IN-WHEEL COUPLED SUSPENISON AND DRIVE SYSTEM FOR ATTITUDE CONTROL AND VEHICLE PROPULSION

The automotive marketplace is a volatile and dynamic system driven by consumer desires, marketing, fuel prices, technology, and legislation. Recently many of these factors have culminated in a common effort to encourage hybrid and electric vehicle development. The technology for electric vehicles has finally found enough maturity to be implemented into consumer based vehicles from hybrid SUVs to high performance sports cars. This expansion in available propulsion systems and vehicle architectures has spurred research and development into new and novel approaches for propulsion as well as systems to provide increased ride comfort. This work presents a dual electric motor drive system that incorporates a mechanism that allows not only longitudinal actuation of the vehicle, but also low frequency vertical actuation of the vehicle. The system is able to achieve this by coupling two motors per wheel and combining them with a new kinematic mechanism that facilitates dual degree of freedom actuation with coupled motors. By utilizing two motors coupled together to actuate the two degrees of freedom, more efficient utilization of resources is possible. Rather than having a motor that provides longitudinal motion and another that provides vertical actuation, the system uses two motors coupled together to provide both. When one degree of freedom doesn\u27t require actuation, the motors can be utilized to provide higher performance in the other degree of freedom. This system is designed, modeled, and actually converted into a prototype design throughout the entirety of this work. Initial conceptual modeling and performance metric definition occurs in a kinematic analysis of a basic mechanism. This is then developed into a more complex three dimensional model, and finally converted into physical hardware. In parallel to the hardware development, the controller that allows the system to operate is also explored. From actuating a single degree of freedom to a linearized coupling algorithm that allows both degrees of freedom to be controlled independently and simultaneously, the control system evolves into a functioning system

Bracket formalism applied to phase field models of alloy solidification

We present a method for coupling current phase field models of alloy solidification into general continuum modelling. The advantages of this approach are to provide a generic framework for phase field modelling, give a natural and thermodynamically consistent extension to non-isothermal modelling, and to see phase field models in a wider context. The bracket approach, introduced by Beris and Edwards, is an extension of the Poisson bracket of Hamiltonian mechanics to include dissipative phenomena. This paper demonstrates the working of this formalism for a variety of alloy solidification models including multi phase, multi species with thermal and density dependency. We present new models by deriving temperature equations for single and more general phase field models, and postulate a density dependent formulation which couples phase field to flow

A unified framework for hybrid control : b background, model, and theory

Caption title. "April 1994: Revised June 1994."Includes bibliographical references (p. 24-25).Supported by the Army Research Office and the Center for Intelligent Control Systems. DAAL03-92-G-0164 DAAL03-92-G-0115Michael S. Branicky, Vivek S. Borkar, Sanjoy K. Mitter

Investigation of Tribochemical Reactions Using the Model System of Methyl Thiolate on Copper Foil in Ultrahigh Vacuum and Ab-Initio Calculations

Advancement in the understanding of tribochemical systems suffers from several obstacles that hinder the progress in advancing an understanding of the fundamental processes involved in the evolution of friction and wear. Characterizing ephemeral chemical states within a buried interface is an experimental challenge and work in this dissertation uses a model system, methyl thiolate on copper foil, that undergoes tribo-activated decomposition to investigate the rate of change of the chemical components in the interface. The elementary steps in the tribochemical reaction were identified and consist of a shear-induced decomposition of methyl thiolate species to produce gas-phase hydrocarbons and form surface sulfur, which is mechanochemically transported into the sub-surface copper region resulting in changes in the friction coefficient. A method has been developed to analyze the changes in sliding-induced gas-phase product formation and friction coefficient as a function of the number of passes over the surface with a tribopin. Finally, the Vienna Ab-Initio Simulation Package (VASP) is used to calculate the methyl thiolate decomposition energies on Cu(100) as a function of load and the results are compared to the extended-Bell model

Formalization and Visualization of an Automatic Production Line

Verification and Validation (V&Y) of control software is nowadays assuming great significance in manufacturing systems, for it has been finally understood that a thorough study on this subject could mean a considerable improvement in the efficiency of production processes. For this reason V&V has become a necessity due to the pressures of market demand. Manufacturing companies tend to solve these market pressures by the use of testing. But it is not quite correct, due to the fact that testing is a heuristic methodology and it has not a scientific foundation. This thesis proposes another different methodology –a method consisting in the abstraction of the controlled object in a formal representation, –better known as "formalization". By means of formalization much more system information can be obtained and be used in the improvement of the efficiency of production processes. In this thesis the benefits of formalization are proven by the application of the methodology in a real case. It means that the formalization of a case study will be developed obtaining significant results that will prove their own benefits. After the formalization the system can be subjected to model-checking –where a lot of information can be extracted from. One of the results of this thesis is the obtaining of the state space and the timing diagram of the system. Furthermore in this thesis it is highlighted and exposed one of the possible applications of formal methods –the system simulation in a visual representation

