Dissertations / Theses on the topic 'Automobiles Speed Mathematical models'
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Tchikanda, Serge William. "Modeling for high-speed high-strength precision optical fiber drawing." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/20051.
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Hudson, Dominic A. "A validation study on mathematical models of speed and frequency dependence in seakeeping of high speed craft." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299687.
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Ye, Qing, and 叶青. "Short-term traffic speed forecasting based on data recorded at irregular intervals." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47250732.
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Efficient and comprehensive forecasting of information is of great importance
to traffic management. Three types of forecasting methods based on irregularly
spaced data—for situations when traffic detectors cannot be installed to generate
regularly spaced data on all roads—are studied in this thesis, namely, the single
segment forecasting method, multi-segment forecasting method and model-based
forecasting method.
The proposed models were tested using Global Positioning System (GPS) data
from 400 Hong Kong taxis collected within a 2-kilometer section on Princess
Margaret Road and Hong Chong Road, approaching the Cross Harbour Tunnel.
The speed limit for the road is 70 km/h. It has flyovers and ramps, with a small
number of merges and diverges. There is no signalized intersection along this road
section. A total of 14 weeks of data were collected, in which the first 12 weeks of
data were used to calibrate the models and the last two weeks of data were used for
validation.
The single-segment forecasting method for irregularly spaced data uses a
neural network to aggregate the predicted speeds from the naive method, simple
exponential smoothing method and Holt’s method, with explicit consideration of
acceleration information. The proposed method shows a great improvement in
accuracy compared with using the individual forecasting method separately. The
acceleration information, which is viewed as an indicator of the phase-transition
effect, is considered to be the main contribution to the improvement.
The multi-segment forecasting method aggregates not only the information
from the current forecasting segment, but also from adjacent segments. It adopts the
same sub-methods as the single-segment forecasting method. The forecasting
results from adjacent segments help to describe the phase-transition effect, so that
the forecasting results from the multi-segment forecasting method are more
accurate than those that are obtained from the single segment forecasting method.
For one-second forecasting length, the correlation coefficient between the forecasts
from the multi-segment forecasting method and observations is 0.9435, which
implies a good consistency between the forecasts and observations.
While the first two methods are based on pure data fitting techniques, the third
method is based on traffic models and is called the model-based forecasting
method. Although the accuracy of the one-second forecasting length of the
model-based method lies between those of the single-segment and multi-segment
forecasting methods, its accuracy outperforms the other two for longer forecasting
steps, which offers a higher potential for practical applications.published_or_final_version
Civil Engineering
Master
Master of Philosophy
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Watson, Cody. "Modeling of pressure transients in fuel injection lines." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/16869.
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Roberts, Craig Arnold. "Modeling the relationships between microscopic and macroscopic travel activity on freeways : bridging the gap between current travel demand models and emerging mobile emission models." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/32873.
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Page, Karen Mary. "Mathematical models in embryology : the selection, regulation and speed of formation of patterns." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302119.
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Pratikakis, Nikolaos. "Mathematical modeling of rail gun." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Sep%5FPratikakis.pdf.
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Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, September 2006.Thesis Advisor(s): Kwon Young. "September 2006." Includes bibliographical references (p. 77-78). Also available in print.
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Na, Xiaoxiang. "Game theoretical modelling of a driver's interaction with active steering." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708392.
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Uzelac, Lawrence Stevan. "A Multiple Coupled Microstrip Transmission Line Model for High-Speed VLSI Interconnect Simulation." PDXScholar, 1991. https://pdxscholar.library.pdx.edu/open_access_etds/4526.
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A model is presented which incorporates the advantages of a mixed mode simulation to characterize transmission line behavior in multiple coupled Transmission line systems. The model is intended for use by digital circuit designers who wish to be able to obtain accurate transmission line behavior for complex digital systems for which continuous time simulation tools such as SPICE would time prohibitive. The model uses a transverse electromagnetic wave approximation to obtain solutions to the basic transmission line equations. A modal analysis technique is used to solve for the attenuation and propagation constants for the transmission lines. Modal analysis done in the frequency domain after a Fast Fourier Transform of the time-domain input signals. Boundary conditions are obtained from the Thevinized transmission line input equivalent circuit and the transmission line output load impedance. The model uses a unique solution queue system that allows n-line coupled transmission lines to be solved without resorting to large order matrix methods or the need to diagonals larger matrices using linear transformations. This solution queue system is based on the method of solution superposition. As a result, the CPU time required for the model is primarily a function of the number of transitions and not the number of lines modeled. Incorporation of the model into event driven circuit simulators such as Network C is discussed. It will be shown that the solution queue methods used in this model make it ideally suited for incorporation into a event-driven simulation network. The model presented in this thesis can be scaled to incorporate direct electromagnetic coupling between first, second, or third lines adjacent to the line transitioning. It is shown that modeling strictly adjacent line coupling is adequate for typical digital technologies. It is shown that the model accurately reproduces the transmission line behavior of systems modeled by previous authors. Example transitions on a 8-line system are reviewed. Finally, future model improvements are discussed.
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Lim, Teck-Bin. "A unified computational fluid dynamics-aeroacoustics analysis of high speed propeller." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/12064.
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Leo, Angela A. "A numerical approach to calculating population spreading speed." Link to electronic thesis, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-040207-193250/.
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Eusuff, M. Muzaffar. "Optimisation of an operating policy for variable speed pumps using genetic algorithms." Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09ENS/09ense91.pdf.
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Undertaken in conjunction with JUMP (Joint Universities Masters Programme in Hydrology and Water Resources). Bibliography: leaves 76-83. Establishes a methodology using genetic algorithms to find the optimum operating policy for variable speed pumps in a water supply network over a period of 24 hours.
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Guzzomi, Andrew Louis. "Torsional vibration of powertrains : an investigation of some common assumptions." University of Western Australia. School of Mechanical Engineering, 2007. http://theses.library.uwa.edu.au/adt-WU2008.0032.
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The area of powertrain dynamics has received considerable attention over a number of years. The recent introduction of more stringent emission requirements together with economic pressure has led to a particular focus on increasing powertrain efficiency. This has seen the incorporation of on-board, real-time measurements to predict system behaviour and engine condition. In this domain, accurate models for all powertrain components are important. One strategy to improve accuracy is to evaluate the assumptions made when deriving each model and then to address the simplifications that may introduce large errors. To this end, the aim of the work presented in this dissertation was to investigate the consequences of some of the more common assumptions and simplifications made in low frequency torsional powertrain models, and to propose improved models where appropriate. In particular, the effects of piston-tocylinder friction, crank/gudgeon pin offset, and the torsional behaviour of tyres were studied. Frequency and time domain models were used to investigate system behaviour and model predictions were compared with measurements on a small single cylinder engine. All time domain engine and powertrain models also include a variable inertia function for each reciprocating mechanism. It was found that piston-to-cylinder friction can increase the apparent inertia variation of a single reciprocating engine mechanism. This has implications for the nonlinear behaviour of engines and the drivetrains they are connected to. The effect of crank/gudgeon pin offset also modified the nonlinear behaviour of the mechanism. Though, for typical (small) gudgeon offset values these effects are small. However, for large offset values, achievable practically with crank offset, the modification to the nonlinear behaviour should not be ignored. The low frequency torsional damping properties of a small pneumatic tyre were found to be more accurately represented as hysteretic rather than viscous. Time domain modelling was then used to extend the results to a multi-cylinder engine powertrain and was achieved using the Time Domain Receptance (TDR) method. Various powertrain component TDRs were developed using Laplacians. Powertrain simulations showed that piston-to-cylinder friction can provide additional excitation to the system.
