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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.
351

Experiential Learning with Respect to Model Based Design Applied to Advanced Vehicle Development

Singh, Gurhari January 2014 (has links)
With the need for greener powertrains every more present, automakers and part suppliers are lacking skill staff to fulfill design roles. It is estimated there are over 20 million lines of software code in vehicles today and many embedded controllers. The shortage of these engineers is compounded by the economic down-turn of 2008-2009, which resulted in massive 20% to 30% layoffs, reduced internships and reduction of programs designed to recruit new talent. To increase their workforce pool, automakers are working with universities and governments operate student competitions such as EcoCAR 2: Plugging into the Future, alongside traditional private/university collaborations. These programs present students with real-world engineering challenges and the opportunities to design/construction solutions. This also exposes students to the concepts of experiential learning. The objective of this thesis will be to discuss the design, construction and operation of a vehicle for a student design competition or research group at an educational institution. A process based on model based design will be undertaken, which allows for a majority of the vehicle???s design to be completed virtually prior to vehicle prototyping. In this work the model based design method is based on General Motor???s Vehicle Design Process. A project management plan is also proposed, which breaks down tasks into three technical areas (mechanical, electrical and controls) and allows for parallelization and reduced development time will also be proposed. Finally, the resources required to operate a vehicle design team will be defined. This includes the support needed from the University, physical space, software and hardware tools, safety considerations and human capital. Examples are drawn from 2013 Chevrolet Malibu converted to a plug-in hybrid vehicle with an ethanol engine and a battery pack was designed and built. This thesis will showcase the concepts mentioned above through examples from the University of Waterloo Alternative Fuels Team and its participation in international EcoCAR 2 vehicle development competition. The conclusion is that application of the concepts did result in the successful construction of an EcoCAR 2 vehicle. Generally projects that were successful were provided with sufficient technical information from suppliers and supported with past-experiences. Recommendations include: (i) working with suppliers who are familiar with academic environments (including working with students new to vehicle design), (ii) rigorous documentation of design for future designs; and (iii) close collaboration with industry experts to review designs, manufacturing, project management and budgets.
352

Design, Modelling and Fabrication of a Hybrid Energy Harvester

Ibrahim, Mohammed January 2014 (has links)
As sources of energy are becoming more scarce and expensive, energy harvesting is receiving more global interest and is currently a growing field. Energy harvesting is the process of converting ambient energy, such as vibration, to electrical energy that can power a multitude of applications. Vibration energy is the by-product of everyday life; it is generated from any perceivable activity. While typically viewed as noise, there is a strong potential for harvesting this energy and deploying it to useful applications. The focus of this thesis will be using vibration as the ambient source of energy. Hybrid energy harvesters employ more than one of the harvesting technologies. In this thesis, two hybrid harvesters that utilize piezoelectric, magnetostrictive, and electromagnetic technologies are designed, modelled, and tested. Both of these harvesters have beams that are spiral in shape. The use of the spiral geometry allows the system to have a lower natural frequency as opposed to the traditional cantilever beam, while still maintaining a high volume of active material. The first harvester that is discussed is the P-MSM harvester. It utilizes piezoelectric and magnetostrictive material. Both materials are configured in a spiral beam geometry and allowed to resonate independently. The resonance frequency of these two materials is designed to create wideband energy harvesting. This allows the harvester to be operating efficiently even if the ambient vibration shifts a small amount. The second harvester that is discussed is the P-MAG harvester. It utilizes piezoelectric and electromagnetic technologies. It also incorporates a spiral geometry for the piezoelectric layers and includes a magnet attached at the centre. The magnet is placed in the centre of the spiral to reduce the natural frequency of the system and to also actively contribute to the harvesting. This harvester has two sources operating at the same resonant frequency, which allows it to have a larger power output than if the sources were separated. Finally, finite element analysis was used to model both harvesters. ANSYS was used for the piezoelectric material and COMSOL was used for the electromagnetic material. The results are compared to the experimental and are in good agreement.
353

Methods for Testing and Analyzing Lithium-Ion Battery Cells intended for Heavy-Duty Hybrid Electric Vehicles