Doctor of Philosophy

dissertationThis study provides a holistic view of dust storms and transport in the eastern Great Basin, and is the first to analyze the meteorological, source, and chemical characteristics of dust production in this region. First, the climatology of dust storm events affecting Salt Lake City, Utah (SLC) was assessed, and the controls on atmospheric dust generation and transport documented. Records indicate seasonal and diurnal patterns, with dust storms typically occurring in spring months during the afternoon. Since 1930, SLC had 379 dust event days (DEDs), averaging 4.7 per year, with elevated PM10 exceeding National Ambient Air Quality Standards (NAAQS) on 16 days since 1993, or 0.9 per year. Strengthening cyclonic systems are the primary producer of these dust storms. Next anthropogenically disturbed areas and barren playa surfaces were identified as the primary dust source types contributing to dust storms in the region. Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery during DEDs was analyzed to identify dust plumes, and assess the characteristics of dust source areas, which produce dust during the spring and fall and during drought. Most plumes originate from playas, classified as Barren land cover, with a silty clay soils; they often have anthropogenic disturbances, including military operations and water withdrawal. Disturbance is necessary to produce dust from vegetated landscapes in the region, evidenced by the new dust source active from 2008-2010 in the 2007 Milford Flat Fire scar, which underwent postfire land treatments. Finally, the elemental composition of dust in the region was characterized. Dust and surface soil samples were collected, resuspended, and analyzed with Sychrotron XRay Fluorescence (SXRF). Dust and soil from the eastern Great Basin are distinctly different, and identifiable. Within the dust and soil groups, however, large differences are not seen and individual samples cannot be identified by their elemental composition. Dust and soil from the eastern Great Basin tends to not be enriched in most major soil elements, excepting a large enrichment of Na in dust samples. Trace elements, however, show very large enrichment values for both dust and soil. The enrichment of dust samples has notable importance for ecosystem functioning and human health

An Active Approach to Functionality Characterization and Recognition

In this paper we focus on understanding and defining a methodology for object description and recognition both in terms of its geometrical, material and functional specifications. We define functionality in an object as its applicability toward the achievement of a task. We emphasize and develop an interactive and performatory approach to functionality recovery. Furthermore, we introduce the distinction between Inherent, Intended and Imposed functionality. By analyzing interaction and manipulation tasks as goal-oriented recognition processes we propose to identify and characterize functionalities of objects. This interaction is not only a means of verification of the hypothesized presence of functionality in objects but also a way to actively and purposively recognize the object. In order to accomplish our goal, we introduce a formal model, based on Discrete Event Dynamic System Theory, to define a task for recovering and describing functionality. We extend the recovery process to an algebra of tasks. We describe how a more complex task call be composed from a set of primitive ones. This constructive approach allows a task to be built from simpler ones in an stepwise fashion. Once the manipulatory task has been described in the formal model, it must be instantiated in a context. In such a context, the behavior of the system in which the interactio between a Manipulator, a Tool and a Target object must be observed. Thus, the description of tasks themselves provide must for means of addressing observability through different sensor modalities. For this purpose, we introduce the notion of Partial Observability of a task. This allows the description of a plant in which not all events and the time of their occurrence might he modelled and therefore predictable in advance

Design and Analysis of a Wave Energy Converter of Point Absorber Type for the Energy Extraction from the Waves

The generation of electric power from ocean waves has been in constant technological growth during the last decades, for being a clean source of abundant and renewable energy. However, the existing systems are extensive in size and cost. Thus, in this thesis, a design methodology for the construction of a wave energy prototype is developed. The proposed device is a slider-crank mechanism connected to a spherical buoy. The buoy, situated on the surface of the water, takes advantage of the vertical movement of the waves converting their oscillation movement into a rotational motion that actuates over the shaft of the armature coils within the generator to obtain electric power. The design of the mechanical components was conducted by the application of the principle of Virtual Work and D'Alembert, which allowed the determination of the dynamical model of the system; then, using these results, the mass and inertia of each element were obtained by an optimization procedure using the Optimization Toolbox of Matlab. Lastly, the results of the mathematical model were validated by experimentation in a scaled prototype of the dispositive.MaestríaMagister en Ingeniería Eléctric

Research and technology

As the NASA center responsible for assembly, checkout, servicing, launch, recovery, and operational support of Space Transportation System elements and payloads, Kennedy Space Center (KSC) is placing increasing emphasis on KSC's research and technology program. In addition to strengthening those areas of engineering and operations technology that contribute to safer, more efficient, and more economical execution of the current mission, the technological tools needed to execute KSC's mission relative to future programs are being developed. The Engineering Development Directorate encompasses most of the laboratories and other KSC resources that are key elements of research and technology program implementation and is responsible for implementation of the majority of the projects in this KSC 1990 annual report. Projects under the following topics are covered: (1) materials science; (2) hazardous emissions and contamination monitoring; (3) biosciences; (4) autonomous systems; (5) communications and control; (6) meteorology; (7) technology utilization; and (8) mechanics, structures, and cryogenics