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Brueckner, Frank Peter. "Finite element analysis of high-speed flows with application to the ram accelerator concept." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185417.
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A Petrov-Galerkin method for the solution of the compressible Euler and Navier-Stokes equations is presented. The method is based on the introduction of an anisotropic balancing diffusion in the local direction of the propogation of the scalar variables. The direction in which the diffusion is added and its magnitude are automatically calculated locally using a criterion that is optimal for one-dimensional transport equations. Algorithms are developed using bilinear quadrilateral and linear triangular elements. The triangular elements are used in conjunction with an adaptive scheme using unstructured meshes. Several applications are presented that show the exceptional stability and accuracy of the method, including the ram accelerator concept for the acceleration of projectiles to ultrahigh velocities. Both two-dimensional and axisymmetric models are employed to evaluate multiple projectile configurations and flow conditions.
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Shafi, Ghufran. "Development of roadway link screening criteria for microscale carbon monoxide and particulate matter conformity analyses through application of classification tree model." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28222.
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Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2008.Committee Chair: Guensler, Randall; Committee Member: Rodgers, Michael; Committee Member: Russell, Armistead.
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Lee, Kwangju. "Modeling and identification of flexible joints in vehicle structures." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39704.
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A simple, design-oriented model of joints in vehicle structures is developed. This model accounts for the flexibility, the offsets of rotation centers of joint branches, and the coupling between rotations of a joint branch in different planes. The model parameters consist of torsional spring rates, the coordinates of the flexible hinges, and the orientations of planes in which the torsional springs are located. The model parameters are selected to be physically meaningful. In some cases, the behavior of joints can be accurately represented by using simpler models. The conditions under which the joint model can be simplified are discussed. A family of joint models with different levels of complexity are also defined.
A probabilistic system identification is used to estimate the joint parameters by using the measured displacements. The parameters are estimated by minimizing the discrepancies between the measured and predicted displacements. Statistical tests which identify important parameters are also presented. These tests can be used to simplify the joint models without significantly reducing the accuracy in predicting structural responses.
The identification methodology is applied to automotive structures with joints and also to isolated subassemblies consisting of joints and attached branches.Ph. D.
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Stott, Shannon Leigh. "Kinetic Study of Intracellular Ice Formation in Micropatterned Endothelial Cell Cultures Using High Speed Video Cryomicroscopy." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/16256.
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Intracellular ice formation (IIF), a major cause of cryoinjury in biological cells, is significantly more pronounced during freezing of tissue than during freezing of suspended cells. While extensive studies of IIF have been conducted for single cells in suspension, few have investigated IIF in tissue. Due to the increased complexity that arises from both cell-substrate and cell-cell interactions in tissue, knowledge of cryobiology of isolated cells cannot simply be extrapolated to tissue. Different theories have been hypothesized for the mechanisms of IIF in tissue, but none have been conclusively proven. Towards the goal of developing mathematical models to accurately predict the probability of IIF in tissues of one or more cell types, we have developed a novel high-speed video cryomicroscopy system capable of image acquisition at sampling rates up to 32,000 Hz. Specifically, the effects of cell adhesion to the substrate and cell-cell interactions were investigated with experimental (micropatterned endothelial cell constructs) and mathematical models (Monte Carlo simulations). We have reported the first direct observations of the IIF process recorded at unprecedented sub-millisecond and sub-micron resolution. For the majority of our experiments, IIF nucleation was determined to occur preferentially at the cell perimeter. This observation was not consistent with the commonly accepted hypotheses of ice nucleation in suspended cells and suggests that an alternative mechanism of IIF initiation is dominant in adherent cells. In addition, the kinetics of ice nucleation were shown to be influenced by time in culture, attached cell perimeter, fibronectin coating density, and degree of cell-cell contact. Moreover, an additional phenomenon, paracellular ice penetration was identified, and the frequency of formation was correlated with focal adhesion formation. The data and mathematical models presented in this thesis bring closer the goal of elucidating the primary mechanisms contributing to IIF in tissue; providing important contributions to both the fields of cryopreservation (minimizing IIF) and cryosurgery (maximizing IIF).
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Griette, Quentin. "Mathematical and numerical analysis of propagation models arising in evolutionary epidemiology." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS051/document.
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Cette thèse porte sur différents modèles de propagation en épidémiologie évolutive. L'objectif est d'en faire une analyse mathématique rigoureuse puis d'en tirer des enseignements biologiques. Dans un premier temps nous envisageons le cas d'une population d'hôtes répartis de manière homogène dans un espace linéaire, dans laquelle se propage un pathogène pouvant muter entre deux phénotypes plus ou moins virulents. Ce phénomène de mutation est à l'origine d'une interaction entre les dynamiques évolutive et épidémiologique du pathogène. Nous étudions la vitesse de propagation de l'épidémie et l'existence de fronts progressifs, ainsi que l'influence sur la vitesse de différents facteurs biologiques, comme des effets stochastiques liés à la taille de la population d'hôtes (explorations numériques). Dans un deuxième temps nous envisageons une hétérogénéité spatiale périodique dans la population d'hôtes, et l'existence de fronts pulsatoires pour le système de réaction-diffusion (non-coopératif) associé. Enfin nous considérons un pathogène pouvant muter vers un grand nombre de phénotypes différents et étudions l'existence de fronts potentiellement singuliers, modélisant ainsi une concentration sur un trait optimalIn this thesis we consider several models of propagation arising in evolutionary epidemiology. We aim at performing a rigorous mathematical analysis leading to new biological insights. At first we investigate the spread of an epidemic in a population of homogeneously distributed hosts on a straight line. An underlying mutation process can shift the virulence of the pathogen between two values, causing an interaction between epidemiology and evolution. We study the propagation speed of the epidemic and the influence of some biologically relevant quantities, like the effects of stochasticity caused by the hosts' finite population size (numerical explorations), on this speed. In a second part we take into account a periodic heterogeneity in the hosts' population and study the propagation speed and the existence of pulsating fronts for the associated (non-cooperative) reaction-diffusion system. Finally, we consider a model in which the pathogen is allowed to shift between a large number of different phenotypes, and construct possibly singular traveling waves for the associated nonlocal equation, thus modelling concentration on an optimal trait
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Forooqi, A. Masood. "Ridership studies for the proposed Florida high speed rail system." FIU Digital Commons, 1990. http://digitalcommons.fiu.edu/etd/3254.
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Florida, the fourth largest and sunshine state, is growing at the rate of 800 new residents daily.!! By the year 2000 the population is estimated to be 16 Million, and the annual tourists at 80 Million, generating 40 Million trips.
The proposed High Speed Rail will connect Miami and West Palm Beach to Orlando and Tampa. This 325-mile corridor represents 70 % of all the "Socio-Economic Resources" of the whole of Florida and the trend will continue well into the next century. The Miami-Orlando ride will reduce to 2 hours speeding at up to 150 mph. It will be operational by 1995 and the system is estimated to cost 4.6 Billion Dollars.