Svens, Pontus January 2014 (has links)
Lithium-ion batteries designed for use in heavy-duty hybrid vehicles are continuously improved in terms of performance and longevity, but they still have limitations that need to be considered when developing new hybrid vehicles.                The aim of this thesis has been to study and evaluate potential test and analysis methods suitable for being used in the design process when maximizing lifetime and utilization of batteries in heavy-duty hybrid vehicles. A concept for battery cell cycling on vehicles has been evaluated. The work included development of test equipment, verification of hardware and software as well as an extended period of validation on heavy-duty trucks. The work showed that the concept has great potential for evaluating strategies for battery usage in hybrid vehicles, but is less useful for accelerated aging of battery cells.                             Battery cells encapsulated in flexible packaging material have been investigated with respect to the durability of the encapsulation in a demanding heavy-duty hybrid truck environment. No effect on water intrusion was detected after vibration and temperature cycling of the battery cells.                    Aging of commercial battery cells of the type lithium manganese oxide - lithium cobalt oxide / lithium titanium oxide (LMO-LCO/LTO) was investigated with different electrochemical methods to gain a deeper understanding of the origin of performance deterioration, and to understand the consequences of aging from a vehicle manufacturer's perspective. The investigation revealed that both capacity loss and impedance rise were largely linked to the positive electrode for this type of battery chemistry.                           Postmortem analysis of material from cycle-aged and calendar-aged battery cells of the type LMO-LCO/LTO and LiFePO4/graphite was performed to reveal details about aging mechanisms for those cell chemistries. Analysis of cycle-aged LMO-LCO/LTO cells revealed traces of manganese in the negative electrode and that the positive electrode exhibited the most severe aging. Analysis of cycle-aged LFP/graphite cells revealed traces of iron in the negative electrode and that the negative electrode exhibited the most severe aging. / Litiumjonbatterier anpassade för användning i tunga hybridfordon förbättras kontinuerligt med avseende på prestanda och livslängd men har fortfarande begränsningar som måste beaktas vid utveckling av nya hybridfordon.                 Syftet med denna avhandling har varit att studera och utvärdera potentiella prov- och analysmetoder lämpliga för användning i arbetet med att maximera livslängd och utnyttjandegrad av batterier i tunga hybridfordon.                               Ett koncept för battericykling på fordon har utvärderats. Arbetet innefattade utveckling av testutrustning, verifiering av hårdvara och mjukvara samt en längre periods validering på lastbilar. Arbetet har visat att konceptet har stor potential för utvärdering av strategier för användandet av batterier i hybridfordon, men är mindre användbar för åldring av batterier.                                Batterier kapslade i flexibelt förpackningsmaterial har undersökts med avseende på kapslingens hållbarhet i en krävande hybridlastbilsmiljö. Ingen påverkan på fuktinträngning kunde påvisas efter vibration och temperaturcykling av de testade battericellerna.                     Åldring av kommersiella battericeller av typen litiummanganoxid - litiumkoboltoxid/litiumtitanoxid (LMO-LCO/LTO) undersöktes med olika elektrokemiska metoder för att få en djupare förståelse för prestandaförändringens ursprung och för att förstå konsekvenserna av åldrandet ur en fordonstillverkares användarperspektiv. Undersökningen visade att både kapacitetsförlust och impedanshöjning till största delen var kopplat till den positiva elektroden för denna batterityp.                  Post-mortem analys av material från cyklade och kalenderåldrade kommersiella battericeller av typen LMO-LCO/LTO och LiFePO4/grafit utfördes för att avslöja detaljer kring åldringsmekanismerna för dessa cellkemier. Vid analys av cyklade LMO-LCO/LTO celler påvisades mangan i den negativa elektroden samt uppvisade den positiva elektroden kraftigast åldring. Vid analys av cyklade LFP/grafit celler påvisades järn i den negativa elektroden samt uppvisade den negativa elektroden kraftigast åldring. / <p>QC 20140520</p>
354

