden change of the levitation forces owing to the discrete allocation of the levitation electromagnets, a section control algorithm is developed; the sum of the levitation forces is equal to the weight of the carrier and the sum of the moment along the propulsion axis is equal to zero. </p> <p>Using the developed control strategies, the peak to peak variation of the carrier’s motion at a standstill was 50 µm. This same motion at low-speed 30 mm/s was 250 µm. While at high speed 300 mm/s was 430 µm. The relative improvement in the levitation control performance of optimal state feedback controller-observer compensator over the levitation controller only was a peak to peak attenuation of 50 µm at low-speed and 270 µm at high-speed. Most significantly while using optimal state feedback controller-observer compensator could be passed from support fixture to support fixture, i.e., through the deadzone, without mechanical contact or other manufacturing processes, inhibiting vibration. </p> <p>Having comparative simulation and experimental validation, the proposed control strategies were validated to improve the levitation control performance of the carrier under uncertain disturbance and sensor installation error, and it is expected to manufacture OLED displays with high productivity and low defect rate.</p>

The project originated with the question "What is the future of urban mobility?" and the counterquestion "What is the future of urbanity?". To understand the future of mobility, we first need to try to understand more of the future context where it'll reside. Mobility and the context it exists within are two symbiotic yet constantly evolving elements. This project seeks to speculate about their respective state in the year of 2050. Our global population keeps on growing, and more people are moving into urbanized regions. Already today more 90% of the worlds population is concentrated on roughly 10% of our planets land surface, and the density keeps increasing. To cope with the expanding population, cities need to keep growing and create sustainable infrastructure. The trend in densely populated regions has been to grow in the vertical axis. Besides just residential spaces, modern cities are starting to distribute shops, utilities and other typical city content vertically as well. City blocks and their content that used to be spread out in the horizontal plane are now increasingly being housed within compact hubs over multiple levels vertically. This project proposes the idea of a prototype sub-city within a mega city in the South East Asian region, around the year of 2050. Created as a way to prototype solutions to challenges found in hyper densely populated regions ranging from urban planning and congestion to general liveability. The fictional district has a highly vertically oriented cityscape, consisting of many interconnected highrises and megastructures. Traversing the walls of the buildings, vertically and horizontally, are vehicles propelled through magnetic levitation technology on an inductive infrastructure retrofitted onto or built into the buildings in the region. The far future, visionary setting of the project intends to provoke thoughts and reflection about an urban lifestyle within a far more vertically oriented environment. The thesis also aims to paint a picture of a car free city hub where vehicles are bound to the vertical plane, and the horizontal plane is devoted to the community of the city. Whether it's on the ground level or multiple stories up in a luscious "sky garden", the horizontal planes belong to the people and are roamed by foot. The process behind the development of the project involved research into the future setting and emerging technologies. Creative development and ideation were done using analogue as well as digital sketching, brainstorm sessions and physical and digital mockuping. The final vizualisations and compositions were designed from storyboards describing typical use cases of the vehicle. After researching topics of future cityscapes, creating the future premise of the project and ideating and refining various ideas, the end result of the thesis is Vertal Hex. A maglev propelled shuttle targetting future businesses. Travelling along the walls of the interconnected megastructures making up the future cityscape and company campuses, it allows it's passengers to reach their destinations anywhere within the hub entering right at the floor of their destination.

The project is highly inspired by the rise of vertical cityscape and how it can shape a new context for mobility to exist within. When the destinations travelled will be spread out in the vertical landscape instead of only the horizontal one. A rearrangement of housing, schools, restaurants and parks will create new needs for mobility to fill. In which the vehicles restricted to the two dimensional format of today can not. This will create a new era of vertical transportation to combat the densification of the future. The project investigates how new technologies such as magnetic levitation could be applied to architecture and open up space for vertical transportation. To give a flexible mobility system in high rise, high density urban areas. And with this create walkways thriving with nature on the horizontal planes. That promotes walkability, social connections and gives more space to people. For this to work, the project was set in the year of 2050 inside of a protoype district. By the reason to let the technology mature, this will also be a pivotal time of how to accommodate for the densification. Exploring how mobility would work and the everdaylives of the innhabitants in the district. The Project aims to provoke the perception of what a future urban area could be and how it would affect the need for transportation. When the premise was set, the mission was to create this new type of mobility, its functionality, its experience and of course a vehicle to convey these different elements. This was made through a number of ideation sessions, physical prototypes, hand sketches, digital sketches and digital modeling. Realizing it into an viable solution. The result of this project is Vertal Mono, A compact vehicle suited for the era of vertical transportation. It is designed to be a daily commuting vehicle within Vertico district, a prototype district testing vertically connected cityscapes. Mono is designed to be the smaller human footprint pod of the Vertal line up. It is nimble and flexible, being able to reach anywhere at any time. It is an essential part of mobility to the inner circles of the district and part of the communities living there. Vertal offers an on demand shared experience whether the occupant is riding for a single minute or for 15. The interior space offers great flexibility as a response to the vast range of usecases it needs to fulfill.

The magnetic field analysis based on the wavelet transform is performed. The Halbach array magnetic field analysis has been studied using many methods such as magnetic scalar potential, magnetic vector potential, Fourier analysis and Finite Element Methods. But these analyses cannot identify a transient oscillation at the beginning stage of levitation. The wavelet transform is used for analyzing the transient oscillatory response of an EDS Maglev system. The proposed scheme explains the under-damped dynamics that results from the cradle's dynamic response to the irregular distribution of the magnetic field. It suggests this EDS Maglev system that responds to a vertical repulsive force could be subject to such instability at the beginning stage of a low levitation height. The proposed method is useful in analyzing instabilities at the beginning stage of levitation height. A controller for the EDS maglev system with the Halbach array magnet is designed for the beginning stage of levitation and after reaching the defined levitation height. To design a controller for the EDS system, two different stages are suggested. Before the object reaches a stable position and after it has reached a stable position. A stable position can be referred to as a nominal height. The former is the stage I and the latter is the stage II. At the stage I, to achieve a nominal height the robust controller is investigated. At the stage II, both translational and rotational motions are considered for the control design. To maintain system stability, damping control as well as LQR control are performed. The proposed method is helpful to understand system dynamics and achieve system stability.

The objective of this study is to set a methodology for the economic evaluation of high speed ground transportation systems. The main objective of this study is to establish a systematic framework, in order that planners can quickly understand and analyze the implications that different policies have on the life-cycle of the transportation system. The methodology is adaptable for different modes and also for different locations at which similar systems could be implemented. The mode under consideration here is that of Magnetically levitated vehicles and the study area is the Northeast corridor of the United States. The economic evaluation is based on a Systems Dynamics simulation model. The model incorporates socioeconomic parameters, trip generation, mode split, traffic engineering, economic parameters and elements of mass transportation. The interactions within these subsystems and between them are studied through various policy analysis which were conducted. The range of policy covers socioeconomic parameters, traffic strategies and economic parameters. Life cycle costs and revenues are the key performance indicators. Parameters such as elasticity values were assumed based on previous studies conducted in other locations. Revenues from fares is the only benefit considered for implementation of the new transportation system. The model has been developed so that it can be expanded so as to include various other benefits from maglev implementation. The model is highly flexible and can be used for a wide range of policy analysis. With regard to magnetic levitated transportation system it was found to be an economically feasible transportation alternative to solve the problems facing high speed inter-city travel. The life cycle costs of such a venture were found to be highly sensitive to the cost of power and the elasticity values associated with the trip generation model. / Master of Science

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