One of the major problems encountered by the new High Speed Rail (HSR) is the "RIDERSHIP FORECASTING," In the United States there is a lack of current information about the Total Volume of Intercity Trips and the Specific Characteristics of the Trips that determines a willingness to use HSR. The Quality, Comprehensiveness, and Acceptability, by the forecasts must be sufficient to generate Public Support, Confidence, and Response for the Implementation of HSR.
The THESIS discusses the various Ridership Forecasting Techniques and chooses the “Most Suitable Model” applicable to conditions in South and Central Florida.
A “Model Choice Based Model” is selected called, “THE LOGIT FUNCTION”, which takes into account, the Floridian Choice of available Travel Modes, and the Factors Affecting the Manner of the “Decision making Process”, in Favour of a Particular Mode. Evaluating Business and Non-Business Travel for the Internal Trips, (including the Induced Demand and the Short Trips) and the External Trips. The External and Short Trips were Not considered by Previous Studies. The standard guidelines for “Revenue and Ridership Forecasting,” by High Speed Rail Association are closely followed in this Study. Due consideration is also given to Socio-Economic data involving population, wealth, average per capita income, number of families, size of labor force, number of hotel / motel rooms and college enrollment. A Survey was carried out, to collect the data and to test the Sensitivity, under given set of conditions and scenarios.
The studies conclude that HSR is a Feasible Project and by the year 2000, the Ridership will be 3.8 Million Annual Trips. The future studies will continue to improve the results, as an individual’s attitude and response towards HSR Travel becomes better known and recorded in Florida
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Berger, Rémi. "Intégration et validation expérimentale de la méthode VOF dans les calculs aérodynamiques automobiles: application au cas de l'entrainement d'eau dans les circuits de climatisation." Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210049.
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Cette étude porte sur l'utilisation conjointe (appelée ” couplage ”) de modèle de turbulence à grandes échelles LES (Large Eddy Simulation) et du modèle multiphasique VOF (Volume of Fluid). Cette utilisation conjointe est nécessaire dans de nombreuses applications industrielles comme celles de l'automobile où l'on recherche par exemple à évaluer les prestations diphasiques de l'auvent liées au phénomène d'entraînement et d'ingestion d'une nappe d'eau par le HVAC (système d'air conditionné). Cependant, l'utilisation conjointe de ces méthodes nécessite un traitement particulier de la turbulence proche de la surface liquide afin de reproduire convenablement la quantité de mouvement transmise depuis la phase gazeuse, motrice, jusque dans la phase liquide.Basée sur une approche numérique et expérimentale, notre étude est articulée autour de trois axes. Tout d'abord, le développement de techniques de mesures spécifiques pour l'étude expérimentale de notre problématique: le LeDaR pour mesurer les déformées d'une interface et la PIV d'interface afin d'accéder aux champs de vitesse et de turbulence dans chacune des deux phases. Le second axe est la constitution d'une base de données expérimentales sur une configuration de type jet impactant sur une surface liquide représentative des phénomènes rencontrés dans l'auvent. Enfin, le troisième axe de travail est l'évaluation des modèles existants dans le code Ansys Fluent et à partir de cette analyse le développement et la validation de modèles de couplage LES-VOF.
L'évaluation des modèles développés a permis de valider une stratégie de calcul adaptée aux simulations de l'entraînement d'une surface d'eau par un écoulement d'air turbulent.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
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Berg, Allison M. "The feasibility of sodar wind profile measurements from an oceanographic buoy." Thesis, (37 MB), 2006. http://handle.dtic.mil/100.2/ADA471871.
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Thesis (M.S.)--Massachusetts Institute of Technology at Woods Hole Oceanographic Institution, 2006."September 2006." Description based on title screen as viewed on June 8, 2010. DTIC Descriptor(s): Doppler Radar, Wind Velocity, Sound Ranging, Doppler Sonar, Buoys, Measurement, Motion, Oceanographic Equipment, Theses DTIC Identifier(s): Doppler Sodar, Sodar (Sound Detection and Ranging), ASIS Includes bibliographical references (leaf 75). Also available in print.
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Rim, Geun-hie. "Variable speed constant frequency power conversion with permanent magnet synchronous and switched reluctance generators." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/40015.
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Husted, Christopher. "Improving the efficiency of assigning vehicles to auto carrier loads : a decision support system." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/18129.
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Thesis (MBA)--Stellenbosch University, 2008.ENGLISH ABSTRACT: Auto Carrier Transport (ACT) is the motor ferrying division of Grindrod South Africa (Pty) Ltd and is contracted to transport the product of 15 different vehicle manufacturers. The division is responsible for ensuring that the combined annual volumes of each contract, totalling over 300 000 vehicles per year, are delivered to the right place, at the right time, and in the right condition. ACT's operating mandate thus focuses on the outbound logistics of new vehicles, which implies moving cars from either the local manufacturing plants, or from the import facilities at the ports, to the respective dealer networks all across Southern Africa. One of the key operational processes regarding the transportation of vehicles is the allocation of cars to carrier loads, also known as load building. Once cars have been allocated to a load, a carrier is then used to transport the load. The existing load building operation is completely manual, with operators simply assigning cars to loads as best they see fit. No support systems exist. Thus, given the complexity of the load building problem, and the manual processes used, existing load building practices result in suboptimal payload performances. A Linear Programming Model was developed to improve the manner in which vehicles are categorised, and then assigned to loads. When compared against the results of load building operators, it was found that the model could potentially improve the company's contribution margin by 5.8 percent.
AFRIKAANSE OPSOMMING: Auto Carrier Transport (ACT) is die motorvoertuig vervoerafdeling van Grindrod Suid Afrika (Edms) Bpk en word gekontrakteer vir die vervoer van die produkte van 15 verskillende motorvervaardigers. Die afdeling is verantwoorde1ik om te verseker dat die jaarlikse volume van elke kontrak (met 'n gekombineerde volume van meer as 300 000 motorvoertuie per jaar) betyds afgelewer word, op die regte plek en in die regte toestand. ACT se operasionele mandaat fokus dus op die uitgaande logistiek van nuwe motorvoertuie met die implikasie dat motorvoertuie vanaf die plaaslike vervaardingsaanleg, of die invoer fasiliteit by die hawens, na die ooreenstemende handelaarsnetwerke in Suider Afrika vervoer word. Een van die kern operasionele prosesse rakende die vervoer van motorvoertuie, wat bekendstaan as vragtoekening, is die toedeling van motorvoertuie tot vragmotor vragte. Sodra 'n motorvoertuig aan 'n vrag toegeken is, word dit deur middel van 'n vragmotor vervoer. Die bestaande vragtoekeningsproses word per hand uitgevoer deur operateurs wat eenvoudig motorvoertuie aan vragte toedeel soos hulle goeddink sonder die gebruik van enige besluitnemingsondersteuningstelsels. Aangesien vragtoekening 'n baie komplekse probleem is wat per hand uitgevoer word, is die resultate suboptimaal. 'n Lineêre programeeringsmodel is ontwikkel om die klassifikasie van motorvoertuie te verbeter waarna die motorvoertuie aan vragte toegeken word. In 'n vergelyking tussen die model se resultate en die van die operateurs is daar bevind dat die model die maatskappy se wins per eenheid met 5.8 persent kan verbeter.