A real-time hybrid vehicle control strategy and testing platform

Wise, Jeremy 15 July 2011 (has links)
In this paper, the need to develop a control strategy and test apparatus for next generation hybrid vehicles was realized. The complexity of today’s and future hybrid vehicles necessitates the need for an equally advanced method of control that can extract the optimal fuel economy from the system as a whole. A review of existing hybrid vehicle control strategies was performed. Overall, much research has been done on the optimization of series and parallel type vehicles, but virtually no information was found on the optimal use of advanced powersplit drivetrains. However, the control strategy concepts explored in the literature are useful, and can be extended to complex architectures like the General Motors Two-Mode design. The equivalent consumption minimization strategy (ECMS) method developed by Rizzoni et al at the Ohio State University has proven to be a well developed control strategy that has seen much progress over the last decade. Although it has been only demonstrated on parallel-type vehicles, it was chosen as the basis for the control strategy methodology. An in-depth analysis on the Two-Mode transmission operation was performed. The fundamental equations for each of its range states were derived for future use in developing a plant model, and for use in control strategy development. The torque and speed capabilities of each of its modes and gears were analysed. A detailed plant model was created to form a virtual test bed for control strategy development purposes. The models use empirical data provided by manufactures, which ensures a reasonable level of accuracy in portraying component constraints and efficiencies. Building on the ECMS, a similar hybrid vehicle control strategy was developed for Two-Mode transmission based vehicles. It was modified to handle two degrees of freedom as required by the system. Its objective is to constantly minimize the total equivalent power use in the system which is defined as the sum of the chemical power in the fuel and the power used by the battery multiplied by an equivalency factor. Overall, the control strategy provides a strong basis for the optimal control of nextgeneration hybrid vehicles incorporating powersplit transmissions. It is suggested that further research be explored in combining rule-based control methods with the developed optimization based method since rule-based methods can add the stability required for enhanced drivability. / Graduate / 10000-01-01
355

Modeling and Simulation of a Hybrid Electric Vessel

Jaster, Tiffany 03 January 2014 (has links)
A proposed hybrid electric marine vehicle was modeled in MATLAB Simulink and SimPowerSystems. Models for each of the individual propulsion components were developed and incorporated into a complete hybrid electric propulsion model. A vessel resistance model was created to support vessel performance and energy requirement evaluation. The model incorporates data based on the ship principal parameters and hull form. A rule-based supervisory controller for the proposed vessel was constructed. It is an amalgamation of control strategies of three vehicle architectures: electric vehicle, fuel cell electric vehicle, and hybrid electric vehicle (HEV). The complete model of the hybrid electric propulsion, control, and resistance subsystems was simulated on a dSPACE hardware-in-the-loop platform. For each simulation, the energy storage system (ESS) state of charge, station keeping/cruising mode, HEV assist, Beaufort number, current speed, true wind angle, and hotel load were specified. From the simulations, it was demonstrated that using a 30% ESS assisted HEV mode results in reduced emissions and fuel consumption as compared to a conventional vessel powertrain mode, supporting the case for plug-in hybrid electric vessels. A larger capacity ESS has the potential to reduce emissions and fuel consumption further, depending on ship usage. The basic rule-based supervisory controller proved functional for facilitating adequate power flows; however, further development is needed to improve efficiency and the mode selection process. / Graduate / 0548
356

Corpus-based connectionist parsing

Tepper, Jonathan Andrew January 2000 (has links)
No description available.
357

An environment for programming a PUMA 260 work cell /

McConney, Eric. January 1986 (has links)
No description available.
358

Magnetic Attitude Control of Microsatellites In Geocentric Orbits

Dutia, Jiten 18 March 2013 (has links)
Attitude control of spacecraft in low Earth orbits can be achieved by exploiting the torques generated by the geomagnetic field. Recent research has demonstrated that attitude stability of a spacecraft is possible using a linear combination of Euler parameters and angular velocity feedback. The research carried out in this thesis implements a hybrid scheme consisting of magnetic control using on-board dipole moments and a three-axis actuation scheme such as reaction wheels and thrusters. A stability analysis is formulated and analyzed using Floquet and Lyapunov stability theorems.
359

A Development of Design and Control Methodology for Next Generation Parallel Hybrid Electric Vehicle

Lai, Lin 02 October 2013 (has links)
Commercially available Hybrid Electric Vehicles (HEVs) have been around for more than ten years. However, their market share remains small. Focusing only on the improvement of fuel economy, the design tends to reduce the size of the internal combustion engine in the HEV, and uses the electrical drive to compensate for the power gap between the load demand and the engine capacity. Unfortunately, the low power density and the high cost of the combined electric motor drive and battery packs dictate that the HEV has either worse performance or much higher price than the conventional vehicle. In this research, a new design philosophy for parallel HEV is proposed, which uses a full size engine to guarantee the vehicle performance at least as good as the conventional vehicle, and hybridizes with an electrical drive in parallel to improve the fuel economy and performance beyond the conventional cars. By analyzing the HEV fuel economy versus the increasing of the electrical drive power on typical driving conditions, the optimal hybridization electric power capacity is determined. Thus, the full size engine HEV shows significant improvement in fuel economy and performance, with relatively short cost recovery period. A new control strategy, which optimizes the fuel economy of parallel configured charge sustained hybrid electric vehicles, is proposed in the second part of this dissertation. This new approach is a constrained engine on-off strategy, which has been developed from the two extreme control strategies of maximum SOC and engine on-off, by taking their advantages and overcoming their disadvantages. A system optimization program using dynamic programming algorithm has been developed to calibrate the control parameters used in the developed control strategy, so that the control performance can be as close to the optimal solution as possible. In order to determine the sensitivity of the new control strategy to different driving conditions, a passenger car is simulated on different driving cycles. The performances of the vehicle with the new control strategy are compared with the optimal solution obtained on each driving condition with the dynamic programming optimization. The simulation result shows that the new control strategy always keeps its performance close to the optimal one, as the driving condition changes.
360