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Mazumdar, Sanjay Kumar. "Adaptive control of nonlinear systems using neural networks /." Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phm476.pdf.
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Gonçalves, Maria Aline. "Controle SDRE aplicado em suspensão veicular com amortecedor magneto-reológico." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2533.
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Desde que se inventou o automóvel, a suspensão veicular é objeto de pesquisa e estudo. A função do sistema de suspensão de um veículo é minimizar a aceleração vertical, isolando os passageiros de choques e vibrações promovendo conforto, reduzindo a fadiga o que beneficia a saúde e segurança dos motoristas. Este trabalho apresenta uma proposta para o controle da suspensão veicular utilizando um controlador SDRE aplicado ao amortecedor magneto-reológico. A eficiência do controle proposto pode ser evidenciada através de simulações computacionais utilizando um modelo matemático não linear de um quarto de carro e um modelo matemático não-lienar de meio de carro. A análise do desempenho do controle é realizada considerando excitações provocadas por irregularidades da estrada representadas por entradas do tipo degrau e senoidal. As simulações computacionais foram realizadas utilizando o programa Matlab®. Os resultados das simulações evidenciam que o controle proposto melhora dirigibilidade do veículo ao reduzir o deslocamento vertical do conjunto eixo-roda e contribui com o conforto dos passageiros reduzindo as oscilações na carroceria. Adicionalmente, foram realizadas análises de simulações de variações paramétricas afim de se verificar o comportamento do controle proposto diante de incertezas. Os estudos paramétricos demonstram que o controle permanece estável, mesmo quando submetido a variações paramétricas.Since car was developed, vehicular suspension is an object of research and study. The function of the suspension system of a vehicle is to minimize vertical acceleration, isolating passengers from shocks and vibrations promoting comfort, reducing fatigue which benefits the health and safety of drivers. This work presents a proposal for the control of vehicle suspension using an SDRE controller applied to the magneto-rheological damper. The efficiency of the proposed control can be evidenced through computational simulations using a quarter-car nonlinear mathematical model and a half-car nonlinear mathematical model. The analysis of the controller's performance is performed considering the excitations caused by irregularities of the road represented by step input and sinusoidal. Computational simulations were performed using Matlab®. The simulation results show that the proposed control improves the vehicle's dirigibility by reducing the vertical displacement of the wheel and also contributes to the passengers' comfort by reducing oscillations in the vehicle's body. In addition, simulations of parametric variations were performed in order to verify the behavior of the proposed control in face of uncertainties. Parametric studies demonstrate that control remains stable, even when subjected to parametric variations.
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Miyasato, Hugo Heidy 1986. "Modeling of the clutch squeal phenomenon and practical possibilities for its mitigation = Modelagem do fenômeno de squeal de embreagens e possibilidades práticas para sua atenuação." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265816.
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Orientador: Milton Dias JuniorTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: O trem de potência é um sistema complexo, uma vez que envolve a interação entre componentes tais como o motor, a embreagem, a transmissão e as rodas. Diversos fenômenos de ruído, vibração e sua severidade (NVH) podem surgir durante o seu funcionamento (judder, clonk, shuffle, rattle, etc.). O squeal de embreagens é um fenômeno relativamente novo desse sistema e ele surge como um ruído de tom único, especialmente em situações de partida na fase de modulação da embreagem. Componentes tais como as molas cushion, membrana e de retrocesso foram modeladas a fim de permitir a criação de diferentes projetos e combinações em termos de posição e propriedades físicas. Um mecanismo de estabilização para a placa de pressão foi testado numericamente para servir como uma alternativa para o sistema quando não existem possibilidades de modificações nos seus parâmetros. Discos de embreagens reais contêm imperfeições devido à utilização, tolerâncias da manufatura, etc. Para levar esses fatos em consideração, um elemento rotativo de rigidez/amortecimento viscoso com atrito foi criado para representar as molas cushion e suportar distribuições arbitrárias ao longo do perímetro do disco, permitindo que cada elemento tenha suas próprias características. A suposição de amortecimento viscoso introduziu termos relacionados à velocidade de rotação do disco de embreagem na matriz de rigidez. Simulações com pequenos erros de posicionamento nas molas cushion geraram acoplamento entre a vibração axial da placa de pressão e seus deslocamentos angulares. A mola membrana foi modelada como uma alavanca, permitindo a introdução de medições. Isso foi importante para identificar regiões de rigidez negativa e positiva, explicando sua interação com uma curva de cushion real. As molas de retrocesso foram modeladas, resultando numa representação matricial na qual foi possível gerar termos de rigidez positiva fora da diagonal principal. Finalmente, o mecanismo de estabilização para o sistema consistiu de outro disco conectado à placa de pressão. Quando as propriedades do dispositivo foram ajustadas apropriadamente, ele foi efetivo em uma situação de veering. Nessa condição, as coordenadas de ambos os discos foram combinadas nas formas modais, causando movimentos de wobbling fora de fase que resultaram em dissipação de energia nos elementos de conexão
Abstract: The powertrain is a complex system, once that it involves the interaction between components such as the engine, the clutch, the transmission and the wheels. Several noise, vibration and harshness (NVH) phenomena may appear during its operation (judder, clonk, shuffle, rattle, etc.). Clutch squeal is a relatively new phenomenon of this system and it appears as a single tone noise, especially on a drive-off condition on the modulation phase of the clutch. Components such as the cushion, diaphragm and leaf springs were modelled to allow the creation of different designs and combinations in terms of position or physical properties. A stabilization device for the pressure plate was numerically tested to serve as an alternative to the system when there are no practical possibilities of modifications on its parameters. Real clutch discs contain imperfections due to usage, manufacturing tolerances, etc. To take these facts into consideration, a rotating stiffness/viscous damper element with friction was created to represent the cushion springs and support arbitrary distributions along the perimeter of the disc, allowing each element to have its own characteristics. The assumption of viscous damping introduced terms related to the clutch disc rotating speed on the stiffness matrix. Simulations with small position errors on the cushion spring generated coupling between the pressure plate axial vibration and its angular displacements. The diaphragm spring was modelled as a lever, allowing the introduction of measurements. It was important to identify regions of negative and positive stiffness, explaining its interaction with a real cushion curve. The leaf springs were modelled, which resulted on a matrix representation where it was possible to generate positive stiffness terms out of its main diagonal. Finally, the stabilization device for the system consisted of another disc connected to the pressure plate. When the device properties were properly adjusted, it was affective in a situation of veering. In this condition, the coordinates of both discs were combined on the mode shapes, causing out of phase wobbling motions, that resulted on energy dissipation on the connection elements
Doutorado
Mecanica dos Sólidos e Projeto Mecanico
Doutor em Engenharia Mecânica
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Pedchote, C. "Parameter estimation for non-linear systems: an application to vehicle dynamics." Thesis, Engineering Systems Department, 2009. http://hdl.handle.net/1826/3896.
Full textAbstract:
This work presents an investigation into the parameter estimation of suspension
components and the vertical motions of wheeled vehicles from experimental data. The
estimation problems considered were for suspension dampers, a single wheel station and
a full vehicle.
Using conventional methods (gradient-based (GB), Downhill Simplex (DS)) and
stochastic methods (Genetic Algorithm (GA) and Differential Evolution (DE)), three
major problems were encountered. These were concerned with the ability and consistency
of finding the global optimum solution, time consumption in the estimation process, and
the difficulties in setting the algorithm's control parameters. To overcome these
problems, a new technique named the discrete variable Hybrid Differential Evolution
(dvHDE) method is presented.
The new dvHDE method employs an integer-encoding technique and treats all
parameters involved in the same unified way as discrete variables, and embeds two
mechanisms that can be used to deal with convergence difficulties and reduce the time
consumed in the optimisation process. The dvHDE algorithm has been validated against
the conventional GB, DS and DE techniques and was shown to be more efficient and
effective in all but the simplest cases. Its robustness was demonstrated by its application
to a number of vehicle related problems of increasing complexity. These include case
studies involving parameter estimation using experimental data from tests on automotive
dampers, a single wheel station and a full vehicle. The investigation has shown that the
proposed dvHDE method, when compared to the other methods, was the best for finding
the global optimum solutions in a short time. It is recommended for nonlinear vehicle
suspension models and other similar systems.
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Pedchote, Chamnarn. "Parameter estimation for non-linear systems : an application to vehicle dynamics." Thesis, Cranfield University, 2003. http://dspace.lib.cranfield.ac.uk/handle/1826/3896.
Full textAbstract:
This work presents an investigation into the parameter estimation of suspension components and the vertical motions of wheeled vehicles from experimental data. The estimation problems considered were for suspension dampers, a single wheel station and a full vehicle. Using conventional methods (gradient-based (GB), Downhill Simplex (DS)) and stochastic methods (Genetic Algorithm (GA) and Differential Evolution (DE)), three major problems were encountered. These were concerned with the ability and consistency of finding the global optimum solution, time consumption in the estimation process, and the difficulties in setting the algorithm's control parameters. To overcome these problems, a new technique named the discrete variable Hybrid Differential Evolution (dvHDE) method is presented. The new dvHDE method employs an integer-encoding technique and treats all parameters involved in the same unified way as discrete variables, and embeds two mechanisms that can be used to deal with convergence difficulties and reduce the time consumed in the optimisation process. The dvHDE algorithm has been validated against the conventional GB, DS and DE techniques and was shown to be more efficient and effective in all but the simplest cases. Its robustness was demonstrated by its application to a number of vehicle related problems of increasing complexity. These include case studies involving parameter estimation using experimental data from tests on automotive dampers, a single wheel station and a full vehicle. The investigation has shown that the proposed dvHDE method, when compared to the other methods, was the best for finding the global optimum solutions in a short time. It is recommended for nonlinear vehicle suspension models and other similar systems.
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Moodley, Kirshnee. "The fitting of statistical distributions to wind data in coastal areas of South Africa." Thesis, Nelson Mandela Metropolitan University, 2013.
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Coastal South African cities like Port Elizabeth are said to have a strong potential for wind energy. This study aims to model wind data in order to be able assess the power potential belonging to a given site. The main challenge in modelling wind direction data is that it is categorized as circular data and therefore requires special techniques for handling that are different from usual statistical samples. Statistical tools such as descriptive measures and distribution fitting, were re-invented for directional data by researchers in this field. The von Mises distribution is a predominant distribution in circular statistics and is commonly used to describe wind directions. In this study, the circular principles described by previous researchers were developed by using the statistical software, Mathematica. Graphical methods to present the wind data were developed to give an overview of the behaviour of the winds in any given area. Data collected at Coega, an area near Port Elizabeth, South Africa, was used to illustrate the models which were established in this study. Circular distributions were fit to the directional data in order to make appropriate conclusions about the prevailing wind directions in this area.
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Zararsiz, Zarife. "On an epidemic model given by a stochastic differential equation." Thesis, Växjö University, School of Mathematics and Systems Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-5747.
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Siddique, Sharif Rayhan. "Development of policies to ameliorate the environmental impact of cars in Perth City, using the results of a stated preference survey and air pollution modelling." University of Western Australia. Faculty of Business, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0165.
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[Truncated abstract] Air pollution is increasingly perceived to be a serious intangible threat to humanity, with air quality continuing to deteriorate in most urban areas. The main sources of inner city pollution are motor vehicles, which generate emissions from the tail pipe as well as by evaporation. These contain toxic gaseous components which have adverse health effects. The major components are carbon monoxide (CO), nitrogen dioxide (NO2), nitric oxide (NO), sulphur dioxide (SO2), particulates (PM10), and volatile organic compounds (VOC). CO and oxides of nitrogen (NOx) are major emissions from cars. This study focuses on pollutant concentration in Perth city and has sought to develop measures to improve air quality. To estimate concentrations, the study develops air pollution models for CO and NOx; on the basis of the model estimates, effective policy is devised to improve the air quality by managing travel to the city. Two peaks, due to traffic, are observed in hourly CO and NOx concentrations. Unlike traffic, however, the morning peak does not reach the level of the afternoon peak. The reasons for this divergence are assessed and quantified. Separate causal models of hourly concentrations of CO and NOx explain their fluctuations accurately. They take account of the complex effects of the urban street canyon and winds in the city. The angle of incidence of the wind has significant impact on pollution level; a wind flow from the south-west increases pollution and wind from the north-east decreases it. The models have been shown to be equivalent to engineering and scientific models in estimating emission rate in the context of street canyons. However the study models are much more precise in the Perth context. ... The models are used to calculate the marginal effects for all attributes and elasticity for fuel price. In almost all attributes the non-work group is more responsive than the work group. Finally, the SP model results are integrated into an econometric model for the purpose of prediction. The travel behaviour prediction is used to estimate the policy impact on air quality. The benefit from the air quality improvement is reported in terms of life saved. The estimated relationships between probability of death and air pollution determines the number of lives that could be saved under various policy scenarios. A ratio of benefits to the financial and perceived sacrifices by drivers is calculated to compare the effectiveness of the suggested policies. A car size charge policy was found to be the most cost effective measure to ameliorate the environmental impact of cars in Perth, with a morning peak entry time charge being almost as cost effective. The study demonstrates the need for appropriate modelling of air pollution and travel behaviour. It brings together analytical methods at three levels of causality, vehicle to air pollution, charge to travel response, and air pollution to health.
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Damay, Nicolas. "Contribution à la modélisation thermique de packs batteries LiFePO4 pour véhicules décarbonés." Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2242/document.
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Cette thèse s’inscrit dans la problématique mondiale qu’est la gestion de l’énergie en se focalisant sur les batteries pour véhicules électriques ou hybrides. Celles-ci subissent des contraintes particulièrement sévères qui les font s’échauffer rapidement. Afin d’éviter le risque d’un vieillissement prématuré tout en limitant les surcoûts, il convient de dimensionner la batterie et son système de refroidissement de manière optimale. Les modèles thermiques proposés permettent ce dimensionnement optimal. Le modèle utilisé pour les pertes électriques a été amélioré pour être désormais stable lors de simulations de longs trajets. L’analyse fine du fort couplage entre les phénomènes thermiques et électrochimiques a mené à de nouvelles méthodes de caractérisations. Le « découplage » de ces phénomènes permet d’améliorer grandement les prédictions des modèles, notamment dans des plages de fonctionnement très contraignantes (basse température et très forte puissance). La précision est garantie à 1 °C, même pour des simulations de plusieurs heuresThis PhD thesis is included in the global energy-management issue. lts focus is on battery packs for electric or hybrid vehicles. The latter are bound to heat quickly because they're receiving high stresses during operation. Thus, to avoid accelerating the aging process while maintaining a minimal cost, the battery and its cooling system have to be sized optimally. The proposed thermal models can be used to reach this optimal sizing. The electrical losses model has been improved to become stable during the simulations of long driving cycles. The precise study of the strong coupling between electrochemical and thermal behaviors has led to new characterization methods. The "decoupling" of these phenomena improves significantly the models predictions, especially in very stressed operation ranges (low temperature and high power).The precision is better than 1° C, even for several-hours simulations
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Cerbone, G. (Giuseppe). "Machine learning in engineering : techniques to speed up numerical optimization." Thesis, 1992. http://hdl.handle.net/1957/36513.