Multidisciplinary Optimization of Hybrid Electric Vehicles: Component Sizing and Power Management Logic

Fan, Brian Su-Ming 15 June 2011 (has links)
A survey of the existing literature indicates that optimization on the power management logic of hybrid electric vehicle is mostly performed after the design of the powertrain architecture or the power source components are finalized. The goal of this research is to utilize Multidisciplinary Design Optimization (MDO) to automate and optimize the vehicle’s powertrain component sizes, while simultaneously determining the optimal power management logic in developing the most cost-effective system solution. A generic, modular, and flexible vehicle model utilizing a backward-looking architecture is created using scalable powertrain components. The objective of the research work is to study the energy efficiency of the vehicle system, where the dynamics of the vehicle is not of concern; a backward-looking architecture could be used to compute the power consumption and the overall efficiency accurately while minimizing the required computing resource. An optimization software platform utilizing multidisciplinary design optimization approach is implemented containing the generic vehicle model and an optimizer of the user’s choice. The software model is created in the MATLAB/Simulink environment, where the optimization code and the powertrain component properties are implemented using m-files, and the power consumption calculations of the vehicle system are performed in Simulink. Furthermore, a feature-based optimization technique is developed with the motivation of significantly reducing the simulation run-time. To demonstrate the capabilities of the developed approach and contributions of the research, two optimization case studies are undertaken: (i) series hybrid electric vehicles, and (ii) police vehicle anti-idling system. As the first case study, a plug-in battery-only series hybrid electric vehicle with similar power components as the Chevrolet Volt is created, where the battery size and the power management logic are simultaneously optimized. The objective function of the optimizer is defined from the financial cost perspective, where the objective is to minimize the initial cost of batteries, gasoline and electricity consumption over a period of five years, and the carbon tax as a penalty function for fuel emissions. The battery-only series hybrid electric vehicle is subsequently extended to include ultracapacitors, and the optimization process is expanded to the rest of the powertrain components and power management logic. A comparison between the optimization algorithms found that only genetic algorithm (GA) was capable of finding the optimal solution during a full simulation, while simulated annealing and pattern search were not able to converge to any solution after a 24-hour period. A comparison between the full genetic algorithm optimization and the feature-based (FB) method with secondary optimization found that although the final cost function of the FB methodology is higher than that of the full GA optimization, the total simulation run-time is approximately ten times less using the FB method. The behaviour of the solutions found via both methods exhibited almost identical characteristics, further confirming the validity of the feature-based methodology. Finally, a benchmarking comparison found that with more accurate manufacturers’ component data and additional appropriate performance requirements, the proposed software platform will be capable of predicting a solution that is comparable to the Chevrolet Volt. The second case study involves optimizing an anti-idling system for police vehicles using the same optimization algorithm and generic vehicle model. The goal of the optimization study is to select an additional battery and determine the power management logic to reduce the engine idling time of a police vehicle. It is found that depending on the SOC threshold, the duration of time over which the engine is activated varies in a non-linear fashion, where local minima and maxima exist. A design study confirmed that by utilizing the anti-idling system, significant cost reduction can be realized when compared to one without the anti-idling system. A comparison between the various optimization algorithms showed that the feature-based optimization can obtain a relatively accurate solution while reducing simulation time by approximately 90%. This significant reduction in simulation time warrants the feature-based optimization technique a powerful tool for vehicle design. Due to the high cost of the electrical energy storage components, it is currently still more cost-effective to use the fossil fuel as the primary energy source for transportation. However, given the rise of fuel cost and the advancement in the electrical energy storage technology, it is inevitable that the cost of the electrical and chemical energy storage method will reach a balance point. The proposed optimization platform allows the user the capability and flexibility to obtain the optimal vehicle solution with ease at any given time in the future.

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