Full textAbstract:
Many important application problems in engineering can be formalized as nonlinear
optimization tasks. However, numerical methods for solving such problems
are brittle and do not scale well. For example, these methods depend critically
on choosing a good starting point from which to perform the optimization search.
In high-dimensional spaces, numerical methods have difficulty finding solutions
that are even locally optimal. The objective of this thesis is to demonstrate how
machine learning techniques can improve the performance of numerical optimizers
and facilitate optimization in engineering design.
The machine learning methods have been tested in the domain of 2-dimensional
structural design, where the goal is to find a truss of minimum weight that bears a
set of fixed loads. Trusses are constructed from pure tension and pure compression
members. The difference in the load-bearing properties of tension and compression
members causes the gradient of the objective function to be discontinuous, and this
prevents the application of powerful gradient-based optimization algorithms in this
domain.
In this thesis, the approach to numerical optimization is to find ways of transforming
the initial problem into a selected set of subproblems where efficient,
gradient-based algorithms can be applied. This is achieved by a three-step "compilation"
process.
The first step is to apply speedup learning techniques to partition the overall
optimization task into sub-problems for which the gradient is continuous. Then,
the second step is to further simplify each sub-problem by using inductive learning
techniques to identify regularities and exploit them to reduce the number of
independent variables.
Unfortunately, these first two steps have the potential to produce an exponential
number of sub-problems. Hence, in the third step, selection rules are derived
to identify those sub-problems that are most likely to contain the global optimum.
The numerical optimization procedures are only applied to these selected
sub-problems.
To identify good sub-problems, a novel ID3-like inductive learning algorithm
called UTILITYID3 is applied to a collection of training examples to discover
selection rules. These rules analyze the problem statement and identify a small
number of sub-problems (typically 3) that are likely to contain the global optimum.
In the domain of 2-dimensional structural design, the combination of these
three steps yields a 6-fold speedup in the time required to find an optimal solution.
Furthermore, it turns out that this method is less reliant on a good starting point
for optimization.
The methods developed in this problem show promise of being applied to a
wide range of numerical optimization problems in engineering design.Graduation date: 1992
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Roshan, Usman Waheed. "Algorithmic techniques for improving the speed and accuracy of phylogenetic methods." Thesis, 2004. http://hdl.handle.net/2152/2181.
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Li, Xiaowei 1970 May 5. "High-speed and high-saturation-current partially depleted absorber photodetecters [i.e. photodetectors." 2004. http://hdl.handle.net/2152/12696.
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Lingam, Naga Sasidhar. "Low power design techniques for high speed pipelined ADCs." Thesis, 2009. http://hdl.handle.net/1957/10294.
Full textAbstract:
Real world is analog but the processing of signals can best be done in digital
domain. So the need for Analog to Digital Converters(ADCs) is ever rising as
more and more applications set in. With the advent of mobile technology, power
in electronic equipment is being driven down to get more battery life. Because of
their ubiquitous nature, ADCs are prime blocks in the signal chain in which power
is intended to be reduced. In this thesis, four techniques to reduce power in high
speed pipelined ADCs have been proposed. The first is a capacitor and opamp
sharing technique that reduces the load on the first stage opamp by three fold.
The second is a capacitor reset technique that aids removing the sample and hold
block to reduce power. The third is a modified MDAC which can take rail-to-rail
input swing to get an extra bit thus getting rid of a power hungry opamp. The
fourth is a hybrid architecture which makes use of an asynchronous SAR ADC
as the backend of a pipelined ADC to save power. Measurement and simulation
results that prove the efficiency of the proposed techniques are presented.Graduation date: 2009
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Janse, van Rensburg Neil. "Time delay in a semi-active damper." Diss., 2001. http://hdl.handle.net/2263/26012.
Full textAbstract:
In this study the feasibility of two mathematical models of the dynamics of a hydraulic bypass valve used on semi-active suspension systems for heavy vehicles is investigated. It is envisaged that similar models will eventually be incorporated into a full vehicle, three dimensional simulation study. The valve system contains an electro-hydraulic pilot valve circuit, a logic element, a damper and four check valves in a rectifier configuration. Models were compiled from first principles in the MATLAB environment and with the commercial fluid power simulation software, AMESim. The numerical methods used in the MATLAB model were found to be incapable of solving the stiff, nonlinear and discontinuous governing equations efficiently, while AMESim is very capable of handling detailed and complex fluid power models. Experimental work was conducted to determine certain steady state model parameters and to obtain dynamic performance data with which to validate model integrity. Several external factors influenced the valve behaviour during experiments making data extraction challenging. Simple first order assumptions accounting for the external influences on the valve therefore had to be included in the models. If this is done the basic dynamic behaviour of the valve system is matched well by the models. In general, the number of unknown parameters associated with fluid power systems accounted for the largest portion of the error between the simulated and measured response. The model as developed proved the possibility of creating highly accurate models but also indicated the amount of effort needed for their compilation.Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2007.
Mechanical and Aeronautical Engineering
unrestricted
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Stasinopoulos, Peter. "A system dynamics approach to life cycle assessment." Phd thesis, 2013. http://hdl.handle.net/1885/150676.
Full textAbstract:
Cars consume a large amount of energy and material resources, and generate large environmental impacts, through their production, use, and disposal. Some automotive engineers use the life cycle assessment (LCA) method to estimate and understand these environmental impacts arising from their design decisions. The standard LCA method, however, makes some limiting assumptions that exclude changes in parameter values over time. This lack of the temporal dimension leads to uncertainty in estimates, especially for new, high-volume, long-life products, such as cars. The aim of this thesis is to explore the value and challenges of an LCA method that can account for changes in resource consumptions and environmental impacts over time. This thesis modifies the standard LCA method to include some dynamics-the way that the state of a system changes over time in response to internally-generated and externally-imposed forces. A case study considers the technological intervention of replacing steel with lightweight materials in passenger cars in Australia. It considers the dynamics of the wider 'car system' at the level of the product fleet and resource flows, but not at the level of the environmental impacts. This thesis takes a System Dynamics (SD) approach by developing a computational model, a hypothesis of how the system works. The model explains the growth in the Australian car-fleet fuel consumption despite persistent policy intervention by government to decrease fuel consumption, compliance and technology innovation by car manufacturers, and shifts in transportation preferences to non-car modes by travellers. The model also allows the exploration of future scenarios wherein some car manufacturers adopt lightweight-material components and battery-electric powertrains. The computed values are used in spreadsheet calculations of resource flows and environmental impacts. The simulations of the SD model estimate that many resource benefits of lightweight cars take decades to accumulate because steel cars drain out of the fleet slowly. Furthermore, if the population of car travellers continues to grow, then oil depletion and growth in urban density could cause rapid declines in driving intensity and in the size of the petrol car fleet. Low driving intensity makes it difficult to recover the high energy investment in lightweight materials. Finally, the adoption of battery-electric cars enables car travellers to avoid most effects of oil depletion, but traffic congestion could still cause moderate declines in driving intensity and in the car fleet. The inclusion of the dynamics in an LCA study leads to surprising insights-some computational parameters, usually assumed to be constants or fixed functions of time, are considerably nonlinear. The results of the case study suggest that mass-reduction and similar 'efficiency' interventions are less effective than intended because the balancing loops and buffers of the system prevent parameters from operating in critical ranges that shift feedback loop dominance. The considerable investment into such technological interventions could be redirected, for greater effect, to policy interventions that target fuel security and traffic congestion through the behaviour and decision-making of travellers. The superiority of such interventions can be difficult to identify with a linear worldview of complex systems.
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Ricapito, David Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "A study of inverted wings with endplates in ground effect." 2007. http://handle.unsw.edu.au/1959.4/40883.
Full textAbstract:
An inverted wing with various endplate configurations was investigated at two different angles of incidence. A moving ground was designed and constructed for use in the UNSW T1 wind tunnel. The test cases were investigated in ground effect using the moving ground. Measurements and observations were obtained using laser sheet flow visualisation and laser doppler anemometry. Computational fluid dynamics models of the test cases were run to gain further understanding of the flow field generated when using inverted wings with endplates. The computational fluid dynamics models correlated well to the experimental results.
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"An intelligent vehicle security system based on human behaviors modeling." 2006. http://library.cuhk.edu.hk/record=b5892893.
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by Meng Xiaoning.Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.
Includes bibliographical references (leaves 99-106).
Abstracts in English and Chinese.
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Motivation --- p.1
Chapter 1.2 --- Overview --- p.2
Chapter 1.3 --- Organization of the Thesis --- p.3
Chapter 2 --- Related Research --- p.6
Chapter 2.1 --- Information Technology in Cars --- p.6
Chapter 2.2 --- Anti-theft Protection --- p.8
Chapter 2.3 --- Learning Human Behaviors --- p.10
Chapter 2.4 --- Neural Network Learning --- p.11
Chapter 3 --- Experimental Design --- p.14
Chapter 3.1 --- Overview --- p.14
Chapter 3.2 --- Driving Simulation Subsystem --- p.14
Chapter 3.3 --- Data Sensing and Capturing Subsystem --- p.15
Chapter 3.4 --- Data Analysis Subsystem --- p.17
Chapter 4 --- Data Preprocessing for Feature Selection --- p.23
Chapter 4.1 --- Introduction --- p.23
Chapter 4.2 --- Fast Fourier Transform --- p.23
Chapter 4.3 --- Principal Component Analysis --- p.24
Chapter 4.4 --- Independent Component Analysis --- p.26
Chapter 5 --- Classification via Support Vector Machine --- p.28
Chapter 5.1 --- Introduction --- p.28
Chapter 5.1.1 --- Why Using Support Vector Machine --- p.28
Chapter 5.1.2 --- Mathematic Description --- p.29
Chapter 5.2 --- Problem Formulation --- p.31
Chapter 5.3 --- Approach --- p.31
Chapter 5.4 --- Experimental Results --- p.34
Chapter 5.4.1 --- Preprocess Data Analysis --- p.34
Chapter 5.4.2 --- Models Design --- p.37
Chapter 5.5 --- Discussion --- p.44
Chapter 6 --- Evaluation via Hidden Markov Model --- p.47
Chapter 6.1 --- Introduction --- p.47
Chapter 6.1.1 --- Why Using Hidden Markov Model --- p.48
Chapter 6.1.2 --- Mathematic Description --- p.50
Chapter 6.2 --- Problem Formulation --- p.51
Chapter 6.3 --- Approach --- p.53
Chapter 6.4 --- Experimental Results --- p.56
Chapter 6.4.1 --- Model-to-model Measure --- p.56
Chapter 6.4.2 --- Human-to-model Measure --- p.63
Chapter 6.4.3 --- Parameters Optimization --- p.66
Chapter 6.5 --- Discussion --- p.69
Chapter 7 --- System Design and Implementation --- p.71
Chapter 7.1 --- Introduction --- p.71
Chapter 7.2 --- Hardware --- p.72
Chapter 7.3 --- Software --- p.78
Chapter 7.4 --- System Demonstration --- p.80
Chapter 8 --- Conclusion and Future Work --- p.82
Chapter 8.1 --- Contributions --- p.82
Chapter 8.2 --- Future Work --- p.84
Chapter A --- Hidden Markov Model Training --- p.87
Chapter A.1 --- Forward-backward Algorithm --- p.87
Chapter A.2 --- Baum-Welch Algorithm --- p.87
Chapter B --- Human Driving Behavior Data --- p.90
Chapter C --- Publications Resulted from the Study --- p.98
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Regier, Naomi Kay. "Time series analysis of power requirements for tillage tools." 1986. http://hdl.handle.net/2097/22137.
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Quigley, Christopher John 1962. "Refueling and evaporative emissions of volatile organic compounds from gasoline powered motor vehicles." Thesis, 2007. http://hdl.handle.net/2152/3642.
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The United States Environmental Protection Agency has estimated that over 111 million people reside in areas that exceed the National Ambient Air Quality Standards for ozone. One major source of the chemical precursors (nitrogen dioxides and volatile organic compounds (VOCs)) for ozone are motor vehicles. The overall goal of this research is to improve the knowledge base related to VOC refueling and evaporative emissions from motor vehicles. Refueling, running loss, hot soak, and diurnal loss total and speciated VOC emissions were investigated. A total of 12 uncontrolled refueling events were completed and involved the determination of volumetric flow rates of gasoline vapor during refueling, as well as total and speciated VOC concentrations. Total VOC emissions were compared with two commonly used algorithms. Speciated VOC vapor profiles were compared with two published gasoline vapor profiles and theoretical predictions based on knowledge of liquid composition and environmental conditions. An evaluation of refueling emissions impacts on ozone formation potentials using MIR was completed and results were compared against speciated emissions and MOBILE-based total VOC emissions estimates coupled with a default speciation profile. Refueling VOC emissions and resultant ozone formation potential may be underestimated in existing emission inventories, particularly during the summer ozone season, A model was developed to predict the speciation of VOCs associated with evaporative emissions from motor vehicles. Model-predicted speciation profiles were evaluated using SHED studies. Running loss, hot soak and diurnal emissions were included in each test. Total VOC emissions measured during each test were compared against MOBILE6 predicted emissions. An evaluation of evaporative emissions impacts on ozone formation potentials using MIR was completed, comparing measured and predicted emissions. The measured:predicted speciation results ranged between 0.93 and 1.11 and had an average value of 1.02. For the conditions tested, MOBILE6 underestimated evaporative emissions in 20 of 24 comparisons. MOBILE6-based ozone formation potentials may be underestimated.
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Compton, Andrea Jean. "The correlation of sea surface temperatures, sea level pressure and vertical wind shear with ten tropical cyclones between 1981-2010." Thesis, 2013. http://hdl.handle.net/1805/3669.
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Vaezi, Masoud. "Modeling and control of hydraulic wind power transfer systems." Thesis, 2014. http://hdl.handle.net/1805/6172.
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Indiana University-Purdue University Indianapolis (IUPUI)Hydraulic wind power transfer systems deliver the captured energy by the blades to the generators differently. In the conventional systems this task is carried out by a gearbox or an intermediate medium. New generation of wind power systems transfer the captured energy by means of high-pressure hydraulic fluids. A hydraulic pump is connected to the blades shaft at a high distance from the ground, in nacelle, to pressurize a hydraulic flow down to ground level equipment through hoses. Multiple wind turbines can also pressurize a flow sending to a single hose toward the generator. The pressurized flow carries a large amount of energy which will be transferred to the mechanical energy by a hydraulic motor. Finally, a generator is connected to the hydraulic motor to generate electrical power. This hydraulic system runs under two main disturbances, wind speed fluctuations and load variations. Intermittent nature of the wind applies a fluctuating torque on the hydraulic pump shaft. Also, variations of the consumed electrical power by the grid cause a considerable load disturbance on the system. This thesis studies the hydraulic wind power transfer systems. To get a better understanding, a mathematical model of the system is developed and studied utilizing the governing equations for every single hydraulic component in the system. The mathematical model embodies nonlinearities which are inherited from the hydraulic components such as check valves, proportional valves, pressure relief valves, etc. An experimental prototype of the hydraulic wind power transfer systems is designed and implemented to study the dynamic behavior and operation of the system. The provided nonlinear mathematical model is then validated by experimental result from the prototype. Moreover, this thesis develops a control system for the hydraulic wind power transfer systems. To maintain a fixed frequency electrical voltage by the system, the generator should remain at a constant rotational speed. The fluctuating wind speed from the upstream, and the load variations from the downstream apply considerable disturbances on the system. A controller is designed and implemented to regulate the flow in the proportional valve and as a consequence the generator maintains its constant speed compensating for load and wind turbine disturbances. The control system is applied to the mathematical model as well as the experimental prototype by utilizing MATLAB/Simulink and dSPACE 1104 fast prototyping hardware and the results are compared.
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Lawrence, Tom Marquis. "Characterization and Measurement of Hybrid Gas Journal Bearings." 2012. http://hdl.handle.net/1805/2926.
Full textAbstract:
Indiana University-Purdue University Indianapolis (IUPUI)This thesis concentrates on the study of hybrid gas journal bearings (bearings with externally pressurized mass addition). It differs from most work in that it goes back to “basics” to explore the hydrodynamic phenomena in the bearing gap. The thesis compares geometrically identical bearings with 2 configurations of external pressurization, porous liners where mass-addition compensation is varied by varying the liner’s permeability, and bushings with 2 rows of 6 feedholes where the mass-addition compensation is varied by the feedhole diameter. Experimentally, prototype bearings with mass-addition compensation that spans 2 orders of magnitude with differing clearances are built and their aerostatic properties and mass addition characteristics are thoroughly tested. The fundamental equations for compressible, laminar, Poiseuille flow are used to suggest how the mass flow “compensation” should be mathematically modeled. This is back-checked against the experimental mass flow measurements and is used to determine a mass-addition compensation parameter (called Kmeas) for each prototype bushing. In so doing, the methodology of modeling and measuring the mass addition in a hybrid gas bearing is re-examined and an innovative, practical, and simple method is found that makes it possible to make an “apples-to-apples” comparison between different configurations of external pressurization. This mass addition model is used in conjunction with the Reynolds equation to perform theory-based numerical analysis of virtual hybrid gas journal bearings (CFD experiments). The first CFD experiments performed use virtual bearings modeled to be identical to the experimental prototypes and replicate the experimental work. The results are compared and the CFD model is validated. The ontological significance of appropriate dimensionless similitude parameters is re-examined and a, previously lacking, complete set of similitude factors is found for hybrid bearings. A new practical method is developed to study in unprecedented detail the aerostatic component of the hybrid bearings. It is used to definitively compare the feedhole bearings to the porous liner bearings. The hydrostatic bearing efficiency (HBE) is defined and it is determined that the maximum achievable hydrostatic bearing efficiency (MAHBE) is determined solely by the bearing’s mass addition configuration. The MAHBE of the porous liner bearings is determined to be over 5 times that of the feedhole bearings. The method also presents a means to tune the Kmeas to the clearance to achieve the MAHBE as well as giving a complete mapping of the hitherto misunderstood complex shapes of aerostatic load versus radial deflection curves. This method also rediscovers the obscure phenomenon of static instability which is called in this thesis the “near surface effect” and appears to be the first work to present a practical method to predict the range of static instability and quantify its resultant stiffness fall-off. It determines that porous liner type bearings are not subject to the phenomenon which appears for feedhole type bearings when the clearance exceeds a critical value relative to its mass-addition compensation. The standing pressure waves of hydrostatic and hybrid bearings with the 2 configurations of external pressurization as well as a geometrically identical hydrodynamic bearing are studied in detail under the methodology of the “CFD microscope”. This method is used to characterize and identify the development, growth, and movement of the pressure wave extrema with increased hydrodynamic action (either increasing speed or increasing eccentricity). This method is also used to determine the “cause” of the “near surface effect”. A gedanken experiment is performed based on these results which indicates that a bearing with a “stronger aerostatic strength” component should be more stable than one with a low aerostatic strength component. Numerical instability “speed limits” are found that are also related to the hydrostatic strength of the bearing. The local conditions in the standing waves are characterized in terms of their local Mach number, Knudsen number, Reynolds number, and Taylor Number. It is concluded that low eccentricity bearing whirl can be attributed to the off load-line orientation of the bearing load force caused by the overlay of the hydrodynamic bearing standing wave onto the hydrostatic bearing wave of the hybrid bearing, whereas it is hypothesized that aperiodic and random self-excited vibration which occurs at high eccentricity, as reported in the literature, is probably due to shock waves, turbulence, near surface effect, and slip at local areas of the standing wave.
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Shimoga, Muddappa Vinay Kumar. "Electrochemical model based condition monitoring of a Li-ion battery using fuzzy logic." Thesis, 2014. http://hdl.handle.net/1805/5588.
Full textAbstract:
Indiana University-Purdue University Indianapolis (IUPUI)There is a strong urge for advanced diagnosis method, especially in high power battery packs and high energy density cell design applications, such as electric vehicle (EV) and hybrid electric vehicle segment, due to safety concerns. Accurate and robust diagnosis methods are required in order to optimize battery charge utilization and improve EV range. Battery faults cause significant model parameter variation affecting battery internal states and output. This work is focused on developing diagnosis method to reliably detect various faults inside lithium-ion cell using electrochemical model based observer and fuzzy logic algorithm, which is implementable in real-time. The internal states and outputs from battery plant model were compared against those from the electrochemical model based observer to generate the residuals. These residuals and states were further used in a fuzzy logic based residual evaluation algorithm in order to detect the battery faults. Simulation results show that the proposed methodology is able to detect various fault types including overcharge, over-discharge and aged battery quickly and reliably, thus providing an effective and accurate way of diagnosing li-ion battery faults.